Researcher Database

Kentaro Takagi
Field Science Center for Northern Biosphere Forest Research Station Teshio Experimental Forest
Associate Professor

Researcher Profile and Settings


  • Field Science Center for Northern Biosphere Forest Research Station Teshio Experimental Forest

Job Title

  • Associate Professor


  • Doctor (Earth and Environmental Science)(Hokkaido University)
  • Master (Environmental Science)(Hokkaido University)

J-Global ID

Research Interests

  • 炭素循環   物質循環   森林生態   農林気象   温暖化   炭素循環   物質循環   森林   Carbon Balance   Forest Ecology   Forest Ecology   Agricultural and Forest Meteorology   Global Warming   Carbon Balance   Forest   

Research Areas

  • Life sciences / Forest science
  • Environmental science/Agricultural science / Agricultural environmental and information engineering
  • Environmental science/Agricultural science / Agricultural environmental and information engineering
  • Environmental science/Agricultural science / Environmental dynamics

Academic & Professional Experience

  • 2011 - Today Hokkaido University Field Science Center for Northern Biosphere Associate Professor
  • 2011 - Today Hokkaido University Field Science Center for Northern Biosphere
  • 2009 - Today Field Science Center for Northern Biosphere, Hokkaido University Teshio Experimental Forest Director
  • 2007 - 2011 Hokkaido University Field Science Center for Northern Biosphere Assistant Professor
  • 2007 - 2011 Hokkaido University Field Science Center for Northern Biosphere
  • 2001 - 2007 Hokkaido University Field Science Center for Northern Biosphere
  • 2001 - 2007 Research Associate,Field Science Center for Northern Biosphere, Hokkaido University
  • 2000 - 2001 Hokkaido University Faculty of Agriculture
  • 2000 - 2001 Research Associate
  • 1997 - 1999 科学技術振興事業団 研究員
  • 1997 - 1999 Researcher,Japan Science and Technology Agency
  • 1999 アメリカ合衆国サンディエゴ州立大学 研究員
  • 1999 Ministry of Agriculture, Forestry and Fisheries
  • 1999 Researcher,San Diego State University


  •        - 1997  Hokkaido University
  •        - 1997  Hokkaido University  Graduate School, Division of Earth Environmental Science and Technology
  •        - 1994  Hokkaido University
  •        - 1994  Hokkaido University  Graduate School, Division of Environmental Science
  •        - 1992  Hokkaido University  Faculty of Agriculture
  •        - 1992  Hokkaido University  Faculty of Agriculture

Association Memberships

  • 日本森林学会   日本農業気象学会   日本農業気象学会北海道支部会   日本生態学会   The Japanese Forest Society   The Society of Agricultural Meteorology of Japan   Ecological Society of Japan   

Research Activities

Published Papers

  • Ben Bond-Lamberty, Danielle S. Christianson, Avni Malhotra, Stephanie C. Pennington, Debjani Sihi, Amir AghaKouchak, Hassan Anjileli, M. Altaf Arain, Juan J. Armesto, Samaneh Ashraf, Mioko Ataka, Dennis Baldocchi, Thomas Andrew Black, Nina Buchmann, Mariah S. Carbone, Shih Chieh Chang, Patrick Crill, Peter S. Curtis, Eric A. Davidson, Ankur R. Desai, John E. Drake, Tarek S. El-Madany, Michael Gavazzi, Carolyn Monika Görres, Christopher M. Gough, Michael Goulden, Jillian Gregg, Omar Gutiérrez del Arroyo, Jin Sheng He, Takashi Hirano, Anya Hopple, Holly Hughes, Järvi Järveoja, Rachhpal Jassal, Jinshi Jian, Haiming Kan, Jason Kaye, Yuji Kominami, Naishen Liang, David Lipson, Catriona A. Macdonald, Kadmiel Maseyk, Kayla Mathes, Marguerite Mauritz, Melanie A. Mayes, Steve McNulty, Guofang Miao, Mirco Migliavacca, Scott Miller, Chelcy F. Miniat, Jennifer G. Nietz, Mats B. Nilsson, Asko Noormets, Hamidreza Norouzi, Christine S. O’Connell, Bruce Osborne, Cecilio Oyonarte, Zhuo Pang, Matthias Peichl, Elise Pendall, Jorge F. Perez-Quezada, Claire L. Phillips, Richard P. Phillips, James W. Raich, Alexandre A. Renchon, Nadine K. Ruehr, Enrique P. Sánchez-Cañete, Matthew Saunders, Kathleen E. Savage, Marion Schrumpf, Russell L. Scott, Ulli Seibt, Whendee L. Silver, Wu Sun, Daphne Szutu, Kentaro Takagi, Masahiro Takagi, Munemasa Teramoto, Mark G. Tjoelker, Susan Trumbore, Masahito Ueyama, Rodrigo Vargas, Ruth K. Varner, Joseph Verfaillie, Christoph Vogel, Jinsong Wang, Greg Winston, Tana E. Wood, Juying Wu, Thomas Wutzler, Jiye Zeng, Tianshan Zha, Quan Zhang, Junliang Zou
    Global Change Biology 26 (12) 7268 - 7283 1354-1013 2020/12 
    © 2020 The Authors. Global Change Biology published by John Wiley & Sons Ltd Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil-to-atmosphere CO2 flux, commonly though imprecisely termed soil respiration (RS), is one of the largest carbon fluxes in the Earth system. An increasing number of high-frequency RS measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well. Such high frequency data are an invaluable resource for understanding GHG fluxes, but lack a central database or repository. Here we describe the lightweight, open-source COSORE (COntinuous SOil REspiration) database and software, that focuses on automated, continuous and long-term GHG flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation. Contributed datasets are mapped to a single, consistent standard, with metadata on contributors, geographic location, measurement conditions and ancillary data. The design emphasizes the importance of reproducibility, scientific transparency and open access to data. While being oriented towards continuously measured RS, the database design accommodates other soil-atmosphere measurements (e.g. ecosystem respiration, chamber-measured net ecosystem exchange, methane fluxes) as well as experimental treatments (heterotrophic only, etc.). We give brief examples of the types of analyses possible using this new community resource and describe its accompanying R software package.
  • Noboru Katayama, Osamu Kishida, Chikako Miyoshi, Shintaro Hayakashi, Kinya Ito, Rei Sakai, Aiko Naniwa, Hiroyuki Takahashi, Kentaro Takagi
    PLoS ONE 15 (12 December) 2020/12 
    © 2020 Katayama et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Anthropogenic disturbances in forest management practices can affect wild edible plants. Soil scarification is a large-scale disturbance that may cause long-term reduction in productivity of edible dwarf bamboo, Sasa kurilensis, in northern Japan. For their effective and sustainable use, we need to understand the recovery process after such disturbances. At 14 study sites in the Teshio Experimental Forest of Hokkaido University where soil scarification had been conducted between 2 and 44 years prior, the number and stem diameter of old and young (newly emerged, edible) culms was recorded. At sites that were within 11 years of soil scarification, the proportion of old culms (<11%) was lower than in the control area where soil scarification had never been conducted. At sites where more than 15 years had passed since soil scarification, the relative number of old culms was nearly equal to that in control area. Additionally, the number of young culms increased with an increasing number of old culms. These results suggest that recovery of productivity (in term of number) of edible culms may take a few decades. In contrast, the culm diameter of young culms increased linearly with time since soil scarification, but the 95% confidence interval in this relationship suggests that dwarf bamboo can produce thick edible culms soon after soil scarification. These findings will provide useful insights into how to obtain high quality bamboo culms following anthropogenic disturbances in future.
  • Masahito Ueyama, Kazuhito Ichii, Hideki Kobayashi, Tomo'omi Kumagai, Jason Beringer, Lutz Merbold, Eugenie S. Euskirchen, Takashi Hirano, Luca Belelli Marchesini, Dennis Baldocchi, Taku M. Saitoh, Yasuko Mizoguchi, Keisuke Ono, Joon Kim, Andrej Varlagin, Minseok Kang, Takanori Shimizu, Yoshiko Kosugi, M. Syndonia Bret-Harte, Takashi Machimura, Yojiro Matsuura, Takeshi Ohta, Kentaro Takagi, Satoru Takanashi, Yukio Yasuda
    ENVIRONMENTAL RESEARCH LETTERS 15 (8) 1748-9326 2020/08 [Refereed][Not invited]
    Rising atmospheric CO(2)concentration ([CO2]) enhances photosynthesis and reduces transpiration at the leaf, ecosystem, and global scale via the CO(2)fertilization effect. The CO(2)fertilization effect is among the most important processes for predicting the terrestrial carbon budget and future climate, yet it has been elusive to quantify. For evaluating the CO(2)fertilization effect on land photosynthesis and transpiration, we developed a technique that isolated this effect from other confounding effects, such as changes in climate, using a noisy time series of observed land-atmosphere CO(2)and water vapor exchange. Here, we evaluate the magnitude of this effect from 2000 to 2014 globally based on constraint optimization of gross primary productivity (GPP) and evapotranspiration in a canopy photosynthesis model over 104 global eddy-covariance stations. We found a consistent increase of GPP (0.138 0.007% ppm(-1); percentile per rising ppm of [CO2]) and a concomitant decrease in transpiration (-0.073% 0.006% ppm(-1)) due to rising [CO2]. Enhanced GPP from CO(2)fertilization after the baseline year 2000 is, on average, 1.2% of global GPP, 12.4 g C m(-2)yr(-1)or 1.8 Pg C yr(-1)at the years from 2001 to 2014. Our result demonstrates that the current increase in [CO2] could potentially explain the recent land CO(2)sink at the global scale.
  • Lifei Sun, Kentaro Takagi, Munemasa Teramoto, Shintaro Hayakashi, Naishen Liang
    JOURNAL OF AGRICULTURAL METEOROLOGY 76 (3) 119 - 127 0021-8588 2020/07 
    To understand the magnitudes of temporal variation in soil respiration (R-s) and its spatial heterogeneity, and the effect of abiotic and biotic factors to cause the variation in a young plantation recovering after the clear-cutting of a mature forest, we analyzed 8 year R-s, microclimate, and vegetation data obtained in a young hybrid larch plantation with dense undergrowth of dwarf bamboo Sasa in northern Japan during snow-free periods from 2004 to 2014. R-s was measured by a multichannel automated chamber system and was resolved into two components, temperature sensitivity of respiration, Q(10), and temperature-normalized basal respiration at 10 degrees C, R-10. Volumetric soil water content affects both seasonal and inter-annual variation of R-s by suppressing R-10, whereas soil temperature affects only its seasonal variation. Vegetation recovery had significant effect on both temporal variation and spatial heterogeneity in R-s, although the tree and undergrowth Sasa had different contribution to these variations. Increase in the undergrowth Sasa PAI (plant area index) recovering after clear-cutting increased the R-s through the increase in Q(10), whereas the spatial heterogeneity in R-s was increased by the increase in the tree PAI through the increase in R-10. These results reveal that the soil water and vegetation has strong effect on the inter-annual variation of R-s and its spatial heterogeneity in the recovering young plantation, in spite of the strong exponential relationship of R-s with T-s in their seasonal variation. Although our results were obtained under the limited range in the inter-annual variation in seasonal mean T-s (< 2 degrees C), this may not be the unique case only in our study site and gives us a caution when predicting R-s in future wanner environment.
  • Erika Marumo, Kentaro Takagi, Kobayashi Makoto
    JOURNAL OF FOREST RESEARCH 25 (4) 285 - 290 1341-6979 2020/07 
    Bud-burst timing is one of the key factors to determine tree growth. Smaller trees are known to show earlier bud bursts, owing to the ontogeny in temperate forests. Snowpack is one of the factors affecting burst timing, especially that of small trees. Because small individuals were buried under snowpack until late spring, we hypothesized although the smaller individuals require less degree-day accumulation for their bud burst, the bud-burst timing of smaller individuals is not always earlier than that of larger trees. To test this hypothesis, we investigated the relationship between the height of individuals and the sum of degree-days required until the day of bud burst, as well as the relationship with the bud-burst timings for Acer mono and Quercus crispula over 2 years. As hypothesized, both species showed positive relationship between tree height and degree-days for budburst in both years. Conversely, there was negative relationship between tree height and the bud-burst timing for both species in both years. These results indicate small individuals tended to be late to reach an adequate temperature for bud burst due to the heavy snowpack, and the day of bud burst was sometime later for the seedlings as compared to the large trees in spite of the less accumulation of degree-day for the bud burst of smaller trees. These results suggest snow regime changes may influence the phenology not of large trees but of small trees, which could result in a differential influence of winter climate change on tree growth depending on the individual tree height.
  • Tomoko K. Akitsu, Tatsuro Nakaji, Toshiya Yoshida, Rei Sakai, Wataru Mamiya, Terigele, Kentaro Takagi, Yoshiaki Honda, Koji Kajiwara, Kenlo N. Nasahara
    Ecological Research 0912-3814 2020/05/25 [Refereed][Not invited]
  • Genki Katata, Kazuhide Matsuda, Atsuyuki Sorimachi, Mizuo Kajino, Kentaro Takagi
    Atmospheric Chemistry and Physics 20 (8) 4933 - 4949 1680-7316 2020/04 
    © 2020 Copernicus GmbH. All rights reserved. Dry deposition has an impact on nitrogen status in forest environments. However, the mechanism for the high dry-deposition rates of fine nitrate particles (NO3-) observed in forests remains unknown and is thus a potential source of error in chemical transport models (CTMs). Here, we modified and applied a multilayer land surface model coupled with dry-deposition and aerosol dynamic processes for a temperate mixed forest in Japan. This represents the first application of such a model to ammonium nitrate (NH4NO3) gas-particle conversion (gpc) and the aerosol water uptake of reactive nitrogen compounds. Thermodynamics, kinetics, and dry deposition for mixed inorganic particles are modeled by a triple-moment modal method. Data for inorganic mass and size-resolved total number concentrations measured by a filter pack and electrical low-pressure impactor in autumn were used for model inputs and subsequent numerical analysis. The model successfully reproduces turbulent fluxes observed above the canopy and vertical micrometeorological profiles noted in our previous studies. The sensitivity tests with and without gpc demonstrated clear changes in the inorganic mass and size-resolved total number concentrations within the canopy. The results also revealed that within-canopy evaporation of NH4NO3 under dry conditions significantly enhances the deposition flux of fine-NO3- and fine-NH4+ particles, while reducing the deposition flux of nitric acid gas (HNO3). As a result of the evaporation of particulate NH4NO3, the calculated daytime mass flux of fine NO3- over the canopy was 15 times higher in the scenario of "gpc" than in the scenario of "no gpc". This increase caused high contributions from particle deposition flux (NO3- and NH4+) to total nitrogen flux over the forest ecosystem (ĝˆ1/439 %), although the contribution of NH3 was still considerable. A dry-deposition scheme coupled with aerosol dynamics may be required to improve the predictive accuracy of chemical transport models for the surface concentration of inorganic reactive nitrogen.
  • Ai Hojo, Kentaro Takagi, Ram Avtar, Takeo Tadono, Futoshi Nakamura
    Remote Sensing 12 (3) 2020/02/01 
    © 2020 by the authors. In this study, we compared the accuracies of above-ground biomass (AGB) estimated by integrating ALOS (Advanced Land Observing Satellite) PALSAR (Phased-Array-Type L-Band Synthetic Aperture Radar) data and TanDEM-X-derived forest heights (TDX heights) at four scales from 1/4 to 25 ha in a hemi-boreal forest in Japan. The TDX heights developed in this study included nine canopy height models (CHMs) and three model-based forest heights (ModelHs); the nine CHMs were derived from the three digital surface models (DSMs) of (I) TDX 12 m DEM (digital elevation model) product, (II) TDX 90 m DEM product and (III) TDX 5 m DSM, which we developed from two TDX-TSX (TerraSAR-X) image pairs for reference, and the three digital terrain models (DTMs) of (i) an airborne Light Detection and Ranging (LiDAR)-based DTM (LiDAR DTM), (ii) a topography-based DTM and (iii) the Shuttle Radar Topography Mission (SRTM) DEM; the three ModelHs were developed from the two TDX-TSX image pairs used in (III) and the three DTMs (i to iii) with the Sinc inversion model. In total, 12 AGB estimation models were developed for comparison. In this study, we included the C-band SRTM DEM as one of the DTMs. According to Walker et al. (2007), the SRTM DEM serves as a DTM for most of the Earth's surface, except for the areas with extensive tree and/or shrub coverage, e.g., the boreal and Amazon regions. As our test site is located in a hemi-boreal zone with medium forest cover, we tested the ability of the SRTM DEM to serve as a DTM in our test site. This study especially aimed to analyze the capability of the two TDX DEM products (I and II) to estimate AGB in practice in the hemi-boreal region, and to examine how the different forest height creation methods (the simple DSM and DTM subtraction for the nine CHMs and the Sinc inversion model-based approach for the three ModelHs) and the different spatial resolutions of the three DSMs and three DTMs affected the AGB estimation results. We also conducted the slope-class analysis to see how the varying slopes influenced the AGB estimation accuracies. The results show that the combined use of the PALSAR data and the CHM derived from (I) TDX 12 m DEM and (i) LiDAR DTM achieved the highest AGB estimation accuracies across the scales (R2 ranged from 0.82 to 0.97), but the CHMs derived from (I) TDX 12 m DEM and another two DTMs, (ii) and (iii), showed low R2 values at any scales. In contrast, the two CHMs derived from (II) TDX 90 m DEM and both (i) LiDAR DTM and (iii) SRTM DEM showed high R2 values > 0.87 and 0.78, respectively, at the scales > 9.0 ha, but they yielded much lower R2 values at smaller scales. The three ModelHs gave the lowest R2 values across the scales (R2 ranged from 0.39 to 0.60). Analyzed by slope class at the 1.0 ha scale, however, all the 12 AGB estimation models yielded high R2 values > 0.66 at the lowest slope class (0° to 9.9°), including the three ModelHs (R2 ranged between 0.68 to 0.69). The two CHMs derived from (II) TDX 90 m DEM and both (i) LiDAR DTM and (iii) SRTM DEM showed R2 values of 0.80 and 0.71, respectively, at the lowest slope class, while the CHM derived from (I) TDX 12 m DEM and (i) LiDAR DTM showed high R2 values across the slope classes (R2 > 0.82). The results show that (I) TDX 12 m DEM had a high capability to estimate AGB, with a high accuracy across the scales and the slope classes in the form of CHM, but the use of (i) LiDAR DTM was required. On the other hand, (II) TDX 90 m DEM was able to achieve high AGB estimation accuracies not only with (i) LiDAR DTM, but also with (iii) SRTM DEM in the form of CHM, but it was limited to large scales > 9.0 ha; however, all the models developed in this study have the possibility to achieve higher AGB estimation accuracies at the 1.0 ha scale in flat terrains with slope < 10°. The analysis showed the strengths and limitations of each model, and it also indicates that the data creation methods, the spatial resolutions of datasets and topographic features affects the effective spatial scales for AGB mapping, and the optimal combinations of these features should be chosen to obtain high AGB estimation accuracies.
  • Jens Kattge, Gerhard Bönisch, Sandra Díaz, Sandra Lavorel, Iain Colin Prentice, Paul Leadley, Susanne Tautenhahn, Gijsbert D.A. Werner, Tuomas Aakala, Mehdi Abedi, Alicia T.R. Acosta, George C. Adamidis, Kairi Adamson, Masahiro Aiba, Cécile H. Albert, Julio M. Alcántara, Carolina Alcázar C, Izabela Aleixo, Hamada Ali, Bernard Amiaud, Christian Ammer, Mariano M. Amoroso, Madhur Anand, Carolyn Anderson, Niels Anten, Joseph Antos, Deborah Mattos Guimarães Apgaua, Tia Lynn Ashman, Degi Harja Asmara, Gregory P. Asner, Michael Aspinwall, Owen Atkin, Isabelle Aubin, Lars Baastrup-Spohr, Khadijeh Bahalkeh, Michael Bahn, Timothy Baker, William J. Baker, Jan P. Bakker, Dennis Baldocchi, Jennifer Baltzer, Arindam Banerjee, Anne Baranger, Jos Barlow, Diego R. Barneche, Zdravko Baruch, Denis Bastianelli, John Battles, William Bauerle, Marijn Bauters, Erika Bazzato, Michael Beckmann, Hans Beeckman, Carl Beierkuhnlein, Renee Bekker, Gavin Belfry, Michael Belluau, Mirela Beloiu, Raquel Benavides, Lahcen Benomar, Mary Lee Berdugo-Lattke, Erika Berenguer, Rodrigo Bergamin, Joana Bergmann, Marcos Bergmann Carlucci, Logan Berner, Markus Bernhardt-Römermann, Christof Bigler, Anne D. Bjorkman, Chris Blackman, Carolina Blanco, Benjamin Blonder, Dana Blumenthal, Kelly T. Bocanegra-González, Pascal Boeckx, Stephanie Bohlman, Katrin Böhning-Gaese, Laura Boisvert-Marsh, William Bond, Ben Bond-Lamberty, Arnoud Boom, Coline C.F. Boonman, Kauane Bordin, Elizabeth H. Boughton, Vanessa Boukili, David M.J.S. Bowman, Sandra Bravo, Marco Richard Brendel, Martin R. Broadley, Kerry A. Brown, Helge Bruelheide, Federico Brumnich, Hans Henrik Bruun, David Bruy, Serra W. Buchanan, Solveig Franziska Bucher, Nina Buchmann, Robert Buitenwerf, Daniel E. Bunker, Jana Bürger
    Global Change Biology 26 (1) 119 - 188 1354-1013 2020/01/01 
    © 2019 The Authors. Global Change Biology published by John Wiley & Sons Ltd Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait–environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
  • Kobayashi Makoto, Semyon Bryanin, Kentaro Takagi
    APPLIED SOIL ECOLOGY 144 1 - 7 0929-1393 2019/12 [Refereed][Not invited]
    Due to spring climate warming, snowpack has been decreasing and the snowmelt timing has simultaneously been advancing in the cool-temperate forests of northern Japan. To investigate the effect of advancing snowmelt at the end of the snow season on soil nitrogen dynamics via overwintering earthworms, we conducted a snow removal field experiment at the end of the snow season using mesocosms with and without earthworms. In this study, the differences in the effect of snow removal on soil nitrogen according to the presence/absence and body size of Eisenia japonica were also tested in both early spring (April) and late spring (May). The snow removal did not influence the survival rate, body weight, or cast production of E. japonica. In early spring, while the snow removal increased nitrification significantly by 61%, the effect of snow removal was similar irrespective of the earthworm treatments. This indicates that neither the presence of earthworms nor earthworm body size influences the effect of snow reductions at the end of the snow season on the soil nitrogen dynamics in early spring. On the other hand, in late spring, snow removal no longer had a significant effect on soil nitrogen dynamics, while ammonification and nitrification significantly increased by 195% and by 50%, respectively, in the mesocosms with adult earthworms compared to the mesocosms without E. japonica earthworms. These findings indicate that the effects of snow decrease and the simultaneous advancement of snowmelt timing at the end of the snow season on soil nitrogen appear only just after snowmelt; alternatively, the effect of earthworm body size on soil nitrogen dynamics is predominant in late spring in snowy cool-temperate forests.
  • Keiji Okada, Kentaro Takagi, Yui Nishida
    JOURNAL OF AGRICULTURAL METEOROLOGY 75 (4) 183 - 192 0021-8588 2019/10 
    Over a period of 9 years covering both disturbed and undisturbed periods, we evaluated long-term variations in water and light use efficiency (WUE, LUE) in a cool-temperate mixed forest in northern Hokkaido, Japan: our study clarified the relationship of WUE and LUE to environmental and vegetation variables. WUE and LUE markedly decreased after deforestation: they were negatively correlated with the seasonal variations in photosynthetically active radiation (PAR) and water vapor deficit, and LUE increased with the increase in the leaf area index (LAI) coincident with the vegetation recovery. Other environmental and vegetation variables did not explain the changes in the WUE and LUE. The effect of clear-cutting on LUE was well explained by the change in the LAI; on the other hand, vegetation composition (developed forest or young tree seedling with dense undergrowth) had little effect on the magnitude and variation of LUE. In contrast, the change in LAI had little effect on WUE, because WUE is more sensitive to the atmospheric water deficit than it is to vegetation structure.
  • Akiyoshi Nakahara, Kentaro Takagi, Atsuyuki Sorimachi, Genki Katata, Kazuhide Matsuda
    ATMOSPHERIC ENVIRONMENT 212 136 - 141 1352-2310 2019/09 
    Fine particulate matter (PM2.5) is one of most concerning air pollutants in East Asia. In order to further understand the dry deposition process of PM2.5, measurements were carried out in a cool-temperate forest located in a remote area of northern Japan. These measurements took into account the improvement of simulations by chemical transport models in this region. We measured the vertical profiles of fine (PM2.5), coarse aerosol components, HNO3, and other relevant gases using two denuder/filter-pack sampling systems together with three 4-stage filter-pack sampling systems from July 22, 2017 to August 07, 2017. The vertical profile measurements clearly showed the difference in dry deposition process between fine NO3- and fine SO42-. Concentration gradients of fine NO3- from over to under the canopy were significantly higher than those of fine SO42-. Since most of fine NO3- existed as NH4NO3, it was considered that these high gradients of NO3- were associated with the process of the conversion between NH4NO3 and HNO3/NH3. The concentration gradients of fine NO3- increased with the increase in daytime air temperature from over to under the canopy. The simulations of the thermodynamic equilibrium of NH4NO3 at canopy surface temperatures using ISORROPIA II showed that the equilibrium shift of NH4NO3 into the gas phase during the daytime hot canopy can decrease fine NO3- by approximately 9% when compared to normal atmospheric conditions. The volatilized HNO3 was most probably immediately removed by the canopy as the HNO3 concentrations near the canopy were extremely low. Therefore, the equilibrium shift enhanced the dry deposition of nitrogen within fine NO3-.
  • Maricar Aguilos, Clément Stahl, Benoit Burban, Bruno Hérault, Elodie Courtois, Sabrina Coste, Fabien Wagner, Camille Ziegler, Kentaro Takagi, Damien Bonal
    Forests 10 (1) 2018/12/26 
    © 2018 by the authors. Warmer and drier climates over Amazonia have been predicted for the next century with expected changes in regional water and carbon cycles. We examined the impact of interannual and seasonal variations in climate conditions on ecosystem-level evapotranspiration (ET) and water use efficiency (WUE) to determine key climatic drivers and anticipate the response of these ecosystems to climate change. We used daily climate and eddyflux data recorded at the Guyaflux site in French Guiana from 2004 to 2014. ET and WUE exhibited weak interannual variability. The main climatic driver of ET and WUE was global radiation (Rg), but relative extractable water (REW) and soil temperature (Ts) did also contribute. At the seasonal scale, ET and WUE showed a modal pattern driven by Rg, with maximum values for ET in July and August and for WUE at the beginning of the year. By removing radiation effects during water depleted periods, we showed that soil water stress strongly reduced ET. In contrast, drought conditions enhanced radiation-normalized WUE in almost all the years, suggesting that the lack of soil water had a more severe effect on ecosystem evapotranspiration than on photosynthesis. Our results are of major concern for tropical ecosystem modeling because they suggest that under future climate conditions, tropical forest ecosystems will be able to simultaneously adjust CO 2 and H 2 O fluxes. Yet, for tropical forests under future conditions, the direction of change in WUE at the ecosystem scale is hard to predict, since the impact of radiation on WUE is counterbalanced by adjustments to soil water limitations. Developing mechanistic models that fully integrate the processes associated with CO 2 and H 2 O flux control should help researchers understand and simulate future functional adjustments in these ecosystems.
  • Shin Nagai, Tomoko Akitsu, Taku M. Saitoh, Robert C. Busey, Karibu Fukuzawa, Yoshiaki Honda, Tomoaki Ichie, Reiko Ide, Hiroki Ikawa, Akira Iwasaki, Koki Iwao, Koji Kajiwara, Sinkyu Kang, Yongwon Kim, Kho Lip Khoon, Alexander V. Kononov, Yoshiko Kosugi, Takahisa Maeda, Wataru Mamiya, Masayuki Matsuoka, Trofim C. Maximov, Annette Menzel, Tomoaki Miura, Toshie Mizunuma, Tomoki Morozumi, Takeshi Motohka, Hiroyuki Muraoka, Hirohiko Nagano, Taro Nakai, Tatsuro Nakaji, Hiroyuki Oguma, Takeshi Ohta, Keisuke Ono, Runi Anak Sylvester Pungga, Roman E. Petrov, Rei Sakai, Christian Schunk, Seikoh Sekikawa, Ruslan Shakhmatov, Yowhan Son, Atsuko Sugimoto, Rikie Suzuki, Kentaro Takagi, Satoru Takanashi, Shunsuke Tei, Satoshi Tsuchida, Hirokazu Yamamoto, Eri Yamasaki, Megumi Yamashita, Tae Kyung Yoon, Toshiya Yoshida, Mitsunori Yoshimura, Shinpei Yoshitake, Matthew Wilkinson, Lisa Wingate, Kenlo Nishida Nasahara
    ECOLOGICAL RESEARCH 33 (6) 1091 - 1092 0912-3814 2018/11 [Refereed][Not invited]
    We report long-term continuous phenological and sky images taken by time-lapse cameras through the Phenological Eyes Network ( Accessed 29 May 2018) in various ecosystems from the Arctic to the tropics. Phenological images are useful in recording the year-to-year variability in the timing of flowering, leaf-flush, leaf-coloring, and leaf-fall and detecting the characteristics of phenological patterns and timing sensitivity among species and ecosystems. They can also help interpret variations in carbon, water, and heat cycling in terrestrial ecosystems, and be used to obtain ground-truth data for the validation of satellite-observed products. Sky images are useful in continuously recording atmospheric conditions and obtaining ground-truth data for the validation of cloud contamination and atmospheric noise present in satellite remote-sensing data. We have taken sky, forest canopy, forest floor, and shoot images of a range of tree species and landscapes, using time-lapse cameras installed on forest floors, towers, and rooftops. In total, 84 time-lapse cameras at 29 sites have taken 8 million images since 1999. Our images provide (1) long-term, continuous detailed records of plant phenology that are more quantitative than in situ visual phenological observations of index trees; (2) basic information to explain the responsiveness, vulnerability, and resilience of ecosystem canopies and their functions and services to changes in climate; and (3) ground-truthing for the validation of satellite remote-sensing observations.
  • Masahito Ueyama, Kota Yoshikawa, Kentaro Takagi
    ATMOSPHERIC ENVIRONMENT 184 110 - 120 1352-2310 2018/07 [Refereed][Not invited]
    Upland forests are thought to be methane (CH4) sinks due to oxidation by methanotrophs in aerobic soils. However, CH4 budget for upland forests are not well quantified at the ecosystem scale, when possible CH4 sources, such as small wet areas, exists in the ecosystem. Here, we quantified CH4 fluxes in a cool-temperate larch plantation based on four-year continuous measurements using the hyperbolic relaxed eddy accumulation (HREA) method and dynamic closed chambers with a laser-based analyzer. After filling data gaps for half-hourly data using machine-learning-based regressions, we found that the forest acted as a net CH4 source at the canopy scale: 30 +/- 11 mg CH4 m(-2) yr(-1) in 2014, 56 +/- 8 mg CH4 m(-2) yr(-1) in 2015, 154 +/- 5 mg CH4 m(-2) yr(-1) in 2016, and 132 +/- 6 mg CH4 m(-2) yr(-1) in 2017. Hotspot emissions from the edge of the pond could strongly contribute to the canopy-scale emissions. The magnitude of the hotspot emissions was 10-100 times greater than the order of the canopy-scale and chamber-based CH4 fluxes at the dry soils. The high temperatures with wet conditions stimulated the hotspot emissions, and thus induced canopy-scale CH4 emissions in the summer. Understanding and modeling the dynamics of hotspot emissions are important for quantifying CH4 budgets of upland forests. Micrometeorological measurements at various forests are required for revisiting CH4 budget of upland forests.
  • Shohei Nomura, Hitoshi Mukai, Yukio Terao, Kentaro Takagi, Maznorizan Mohamad, Mohad Firdaus Jahaya
    TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY 70 (1) 1426316  1600-0889 2018/01 [Refereed][Not invited]
    Evaluation of carbon dioxide (CO2) sinks in forest areas of East and Southeast Asia (especially tropical regions) is important for assessing CO2 budgets at the regional scale. To evaluate the CO2 flux of large forest areas, we collected vertical CO2 profiles over the forest using a CO2 sonde and measured surface CO2 concentrations around the forest using continuous CO2 measurement equipment. These observations were performed over a typical northern forest (Hokkaido) in Japan, a subtropical forest island (Iriomote Island) in Japan, and a tropical forest in Borneo Island. We detected the differences in CO2 vertical profiles between dawn and daytime, and at the upwind and downwind sites of the forests with the observational results from the CO2 sonde. We also clarified that CO2 concentrations during daytime at the downwind sites (affected by the forest) were systematically lower than those at the upwind sites (not affected by the forest). In contrast, CO2 concentrations during dawn at the downwind sites were larger than those at the upwind site. We estimated the CO2 fluxes (mu mol m(-2) s(-1)) at dawn and daytime of the forests from these observational results. The CO2 fluxes of Borneo's forest were very large (16.5 and -37.7 at dawn and daytime, respectively), whereas the CO2 fluxes of the forests in Hokkaido and Iriomote were lower (3.9 to 11.8 at dawn and -11.8 to -15.0 at daytime). These evaluated values were consistent with fluxes measured by the eddy-covariance method in the same region. Thus, use of the CO2 sonde to collect observations of CO2 vertical profiles was considered to be an effective method to verify CO2 absorption and emission in large forest areas. This method can also be used to evaluate dynamic CO2 absorption and emission processes in tropical forests.
  • Zhiyuan Zhang, Renduo Zhang, Alessandro Cescatti, Georg Wohlfahrt, Nina Buchmann, Juan Zhu, Guanhong Chen, Fernando Moyano, Jukka Pumpanen, Takashi Hirano, Kentaro Takagi, Lutz Merbold
    SCIENTIFIC REPORTS 7 (1) 2045-2322 2017/06 [Refereed][Not invited]
    The net ecosystem CO2 exchange is the result of the imbalance between the assimilation process (gross primary production, GPP) and ecosystem respiration (RE). The aim of this study was to investigate temperature sensitivities of these processes and the effect of climate warming on the annual terrestrial net ecosystem CO2 exchange globally in the boreal and temperate regions. A database of 403 site-years of ecosystem flux data at 101 sites in the world was collected and analyzed. Temperature sensitivities of rates of RE and GPP were quantified with Q(10), defined as the increase of RE (or GPP) rates with a temperature rise of 10 degrees C. Results showed that on the annual time scale, the intrinsic temperature sensitivity of GPP (Q(10sG)) was higher than or equivalent to the intrinsic temperature sensitivity of RE (Q(10sR)). Q(10sG) was negatively correlated to the mean annual temperature (MAT), whereas Q(10sR) was independent of MAT. The analysis of the current temperature sensitivities and net ecosystem production suggested that temperature rise might enhance the CO2 sink of terrestrial ecosystems both in the boreal and temperate regions. In addition, ecosystems in these regions with different plant functional types should sequester more CO2 with climate warming.
  • Kazuhito Ichii, Masahito Ueyama, Masayuki Kondo, Nobuko Saigusa, Joon Kim, Ma. Carmelita Alberto, Jonas Ardoe, Eugenie S. Euskirchen, Minseok Kang, Takashi Hirano, Joanna Joiner, Hideki Kobayashi, Luca Belelli Marchesini, Lutz Merbold, Akira Miyata, Taku M. Saitoh, Kentaro Takagi, Andrej Varlagin, M. Syndonia Bret-Harte, Kenzo Kitamura, Yoshiko Kosugi, Ayumi Kotani, Kireet Kumar, Sheng-Gong Li, Takashi Machimura, Yojiro Matsuura, Yasuko Mizoguchi, Takeshi Ohta, Sandipan Mukherjee, Yuji Yanagi, Yukio Yasuda, Yiping Zhang, Fenghua Zhao
    JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES 122 (4) 767 - 795 2169-8953 2017/04 [Refereed][Not invited]
    The lack of a standardized database of eddy covariance observations has been an obstacle for data-driven estimation of terrestrial CO2 fluxes in Asia. In this study, we developed such a standardized database using 54 sites from various databases by applying consistent postprocessing for data-driven estimation of gross primary productivity (GPP) and net ecosystem CO2 exchange (NEE). Data-driven estimation was conducted by using a machine learning algorithm: support vector regression (SVR), with remote sensing data for 2000 to 2015 period. Site-level evaluation of the estimated CO2 fluxes shows that although performance varies in different vegetation and climate classifications, GPP and NEE at 8days are reproduced (e.g., r(2)=0.73 and 0.42 for 8day GPP and NEE). Evaluation of spatially estimated GPP with Global Ozone Monitoring Experiment 2 sensor-based Sun-induced chlorophyll fluorescence shows that monthly GPP variations at subcontinental scale were reproduced by SVR (r(2)=1.00, 0.94, 0.91, and 0.89 for Siberia, East Asia, South Asia, and Southeast Asia, respectively). Evaluation of spatially estimated NEE with net atmosphere-land CO2 fluxes of Greenhouse Gases Observing Satellite (GOSAT) Level 4A product shows that monthly variations of these data were consistent in Siberia and East Asia; meanwhile, inconsistency was found in South Asia and Southeast Asia. Furthermore, differences in the land CO2 fluxes from SVR-NEE and GOSAT Level 4A were partially explained by accounting for the differences in the definition of land CO2 fluxes. These data-driven estimates can provide a new opportunity to assess CO2 fluxes in Asia and evaluate and constrain terrestrial ecosystem models.
  • Hirokazu Toju, Osamu Kishida, Noboru Katayama, Kentaro Takagi
    PLOS ONE 11 (11) 1932-6203 2016/11 [Refereed][Not invited]
    Fungi in soil play pivotal roles in nutrient cycling, pest controls, and plant community succession in terrestrial ecosystems. Despite the ecosystem functions provided by soil fungi, our knowledge of the assembly processes of belowground fungi has been limited. In particular, we still have limited knowledge of how diverse functional groups of fungi interact with each other in facilitative and competitive ways in soil. Based on the high-throughput sequencing data of fungi in a cool-temperate forest in northern Japan, we analyzed how taxonomically and functionally diverse fungi showed correlated fine-scale distributions in soil. By uncovering pairs of fungi that frequently co-occurred in the same soil samples, networks depicting fine-scale co-occurrences of fungi were inferred at the O (organic matter) and A (surface soil) horizons. The results then led to the working hypothesis that mycorrhizal, endophytic, saprotrophic, and pathogenic fungi could form compartmentalized (modular) networks of facilitative, antagonistic, and/or competitive interactions in belowground ecosystems. Overall, this study provides a research basis for further understanding how interspecific interactions, along with sharing of niches among fungi, drive the dynamics of poorly explored biospheres in soil.
  • Yoko Watanabe, Keita Wakabayashi, Satoshi Kitaoka, Takami Satomura, Norikazu Eguchi, Makoto Watanabe, Satoshi Nakaba, Kentaro Takagi, Yuzou Sano, Ryo Funada, Takayoshi Koike
    TREES-STRUCTURE AND FUNCTION 30 (5) 1569 - 1579 0931-1890 2016/10 [Refereed][Not invited]
    Elevated CO (2) concentration affected biomass partitioning in above-ground biomass, but size and number of water-conducting cells were unchanged in Larix kaempferi, Kalopanax septemlobus and Betula platyphylla.Using a Free-Air CO2 Enrichment (FACE) system, we studied the effect of elevated CO2 on the growth, leaf gas exchange and xylem anatomy of a conifer, Larix kaempferi, and two angiospermous tree species, Kalopanax septemlobus and Betula platyphylla. Two-year-old seedlings were grown at control sites (ambient; 370 ppm) and FACE sites (elevated; 500 ppm) for 5 years. We measured the lumen area and number of water-conducting cells, as well as biomass and leaf gas exchange, and visualized the functional region of water transport using a dye injection experiment. Elevated CO2 did not induce any significant changes in growth or in leaf gas exchange or lumen area of earlywood tracheids in L. kaempferi relative to ambient CO2. In two other tree species, elevated CO2 was found to enhance tree height and total leaf area (LA), with no change in stomatal conductance. In K. septemlobus, there were no changes in lumen area or number of earlywood vessels, or in the functional region of water transport. B. platyphylla also underwent no changes in lumen area or number of vessels, although there was a yearly variation in the size of the vessels. Our results show that 5 years of CO2 exposure did not notably affect the anatomical features of water-conducting cells. This finding suggests that, under elevated CO2, trees respond to changes in water balance due to changes in LA by extending the hydraulically active area of xylem.
  • M. Watanabe, S. Kitaoka, N. Eguchi, Y. Watanabe, T. Satomura, K. Takagi, F. Satoh, T. Koike
    PLANT BIOLOGY 18 56 - 62 1435-8603 2016/01 [Refereed][Not invited]
    The purpose of this study was to obtain basic information on acclimation capacity of photosynthesis in Siebold's beech seedlings to increasing light intensity under future elevated CO2 conditions. We monitored leaf photosynthetic traits of these seedlings in changing light conditions (before removal of shade trees, the year after removal of shade trees and after acclimation to open conditions) in a 10-year free air CO2 enrichment experiment in northern Japan. Elevated CO2 did not affect photosynthetic traits such as leaf mass per area, nitrogen content and biochemical photosynthetic capacity of chloroplasts (i.e. maximum rate of carboxylation and maximum rate of electron transport) before removal of the shade trees and after acclimation to open conditions; in fact, a higher net photosynthetic rate was maintained under elevated CO2. However, in the year after removal of the shade trees, there was no increase in photosynthesis rate under elevated CO2 conditions. This was not due to photoinhibition. In ambient CO2 conditions, leaf mass per area and nitrogen content were higher in the year after removal of shade trees than before, whereas there was no increase under elevated CO2 conditions. These results indicate that elevated CO2 delays the acclimation of photosynthetic traits of Siebold's beech seedlings to increasing light intensity.
  • Noboru Katayama, Osamu Kishida, Rei Sakai, Shintaro Hayakashi, Chikako Miyoshi, Kinya Ito, Aiko Naniwa, Aya Yamaguchi, Katsunori Wada, Shiro Kowata, Yoshinobu Koike, Katsuhiro Tsubakimoto, Kenichi Ohiwa, Hirokazu Sato, Toru Miyazaki, Shinichi Oiwa, Tsubasa Oka, Shinya Kikuchi, Chikako Igarashi, Shiho Chiba, Yoko Akiyama, Hiroyuki Takahashi, Kentaro Takagi
    PLOS ONE 10 (12) 1932-6203 2015/12 [Refereed][Not invited]
    Wild edible plants, ecological foodstuffs obtained from forest ecosystems, grow in natural fields, and their productivity depends on their response to harvesting by humans. Addressing exactly how wild edible plants respond to harvesting is critical because this knowledge will provide insights into how to obtain effective and sustainable ecosystem services from these plants. We focused on bamboo shoots of Sasa kurilensis, a popular wild edible plant in Japan. We examined the effects of harvesting on bamboo shoot productivity by conducting an experimental manipulation of bamboo shoot harvesting. Twenty experimental plots were prepared in the Teshio Experimental Forest of Hokkaido University and were assigned into two groups: a harvest treatment, in which newly emerged edible bamboo shoots were harvested (n = 10); and a control treatment, in which bamboo shoots were maintained without harvesting (n = 10). In the first year of harvesting (2013), bamboo shoot productivities were examined twice; i.e., the productivity one day after harvesting and the subsequent post-harvest productivity (2-46 days after harvesting), and we observed no difference in productivity between treatments. This means that there was no difference in original bamboo shoot productivity between treatments, and that harvesting did not influence productivity in the initial year. In contrast, in the following year (2014), the number of bamboo shoots in the harvested plots was 2.4-fold greater than in the control plots. These results indicate that over-compensatory growth occurred in the harvested plots in the year following harvesting. Whereas previous research has emphasized the negative impact of harvesting, this study provides the first experimental evidence that harvesting can enhance the productivity of a wild edible plant. This suggests that exploiting compensatory growth, which really amounts to less of a decline in productivity, may be s a key for the effective use of wild edible plants.
  • Takayoshi Koike, Makoto Watanabe, Yoko Watanabe, Evgenios Agathokleous, Norikazu Eguchi, Kentaro Takagi, Fuyuki Satoh, Satoshi Kitaoka, Ryo Funada
    JOURNAL OF AGRICULTURAL METEOROLOGY 71 (3) 174 - 184 0021-8588 2015/09 [Refereed][Not invited]
    We examined the effects of elevated CO2 (eCO(2)) on the growth and photosynthetic responses of deciduous trees using a Free Air CO2 Enrichment (FACE). In the FACE, photosynthesis was down-regulated in several trees but not in alder. Except alder, the leaf nitrogen concentration decreased in eCO(2). Alder underwent symbiosis with N-fixing microorganisms (Frankia sp.) in roots, which act as a sink of photosynthates. Leaves of alder had intensively been grazed by leaf beetles in eCO(2), due to the enhanced leaf N concentration; grazed leaves died later. The leaf area index was initially increased by eCO(2), but this increment minimized over time, as it was found in other FACE systems in global. The light compensation point of the light-photosynthetic curves declined, with an increase in the initial slope of the curve. In eCO(2), the stomatal conductance of most species decreased and the photosynthetic water use efficiency (PWUE) increased. We expected the eCO(2)-induced increase in the PWUE being accompanied by smaller size and density of the vessels. However, in eCO(2), the vessel size of petioles and current shoots decreased without evident anatomical changes. We conclude that the whole plant physiology must be studied in order to provide insight into further changes.
  • Karibu Fukuzawa, Hideaki Shibata, Kentaro Takagi, Fuyuki Satoh, Takayoshi Koike, Kaichiro Sasa
    PLANT SPECIES BIOLOGY 30 (2) 104 - 115 0913-557X 2015/04 [Refereed][Not invited]
    To clarify the role of dense understory vegetation in the stand structure, and in carbon (C) and nitrogen (N) dynamics of forest ecosystems with various conditions of overstory trees, we: (i) quantified the above- and below-ground biomasses of understory dwarf bamboo (Sasa senanensis) at the old canopy-gap area and the closed-canopy area and compared the stand-level biomasses of S.senanensis with that of overstory trees; (ii) determined the N leaching, soil respiration rates, fine-root dynamics, plant area index (PAI) of S. senanensis, and soil temperature and moisture at the tree-cut patches (cut) and the intact closed-canopy patches (control). The biomass of S. senanensis in the canopy-gap area was twice that at the closed-canopy area. It equated to 12% of total biomass above ground but 41% below ground in the stand. The concentrations of NO3- and NH4+ in the soil solution and soil respiration rates did not significantly change between cut and control plots, indicating that gap creation did not affect the C or N dynamics in the soil. Root-length density and PAI of S. senanensis were significantly greater at the cut plots, suggesting the promotion of S. senanensis growth following tree cutting. The levels of soil temperature and soil moisture were not changed following tree cutting. These results show that S. senanensis is a key component species in this cool-temperate forest ecosystem and plays significant roles in mitigating the loss of N and C from the soil following tree cutting by increasing its leaf and root biomass and stabilizing the soil environment.
  • Kentaro Takagi, Yasumichi Yone, Hiroyuki Takahashi, Rei Sakai, Hajime Hojyo, Tatsuya Kamiura, Mutsumi Nomura, Naishen Liang, Tatsuya Fukazawa, Hisashi Miya, Toshiya Yoshida, Kaichiro Sasa, Yasumi Fujinuma, Takeshi Murayama, Hiroyuki Oguma
    ECOLOGICAL INFORMATICS 26 54 - 60 1574-9541 2015/03 [Refereed][Not invited]
    Trees are recognized as a carbon reservoir, and precise and convenient methods for forest biomass estimation are required for adequate carbon management Airborne light detection and ranging (LiDAR) is considered to be one of the solutions for large-scale forest biomass evaluation. To clarify the relationship between mean canopy height determined by airborne LiDAR and forest timber volume and biomass of cool-temperate forests in northern Hokkaido, Japan, we conducted LiDAR observations covering the total area of the Teshio Experimental Forest (225 km(2)) of Hokkaido University and compared the results with ground surveys and previous studies. Timber volume and aboveground tree carbon content of the studied forest stands ranged from 101.43 to 480.40 m(3) ha(-1) and from 30.78 to 180.54 MgC ha-1, respectively. The LiDAR mean canopy height explained the variation among stands well (volume: r(2) = 0.80, RMSE = 55.04 m(3) ha(-1); aboveground tree carbon content: = 0.78, RMSE = 19.10 MgC ha(-1)) when one simple linear regression equation was used for all types (hardwood, coniferous, and mixed) of forest stands. The determination of a regression equation for each forest type did not improve the prediction power for hardwood (volume: r(2) = 0.84, RMSE = 62.66 m(3) ha(-1); aboveground tree carbon content: r(2) = 0.76, RMSE = 27.05 MgC ha(-1)) or coniferous forests (volume: r(2) = 0.75, RMSE = 51.07 m(3) ha(-1); aboveground tree carbon content: r(2) = 0.58, RMSE = 19.00 MgC ha(-1)). Thus, the combined regression equation that includes three forest types appears to be adequate for practical application to large-scale forest biomass estimation. (C) 2015 Elsevier B.V. All rights reserved.
  • Falster Daniel S, Duursma Remko A, Ishihara Masae I, Barneche Diego R, FitzJohn Richard G, Vårhammar Angelica, Aiba Masahiro, Ando Makoto, Anten Niels, Aspinwall Michael J, Baltzer Jennifer L, Baraloto Christopher, Battaglia Michael, Battles John J, Bond-Lamberty Ben, van Breugel Michiel, Camac James, Claveau Yves, Coll Lluís, Dannoura Masako, Delagrange Sylvain, Domec Jean-Christophe, Fatemi Farrah, Feng Wang, Gargaglione Veronica, Goto Yoshiaki, Hagihara Akio, Hall Jefferson S, Hamilton Steve, Harja Degi, Hiura Tsutom, Holdaway Robert, Hutley Lindsay S, Ichie Tomoaki, Jokela Eric J, Kantola Anu, Kelly Jeff W. G, Kenzo Tanaka, King David, Kloeppel Brian D, Kohyama Takashi, Komiyama Akira, Laclau Jean-Paul, Lusk Christopher H, Maguire Douglas A, le Maire Guerric, Mäkelä Annikki, Markesteijn Lars, Marshall John, McCulloh Katherine, Miyata Itsuo, Mokany Karel, Mori Shigeta, Myster Randall W, Nagano Masahiro, Naidu Shawna L, Nouvellon Yann, O'Grady Anthony P, O'Hara Kevin L, Ohtsuka Toshiyuki, Osada Noriyuki, Osunkoya Olusegun O, Peri Pablo Luis, Petritan Any Mary, Poorter Lourens, Portsmuth Angelika, Potvin Catherine, Ransijn Johannes, Reid Douglas, Ribeiro Sabina C, Roberts Scott D, Rodríguez Rolando, Saldaña-Acosta Angela, Santa-Regina Ignacio, Sasa Kaichiro, Selaya N. Galia, Sillett Stephen C, Sterck Frank, Takagi Kentaro, Tange Takeshi, Tanouchi Hiroyuki, Tissue David, Umehara Toru, Utsugi Hajime, Vadeboncoeur Matthew A, Valladares Fernando, Vanninen Petteri, Wang Jian R, Wenk Elizabeth, Williams Richard, de Aquino, Ximenes Fabiano, Yamaba Atsushi, Yamada Toshihiro, Yamakura Takuo, Yanai Ruth D, York Robert A
    Ecology Ecological Society of America 96 (5) 1445  2015 [Refereed][Not invited]
  • Kentaro Takagi, Ryuichi Hirata, Reiko Ide, Masahito Ueyama, Kazuhito Ichii, Nobuko Saigusa, Takashi Hirano, Jun Asanuma, Sheng-Gong Li, Takashi Machimura, Yuichiro Nakai, Takeshi Ohta, Yoshiyuki Takahashi
    SOIL SCIENCE AND PLANT NUTRITION 61 (1) 61 - 75 0038-0768 2015/01 [Refereed][Not invited]
    Larch (Larix spp.) forests are predominantly distributed across high latitudes of Eurasia. They potentially have a strong influence on the terrestrial carbon and energy cycles, because of their vast area and the large carbon stocks in their peat soils in the permafrost. In this study, we elucidated intersite variation of ecosystem photosynthetic and respiratory parameters of eight larch forests in East Asia using the CarboEastAsia carbon flux and micrometeorology dataset. These parameters were determined using the empirical relationship between the carbon fluxes (photosynthesis and respiration) and micrometeorological variables (light and temperature). In addition, we examined leaf area index (LAI) determined by Moderate Resolution Imaging Spectroradiometer (MODIS) remote sensing data to explain the intersite variation. Linear or exponential relationships with annual mean temperature or seasonal maximum LAI at the study sites were found for the annual carbon fluxes (gross primary production [GPP] and total ecosystem respiration [RE]) as well as for four of the five seasonal maximum values of determined photosynthetic and respiratory parameters (maximum GPP at light saturation, initial slope of the light-response curve, daytime respiration, and RE at the reference temperature of 10 degrees C). Phenological indices, such as start day of the growing season, growing season length and growing season degree days explained much of the intersite variation of GPP and RE of the studied larch forests; however, the relationship between MODIS LAI and photosynthetic or respiratory parameters implies that the intersite variation in GPP and RE was caused not only by the temperature variation (abiotic factor), but also by the variation in the photosynthetic and respiration activity by vegetation (biotic factor) through the change in leaf (or whole vegetation) biomass. Our analysis shows that MODIS LAI serves as a good index to explain the variation of the ecosystem photosynthetic and respiratory characteristics of East Asian larch forests.
  • Maricar Aguilos, Kentaro Takagi, Naishen Liang, Masahito Ueyama, Karibu Fukuzawa, Mutsumi Nomura, Osamu Kishida, Tatsuya Fukazawa, Hiroyuki Takahashi, Chikara Kotsuka, Rei Sakai, Kinya Ito, Yoko Watanabe, Yasumi Fujinuma, Yoshiyuki Takahashi, Takeshi Murayama, Nobuko Saigusa, Kaichiro Sasa
    AGRICULTURAL AND FOREST METEOROLOGY 197 26 - 39 0168-1923 2014/10 [Refereed][Not invited]
    A mixed forest in northern Japan, which had been a weak carbon sink (net ecosystem CO2 exchange [NEE] = -0.44 +/- 0.5 Mg C ha(-1) yr(-1)), was disturbed by clear-cutting in 2003 and was replaced with a hybrid larch (Larix gmelinii x L. kaempferi) plantation in the same year. To evaluate the impact of the clear-cutting on the ecosystem's carbon budget, we used 10.5 years (2001-2011) of eddy covariance measurements of CO2 fluxes and the biomass observation for each ecosystem component. BIOME-BGC model was applied to simulate the changes in the carbon fluxes and stocks caused by the clear-cutting. After clear-cutting in 2003, the ecosystem abruptly became a large carbon source. The total CO2 emission during the first 3 years after the disturbance (2003-2005) was 12.2 +/- (0.9-1.5; possible min-max range of the error) Mg C ha(-1), yet gradually decreased to 2.5 +/- (1-2) Mg C ha(-1) during the next 4 years. By 2010, the ecosystem had regained its status as a carbon sink (NEE = -0.49 +/- 0.5 Mg C ha(-1) yr(-1)). Total gross primary production, ecosystem respiration, and NEE during the 7 years after the clear-cutting (2003-2009) were 64.5 +/- (2.6-7), 79.2 +/- (2.6-7), and 14.7 +/- (1.3-3.5) Mg C ha(-1), respectively. From 2003 to 2009, the understory Sasa biomass increased by 16.3 +/- 4.8 Mg C ha(-1), whereas the newly planted larch only gained 1.00 +/- 0.02 Mg C ha(-1). The BIOME-BGC simulated observed carbon fluxes and stocks, although further modification on the parameter set may be needed according with the tree growth and corresponding suppression of Sasa growth. Ecosystem carbon budget evaluation and the model simulation suggested that the litter including harvest residues became a large carbon emitter (similar to 31.9 Mg C ha(-1)) during the same period. Based on the cumulative NEE during the period when the forest was a net carbon source, we estimate that the ecosystem will require another 8-34 years to fully recover all of the CO2 that was emitted after the clear-cutting, if off-site carbon storage in forest products is not considered. (C) 2014 Elsevier B.V. All rights reserved.
  • Makoto Watanabe, Satoshi Kitaoka, Norikazu Eguchi, Yoko Watanabe, Takami Satomura, Kentaro Takagi, Fuyuki Satoh, Takayoshi Koike
    EUROPEAN JOURNAL OF FOREST RESEARCH 133 (4) 725 - 733 1612-4669 2014/07 [Refereed][Not invited]
    To predict the performance of coppice forests with Japanese oak (Quercus mongolica var. crispula) in future changing environment, we studied the growth, photosynthesis, and powdery mildew (Erysiphe alphitoides) infection of sprouts of Japanese oak under free-air CO2 enrichment. Elevated CO2 reduced powdery mildew infection in both leaves of the shoot emerged in spring (1st flush) and the lammas and proleptic shoots (2nd flush) of sprouts. We observed significant increase in the net photosynthetic rate at growth CO2 concentration (i.e., 370 and 500 mu mol mol(-1) for ambient and elevated CO2 treatments, respectively) in both 1st and 2nd flush leaves of sprouts grown under elevated CO2. On the other hand, no significant increase in net photosynthetic rate under elevated CO2 was found before cutting. The photosynthetic activity of 2nd flush leaves in the sprouts under ambient condition was greatly reduced by severe infection to powdery mildew. Growth of sprouts was enhanced in the elevated CO2 condition. We conclude the growth enhancement in Japanese oak sprouts under elevated CO2 in the present study was achieved not only by physiological response (i.e., photosynthetic stimulation) but also by disease interaction.
  • 対流圏オゾンの森林への影響評価に関する研究概要: 札幌実験苗畑の例
    小池孝良, 渡辺 誠, 星加康智, 玉井 裕, 高木 健太郎, 市川 一, 門松昌彦, 佐藤冬樹
    北方森林保全技術 32 32 - 34 2014/03 [Not refereed][Not invited]
  • Xianglan Li, Shunlin Liang, Wenping Yuan, Guirui Yu, Xiao Cheng, Yang Chen, Tianbao Zhao, Jinming Feng, Zhuguo Ma, Mingguo Ma, Shaomin Liu, Jiquan Chen, Changliang Shao, Shenggong Li, Xudong Zhang, Zhiqiang Zhang, Ge Sun, Shiping Chen, Takeshi Ohta, Andrej Varlagin, Akira Miyata, Kentaro Takagi, Nobuko Saiqusa, Tomomichi Kato
    ECOHYDROLOGY 7 (1) 139 - 149 1936-0584 2014/02 [Refereed][Not invited]
    Quantifying regional evapotranspiration (ET) and environmental constraints are particularly important for understanding water and carbon cycles of terrestrial ecosystems. However, a large uncertainty in the regional estimation of ET still remains for the terrestrial ecosystems in China. This study used ET measurements of 34 eddy covariance sites within China and adjacent regions to examine the performance of the revised Remote Sensing-Penman Monteith (RS-PM) model over various ecosystem types including forests, grasslands, wetlands and croplands. No significant systematic error was found in the revised RS-PM model predictions, which explained 61% of the ET variations at all of the validation sites. Regional patterns of ET at a spatial resolution of 10x10km were quantified using a meteorology dataset from 753 meteorological stations, Modern Era Retrospective-analysis for Research and Applications (MERRA) reanalysis products and satellite data such as the Advanced Very High Resolution Radiometer (AVHRR) leaf area index. ET decreased from the southeast of China toward the northwest. Relatively high ET values were found in the southern China such as Yunnan, Hainan, Fujian and Guangdong Provinces, whereas low ET values occurred in northwestern China such as in the Xinjiang autonomous region. On average, the annual ET presented an increasing trend during the 1982-2009, with relatively low ET in 1985, 1993, 1997, 2000 and 2009. We found that the mean annual ET was higher than world average, ranging spatially between 484 and 521 mm yr(-1), with a mean value of 500 mm yr(-1), which accounted for approximately 56-83% of the world's total land-surface ET. Copyright (c) 2012 John Wiley & Sons, Ltd.
  • J. Hong, K. Takagi, T. Ohta, Y. Kodama
    HYDROLOGICAL PROCESSES 28 (1) 37 - 42 0885-6087 2014/01 [Refereed][Not invited]
    During the Asian monsoon period, intense precipitation commonly occurs for an extended period in accompaniment with a reduction in solar radiation. This suggests that wet surface evapotranspiration is an important contributor to the total evapotranspiration. Therefore, investigating evapotranspiration over a wet canopy surface is critical to achieve a better understanding of water and energy cycles in Asia. In this study, we estimated surface resistances under wet conditions in a mixed forest influenced by the East Asian monsoon system. We showed that the surface resistance had a non-negligible magnitude of about 30 sm(-1) even under wet conditions. We also found that the ratio between the actual and potential evapotranspiration depended on the friction velocity regardless of the time of day. Our analyses suggest that this dependency is tightly related to the underestimation of turbulent fluxes by the eddy-covariance system under wet surface conditions. Together, our findings suggest that the wet surface resistance, although small, should be considered in simulating evapotranspiration because the forest ecosystem is strongly coupled to the overlying atmosphere. This could significantly improve the shortcomings of evapotranspiration measurement and modeling in Asian forest canopies influenced by the monsoon system. Copyright (c) 2012 John Wiley & Sons, Ltd.
  • R. Hirata, K. Takagi, A. Ito, T. Hirano, N. Saigusa
    BIOGEOSCIENCES 11 (18) 5139 - 5154 1726-4170 2014 [Refereed][Not invited]
    We evaluated the long-term (52-year) effect of climate, disturbance, and subsequent recovery on the carbon balance of cool temperate forests by using the process-based ecosystem model VISIT. The study sites were artificial larch forests planted after clear-cutting of mixed forest in Hokkaido, Japan. The model was validated, scenarios were computed, and a sensitivity analysis was performed. First, we performed a baseline simulation of carbon dynamics and compared these values with those observed across a wide range of stand ages (old mixed forest and young and middle-aged larch forests). Second, we ran scenarios to investigate how disturbance and several climate factors affect long-term carbon fluxes. Third, we analyzed the sensitivity of carbon balance to the amount of disturbance-generated tree biomass residues. By taking into account seasonal variation in the understory leaf area index, which played an important role, especially in the initial stage of recovery, the simulated net ecosystem production (NEP), gross primary production, ecosystem respiration, and biomass for the three types of forest were consistent with observed values (mean +/- SD of R-2 of monthly NEP, GPP and RE for the three types of forest were 0.63 +/- 0.26, 0.93 +/- 0.07, 0.94 +/- 0.2, respectively). The effect of disturbances such as clear-cutting, land-use conversion, and thinning on the long-term trend of NEP was larger than that of climate variation, even 50 years after clear-cutting. In contrast, interannual variation in the carbon balance was primarily driven by climate variation. These findings indicate that disturbance controlled the long-term trend of the carbon balance, whereas climate factors controlled yearly variation in the carbon balance. Among the meteorological factors considered, temperature and precipitation were the main ones that affected NEP and its interannual variation. The carbon balance in the initial post-disturbance period, which is strongly affected by the amount of residues, influenced the subsequent long-term carbon budget, implying the importance of residue management. Consequently, carbon release just after disturbance and the length of the recovery period required to balance the carbon budget are controlled by the amount of residues.
  • U. Tsunogai, D. D. Komatsu, T. Ohyama, A. Suzuki, F. Nakagawa, I. Noguchi, K. Takagi, M. Nomura, K. Fukuzawa, H. Shibata
    BIOGEOSCIENCES 11 (19) 5411 - 5424 1726-4170 2014 [Refereed][Not invited]
    Temporal variations in the stable isotopic compositions of nitrate dissolved in stream water eluted from a cool-temperate forested watershed (8 ha) were measured to quantify the biogeochemical effects of clear-cutting of trees and subsequent strip-cutting of the understory vegetation, dwarf bamboo (Sasa senanensis), with special emphasis on changes in the fate of atmospheric nitrate that had been deposited onto the watershed based on Delta O-17 values of nitrate. A significant increase in stream nitrate concentration to 15 mu mol L-1 in spring of 2004 was correlated with a significant increase in the Delta O-17 values of nitrate. Additionally, the high Delta O-17 values of +14.3 parts per thousand suggest that the direct drainage of atmospheric nitrate accounted for more than 50% of total nitrate exported from the forested watershed peaking in spring. Similar increases in both concentrations and Delta O-17 values were also found in spring of 2005. Conversely, low Delta O-17 values less than +1.5% were observed in other seasons, regardless of increases in stream nitrate concentration, indicating that the majority of nitrate exported from the forested watershed during seasons other than spring was remineralized nitrate: those retained in the forested ecosystem as either organic N or ammonium and then been converted to nitrate via microbial nitrification. When compared with the values prior to strip-cutting, the annual export of atmospheric nitrate and remineralized nitrate increased more than 16-fold and fourfold, respectively, in 2004, and more than 13-fold and fivefold, respectively, in 2005. The understory vegetation (Sasa) was particularly important to enhancing biological consumption of atmospheric nitrate.
  • Karibu Fukuzawa, Hideaki Shibata, Kentaro Takagi, Fuyuki Satoh, Takayoshi Koike, Kaichiro Sasa
    FOREST ECOLOGY AND MANAGEMENT 310 700 - 710 0378-1127 2013/12 [Refereed][Not invited]
    To understand the temporal pattern of fine-root dynamics and the factors that affect it, we investigated the seasonal and interannual variation in fine-root production (FRP) and fine-root mortality (FRM) rates, as well as fine-root biomass (FRB) and necromass in a cool temperate forest in northern Japan that was covered with dense understory vegetation of Sasa senanensis. We measured the root length density (RLD) and the rate of root production and mortality over 3 yr using minirhizotrons, and compared these rates with temperature, precipitation, soil moisture, and plant area indices (PAI). We also measured the FRB and the necromass of fine roots four times per year for 2 yr using soil cores and calculated dry weight-based FRP and FRM. FRB in the uppermost 15 cm of the surface-soil layer accounted for 41-61% of the biomass up to 60 cm soil depth, and decreased with increasing soil depth. The biomass of fine roots with root diameters <0.5 mm was almost equivalent to that of roots measuring 0.5-2 mm in diameter. Sasa roots accounted for 59-88% of the total FRB. FRB did not fluctuate seasonally, whereas RLD did. The FRP rate was high in mid- to late summer and correlated significantly with air and soil temperatures, indicating that temperature affects FRP. However, the relationship between FRP and soil moisture was weak. FRP was significantly correlated with the PAI of oak trees and the increment in the PAI of Sasa, suggesting that endogenous factors also affect FRP. Depending on the method used to calculate turnover, mean FRP for the 3-year study period was 589 or 726 g m(2) yr(-1), accounting for 36% or 41% of forest net primary production, respectively. The results of this study illustrate the substantial seasonal and interannual fluctuations in FRP, and indicate that a significant proportion of assimilated carbon was allocated to below-ground root systems in an oak-Sasa stand. (C) 2013 Elsevier B.V. All rights reserved.
  • Makoto Watanabe, Qiaozhi Mao, Eka Novriyanti, Kazuhito Kita, Kentaro Takagi, Fuyuki Satoh, Takayoshi Koike
    TREES-STRUCTURE AND FUNCTION 27 (6) 1647 - 1655 0931-1890 2013/12 [Refereed][Not invited]
    Elevated CO (2) enhances the photosynthesis and growth of hybrid larch F (1) seedlings. However, elevated CO (2) -induced change of tree shape may have risk to the other environmental stresses.The hybrid larch F-1 (Larix gmelinii var. japonica x L. kaempferi) is one of the most promising species for timber production as well as absorption of atmospheric CO2. To assess the ability of this species in the future high CO2 environment, we investigated the growth and photosynthetic response of hybrid larch F-1 seedlings to elevated CO2 concentration. Three-year-old seedlings of hybrid larch F-1 were grown on fertile brown forest soil or infertile volcanic ash soil, and exposed to 500 mu mol mol(-1) CO2 in a free-air CO2 enrichment system located in northern Japan for two growing seasons. Regardless of soil type, the exposure to elevated CO2 did not affect photosynthetic traits in the first and second growing seasons; a higher net photosynthetic rate was maintained under elevated CO2. Growth of the seedlings under elevated CO2 was greater than that under ambient CO2. We found that elevated CO2 induced a change in the shape of seedlings: small roots, slender-shaped stems and long-shoots. These results suggest that elevated CO2 stimulates the growth of hybrid larch F-1, although the change in tree shape may increase the risk of other stresses, such as strong winds, heavy snow, and nutrient deficiency.
  • Xianglan Li, Shunlin Liang, Guirui Yu, Wenping Yuan, Xiao Cheng, Jiangzhou Xia, Tianbao Zhao, Jinming Feng, Zhuguo Ma, Mingguo Ma, Shaomin Liu, Jiquan Chen, Changliang Shao, Shenggong Li, Xudong Zhang, Zhiqiang Zhang, Shiping Chen, Takeshi Ohta, Andrej Varlagin, Akira Miyata, Kentaro Takagi, Nobuko Saiqusa, Tomomichi Kato
    ECOLOGICAL MODELLING 261 80 - 92 0304-3800 2013/07 [Refereed][Not invited]
    Gross primary production (GPP) is of significant importance for the terrestrial carbon budget and climate change, but large uncertainties in the regional estimation of GPP still remain over the terrestrial ecosystems in China. Eddy covariance (EC) flux towers measure continuous ecosystem-level exchange of carbon dioxide (CO2) and provide a promising way to estimate GPP. We used the measurements from 32 EC sites to examine the performance of a light use efficiency model (i.e., EC-LUE) at various ecosystem types, including 23 sites in China and 9 sites in adjacent areas with the similar climate environments. No significant systematic error was found in the EC-LUE model predictions, which explained 79% and 62% of the GPP variation at the validation sites with C-3 and C-4 vegetation, respectively. Regional patterns of GPP at a spatial resolution of 10 km x 10 km from 2000 to 2009 were determined using the MERRA (Modern Era Retrospective-analysis for Research and Applications) reanalysis dataset and MODIS (MOD-erate resolution Imaging Spectroradiometer). China's terrestrial GPP decreased from southeast toward the northwest, with the highest values occurring over tropical forests areas, and the lowest values in dry regions. The annual GPP of land in China varied between 5.63 Pg C and 6.39 Pg C, with a mean value of 6.04 Pg C, which accounted for 4.90-6.29% of the world's total terrestrial GPP. The GPP densities of most vegetation types in China such as evergreen needleleaf forests, deciduous needleleaf forests, mixed forests, woody savannas, and permanent wetlands were much higher than the respective global GPP densities. However, a high proportion of sparsely vegetated area in China resulted in the overall low GPP. The inter-annual variability in GPP was significantly influenced by air temperature (R-2 = 0.66, P < 0.05), precipitation (R-2 = 0.71, P < 0.05), and normalized difference vegetation index (NDVI) (R-2 = 0.83, P < 0.05), respectively. Published by Elsevier B.V.
  • Nobuko Saigusa, Sheng-Gong Li, Hyojung Kwon, Kentaro Takagi, Lei-Ming Zhang, Reiko Ide, Masahito Ueyama, Jun Asanuma, Young-Jean Choi, Jung Hwa Chun, Shi-Jie Han, Takashi Hirano, Ryuichi Hirata, Minseok Kang, Tomomichi Kato, Joon Kim, Ying-Nian Li, Takahisa Maeda, Akira Miyata, Yasuko Mizoguchi, Shohei Murayama, Yuichiro Nakai, Takeshi Ohta, Taku M. Saitoh, Hui-Ming Wang, Gui-Rui Yu, Yi-Ping Zhang, Feng-Hua Zhao
    JOURNAL OF FOREST RESEARCH 18 (1) 41 - 48 1341-6979 2013/02 [Refereed][Not invited]
    The datasets of net ecosystem CO2 exchange (NEE) were acquired from 21 forests, 3 grasslands, and 3 croplands in the eastern part of Asia based on the eddy covariance measurements of the international joint program, CarboEastAsia. The program was conducted by three networks in Asia, ChinaFLUX, JapanFlux, and KoFlux, to quantify, synthesize, and understand the carbon budget of the eastern part of Asia. An intercomparison was conducted for NEE estimated by three gap-filling procedures adopted by ChinaFLUX, JapanFlux, and KoFlux to test the range of uncertainty in the estimation of NEE. The overall comparison indicated good agreement among the procedures in the seasonal patterns of NEE, although a bias was observed in dormant seasons depending on the different criteria of data screening. Based on the gap-filled datasets, the magnitude and seasonality of the carbon budget were compared among various biome types, phenology, and stress conditions throughout Asia. The annual values of gross primary production and ecosystem respiration were almost proportional to the annual air temperature. Forest management, including clear-cutting, plantation, and artificial drainage, was significant and obviously affected the annual carbon uptake within the forests. Agricultural management resulted in notable seasonal patterns in the crop sites. The dataset obtained from a variety of biome types would be an essential source of knowledge for ecosystem science as well as a valuable validation dataset for modeling and remote sensing to upscale the carbon budget estimations in Asia.
  • Kazuhito Ichii, Masayuki Kondo, Young-Hee Lee, Shao-Qiang Wang, Joon Kim, Masahito Ueyama, Hee-Jeong Lim, Hao Shi, Takashi Suzuki, Akihiko Ito, Hyojung Kwon, Weimin Ju, Mei Huang, Takahiro Sasai, Jun Asanuma, Shijie Han, Takashi Hirano, Ryuichi Hirata, Tomomichi Kato, Sheng-Gong Li, Ying-Nian Li, Takahisa Maeda, Akira Miyata, Yojiro Matsuura, Shohei Murayama, Yuichiro Nakai, Takeshi Ohta, Taku M. Saitoh, Nobuko Saigusa, Kentaro Takagi, Yan-Hong Tang, Hui-Min Wang, Gui-Rui Yu, Yi-Ping Zhang, Feng-Hua Zhao
    JOURNAL OF FOREST RESEARCH 18 (1) 13 - 20 1341-6979 2013/02 [Refereed][Not invited]
    Based on the model-data comparison at the eddy-covariance observation sites from CarboEastAsia datasets, we report the current status of the terrestrial carbon cycle modeling in monsoon Asia. In order to assess the modeling performance and discuss future requirements for both modeling and observation efforts in Asia, we ran eight terrestrial biosphere models at 24 sites from 1901 to 2010. By analyzing the modeled carbon fluxes against the CarboEastAsia datasets, the strengths and weaknesses of terrestrial biosphere modeling over Asia were evaluated. In terms of pattern and magnitude, the carbon fluxes (i.e., gross primary productivity, ecosystem respiration, and net ecosystem exchange) at the temperate and boreal forest sites were simulated best, whereas the simulation results from the tropical forest, cropland, and disturbed sites were poor. The multi-model ensemble mean values showed lower root mean square errors and higher correlations, suggesting that composition of multiple terrestrial biosphere models would be preferable for terrestrial carbon budget assessments in Asia. These results indicate that the current model-based estimation of terrestrial carbon budget has large uncertainties, and future research should further refine the models to permit re-evaluation of the terrestrial carbon budget.
  • Maricar Aguilos, Kentaro Takagi, Naishen Liang, Yoko Watanabe, Munemasa Teramoto, Seijiro Goto, Yoshiyuki Takahashi, Hitoshi Mukai, Kaichiro Sasa
    TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY 65 1600-0889 2013 [Refereed][Not invited]
    We conducted a soil warming experiment in a cool-temperate forested peatland in northern Japan during the snow-free seasons of 2007-2011, to determine whether the soil warming would change the heterotrophic respiration rate and its temperature sensitivity. We elevated the soil temperature by 3 degrees C at 5-cm depth by using overhead infrared heaters and continuously measured hourly soil CO2 fluxes with a 15-channel automated chamber system. The 15 chambers were divided into three groups each with five replications for the control, unwarmed-trenched and warmed-trenched treatments. Soil warming enhanced heterotrophic respiration by 82% (mean of four seasons (2008-2011) observation +/- SD, 6.84 +/- 2.22 mu mol C m(-2) s(-1)) as compared to the unwarmed-trenched treatment (3.76 +/- 0.98 mu mol C m(-2) s(-1)). The sustained enhancement of heterotrophic respiration with soil warming suggests that global warming will accelerate the loss of carbon substantially more from forested peatlands than from other upland forest soils. Soil warming likewise enhanced temperature sensitivity slightly (Q(10), 3.1 +/- 0.08 and 3.3 +/- 0.06 in the four-season average in unwarmed- and warmed-trenched treatments, respectively), and significant effect was observed in 2009 (p<0.001) and 2010 (p<0.01). However, there was no significant difference in the basal respiration rate at 10 degrees C (R-10, 2.2 +/- 0.52 and 2.8 +/- 1.2 mmol C m(-2) s(-1)) between treatments, although the values tended to be high by warming throughout the study period. These results suggest that global warming will enhance not only the heterotrophic respiration rate itself but also its Q(10) in forests with high substrate availability and without severe water stress, and predictions for such ecosystems obtained by using models assuming no change in Q(10) are likely to underestimate the carbon release from the soil to the atmosphere in a future warmer environment.
  • Aguilos Maricar, Takagi Kentaro, Liang Naishen, Watanabe Yoko, Teramoto Munemasa, Goto Seijiro, Takahashi Yoshiyuki, Mukai Hitoshi, Sasa Kaichiro
    TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY 65 0280-6509 2013 [Refereed][Not invited]
  • Makoto Watanabe, Koharu Ryu, Kazuhito Kita, Kentaro Takagi, Takayoshi Koike
    ENVIRONMENTAL AND EXPERIMENTAL BOTANY 83 73 - 81 0098-8472 2012/11 [Refereed][Not invited]
    We studied the growth and photosynthesis of the hybrid larch F-1 (Larix gmelinii var. japonica x L kaempferi) grown on serpentine soil and the effects of soil N load, to determine the performance of this species as reforestation material in serpentine regions. We prepared 16 experimental plots (2m x 4 m each), eight on serpentine and eight on brown forest soil, and planted one-year-old cutting seedlings of the hybrid larch F-1 in each plot, in May 2007. Ammonium sulfate was supplied to half of the plots of each soil type in 2008 and 2009, at a load of 47 kg N ha(-1) year(-1). Although the growth and photosynthetic capacity of hybrid larch F-1 seedlings in the serpentine soil were limited, the rate of growth in serpentine soil was greater than that of Sakhalin spruce (Picea glehnii) that is dominant species in serpentine regions. There was significant interaction between soil type and N load for the growth and photosynthetic parameters. The N load adversely affected growth and photosynthetic parameters in the serpentine soil, while improved them in brown forest soil. Although the growth rate of hybrid larch F-1 without N loading showed high potential as an afforestation species in serpentine region, increasing deposition of N might be a threat to the growth and photosynthesis of the hybrid larch F-1 in serpentine soil. (C) 2012 Published by Elsevier B.V.
  • Keiji Okada, Naoya Okada, Shinichi Urano, Yui Nishida, Kentaro Takagi, Maricar Aguilos, Taiyo Kobayash
    Journal of Agricultural Meteorology 68 (3) 165 - 174 1881-0136 2012/09/01 [Refereed][Not invited]
    For this study, we conducted nighttime upper-air observations in a complex valley terrain to test the applicability of the atmospheric boundary layer (ABL) method for CO2 flux estimation, comparing the obtained flux with that observed using the eddy covariance technique. Three different definitions for the determination of the nocturnal boundary layer height did not strongly affect the calculation of CO2 flux using the ABL method, which implies that the change in CO2 concentration near the surface strongly affects flux evaluations using the ABL method. The CO2 flux calculated using the ABL method was generally 2-5 times greater than the eddy CO2 flux at < 0.5 m s-1 in the nighttime average horizontal wind velocity, which indicates that the advection from a 2-5 times broader surrounding area caused CO2 accumulation near the surface of the valley bottom, if a slight site-to-site variation in ecosystem respiration within the source area is assumed for the ABL observation. To incorporate advection terms, the equation for the ABL method was modified using the advection factor (AF), where AF was expressed as a linear function of the nighttime average horizontal wind velocity. The modified CO2 flux agreed well with the eddy CO2 flux, but the function of the AF itself is likely to have site-to-site variation. It must be normalized in future studies by consideration of other environmental factors, such as temperature and topographical features. © 2012, The Society of Agricultural Meteorology of Japan. All rights reserved.
  • Maricar M. Aguilos, Kentaro Takagi, Hiroyuki Takahashi, Junko Hasegawa, Daitaro Ashiya, Chikara Kotsuka, Aiko Naniwa, Rei Sakai, Kinya Ito, Chikako Miyoshi, Mutsumi Nomura, Shigeru Uemura, Kaichiro Sasa
    Journal of Agricultural Meteorology 68 (4) 215 - 224 1881-0136 2012/09/01 [Refereed][Not invited]
    We determined the interannual variation of annual litterfall rate in cool-temperate forests [three mixed-forests (Mx1-Mx3), an evergreen coniferous forest (Ec), and a deciduous conifer plantation (Dc)] of northern Hokkaido over a 16-year observation period (1996-2011) and evaluated the effect of meteorological and phenological variables on the annual litterfall production. Total solar radiation during spring (from March to May) positively correlated with the annual litterfall rate in the current year at three mixed forests with statistical significance. A warm spring advanced the day of snow melt and the day of leaf expansion, however, the early leaf expansion did not enhance the annual litter production at any of the studied forests. In conclusion, spring solar radiation was the best explanatory factor among the studied factors that determines the interannual variation of the annual litterfall rate at cool-temperate mixed forests, although the mechanisms behind this relationship remain unknown. The early snowmelt and leaf expansion caused by a warm spring did not directly link to the enhancement of the litterfall rate. This implies that global warming or changing rainfall patterns do not necessarily affect the annual litterfall amount in these forests, at least within the range observed during the 16 years. © 2012, The Society of Agricultural Meteorology of Japan. All rights reserved.
  • K. Makoto, H. Shibata, Y. S. Kim, T. Satomura, K. Takagi, M. Nomura, F. Satoh, T. Koike
    BIOLOGY AND FERTILITY OF SOILS 48 (5) 569 - 577 0178-2762 2012/07 [Refereed][Not invited]
    Ecological function of charcoal has been mainly investigated by adding charcoal to soil, which is not fully adequate to understand in situ the role in fire-prone forest ecosystem. To determine in situ effects of charcoal on ecosystem functions, such as nutrient availability, we conducted an experimental burning in a Japanese white birch forest with dense coverage of dwarf bamboo in the understory with or without removal of charcoal. Ammonium-N in the remaining humus layer increased immediately after the burning, but decreased to the level of unburnt plots within 1 month of the burning. Removal of charcoal had no significant effect on the NH4 (+)-N dynamics. Although burning did not affect NO3 (-)-N dynamics during the sampling period, charcoal removal led to a slight increase in NO3 (-)-N. The available P increased immediately after the burning, but then fell at 1 month after burning. Charcoal inhibited the available P depletion and prolonged the high availability of P. Greater availability of P might be due to the adsorption of phosphate in charcoal pores. Exchangeable Ca and Mg increased gradually; charcoal appeared to extend the period of higher concentration of exchangeable Ca and Mg. Charcoal deriving from fire is a key factor in influencing available nutrient in the humus layer of post-fire forests.
  • Mikko Peltoniemi, Minna Pulkkinen, Pasi Kolari, Remko A. Duursma, Leonardo Montagnani, Sonia Wharton, Fredrik Lagergren, Kentaro Takagi, Hans Verbeeck, Torben Christensen, Timo Vesala, Matthias Falk, Denis Loustau, Annikki Makela
    TREE PHYSIOLOGY 32 (2) 200 - 218 0829-318X 2012/02 [Refereed][Not invited]
    The maximum light use efficiency (LUE = gross primary production (GPP)/absorbed photosynthetic photon flux density (aPPFD)) of plant canopies has been reported to vary spatially and some of this variation has previously been attributed to plant species differences. The canopy nitrogen concentration [N] can potentially explain some of this spatial variation. However, the current paradigm of the N-effect on photosynthesis is largely based on the relationship between photosynthetic capacity (A(max)) and [N], i.e., the effects of [N] on photosynthesis rates appear under high PPFD. A maximum LUE-[N] relationship, if it existed, would influence photosynthesis in the whole range of PPFD. We estimated maximum LUE for 14 eddy-covariance forest sites, examined its [N] dependency and investigated how the [N]-maximum LUE dependency could be incorporated into a GPP model. In the model, maximum LUE corresponds to LUE under optimal environmental conditions before light saturation takes place (the slope of GPP vs. PPFD under low PPFD). Maximum LUE was higher in deciduous/mixed than in coniferous sites, and correlated significantly with canopy mean [N]. Correlations between maximum LUE and canopy [N] existed regardless of daily PPFD, although we expected the correlation to disappear under low PPFD when LUE was also highest. Despite these correlations, including [N] in the model of GPP only marginally decreased the root mean squared error. Our results suggest that maximum LUE correlates linearly with canopy [N], but that a larger body of data is required before we can include this relationship into a GPP model. Gross primary production will therefore positively correlate with [N] already at low PPFD, and not only at high PPFD as is suggested by the prevailing paradigm of leaf-level A(max)-[N] relationships. This finding has consequences for modelling GPP driven by temporal changes or spatial variation in canopy [N].
  • Li Xianglan, Liang Shunlin, Yuan Wenping, Yu Guirui, Cheng Xiao, Chen Yang, Zhao Tianbao, Feng Jinming, Ma Zhuguo, Ma Mingguo, Liu Shaomin, Chen Jiquan, Shao Changliang, Li Shenggong, Zhang Xudong, Zhang Zhiqiang, Sun Ge, Chen Shiping, Ohta Takeshi, Varlagin Andrej, Miyata Akira, Takagi Kentaro, Saiqusa Nobuko, Kato Tomomich
    Ecohydrology n/a  1936-0592 2012 [Refereed][Not invited]
  • Latent heat flux estimation using closed-path and low-frequency water vapor concentration sensors
    TAKAGI Kentaro
    Journal of Agricultural Meteorology, Hokkaido 64 4 - 12 2012 [Refereed][Not invited]
  • Fukazawa Tatsuya, Murao Naoto, Sato Hisashi, Takahashi Masahiro, Akiyama Masayuki, Yamaguchi Takashi, Noguchi Izumi, Takahashi Hiroyuki, Kozuka Chikara, Sakai Rei, Takagi Kentaro, Fujinuma Yasumi, Saigusa Nobuko, Matsuda Kazuhide
    Asian Journal of Atmospheric Environment 6 (4) 281 - 287 2287-1160 2012 [Refereed][Not invited]
    Aerosol concentrations at the CC-Lag site in the Teshio Experimental Forest increased from winter to spring and sometimes showed extremely high values associated with Kosa and/or forest-fire events. The range and mean of the mass concentrations of aerosol chemical species were as follows: total particulate mass, 1.2-29, 5.0 elemental carbon, 0.061-2.2, 0.43 organic carbon, 0.059-3.5, 0.79 and sulfate, 0.12-6.2, 1.8 μg/m3. The total masses of the deposited particles on hybrid larch and on bamboo leaves were approximately 35 and 30 μg/cm2, respectively. The amounts of soil particles on the leaves were 6 μg/cm2 for the upper part of hybrid larch, 2 μg/cm2 for the lower part of hybrid larch, and 1 μg/cm2 for Sasa bamboo leaves. The amounts of deposited black carbon were 2.3 μg/cm2 for the upper part of hybrid larch, 0.6 μg/cm2 for the lower part of hybrid larch, and 0.2 μg/cm2 for Sasa bamboo leaves. Half of the total deposited particular mass was attached on the hybrid larch however, most of the total deposited mass was adhered on the Sasa bamboo leaves. Regardless of the species, there tend to be more deposited particles on the leaves in the upper part than in the lower part, with only a few meters height difference. Comparing the composition of the deposited particles to that of the atmospheric aerosols without any size cut, the fractions of water-soluble material sulfate and sea salt in the deposited aerosols were about one tenth and one hundredth lower than that in the aerosols, respectively. On the basis of the measured concentration and the deposited amount on leaves, the deposition velocity of black carbon was estimated to be approximately 0.5 cm/s.
  • Masahito Ueyama, Ryuichi Hirata, Masayoshi Mano, Ken Hamotani, Yoshinobu Harazono, Takashi Hirano, Akira Miyata, Kentaro Takagi, Yoshiyuki Takahashi
    TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY 64 1600-0889 2012 [Refereed][Not invited]
    Synthesis studies using multiple-site datasets for eddy covariance potentially contain uncertainties originating from the use of different flux calculation options, because the choice of the process for calculating half-hourly fluxes from raw time series data is left to individual researchers. In this study, we quantified the uncertainties associated with different flux calculation methods at seven sites. The differences in the half-hourly fluxes were small, generally of the order less than a few percentiles, but they were substantial for the annual fluxes. After the standardisation under current recommendations in the FLUXNET communities, we estimated the uncertainties in the annual fluxes associated with the flux calculations to be 2.6 +/- 2.7 W m(-2) (the mean 90% +/- confidence interval) for the sensible heat flux, 72 +/- 37 g C m(-2) yr(-1) for net ecosystem exchange (NEE), 12 +/- 6% for evapotranspiration, 12 +/- 6% for gross primary productivity and 16 +/- 10% for ecosystem respiration. The self-heating correction strongly influenced the annual carbon balance (143 +/- 93 g C m(-2) yr(-1)), not only for cold sites but also for warm sites, but did not fully account for differences between the open- and closed-path systems (413 +/- 189 g C m(-2) yr(-1)).
  • Yong Suk Kim, Kobayashi Makoto, Fumiaki Takakai, Hideaki Shibata, Takami Satomura, Kentaro Takagi, Ryusuke Hatano, Takayoshi Koike
    EUROPEAN JOURNAL OF FOREST RESEARCH 130 (6) 1031 - 1044 1612-4669 2011/11 [Refereed][Not invited]
    Forest fires affect both carbon (C) and nitrogen (N) cycling in forest ecosystems, and thereby influence the soil-atmosphere exchange of major greenhouse gases (GHGs): carbon dioxide (CO(2)), methane (CH(4)), and nitrous oxide (N(2)O). To determine changes in the soil GHG fluxes following a forest fire, we arranged a low-intensity surface fire in a white birch forest in northern Japan. We established three treatments, having four replications each: a control plot (CON), a burned plot (BURN), and a plot burned with removal of the resulting charcoal (BURN-CHA). Soil GHG fluxes and various properties of the soil were determined on four or five occasions during a period that spanned two growing seasons. We observed increased concentrations of ammonium-N (NH(4)-N) in BURN and BURN-CHA after the fire, while nitrate-N (NO(3)-N) concentration was only increased in BURN-CHA after the fire. The soil CO(2) flux was significantly higher in CON than in BURN or BURN-CHA, but there was no difference in soil CH(4) uptake between the three treatments. Moreover, the N(2)O flux from BURN-CHA soil was slightly greater than in CON or BURN. In BURN-CHA, the soil N(2)O flux peaked in August, but there was no peak in BURN. We found temporal correlations between soil GHG fluxes and soil variables, e.g. soil temperature or NO(3)-N. Our results suggest that environmental changes following fire, including the increased availability of N and the disappearance of the litter layer, have the potential to change soil GHG fluxes. Fire-produced charcoal could be significant in reducing soil N(2)O flux in temperate forests.
  • Takahiro Sasai, Nobuko Saigusa, Kenlo Nishida Nasahara, Akihiko Ito, Hirofumi Hashimoto, Ramakrishna Nemani, Ryuichi Hirata, Kazuhito Ichii, Kentaro Takagi, Taku M. Saitoh, Takeshi Ohta, Kazutaka Murakami, Yasushi Yamaguchi, Takehisa Oikawa
    REMOTE SENSING OF ENVIRONMENT 115 (7) 1758 - 1771 0034-4257 2011/07 [Refereed][Not invited]
    The terrestrial carbon cycle is strongly affected by natural phenomena, terrain heterogeneity, and human-induced activities that alter carbon exchange via vegetation and soil activities. In order to accurately understand terrestrial carbon cycle mechanisms, it is necessary to estimate spatial and temporal variations in carbon flux and storage using process-based models with the highest possible resolution. We estimated terrestrial carbon fluxes using a biosphere model integrating eco-physiological and mechanistic approaches based on satellite data (BEAMS) and observations with 1-km grid resolution. The study area is the central Far East Asia region, which lies between 30 degrees and 50 degrees north latitude and 125 and 150 east longitude. Aiming to simulate terrestrial carbon exchanges under realistic land surface conditions, we used as many satellite-observation datasets as possible, such as the standard MODIS, TRMM, and SRTM high-level land products. Validated using gross primary productivity (GPP), net ecosystem production (NEP), net radiation and latent heat with ground measurements at six flux sites, the model estimations showed reasonable seasonal and annual patterns. In extensive analysis, the total GPP and NPP were determined to be 2.1 and 0.9 PgC/year, respectively. The total NEP estimation was + 5.6 TgC/year, meaning that the land area played a role as a carbon sink from 2001 to 2006. In analyses of areas with complicated topography, the 1-km grid estimation could prove to be effective in evaluating the effect of landscape on the terrestrial carbon cycle. The method presented here is an appropriate approach for gaining a better understanding of terrestrial carbon exchange, both spatially and temporally. (C) 2011 Elsevier Inc. All rights reserved.
  • Aguilos, M, Takagi, K, Liang, N, Watanabe, Y, Goto, S, Takahashi, Y, Mukai, H, Sasa, K
    Biogeosciences Discussion 8 6415 - 6445 2011 [Refereed][Not invited]
  • Khatun, R, Ohta, T, Kotani, A, Asanuma, J, Gamo, M, Han, S, Hirano, T, Nakai, Y, Saigusa, N, Takagi, K, Wang, H, Yoshifuji, N
    Hydrological Research Letters 5 88 - 92 1882-3416 2011 [Refereed][Not invited]
  • KHATUN Rehana, OHTA Takeshi, KOTANI Ayumi, ASANUMA Jun, GAMO Minoru, HAN Shijie, HIRANO Takashi, NAKAI Yuichiro, SAIGUSA Nobuko, TAKAGI Kentaro, WANG Huimin, YOSHIFUJI Natsuko
    Hydrological Research Letters 5 83 - 87 1882-3416 2011 [Refereed][Not invited]
  • Kim, Y.S, Watanabe, M, Imori, M, Sasa, K, Takagi, K, Hatano, R, Koike, T
    Journal of Japan Society for Atmospheric Environment 46 (1) 30 - 36 1341-4178 2011 [Refereed][Not invited]
  • Ichii K, Suzuki T, Kato T, Ito A, Hajima T, Ueyama M, Sasai T, Hirata R, Saigusa N, Ohtani Y, Takagi K
    Biogeosciences 7 (7) 2061 - 2080 1726-4170 2010 [Refereed][Not invited]
  • Factors controlling soil respiration in a riparian zone in northern Hokkaido
    KATO Sho, OKADA Keiji, TAKAGI Kentaro, URANO Shin-ichi
    Journal of Agricultural Meteorology, Hokkaido 62 11 - 18 2010 [Refereed][Not invited]
  • Izumi Noguchi, Kentaro Hayashi, Takunori Kato, Takashi Yamaguchi, Masayuki Akiyama, Hideyuki Otsuka, Shigekatsu Sakai, Kentaro Takagi, Tatsuya Fukazawa, Hideaki Shibata, Yasumi Fujinuma, Nobuko Saigusa, Minoru Shimotori, Tomomi Endo, Hiroaki Yago, Kazuhide Matsuda, Urumu Tsunogai, Hiroshi Hara
    Journal of Japan Society for Atmospheric Environment 45 (4) 153 - 165 1341-4178 2010 [Refereed][Not invited]
  • Ichii, K, Suzuki, T, Kato, T, Ito, A, Hajima, T, Ueyama, M, Sasai, T, Hirata, R, Saigusa, N, Ohtani, Y, Takagi, K
    Biogeosciences 7 2061 - 2085 2010 [Refereed][Not invited]
  • Allometric relationships and carbon and nitrogen contents for three major tree species (Quercus crispula, Betula ermanii, and Abies sachalinensis) in northern Hokkaido, Japan
    Takagi, K, Kotsuka, C, Fukuzawa, K, Kayama, M, Makoto, K, Watanabe, T, Nomura, M, Fukazawa, T, Takahashi, H, Hojyo, H, Ashiya, D, Naniwa, A, Sugata, S, Kamiura T, Sugishita Y, Sakai, R, Ito, K, Kobayashi, M, Maebayashi, M, Mizuno, M, Murayama, T, Kinoshita, K, Fujiwara, D, Hashida, S, Shibata, H, Yoshida, T, Sasa, K, Saigusa, N, Fujinuma, Y, Akibayashi, Y
    Eurasian Journal of Forest Research 13 1 - 7 2010 [Refereed][Not invited]
  • M. Ueyama, K. Ichii, R. Hirata, K. Takagi, J. Asanuma, T. Machimura, Y. Nakai, T. Ohta, N. Saigusa, Y. Takahashi, T. Hirano
    BIOGEOSCIENCES 7 (3) 959 - 977 1726-4170 2010 [Refereed][Not invited]
    Larch forests are widely distributed across many cool-temperate and boreal regions, and they are expected to play an important role in global carbon and water cycles. Model parameterizations for larch forests still contain large uncertainties owing to a lack of validation. In this study, a process-based terrestrial biosphere model, BIOME-BGC, was tested for larch forests at six AsiaFlux sites and used to identify important environmental factors that affect the carbon and water cycles at both temporal and spatial scales. The model simulation performed with the default deciduous conifer parameters produced results that had large differences from the observed net ecosystem exchange (NEE), gross primary productivity (GPP), ecosystem respiration (RE), and evapotranspiration (ET). Therefore, we adjusted several model parameters in order to reproduce the observed rates of carbon and water cycle processes. This model calibration, performed using the AsiaFlux data, substantially improved the model performance. The simulated annual GPP, RE, NEE, and ET from the calibrated model were highly consistent with observed values. The observed and simulated GPP and RE across the six sites were positively correlated with the annual mean air temperature and annual total precipitation. On the other hand, the simulated carbon budget was partly explained by the stand disturbance history in addition to the climate. The sensitivity study indicated that spring warming enhanced the carbon sink, whereas summer warming decreased it across the larch forests. The summer radiation was the most important factor that controlled the carbon fluxes in the temperate site, but the VPD and water conditions were the limiting factors in the boreal sites. One model parameter, the allocation ratio of carbon between belowground and aboveground, was site-specific, and it was negatively correlated with the annual climate of annual mean air temperature and total precipitation. Although this study substantially improved the model performance, the uncertainties that remained in terms of the sensitivity to water conditions should be examined in ongoing and long-term observations.
  • K. Ryu, M. Watanabe, H. Shibata, K. Takagi, M. Nomura, Takayoshi Koike
    LANDSCAPE AND ECOLOGICAL ENGINEERING 5 (2) 99 - 106 1860-1871 2009/07 [Refereed][Not invited]
    For sustainable use and suitable management of larch plantations, we must clarify the ecophysiological responses of larch species to environmental changes. The physical environment has been changing dramatically, e.g., increase in atmospheric CO(2) concentration ([CO(2)]), nitrogen (N) deposition, and atmospheric ozone concentration ([O(3)]), and these changes may negatively affect growth of larch species. This review summarizes the previous experimental studies on the ecophysiological responses of larch species to elevated [CO(2)], soil acidification, elevated [O(3)], and N load. Based on the advanced studies, although elevated [CO(2)] will stimulate the productivity of larch, increase of [O(3)] and severe soil acidification will reduce it. Increase of N deposition, at least, will not negatively affect larch productivity. Finally, we propose the future direction for investigation to understand the mechanism of the responses of larch species and to predict the associated risk.
  • Kentaro Hayashi, Kentaro Takagi, Izumi Noguchi, Karibu Fukuzawa, Hiroyuki Takahashi, Tatsuya Fukazawa, Hideaki Shibata, Yasumi Fujinuma
    WATER AIR AND SOIL POLLUTION 200 (1-4) 33 - 46 0049-6979 2009/06 [Refereed][Not invited]
    The present study aimed to elucidate the atmosphere-forest exchange of ammoniacal nitrogen (NH(X)-N) at a young larch ecosystem. NH(X)-N exchanges were measured at a remote site in northernmost Japan where 4-year-old larches were growing after a pristine forest had been clear-cut and subsequent dense dwarf bamboo (Sasa) had been strip-cut. The site was a clean area for atmospheric ammonia with mean concentrations of 0.38 and 0.11 mu g N m(-3) in snowless and snow seasons, respectively. However, there was a general net emission of NH(X)-N. The annual estimated emission of NH(X)-N of 4.8 kg N ha(-1) year(-1) exceeded the annual wet deposition of 2.4 kg N ha(-1) year(-1), but the weekly exchange fluxes may have been underestimated by 28-60%. The main cause of the ammonia loss from the young larch ecosystem was probably enhanced nitrogen supply stimulated by the cutting of the pristine forest and Sasa, in particular, the Sasa.
  • Kentaro Takagi, Karibu Fukuzawa, Naishen Liang, Masazumi Kayama, Mutsumi Nomura, Hajime Hojyo, Sadao Sugata, Hideaki Shibata, Tatsuya Fukazawa, Yoshiyuki Takahashi, Tatsuro Nakaji, Hiroyuki Oguma, Masayoshi Mano, Yukio Akibayashi, Takeshi Murayama, Takayoshi Koike, Kaichiro Sasa, Yasumi Fujinuma
    GLOBAL CHANGE BIOLOGY 15 (5) 1275 - 1288 1354-1013 2009/05 [Refereed][Not invited]
    To evaluate the effects on CO2 exchange of clearcutting a mixed forest and replacing it with a plantation, 4.5 years of continuous eddy covariance measurements of CO2 fluxes and soil respiration measurements were conducted in a conifer-broadleaf mixed forest in Hokkaido, Japan. The mixed forest was a weak carbon sink (net ecosystem exchange, -44 g C m(-2) yr(-1)), and it became a large carbon source (569 g C m(-2) yr(-1)) after clearcutting. However, the large emission in the harvest year rapidly decreased in the following 2 years (495 and 153 g C m(-2) yr(-1), respectively) as the gross primary production (GPP) increased, while the total ecosystem respiration (RE) remained relatively stable. The rapid increase in GPP was attributed to an increase in biomass and photosynthetic activity of Sasa dwarf bamboo, an understory species. Soil respiration increased in the 3 years following clearcutting, in the first year mainly owing to the change in the gap ratio of the forest, and in the following years because of increased root respiration by the bamboo. The ratio of soil respiration to RE increased from 44% in the forest to nearly 100% after clearcutting, and aboveground parts of the vegetation contributed little to the RE although the respiration chamber measurements showed heterogeneous soil condition after clearcutting.
  • Effect of nocturnal advection in a small valley on the vegetation-atmosphere CO2 flux
    OKADA Keiji, KATSURA Akihito, TAKAGI Kentaro, URANO Shin-ichi
    Journal of Agricultural Meteorology, Hokkaido 61 11 - 18 2009 [Refereed][Not invited]
  • Hiroyuki Tsuji, Takeshi Nakatsuka, Koji Yamazaki, Kentaro Takagi
    Journal of Geophysical Research Atmospheres 113 (18) 0148-0227 2008/09/27 [Refereed][Not invited]
    The summer relative humidity (RH) changes in Hokkaido, northern Japan, since 1776 were reconstructed using the oxygen isotope ratios of the tree ring cellulose of two living oak trees. We investigated the direct relationships between the decadal-centennial variations in the summer RH in northern Japan and the climate indices of atmospheric circulation to understand the factors affecting the changes in the hydrological climate in northern Japan. The variations in the summer RH are negatively correlated with those in the annual PDO indices since 1781. This is probably because the humid southerly wind from the western Pacific Ocean blows toward northern Japan with the intensified Pacific high when the PDO index is lower. Further, the fluctuations in the summer RH are positively correlated with those in the summer AO index during 1781-1930, but they are negatively correlated with those in the summer AO during 1940-1997. During the 1930s, the AO index changed from the negative to positive on the average. The drastic shift in its correlation is explained by the difference between atmospheric circulations in the low-AO period (1899-1930) and the high-AO period (1970-2000). The summer RH in northern Japan was regulated by the summer AO during 1781-1930 (the cold period) and the annual PDO during 1940-1997 (the warm period). As a consequence of global warming, the midlatitude forcing such as PDO might become stronger than the high-latitude forcing such as AO on the hydrological climate in northern Japan. Copyright 2008 by the American Geophysical Union.
  • Hiroyuki Tsuji, Takeshi Nakatsuka, Koji Yamazaki, Kentaro Takagi
    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES 113 (D18) 2169-897X 2008/09 [Refereed][Not invited]
    The summer relative humidity (RH) changes in Hokkaido, northern Japan, since 1776 were reconstructed using the oxygen isotope ratios of the tree ring cellulose of two living oak trees. We investigated the direct relationships between the decadal-centennial variations in the summer RH in northern Japan and the climate indices of atmospheric circulation to understand the factors affecting the changes in the hydrological climate in northern Japan. The variations in the summer RH are negatively correlated with those in the annual PDO indices since 1781. This is probably because the humid southerly wind from the western Pacific Ocean blows toward northern Japan with the intensified Pacific high when the PDO index is lower. Further, the fluctuations in the summer RH are positively correlated with those in the summer AO index during 1781-1930, but they are negatively correlated with those in the summer AO during 1940-1997. During the 1930s, the AO index changed from the negative to positive on the average. The drastic shift in its correlation is explained by the difference between atmospheric circulations in the low-AO period (1899-1930) and the high-AO period (1970-2000). The summer RH in northern Japan was regulated by the summer AO during 1781-1930 (the cold period) and the annual PDO during 1940-1997 (the warm period). As a consequence of global warming, the midlatitude forcing such as PDO might become stronger than the high-latitude forcing such as AO on the hydrological climate in northern Japan.
  • Norikazu Eguchi, Kazuki Karatsu, Tatsushiro Ueda, Ryo Funada, Kentaro Takagi, Tsutom Hiura, Kaichiro Sasa, Takayoshi Koike
    TREES-STRUCTURE AND FUNCTION 22 (4) 437 - 447 0931-1890 2008/08 [Refereed][Not invited]
    Though birch and alder are the common pioneer tree species which dominate in northeast Asia, little is known about the effects of the predicted increase in atmospheric CO2 concentrations ([CO2]) upon their photosynthesis in field conditions. To investigate this, we grew 2-year-old saplings of three Betulaceae species (Betula platyphylla var. japonica Hara, Betula maximowicziana Regel, and Alnus hirsuta Turcz) for 2 years in a free air CO2 enrichment system in northern Japan. Since the effect of high [CO2] is known to depend on soil conditions, we evaluated the responses in two soils which are widely distributed in northern Japan: infertile and immature volcanic ash (VA) soil, and fertile brown forest (BF) soil. For B. platyphylla, photosynthetic down-regulation occurred in both soils, but for B. maximowicziana, down-regulation occurred only in VA soil. The explanation is reduced nitrogen and Rubisco content in the leaf. For A. hirsuta, down-regulation occurred only in BF soil because of the accumulation of starch in foliage, which restricts CO2 diffusion inside the chloroplast. The higher photosynthetic rate of A. hirsuta in infertile VA soil could be due to the sink for photosynthates in the N-2-fixing symbiont. These three species are all able to down-regulate at high [CO2]. However, it is possible that A. hirsuta would dominate in VA soil and B. maximowicziana in BF soil in the early stages of forest succession in a CO2-enhanced world.
  • Ryuichi Hirata, Nobuko Saigusa, Susumu Yamamoto, Yoshikazu Ohtani, Reiko Ide, Jun Asanuma, Minoru Gamo, Takashi Hirano, Hiroaki Kondo, Yoshiko Kosugi, Sheng-Gong Li, Yuichiro Nakai, Kentaro Takagi, Makoto Tani, Huimin Wang
    AGRICULTURAL AND FOREST METEOROLOGY 148 (5) 761 - 775 0168-1923 2008/05 [Refereed][Not invited]
    The objective of this paper is to clarify what kind of environmental factors that regulate net ecosystem production (NEP), gross primary production (GPP), and ecosystem respiration (RE) in forest ecosystems across East Asia. Study sites were widely distributed and included diverse ecosystems, such as evergreen and deciduous, coniferous and broadleaf, planted and natural forests, from subarctic to tropical zones. We measured NEP using the eddy covariance technique at 13 forest sites in East Asia. Annual values of GPP and RE are simply regulated by annual mean air temperature across East Asia. There is a clear linear relationship between annual GPP and annual mean air temperature because the air temperature influences both growing period length and the seasonal variation of the maximum photosynthetic capacity, which, together, regulate the annual GPP. On the other hand, there is a strong exponential relationship between annual RE and annual mean air temperature on an East Asia scale, which is quite similar to the relation obtained on a canopy scale. The dependency of annual RE on air temperature on the East Asia scale was similar to that of monthly RE on air temperature on an individual site scale excepting for temperate larch and mixed forests in northern Japan. The reason why the relation is simple is that severe stress, which affects GPP or RE, is small in East Asia. The present study suggests that RE is sensitive to non-climate environmental factors when compared to GPP, thus the annual RE-air temperature relationship is more scattered than the annual GPP-air temperature relationship. The NEP is small at high latitude, relatively large at mid-latitude, and scattered at low latitude. As a whole, the NEP is more influenced by RE than GPP in East Asia. Compared to North America and Europe, the increase in the ratio of GPP to air temperature is slightly higher in East Asia. One of the possible reasons for this is that GPP in East Asia is not exposed to severe environmental stresses, such as summer drought. (C) 2007 Elsevier B.V. All rights reserved.
  • Nobuko Saigusa, Susumu Yamamoto, Ryuichi Hirata, Yoshikazu Ohtani, Reiko Ide, Jun Asanuma, Minoru Gamo, Takashi Hirano, Hiroaki Kondo, Yoshiko Kosugi, Sheng-Gong Li, Yuichiro Nakai, Kentaro Takagi, Makoto Tani, Huimin Wang
    AGRICULTURAL AND FOREST METEOROLOGY 148 (5) 700 - 713 0168-1923 2008/05 [Refereed][Not invited]
    Measurements of net ecosystem production (NEP) over forest stands were conducted from 11 flux towers in sub-arctic, temperate, and tropical regions in East Asia between 2000 and 2005. The sites extend over a wide latitude, ranging from 3 to 64 degrees N, and include sub-arctic and temperate needle-leaf deciduous forests (larch) (central Siberia, Mongolia, China, and northern Japan), temperate mixed, broadleaf deciduous, needle-leaf evergreen forests (northern and central japan), and seasonal and tropical rain forests (Thailand and Malaysia).The sub-arctic larch forests had short growing periods of 3-4 months. The temperate deciduous forests showed the greatest positive NEP after leaf expansion in early summer. Among the 11 sites, the maximum gross primary production (GPP) was observed in a temperate larch forest during the early stages of the growing period due to the high productivity of the larch species. The temperate evergreen sites displayed positive NEP earlier in the spring than the deciduous sites and had long growing periods (>10 months). The tropical seasonal forests showed negative NEP during the dry period from February to April, and turned positive after the rainy season started. The tropical rain forest showed a small flux (<30 g C m(-2) month(-1)) throughout the year without a clear seasonal change.In 2002 and 2003, several significant weather anomalies were observed, such as increased temperature in the temperate sites and less precipitation than average in the tropical sites in the beginning of 2002, and decreased solar radiation in the temperate sites in the 2003 summer. The seasonal patterns of NEP were sensitive to the anomalies, and the variations were caused by: (1) high spring air temperature, which induced an early start of the growing period in the temperate forests, (2) summer solar radiation, which controlled the summer GPP in the temperate forests with a slight variation among sites due to different responses of GPP to the temperature and water vapor pressure deficit (VPD) conditions, and (3) a long dry season, which significantly reduced GPP in a tropical seasonal forest.The dataset, which was obtained from a wide variety of forest ecosystems in East Asia over several years, is essential to validate ecosystem models and to generate technological developments of satellite remote sensing in the distribution of the terrestrial carbon budget in Asia. (C) 2007 Elsevier B.V. All rights reserved.
  • Tatsuro Nakaji, Reiko Ide, Kentaro Takagi, Yoshiko Kosugi, Shinjiro Ohkubo, Kenlo Nishida Nasahara, Nobuko Saigusa, Hiroyuki Oguma
    AGRICULTURAL AND FOREST METEOROLOGY 148 (5) 776 - 787 0168-1923 2008/05 [Refereed][Not invited]
    To clarify the utility of spectral vegetation indices (VIs) for estimating light conversion efficiency (epsilon) in Japanese coniferous forests, we investigated the relationships between six VIs (NDVI, EVI, SAVI, PRI, CI, and CCI) and epsilon in two mature monospecific forests of deciduous conifer (Japanese larch) and evergreen conifer (Japanese cypress) and one young mixed stand of deciduous conifer with evergreen undergrowth (hybrid larch and dwarf bamboo). In each forest canopy, we measured seasonal variations in CO2 flux, radiation environment, and visible-near-infrared spectral reflectance during 1 or 2 growing seasons. We calculated c as gross primary production (GPP) divided by the difference between incoming and reflected photosynthetically active radiation (PAR). VIs and epsilon under clear skies were averaged between 11:00 and 13:00 JST and their relationships were analyzed.In the larch forest, all calculated VIs were positively correlated with epsilon, and the highest correlation was that with CCI. Because of effects of extreme reduction in PRI in autumn with needle yellowing, the correlation of epsilon and PRI was relatively small in this forest. In the cypress forest, on the other hand, no significant correlation was found except with PRI and CCI. The highest correlation in this forest was that with PRI, suggesting that the leaf biomass-related VIs based on near-infrared reflectance are not sufficient for estimating epsilon of evergreen forest. In the mixed forest, with relatively sparse vegetation cover, all Vis were significantly correlated with epsilon, but the best correlation was that with SAVI, possibly owing to the reduction in the effect of the reflectance from background soil. Correlation analysis of the pooled data from all forests showed the highest correlation between epsilon and PRI. These results indicate that PRI is an effective VI in the remote estimation of epsilon in both deciduous and evergreen forests, although there are some sensitivity differences between vegetation types. (C) 2007 Elsevier B.V. All rights reserved.
  • Norikazu Eguchi, Noriko Morii, Tatsushiro Ueda, Ryo Funada, Kentaro Takagi, Tsutom Hiura, Kaichiro Sasa, Takayoshi Koike
    TREE PHYSIOLOGY 28 (2) 287 - 295 0829-318X 2008/02 [Refereed][Not invited]
    Water relations in woody species are intimately related to xylem hydraulic properties. High CO2 concentrations ([CO2]) generally decrease transpiration and stomatal conductance (g(s)), but there is little information about the effect of atmospheric [CO2] on xylem hydraulic properties. To determine the relationship between water flow and hydraulic structure at high [CO2], we investigated responses of sun and shade leaves of 4-year-old saplings of diffuse-porous Betula max-imowicziana Regel and ring-porous Quercus mongolica Fisch. ex Ledeb. ssp. crispula (Blume) Menitsky grown on fertile brown forest soil or infertile volcanic ash soil and exposed to 500 mu mol CO2 mol(-1) for 3 years. Regardless of species and soil type, elevated [CO2] consistently decreased water flow (i.e., g(s) and leaf-specific hydraulic conductivity) and total vessel area of the petiole in sun leaves; however, it had no effect on these parameters in shade leaves, perhaps because g, of shade leaves was already low. Changes in water flow at elevated [CO2] were associated with changes in petiole hydraulic properties.
  • Karibu Fukuzawa, Hideaki Shibata, Kentaro Takagi, Fuyuki Satoh, Takayoshi Koike, Kaichiro Sasa
    ECOLOGICAL RESEARCH 22 (3) 485 - 495 0912-3814 2007/05 [Refereed][Not invited]
    We measured the vertical distribution and seasonal patterns of fine-root production and mortality using minirhizotrons in a cool-temperate forest in northern Japan mainly dominated by Mongolian oak (Quercus crispula) and covered with a dense understory of dwarf bamboo (Sasa senanensis). We also investigated the vertical distribution of the fine-root biomass using soil coring. We also measured environmental factors such as air and soil temperature, soil moisture and leaf area indices (LAI) of trees and the understory Sasa canopy for comparison with the fine-root dynamics. Fine-root biomass to a depth of 60 cm in September 2003 totaled 774 g m(-2), of which 71% was accounted for by Sasa and 60% was concentrated in the surface soil layer (0-15 cm), indicating that understory Sasa was an important component of the fine-root biomass in this ecosystem. Fine-root production increased in late summer (August) when soil temperatures were high, suggesting that temperature partially controls the seasonality of fine-root production. In addition, monthly fine-root production was significantly related to Sasa LAI (P < 0.001), suggesting that fine-root production was also affected by the specific phenology of Sasa. Fine-root mortality was relatively constant throughout the year. Fine-root production, mortality, and turnover rates were highest in the surface soil (0-15 cm) and decreased with increasing soil depth. Turnover rates of production and mortality in the surface soil were 1.7 year(-1) and 1.1 year(-1), respectively.
  • Kentaro Takagi, Yoshinobu Harazono, Shin-ichi Noguchi, Akira Miyata, Masayoshi Mano, Masashi Komine
    AQUATIC BOTANY 85 (2) 129 - 136 0304-3770 2006/08 [Refereed][Not invited]
    To reveal the mechanism of transpiration by hydrophytes in the field, it is necessary to evaluate the transpiration rate without the effect of the evaporation from the water surface. In order to test the suitability for evaluating the transpiration rate of lotus (Nelumbo nucifera Gaertn.) leaves in the field, stem heat-balance method was applied and the obtained sap-flow rate was compared with the transpiration rate measured by weighing and with the overall canopy evapotranspiration rate by means of the eddy covariance technique. The transpiration rate estimated with the sap-flow measurements showed good agreement with that obtained from the weighing method. Lotus has many air canals in its petiole to carry oxygen-rich air to the rhizome and methane- and carbon dioxide-rich air back to the atmosphere, but there was little effect of the mass flow of air through these canals on the sap-flow rates. In the field observations, the canopy evapotranspiration rate (0.28 mm h(-1) at maximum) was nearly equal to the sum of the transpiration rate from all sunlit leaves (0.30 mm h(-1)), and the contribution of the transpiration from shaded leaves and evaporation from the water surface was considered to be minor in the seasons when the leaves were fully developed. Evaluation of bulk leaf conductance revealed that the conductance in the leaf boundary layer of lotus could be low (ca. 0.23 mol m(-2) s(-1)) because of its large leaf area. The low conductance in the leaf boundary layer would increase leaf temperature, which, in turn, would generate air circulation within the plant's ventilation system. Because there was a linear relationship between transpiration rate and the leaf-to-air vapor-pressure deficit, with no apparent maximum, high vapor-pressure deficits (3.4 kPa at maximum) did not appear to cause significant stomatal closure in lotus plants. The stomata of lotus leaves play a role as air inlets to carry oxygen-rich air to the rhizome, so their low sensitivity would help to increase air intake. (c) 2006 Elsevier B.V. All rights reserved.
  • Hiroyuki Tsuji, Takeshi Nakatsuka, Kentaro Takagi
    CHEMICAL GEOLOGY 231 (1-2) 67 - 76 0009-2541 2006/07 [Refereed][Not invited]
    Relationships between climatic factors and delta O-18 values of tree rings in two species with different root systems were investigated in the northern area in Hokkaido Island, northern Japan. This region has a heavy snow cover in winter and has a humid climate throughout the year. In the case of spruce (Picea jezoensis), which has shallow roots, the delta O-18 values are negatively correlated with precipitation in July and August, probably due to higher relative humidity in summer and lower delta O-18 of summer precipitation in a year of higher summer precipitation, which is governed by the precipitation amount effect. Thus, the delta O-18 value of tree-ring cellulose in spruce must be valuable as a proxy of summer precipitation in this area. On the other hand, the delta O-18 value in oak (Quercus crispula), which has deeper roots than spruce, is not very sensitive to summer precipitation, but is negatively correlated mainly with relative humidity in July and August; this can be attributed to the smaller O-18 enrichment in leaf water in the summer of higher relative humidity. Our results indicate that delta O-18 values of tree rings in two species with different root systems from the same forest have the potential to reconstruct the two different climate factors. (c) 2006 Elsevier B.V. All rights reserved.
  • K Fukuzawa, H Shibata, K Takagi, M Nomura, N Kurima, T Fukazawa, F Satoh, K Sasa
    FOREST ECOLOGY AND MANAGEMENT 225 (1-3) 257 - 261 0378-1127 2006/04 [Refereed][Not invited]
    cutting of understory vegetation, dwarf bamboo (Sasa senanensis), were investigated to understand the effect of these disturbances on biogeochemical processes on forested watershed in northern Japan. Tree-cutting did not cause a significant increase of nitrate (NO3-) concentration in stream water during the growing season after the cutting. Subsequent Sasa-cutting caused significant increase of stream NO3- concentration to ca. 15 mu mol L-1. There was no significant change of stream pH following both cuttings. NO3- concentration in soil solution increased after both cutting, but the change of concentration was higher (> 100 mu mol L-1) after the Sasa-cutting than after the tree-cutting. In a riparian conserved area, on the other hand, NO3- in soil solution remained low after tree-cutting, suggesting the riparian area acted as a NO3- sink after the tree-cutting. There was no significant change in total biomass of fine roots after the tree-cutting because of an increase in Sasa root biomass despite a decrease in tree roots. The subsequent Sasa-cutting caused a 50% decrease of fine root biomass compared to that in the un-cut Sasa site. These results suggested that nitrogen uptake by Sasa was very important in preventing nitrogen leaching after tree-cutting. and decline of this nitrogen uptake after Sasa-cutting lead to marked NO3- leaching to the stream. (c) 2006 Elsevier B.V. All rights reserved.
  • CO2 emissions of the non-tree vegetation cover in larch (Larix gmelinii (Rupr.)Rupr.) stands in the central Evenkia region of Siberia, Russia
    Masyagina, O.V, Prokushkin, S.G, Mori, S, Takagi, K, Nomura, M, Abaimov, A
    Eurasian Journal of Forest Research 9 17 - 28 2006 [Refereed][Not invited]
  • Hideaki Shibata, Tsutom Hiura, Yumiko Tanaka, Yumiko Tanaka, Kentaro Takagi, Takayoshi Koike
    Forest Ecosystems and Environments: Scaling Up from Shoot Module to Watershed 89 - 95 2005/12/01 [Not refereed][Not invited]
    Quantification of annual carbon sequestration is very important in order to assess the function of forest ecosystems in combatting global climate change and the ecosystem responses to those changes. Annual cycling and budget of carbon in a forested basin was investigated to quantify the carbon sequestration of a cool-temperate deciduous forest ecosystem in the Horonai stream basin, Tomakomai Experimental Forest, northern Japan. Net ecosystem exchange, soil respiration, biomass increment, litterfall, soil-solution chemistry, and stream export were observed in the basin from 1999-2001 as a part of IGBP-TEMA project. We found that 258 g C m-2 year-1 was sequestered annually as net ecosystem exchange (NEE) in the forested basin. Discharge of carbon to the stream was 4 g C m-2 year-1 (about 2% of NEE) and consisted mainly of dissolved inorganic carbon (DIC). About 43% of net ecosystem productivity (NEP) was retained in the vegetation, while about 57% of NEP was sequestered in soil, suggesting that the movement of sequestered carbon from aboveground to belowground vegetation was an important process for net carbon accumulation in soil. The derived organic carbon from aboveground vegetation that moved to the soil mainly accumulated in the solid phase of the soil, with the result that the export of dissolved organic carbon to the stream was smaller than that of dissolved inorganic carbon. Our results indicated that the aboveground and belowground interaction of carbon fluxes was an important process for determining the rate and retention time of the carbon sequestration in a cool-temperate deciduous forest ecosystem in the southwestern part of Hokkaido, northern Japan. © The Ecological Society of Japan.
  • H Shibata, T Hiura, Y Tanaka, K Takagi, T Koike
    ECOLOGICAL RESEARCH 20 (3) 325 - 331 0912-3814 2005/05 [Refereed][Not invited]
    Quantification of annual carbon sequestration is very important in order to assess the function of forest ecosystems in combatting global climate change and the ecosystem responses to those changes. Annual cycling and budget of carbon in a forested basin was investigated to quantify the carbon sequestration of a cool-temperate deciduous forest ecosystem in the Horonai stream basin, Tomakomai Experimental Forest, northern Japan. Net ecosystem exchange, soil respiration, biomass increment, litterfall, soil-solution chemistry, and stream export were observed in the basin from 1999-2001 as a part of IGBP-TEMA project. We found that 258 g C m(-2) year(-1) was sequestered annually as net ecosystem exchange (NEE) in the forested basin. Discharge of carbon to the stream was 4 g C m(-2) year(-1) (about 2% of NEE) and consisted mainly of dissolved inorganic carbon (DIC). About 43% of net ecosystem productivity (NEP) was retained in the vegetation, while about 57% of NEP was sequestered in soil, suggesting that the movement of sequestered carbon from above-ground to belowground vegetation was an important process for net carbon accumulation in soil. The derived organic carbon from aboveground vegetation that moved to the soil mainly accumulated in the solid phase of the soil, with the result that the export of dissolved organic carbon to the stream was smaller than that of dissolved inorganic carbon. Our results indicated that the aboveground and belowground interaction of carbon fluxes was an important process for determining the rate and retention time of the carbon sequestration in a cool-temperate deciduous forest ecosystem in the southwestern part of Hokkaido, northern Japan.
  • K Takagi, M Nomura, D Ashiya, H Takahashi, K Sasa, Y Fujinuma, H Shibata, Y Akibayashi, T Koike
    GLOBAL BIOGEOCHEMICAL CYCLES 19 (2) GB2012  0886-6236 2005/04 [Refereed][Not invited]
    CO2 efflux in the period of snow cover can be a large carbon source in the yearly carbon budget of snowy ecosystems. However, the behavior of CO2 in snowpacks and the mechanisms of the snow surface efflux are still unclear. We performed continuous (half-hourly) midwinter measurements of CO2 concentrations in a conifer-broadleaf mixed forest snowpack, and found that concentrations in the snowpack fluctuated significantly as wind speeds varied. The snow surface efflux was evaluated as the sum of the CO2 storage change in the snowpack and the CO2 input from the soil to the snowpack, taking into account the mixing due to airflow. The median value over 52 days (49 mmol m(-2) d(-1)) was almost the same as the daily net ecosystem exchange rate in this forest (50 mmol m(-2) d(-1)) estimated by the eddy covariance technique and the storage-change flux in the air column. These values are clearly larger than the value we estimated using Fick's law of diffusion. These results show that airflow can be a dominant cause of mixing within snowpacks in midwinter. In addition, in the soil pores under the snowpack, the CO2 concentration was primarily related to air temperature, implying that soil respiration responds directly to air temperature, not to soil temperature, even beneath a 1-m-thick snowpack. We infer that the air temperature affected the root activity of trees through their trunks and that the variation in root respiration strongly affected the CO2 concentration fluctuation in soil under the snowpack.
  • WJ Wang, YG Zu, HM Wang, T Hirano, K Takagi, K Sasa, T Koike
    JOURNAL OF FOREST RESEARCH 10 (1) 57 - 60 1341-6979 2005/02 [Refereed][Not invited]
    Little information is available on the effect of root cutting by the collar pre-insertion technique on soil respiration. In this study, we found that soil respiration rates decreased with increasing depth of collar insertion in both the "with live roots intact" and "with live roots severed" treatments, but the rate of decrease was substantially higher in the former. The cutting of roots, especially fine roots, may be responsible for this result.
  • Deforestation effects on the micrometeorology in a cool-temperate forest in northern Japan
    Takagi, K, Nomura, M, Fukuzawa, K, Kayama, M, Shibata, H, Sasa, K, Koike, T, Akibayashi, Y, Fujinuma, Y, Inukai, K, Maebayashi, M
    Journal of Agricultural Meteorology 60 1025 - 1028 2005 [Refereed][Not invited]
  • N. Eguchi, R. Funada, T. Ueda, K. Takagi, T. Hiura, K. Sasa, T. Koike
    PHYTON-ANNALES REI BOTANICAE 45 (4) 133 - 138 0079-2047 2005 [Refereed][Not invited]
    To better predict the soil moisture environment of cool-temperate forests, we studied the soil moisture for stands grown under elevated Co-2 concentration ([Co-2]) using Free Air Co-2 Enrichment (FACE) systems (50 Pa [CO2](e)) with controls at ambient levels (37 Pa [CO2](a))), over two years. Two distinct soil conditions, brown forest soil and volcanic ash soil, were prepared in each FACE. Two-year-old seedlings of six species were planted in May 2003. The soil moisture increased under [CO2](e) in both soil conditions. Since changes of soil moisture depend on evapotranspiration from a stand, we examined the fluctuation of soil moisture in relation to the transpiration (Tr) from leaves and evaporation (Ev) from the soil surface in the FACE. The Tr per leaf area decreased under [CO2](e) for both soil conditions, although the total Tr per seedling increased because the total leaf area per seedling increased under [CO2](e). Ev decreased under [CO2](e), because the soil surface temperature fell in both soils as a result of the increase of leaf area index (LAI), which blocked incident sunlight at the soil surface. These results show that the increase of soil moisture under [CO2](e) over two years is due probably to the change in Ev. Our results also indicate that the predicted rise in atmospheric [CO2] will lead to modification of the forest ecosystem accompanied by changing soil moisture conditions.
  • Process of larch plantation in northern Japan and development of hybrid larch (F1) for overcoming biological stress
    Koike, T, Kuromaru, M, Qu, L.Y, Choi, D.S, Takagi, K, Masyagina, O.V, Wang, W.J, Sasa, K
    2th International congress of Forest bioactive resources 63 - 65 2004 [Not refereed][Not invited]
  • CO2 control in a FACE system for tree saplings
    TAKAGI Kentaro, EGUCHI Norikazu, UEDA Tatsushiro, SASA Kaichiro, KOIKE Takayoshi
    Journal of Agricultural Meteorology, Hokkaido 56 9 - 16 2004 [Refereed][Not invited]
  • WJ Wang, FJ Yang, YG Zu, HM Wang, K Takagi, K Sasa, T Koike
    ACTA BOTANICA SINICA 45 (12) 1387 - 1397 0577-7496 2003/12 [Refereed][Not invited]
    Stem respiration is an important part of the activity of a tree and is an important source of CO2 evolution from a forest ecosystem. Presently, no standard methods are available for the accurate estimation of total stem CO2 efflux from a forest. In the current study, a 33-year-old (by the year 2001) larch (Larix gmelini Rupr.) plantation was measured throughout 2001-2002 to analyze its monthly and seasonal patterns of stem respiration. Stem respiration rate was also measured at different heights, at different daily intervals and any variation in the larch plantation was recorded. The relationship between stem temperature, growth status and respiration rate was analyzed. Higher respiration rates were recorded in upper reaches of the larch tree throughout the season and these were affected partially by temperature difference. Midday depression was found in the diurnal changes in stem respiration. In the morning, but not in the afternoon, stem respiration was positively correlated with stem temperature. The reason for this variation may be attributed to water deficit, which was stronger in the afternoon. In the larch plantation, a maximum 7-fold variation in stem respiration was found. The growth status (such as mean growth rate of stem and canopy projection area) instead of stem temperature difference was positively correlated with this large variation. An S-model (sigmoid curve) or Power model shows the greatest regression of the field data. In the courses of seasonal and annual changes of stem respiration, peak values were observed in July of both years, but substantial interannual differences in magnitude were observed. An exponential model can clearly show this regression of the temperature-respiration relationship. In our results, Q(10) values ranged from 2.22 in 2001 to 3.53 in 2002. Therefore, estimation of total stem CO2 efflux only by a constant Q(10) value may give biased results. More parameters of growth status and water status should be considered for more accurate estimation.
  • K Takagi, A Miyata, Y Harazono, N Ota, M Komine, M Yoshimoto
    AGRICULTURAL AND FOREST METEOROLOGY 115 (3-4) 173 - 181 0168-1923 2003/03 [Refereed][Not invited]
    We propose an alternative approach to determining zero-plane displacement by using friction velocities obtained by measuring wind profile and eddy correlation. In this approach, zero-plane displacement is determined so that the slope of the regression line between the friction velocities obtained from the wind profile and eddy correlation is close to 1. The approach was applied to a lotus paddy field in the back marsh of Lake Kasumigaura, Japan, and yielded acceptable results. The values determined for the normalized displacement height (0.13-0.91) and the normalized roughness length (0.023-0.092) of the lotus canopy were close to those of hard-canopy stands, such as forests and cornfields. These results are attributed to the unique structure of the lotus canopy (large, round leaves on the top of hard, thick shoots). In addition, the normalized displacement height of the lotus canopy increased linearly with the leaf area index (LAI). Because the number of comprehensive observation sites for flux measurements and micrometeorology has increased in recent years, this approach could be applicable to other study sites where there are problems in determining zero-plane displacement by the conventional method, which uses wind profile data alone. (C) 2002 Elsevier Science B.V. All rights reserved.
  • Makoto Ooba, Hidenori Takahashi, Kentaro Takagi
    Journal of Agricultural Meteorology 59 (4) 259 - 267 1881-0136 2003 [Refereed][Not invited]
    Photosynthesis of plants has been studied under a condition of alternating irradiance (irradiance changes between high and low values periodically). Based on results of previous studies, we hypothesized as follows: The mean photosynthetic rate (Ā) is minimum under conditions of alternating light with a period of about 102s when the period is in the order of 1 and 103s, Ā approaches a steady-state photosynthetic rate (A) at mean irradiance and mean A at both irradiances, respectively. We developed an unsteady-state leaf model to verify this hypothesis and estimated the relationship between the period and Ā. The hypothesis was verified by using the model. The relationship between the scale of fluctuating light and Ā which was shown in this study provides information to estimate dynamic response of a plant in a complicated light environment. © 2003, The Society of Agricultural Meteorology of Japan. All rights reserved.
  • T Tsuboya, K Takagi, H Takahashi, Y Kurashige, N Tase
    JOURNAL OF HYDROLOGY 252 (1-4) 100 - 115 0022-1694 2001/10 [Refereed][Not invited]
    We measured the diurnal change in groundwater level (GWL) and other hydrological factors in sphagnum peat in Sarobetsu Mire, Hokkaido. Japan. Field measurements confirmed that at nighttime, the GWL lowered just after a rainfall event and its rate of lowering slowed with time. until finally the GWL rose later in the night. At the study site, however, the groundwater inflow is minimal. The field experiment reproduced this tendency under the condition that the groundwater flow was completely interrupted. A new model was proposed to explain the GWL change during the night without groundwater flow, considering the peat-soil structure. Sphagnum peat has various scales of pores, including those found on the inside of plant cell walls. These pores were classified into two types based on their water infiltration capacity. One is the large pores that can easily be filled with water and also can be easily drained. The GWL is determined by the water in these large pores. The other types are the small pores that cannot be filled with water or drained of water so easily. Just after a rainfall event, the water potential in the large pores is larger than that in the small pores, and accordingly the discharge from the large pores to the small pores occurs. Since the GWL is determined by the large pores. the GWL decreases during the night. The GWL rate of decline slows, as the difference in the two pore potentials grows smaller. Further, when the water potential in the large pores in the night becomes lower than that in the small pores after intensive evapotranspiration, the water starts to move from the small pores to the large pores, and consequently the GWL increases later in the night. The diurnal change in the water loss from the large pores was compared with that caused by evapotranspiration. The comparison showed that all of the water loss from the large pores during daytime was evapotranspiration, whereas the water loss from the large pores during nighttime was mostly in the form of the storage change in the small pores. The storage change in the small pores in a day ranged from -0.19 to 0.21 cm day(-1), and these values were a large proportion of the day's total evapotranspiration. The characteristics of the subsurface water movement in sphagnum peat indicate that the sphagnum peat acts as a buffer zone to prevent drastic changes in the GWL. (C) 2001 Elsevier Science BN. All rights reserved.
  • Basic data for CO2 flux monitoring of a young larch plantation--Current status of a mature, mixed conifer-broadleaf forest stand --
    Koike, T, Hojyo, H, Naniwa, A, Ashiya, D, Sugata, S, Sugishita, Y, Kobayashi, M, Nomura, M, Akibayashi, Y, Nakajima, J, Takagi, K, Shibata, H, Satoh, F, Wang, W, Takada, M, Fujinuma, Y, Shi, F, Matsuura, Y, Sasa, K
    Eurasian Journal of Forest Research 2 65 - 79 2001 [Refereed][Not invited]
  • Vegetation Characteristics of a Larch-dominant Site for CO2 Flux: Monitoring Study at the Laoshan Experimental Station in Northeast China
    Shi, F, Xiangwei, C, Wang, W, Takagi, K, Akibayashi, Y, Sasa, K, Uemura, S
    Eurasian Journal of Forest Research 3 55 - 67 2001 [Refereed][Not invited]
  • Meteorological characteristics of northern Hokkaido University Forests during 1995-1999
    TAKAGI Kentaro, SASA Kaichiro, SATO Fuyuki, NOMURA Mutsumi, KOMIYA Keiji, TAKAHASHI Hiroyuki, Hojyo Hajime, KANEKO Kisyohi, ICHIKAWA Kazu, NAKAJIMA Junko, ASHIYA Daitaro, ISHIDA Sachinobu, OKUDA Atsushi, NANIWA Aiko, OKAMOTO Tomoko
    Research Bulletin of the Hokkaido University Forests 58 (1) 29 - 36 2001 [Refereed][Not invited]
  • K Takagi, T Tsuboya, H Takahashi, T Inoue
    WETLANDS 19 (1) 246 - 254 0277-5212 1999/03 [Refereed][Not invited]
    To assess the effect of the invasion of vascular plants on the heat and water balance in a Sphagnum bog, evapotranspiration was compared throughout a growing season in the Sphagnum bog and in the adjoining transition peatland where vascular plants completely cover the ground surface in the Sarobetsu mire, northern Japan. Cumulative evapotranspiration over 152 days was 372 mm in the transition peatland and 285 mm in the bog, with the differences between the sites becoming clear from mid-August. Therefore, we consider the invasion of the vascular plants into the Sphagnum bog to accelerate water consumption. However, levels of evapotranspiration in mid-summer did not differ greatly between the sites. In mid-summer, the ratio of latent heat flux to net radiation decreased in the transition peatland on days when humidity deficit was large, although, in the bog, the ratio showed a large value in those days. We attribute the decrease in the ratio to stomatal closure with the increase in humidity deficit. We also conclude that the invading vascular plants developed a negative feedback mechanism of stomatal response to the humidity deficit of the ambient air in mid-summer.
  • Yoshinobu Harazono, Asashi Komine, Entaro Takagi, Hirokazu Komuro
    Journal of Agricultural Meteorology 55 (2) 173 - 178 1881-0136 1999/01/01 [Refereed][Not invited]
    The “Ecosystem Database” has been developed to provide data on the issue of gas and energy exchange in various terrestrial ecosystems. These data are essential to verify modeling studies in global change issues but have not been available before. The data were obtained over grasslands, tundra, wetlands, shrub lands, dune, rice paddies and some agricultural fields. Numerical data were checked and quality controlled and then averaged for every 30min. In addition, the database includes site maps, photographs, and comments on data acquisition and quality. The Ecosystem Database is available through the World Wide Web. This system is designed to produce a requested graph, which allows users to select data that they want. The system will be open to the public beginning in October 1999. However the operation and control test will be provided for some researchers in advance. © 1999, The Society of Agricultural Meteorology of Japan. All rights reserved.
  • K Takagi, T Tsuboya, H Takahashi
    AGRICULTURAL AND FOREST METEOROLOGY 91 (3-4) 177 - 191 0168-1923 1998/06 [Refereed][Not invited]
    In order to evaluate the stomatal control on the canopy evapotranspiration, diurnal variations in stomatal conductance (g(s)) of individual plants and bulk surface conductance (G(s)) of the canopy were measured independently in the Sarobetsu mire of northern Japan. During July-August 1993 and 1994, g(s) was measured for four species (Sasa palmata, Moliniopsis japonica, Myrica gale L. var. tomentosa and Ilex crenata var. paludosa) growing in the mire. In July and August 1995, G(s) was determined using Penman-Monteith equation. In this equation, evapotranspiration rate was determined by the Bowen ratio/energy balance method. Diurnal hysteresis curves of g(s) in relation to leaf-to-air vapor pressure deficit (nu) followed different courses from day to day according to the magnitude of nu, and daily maximum g(s) was correlated negatively with daily maximum nu except for Ilex crenata var. paludosa. Similar clockwise hysteresis curves were observed between G(s) and Vapor pressure deficit at the mean evaporative surface (D-0), and daily maximum G(s) decreased with daily maximum D-0 in midsummer. In particular, on days when daily maximum D-0 increased up to 1.9 kPa, the large decrease in G(s) decreased the evapotranspiration rate, despite high irradiance levels. Thus, stomatal control by individual plant leaves strongly affects evapotranspiration from the canopy and prevents excessive water loss on days when vapor pressure deficit is high, even when soil water is plentiful. On the rising limb of the diurnal course of the transpiration rate (T-r), increases in T-r with change in nu, Delta T-r/Delta nu varied from day to day, in particular for M. gale L. var, tomentosa. Further, a negative relationship was found between Delta T-r/Delta nu and the rate of increase of nu for unit change in time. We believe that the change of the daily course of g(s) and T-r was caused by the response of stomata to the increased rate of change of nu. Thus, in order to predict the diurnal variation of g(s), the magnitude and tendency of nu for each day must be considered. (C) 1998 Elsevier Science B.V. All rights reserved.
  • Diurnal variation of soil water content in Sarobetsu mire
    TSUBOYA Taro, TAKAGI Kentaro, KURASHIGE Yoshimasa, TASE Norio
    Journal of Japanese Association of Hydrological Sciences 27 (3) 129 - 141 1997 [Refereed][Not invited]

Books etc

  • 湿地の科学と暮らし ― 北のウェットランド大全
    高木 健太郎 (Joint work大気・湿原生態系間の水とエネルギー)
    北海道大学出版会 2017
  • 北海道の気象と農業
    高木 健太郎 (Joint work森林土壌への温暖化の影響)
    北海道新聞社 2012
  • 北海道の森林
    高木健太郎 (Joint work森林のCO2固定)
    北海道新聞社 2011
  • 北の森づくりQ&A
    高木健太郎 (Joint work森は二酸化炭素をどのくらい吸収する?)
    社団法人北方林業会 2009
  • 森林の科学―森林生態系科学入門―
    高木 健太郎 (Joint work森林生態系の二酸化炭素吸収量を調べる,)
    朝倉書店 2005


  • 北方森林圏データベース
  • Forest Research Database


  • A large scale evaluation of effect of changing environment on forest stands: results from a Free Air CO2 or O3 enrichment system
    Koike T, Eguchi N, Watanabe T, Ichikawa K, Fujito E・Qu LY, Watanabe M, Watanabe Y, Agathokleou E, Kitao M, Takagi K, Hiura T, Nakaba S, Satomura T, Funada R, Satoh F  北方森林保全技術  37-  2020/02  [Not refereed][Not invited]
  • LIANG NAISHEN, Ando Mariko, Ishida Sachinobu, Takagi Masahiro, Takahashi Yoshiyuki, Teramoto Munemasa, Zhao Xin, Tomimatsu Hajime, Takagi Kentaro, Hirano Takashi, Kondo Toshiaki, Koarashi Jun  The Japanese Forest Society Congress  130-  (0)  701  -701  2019  [Not refereed][Not invited]

    [in Japanese]

  • 片山歩美, BRYANIN Semyon V, 高木健太郎, 小林真  日本生態学会大会講演要旨(Web)  65th-  ROMBUNNO.P2‐306 (WEB ONLY)  2018  [Not refereed][Not invited]
  • 丸毛絵梨香, 高木健太郎, 関宰, 小林真  日本生態学会大会講演要旨(Web)  64th-  ROMBUNNO.P1‐R‐464 (WEB ONLY)  2017  [Not refereed][Not invited]
  • 小林真, 片山歩美, 丸毛絵梨香, BRYANIN Semyon, 高木健太郎  日本生態学会大会講演要旨(Web)  64th-  ROMBUNNO.P2‐B‐047 (WEB ONLY)  2017  [Not refereed][Not invited]
  • 坂井励, 吉田俊也, 小塚力, 高木健太郎, 岸田治, 片山昇, 高橋廣行, 浪花愛子, 伊藤欣也, 実吉智香子, 五十嵐満, 和田克法, 大岩敏昭, 永井義隆, 古和田四郎, 小池義信, 椿本勝博, 大岩健一, 佐藤博和, 宮崎徹, 大岩真一, 岡翼  北方森林保全技術  (32)  1  -11  2015/03/23  [Not refereed][Not invited]
  • 高木健太郎, 米康充, 野村睦, 笹賀一郎, 藤沼康実, 村山岳史, 小熊宏之  日本農業気象学会全国大会講演要旨  2014-  159  2014  [Not refereed][Not invited]
  • 森林からのメタン発生:進行する高CO2環境の影響
    小池孝良, 高木健太郎, 佐藤冬樹  北方林業  66-  284  -287  2014  [Not refereed][Not invited]
  • MATSUDA Kazuhide, KHUMMONGKOl Pojanie, SASE Hiroyuki, MURAO Naoto, NOGUCHI Izumi, FUKAZAWA Tatsuya, HAYASHI Kentaro, TAKAHASHI Akira, TAKAGI Kentaro, YAMAGUCHI Takashi  Earozoru Kenkyu  29-  (1)  s160  -s167  2014  [Refereed][Not invited]
    Recent research on aerosol dry deposition in forests in East Asia, focusing particularly on field measurements, estimations of deposition rates, and developments of measurement technique, was reviewed to contribute assessments of the impacts of aerosols on vegetation. Some measurements of aerosol deposition by the gradient method indicated that the deposition velocities were in agreement with other experimental results in North America and Europe, and were higher than those calculated by theoretical models. Higher deposition velocities were associated with larger friction velocities and unstable conditions. The deposition velocities were possibly influenced by humidity, due to the growth in size of hygroscopic aerosols and the enhancement of surface collection efficiency. Some estimations of aerosol deposition rates indicated i) high ratios of sulfate to SO2 in deposition rates in remote areas of Japan, ii) high dry deposition of elemental carbon on a tropical forest, and iii) about 10~20% year to-year variations in aerosol deposition, with a higher percentage variation in tropical areas. Regarding aerosol deposition on forest leaves, there was larger deposition in higher parts than in lower parts, and approximately 70% of total aerosol deposition onto forests probably deposit on forest leaves during the leafy season. It is indicated that the relaxed eddy accumulation method could obtain more accurate data on the fluxes of aerosol components than data obtained with the gradient method.
  • HARA Yuko, ITO Hirotaka, MAO Qiao-zhi, WATANABE Makoto, TAKAGI Kentaro, SATO Fuyuki, KOIKE Takayoshi  Boreal forest research  61-  (61)  41  -42  2013/02/18  [Not refereed][Not invited]
  • 小池孝良, 渡辺 誠, 渡邊陽子, 江口則和, 高木健太郎, 佐藤冬樹, 船田 良  科学と生物  51-  559  -565  2013  [Not refereed][Not invited]
  • An automated-chamber network for evaluation of carbon budget of Asian terrestrial ecosystems
    Liang, N, Wang, Y, Zhang, Y, He, J, Li, S, Piao, S, Fang, J, Hirano, T, Takagi, K, Fletcher, C.D, Teramoto, M, Tan, Z.-H  AsiaFlux Newsletter  35-  3  -12  2013  [Not refereed][Not invited]
  • WATANABE Makoto, KITAOKA Satoshi, EGUCHI Norikazu, WATANABE Yoko, SATOMURA Takami, TAKAGI Kentaro, SATOH Fuyuki, KOIKE Takayoshi  大気環境学会年会講演要旨集  (53)  2012/08/29  [Not refereed][Not invited]
  • WATANABE Makoto, TAKAGI Kentaro, SATOH Fuyuki, KOIKE Takayoshi  大気環境学会年会講演要旨集  (53)  2012/08/29  [Not refereed][Not invited]
  • MATSUDA Kazuhide  大気環境学会年会講演要旨集  (53)  86  -87  2012/08/29  [Not refereed][Not invited]
  • HARA Yuko, ITO Hirotaka, MAO Quao-zhi, WATANABE Makoto, HOSHIKA Yasutomo, TAKAGI Kentaro, SAITO Hideyuki, SHIBUYA Masato, KOIKE Takayoshi  Boreal forest research  60-  (60)  39  -40  2012/02/18  [Not refereed][Not invited]
  • WATANABE Makoto, UEDA Tatsushiro, TAKAGI Kentaro, SASA Kaichiro, KOIKE Takayoshi  Boreal forest research  60-  (60)  41  -42  2012/02/18  [Not refereed][Not invited]
  • Tsunogai Urumu, Komatsu Daisuke D, Suzuki Atsushi, Nakagawa Fumiko, Fukuzawa Karibu, Shibata Hideaki, Takagi Kentaro, Nomura Mutsumi  Abstracts of Annual Meeting of the Geochemical Society of Japan  59-  (0)  2012  [Not refereed][Not invited]
  • 高木健太郎, 平田竜一, 平野高司, 植山雅仁, 小野圭介, 井手玲子, 小川安紀子, 三枝信子, 高橋善幸, 市井和仁, KWON H, HONG J, LEIMING Z, LI S.‐G, HAN S, WANG H.‐M, ZHANG Y.‐P, 浅沼順, 蒲生稔, 前田高尚, 村山昌平, 町村尚, 中井裕一郎, 太田岳史, 斎藤琢  日本農業気象学会全国大会講演要旨  2012-  33  2012  [Not refereed][Not invited]
  • 小塚 力, 高木 健太郎, 岸田 治  北方森林保全技術  0-  (29)  1  -13  2011/11  [Not refereed][Not invited]
  • ITO Hirotaka, WATANABE Makoto, MAO Qiao-zhi, NOVRIYANTI Eka, UEDA Tatsushiro, TAKAGI Kentaro, SASA Kaichiro, SAITO Hideyuki, SHIBUYA Masato, KOIKE Takayoshi  日本森林学会北海道支部論文集  59-  (59)  35  -38  2011/02/19  [Not refereed][Not invited]
  • WATANABE Makoto, MAO Qiaozhi, NOVRIYANTI Eka, ITO Hirotaka, UEDA Tatsushiro, TAKAGI Kentaro, SASA Kaichiro, KOIKE Takayoshi  日本森林学会北海道支部論文集  59-  (59)  39  -40  2011/02/19  [Not refereed][Not invited]
  • Nomura Mutumi, Takagi Kentaro, Hojo Hajime, Takahashi Hiroyuki, Sakai Rei, Ito Kinya, Miyoshi Chikako  JSSI & JSSE Joint Conference  2011-  (0)  184  -184  2011  [Not refereed][Not invited]
  • Hara Yuko, Ito Hirotaka, Nakaji Tatsuro, Watanabe Makoto, Takagi Kentaro, Sato Fuyuki, Koike Takayoshi  The Japanese Forest Society Congress  123-  (0)  Pb181  -Pb181  2011  [Not refereed][Not invited]
  • 北海道大学天塩研究林の取組み
    高木 健太郎  公益社団法人北海道森と緑の会会誌「山つくり」  平成22年度版-  17  -17  2011  [Not refereed][Invited]
  • SHIBATA Hideaki, TAKAGI Kentaro, YOSHIDA Toshiya, FUKUZAWA Karibu, SATO Fuyuki, SASA Kaichiro  Water science  317-  30  -42  2011  [Refereed][Not invited]
  • 宮川浩樹, 深澤達矢, 野口泉, 高橋正宏, 佐藤久, 福澤加里部, 柴田英昭, 野村睦, 高木健太郎, 三枝信子  環境化学討論会講演要旨集  19th-  130  -131  2010/06/20  [Not refereed][Not invited]
  • RYU Koharu, WATANABE Makoto, TAKAGI Kentaro, NOMURA Mutsumi, KOIKE Takayoshi  Transactions of the Meeting in Hokkaido Branch of the Japanese Forest Society  58-  (58)  17  -20  2010/02/19  [Not refereed][Not invited]
  • Report of the AsiaFlux Workshop 2009-Integrating Cross-scale Ecosystem Knowledge: Bridges and Barriers-
    TAKAGI Kentaro  AsiaFlux Newsletter  31-  2  -5  2010  [Not refereed][Not invited]
  • 蛇紋岩土壌におけるグイマツ雑種F1利用の可能性-窒素沈着量の増加を考慮した苗木植栽試験
    RYU Koharu, WATANABE Makoto, TAKAGI Kentaro, KOIKE Takayoshi  Forest tree breeding of Hokkaido  53-  25  -28  2010  [Refereed][Not invited]
  • 福澤 加里部, 柴田 英昭, 高木 健太郎, 佐藤 冬樹, 笹賀 一郎, 小池 孝良  根の研究 = Root research  18-  (2)  2009/06/26  [Not refereed][Not invited]
  • 長谷川祥樹, 深澤達矢, 野口泉, 高橋正宏, 佐藤久, 福澤加里部, 柴田英昭, 野村睦, 高木健太郎, 藤沼康実, 佐々木巴え  環境化学討論会講演要旨集  18th-  78  -79  2009/06/09  [Not refereed][Not invited]
  • 笠小春, 渡辺誠, 玉井裕, 小池孝良, 柴田英昭, 高木健太郎, 野村睦  日本森林学会大会学術講演集(CD−ROM)  120th-  ROMBUNNO.PA3-06  2009/03/25  [Not refereed][Not invited]
  • 渡辺誠, 北岡哲, 渡辺陽子, 小林真, 上田龍四郎, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本生態学会大会講演要旨集  56th-  280  2009/03/17  [Not refereed][Not invited]
  • Nomura Mutumi, Takagi Kentaro, Hojyo Hajime, Takahashi Hiroyuki, Kozuka Chikara, Sakai Rei, Ito Kinya, Miyoshi Cikako  JSSI & JSSE Joint Conference  2009-  (0)  29  -29  2009  [Not refereed][Not invited]
  • 中の峰山火事跡地植栽試験地の成績調査結果と蓄積推定
    高橋廣行, 高木健太郎, 北條元, 小塚力, 坂井励, 伊藤欣也, 實吉智香子, 野村睦  北方森林保全技術  27-  1  -5  2009  [Not refereed][Not invited]
  • 全木集材方式による未利用バイオマス収集コスト削減と林内物質動態への影響
    永岡彩, 秋林幸男, 野村睦, 高木健太郎, 上浦達哉, 北條元, 高橋廣行, 小塚力, 坂井励, 笹賀一郎  日本林学会北海道支部論文集  57-  199  -201  2009  [Not refereed][Not invited]
  • 大気中CO2濃度の増加が冷温帯落葉広葉樹の成長及び競争関係にもたらす影響
    江口則和, 高木健太郎, 日浦勉, 笹賀一郎, 上田龍四朗, 船田良, 小池孝良  日本林学会北海道支部論文集  57-  187  -189  2009  [Not refereed][Not invited]
  • 窒素付加が蛇紋岩土壌に植栽したグイマツ雑種F1の光合成と成長に与える影響
    笠小春, 渡辺誠, 高木健太郎, 柴田英昭, 野村睦, 小池孝良  日本林学会北海道支部論文集  57-  49  -51  2009  [Not refereed][Not invited]
  • 環境変化に対するカラマツ類の応答を探る~研究の動向と今後の方向性~
    笠小春, 野村睦, 高木健太郎, 小池孝良  北方林業  61-  32  -35  2009  [Not refereed][Not invited]
  • Long-term monitoring of carbon and water cycles in larch forest ecosystems in East Asia
    Saigusa, N, Takagi, K, Hirano, T  iLEAPS Newsletter  6-  44  -45  2009  [Not refereed][Not invited]
  • 航空機リモートセンシングを用いた森林バイオマス量の計測について
    TAKAGI Kentaro  Journal of Agricultural Meteorology, Hokkaido  61-  29  -36  2009  [Refereed][Not invited]
  • 小池 孝良, 江口 則和, 渡辺 誠, 渡邊 陽子, 北岡 哲, 里村 多香美, 高木 健太郎, 柴田 英昭, 日浦 勉, 笹 賀一郎, 船田 良  Technical report for boreal forest conservation of the Hokkaido University Forests  (26)  47  -52  2008/11  [Not refereed][Not invited]
    はじめに:モジュールFACEとは、モジュール(部材)単位でのCO2付加実験を野外で行ない(Free Air CO2 Enrichment; FACE,)開放系大気CO2増加)、大気中のCO2濃度が上昇する環境での樹木の成長応答とCO2固定・貯留能力を調べる施設のことである(小池ら 1995)。当初、予算規模から、シュートや枝単位でのCO2付加を想定していた。しかし、設計・施工に貢献された上田龍四郎氏(北海道ダルトン)の技術によって(山武ニュース 2002)、スイス・バーゼル大学と山岳FACEを基礎にした北大独自のFACEが完成した(江口ら 2004,Eguchi et al. 2005, 小池ら 2005)。本来は、森林全体を対象に研究できる実験施設の設置を予定したが(DukeFACE 2007)、予算の制約から小規模のFACEを設けることになった。しかし、このことによって進行し続ける大気CO2増加に伴う温暖化条件での落葉樹11種の成長応答を、土壌条件を加味して調査することができた(江口ら 2004, 小池ら 2005)。当初の文科省予算が終了し、いわば第二期に入ったので、これまでの予算の流れと研究の構成をまとめ、現在、運転中のシステムを紹介する。これによって、実験苗畑の施設の利活用の基礎資料としたい。
  • NOGUCHI Izumi, YAMAGUCHI Takashi, TAKAGI Kentaro, FUKAZAWA Tatsuya, HAYASHI Kentaro, SAEGUSA Nobuko  大気環境学会年会講演要旨集  (49)  2008/08/29  [Not refereed][Not invited]
  • 深澤達矢, 長谷川祥樹, 佐藤久, 高橋正宏, 柴田英昭, 野村睦, 高木健太郎, 藤沼康実  環境化学討論会講演要旨集  17th-  214  -215  2008/06/10  [Not refereed][Not invited]
  • Changes in petiole hydraulic structure and leaf water flow in birch and oak saplings in an enhanced CO2 environment
    Eguchi N, Mori N, Ueda T, Funada R, Takagi K, Hiura T, Sasa K, Koike T  Tree Physiology  28-  287  -295  2008  [Not refereed][Not invited]
  • Nomura Mutumi, Takagi Kentaro, Hojyo Hajime, Takahashi Hiroyuki, Kozuka Chikara, Sakai Rei, Ito Kinya, Sasa Kaichiro  JSSI & JSSE Joint Conference  2008-  (0)  82  -82  2008  [Not refereed][Not invited]
  • Fukuzawa Karibu, Satomura Takami, Shibata Hideaki, Takagi Kentaro, Satoh Fuyuki, Koike Takayoshi, Sasa Kaichiro  The Japanese Forest Society Congress  119-  (0)  107  -107  2008  [Not refereed][Not invited]
  • Sasa Kaichiro, Satoh Fuyuki, Shibata Hideaki, Takagi Kentaro, Takahata Mamoru, Sugishita Yoshiyuki, Fukui Tomizo, Mamiya Haruhiro, Sugata Sadao, Okuyama Satoru, Ishii Tadashi, Fujito Eishi, Ishida Nobuo, Okuda Atsushi, Ichikawa Kazu, Arikura Kiyomi, Koike Takayoshi, Suzuki Teppei, Qu Laiye, Fujinuma Yasumi  The Japanese Forest Society Congress  119-  (0)  160  -160  2008  [Not refereed][Not invited]
  • 「北海道の農業気象」について思うこと
    高木 健太郎  北海道の農業気象  60-  5  -5  2008  [Not refereed][Invited]
  • Inter-comparison of eddy flux calculation and QC/QA procedure of three flux networks (ChinaFLUX, JapanFlux and KoFlux) under AsiaFlux
    Takagi, K, Hirata, R, Wen, X, Kwon, H, Saigusa, N, Ono, K, Miyata, A  AsiaFlux Newsletter  26-  8  -11  2008  [Not refereed][Not invited]
  • 火入れ処理が北海道のササ地における土壌のリンと窒素に与える影響に関する研究
    小林真, 金容ソク, 松井克彦, 野村睦, 柴田英昭, 里村多香美, 上浦達哉, 北條元, 高橋廣行, 小塚力, 坂井励, 高木健太郎, 佐藤冬樹, 笹賀一郎, 小池孝良  日本林学会北海道支部論文集  56-  29  -31  2008  [Not refereed][Not invited]
  • 高CO2環境下で生育する冷温帯落葉広葉樹の水分通道と木部構造の変化
    江口則和, 里村多香美, 渡邊陽子, 高木健太郎, 日浦勉, 笹賀一郎, 北岡哲, 上田龍四朗, 船田良, 小池孝良  日本林学会北海道支部論文集  56-  25  -27  2008  [Not refereed][Not invited]
  • 中路達郎, 井手玲子, 高木健太郎, 小杉緑子, 大久保晋治郎, 西田顕郎, 三枝信子, 小熊宏之  CGER リポート  M019-2008-  97  -98  2008  [Not refereed][Not invited]
  • 井手玲子, 中路達郎, 小熊宏之, 高木健太郎, 三枝信子  CGER リポート  M019-2008-  77  -78  2008  [Not refereed][Not invited]
  • チャンバー法による土壌からの炭素放出観測の展開
    梁乃申, 藤沼康実, 向井人史, 高橋善幸, Seong-Dong Kim, 平野高司, 高木健太郎, 下山宏, 中根周歩, Yongwon Kim  CGER リポート  M019-2008-  33  -36  2008  [Not refereed][Not invited]
  • 伐採・植林などの森林施業が北海道北部森林小流域の炭素・水・窒素動態に与える影響
    高木健太郎, 福沢加里部, 梁乃申, 野村睦, 柴田英昭, 深澤達矢, 野口泉, 小熊宏之, 秋林幸男, 笹賀一郎, 小池孝良, 藤沼康実, 水野真人, 村山岳史  CGER リポート  M019-2008-  27  -32  2008  [Not refereed][Not invited]
  • 高木 健太郎, 小宮 圭示, 柴田 英昭  Technical report for boreal forest conservation of the Hokkaido University Forests  0-  (25)  40  -45  2007/11  [Not refereed][Not invited]
  • 深澤達矢, 長谷川祥樹, 高橋正宏, 太田幸雄, 福澤加里部, 高木健太郎, 野村睦, 柴田英昭, 野口泉, 藤沼康実  大気環境学会年会講演要旨集  48th-  292  2007/08/24  [Not refereed][Not invited]
  • 中島篤, 深澤達矢, 長谷川祥樹, 高橋正宏, 福澤加里部, 柴田英昭, 野村睦, 高木健太郎, 藤沼康実  環境化学討論会講演要旨集  16th-  222  -223  2007/06/19  [Not refereed][Not invited]
  • 深澤遠矢, 長谷川祥樹, 高橋正宏, 福澤加里部, 柴田英昭, 野村睦, 高木健太郎, 藤沼康実, 飛澤拓也  環境化学討論会講演要旨集  16th-  226-227  2007/06/19  [Not refereed][Not invited]
  • 崔東寿, 渡邊陽子, 秋林幸男, 高木健太郎, 笹賀一郎, 北岡哲, 江口則和, 小池孝良  日本森林学会大会学術講演集(CD-ROM)  118th-  P1F06  2007/04/01  [Not refereed][Not invited]
  • 江口則和, 唐津一樹, 飛弾剛, 森井紀子, 上里季悠, 松井克彦, 上田龍四郎, 高木健太郎, 船田良, 日浦勉, 笹賀一郎, 小池孝良  日本森林学会大会学術講演集(CD-ROM)  118th-  P1I11  2007/04/01  [Not refereed][Not invited]
  • 江口則和, 森井紀子, 上田龍四郎, 高木健太郎, 船田良, 日浦勉, 笹賀一郎, 小池孝良  日本生態学会大会講演要旨集  54th-  144  2007/03/19  [Not refereed][Not invited]
  • ISHII Yuuki, TAKEUCHI Yuichi, EGUCHI Norikazu, KARATSU Kazuki, UEDA Tatsushiro, TAKAGI Kentaro, HIURA Tsutom, SASA Kaichiro, KOIKE Takayoshi  Transactions of the Meeting in Hokkaido Branch of the Japanese Forest Society  55-  (55)  47  -49  2007/02/21  [Not refereed][Not invited]
  • EGUCHI Norikazu, MORII Noriko, UEDA Tatsushiro, FUNADA Ryo, TAKAGI Kentaro, HIURA Tsutom, SASA Kaichiro, KOIKE Takayoshi  Transactions of the Meeting in Hokkaido Branch of the Japanese Forest Society  55-  (55)  50  -52  2007/02/21  [Not refereed][Not invited]
  • MORII Noriko, EGUCHI Norikazu, IKEDA Takefumi, WATANABE Yoko, TAKAGI Kentaro, HIURA Tsutom, SASA Kaichiro, KOIKE Takayoshi  Transactions of the Meeting in Hokkaido Branch of the Japanese Forest Society  55-  (55)  53  -55  2007/02/21  [Not refereed][Not invited]
  • Sasa Kaichiro, Oikawa Masatoshi, Akibayashi Yukio, Nomura Mutsumi, Takagi Kentaro, Kamiura Tatsuya, Hojyo Hajime, Takahashi Hiroyuki, Kozuka Chikara, Sakai Rei  The Japanese Forest Society Congress  118-  (0)  216  -216  2007  [Not refereed][Not invited]
  • Fukuzawa Karibu, Shibata Hideaki, Takagi Kentaro, Satoh Fuyuki, Koike Takayoshi, Sasa Kaichiro  The Japanese Forest Society Congress  118-  (0)  692  -692  2007  [Not refereed][Not invited]
  • Report on the FLUXNET synthesis workshop 2007
    Takagi, K, Lee D, Tamai, K  AsiaFlux Newsletter  21-  1  -4  2007  [Not refereed][Not invited]
  • Report on the AsiaFlux Training Course 2007
    Saigusa, N, Takagi, K, Lee, D, Yuta, S  AsiaFlux Newsletter  23-  1  -3  2007  [Not refereed][Not invited]
  • 用語解説:シンチロメータ
    高木 健太郎  北海道の農業気象  59-  21  -23  2007  [Not refereed][Not invited]
  • 森林管理技術情報データベースの開発
    高木健太郎, 小宮圭示, 柴田英昭  北方森林保全技術  25-  46  -55  2007  [Not refereed][Not invited]
  • 天然林択伐作業における木質未利用バイオマスの収集コスト
    及川正敏, 秋林幸男, 野村睦, 高木健太郎, 上浦達哉, 北條元, 高橋廣行, 小塚力, 坂井励, 笹賀一郎  日本林学会北海道支部論文集  55-  98  -100  2007  [Not refereed][Not invited]
  • デジタル空中三角測量による20線群状伐採跡地の時系列解析
    坂井励, 高木健太郎, 野村睦, 上浦達哉, 北條元, 高橋廣行, 小塚力, 米康充  北方森林保全技術  25-  1  -14  2007  [Not refereed][Not invited]
  • 森林における炭素循環機能に関する観測研究(中間報告)
    笹賀一郎, 高木健太郎, 藤沼康実, 水野真人  北海道電力総合研究所研究年報  38-7-  2007  [Not refereed][Not invited]
  • 長谷川祥樹, 深澤達矢, 平島邦人, 野々上沙織, 橘治国, 高橋正宏, 福澤加里部, 柴田英昭, 野村睦, 高木健太郎, 藤沼康実  環境化学討論会講演要旨集  15th-  126  -127  2006/06/19  [Not refereed][Not invited]
  • 江口則和, 森井紀子, 渡邊陽子, 上田龍四郎, 高木健太郎, 船田良, 日浦勉, 笹賀一郎, 小池孝良  日本森林学会大会学術講演集(CD-ROM)  117th-  PA39  2006/04/03  [Not refereed][Not invited]
  • 江口則和, 森井紀子, 上田龍四郎, 高木健太郎, 船田良, 日浦勉, 笹賀一郎, 小池孝良  日本生態学会大会講演要旨集  53rd-  188  2006/03/24  [Not refereed][Not invited]
  • Nomura Mutumi, Takagi Kentaro, Takahashi Hiroyuki, Hojo Hajime, Sasa Kaichiro, Fujinuma Yasumi  Preprints of the Annual Conference, Japanese Society of Snow and Ice  2006-  (0)  221  -221  2006  [Not refereed][Not invited]
  • Fukuzawa Karibu, Shibata Hideaki, Takagi Kentaro, Satoh Fuyuki, Koike Takayoshi, Sasa Kaichiro  The Japanese Forest Society Congress  117-  (0)  61  -61  2006  [Not refereed][Not invited]
  • 高木健太郎, 野村睦, 福澤加里部, 柴田英昭, 深澤達矢, 秋林幸男, 笹賀一郎, 小池孝良, 藤沼康実, 梁乃申, 小熊宏之, 米康充, 犬飼孔, 前林衛  炭素循環および温室効果ガス観測ワークショップ講演要旨集 平成18年  146  -147  2006  [Not refereed][Not invited]
  • Report on the AsiaFlux Training Course 2006.
    Saigusa, N, Takagi, K, Yuta, S, Hirata R  AsiaFlux Newsletter  20-  1  -2  2006  [Not refereed][Not invited]
  • 航空機LIDARを用いた樹高と森林蓄積量の評価
    高橋廣行, 高木健太郎, 野村睦, 北條元, 上浦達哉, 小塚力, 坂井励, 米康充, 福士亮太, 小熊宏之, 藤沼康実, 前林衛  日本林学会北海道支部論文集  54-  93  -95  2006  [Not refereed][Not invited]
  • PENシステム導入によるカラマツ植林地の連続分光計測
    小熊宏之, 井手玲子, 中路達郎, 藤沼康実, 高木健太郎  日本林学会北海道支部論文集  54-  85  -86  2006  [Not refereed][Not invited]
  • FACE(開放系大気CO2増加)に生育する落葉広葉樹の水分生理特性
    森井紀子, 江口則和, 船田良, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本林学会北海道支部論文集  54-  64  -66  2006  [Not refereed][Not invited]
  • FACE(開放系大気CO2増加)で生育した落葉広葉樹の光合成特性
    唐津一樹, 飛弾剛, 江口則和, 上田龍四郎, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本林学会北海道支部論文集  54-  61  -63  2006  [Not refereed][Not invited]
  • 高CO2環境下で生育したブナとウダイカンバの呼吸特性-開放系大気CO2増加(FACE)を用いた場合-
    飛弾剛, 唐津一樹, 江口則和, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本林学会北海道支部論文集  54-  58  -60  2006  [Not refereed][Not invited]
  • 高CO2環境下での冷温帯樹木の水利用特性の変化が葉柄の内部構造に与える影響
    江口則和, 森井紀子, 上田龍四郎, 船田良, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本林学会北海道支部論文集  54-  49  -51  2006  [Not refereed][Not invited]
  • 天塩研究林におけるバイオマス調査について
    小塚力, 野村睦, 高木健太郎, 上浦達哉, 北條元, 高橋廣行, 坂井励, 林業技能補佐員  北方森林保全技術  24-  1  -11  2006  [Not refereed][Not invited]
  • AsiaFlux Workshop 2005 (International Workshop on Advanced Flux Network and Flux Evaluation) 報告
    高木健太郎, 安田幸生  水文・水資源学会誌  19-  151  -155  2006  [Not refereed][Not invited]
  • AsiaFluxワークショップ2005 (4th AsiaFlux Workshop)の報告
    安田幸生, 高木健太郎  生物と気象  6-  11  -14  2006  [Not refereed][Not invited]
  • 第4回AsiaFluxワークショップ2005報告
    山本哲, 高木健太郎, 安田幸生, 三枝信子  天気  53-  (5)  23  -28  2006  [Not refereed][Not invited]
  • 江口則和, 唐津一樹, 網野真一, 上田龍四郎, 船田良, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本生態学会大会講演要旨集  52nd-  254  2005/03/27  [Not refereed][Not invited]
  • 高橋広行, 高木健太郎, 野村睦, 菅田定雄, 北条元, 浪花彰彦, 小塚力, 米康充, 小熊宏之, 藤沼康実  日本森林学会大会講演要旨集(CD-ROM)  116th-  (0)  1C08  -277  2005/03/20  [Not refereed][Not invited]
  • HIRAJIMA Kunito, HAMAYA Motohiro, TOBISAWA Takuya, FUKAZAWA Tatsuya, TACHIBANA Harukuni, FUKUZAWA Karibu, SHIBATA Hideaki, NOMURA Mutsu, TAKAGI Kentarou, FUJINUMA Yasumi  Doboku Gakkai Ronbunshuu G  13-  317  -322  2005  [Not refereed][Not invited]
    To understand the behavior of metals in forest area, we collected atmospheric aerosol, fallout and river water samples in every two weeks from June of 2002 to December of 2004 in the Teshio Experimental Forest (45°03'N, 142°07'E a. s. 1.66m). And all samples were analyzed by ICP-MS for metals, such as Fe, Al, Ti, Ba, Sr, Mn, Zn, Pb.<BR>Atmospheric concentrations of Fe, A1, Pb, Mn and Sr in both aerosols and fallouts increased in winter. However, the atmospheric Zn and Ba in aerosols increased during winter, but in the fallouts.<BR>In the event of rainfall, Ba, Sr and Mn concentrations in river water, those were mainly plant origin, were decreasing with increasing in the flow. On the contrary, Al and Ti. concentrations in the water, those were mainly soil origin, were increasing in the same period. As for Fe, also soil origin was decreasing in the period. In thaw season, Fe, Ba and Sr concentrations decreased with increasing in flow, however, Al and Zn concentrations increased. In comparison the annual output from the river water with the annual input from the fallouts. As for Al, Fe, Sr and Ba, the output exceeded the input. As for Zn and Pb, the input exceeded the output. As for Mn and Ti, the input and the output were nearly equal.
  • NOMURA Muutumi, Takahashi Hiroyuki, SUGATA Sadao, SASA Kaichiro, SHIBATA Hideaki, TAKAGI Kentaro, HOJO Hajime, ASHIYA Daitaro, NANIWA Akihiko, KOZUKA Chikara, FUJINUMA Yasumi  Preprints of the Annual Conference, Japanese Society of Snow and Ice  2005-  (0)  105  -105  2005  [Not refereed][Not invited]
  • Takagi Kentaro, Nomura Mutsumi, Shibata Hideaki, Fukuzawa Karibu, Sasa Kaichiro, Akibayashi Yukio, Satoh Fuyuki, Fujinuma Yasumi  The Japanese Forest Society Congress  116-  (0)  717  -717  2005  [Not refereed][Not invited]
  • 笹 賀一郎, 佐藤 冬樹, 柴田 英昭, 高木 健太郎, 高畠 守, 福井 富三, 藤戸 永志, 有倉 清美, 石田 亘生, 奥山 悟, 石井 正, 奥田 篤志, 福澤 加, 藤沼 康美, 犬飼 孔  日本森林学会大会発表データベース  116-  (0)  737  -737  2005  [Not refereed][Not invited]
  • 北海道北部天然林の炭素吸収能と便益の評価
    秋林幸男, 高木健太郎, 野村睦, 北條元, 菅田定雄, 柴田英昭, 福澤加里部, 吉田俊也, 小池孝良, 笹賀一郎, 藤沼康実, 前林衛  北方林業  57-  176  -179  2005  [Not refereed][Not invited]
  • KAYAMA Masazumi, NOMURA Mutsumi, SASA Kaichiro, KOIKE Takayoshi, KITAOKA Satoshi, WANG Wengie, CHOI Dongsu, JI Donghum, SUGATA Sadao, HOJYO Hajime, NANIWA Akihiko, TAKAGI Kentaro  Transactions of the Meeting in Hokkaido Branch of the Japanese Forest Society  53-  (0)  49  -51  2005  [Not refereed][Not invited]
  • Free Air CO2 Enrichment (FACE)により高CO2処理された落葉広葉樹稚樹の光合成特性とRubiscoの応答
    唐津一樹, 網野真一, 江口則和, 上田龍四郎, 高木健太郎, 小池孝良  日本林学会北海道支部論文集  53-  76  -78  2005  [Not refereed][Not invited]
  • FACE (Free Air CO2 Enrichment)を用いた高CO2濃度処理が落葉樹稚樹へ与える影響-成長と生理反応, 2年間の結果-
    江口則和, 唐津一樹, 上田龍四郎, 船田良, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本林学会北海道支部論文集  53-  73  -75  2005  [Not refereed][Not invited]
  • 航空機LIDARによる森林の計測
    高橋廣行, 高木健太郎, 野村睦, 北條元, 小塚力, 浪花彰彦, 菅田定雄, 藤沼康実, 小熊宏之, 米康充  北方森林保全技術  23-  1  -4  2005  [Not refereed][Not invited]
  • 江口則和, 上田龍四郎, 船田良, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本林学会大会学術講演集  115th-  212  2004/03/20  [Not refereed][Not invited]
  • NOMURA Mutumi, Takahashi Hiroyuki, Sugata Sadao, Sasa Kaiciro, Shibata Hideaki, Takagi Kentaro, HOJO Hajime, ASHIYA Daitaro, NANIWA Akihiko, Kozuka Chikara, Fujinuma Yasumi  Preprints of the Annual Conference, Japanese Society of Snow and Ice  2004-  (0)  58  -58  2004  [Not refereed][Not invited]
  • 開放系大気CO2増加実験(FACE)による落葉樹数種の成長応答
    江口則和, 船田良, 上田龍四郎, 高木健太郎, 日浦勉, 笹賀一郎, 小池孝良  日本林学会北海道支部論文集  52-  66  -68  2004  [Not refereed][Not invited]
  • カラマツ若齢林の炭素循環機能に関する観測研究プロジェクト
    菅田定雄, 高木健太郎, 北條元, 浪花彰彦, 高橋廣行, 小塚力, 野村睦, 杉下義幸, 芦谷大太郎, 秋林幸男, 林業技能補佐員  北方森林保全技術  22-  1  -5  2004  [Not refereed][Not invited]
  • 北海道北部針広混交林における皆伐施業が微気象および炭素・水循環に与える影響
    高木健太郎, 野村睦, 柴田英昭, 笹賀一郎, 秋林幸男, 佐藤冬樹, 小池孝良, 福澤加里部, 香山雅純, 藤沼康実, 前林衛  北方林業  56-  197  -200  2004  [Not refereed][Not invited]
  • 森林の炭素固定機能に配慮した環境林の造成の試み
    高木 健太郎  北方林業  56-  279  -282  2004  [Not refereed][Not invited]
  • 福澤 加里部, 柴田 英昭, 高木 健太郎, 佐藤 冬樹, 笹賀 一郎, 小池 孝良  根の研究 = Root research  12-  (4)  2003/12/19  [Not refereed][Not invited]
  • Naniwa Akihiko, Sugata Sadao, Hojyo Hajime, Takahashi Hiroyuki, Takagi Kentaro, Nomura Mutsumi, Sugishita Yoshiyuki, Shibata Hideaki, Akibayashi Yukio, Kayama Masazumi, Fukuzawa Karibu  Technical report for boreal forest conservation of the Hokkaido University Forests  21-  (21)  26  -30  2003/12  [Not refereed][Not invited]
  • A Watershed-Scale Experiment on the Carbon Cycle of a Larch Plantation "CC-LaG (Carbon Cycle and Larch Growth) Experiment"
    Takagi, K, Sasa, K, Koike, T, Maebayashi, M, Fujinuma, Y  AsiaFlux Newsletter  5-  4  -7  2003  [Not refereed][Not invited]
  • 森林伐採・育林などの森林施業が二酸化炭素吸収に与える影響を解明する-北海道大学天塩研究林における大規模野外実験-
    北條元, 高木健太郎, 笹賀一郎, 小池孝良, 秋林幸男, 野村睦, 柴田英昭, 吉田俊也, 杉下義幸, 菅田定雄, 小林信, 芦谷大太郎, 浪花彰彦, 福澤加里部, 藤沼安実, 高田雅之, 前林衛, 酒井一弘  北方林業  54-  245  -247  2002  [Not refereed][Not invited]
  • 観測結果のデータベース化. フラックス観測の最近の進歩
    高木 健太郎  日本農業気象学会フラックス観測・評価部会編  42  -47  2002  [Not refereed][Not invited]
  • 第9回日米セミナー:地球変動ワークショップ「陸域生態系における炭素循環マネージメント」報告
    高木健太郎, 小池孝良  北方林業  54-  15  -18  2002  [Not refereed][Not invited]
  • インターネット公開・利用型の森林情報データベースの開発
    高木健太郎, 小宮圭示, 柴田英昭, 藤戸永志, 市川一, 高畠守, 間宮春大  北方森林保全技術  19-  63  -68  2001  [Not refereed][Not invited]
  • 永久凍土地帯における温暖化物質フラックス観測-アラスカ(フェアバンクス、バロー)の観測サイトを訪ねて-
    間宮春大, 高木健太郎  北方森林保全技術  19-  45  -49  2001  [Not refereed][Not invited]
  • Photosynthetic capacity of hybrid larch and dwarf bamboo grown in the Teshio Experimental Forest located near the border between Russia and Japan
    Proceeding of International Workshop for Advanced Flux Network and Flux Evaluation  105  -108  2001  [Not refereed][Not invited]
  • Evaluation of annual budgets of CH4 and CO2 at a lotus paddy field in central Japan
    Proceeding of International Workshop for Advanced Flux Network and Flux Evaluation  165  -169  2001  [Not refereed][Not invited]
  • Seasonal changes in the photosynthetic capacity of Japanese larch trees planted on the Tomakomai National Forest, northern Japan
    Proceeding of International Workshop for Advanced Flux Network and Flux Evaluation  109  -112  2001  [Not refereed][Not invited]
  • Respiration of non-photosynthetic organs and forest soil of Japanese larch plantation and its contribution to CO2 flux estimation
    Proceeding of International Workshop for Advanced Flux Network and Flux Evaluation  119  -123  2001  [Not refereed][Not invited]
  • AsiaFluxワークショップ2000 (International Workshop for Advanced Flux Network and Flux Evaluation-Kick off meeting of AsiaFlux Network-)報告
    高木健太郎, 溝口康子, 鈴木智恵子  生物と気象  1-  23  -28  2001  [Not refereed][Not invited]
  • フラックス観測の展望
    高木 健太郎  北方森林保全技術  18-  43  -47  2000  [Not refereed][Not invited]
  • Agro-environment information database using WWW ""Ecosystem Database""
    HARAZONO Yoshinobu, KOMINE Masashi, TAKAGI Kentaro, KOMURO Hirokazu  Bulletin of the Computing Centre for Research in Agriculture, Forestry and Fishery Series B  B13-  1  -118  2000  [Refereed][Not invited]
  • K Takagi, T Tsuboya, H Takahashi  AGRICULTURAL AND FOREST METEOROLOGY  93-  (1)  71  -72  1999/01  [Not refereed][Not invited]
  • サロベツ湿原のササ群落とミズゴケ群落の蒸発散特性-植物個体の気孔制御の視点から-
    高木健太郎, 坪谷太郎, 井上京, 高橋英紀  北方林業  51-  185  -189  1999  [Not refereed][Not invited]
  • 用語解説・気孔抵抗とポロメータ
    高木 健太郎  北海道の農業気象  48-  54  -55  1996  [Not refereed][Not invited]

Research Grants & Projects

  • アジアの森林土壌有機炭素放出の温暖化影響とフィードバック効果に関する包括的研究
    Date (from‐to) : 2017 -2019 
    Author : 梁 乃申
  • 森林における炭素循環機能に関する観測研究
    Date (from‐to) : 2009 -2019 
    Author : 高木 健太郎
  • 寒冷積雪環境下における、樹木の地上部-地下部間の物質の伝達
    Date (from‐to) : 2016 -2018 
    Author : 高木 健太郎
  • 百mメッシュの空間解像度を目標とした、北方林の広域炭素収支評価手法の確立
    Date (from‐to) : 2014 -2016 
    Author : 高木 健太郎
  • 開放系オゾン付加施設で生育する冷温帯樹種の成長に及ぼす窒素沈着の影響解明と応用
    Date (from‐to) : 2014 -2016 
    Author : 小池 孝良
  • 北方森林生態系における大規模撹乱後の植生遷移にともなう炭素動態の変化
    Date (from‐to) : 2013 -2016 
    Author : 平野 高司
  • 中国大興安嶺森林-湿原生態系における水・熱および炭素・物質動態と山火事撹乱の影響
    Date (from‐to) : 2011 -2014 
    Author : 佐藤 冬樹
  • 日本における森林土壌有機炭素放出に及ぼす温暖化影響のポテンシャル評価に関する研究
    Date (from‐to) : 2010 -2014 
    Author : 梁 乃申
  • 開放系大気CO2増加環境での樹木等の光合成と木部生産機能のパラメータ化
    Date (from‐to) : 2009 -2013 
    Author : 小池 孝良
  • 長期的な温暖化操作が日本の森林土壌の炭素・窒素動態に及ぼす影響
    Date (from‐to) : 2010 -2012 
    Author : 高木 健太郎
  • 東アジアの森林生態系におけるエアロゾルの沈着量と動態の評価
    Date (from‐to) : 2008 -2012 
    Author : 松田 和秀
  • 東アジア陸域生態系における炭素動態の定量化のための日中韓研究ネットワークの構築
    Date (from‐to) : 2007 -2012 
    Author : 平野 高司
  • 根系評価もふくめた北方森林流域における炭素および窒素動態と森林変化の影響
    Date (from‐to) : 2009 -2011 
    Author : 笹 賀一郎
  • 土壌呼吸に及ぼす温暖化影響の実験的評価
    Date (from‐to) : 2007 -2009 
    Author : 梁 乃申
  • 北方林の水・炭素循環に関する研究
    Date (from‐to) : 2001 -2008 
    Author : 笹 賀一郎
  • 積雪期における森林生態系からの二酸化炭素放出メカニズムの解明
    Date (from‐to) : 2006 -2007 
    Author : 高木 健太郎
  • 開放系二酸化炭素増加処理をした落葉広葉樹の被食防衛物質の局在性の解明
    Date (from‐to) : 2006 -2007 
    Author : 小池 孝良
  • 極東アジア地域カラマツ林における炭素および物質動態と環境変化影響に関する研究
    Date (from‐to) : 2005 -2007 
    Author : 佐藤 冬樹
  • 大気CO2増加実験に基づく変動環境下での移行帯森林の持続的利用と動態予測
    Date (from‐to) : 2005 -2007 
    Author : 小池 孝良
  • 大規模野外実験による流域スケールでの北方林生態系動態の解明
    Date (from‐to) : 2004 -2006 
    Author : 笹 賀一郎
  • FACE(開放系CO2増加実験)で生育した落葉樹の蒸散速度の解明
    Date (from‐to) : 2004 -2005 
    Author : 小池 孝良
  • 森林流域における一酸化二窒素・メタンの吸収・放出とそれに及ぼす水文過程の影響
    Date (from‐to) : 2003 -2005 
    Author : 杉本 敦子
  • 不成績造林地に侵入した有用広葉樹の育成と林分CO2固定能の向上に関する研究
    Date (from‐to) : 2002 -2004 
    Author : 小池 孝良
  • 大気と北方森林生態系間におけるCO2交換過程の解明,定量評価,およびモデル化
    Date (from‐to) : 2001 -2004 
    Author : 平野 高司
  • 北方森林圏データベース
    Date (from‐to) : 2002 -2003 
    Author : 高木 健太郎
  • 森林・湿原・酪農草地が陸上-湖沼生態系の溶存物質動態に及ぼす影響
    Date (from‐to) : 2001 -2003 
    Author : 柴田 英昭
  • 地域規模の二酸化炭素排出・吸収量評価方法の開発
    Date (from‐to) : 2001 -2003 
    Author : 藤沼 康実
  • 北方森林生態系における林床植物の二酸化炭素吸収能に関する研究
    Date (from‐to) : 2001 -2002 
    Author : 高木 健太郎
  • 森林樹木・林冠におけるガス交換
    Date (from‐to) : 1999 -2001 
    Author : 小池 孝良
  • Water and carbon cycles in Northern forests
    Cooperative Research
    Date (from‐to) : 2001

Educational Activities

Committee Membership

  • 2017 - Today   Asia Pacific Journal of Atmospheric sciences   Editor
  • 2017 - Today   The society of Agricultural Meteorology of Japan   Director
  • 2017 - Today   The society of Agricultural Meteorology of Japan   Dupty editor-in-chief of Climate in Biosphere
  • 2014 -2015   The society of Agricultural Meteorology of Japan   Editor
  • 2009 -2010   The society of Agricultural Meteorology of Japan   Editor
  • 2003 -2007   The society of Agricultural Meteorology of Japan   Editor

Social Contribution

Social Contribution

Social Contribution

  • 地球の温暖化と森林土壌からの炭素の放出
    Date (from-to) : 2017/10/30-2017/10/30
    Role : Lecturer
    Sponser, Organizer, Publisher  : 北海道大学北方生物圏フィールド科学センター天塩研究林
  • 森の力・北の森の炭素循環~天塩大規模植林実験の10年~
    Date (from-to) : 2010/11/19
    Role : Lecturer
    Sponser, Organizer, Publisher  : 北海道大学北方生物圏フィールド科学センター天塩研究林、国立環境研究所地球環境研究センター、北海道電力株式会社総合研究所
  • カラマツ植樹と産官学共同研究の紹介
    Date (from-to) : 2003/10/28-2003/10/29
    Role : Lecturer
    Sponser, Organizer, Publisher  : 北海道大学北海道大学北方生物圏フィールド科学センター天塩研究林、国立環境研究所地球環境研究センター、北海道電力株式会社総合研究所

Media Coverage

  • 炭素フラックスの観測・伐採影響
    Date : 2009/02/23
    Program, newspaper magazine: NHK おはよう北海道
    Media report
  • 天塩研究林の研究紹介
    Date : 2009
    Program, newspaper magazine: 雑誌カイ (2009年Winter号)
  • 炭素フラックスの観測
    Date : 2007/06/12
    Program, newspaper magazine: 北海道放送 HANAテレビ
    Media report
  • 産官学共同研究紹介
    Date : 2006/03/15
    Program, newspaper magazine: 読売新聞(北海道)
  • 産官学共同研究紹介
    Date : 2004/05/21
    Program, newspaper magazine: 朝日新聞(北海道)
  • カラマツ植樹
    Date : 2003/12
    Program, newspaper magazine: 幌延町広報誌ほろのべの窓
  • カラマツ植樹
    Date : 2003/12
    Program, newspaper magazine: 地球環境研究センターニュース
  • カラマツ植樹
    Date : 2003/10/31
    Program, newspaper magazine: 日刊留萌
  • カラマツ植樹
    Date : 2003/10/31
    Program, newspaper magazine: 北海道新聞
  • カラマツ植樹
    Date : 2003/10/30
    Program, newspaper magazine: 朝日新聞(北海道)
  • 産官学共同研究開始
    Date : 2001/11/08
    Program, newspaper magazine: 北海道新聞
  • 産官学共同研究開始
    Date : 2001/11/01
    Program, newspaper magazine: 日本経済新聞(茨城)
  • 産官学共同研究開始
    Date : 2001/10/31
    Program, newspaper magazine: 日本経済新聞(北海道)
  • 産官学共同研究開始
    Date : 2001/10/31
    Program, newspaper magazine: 日本工業新聞
  • 産官学共同研究開始
    Date : 2001/10/31
    Program, newspaper magazine: 毎日新聞 (北海道)
  • 産官学共同研究開始
    Date : 2001/10/31
    Program, newspaper magazine: 読売新聞 (北海道)

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