Researcher Database

Tatsuro Nakaji
Field Science Center for Northern Biosphere Forest Research Station Uryu Experimental Forest
Associate Professor

Researcher Profile and Settings


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

Job Title

  • Associate Professor


Research funding number

  • 40391130

J-Global ID

Research Interests

  • リモートセンシング   生理生態機能   森林   Ecophysiology   Forest   Remote Sensing   

Research Areas

  • Life sciences / Plants: molecular biology and physiology
  • Life sciences / Ecology and environmental science
  • Environmental science/Agricultural science / Environmental policy and society
  • Environmental science/Agricultural science / Environmental impact assessment


  •        - 2002  Tokyo University of Agriculture and Technology

Association Memberships

  • American Geophysical Union   日本リモートセンシング学会   日本生態学会   日本森林学会   大気環境学会   

Research Activities

Published Papers

  • Izuki Endo, Miwa Kobatake, Natsuko Tanikawa, Tatsuro Nakaji, Mizue Ohashi, Naoki Makita
    Annals of Botany 128 (1) 59 - 71 0305-7364 2021/07/28 [Refereed][Not invited]
    Abstract Background and Aims Condensed tannin (CT) is an important compound in plant biological structural defence and for tolerance of herbivory and environmental stress. However, little is known of the role and location of CT within the fine roots of woody plants. To understand the role of CT in fine roots across diverse species of woody dicot, we evaluated the localization of CT that accumulated in root tissue, and examined its relationships with the stele and cortex tissue in cross-sections of roots in 20 tree species forming different microbial symbiotic groups (ectomycorrhiza and arbuscular mycorrhiza). Methods In a cool-temperate forest in Japan, cross-sections of sampled roots in different branching order classes, namely, first order, second to third order, fourth order, and higher than fourth order (higher order), were measured in terms of the length-based ratios of stele diameter and cortex thickness to root diameter. All root samples were then stained with ρ-dimethylaminocinnamaldehyde solution and we determined the ratio of localized CT accumulation area to the root cross-section area (CT ratio). Key Results Stele ratio tended to increase with increasing root order, whereas cortex ratio either remained unchanged or decreased with increasing order in all species. The CT ratio was significantly positively correlated to the stele ratio and negatively correlated to the cortex ratio in second- to fourth-order roots across species during the shift from primary to secondary root growth. Ectomycorrhiza-associated species mostly had a higher stele ratio and lower cortex ratio than arbuscular mycorrhiza-associated species across root orders. Compared with arbuscular mycorrhiza species, there was greater accumulation of CT in response to changes in the root order of ectomycorrhiza species. Conclusions Different development patterns of the stele, cortex and CT accumulation along the transition from root tip to secondary roots could be distinguished between different mycorrhizal associations. The CT in tissues in different mycorrhizal associations could help with root protection in specific branching orders during shifts in stele and cortex development before and during cork layer formation.
  • Large-scale ecological field data for satellite validation in deciduous forests and grasslands.
    Akitsu, T.K, Nakaji, T, Kobayashi, H, Okano, T, Honda, Y, Bayarsaikhan, U, Terigele, Hayashi, M, Hiura, T, Ide, R, Igarashi, S, Kajiwara, K, Kumikawa, S, Matsuoka, Y, Nakano, T, Nakano, T, Okuda, A, Sato, T, Tachiiri, K, Takahashi, Y, Uchida, J, Nishida-Nasahara, K
    Ecological Research DOI: 10.1111/1440-1703.12155.  2020/10 [Refereed]
  • 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]
  • Mioko Ataka, Lijuan Sun, Tatsuro Nakaji, Ayumi Katayama, Tsutom Hiura
    Tree physiology 2020/01/24 [Refereed][Not invited]
    In forest ecosystems, fine root respiration directly contributes to belowground carbon (C) cycling. Exudation from fine roots indirectly affects C cycling via enhanced microbial decomposition of soil organic matter. Although these root-derived C fluxes are essential components of belowground C cycling, how nitrogen (N) addition affects these fluxes and their correlations remains unclear. In this study, fine root exudation, respiration, and chemical/morphological traits were measured in a dominant canopy species, Quercus crispula, found in a cool temperate forest, the Tomakomai Experimental Forest (TOEF), Hokkaido University, which has undergone five-year N addition. Soil-dissolved organic carbon (DOC) was also measured in both bulk and rhizosphere soils to evaluate the impact of fine root exudation on soil C cycling. Compared to a control plot with no N treatment, fine roots in the N addition plot exhibited larger diameters and higher N concentrations, but lower specific root lengths (SRLs) and areas (SRAs). On a root-weight basis, respiration was not different between plots, but exudation was slightly higher under N addition. On a root-area basis, exudation was significantly higher in the N addition plot. Additionally, differences in DOC between rhizosphere and bulk soils were two times higher in the N addition plot than the control plot. Although fine root respiration was positively correlated with exudation in both the control and N addition plots, the ratio of exudation C to respiration C decreased after five-year N addition. N addition also affected absolute C allocation to fine root exudation and changed the C allocation strategy between exudation and respiration fluxes. These findings will help enhance predictions of belowground C allocation and C cycling under N-rich conditions in the future.
  • Natsuko Tanikawa, Tatsuro Nakaji, Hikari Yahara, Naoki Makita
    PLANT AND SOIL 445 (1-2) 469 - 481 0032-079X 2019/12 [Refereed][Not invited]
    Aims Visible and near-infrared spectral reflectance can be used to determine the chemical composition of soil and plant organs. However, previous research has not used this for fresh fine root systems of tree species. We aimed to explore the predictive ability of spectral reflectance relationships among fine-root morphological, anatomical, and chemical traits for 12 tree species in a temperate forest in Japan. Methods Intact fresh systems of fine root were imaged at 478-978 nm wavelengths (153 bands, 3.6 nm interval). Relationships between spectral reflectance and specific root length, root tissue density, branching intensity, stele/cortex ratio, and Ca concentration were analyzed at each spectral band. Results Reflectance peaked at around 920 nm across all species; however, reflectance magnitude at spectral regions of blue (478 nm), green (546 nm), red (648 nm), and near-infrared (847 nm) significantly differed among species. All variables measuring traits were significantly correlated with spectral reflectance only at specific wavelengths, but the strength of the correlation differed among wavelengths. Conclusion Spectral reflectance in visible-near-infrared regions for fresh intact root systems can evaluate the species-differences in fine root traits, and can predict fine root traits across species. Our findings facilitate a general assessment of root traits across tree species and will allow more accurate estimation of fine root functions.
  • Martin Volf, Petr Klimeš, Greg P. A. Lamarre, Conor M. Redmond, Carlo L. Seifert, Tomokazu Abe, John Auga, Kristina Anderson-Teixeira, Yves Basset, Saul Beckett, Philip T. Butterill, Pavel Drozd, Erika Gonzalez-Akre, Ondřej Kaman, Naoto Kamata, Benita Laird-Hopkins, Martin Libra, Markus Manumbor, Scott E. Miller, Kenneth Molem, Ondřej Mottl, Masashi Murakami, Tatsuro Nakaji, Nichola S. Plowman, Petr Pyszko, Martin Šigut, Jan Šipoš, Robert Tropek, George D. Weiblen, Vojtech Novotny
    PLOS ONE 14 (10) e0222119 - e0222119 2019/10/23 [Refereed][Not invited]
  • Satoshi N. Suzuki, Mioko Ataka, Ika Djukic, Tsutomu Enoki, Karibu Fukuzawa, Mitsuru Hirota, Takuo Hishi, Tsutom Hiura, Kazuhiko Hoshizaki, Hideyuki Ida, Akira Iguchi, Yasuo Iimura, Takeshi Ise, Tanaka Kenta, Yoshifumi Kina, Hajime Kobayashi, Yuji Kominami, Hiroko Kurokawa, Kobayashi Makoto, Michinari Matsushita, Rie Miyata, Hiroyuki Muraoka, Tatsuro Nakaji, Masahiro Nakamura, Shigeru Niwa, Nam J. Noh, Takanori Sato, Tatsuyuki Seino, Hideaki Shibata, Ryo O. Suzuki, Koichi Takahashi, Tomonori Tsunoda, Tasuhiro Ustumi, Kenta Watanabe
    Ecological Research 34 (5) 575 - 576 0912-3814 2019/09/01 [Refereed][Not invited]
    © 2019 The Ecological Society of Japan Litter and soil organic matter decomposition represents one of the major drivers of carbon and nutrient cycling in a given ecosystem; however, it also contributes to a significant production of relevant greenhouse gasses. The Japanese archipelago spans several biomes (boreal-temperate-subtropical) and covers a large range of elevations and ecosystem types. Hence, the comprehension of this fundamental biogeochemical process in diverse ecosystems is crucial to maintain their ecosystem services. In this article, we have provided data on plant leaf decomposition from 33 research sites across Japan. At each site, standard litter material with different decomposition rates, rooibos tea and green tea were incubated for 90 days between 2012 and 2016 and the remaining mass was recorded. In total, 1904 bags were used. In addition, supplementary measurements of environmental variables essential for the interpretation of the collected data, such as soil and vegetation, were recorded. Plot-level averages of the remaining mass rates of bag contents after incubation ranged 0.17–0.51 for green tea and 0.54–0.82 for rooibos tea. Continued monitoring will also provide important insights into the temporal dynamics of litter decomposition.
  • Limitation in the Photosynthetic Acclimation to High Temperature in Canopy Leaves of Quercus serrata
    Daisuke P Yamaguchi, Dai Mishima, Kozue Nakamura, Junji Sano, Tatsuro Nakaji, Tsutom Hiura, Kouki Hikosaka
    Frontiers in Forests and Global Change 2 19  2019/05 [Refereed][Not invited]
  • Tomoko Akitsu, Kenlo Nishida Nasahara, Tatsuro Nakaji, Hajime Kobayashi, Tetsuo Okano, Nobuko Saigusa, Masato Hayashi, Reiko Ide, Yoshiaki Honda, Koji Kajiwara, Kaoru Tachiiri, Hideki Kobayashi, Kazuho Matsumoto, Toshiyuki Kobayashi
    To validate terrestrial ecological products of the Global Change Observation Mission-Climate (GCOM-C) satellite, a large-scale ecological observation project "JAXA Super Sites 500" was initiated. The project's purpose is to obtain the representative leaf area index (LAI), above-ground biomass (AGB), and fraction of absorbed PAR (fAPAR) in the satellite footprint scale. This study aimed to determine the appropriate observation methods in the satellite scale for the target land-cover types such as a deciduous broad-leaved forest, evergreen/deciduous needle-leaved forests, and a grassland. As a result of the comparative observations, a combination method using litter-traps and LAI-2200 was adopted as the LAI observation in a forest, a tree census method was adopted as the AGB observation in a forest, and a clipping method was adopted as the AGB and LAI observations in a grassland. LAI, AGB, and fAPAR were observed and were used to validate the GCOM-C terrestrial ecological products.
  • Kao Inoue, Hideaki Shibata, Toshiya Yoshida, Tatsuro Nakaji, Hiroyuki Obanawa, Akira Kato
    Jpn. J. For. Environ. 61 (1) 1 - 13 0388-8673 2019 [Refereed][Not invited]
  • Plant constituents affecting food selection by Sika deer.
    Agetsuma, N, Agetsuma-Yanagihara, Y, Takafumi, H, Nakaji, T
    The Journal of Wildlife Management 83 669 - 678 2019 [Refereed][Not invited]
  • Nakaji, T, Oguma, H, Nakamura, M, Kachina, P, Asanok, L, Marod, D, Aiba, M, Kurokawa, H, Kosugi, Y, Rahman Kassim, A, Hiura, T
    Remote Sensing of Environment 233 0034-4257 2019 [Refereed][Not invited]
    To elucidate the potential of hyperspectral remote sensing for estimating the functional leaf traits in East Asian forests, we investigated the utility of leaf spectroscopy and partial least square regression (PLSR) models for 141 tree species distributed widely across cool temperate to tropical climate zones in the Pacific region. In 14 forests in Japan, Thailand, and Malaysia, leaf samples at various developmental stages (young, mature, and senescent) were collected from two plant functional types (deciduous and evergreen species). The target leaf traits were leaf mass per unit area and concentrations of nitrogen (N), carbon (C), total phenol, cellulose, and lignin. The leaf reflectance at visible-short wave infrared spectral reflectance from 400 nm to 2395 nm was measured at 3-10-nm intervals (351 bands) using a spectral radiometer. First, we compared the performance of the PLSR models in terms of dry mass (DM)-based concentration and leaf area (LA)-based concentration. Then, we investigated the applicability of the models based on the different plant functional types and leaf developmental stages of the training dataset. Finally, we evaluated the minimum number of spectral bands needed for stable performance of the PLSR model by changing the used bands in accordance with the variable importance of projection (VIP) and equal interval resampling.The coefficient of determination (R-2) was higher and the normalized root mean square error (NRMSE) tended to be lower for all chemical trait concentrations expressed based on LA than for those based on DM, except for the case of leaf N. Plant functional type in the training data affected the applicability of the estimation model strongly. The estimation error increased when the functional type in the training dataset differed from that of the target tree species. In the PLSR model calibrated using datasets of evergreen tree species, the NRMSEs of the six traits were 8.0-12.6% for evergreen tree species but 10.4-21.1% for deciduous tree species. A similar trend was observed in the model calibrated for deciduous tree species. The model calibrated using both functional types showed intermediate accuracy for both types of tree species (NRMSE = 5.3-13.5%). The developmental stage of training data also affected the model performance, and the model calibrated using all of the stages showed better estimation accuracies for young and senescent leaves than the model calibrated from the data of mature leaves alone.The equal interval resampling provided better estimation accuracy than the case using the threshold of the VIP value although the model performance tended to be diminished with the reduction of input waveband in both methods. Using at least 104 bands with equal interval removal at a 20-nm interval confers similar performance of the PLSR model compared to the model with full wavebands. This study is the first to describe the potential of leaf spectroscopy for trait estimation of East Asian forest tree species, and our findings suggest that training datasets of typical functional types and varied developmental stages are important for estimation of leaf traits through the several biomes distributed widely in East Asia.
  • Arjasakusuma, S, Yamaguchi, Y, Nakaji, T, Kosugi, Y, Shamsuddin, S.-A, Lion, M
    European Journal of Remote Sensing 51 863 - 877 2018/07 [Refereed][Not invited]
  • Ika Djukic, Sebastian Kepfer-Rojas, Inger Kappel Schmidt, Klaus Steenberg Larsen, Claus Beier, Björn Berg, Kris Verheyen, Adriano Caliman, Alain Paquette, Alba Gutiérrez-Girón, Alberto Humber, Alejandro Valdecantos, Alessandro Petraglia, Heather Alexander, Algirdas Augustaitis, Amélie Saillard, Ana Carolina Ruiz Fernández, Ana I. Sousa, Ana I. Lillebø, Anderson da Rocha Gripp, André-Jean Francez, Andrea Fischer, Andreas Bohner, Andrey Malyshev, Andrijana Andrić, Andy Smith, Angela Stanisci, Anikó Seres, Anja Schmidt, Anna Avila, Anne Probst, Annie Ouin, Anzar A. Khuroo, Arne Verstraeten, Arely N. Palabral-Aguilera, Artur Stefanski, Aurora Gaxiola, Bart Muys, Bernard Bosman, Bernd Ahrends, Bill Parker, Birgit Sattler, Bo Yang, Bohdan Juráni, Brigitta Erschbamer, Carmen Eugenia Rodriguez Ortiz, Casper T. Christiansen, E. Carol Adair, Céline Meredieu, Cendrine Mony, Charles A. Nock, Chi-Ling Chen, Chiao-Ping Wang, Christel Baum, Christian Rixen, Christine Delire, Christophe Piscart, Christopher Andrews, Corinna Rebmann, Cristina Branquinho, Dana Polyanskaya, David Fuentes Delgado, Dirk Wundram, Diyaa Radeideh, Eduardo Ordóñez-Regil, Edward Crawford, Elena Preda, Elena Tropina, Elli Groner, Eric Lucot, Erzsébet Hornung, Esperança Gacia, Esther Lévesque, Evanilde Benedito, Evgeny A. Davydov, Evy Ampoorter, Fabio Padilha Bolzan, Felipe Varela, Ferdinand Kristöfel, Fernando T. Maestre, Florence Maunoury-Danger, Florian Hofhansl, Florian Kitz, Flurin Sutter, Francisco Cuesta, Francisco de Almeida Lobo, Franco Leandro de Souza, Frank Berninger, Franz Zehetner, Georg Wohlfahrt, George Vourlitis, Geovana Carreño-Rocabado, Gina Arena, Gisele Daiane Pinha, Grizelle González, Guylaine Canut, Hanna Lee, Hans Verbeeck, Harald Auge, Harald Pauli, Hassan Bismarck Nacro, Héctor A. Bahamonde, Heike Feldhaar, Heinke Jäger, Helena C. Serrano, Hélène Verheyden, Helge Bruelheide, Henning Meesenburg, Hermann Jungkunst, Hervé Jactel, Hideaki Shibata, Hiroko Kurokawa, Hugo López Rosas, Hugo L. Rojas Villalobos, Ian Yesilonis, Inara Melece, Inge Van Halder, Inmaculada García Quirós, Isaac Makelele, Issaka Senou, István Fekete, Ivan Mihal, Ivika Ostonen, Jana Borovská, Javier Roales, Jawad Shoqeir, Jean-Christophe Lata, Jean-Paul Theurillat, Jean-Luc Probst, Jess Zimmerman, Jeyanny Vijayanathan, Jianwu Tang, Jill Thompson, Jiří Doležal, Joan-Albert Sanchez-Cabeza, Joël Merlet, Joh Henschel, Johan Neirynck, Johannes Knops, John Loehr, Jonathan von Oppen, Jónína Sigríður Þorláksdóttir, Jörg Löffler, José-Gilberto Cardoso-Mohedano, José-Luis Benito-Alonso, Jose Marcelo Torezan, Joseph C. Morina, Juan J. Jiménez, Juan Dario Quinde, Juha Alatalo, Julia Seeber, Jutta Stadler, Kaie Kriiska, Kalifa Coulibaly, Karibu Fukuzawa, Katalin Szlavecz, Katarína Gerhátová, Kate Lajtha, Kathrin Käppeler, Katie A. Jennings, Katja Tielbörger, Kazuhiko Hoshizaki, Ken Green, Lambiénou Yé, Laryssa Helena Ribeiro Pazianoto, Laura Dienstbach, Laura Williams, Laura Yahdjian, Laurel M. Brigham, Liesbeth van den Brink, Lindsey Rustad, Lipeng Zhang, Lourdes Morillas, Lu Xiankai, Luciana Silva Carneiro, Luciano Di Martino, Luis Villar, Maaike Y. Bader, Madison Morley, Marc Lebouvier, Marcello Tomaselli, Marcelo Sternberg, Marcus Schaub, Margarida Santos-Reis, Maria Glushkova, María Guadalupe Almazán Torres, Marie-Andrée Giroux, Marie-Anne de Graaff, Marie-Noëlle Pons, Marijn Bauters, Marina Mazón, Mark Frenzel, Markus Didion, Markus Wagner, Maroof Hamid, Marta L. Lopes, Martha Apple, Martin Schädler, Martin Weih, Matteo Gualmini, Matthew A. Vadeboncoeur, Michael Bierbaumer, Michael Danger, Michael Liddell, Michael Mirtl, Michael Scherer-Lorenzen, Michal Růžek, Michele Carbognani, Michele Di Musciano, Michinari Matsushita, Miglena Zhiyanski, Mihai Pușcaș, Milan Barna, Mioko Ataka, Mo Jiangming, Mohammed Alsafran, Monique Carnol, Nadia Barsoum, Naoko Tokuchi, Nico Eisenhauer, Nicolas Lecomte, Nina Filippova, Norbert Hölzel, Olga Ferlian, Oscar Romero, Osvaldo B. Pinto, Pablo Peri, Paige Weber, Pascal Vittoz, Pavel Dan Turtureanu, Peter Fleischer, Peter Macreadie, Peter Haase, Peter Reich, Petr Petřík, Philippe Choler, Pierre Marmonier, Priscilla Muriel, Quentin Ponette, Rafael Dettogni Guariento, Rafaella Canessa, Ralf Kiese, Rebecca Hewitt, Regin Rønn, Rita Adrian, Róbert Kanka, Robert Weigel, Roberto Cazzolla Gatti, Rodrigo Lemes Martins, Romain Georges, Rosa Isela Meneses, Rosario G. Gavilán, Sabyasachi Dasgupta, Sally Wittlinger, Sara Puijalon, Sarah Freda, Satoshi Suzuki, Sean Charles, Sébastien Gogo, Simon Drollinger, Simone Mereu, Sonja Wipf, Stacey Trevathan-Tackett, Stefan Löfgren, Stefan Stoll, Stefan Trogisch, Stefanie Hoeber, Steffen Seitz, Stephan Glatzel, Sue J. Milton, Sylvie Dousset, Taiki Mori, Takanori Sato, Takeshi Ise, Takuo Hishi, Tanaka Kenta, Tatsuro Nakaji, Thaisa Sala Michelan, Thierry Camboulive, Thomas J. Mozdzer, Thomas Scholten, Thomas Spiegelberger, Thomas Zechmeister, Till Kleinebecker, Tsutom Hiura, Tsutomu Enoki, Tudor-Mihai Ursu, Umberto Morra di Cella, Ute Hamer, Valentin H. Klaus, Vanessa Mendes Rêgo, Valter Di Cecco, Verena Busch, Veronika Fontana, Veronika Piscová, Victoria Carbonell, Victoria Ochoa, Vincent Bretagnolle, Vincent Maire, Vinicius Farjalla, Wenjun Zhou, Wentao Luo, William H. McDowell, Yalin Hu, Yasuhiro Utsumi, Yuji Kominami, Yulia Zaika, Yury Rozhkov, Zsolt Kotroczó, Zsolt Tóth
    Science of The Total Environment 628-629 1369 - 1394 0048-9697 2018/07 [Refereed][Not invited]
    Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from -9 to +26 degrees C MAT and from 60 to 3113 mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained <0.5% of the variation for Green tea and 5% for Rooibos tea, and was of significance only under unfavorable decomposition conditions (i.e. xeric versus mesic environments). When the data were aggregated at the biome scale, climate played a significant role on decomposition of both litter types (explaining 64% of the variation for Green tea and 72% for Rooibos tea). No significant effect of land-use on early stage litter decomposition was noted within the temperate biome. Our results indicate that multiple drivers are affecting early stage litter mass loss with litter quality being dominant. In order to be able to quantify the relative importance of the different drivers over time, long-term studies combined with experimental trials are needed. (C) 2018 Elsevier B.V. All rights reserved.
  • 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) 1 - 2 1440-1703 2018/06/26 [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.
  • 北大研究林の強みを活かした教育研究の充実に向けて―平成27年度報告会総合討論―
    中路達郎, 岸田治, 内海俊介, 福澤加里部, 小林真, 伊藤悠也, 間宮春大, 芦谷大太郎, 上浦達哉
    北方森林保全技術 34 43 - 47 2017 [Not refereed][Not invited]
  • Yutaka Okuzaki, Koji Mochida, Shin Nagai, Tatsuro Nakaji, Hiroyuki Oguma
    Japanese Journal of Ecology 67 (1) 41 - 56 0021-5007 2017 [Refereed][Not invited]
    © 2017, Tohoku University. All rights reserved. Sunlight is a mixture of electromagnetic radiation at wavelengths ranging from 300 to 2500 nm at the surface of the earth. Interactions between electromagnetic waves and matter change with the wavelength. Ultraviolet and visible light (330-760 nm) is absorbed by photoreceptor proteins in the eyes of animals, providing them with ‘visible’ information. Photosynthetically active radiation (400-700 nm) is essential for many plants, while near-infrared light (700-2500 nm) is absorbed by water and organic compounds. Therefore, measurements of the features of these reflection spectra can be useful for studying both the vision of animals and physiological functions of plants. Spectrometers are used to measure the electromagnetic spectrum and conventionally most have been large instruments installed indoors. Recent technological developments have produced handheld spectrometers that can measure the spectrum at a pinpoint anywhere. Moreover, imaging spectrometers, which spectrally disperse the incident light at each pixel, continue to be improved and can provide spectroscopic images at any scale. This review explains spectrometry and introduces ecological studies using the latest spectrometers. The recent application of spectrometry to field studies should reveal new relationships between organisms and light.
  • Daisuke P. Yamaguchi, Tatsuro Nakaji, Tsutom Hiura, Kouki Hikosaka
    TREE PHYSIOLOGY 36 (10) 1283 - 1295 0829-318X 2016/10 [Refereed][Not invited]
    The effects of warming on the temperature response of leaf photosynthesis have become an area of major concern in recent decades. Although growth temperature (GT) and day length (DL) affect leaf gas exchange characteristics, the way in which these factors influence the temperature dependence of photosynthesis remains uncertain. We established open-top canopy chambers at the canopy top of a deciduous forest, in which average daytime leaf temperature was increased by 1.0aEuro...A degrees C. We conducted gas exchange measurements for the canopy leaves of deciduous trees exposed to artificial warming during different seasons. The carbon dioxide assimilation rate at 20aEuro...A degrees C (A(20)) was not affected by warming, whereas that at 25aEuro...A degrees C (A(25)) tended to be higher in leaves exposed to warming. Warming increased the optimal temperature of photosynthesis by increasing the activation energy for the maximum rate of carboxylation. Regression analysis indicated that both GT and DL strongly influenced gas exchange characteristics. Sensitivity analysis revealed that DL affected A without obvious effects on the temperature dependence of A, whereas GT almost maintained constant A(20) and strongly influenced the temperature dependence. These results indicate that GT and DL have different influences on photosynthesis; GT and DL affect the 'slope' and intercept' of the temperature dependence of photosynthesis, respectively.
  • Evgenios Agathokleous, Makoto Watanabe, Norikazu Eguchi, Tatsuro Nakaji, Fuyuki Satoh, Takayoshi Koike
    WATER AIR AND SOIL POLLUTION 227 (6) 187  0049-6979 2016/06 [Refereed][Not invited]
    We examined the root production of a set of Fagus crenata (Siebold's beech) saplings grown in an infertile immature volcanic ash soil (VA) and another set in a fertile brown forest soil (BF) with both sets exposed to elevated CO2. After the saplings had been exposed to ambient (370-390 mu mol mol(-1)) or elevated (500 mu mol mol(-1)) CO2, during the daytime, for 11 growing seasons, the root systems were excavated. Elevated CO2 boosted the total root production of saplings grown in VA and abolished the negative effect of VA under ambient CO2, but there was no significant effect of elevated CO2 on saplings grown in BE These results indicate the projected elevated CO2 concentrations may have a different impact in regions with different soil fertility while in regions with VA, a higher net primary production is expected. In addition, we observed large elevated CO2-induced fine-root production and extensive foraging strategy of saplings in both soils, a phenomenon that may partly (a) adjust the biogeochemical cycles of ecosystems, (b) form their response to global change, and (c) increase the size and/or biodiversity of soil fauna. We recommend that future researches consider testing a soil with a higher degree of infertility than the one we tested.
  • Xiaona Wang, Saki Fujita, Tatsuro Nakaji, Makoto Watanabe, Fuyuki Satoh, Takayoshi Koike
    TREES-STRUCTURE AND FUNCTION 30 (2) 363 - 374 0931-1890 2016/04 [Refereed][Not invited]
    Increased atmospheric CO2 usually enhances photosynthetic ability and growth of trees. To understand how increased CO2 affects below-ground part of trees under varied soil condition, we investigated the responses of the fine root (diameter < 2 mm) dynamics of Japanese white birch (Betula platyphylla var. japonica) which was planted in 2010. The three-year-old birch seedlings were grown in four experimental treatments comprising two levels of CO2, i.e., ambient: 380-390 and elevated: 500 mu mol mol(-1), in combination with two kinds of soil: brown forest (BF) soil and volcanic ash (VA) soil which has few nutrients. The growth and turnover of fine roots were measured for 3 years (2011-2013) using the Mini-rhizotron. In the first observation year, live fine root length (standing crop) in BF soil was not affected by CO2 treatment, but it was reduced by the elevated CO2 from the second observation year. In VA soil, live fine root length was reduced by elevated CO2 for all 3 years. Fine root turnover tended to decrease under elevated CO2 compared with ambient in both soil types during the first and second observation years. Turnover of fine root production and mortality was also affected by the two factors, elevated CO2 and different soil types. Median longevity of fine root increased under elevated CO2, especially in VA soil at the beginning, and a shorter fine root lifespan appeared after 2 years of observation (2011-2012). These results suggest that elevated CO2 does not consistently stimulate fine root turnover, particularly during the plant seedlings stage, as it may depend on the costs and benefits of constructing and retaining roots. Therefore, despite the other uncontrollable environment factors, carbon sequestration to the root system may be varied by CO2 treatment period, soil type and plant age.
  • Evgenios Agathokleous, Makoto Watanabe, Tatsuro Nakaji, Xiaona Wang, Fuyuki Satoh, Takayoshi Koike
    TREES-STRUCTURE AND FUNCTION 30 (2) 353 - 362 0931-1890 2016/04 [Refereed][Not invited]
    We evaluated the root response to elevated CO2 fumigation of 3 birches (Betula sp.) and 1 deciduous oak (Quercus sp.) grown in immature volcanic ash soil (VA) or brown forest soil (BF). VA is a nutrient-poor, phosphorus-impoverished soil, broadly distributed in northern Japan. Each species had been exposed to either ambient (375-395 mu mol mol(-1)) (aCO(2)) or elevated (500 mu mol mol(-1)) (eCO(2)) CO2 during the daytime (more than 70 mu mol m(-2) s(-1)) over 4 growing seasons. The results suggest that eCO(2) did not cause an increase in total root production when the community had grown in fertile BF soil, however, it did cause a large increase when the community was grown in infertile VA soil. Yet, carbon allocation to plant roots was not affected by eCO(2) in either the BF or VA soils. Rhizo-morphogenesis appeared to occur to a greater extent under eCO(2). It seems that the saplings developed a massive amount of fine roots under the VA and eCO(2) conditions. Unexpectedly, eCO(2) resulted in a larger total root mass when the community was grown in VA soil than when grown in BF soil (eCO(2) x VA vs. eCO(2) x BF). These results may hint to a site-specific potential of communities to sequester future atmospheric carbon. The growing substance of plants is an important factor which root response to eCO(2) depends on, however, further studies are needed for a better understanding.
  • Nam-Jin Noh, Masatoshi Kuribayashi, Taku M. Saitoh, Tatsuro Nakaji, Masahiro Nakamura, Tsutom Hiura, Hiroyuki Muraoka
    ECOSYSTEMS 19 (3) 504 - 520 1432-9840 2016/04 [Refereed][Not invited]
    How global warming will affect soil respiration (R (S)) and its source components is poorly understood despite its importance for accurate prediction of global carbon (C) cycles. We examined the responses of R (S), heterotrophic respiration (R (H)), autotrophic respiration (R (A)), nitrogen (N) availability, and fine-root biomass to increased temperature in an open-field soil warming experiment. The experiment was conducted in a cool-temperate deciduous forest ecosystem in northern Japan. As this forest is subjected to strong temporal variation in temperature, on scales ranging from daily to seasonal, we also investigated the temporal variation in the effects of soil warming on R (S), R (H), and R (A). Soil temperature was continuously elevated by about 4.0A degrees C from 2007 to 2014 using heating wires buried in the soil, and we measured soil respiratory processes in all four seasons from 2012 to 2014. Soil warming increased annual R (S) by 32-45%, but the magnitude of the increase was different between the components: R (H) and R (A) were also stimulated, and increased by 39-41 and 17-18%, respectively. Soil N availability during the growing season and fine-root biomass were not remarkably affected by the warming treatment. We found that the warming effects varied seasonally. R (H) increased significantly throughout the year, but the warming effect showed remarkable seasonal differences, with the maximum stimulation in the spring. This suggests that warmer spring temperature will produce a greater increase in CO2 release than warmer summer temperatures. In addition, we found that soil warming reduced the temperature sensitivity (Q (10)) of R (S). Although the Q (10) of both R (H) and R (A) tended to be reduced, the decrease in the Q (10) of R (S) was caused mainly by a decrease in the response of R (A) to warming. These long-term results indicate that a balance between the rapid and large response of soil microbes and the acclimation of plant roots both play important roles in determining the response of R (S) to soil warming, and must be carefully considered to predict the responses of soil C dynamics under future temperature conditions.
  • Masahiro Nakamura, Tatsuro Nakaji, Onno Muller, Tsutom Hiura
    Oikos 124 (8) 1071 - 1077 0030-1299 2015/08 [Refereed][Not invited]
  • Tomoko Akitsu, Kenlo Nishida Nasahara, Hideki Kobayashi, Nobuko Saigusa, Masato Hayashi, Tatsuro Nakaji, Hajime Kobayashi, Tetsuo Okano, Yoshiaki Honda
    2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS) 3866 - 3869 2153-6996 2015 [Refereed][Not invited]
    The global leaf area index (LAI) and above-ground biomass (AGB) are essential parameters in ecology and hydrology. Therefore, datasets derived from satellite remote sensing are needed. To assess data accuracy, insitu datasets of LAI and AGB measured at a large scale (that of satellite footprints) are desired. However, such data are rarely available. Therefore, we initiated the project "JAXA Super Sites 500" to obtain in-situ LAI and AGB data at the 500 m x 500 m scale. We established four observation sites in Japan and carried out pilot studies at two sites in 2014. This study aimed to examine an observation method at this scale and to evaluate the data quality. At the Fujihokuroku site, the mean LA! was 1.89 (LAI-2000), 2.85 (fish-eye camera), and 2.14 (tree census within a partial area). The mean AGB was 117 t/ha (Bitterlich's method) and 126 t/ha (tree census within a partial area).
  • L. Wingate, J. Ogee, E. Cremonese, G. Filippa, T. Mizunuma, M. Migliavacca, C. Moisy, M. Wilkinson, C. Moureaux, G. Wohlfahrt, A. Hammerle, L. Hoertnagl, C. Gimeno, A. Porcar-Castell, M. Galvagno, T. Nakaji, J. Morison, O. Kolle, A. Knohl, W. Kutsch, P. Kolari, E. Nikinmaa, A. Ibrom, B. Gielen, W. Eugster, M. Balzarolo, D. Papale, K. Klumpp, B. Koestner, T. Gruenwald, R. Joffre, J. -M. Ourcival, M. Hellstrom, A. Lindroth, C. George, B. Longdoz, B. Genty, J. Levula, B. Heinesch, M. Sprintsin, D. Yakir, T. Manise, D. Guyon, H. Ahrends, A. Plaza-Aguilar, J. H. Guan, J. Grace
    BIOGEOSCIENCES 12 (20) 5995 - 6015 1726-4170 2015 [Refereed][Not invited]
    Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant development stages and their response to climate and management practices are crudely represented in land surface models. As visual observations of phenology are laborious, there is a need to supplement long-term observations with automated techniques such as those provided by digital repeat photography at high temporal and spatial resolution. We present the first synthesis from a growing observational network of digital cameras installed on towers across Europe above deciduous and evergreen forests, grasslands and croplands, where vegetation and atmosphere CO2 fluxes are measured continuously. Using colour indices from digital images and using piecewise regression analysis of time series, we explored whether key changes in canopy phenology could be detected automatically across different land use types in the network. The piecewise regression approach could capture the start and end of the growing season, in addition to identifying striking changes in colour signals caused by flowering and management practices such as mowing. Exploring the dates of green-up and senescence of deciduous forests extracted by the piecewise regression approach against dates estimated from visual observations, we found that these phenological events could be detected adequately (RMSE < 8 and 11 days for leaf out and leaf fall, respectively). We also investigated whether the seasonal patterns of red, green and blue colour fractions derived from digital images could be modelled mechanistically using the PROSAIL model parameterised with information of seasonal changes in canopy leaf area and leaf chlorophyll and carotenoid concentrations. From a model sensitivity analysis we found that variations in colour fractions, and in particular the late spring 'green hump' observed repeatedly in deciduous broadleaf canopies across the network, are essentially dominated by changes in the respective pigment concentrations. Using the model we were able to explain why this spring maximum in green signal is often observed out of phase with the maximum period of canopy photosynthesis in ecosystems across Europe. Coupling such quasi-continuous digital records of canopy colours with co-located CO2 flux measurements will improve our understanding of how changes in growing season length are likely to shape the capacity of European ecosystems to sequester CO2 in the future.
  • Rieko Urakawa, Nobuhito Ohte, Hideaki Shibata, Ryunosuke Tateno, Takuo Hishi, Keitaro Fukushima, Yoshiyuki Inagaki, Keizo Hirai, Tomoki Oda, Nobuhiro Oyanagi, Makoto Nakata, Hiroto Toda, Tanaka Kenta, Karibu Fukuzawa, Tsunehiro Watanabe, Naoko Tokuchi, Tatsuro Nakaji, Nobuko Saigusa, Yukio Yamao, Asami Nakanishi, Tsutomu Enoki, Shin Ugawa, Atsushi Hayakawa, Ayumi Kotani, Megumi Kuroiwa, Kazuo Isobe
    ECOLOGICAL RESEARCH 30 (1) 1 - 2 0912-3814 2015/01 [Refereed][Not invited]
    This data paper provides some biogeochemical nitrogen (N) properties and related chemical properties of forest soils from 39 sites throughout the Japanese archipelago. The data set was collected and analyzed under the GRENE (Green Network of Excellence) environmental information project and the ReSIN (Regional and comparative Soil Incubation study on Nitrogen dynamics in forest ecosystems) project. The sites cover 44A degrees 20'N to 26A degrees 50'N and the climate ranges from cool-temperate zone to subtropical zone. At each site, litter on forest floor and soil samples (three or four layers to 50 cm depth) were collected between August and November in 2010-2013 from five soil profiles. From the litter layer samples, the stocks and concentrations of total carbon (C) and N were measured. From the mineral soil samples, bulk density, pH (H2O), total C and N concentrations, net and gross rates of N mineralization, nitrification and concentrations of water-soluble substances were measured. The measurements are relevant for other biogeochemical N studies in forest ecosystems and the data set provides basic information on the N pool and fluxes with related chemical properties of forest soils across the Japanese archipelago. The average rates of net and gross N transformation at 20 A degrees C across the sites were 0.26 +/- A 0.47 mgN kg(-1) soil d(-1) for net N mineralization, 0.25 +/- A 0.45 mgN kg(-1) soil d(-1) for net nitrification, 4.06 +/- A 0.47 mgN kg(-1) soil d(-1) for gross N mineralization, and 1.03 +/- A 1.29 mgN kg(-1) soil d(-1) for gross nitrification (average +/- A SD).
  • Tatsuro Nakaji, Yoshiko Kosugi, Satoru Takanashi, Kaoru Niiyama, Shoji Noguchi, Makoto Tani, Hiroyuki Oguma, Abdul Rahim Nik, Abd Rahman Kassim
    REMOTE SENSING OF ENVIRONMENT 150 82 - 92 0034-4257 2014/07 [Refereed][Not invited]
    In the search for a better method of estimating the light-use efficiency (LUE) of evergreen tropical rainforests, we employed remotely sensed spectral vegetation indices (VIs) to monitor both CO2 flux and canopy spectral reflectance over 3 years in a lowland dipterocarp forest in Peninsular Malaysia. We investigated the sensitivity of five VIs calculated from spectral reflectance: the photochemical reflectance index (PRI), the canopy chlorophyll index (CCI), the normalized difference vegetation index (NDVI), the enhanced vegetation index (EVI) and the water index (WI). During the monitoring period, clear seasonal variations were not found in LUE, the observed Vls or the phenological timing (particularly new leaf flush) of dominant dipterocarp trees. Although leaf phenology tended to correlate with variations in the CCI, the highest correlation coefficient among the relationships between WE and the VIs was observed in PRI (R = 0.341, n = 699). Among the relationships between LUE and meteorological factors, the strongest correlation was found between LUE and vapor pressure deficit (VPD; R = -0580). These results suggest that unseasonal variation in LUE would be more affected by water conditions than leaf phenology or green leaf mass, and that the PRI has lower sensitivity for direct estimation of LUE compared to VPD in this evergreen tropical rainforest. To improve the accuracy in estimating LUE, we examined the potential of combinational use of Vls and meteorological factors. Variable selection by stepwise multiple regression showed that the best variable combination for LUE estimation was the PR! and VPD (R = 0.612). The relative root mean square error (rRMSE) in the simple regression models using PR!, VPD and PRI x VPD, and the multiple regression model using PR! and VPD, was 22.5%, 19.4%, 19.0% and 18.7%, respectively. Based on these results, we concluded that (1) the estimation method solely based on the PRI as in the case of other temperate deciduous forests is not suitable in the tropical evergreen rainforest, and (2) the combinational use of the PRI and VPD offers one of the better models for estimating LUE in tropical evergreen rainforests. (C) 2014 Elsevier Inc. All rights reserved.
  • Takagi Rie, Makita Naoki, Nakaji Tatsuro, Katayama Ayumi, Kosugi Yoshiko, Hiura Tsutomu
    The Japanese Forest Society Congress 日本森林学会 125 751 - 751 2014 
    [in Japanese]
  • Nakaji, T, Oguma, H, Hiura, T
    Japanese Journal of Ecology 64 215 - 221 2014 [Refereed][Not invited]
  • Miki U. Ueda, Onno Muller, Masahiro Nakamura, Tatsuro Nakaji, Tsutom Hiura
    SOIL BIOLOGY & BIOCHEMISTRY 61 105 - 108 0038-0717 2013/06 [Refereed][Not invited]
    We report on the seasonal responses of soil nitrogen (N) pools to soil warming in a cool temperate forest where mild freeze-thaw cycles occur during winter. Artificial soil warming of 2-5 degrees C was implemented to prevent freezing, making it possible to evaluate the effects of soil freezing on soil characteristics. At control sites, the dissolved organic N and NH4-N pools were largest in winter. Soil warming decreased these solute pools to 17-25% of control levels during winter, but not in other seasons. These results confirm that soil freezing is the driving force of N dynamics during winter, and is easily lost by a few degrees of warming at this study site. The substantial reduction of solute N pools may reduce N availability in the cool temperate forest. (C) 2013 Elsevier Ltd. All rights reserved.
  • Sou N. Matsunaga, Onno Muller, Satoru Chatani, Masahiro Nakamura, Tatsuro Nakaji, Tsutom Hiura
    GEOCHEMICAL JOURNAL 46 (2) 163 - 167 0016-7002 2012 [Refereed][Not invited]
    Isoprene is a reactive volatile organic compound (VOC), the annual global biogenic emissions of which are the largest of the non-methane VOC. Since isoprene emissions are partly temperature-driven, understanding the relationship between isoprene emission and climate must be improved. Isoprene emission was measured in Quercus crispula, the second-most dominant isoprene-emitting tree species in Japan. Four mature Q. crispula trees were exposed to artificial warming of their roots and branches at approximately 5 degrees C warmer than ambient temperatures. Four un-warmed control trees were also measured and compared for their emissions over the course of five months. Basal emission rates of isoprene (defined as a normalized emission rate under standard light and temperature conditions) was calculated and compared between warmed and control branches. The basal emission rates varied from 0.17 to 38.5 nmol m(-2) s(-1) (average; 10.4 nmol m(-2) s(-1)) over the seasons. However, the basal emission rate did not significantly differ between warmed and control leaves.
  • Tatsuro Nakaji, Tsutom Hiura, Hiroyuki Oguma
    Journal of Agricultural Meteorology 67 (2) 65 - 74 1881-0136 2011/09/01 [Refereed][Not invited]
    Numerous studies have used the satellite-derived Normalized Difference Vegetation Index (NDVI) to estimate the phenology of vegetation cover. However, little is known about the effect of species difference on the susceptibility of NDVI-based estimation approaches, such as the threshold approach and the abrupt variation approach, for estimating the phenology of forest trees. In this study, to clarify the utility of NDVI in cool temperate deciduous forests, which consist of many tree species, we investigated the effect of the species difference on the estimation accuracy of two traditional approaches at the scale of the individual tree. We observed a canopy NDVI of 6 tree species by using a high resolution spectral camera, and compared the NDVI-based estimate of the phenological stages (green-up, green peak, senescence and leaf fall) and the ground truth data on the basis of foliar chlorophyll content. In the threshold approach, the optimal threshold value of NDVI was higher in the autumn leaf fall than the spring green-up. Species difference did not strongly affect the threshold of the green-up, but the threshold of the leaf fall was higher in tree species which flower in summer. The mean estimation error of the leafy period was +1.3 days in this approach when the simple threshold value was used for all species. In the abrupt variance approach the estimation error was larger and the leafy period was over estimated (mean: +26.1 days). The degree of overestimation in the leaf fall tended to be larger in species that flower and have a late abscission. These results suggest that the threshold approach is a better method than the abrupt variation approach if the optimal threshold value can be calculated by using a ground truth data set. Furthermore, species specific leaf senescence type and the existence of flowering affect the accuracy of NDVI-based estimates, indicating that we should confirm the composition of tree species when evaluating the NDVI- based phenology data of cool temperate deciduous forests. © 2011, The Society of Agricultural Meteorology of Japan. All rights reserved.
  • Reiko Ide, Hiroyuki Oguma, Tatsuro Nakaji, Takeshi Motohka
    Journal of Agricultural Meteorology 67 (2) 75 - 84 1881-0136 2011/09/01 [Refereed][Not invited]
    Remotely sensed vegetation indices such as the normalized difference vegetation index (NDVI) or enhanced vegetation index (EVI) have been used to scale up flux-based gross primary production (GPP) measurements. Recently, the use of visible-band (VIS) indices for estimation of GPP has been proposed, and VIS_indices derived from digital cameras have been used for detecting phenological changes. To confirm the utility of remotely sensed VIS_indices for the evaluation of GPP in a Japanese larch forest, we investigated the relationships between flux-based GPP measurements and indices derived from both moderate resolution imaging spectroradiometer (MODIS) data and tower-mounted digital camera images. We evaluated the suitability of both traditional (NDVI and EVI) and VIS_indices (the green-red vegetation index (GRVI) and green ratio (GR)) at both satellite and near-surface scales for GPP estimation. We also used the MODIS data to evaluate the sensitivity of the indices to the effects of a severe forest disturbance. The results showed that VIS_indices had several advantages over the traditional indices: (1) seasonal variations in VIS_indices were more strongly correlated with GPP variations (2) the vegetation growing season could be easily discriminated from the winter dormant period, because ground surface conditions affect VIS_indices less than they affect traditional indices (3) the seasonal dynamics of vegetation could be determined at a satellite scale from MODIS data, and possibly even at a canopy scale from digital camera images and (4) interannual variations of VIS_indices were likely to be more sensitive to vegetation changes after a disturbance. These results demonstrate the utility of VIS_indices for estimating GPP at satellite scales and possibly at the canopy scale. We suggest that multi-scale visible-band remote sensing could help our understanding of the ecosystem by improving the temporal and spatial resolutions of satellite data. © 2011, The Society of Agricultural Meteorology of Japan. All rights reserved.
  • Masahiro Nakamura, Onno Muller, Shiori Tayanagi, Tatsuro Nakaji, Tsutom Hiura
    AGRICULTURAL AND FOREST METEOROLOGY 150 (7-8) 1026 - 1029 0168-1923 2010/07 [Refereed][Not invited]
    An increasing number of field experiments have been initiated worldwide to study simulated effects of global warming. To experimentally determine how tall, mature trees respond to warming, we developed a new technique that heated canopy-level branches with electric heating cables. Using a canopy crane, we attached electric cables to top canopy branches of tall, mature Quercus crispula Blume (18-20 m in height) trees; shoot temperature was elevated 5 degrees C above ambient. Branch warming extended the length of the growing season of canopy leaves by later leaf fall. Moreover, branch warming increased acorn production. Application of this technique should lead to a better understanding of how tall, mature trees respond to global warming. (C) 2010 Elsevier B.V. All rights reserved.
  • Reiko Ide, Tatsuro Nakaji, Hiroyuki Oguma
    AGRICULTURAL AND FOREST METEOROLOGY 150 (3) 389 - 398 0168-1923 2010/03 [Refereed][Not invited]
    Integration of CO(2) flux observations with remote sensing technique and ecosystem modeling is expected to be useful for estimation of gross primary production (GPP). We focused on the changes in the two main parameters for the canopy-scale light-response curve-P(max) (maximum GPP at light saturation) and phi (initial slope) as indicators to represent canopy photosynthetic capacity. We hypothesized that P(max) and phi could be evaluated by using spectral reflectance related to the changes in the levels of canopy nitrogen and chlorophyll. We analyzed the relationships between P(max) and phi, derived from tower-based CO(2) flux observations, and ground-based spectral vegetation indices (VIs) in a temperate deciduous coniferous forest. The canopy-scale P(max) and phi showed clear seasonal changes accompanying phenological stages. Both the variations in P(max) and phi were strongly correlated with VIs, especially with the ratio vegetation index (RVI) and enhanced vegetation index (EVI), independent of the growth stages. Moreover, day-to-day short-term variations of P(max) and phi were affected by meteorological conditions such as vapor pressure deficit (VPD) and relative solar radiation which was calculated as the ratio of monitored radiation per theoretical maximum radiation. Thus, seasonal changes of P(max) and phi were effectively assessed by RVI or EVI, and their short-term variations were evaluated by the empirical relationships with VPD and relative solar radiation. We propose a new simple method for estimating GPP with good precision; by fitting the light-response function with the evaluated parameters, the estimated GPP reflects 3 types of temporal variation: diurnal, day-to-day, and seasonal. (C) 2010 Elsevier B.V. All rights reserved.
  • 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.
  • Tatsuro Nakaji, Kyotaro Noguchi, Hiroyuki Oguma
    PLANT AND SOIL 310 (1-2) 245 - 261 0032-079X 2008/09 [Refereed][Not invited]
    To establish new techniques for automatic classification of rhizosphere components, we investigated the utility of visible (VIS) and near-infrared (NIR) spectral images of the rhizosphere under two soil moisture conditions (mean volumetric water content: 0.39 and 0.16 cm(3) cm(-3)). Spectral reflectance images of the belowground parts of hybrid poplar cuttings (Populus deltoides x P. euramericana, I45/51) grown in a rhizobox were recorded at 120 spectral bands ranging from 480 to 972 nm. We examined which wavelengths were suitable and the number of spectral bands needed to accurately classify live roots of four age classes, dead roots, leaf mold, and soil. VIS reflectance (< 700 nm) of live roots first increased and then decreased with age, whereas NIR reflectance (>= 700 nm) was stable in mature roots. The reflectance of dead roots was lower than that of mature roots in both the VIS and NIR spectral regions. VIS reflectance did not differ among dead roots, leaf mold, and soil, but the NIR reflectance was clearly lower in soil than in the other materials. The reflectance of leaf mold and soil increased mainly in the NIR spectral region with reducing soil moisture, but this increase did not affect the order of reflectance intensity among the rhizosphere components in general. Although the most suitable spectral bands statistically selected for classifying rhizosphere components differed somewhat between moist and dry conditions, the spectral bands 580-679 nm (VIS) and 848-894 nm (NIR) provided high reliability under both conditions. Classification accuracy was higher when using two to five VIS-NIR images (overall accuracy >= 87.8%) than three VIS images (red, green, and blue; accuracy < 67.1%). The high accuracy with VIS-NIR was mainly due to successful separation of leaf mold and soil. Irrespective of soil moisture condition, the overall accuracy tended to be stable at 92-94% with use of four VIS-NIR images. The spectral bands effective in wet soil conditions could also be used for classification in dry conditions, with overall accuracies > 86.9%. These results suggest that automatic image analysis using VIS-NIR images at four spectral bands, including red and NIR, allows for accurate classification of the growth stage or live/dead status of roots and distinguishes between leaf mold and soil.
  • 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.
  • Shoko Saji, Srinivas Bathula, Akihiro Kubo, Masanori Tamaoki, Machi Kanna, Mitsuko Aono, Nobuyoshi Nakajima, Tatsuro Nakaji, Tomomi Takeda, Munehiko Asayama, Hikaru Saji
    PLANT AND CELL PHYSIOLOGY 49 (1) 2 - 10 0032-0781 2008/01 [Refereed][Not invited]
    To understand better the plant response to ozone, we isolated and characterized an ozone-sensitive (ozs1) mutant strain from a set of T-DNA-tagged Arabidopsis thaliana ecotype Columbia. The mutant plants show enhanced sensitivity to ozone, desiccation and sulfur dioxide, but have normal sensitivity to hydrogen peroxide, low temperature and high light levels. The T-DNA was inserted at a single locus which is linked to ozone sensitivity. Identification of the genomic sequences flanking the T-DNA insertion revealed disruption of a gene encoding a transporter-like protein of the tellurite resistance/C(4)-dicarboxylate transporter family. Plants with either of two different T-DNA insertions in this gene were also sensitive to ozone, and these plants failed to complement ozs1. Transpiration levels, stomatal conductance levels and the size of stomatal apertures were greater in ozs1 mutant plants than in the wild type. The stomatal apertures of ozs1 mutant plants responded to light fluctuations but were always larger than those of the wild-type plants under the same conditions. The stomata of the mutant and wild-type plants responded similarly to stimuli such as light, abscisic acid, high concentrations of carbon dioxide and ozone. These results suggest that OZS1 helps to close stomata, being not involved in the responses to these signals.
  • Tatsuro Nakaji, Reiko Ide, Hiroyuki Oguma, Nobuko Saigusa, Yasumi Fujinuma
    REMOTE SENSING OF ENVIRONMENT 109 (3) 274 - 284 0034-4257 2007/08 [Refereed][Not invited]
    To estimate the gross CO2 flux (F-CO2) of deciduous coniferous forest from canopy spectral reflectance, we introduced spectral vegetation indices (VIs) into a light use efficiency (LUE) model of mature Japanese larch (Larix kaempferi) forest. We measured the eddy covariance CO2 flux and spectral reflectance of larch canopy at half-hourly intervals during one growing season, and investigated the relationships between the parameters of the LUE model (FAPAR, epsilon) and 3 types of VIs (NDVI, PRI, EVI) in both clear sky and cloudy conditions. FAPAR (fraction of absorbed photosynthetically active radiation) had a positive linear relationship with both NDVI (non-nalized difference vegetation index) and EVI (enhanced vegetation index), and the sky condition had little effect on the relationships. The relative RMSE (root mean square error) of the APAR (absorbed photosynthetically active radiation) based on the incoming PAR and estimated FAPAR from a linear function of NDVI was less than 10.5%, irrespective of sky condition. Half-hourly values of epsilon (conversion efficiency of absorbed energy) showed both seasonal variation related to leaf phenology and short-term variation related to light intensity due to varied sun position and sky condition. Both EVI and PRI (photochemical reflectance index) were significantly correlated with epsilon, EVI showed a positive linear relationship with epsilon as a result of their similar seasonal variation. However, since EVI did not detect short-term variation of epsilon, their relationship differed among sky conditions. On the other hand, although PRI could trace the shortterm variation of epsilon in green needles, the relationship became non-linear due to drastic reduction of PRI in the senescent needles. EVI/(PRI/PRImin), a combined index based on a 6-day moving minimum value of PRI (PRImin), showed a linear relationship with half-hourly values of epsilon throughout the seasons irrespective of sky condition. This index allow us to estimate epsilon in all sky conditions with a smaller error (rRMSE = 35.2%) than using EVI or PRI alone (38.7%-48.7%). Consequently, this combined index-derived epsilon and NDVI-based FAPAR gave a low estimation error of F-CO2, (rRMSE = 36.4%, RMSE = 8.3 mu mol m(-2) s(-1)). Although there are still various issues to resolve, including adaptive limit and combination of vegetation index type, we conclude that the combination of PRI and EVI increased the accuracy of estimation Of CO2 uptake in deciduous forest even though sky conditions varied. (C) 2007 Elsevier Inc. All rights reserved.
  • T Nakaji, H Oguma, Y Fujinuma
    INTERNATIONAL JOURNAL OF REMOTE SENSING 27 (3) 493 - 509 0143-1161 2006/02 [Refereed][Not invited]
    We investigated seasonal changes in the photochemical reflectance index (PRI) and its relation to the diurnal profile of photosynthetic light use efficiency (LUE) in mature Japanese larch ( Larix kaempferi Sarg.) forest throughout the growing season from June to October 2003. The daily mean value of needle PRI showed seasonal variation, strongly correlated with the chlorophyll concentration and carotenoid/ chlorophyll ratio of the needles. During the green period from early June to late September, the hourly values of both PRI and LUE showed significant midday depression, and were positively correlated. In late October, however, because the PRI of yellowing needles tended to increase slightly at midday in contrast to the LUE, this correlation became negative. Even before autumn senescence, the sensitivity of PRI to LUE changed with the season. Correlation analysis indicated that the slope and intercept of the regression line of the PRI-LUE relationship increased during summer, with peaks in July and August, respectively. The seasonal change in slope was strongly correlated with the foliar photosynthetic pigment concentration, nitrogen concentration, air temperature and the daily mean value of the normalized difference vegetation index (NDVI). The value of the intercept was positively correlated with the daily mean PRI. These results suggest that although diurnal change in LUE cannot be estimated quantitatively from PRI on its own throughout the growing season, the combined use of PRI and other variables such as foliar pigments or NDVI could improve the remote evaluation of seasonal changes in LUE of deciduous tree leaves.
  • リモートセンシングによるカラマツ針葉の光利用効率の推定-衛星観測時刻と天候の影響-.
    中路達郎, 小熊宏之, 藤沼康実
    日本森林学会北海道支部論文集(査読付き要旨) 54 87 - 90 2006 [Refereed][Not invited]
  • Effects of ozone and soil water stress, singly and in combination, on leaf antioxidative systems of Fagus crenata seedlings.
    Watanabe, M, Yonekura, T, Honda, Y, Yoshidome, M, Nakaji, T, Izuta, T
    Journal of Agricultural Meteorology 60 1105 - 1108 2005 [Refereed][Not invited]
  • T. Nakaji, T. Takeda, Y. Fujinuma, H. Oguma
    PHYTON-ANNALES REI BOTANICAE 45 (4) 535 - 542 0079-2047 2005 [Refereed][Not invited]
    The influence of autumn senescence on the relationship between the remote-sensored photochemical reflectance index (PRI) and photosynthetic light use efficiency (LUE) was investigated in the needle leaves of young Japanese larch (Larix kaempferi Sarg.) trees. Daily courses of foliar reflectance, xanthophyll cycle activity and gas exchange rates were periodically measured at the 4-year-old larch plantation in Tsukuba, Japan (36 degrees 02'N 140 degrees 04'E) on 30 July, 25 September, 29 October and 19 November 2002. In the larch canopy, visible foliar senescence was observed as yellow coloring of needle blades in November accompanied with reduced needle chlorophyll concentration. The LUE and daily mean PRI were also reduced by autumn senescence. During all observation period except November, daily course of PRI showed midday depression together with epoxidation of xanthophyll pigments, and the PRI was positively correlated to epoxidation state in the xanthophyll cycle (EPS) and the LUE of larch needles. While, in November, although EPS and LUE reduced with the increase of irradiation during daytime, PRI of yellow coloring needle leaves conversely increased at midday. Consequently, negative relationships were found between the midday PRI and LUE on aged leaves in November. The sensitivity of PRI to the LUE was also affected by aging of the needles, and the slope (a) and x-axis intercept (-b/a) in the linear regression line (LUE = a PRI + b) were reduced from September to November. The correlation test for the relationships between the coefficients (a, -b/a) and other ground information (needle pigments, meteorological factors and remote vegetation index) indicated that the coefficients a and -b/a significantly correlated with the foliar chlorophyll concentration and daily mean PRI, respectively. We conclude that the combinational observations of PRI and foliar photosynthetic pigments would increase the accuracy of remote estimation of daily LUE in larch trees through the growing season.
  • T. Nakaji, T. Yonekura, M. Kuroha, S. Takenaga, T. Izuta
    PHYTON-ANNALES REI BOTANICAE 45 (4) 457 - 464 0079-2047 2005 [Refereed][Not invited]
    NAKAJI T., YONEKURA T., KUROHA M., TAKENAGA S. & IZUTA T. 2005. Growth, annual ring structure and nutrient status Of Japanese red pine and Japanese cedar seedlings after three years of excessive N load. - Phyton (Horn, Austria) 45 (4): (457)-(464). An increase in nitrogen (N) deposition from the atmosphere has been one of the major environmental stresses affecting the net primary production and nutritional status of forest ecosystems. In this study, we experimentally investigated the responses of two representative Japanese coniferous tree species, Japanese cedar (Cryptomeria japonica) and Japanese red pine (Pinus densiflora), to rising N load during three growing seasons from April 1999 to March 2002. One-year-old seedlings were planted in potted brown forest soil, and treated with five levels of N supply (0, 25, 50, 100 and 300 mg N 1(-1) fresh soil volume) in April 1999. During the three-year experimental period, N supply to the soil caused soil acidification and leaching of Mn in the soil solution. As for Japanese cedar, the whole-plant dry mass was significantly increased by the higher two N treatments from the end of the second growing season, accompanied with accelerated tree ring growth. The needle Mg concentration of Japanese cedar was also increased by the N treatment. On the other hand, in Japanese red pine seedlings, the two higher N treatments reduced the whole-plant dry mass and needle Mg concentration from the end of the second growing season. The ratio of whole-plant dry mass of N-supplied pine seedlings to the non-treated seedlings negatively correlated with concentration ratios of N/P, N/Mg and Mn/Mg in the needles. No clear relationship was found in the case of Japanese cedar seedlings. We concluded that Japanese red pine has lower tolerance to excessive N input than Japanese cedar, even three years after the experimental N load. The concentration ratios of N/P, N/Mg and Mg/Mn in the needle leaves have potential for use as indicators for evaluating the negative effects of rising N load on the growth of sensitive Japanese coniferous tree species such as Japanese red pine.
  • Influence of elevated air temperature on the relationship between photochemical reflectance index (PRI) and photosynthetic light use efficiency of poplar leaves.
    Nakaji, T, Oguma, H, Fujinuma, Y
    Journal of Agricultural Meteorology 60 989 - 992 2005 [Refereed][Not invited]
  • Responses of Japanese Tree Species to Excessive Nitrogen Load.
    Nakaji, T, Izuta, T
    Proceedings of the International Symposium of the Kanazawa University 21st-Century COE Program 113 - 120 2004 [Not refereed][Not invited]
  • Growth, net photosynthesis and leaf nutrient status of Fagus crenata seedlings grown in brown forest soil acidified with H2SO4 or HNO3 solution.
    Izuta, T, Yamaoka, T, Nakaji, T, Yonekura, T, Yokoyama, M, Funada, R, Koike, T, Totsuka, T
    Trees 18 677 - 685 2004 [Refereed][Not invited]
  • Tatsuro Nakaji, Takuya Kobayashi, Mihoko Kuroha, Kumiko Omori, Yuko Matsumoto, Tetsushi Yonekura, Katsuhiko Watanabe, Jarkko Utriainen, Takeshi Izuta
    Water, Air, and Soil Pollution: Focus 4 (2-3) 277 - 287 1567-7230 2004 [Refereed][Not invited]
    To evaluate the effect of increasing nitrogen (N) deposition and tropospheric ozone (O3) concentrations on N-saturated forest ecosystems, we investigated the response of Japanese red pine (Pinus densiflora), an N-saturation sensitive tree species, to increasing N load under elevated O3 concentrations. One-year-old seedlings of red pine were treated with three levels of N supply (0, 50 and 100 mg N L-1 fresh soil volume) under two levels of atmospheric O3 concentration (< 5 and 60 ppb) for two growing seasons. Nitrogen treatment did not stimulate dry matter production of the seedlings. Growth inhibition was observed in the highest N treatment under low O3 and in the two higher N treatments under elevated O3. Irrespective of the O3 concentration, increasing N supply negatively affected root growth and mycorrhizal development in fine roots, resulting in a reduction in P and Mg uptake from the soil. Net photosynthetic rate was significantly reduced by both the highest N treatment under low O3 and the two higher N treatments under elevated O3, together with decreased N-availability to Rubisco. Nitrogen assimilated from NO3 - to amino acid in the needles was not affected by the treatments. However, needle protein concentration was reduced by the highest N-treatment under low O3 and by the two higher N-treatments under elevated O3. These results suggest that elevated O3 potentially disturbs the N-availability in the form of protein including Rubisco, and may advance the negative effects of excessive N-deposition on N-sensitive plant species in N-saturated forests. © 2004 Kluwer Academic Publishers.
  • Effects of high nitrogen load and ozone on forest tree species.
    Izuta, T, Nakaji, T
    Eurasian Journal of Forest Research 6 155 - 170 2003 [Refereed][Not invited]
  • 中路達郎, 武田知己, 向井 譲, 小池孝良, 小熊宏之, 藤沼康実
    日本林学会誌 85 205 - 213 2003 [Refereed][Not invited]
  • Photosynthetic response of Pinus densiflora seedlings to high nitrogen load.
    Nakaji, T, Takenaga, S, Kuroha, M, Izuta, T
    Environmental Sciences 9 269 - 282 2002 [Refereed][Not invited]
  • 田村俊樹, 米倉哲志, 中路達郎, 清水英幸, 馮 延文, 伊豆田 猛
    大気環境学会誌 37 320 - 330 2002 [Refereed][Not invited]
  • T Nakaji, M Fukami, Y Dokiya, T Izuta
    TREES-STRUCTURE AND FUNCTION 15 (8) 453 - 461 0931-1890 2001/12 [Refereed][Not invited]
    To evaluate the sensitivity of Japanese cedar (Cryptomeria japonica D. Don) and Japanese red pine (Pines densiflora Sieb. et Zucc.) to high N deposition, 1-year-old seedlings were grown in brown forest soil treated with N as NH4NO3 at 0, 25, 50, 100 and 300 mg 1(-1) fresh soil volume, equivalent to 0, 28, 57, 113 and 340 kg N ha(-1). Net photosynthetic rate and whole-plant dry mass of C. japonica seedlings were increased by the N treatment, whilst those of P. densiflora seedlings were significantly reduced by the highest N treatment. The reduction in the net photosynthesis of P densiflora seedlings was mainly due to a depression of carboxylation efficiency accompanied by a decrease in concentration and activity of Rubisco in the needles. In P. densiflora seedlings, needle concentrations of P and Mg were decreased, and the: concentrations of N and Mn were increased by the highest N treatment. The reductions in needle protein concentration and Rubisco activity were negatively correlated with the ratios of NIP and Mn/Mg in the needles. These results suggest that nutrient imbalances of these elements may be induced in P. densiflora seedlings grown under high N deposition. We conclude that P. densiflora is more sensitive to high N deposition than C. japonica, and that the relatively high atmospheric N deposition to Japanese forest ecosystems may adversely affect the health of N-sensitive tree species such as P. densiflora.
  • T Izuta, T Yamaoka, T Nakaji, T Yonekura, M Yokoyama, H Matsumura, S Ishida, K Yazaki, R Funada, T Koike
    WATER AIR AND SOIL POLLUTION 130 (1-4) 1007 - 1012 0049-6979 2001/08 [Refereed][Not invited]
    Dry matter production, net photosynthetic rate, leaf nutrient status and trunk anatomical characteristics of Fagus crenata seedlings grown in brown forest soil acidified by adding H2SO4 solution were investigated. The soil acidification leaded to decreased (Ca+Mg+K)/Al molar ratio in the soil solution. Dry mass per plant of the seedlings grown in the soil treated with H+ at 120 mg.L-1 was significantly reduced compared with the control value at 0 mg.L-1. When net photosynthetic rate was reduced in the seedlings grown in the soil treated with H+ at 120 mg.L-1, the carboxylation efficiency and maximum net photosynthetic rate at saturated CO2-concentration were lower than the control values. The addition of H+ to the soil at 120 mg.L-1 induced a reduction in the concentration of Ca in the leaf. By contrast, the concentration of Al in the leaf was increased with increasing the amount of H+ added to the soil. The annual ring formed in the seedlings grown in the soil treated with H+ at 120 mg.L-1 was significantly narrower than that at 0 (control), 10, 30, 60 or 90 mg.L-1. Based on the results obtained in the present study, we conclude that Fagus crenata is relatively sensitive to a reduction in the (Ca+Mg+K)/Al molar ratio of soil solution compared with Picea abies.
  • T Nakaji, T Izuta
    WATER AIR AND SOIL POLLUTION 130 (1-4) 971 - 976 0049-6979 2001/08 [Refereed][Not invited]
    The effects of ozone (O-3) and excess soil nitrogen (N), singly and in combination, on growth, needle gas exchange rates and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) contents of Pinus densiflora seedlings were investigated. One-year-old seedlings were grown in 1.5-L pots filled with brown forest soil with 3 levels of N supply (0, 100 or 300 mg N.L-1 fresh soil volume). The seedlings were exposed to charcoal-filtered air or 60 +/-5 nL.L-1 O-3 (8 hours a day) in naturally-lit phytotrons for 173 days from 22 May to 11 November. The exposure to O-3 or high N supply to the soil caused a significant reduction in the dry weights of the seedlings. Although no significant interactive effects of O-3 and excess soil N were detected on the dry weight growth of the seedlings, the whole-plant dry weight of the O-3-exposed seedlings grown in the soil treated with 300 mg N.L-1 was greatly reduced compared with the control value. Ozone reduced net photosynthetic rate at 350 mu mol.mol(-1) CO2 (A(350)), carboxylation efficiency (CE) of photosynthesis and Rubisco content without a significant change in the gaseous phase diffusive conductance to CO2 (gs) of the needles. The excess soil N reduced the A(350), CE, gs and Rubisco content of the needles. These results suggest that the reduction in the dry weight growth of Pinus densiflora seedlings induced by the exposure to O-3 and/or excess soil N was caused by reduction in the net photosynthetic rate mainly due to the decrease of Rubisco quantity in the chloroplasts.
  • Effects of ozone and/or excess soil nitrogen on growth, needle gas exchange rates and chlorophyll content of Pinus densiflora seedlings.
    Nakaji, T, Izuta, T
    Proceedings of International Symposium on Oxidants/Acidic Species and Forest decline in East Asia (29-30 November, 1999, Nagoya, Japan) 251-254 2000 [Refereed][Not invited]

Books etc

  • 小池, 孝良, 中村, 誠宏, 宮本, 敏澄 (コラム5-7 「リモートセンシングで解析がすすむ森林と植食生昆虫の関係」)
    農山漁村文化協会 2021/04 (ISBN: 9784540122101) 191p
  • 平野, 恭弘, 野口, 享太郎, 大橋, 瑞江 (第4章 はじめに、第1節「大気CO2濃度およびO3濃度上昇に対する樹木根の応答」、おわりに)
    共立出版 2020/12 (ISBN: 9784320058132) xii, 352p
  • 伊豆田, 猛, 青野, 光子, 石田, 厚, 北尾, 光俊, 黄瀬, 佳之, 佐治, 光, 佐瀬, 裕之, 高木, 健太郎(地球環境科学), 玉置, 雅紀, 徳地, 直子, 中路, 達郎, 増冨, 祐司, 松田, 和秀, 松村, 秀幸, 山口, 真弘, 米倉, 哲志, 渡辺, 誠(農学) (5章第2節 リモートセンシングによる大気環境の植物影響評価)
    朝倉書店 2020/10 (ISBN: 9784254420456) vii, 162p, 図版2枚
  • 伊豆田, 猛 (18. Effects of nitrogen load on Asian trees)
    Springer 2017/02 (ISBN: 4431564365) 331
  • Jones, Hamlyn G., Vaughan, R. A. (Robin Antony), 本岡, 毅, 久米, 篤, 大政, 謙次, 斎藤, 琢, 細井, 文樹, 加治佐, 剛, 村上, 拓彦, 太田, 徹志, 小野, 圭介, 清水, 庸, 中路, 達郎 (11 リモートセンシングの総合的な利用)
    森北出版 2013/09 (ISBN: 9784627261013) xxv, 446p, 図版15p
  • 植物と環境ストレス(伊豆田 猛編著、第2章3節・4節担当)
    コロナ社 2006 (ISBN: 4339067377)


Research Grants & Projects

  • 指標生物群を用いた生態系機能の広域評価と情報基盤整備
    Date (from‐to) : 2009 -2011 
    環境省モニタリング1000、JaLTER、JapanFlux、PEN(Phonological Eyes Network)を連携させ、森林生態系における総合監視システムを構築する(環境省 環境研究・技術開発推進費、研究代表者 北海道大学 日浦 勉、中路は研究協力者として参画)。
  • ガス交換的視点による東南アジア熱帯雨林の機能評価
    Date (from‐to) : 2008 -2011 
    マレーシア国パソ森林保護区において系のガス交換速度と同時に、樹冠の分光反射率を連続的に計測し、植物のフェノロジーと温室効果ガスの吸収・放出ポテンシャルの関係を調査する(研究代表者 京都大学 小杉緑子)。
  • 分光反射による森林植生のフェノロジーと生産性のリモートセンシング
  • Remote estimation of phenology and productivity of forest vegetation using spectral reflectance
    National Institute Special Program of SMI Technology Development

Educational Activities

Teaching Experience

  • Inter-Graduate School Classes(General Subject):Natural and Applied Sciences
    開講年度 : 2020
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 生態学、北方生態系、北海道、植物、動物、昆虫、魚類、微生物、森林、山岳、ツンドラ、沿岸、河川、湿原、相互作用、外来種、野生作物、気候変動 ecology, northern ecosystem, Hokkaido, plants, animals, insects, fishes, microbes, forest, mountain, tundra, seacoast, river, wetland, interaction, invasive species, field crop, climate change
  • Fundamental Course in Biodiversity of Northern Ecosystems
    開講年度 : 2020
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 生態学、北方生態系、北海道、植物、動物、昆虫、魚類、微生物、森林、山岳、ツンドラ、沿岸、河川、湿原、相互作用、外来種、野生作物、気候変動 ecology, northern ecosystem, Hokkaido, plants, animals, insects, fishes, microbes, forest, mountain, tundra, seacoast, river, wetland, interaction, invasive species, field crop, climate change
  • Advanced Course in Forest Sphere Science IV (Regional Resources Management)
    開講年度 : 2020
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 地域資源、地域資源管理、森林管理、森林資源の多様な利用、リモートセンシング regional resources, regional resource management, forest management, diverse use of forest resources, remote-censing
  • Forest Influence
    開講年度 : 2020
    課程区分 : 学士課程
    開講学部 : 農学部
    キーワード : 森林、環境保全機能、生物多様性保全、野生生物保全、土地利用、流域保全、森林利用
  • Seminar on Forest Influence
    開講年度 : 2020
    課程区分 : 学士課程
    開講学部 : 農学部
    キーワード : 森林の種類と分布、森林空間、環境保全機能、森林保全、資料作成方法、発表方法、ディスカッション
  • Freshman Seminar
    開講年度 : 2020
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 生態学、観察実験、進化、食う―食われる関係、温暖化、リモートセンシング、樹木、両生類、昆虫、土壌 ※コロナ感染症対策のためグループワークは削除(2020/9/15)

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