基本情報

所属

• 北方生物圏フィールド科学センター　森林圏ステーション　南管理部

職名

• 教授

学位

• 博士（農学）（東京農工大学）

ホームページURL

http://nakaji-hokudai.jimdo.com/

科研費研究者番号

• 40391130

J-Global ID

• 200901002861057969

プロフィール

• 現在、北大苫小牧研究林にてリモートセンシング技術（分光反射計測）を使って樹木の生理生態的な環境応答の検出研究を進めています。また、北海道からマレーシアまで幅広い気候帯の森林でフィールドワークをしながら、樹木の葉の構造や化学成分の非破壊検出法の開発にも取り組んでいます。
  
  他にも、分光計測を応用した根圏の動態や炭素フローの推定など、日々、新しい研究に意欲的に挑戦しています。興味のある方はご連絡を。

研究キーワード

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

研究分野

• ライフサイエンス / 植物分子、生理科学
• ライフサイエンス / 生態学、環境学
• 環境・農学 / 環境政策、環境配慮型社会
• 環境・農学 / 環境影響評価

担当教育組織

•  学士課程　農学部
•  修士課程　環境科学院
•  博士課程　環境科学院

職歴

• 2023年12月 - 現在 大学院環境科学院 教授
• 2023年12月 - 現在 北海道大学 北方生物圏フィールド科学センター 教授

学歴

•         - 2002年   東京農工大学   連合農学研究科

所属学協会

• 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   

研究活動情報

論文

• Belowground spectroscopy — Novel spectral approach for estimation of vertical and species-specific distributions of forest soil characteristics and heterotrophic respiration

  Tatsuro Nakaji, Naoki Makita, Ayumi Katayama, Hiroyuki Oguma

  Agricultural and Forest Meteorology 339 109563 - 109563 2023年08月 [査読有り][通常論文]
  
• Modeling forest above-ground biomass using freely available satellite and multisource datasets

  Ai Hojo, Ram Avtar, Tatsuro Nakaji, Takeo Tadono, Kentaro Takagi

  Ecological Informatics 74 101973 - 101973 2023年05月
• Accuracy Assessment of Photochemical Reflectance Index (PRI) and Chlorophyll Carotenoid Index (CCI) Derived from GCOM-C/SGLI with In Situ Data

  Taiga Sasagawa, Tomoko Kawaguchi Akitsu, Reiko Ide, Kentaro Takagi, Satoru Takanashi, Tatsuro Nakaji, Kenlo Nishida Nasahara

  Remote Sensing 14 21 5352 - 5352 2022年10月26日 

  The photochemical reflectance index (PRI) and the chlorophyll carotenoid index (CCI) are carotenoid-sensitive vegetation indices, which can monitor vegetation’s photosynthetic activities. One unique satellite named “Global Change Observation Mission-Climate (GCOM-C)” is equipped with a sensor, “Second Generation Global Imager (SGLI)”, which has the potential to frequently and simultaneously observe PRI and CCI over a wide swath. However, the observation accuracy of PRI and CCI derived from GCOM-C/SGLI remains unclear in forests. Thus, we demonstrated their accuracy assessment by comparing them with in situ data. We collected in situ spectral irradiance data at four forest sites in Japan for three years. We statistically compared satellite PRI with in situ PRI, and satellite CCI with in situ CCI. From the obtained results, the satellite PRI showed poor agreement (the best: r=0.294 (p<0.05)) and the satellite CCI showed good agreement (the best: r=0.911 (p<0.001)). The greater agreement of satellite CCI is possibly because satellite CCI contained fewer outliers and satellite CCI was more resistant to small noise, compared to satellite PRI. Our results suggest that the satellite CCI is more suitable for practical use than the satellite PRI with the latest version (version 3) of GCOM-C/SGLI’s products.
• Evaluating the soil microbe community‐level physiological profile using EcoPlate and soil properties at 33 forest sites across Japan

  Masahiro Nakamura, Chisato Terada, Kinya Ito, Kazuaki Matsui, Shigeru Niwa, Masae Ishihara, Tanaka Kenta, Tetsuro Yoshikawa, Taku Kadoya, Tsutom Hiura, Hiroyuki Muraoka, Ken Ishida, Naoki Agetsuma, Ryosuke Nakamura, Hitoshi Sakio, Masahiro Takagi, Akira S. Mori, Megumi K. Kimura, Hiroko Kurokawa, Tsutomu Enoki, Tatsuyuki Seino, Atsushi Takashima, Hajime Kobayashi, Kazuho Matsumoto, Koichi Takahashi, Ryunosuke Tateno, Tomohiro Yoshida, Tatsuro Nakaji, Masayuki Maki, Kazutaka Kobayashi, Karibu Fukuzawa, Kazuhiko Hoshizaki, Kazuhide Ohta, Keito Kobayashi, Motohiro Hasegawa, Satoshi N. Suzuki, Michinori Sakimoto, Yoichiro Kitagawa, Akiko Sakai, Hirofumi Kondo, Tomoaki Ichie, Koji Kageyama, Ayaka Hieno, Shogo Kato, Tatsuya Otani, Yasuhiro Utsumi, Tomonori Kume, Kosuke Homma, Koju Kishimoto, Kazuhiko Masaka, Kenta Watanabe, Motomu Toda, Dai Nagamatsu, Yuko Miyazaki, Tamon Yamashita, Naoko Tokuchi

  Ecological Research 37 3 432 - 445 2022年02月
• Anatomical patterns of condensed tannin in fine roots of tree species from a cool-temperate forest

  Izuki Endo, Miwa Kobatake, Natsuko Tanikawa, Tatsuro Nakaji, Mizue Ohashi, Naoki Makita

  Annals of Botany 128 1 59 - 71 2021年07月28日 [査読有り][通常論文]
   

  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). 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). 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. 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 35 6 DOI: 10.1111/1440-1703.12155. - 1028 2020年10月 [査読有り]
  
• Field data for satellite validation and forest structure modeling in a pure and sparse forest of Picea glehnii in northern Hokkaido

  Tomoko K. Akitsu, Tatsuro Nakaji, Toshiya Yoshida, Rei Sakai, Wataru Mamiya, Terigele, Kentaro Takagi, Yoshiaki Honda, Koji Kajiwara, Kenlo N. Nasahara

  Ecological Research 2020年05月25日 [査読有り][通常論文]
  
• Five-year nitrogen addition affects fine root exudation and its correlation with root respiration in a dominant species, Quercus crispula, of a cool temperate forest, Japan.

  Mioko Ataka, Lijuan Sun, Tatsuro Nakaji, Ayumi Katayama, Tsutom Hiura

  Tree physiology 2020年01月24日 [査読有り][通常論文]
   

  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.
• Exploring patterns of fine root morphological, chemical, and anatomical traits of 12 tree species from visible-near-infrared spectral reflectance

  Natsuko Tanikawa, Tatsuro Nakaji, Hikari Yahara, Naoki Makita

  PLANT AND SOIL 445 1-2 469 - 481 2019年12月 [査読有り][通常論文]
   

  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.
• Quantitative assessment of plant-arthropod interactions in forest canopies: A plot-based approach

  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年10月23日 [査読有り][通常論文]
  
• Harmonized data on early stage litter decomposition using tea material across Japan

  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 2019年09月01日 [査読有り][通常論文]
   

  © 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年05月 [査読有り][通常論文]
   

  As temperature dependence in many biological processes is generally a bell-shaped curve, warming may be benefitial at cooler climate but deterimental at warmer climate. Although warming responses are expected to vary between different temperature regimes even in the same species, such variations are poorly understood. We established open-top canopy chambers, in which average daytime leaf temperature was increased by ca. 1.0 degrees C, at the canopy top of Quercus serrata in a deciduous forest in high (HL) and low (LL) latitude sites and studied temperature dependence of photosynthesis in the leaves across seasons. In control leaves, photosynthetic rates were higher in LL than in HL. Reponse to warming was different between HL and LL; an increase in growth temperature increased photosynthetic rates at higher leaf temperatures in HL but decreased in LL. Lower photosynthetic rate in the warming treatment in LL was partly explained by lower leaf mass per area and leaf nitrogen content per unit leaf area. Optimal temperature that maximizes photosynthetic rate (T-opt) linearly increased with increasing growth temperature (GT) in HL, whereas it was saturating against GT in LL, suggesting that T-opt in Q. serrata has an upper limit. The variation in T-opt was explained by the activation energy of the maximum carboxylation rate (E-aV). Our results suggest an upper limit in temperature acclimation of photosynthesis, which may be one of the determinants of southern limitation of the distribution.
• VALIDATING GCOM-C TERRESTRIAL ECOLOGY PRODUCTS: HOW SHOULD IN-SITU OBSERVATION BE PERFORMED AT SATELLITE SCALE?

  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

  2019 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS 2019) 9196 - 9199 2019年 

  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.
• 無人航空機による３次元データを用いた天然生針広混交林における葉の窒素含量の空間分布.

  井上華央, 柴田英昭, 吉田俊也, 中路達郎, 小花和宏之, 加藤顕

  森林立地 61 1 1 - 13 2019年 [査読有り][通常論文]
  
• 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年 [査読有り][通常論文]
  
• Estimation of six leaf traits of East Asian forest tree species by leaf spectroscopy and partial least square regression

  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 2019年 [査読有り][通常論文]
   

  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.
• Assessment of values and trends in coarse spatial resolution NDVI datasets in Southeast Asia landscapes.

  Arjasakusuma, S, Yamaguchi, Y, Nakaji, T, Kosugi, Y, Shamsuddin, S.-A, Lion, M

  European Journal of Remote Sensing 51 863 - 877 2018年07月 [査読有り][通常論文]
  
• Early stage litter decomposition across biomes

  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 2018年07月 [査読有り][通常論文]
   

  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.
• 8 million phenological and sky images from 29 ecosystems from the Arctic to the tropics: the Phenological Eyes Network

  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 2018年06月26日 [査読有り][通常論文]
   

  We report long-term continuous phenological and sky images taken by time-lapse cameras through the Phenological Eyes Network (http://www.pheno-eye.org. 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 34 43 - 47 北海道大学北方生物圏フィールド科学センター森林圏ステーション 2017年 [査読無し][通常論文]
  
• 生態学者のための分光計測

  奥崎穣, 持田浩治, 永井信, 中路達郎, 小熊宏之

  日本生態学会誌 67 1 41 - 56 2017年 [査読有り][通常論文]
   

  © 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.
• Effects of seasonal change and experimental warming on the temperature dependence of photosynthesis in the canopy leaves of Quercus serrata

  Daisuke P. Yamaguchi, Tatsuro Nakaji, Tsutom Hiura, Kouki Hikosaka

  TREE PHYSIOLOGY 36 10 1283 - 1295 2016年10月 [査読有り][通常論文]
   

  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.
• Root Production of Fagus crenata Blume Saplings Grown in Two Soils and Exposed to Elevated CO2 Concentration: an 11-Year Free-Air-CO2 Enrichment (FACE) Experiment in Northern Japan

  Evgenios Agathokleous, Makoto Watanabe, Norikazu Eguchi, Tatsuro Nakaji, Fuyuki Satoh, Takayoshi Koike

  WATER AIR AND SOIL POLLUTION 227 6 187  2016年06月 [査読有り][通常論文]
   

  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.
• Fine root turnover of Japanese white birch (Betula platyphylla var. japonica) grown under elevated CO2 in northern Japan

  Xiaona Wang, Saki Fujita, Tatsuro Nakaji, Makoto Watanabe, Fuyuki Satoh, Takayoshi Koike

  TREES-STRUCTURE AND FUNCTION 30 2 363 - 374 2016年04月 [査読有り][通常論文]
   

  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.
• Impact of elevated CO2 on root traits of a sapling community of three birches and an oak: a free-air-CO2 enrichment (FACE) in northern Japan

  Evgenios Agathokleous, Makoto Watanabe, Tatsuro Nakaji, Xiaona Wang, Fuyuki Satoh, Takayoshi Koike

  TREES-STRUCTURE AND FUNCTION 30 2 353 - 362 2016年04月 [査読有り][通常論文]
   

  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.
• Responses of Soil, Heterotrophic, and Autotrophic Respiration to Experimental Open-Field Soil Warming in a Cool-Temperate Deciduous Forest

  Nam-Jin Noh, Masatoshi Kuribayashi, Taku M. Saitoh, Tatsuro Nakaji, Masahiro Nakamura, Tsutom Hiura, Hiroyuki Muraoka

  ECOSYSTEMS 19 3 504 - 520 2016年04月 [査読有り][通常論文]
   

  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.
• Different initial responses of the canopy herbivory rate in mature oak trees to experimental soil and branch warming in a soil-freezing area

  Masahiro Nakamura, Tatsuro Nakaji, Onno Muller, Tsutom Hiura

  Oikos 124 8 1071 - 1077 2015年08月 [査読有り][通常論文]
  
• JAXA SUPER SITES 500: LARGE-SCALE ECOLOGICAL MONITORING SITES FOR SATELLITE VALIDATION IN JAPAN

  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 2015年 [査読有り][通常論文]
   

  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).
• Interpreting canopy development and physiology using a European phenology camera network at flux sites

  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 2015年 [査読有り][通常論文]
   

  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.
• Biogeochemical nitrogen properties of forest soils in the Japanese archipelago

  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 2015年01月 [査読有り][通常論文]
   

  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).
• Estimation of light-use efficiency through a combinational use of the photochemical reflectance index and vapor pressure deficit in an evergreen tropical rainforest at Pasoh, Peninsular Malaysia

  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 2014年07月 [査読有り][通常論文]
   

  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.
• 森林における葉形質のリモートセンシング

  中路達郎, 小熊宏之, 日浦勉

  日本生態学会誌 64 3 215 - 221 日本生態学会暫定事務局 2014年 [査読有り][通常論文]
   

  近年、対象物からの反射を連続多波長で分光計測するハイパースペクトルリモートセンシングが生態系研究分野で注目されている。特に先進的な熱帯林の研究では、ハイパースペクトルリモートセングで得られた可視-短波長赤外波長の連続分光反射率データと多変量解析手法を駆使し、樹木の生産力や養分動態、樹種判別に関連した多種類の葉形質の非破壊・同時推定が可能になりつつある。葉形質の時空間変動の把握は気候変動の影響予測や生物多様性の評価においても重要であり、今後、地球規模のニーズに応えるためにも、幅広いバイオームでリモートセンシング研究の発展と生態系研究との一層の連携が期待される。
• Soil warming decreases inorganic and dissolved organic nitrogen pools by preventing the soil from freezing in a cool temperate forest

  Miki U. Ueda, Onno Muller, Masahiro Nakamura, Tatsuro Nakaji, Tsutom Hiura

  SOIL BIOLOGY & BIOCHEMISTRY 61 105 - 108 2013年06月 [査読有り][通常論文]
   

  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.
• Seasonal variation of isoprene basal emission in mature Quercus crispula trees under experimental warming of roots and branches

  Sou N. Matsunaga, Onno Muller, Satoru Chatani, Masahiro Nakamura, Tatsuro Nakaji, Tsutom Hiura

  GEOCHEMICAL JOURNAL 46 2 163 - 167 2012年 [査読有り][通常論文]
   

  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.
• Ground-Based Monitoring of the Leaf Phenology of Deciduous Broad-Leaved Trees using High Resolution NDVI Camera Images

  Tatsuro Nakaji, Tsutom Hiura, Hiroyuki Oguma

  Journal of Agricultural Meteorology 67 2 65 - 74 2011年09月01日 [査読有り][通常論文]
   

  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.
• Advantages of Visible-Band Spectral Remote Sensing at Both Satellite and Near-Surface Scales for Monitoring the Seasonal Dynamics of GPP in a Japanese Larch Forest

  Reiko Ide, Hiroyuki Oguma, Tatsuro Nakaji, Takeshi Motohka

  Journal of Agricultural Meteorology 67 2 75 - 84 2011年09月01日 [査読有り][通常論文]
   

  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.
• Experimental branch warming alters tall tree leaf phenology and acorn production

  Masahiro Nakamura, Onno Muller, Shiori Tayanagi, Tatsuro Nakaji, Tsutom Hiura

  AGRICULTURAL AND FOREST METEOROLOGY 150 7-8 1026 - 1029 2010年07月 [査読有り][通常論文]
   

  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.
• Assessment of canopy photosynthetic capacity and estimation of GPP by using spectral vegetation indices and the light-response function in a larch forest

  Reiko Ide, Tatsuro Nakaji, Hiroyuki Oguma

  AGRICULTURAL AND FOREST METEOROLOGY 150 3 389 - 398 2010年03月 [査読有り][通常論文]
   

  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.
• Change in CO2 balance under a series of forestry activities in a cool-temperate mixed forest with dense undergrowth

  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 2009年05月 [査読有り][通常論文]
   

  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.
• Classification of rhizosphere components using visible-near infrared spectral images

  Tatsuro Nakaji, Kyotaro Noguchi, Hiroyuki Oguma

  PLANT AND SOIL 310 1-2 245 - 261 2008年09月 [査読有り][通常論文]
   

  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.
• Utility of spectral vegetation indices for estimation of light conversion efficiency in coniferous forests in Japan

  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 2008年05月 [査読有り][通常論文]
   

  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.
• Disruption of a gene encoding C(4)-dicarboxylate transporter-like protein increases ozone sensitivity through deregulation of the stomatal response in Arabidopsis thaliana

  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 2008年01月 [査読有り][通常論文]
   

  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.
• Utility of spectral vegetation index for estimation of gross CO2 flux under varied sky conditions

  Tatsuro Nakaji, Reiko Ide, Hiroyuki Oguma, Nobuko Saigusa, Yasumi Fujinuma

  REMOTE SENSING OF ENVIRONMENT 109 3 274 - 284 2007年08月 [査読有り][通常論文]
   

  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.
• Seasonal changes in the relationship between photochemical reflectance index and photosynthetic light use efficiency of Japanese larch needles

  T Nakaji, H Oguma, Y Fujinuma

  INTERNATIONAL JOURNAL OF REMOTE SENSING 27 3 493 - 509 2006年02月 [査読有り][通常論文]
   

  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年 [査読有り][通常論文]
  
• 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 6 1105 - 1108 日本農業気象学会 2005年 [査読有り][通常論文]
  
• Effect of autumn senescence on the relationship hetween the PRI and LUE of young Japanese larch trees

  T. Nakaji, T. Takeda, Y. Fujinuma, H. Oguma

  PHYTON-ANNALES REI BOTANICAE 45 4 535 - 542 2005年 [査読有り][通常論文]
   

  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.
• Growth, annual ring structure and nutrient status of Japanese red pine and Japanese cedar seedlings after three years of excessive N load

  T. Nakaji, T. Yonekura, M. Kuroha, S. Takenaga, T. Izuta

  PHYTON-ANNALES REI BOTANICAE 45 4 457 - 464 2005年 [査読有り][通常論文]
   

  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 5 989 - 992 日本農業気象学会 2005年 [査読有り][通常論文]
  
• 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年 [査読有り][通常論文]
  
• Growth and nitrogen availability of red pine seedlings under high nitrogen load and elevated ozone

  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 2004年 [査読有り][通常論文]
   

  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 2 155 - 170 Hokkaido University Forests, EFRC 2003年 [査読有り][通常論文]
   

  Review
• カラマツ針葉の色素濃度および光合成活性と分光反射指標の関係.

  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 3 205 - 213 THE JAPANESE FORESTRY SOCIETY 2003年 [査読有り][通常論文]
   

  4年生ニホンカラマツ (Larix kaempferi Sarg.) 植林地において, 夏季の葉群の分光反射率と, 純光合成速度, クロロフィル蛍光および葉内色素の日変化を同時に観測し, 葉内色素量や光合成活性と分光反射指標(NDVIおよびPRI) の関係を検討した。日変動を示したNDVIとPRIはともに, 葉内のクロロフィル濃度や総カロテノイド濃度と有意な相関関係になかった。NDVIは, 純光合成速度との間には正の相関が認められたが, 弱光条件下では,その関係にばらつきが生じた。PRIはキサントフィルサイクルの酸化還元状態を反映し, 光合成における光利用効率と光化学系II量子収率の日変動との間に正の相関関係にあった。光合成活性との問の相関係数は, NDVIよりもPRIで高い値が得られた。以上の結果より, カラマツの光合成の日変化に注目した場合, リモートセンシングによって得られるPRIは,光合成の光利用効率を評価する指標として有効であることが明らかになった。
• Photosynthetic response of Pinus densiflora seedlings to high nitrogen load.

  Nakaji, T, Takenaga, S, Kuroha, M, Izuta, T

  Environmental Sciences 9 269 - 282 2002年 [査読有り][通常論文]
  
• 前白根山周辺におけるダケカンバの生育状況、葉内成分および生育土壌に関する調査.

  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 5 320 - 330 公益社団法人大気環境学会 2002年 [査読有り][通常論文]
   

  奥日光の前白根山周辺におけるダケカンバ(Betula ermanii)の衰退状況やその原因究明のための基礎的知見を得るために,2000年6月から10月までの5ヵ月間においてダケカンバの生育状況,葉内成分および土壌の化学性を調査した。前白根山の南東斜面に設定した衰退地で生育しているダケカンバは,北西斜面に設定した非衰退地で生育している個体に比べて,個葉面積が小さく,個体当たりの葉量が少なかった。また,衰退地のダケカンバにおいては,非衰退地の個体に比べて,ハバチ・ハムシ類による食害が激しかった。更に,衰退地のダケカンバにおいては,非衰退地に比べて,葉の黄化時期,落葉の開始時期,葉のクロロフィル濃度,全可溶性タンパク質濃度およびRuBPカルボキシラーゼ/オキシゲナーゼ(Rubisco)濃度の低下が早く,葉の老化が促進されていることが示唆された。したがって,衰退地のダケカンバは,非衰退地の個体に比べて,一成長期において葉をつけている期間が短いため,個葉当たりの光合成同化産物量も少ないことが考えられた。これに対して,衰退地で生育しているダケカンバの葉においては,植物必須元素の欠乏やMnおよびAlの過剰蓄積は認められなかった。また,衰退地の土壌において養分欠乏やAlおよびMnの溶出は認められなかったことから,ダケカンバの衰退を土壌や植物体内の養分欠乏や土壌酸性化では説明できなかった。
• Effects of high nitrogen load on growth, photosynthesis and nutrient status of Cryptomeria japonica and Pinus densiflora seedlings

  T Nakaji, M Fukami, Y Dokiya, T Izuta

  TREES-STRUCTURE AND FUNCTION 15 8 453 - 461 2001年12月 [査読有り][通常論文]
   

  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.
• Growth, net photosynthetic rate, nutrient status and secondary xylem anatomical characteristics of Fagus crenata seedlings grown in brown forest soil acidified with H2SO4 solution

  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 2001年08月 [査読有り][通常論文]
   

  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.
• Effects of ozone and/or excess soil nitrogen on growth, needle gas exchange rates and rubisco contents of Pinus densiflora seedlings

  T Nakaji, T Izuta

  WATER AIR AND SOIL POLLUTION 130 1-4 971 - 976 2001年08月 [査読有り][通常論文]
   

  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.

書籍

• 森林保護学の基礎

  小池, 孝良, 中村, 誠宏, 宮本, 敏澄 (範囲: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年04月 (ISBN: 9784540122101) 191p
• 森の根の生態学 = Root ecology of forest trees

  平野, 恭弘, 野口, 享太郎, 大橋, 瑞江 (範囲: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年12月 (ISBN: 9784320058132) xii, 352p
• 大気環境と植物

  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) (範囲: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年10月 (ISBN: 9784254420456) vii, 162p, 図版2枚
• Air Pollution Impacts on Plants in East Asia

  伊豆田, 猛 (範囲:18. Effects of nitrogen load on Asian trees)
  Springer 2017年02月 (ISBN: 4431564365) 331
• 植生のリモートセンシング

  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 (範囲:11 リモートセンシングの総合的な利用)
  森北出版 2013年09月 (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年 (ISBN: 4339067377)

その他活動・業績

• 帯雨林の三次元構造がもたらす葉リターの分解プロセスの多様性

  花谷周亮, 遠藤いず貴, 福澤加里部, 片山歩美, 中路達郎, 牧田直樹, 大橋瑞江 日本生態学会大会講演要旨(Web) 69th 2022年
• 複数の森林型における森林3次元計測システムOWLの精度検証と今後の展望

  笹川大河, 清柳優里, 秋津朋子, 中路達郎, 奈佐原顕郎 日本森林学会大会学術講演集 132nd 2021年
• 分光・蛍光撮影によるカラマツ細根の枯死分解過程の評価

  中路達郎, 小熊宏之, 大橋瑞江, 牧田直樹 日本森林学会大会学術講演集 131st 2020年
• カラマツ細根の生死判定における分光・蛍光画像および形質観測の有効性

  中路達郎, 小熊宏之, 大橋瑞江, 牧田直樹 根の研究 28 (4) 2019年
• 地中分光計測による森林土壌有機物組成と微生物呼吸の垂直分布の予測

  中路 達郎, 牧田 直樹, 片山 歩美, 安宅 未央子, 小熊 宏之 日本森林学会大会発表データベース 130 (0) 706 -706 2019年 [査読無し][通常論文]
   

  森林土壌の微生物呼吸速度を深度別に予測する分光観測法の開発を試みた。まず、北海道苫小牧市内の森林において13樹種の林床土壌を層別に採取した。細根を除いた土壌のCO₂放出速度を計測し、理化学特性（容積重、水分、リグニン、セルロース、全炭素および全窒素の含有量）を分析した後、含水率を変動させながら近赤外～短波長赤外波長の分光反射率を計測した。これらをもとに、分光反射率から土壌理化学性を予測するPLSRモデルと、土壌理化学性から微生物呼吸を予測する重回帰モデルを作成した。土壌理化学性の予測誤差は <10.7％であり、重回帰モデルで選択された３成分（水分、窒素、セルロース）による微生物呼吸速度の予測誤差は2.1％であった。次に、地中の分光反射率を計測するプローブを制作し、林内に設置したトレンチで深度別の分光反射率と地表面CO₂放出速度の同時観測を行った。分光反射率から予測した深度別のCO₂放出速度を積算した結果、同地点で実測した呼吸速度（1.2～5.9μmol/m²/ｓ）に近い値（2.8～6.7μmol/m²/ｓ）が得られた。まだ多くの課題を含んでいるが、野外の土壌成分と微生物活性の時空間変動の評価に分光観測法が有効であることが示された。

• 温帯ヒノキ林における太陽光誘起クロロフィル蛍光の環境依存性

  桑田清史, 野田響, 小杉緑子, 饗庭正寛, 中路達郎, 辻本克斗, 彦坂幸毅 日本植物学会大会研究発表記録 82nd 230 2018年09月01日 [査読無し][通常論文]
  
• スーパーサイトにおける精密地上検証

  秋津朋子, 奈佐原顕郎, TERIGELE, 中路達郎, 吉田俊也, 坂井励, 間宮渉, 小林元, 岡野哲郎, 三枝信子, 井手玲子, 本多嘉明, 梶原康司, 堀雅裕, 小林秀樹 日本リモートセンシング学会学術講演会論文集(CD-ROM) 64th ROMBUNNO.S2 2018年05月17日 [査読無し][通常論文]
  
• カラマツ属2種の幼木の成長に及ぼす奪葉の影響(予報)

  藤田早紀, 中路達郎, 渡邊陽子, 小池孝良 北方森林研究 (66) 35‐36 2018年02月28日 [査読無し][通常論文]
  
• 熱帯雨林における蒸発散の恒常性について

  小杉 緑子, 高梨 聡, 野口 正二, 伊藤 雅之, 中路 達郎, 鎌倉 真依, 東 若菜, シティ アイシャ, マリアンナ リオン 水文・水資源学会研究発表会要旨集 31 (0) 54 -54 2018年 [査読無し][通常論文]
   

  熱帯雨林機能の評価は、世界的にも重要な課題と目されており、数々の数値実験や衛星データを使った広域マッピングなどが世界中でおこなわれているが、水の影響を定量評価するのに、数値モデリングによる解析や、年・月単位降水量・土壌水分等との単なる相関解析だけでは不十分である。現地測定に基づくガス交換の動的変動に関する詳細な情報に基づいて生態系の反応特性を定量化する作業が不可欠であるが、そのような情報はこれまで限られてきた。15年に及ぶ連続した生態系フラックスデータを有し且つ情報を発信している熱帯雨林サイトは世界中でわずか数箇所であるが、本研究ではそのうち1つ、半島マレーシアのパソ森林保護区における長期観測を元に、熱帯雨林における蒸発散の恒常性について報告する。
• 野外分光計測による樹種・深度別の土壌水分・有機物組成の非破壊推定と土壌呼吸活性の評価

  中路達郎, 牧田直樹, 片山歩美, 安宅未央子, 小熊宏之 日本生態学会大会講演要旨(Web) 65th ROMBUNNO.P2‐302 (WEB ONLY) 2018年 [査読無し][通常論文]
  
• 針広混交林集水域における林冠葉の窒素濃度の空間分布パターン

  井上華央, 柴田英昭, 吉田俊也, 中路達郎, 小花和宏之, 小花和宏之, 加藤顕 日本森林学会大会学術講演集 128th 115 2017年03月26日 [査読無し][通常論文]
  
• 大規模窒素施肥が樹木細根の現存量及び生産量に与える影響の解明

  牧田直樹, 中路達郎, 片山歩美, 高木理恵, 日浦勉 日本森林学会大会学術講演集 128th 90 2017年03月26日 [査読無し][通常論文]
   

  窒素（N）は樹木生長の制限要因であり、N 負荷の増加は生態系炭素循環に多大な影響を与えると考えられている。近年、人為活動によって放出されたN酸化物が大気中を通って生態系に過剰に負荷され、系に対する外部からの圧力が増している。本研究では炭素循環の重要な構成要素である細根に着目し、N 負荷に対する細根系の現存量と生産量の応答を解明する事を目的とした。北大苫小牧研究林の落葉広葉樹林（優占種：ミズナラ）において N 施肥区（100 kgN/ha/yr）と対照区を設定し、尿素散布による N 施肥実験を行った。細根現存量は、直径 5 cm・深さ20 cmの土壌コアを採取し、生きた細根（直径<0.5mm、0.5－2mm）を取り出し乾重を測定した。細根生産量は、イングロースコア法による成長量と枯死量の 2 年間の変化から推定した。二階級に区分した細根現存量において、直径＜0.5mmの根現存量と生産量では、N 区のほうが対象区よりも有意に高かった。一方、0.5-2mmの根現存量と生産量は、共に処理間に有意差は確認されなかった。以上より、本研究の施肥量・期間においては、N 施肥に対する微細根にのみ応答が認められ、根系の資源獲得能や炭素分配に影響を与えることが示唆された。
• 森林生態リモートセンシング研究のための大規模森林調査プロットの整備

  中路達郎, 秋津朋子, 吉田俊也, 日浦勉, 中村誠宏, 柴田英昭, 奈佐原顕郎 日本森林学会大会学術講演集 128th 242 2017年03月26日 [査読無し][通常論文]
   

  人工衛星観測で得られる多波長分光画像などのリモートセンシングデータは、森林の構造や機能を広域評価する際に有用な情報源となる。特に森林の地上部バイオマス（AGB）や葉面積指数（LAI）は物質循環などの生態系サービスを理解するうえで欠かせない基盤情報であり、リモートセンシングによるモニタリングが進められている。一般に、人工衛星データは、各種補正や推定アルゴリズムを経て地表面情報に変換されるが、そのアルゴリズムの改良や品質管理には、地上で実測される高品質データをもとにした検証作業が欠かせない。広域観測衛星の空間分解能は数十～数百ｍと大きく、地上検証にはそれを十分カバーする大規模な調査プロットが必要となる。現在、我々は国内の森林を対象に、落葉広葉樹林（苫小牧）、常緑針葉樹林（雨龍）および落葉針葉樹林（富士北麓：国環研）に500m×500mの共通した地上調査プロットを作成し、AGBとLAIの地上観測を行っている。本発表では、発表者らが中心に運用している北海道の2サイトについて、その概要と生態学研究や教育利用から見た展望について報告する（支援：JAXA GCOM-C PI No. 116）。
• 冷温帯林ミズナラ林冠葉における光合成機能とクロロフィル蛍光の季節変化

  辻本克斗, 加藤知道, 中路達郎, 小熊宏之, 村岡裕由 日本地球惑星科学連合大会予稿集(Web) 2017 2017年
• 短波長赤外分光計測による森林土壌有機物組成の樹種間差の検出

  中路達郎, 牧田直樹, 片山歩美, 安宅未央子, 小熊宏之 日本生態学会大会講演要旨(Web) 64th ROMBUNNO.P2‐N‐399 (WEB ONLY) 2017年 [査読無し][通常論文]
  
• 窒素負荷が落葉広葉樹の開花結実に及ぼす影響

  須貝菜穂, 宮崎祐子, LEE Jin, 長田典之, 中路達郎, 日浦勉 日本生態学会大会講演要旨(Web) 64th ROMBUNNO.P1‐N‐378 (WEB ONLY) 2017年 [査読無し][通常論文]
  
• 長期の土壌温暖化実験がミズナラ上の植物と昆虫の相互作用に与える影響

  中村誠宏, 中路達郎, 日浦勉 日本生態学会大会講演要旨(Web) 64th ROMBUNNO.M01‐05 (WEB ONLY) 2017年 [査読無し][通常論文]
  
• 苫小牧研究林における衛星検証サイトの作成

  中路 達郎, 鷹西 俊和 北方森林保全技術 (33) 32 -37 2016年03月
• 窒素施肥により落葉広葉樹林の土壌呼吸および地下部炭素動態はどう変化するのか?

  片山歩美, 牧田直樹, 高木理恵, 李眞, 安宅未央子, 中路達郎, 日浦勉 日本生態学会大会講演要旨(Web) 63th P2‐437 (WEB ONLY) 2016年 [査読無し][通常論文]
  
• 冷温帯林における窒素付加による植生起源二次有機エアロゾル生成への影響

  宮崎雄三, 川上裕美, 竹内友美, 河村公隆, 中路達郎, 日浦勉 日本地球化学会年会講演要旨集 62nd 28 2015年09月16日 [査読無し][通常論文]
  
• 窒素施肥が樹木の繁殖へ与える影響

  宮崎祐子, 金原悠紀, 季真, 長沼典之, 中路達郎, 日浦勉 日本森林学会大会学術講演集 126th 279 2015年03月26日 [査読無し][通常論文]
  
• 樹木細根系の窒素負荷への応答性:呼吸・窒素含有量・形態特性は変化するのか?

  高木理恵, 牧田直樹, 中路達郎, 片山歩美, 小杉緑子, 日浦勉 日本森林学会大会学術講演集 126th 93 -768 2015年03月26日 [査読無し][通常論文]
   

  本研究は、窒素(N)負荷に対する樹木細根系の呼吸応答について、その因果関係と時間変動の解明を目的とし、呼吸活性と対に形態特性(比根長・根組織密度)及びN含有量を調査した。北大苫小牧研究林の落葉広葉樹林(優占種:ミズナラ)においてN施肥区と対照区を設定し、尿素散布によるN施肥実験を開始した。①50kg/ha/4month、②200kg/ha/16monthの条件下で、表層土壌から細根系を採集した。
  各測定項目について、直径<0.5・0.5-2.0mmの平均値を両区で比較した。両条件共に両階級で、呼吸と比根長に有意差は認められなかった。①条件でのみ両階級で、N区の根密度が有意に小さかった。また両区で、全サンプルにおける呼吸と形態特性・N含有量の関係に対し、回帰直線を求めた。両条件共に両区で、呼吸と比根長・N含有量との関係に有意な正の相関、根密度との関係に有意な負の相関が認められた。各関係で両区の回帰直線に対し共分散分析を行うと、呼吸とN含有量の関係には、①条件で切片に有意差が認められた。一方、形態特性との関係には、両条件共に有意差は認められなかった。以上の結果は、細根系のN応答が時期により変化し、N負荷環境に順応していく可能性を示唆している。
• 半島マレーシア低地フタバガキ林の生態系フラックスは一斉開花の影響を受けるか?

  小杉緑子, 高梨聡, 新山馨, 中路達郎, 野口正二, 奥村智憲, 鎌倉真依, 谷誠, MARRYANNA Lion, SITI Aisha 日本森林学会大会学術講演集 126th 2015年
• デジタルカメラの定点撮影画像による日本各地の植生フェノロジーの把握

  井手玲子, 小熊宏之, 中路達郎, 奈佐原顕郎, 市井和仁, 永井信, 石田昭人, 中村和彦, 藤原章雄, 渡辺隆一 日本地球惑星科学連合大会予稿集(Web) 2015 2015年
• 生態系リモセンのためのJAXAスーパーサイト500

  秋津朋子, 奈佐原顕郎, 小林秀樹, 楊偉, 本多嘉明, 梶原康司, 谷川聡, 三枝信子, 林真智, HABURA Pingchun, 高橋善幸, 廣瀬保雄, 井手玲子, 渡會貴之, 柴田英昭, 日浦勉, 吉田俊也, 高木健太郎, 中路達郎, 福澤加里部, 加藤知道, 高木方隆, 小野祐作, 栗原幸雄, 宮崎理紗 日本農業気象学会全国大会講演要旨 2015 109 2015年 [査読無し][通常論文]
  
• コナラ林冠葉における光合成の温度依存性の時空間的変動が物質生産に与える影響

  山口大輔, 中路達郎, 日浦勉, 芳賀弘和, 三島大, 中村こずえ, 松林玄悟, 佐野淳之, 彦坂幸毅 日本生態学会大会講演要旨(Web) 62nd PA2-074 (WEB ONLY) 2015年 [査読無し][通常論文]
  
• 森林林冠木の光をめぐる競争における個体間相互作用の定量化の試み

  彦坂幸毅, 山口大輔, 長嶋寿江, 中路達郎, 日浦勉 日本生態学会大会講演要旨(Web) 62nd PA2-077 (WEB ONLY) 2015年 [査読無し][通常論文]
  
• コナラ林冠葉における光合成の温度応答の緯度間比較とその生化学的要因の解明

  山口大輔, 中路達郎, 日浦勉, 三島大, 中村こずえ, 佐野淳之, 彦坂幸毅 日本植物学会大会研究発表記録 78th 212 2014年09月01日 [査読無し][通常論文]
  
• ハイパースペクトルデータを用いた温帯林の葉形質の推定

  中路達郎, 小熊宏之, 日浦勉 日本リモートセンシング学会学術講演会論文集 56th 45 -46 2014年05月02日 [査読無し][通常論文]
  
• 落葉広葉樹林への大規模窒素施肥が細根系の呼吸速度及びその形態特性に与える影響の解明

  高木理恵, 牧田直樹, 中路達郎, 片山歩美, 小杉緑子, 日浦勉 日本森林学会大会学術講演集(CD-ROM) 125th 70 2014年03月26日 [査読無し][通常論文]
  
• 樹木根圏の可視‐近赤外反射スペクトルと炭素動態の関係

  中路達郎, 小熊宏之, 高木理恵, 牧田直樹, 日浦勉 日本森林学会大会学術講演集(CD-ROM) 125th 69 2014年03月26日 [査読無し][通常論文]
  
• 日本全国の森林樹木の展葉フェノロジーの予測可能性

  長田典之, 中路達郎, 日浦勉 日本生態学会大会講演要旨(Web) 61st PA1-021 (WEB ONLY) 2014年 [査読無し][通常論文]
  
• 連続分光反射率を用いた葉形質の季節変化の評価

  中路達郎, 小熊宏之, 日浦勉 日本生態学会大会講演要旨(Web) 61st WEB ONLY PA1-068 2014年 [査読無し][通常論文]
  
• 季節変化と温暖化処理がコナラ林冠葉の光合成の温度依存性に与える影響のシミュレーション解析

  山口大輔, 中路達郎, 日浦勉, 彦坂幸毅 日本植物学会大会研究発表記録 77th 231 2013年08月20日 [査読無し][通常論文]
  
• ハイパースペクトルデータを用いた樹木葉形質の非破壊推定

  中路達郎, 小熊宏之, 日浦勉 日本森林学会大会学術講演集(CD-ROM) 124th 235 -695 2013年03月25日 [査読無し][通常論文]
   

  葉の反射スペクトルの観測は、様々な葉内成分や構造の推定に有効である。例えば葉内のクロロフィルやリグニン、セルロースの濃度は特定の2～4波長の反射率から推定できる。このため、これまで多くの森林研究では、目的の波長帯に感度を持つセンサーを別途使い分けて形質を推定し、研究に利用してきた。これに対し、広い波長範囲のスペクトルを多バンドで観測するハイパースペクトルリモートセンシングは多数の葉形質を一度に解析できることから、新しい研究ニーズに応える手法として注目されている。例えば、熱帯林では窒素や水分など10形質の同時推定による樹種判別の高精度化が示され（Asner & Martin 2010）、生物多様性研究に対する貢献が期待されている。今回、我々はアジア地域の森林におけるハイパースペクトルリモートセンシングの可能性を探るために、約200樹種を対象にして個葉の反射スペクトルと形質を計測した。0.4～2.5μmの反射率をもとにPLS回帰モデルを試験した結果、窒素やLMAの推定誤差（rRMSE）は11％程度で、他の主要形質も既報と同レベルあるいはそれ以上の精度で推定できることが明らかになった。
• スキャナを用いた海草・アマモの根の動態解析

  福澤 加里部, 仲岡 雅裕, 中路 達郎, 林 奈津美 根の研究 = Root research 22 (1) 47 -47 2013年03月20日
• 野外操作実験による樹木の温暖化への応答:コナラにおけるトランスクリプトーム解析

  宮崎祐子, 門田有希, 中路達郎, 日浦勉 日本生態学会大会講演要旨集 60th 108 2013年03月05日 [査読無し][通常論文]
  
• 異なる緯度におけるコナラ林冠葉の温度‐光合成関係に対する温暖化処理の影響

  山口大輔, 中路達郎, 日浦勉, 三島大, 中村こずえ, 佐野淳之, 彦坂幸毅 日本生態学会大会講演要旨集 60th 260 2013年03月05日 [査読無し][通常論文]
  
• 開放系大気CO_2増加(FACE)施設で育成したシラカンバの細根動態(会員研究発表論文)

  伊藤 寛剛, 中路 達郎, 王 暁娜, 渡辺 誠, 原 悠子, 小池 孝良 北方森林研究 61 (61) 35 -36 2013年02月18日 [査読無し][通常論文]
  
• 苫小牧研究林の一般公開に関する現状と課題

  杉山弘, 石井正, 小宮圭示, 鷹西俊和, 奥山悟, 及川幸雄, 三好等, 汲川正次, 佐藤智明, 松岡雄一, 中路達郎, 日浦勉 北方森林保全技術 (30) 19 -24 2012年11月30日 [査読無し][通常論文]
  
• Growth and development of birch (Betula sp.) roots grown under elevated CO_2 in FACE (A preliminary result)

  ITO Hirotaka, NAKAJI Tatsuro, WANG Xiaona, WATANABE Makoto, KOIKE Takayoshi 根の研究 = Root research 20 (5) 227 -227 2011年12月20日
• FACE(開放系大気CO₂増加)施設で育成中のカバノキ属3種の葉の生物季節

  伊藤寛剛, 渡辺誠, 渡辺誠, 毛巧芝, 中路達郎, 笹賀一郎, 斎藤秀之, 渋谷正人, 小池孝良 日本森林学会大会学術講演集(CD−ROM) 122nd ROMBUNNO.PB2-73 2011年03月25日 [査読無し][通常論文]
  
• 北海道の冷温帯林における地温上昇が細根動態に及ぼす影響

  福澤加里部, 中路達郎, 中村誠宏, 小熊宏之, 日浦勉 日本森林学会大会学術講演集(CD-ROM) 122nd ROMBUNNO.J31 2011年03月25日 [査読無し][通常論文]
  
• 温暖化処理に伴うミズナラ林冠木の被食量の変化とハイパースペクトル画像による葉の防御物質の評価

  日浦勉, 中路達郎, 田柳詩織, 中村誠宏, MULLER Onno, 小熊宏之 日本生態学会大会講演要旨集 58th 456 2011年03月08日 [査読無し][通常論文]
  
• 開放系大気CO2増加（FACE）施設で育成したカンバ類3種のLAIの変化とシュートの動態

  原 悠子, 伊藤 寛剛, 中路 達郎, 渡辺 誠, 高木 健太郎, 佐藤 冬樹, 小池 孝良 日本森林学会大会発表データベース 123 (0) Pb181 -Pb181 2011年 [査読無し][通常論文]
  
• 可視‐近赤外魚眼カメラを用いた落葉広葉樹林のフエノロジー観察

  中路達郎, 小熊宏之, 田柳史織, 日浦勉 日本生態学会大会講演要旨集 57th 295 2010年03月15日 [査読無し][通常論文]
  
• 近赤外デジタルカメラによる植生フエノロジー観察について

  小熊宏之, 中路達郎, 井手玲子, 日浦勉 日本生態学会大会講演要旨集 56th 227 2009年03月17日 [査読無し][通常論文]
  
• 可視‐近赤外デジタルカメラによる樹木フェノロジーの観察

  中路達郎, 日浦勉, 井手玲子, 小熊宏之 農業環境工学関連学会合同大会講演要旨集(CD-ROM) 2009 ROMBUNNO.B2A 2009年 [査読無し][通常論文]
  
• 針葉樹林の光利用効率推定のための分光指標の検索

  中路達郎, 井手玲子, 高木健太郎, 小杉緑子, 大久保晋治郎, 奈佐原顕郎, 三枝信子, 小熊宏之 日本農業気象学会全国大会講演要旨 2008 2008年
• 落葉・常緑針葉樹林の光利用効率推定における植生指標の有効性評価

  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年 [査読無し][通常論文]
  
• 分光植生指標を用いた森林光合成能力の評価とGPPの推定

  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年 [査読無し][通常論文]
  
• 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年 [査読無し][通常論文]
  
• BIOGEOMON 2002

  中路 達郎, 木平 英一 日本林學會誌 85 (1) 29 -30 2003年02月16日
• 1K1000 スギ苗に対するオゾンと土壌窒素の単独および複合影響

  大葛 貴良, 中路 達郎, 大森 久望子, 黒羽 美穂子, 松本 悠子, 伊豆田 猛 大気環境学会年会講演要旨集 (42) 320 -320 2001年
• 1J0945 アカマツ苗とスギ苗のガス交換速度およびRubisco含量に対する土壌窒素過剰の影響

  中路 達郎, 鈴木 雄太, 竹永 周平, 黒羽 美穂子, 土器屋 由紀子, 伊豆田 猛 大気環境学会年会講演要旨集 (41) 270 -270 2000年
• 1J0930 アカマツ苗とスギ苗の成長および栄養状態に対する土壌窒素過剰の影響

  鈴木 雄太, 中路 達郎, 竹永 周平, 黒羽 美穂子, 小林 卓也, 伊豆田 猛 大気環境学会年会講演要旨集 (41) 269 -269 2000年
• 1D0930 アカマツ苗の生育に対するオゾンと土壌窒素の単独および複合影響

  中路 達郎, 伊豆田 猛 大気環境学会年会講演要旨集 (39) 235 -235 1998年

共同研究・競争的資金等の研究課題

• 熱帯林における太陽光誘起クロロフィル蛍光による光合成量の観測とモデル化

  日本学術振興会：科学研究費助成事業

  研究期間 : 2022年04月 -2026年03月 

  代表者 : 加藤 知道, 宮内 達也, 彦坂 幸毅, 小林 秀樹, 中路 達郎, 野田 響, 冨松 元, 小杉 緑子
• 東ユーラシア低～高緯度域を縦断した大気－森林生態系の物質交換機能解明

  日本学術振興会：科学研究費助成事業

  研究期間 : 2021年09月 -2026年03月 

  代表者 : 熊谷 朝臣, 村岡 裕由, 福田 健二, 久米 朋宣, 清水 貴範, 中路 達郎, 斎藤 琢, 植山 雅仁, 小林 真, 日浦 勉, 飯田 真一, 市榮 智明, 宮沢 良行, 中村 誠宏
• 埋没による土壌深層への長期炭素貯留・隔離：その要因と放出耐性

  日本学術振興会：科学研究費助成事業

  研究期間 : 2022年04月 -2025年03月 

  代表者 : 保原 達, 松本 真悟, 森泉 美穂子, 澤本 卓治, 中路 達郎
• 可視-近赤外分光技術を用いた樹木細根の樹種判別の新たな方法の提案

  日本学術振興会：科学研究費助成事業

  研究期間 : 2021年07月 -2024年03月 

  代表者 : 牧田 直樹, 中路 達郎

   

  複数の樹種が交わる森林生態系において地下部の種の多様性と機能を理解するためには、根の種を同定することが必須である。しかし、詳細な形態情報をもとに種の分類と検索法が確立されている地上部（葉や樹皮）と異なり、根の種識別に関しては、色や形態構造等の情報が乏しく、いまだに客観的な識別法の確立には至っていない。この結果、様々な種が入り交じっている森林生態系での地下部の研究では、その識別の困難さゆえに、根の種を同定せず「根」という区分でひとくくりに扱っているのが現状であり、まさに今、研究のブレークスルーが待ち望まれている。 本課題では、可視-近赤外分光技術を駆使して、根の種識別の課題に挑戦した。分光技術は、対象物からの反射光を連続した多波長に分光し画像として計測する非破壊観測法である。植物組織の分光反射の波長依存性と強度（反射スペクトル）は、色素や有機物、水分などの内部の化学組成や細胞構造の発達段階を反映する。このため、反射スペクトルはリモートセンシングの分野では地上植生の分類や、窒素、水分などのマッピングに利用されており、観測者の主観を排除した客観的評価や再解析を可能にしている。本研究は、この技術を樹木根の観測に応用し、客観的かつ瞬時に種の識別できる方法の確立を目的とした。 初年度は、根系の可視-近赤外分光反射率の技術の確立を実施した。微小な根系に焦点を調節した高解像度ハイパースペクトル（多波長分光）カメラを用いて380～2500nm の連続多波長の分光反射率画像を撮影し、様々な種における樹木根の分光反射率の特徴を形態・太さごとに抽出することを試みた。結果、根系の分光反射率は、樹種ごとで値が大きく異なる、一方、波長ごとに樹種差を超えた類似したパターンを示した。
• 森林光合成とフェノロジーへの気候変動ストレス影響の生理生態学的解明と将来変動予測

  日本学術振興会：科学研究費助成事業

  研究期間 : 2019年04月 -2023年03月 

  代表者 : 村岡 裕由, 中路 達郎, 野田 響, 永井 信, 村山 昌平

   

  本年も新型コロナ感染症拡大により研究活動等は影響を受けたが，以下の成果を得た。 岐阜・高山の落葉広葉樹林では引き続き林冠木の個葉生理生態学的特性のフェノロジーの調査を温暖化実験区と対象区で行った。春の気温の年変動は展葉期を14―16日変動させ，個葉の光合成生産を14―24％変動させると推定された。長期観測と温暖化実験での傾向には大差は認められず，これらの知見から信頼性の高いフェノロジーモデルの構築が可能となる。昨年より延期された国際研究集会を9月にオンライン開催し，成果を発表した。 高山サイトでCO2フラックス・濃度，気象等の観測を継続した。20年程の長期観測データの解析より，年積算正味炭素収支の年々変動は，夏季の炭素収支に依存しており，夏季の日射量・葉面積指数および生物季節の年々変動と高い相関があることが示された。また，数年スケールの変動には台風来襲等による攪乱が影響を及ぼしていることが示唆された。 極端気候などの気象災害や虫害などに対する樹種耐性についてリモートセンシングによって評価し，前年度に有効性が示唆されたGreen Ratioに基づく観測を北海道の落葉広葉樹林において継続し，多地点の定点カメラ観測を実施した。 落葉広葉樹林林冠の分光反射率の季節変化の決定要因を群落放射伝達モデルと個葉放射伝達モデルにより解析した。LAIと個葉の分光特性の季節変化および群落内の幹枝の構造も考慮することにより，実際の林冠反射率の季節変化を再現できた。衛星により観測される森林の季節変化パターンの解析には，個葉や林冠構造に関する知見が不可欠であることが示された。 詳細な地上観測値に基づいて開発した統計的なモデルにより，開葉日と落葉日を100年スケールで推定し，標高に沿った開葉日と落葉日の傾度の時間変化を評価した。また，推定値の妥当性を新たな地上観測値や高空間分可能を持つ衛星データを用いて検証した。
• 樹木細根のフェノロジー：枯死プロセスの解明とその定量評価

  日本学術振興会：科学研究費助成事業

  研究期間 : 2018年04月 -2022年03月 

  代表者 : 大橋 瑞江, 福澤 加里部, 中路 達郎, 牧田 直樹, 平野 恭弘, 野口 享太郎, 檀浦 正子, 大澤 晃

   

  樹木の細根は、葉のように短いサイクルで発生と枯死を繰り返すとされているが、このライフサイクルにおいて、最も不明瞭な部分が衰退から枯死への過程である。そこで本研究では、細根の動きを土壌中でモニタリングしながら枯死を誘導することで、細根の枯死過程を解明することを目的としている。さらに地上部のフェノロジーや土壌環境を同時に計測することで、細根の枯死を支配する要因を特定し、枯死根の定量評価を試みる。そのために次の4つの問に答えるための実験を実施した。① 枯死に伴う細根の形質の変化は何か？② 細根の枯死はどう定義されるか？③ 細根の枯死はいつ、どのくらい発生するか？④ 細根の枯死を引き起こす要因は何か？である。 問①と②について、カラマツとヒノキの伐採後の経過年数が異なる根について、形態や生理状態の変化を求めた。またフィールドで採取した枯死根について、形態・化学組成・色情報などを取得し、枯死根の特性評価を行った。これらの実験では、根系研究者複数名に枯死根判定をしてもらい、判定者の数と判定の一致率を指標として、枯死根評価のばらつきを定量化した。さらに枯死根のばらつきを生む要因を明らかにするために、根の形態変化、分光反射率の変化、成分の変化などを計測した。 問③と④では、フィールド実験を通して枯死の発生パターンを生態系レベルで評価するために、ヒノキの人工林や広葉樹の二次林などで細根動態の観察を行った。これまでに各試験地には市販のスキャナが差し込めるサイズのアクリルボックスを埋設を行った。そこで本年度は、これらのアクリルボックスにスキャナを差し込み、定期的に土壌画像をスキャンした。また、枯死の制御要因として土壌物理環境、地上部フェノロジーに着目し、試験地にセッティングしたこれらの測定機器を用いて、定期的に計測を行った。
• 熱帯雨林生態系における水循環機構と植生のレジリエンスの相互作用の解明

  日本学術振興会：科学研究費助成事業

  研究期間 : 2018年04月 -2022年03月 

  代表者 : 小杉 緑子, 中路 達郎, 伊藤 雅之, 野口 正二, 高梨 聡

   

  本研究は、熱帯雨林の水循環機構と植生のレジリエンスとの相互作用を解明することを目的とする。東南アジア熱帯雨林（Pasoh森林保護区・半島マレーシア低地フタバガキ林）において、いつ・どこに・どれだけ「利用できる水」が存在するか（＝水循環機構）、水ストレスに対する樹木の生存戦略（＝植物水分生理）、ガス交換機能の安定性の中に隠された樹木の反応が示す安定性を支えるメカニズムと限界（＝生態系フ ラックス）、の３つの視点から現地観測を行い、これらの結果をアマゾン熱帯雨林などの他所のデータとも併せて統合的に解析することで、降水量変動に対して熱帯雨林がどのように反応しその機能を保ちうるか（＝熱帯雨林のレジリエンス）を評価するものである。
  本年度は、課題Aについて、保護区内の河川等に設置した水位計・EC計によって降雨流出応答を連続観測を継続している。課題Bについて、昨年度に引き続き、タワーサイト周辺の突出木から林床木まで様々なサイズの樹木において、各部の樹液流速および直径変化を連続測定する。水ポテンシャル、個葉の蒸散・光合成速度、気孔開閉様式、葉および葉柄での貯水量の日変化パターンを乾湿条件の異なるシーズン毎に測定した。課題Cについて、タワー上生態系フラックス（運動量・顕熱・潜熱・蒸発散・CO2フラックス）、分光反射および樹冠画像、降水量、放射各項、各高度での風速・気温・湿度・光量、CO2濃度、土壌各深度における体積含水率・地温・圧力水頭等について、観測を継続し、高品質な長期連続データの取得を行った。
• 近赤外分光法による森林地下部炭素貯留量の時空間変動の解明

  日本学術振興会：科学研究費助成事業

  研究期間 : 2016年04月 -2019年03月 

  代表者 : 中路 達郎, 小熊 宏之, 牧田 直樹, 片山 歩美

   

  森林土壌中の有機物組成および水分含量を簡便かつ迅速に計測する分光計測手法を開発した。北方冷温帯林において多地点のリター、有機物土壌および鉱物土壌を採取しCO2放出速度、土壌成分と近赤外～短波長赤外波長の連続分光反射率を計測した。回帰分析の結果、土壌水分、窒素、セルロース含有量の3成分によってCO2放出速度が予測可能であること、分光反射率からこれらの成分を誤差6～10.3％で推定できることが明らかになった。野外で分光反射率を計測し実測値と比較した結果、深度や樹種による形質・CO2放出速度の差が推定でき、非破壊かつ迅速な土壌炭素成分とCO2放出の空間変動を解析する手法が確立された。
• 森林生態系の炭素代謝プロセス動態の時空間的変動機構の統合的解明と温暖化影響予測

  日本学術振興会：科学研究費助成事業

  研究期間 : 2014年04月 -2018年03月 

  代表者 : 村岡 裕由, 村山 昌平, 中路 達郎, 斎藤 琢, 野田 響, 永井 信, 魯 南賑, 栗林 正俊, 伊藤 昭彦, 加藤 知道

   

  森林生態系の炭素循環や炭素固定機能を決める生態系呼吸の動態メカニズムと林冠光合成の関係を，生態系生理学的手法と大気化学的手法，モデル解析によって解明し，森林生態系機能の変動予測研究を進めることを目的とした。冷温帯地域の落葉広葉樹林や常緑針葉樹林では，温暖化が光合成量と生態系呼吸量の季節性や収支に顕著な影響を及ぼすことが，個葉光合成能の現地観測，樹木と土壌の温暖化実験，複数のモデルシミュレーションによって解明された。
• 長期タワー観測に基づいた気候変動に対する熱帯雨林―大気間交換過程の応答評価

  日本学術振興会：科学研究費助成事業

  研究期間 : 2012年04月 -2017年03月 

  代表者 : 小杉 緑子, 新山 馨, 野口 正二, 中路 達郎, 高梨 聡, 岩田 拓記, 米田 健, 谷 誠, 山下 多聞, 鎌倉 真依, 伊藤 雅之, 檀浦 正子, 田中 克典, 松尾 奈緒子

   

  東南アジア熱帯雨林に属する拠点タワー観測サイト（Pasoh）において、乱流変動法によるタワーフラックスおよび微気象の長期観測を行い、最終的には14年分のデータセットとし、幅広い環境変動に対するガス交換の応答特性を定量評価した。また同時に、バイオマス動態の長期調査を行い、22年分のデータセットとした。これに枯死率・分解率に関する情報を加え、タワー観測により得られた情報とのクロスチェック解析を行うことで、バイオマス、ネクロマス、NEEの3者がどのように振動しながら動的平衡を保っているのかを定量評価した。これらの情報を統合し、気候変動が熱帯雨林－大気間の交換過程に与える影響について考察した。
• 森林林冠木の光をめぐる競争における個体間相互作用の定量化の試み

  日本学術振興会：科学研究費助成事業

  研究期間 : 2013年04月 -2016年03月 

  代表者 : 彦坂 幸毅, 日浦 勉, 中路 達郎

   

  森林樹木は個体間の距離が大きく、林冠に達している個体同士の光獲得競争がどれだけ起こっているかはよくわかっていなかった。本研究では、一枚の葉が受ける光が自身の葉群と隣接個体の葉群を通過すると考え、それぞれの割合を森林群落において二つの方法で定量化することを発案した。その結果、隣接個体の葉群を通過する光の割合はおよそ50％前後であるということが明らかとなった。森林群落でも隣接個体との相互作用が小さくないことが明らかとなった。この成果は、森林樹木における光獲得のゲームのモデル化に利用でき、森林のCO2吸収能力の将来予測に利用可能であると期待される。
• 炭素フラックス観測サイトへの窒素散布実験による物質循環と生物多様性変化の解明

  日本学術振興会：科学研究費助成事業

  研究期間 : 2013年04月 -2016年03月 

  代表者 : 日浦 勉, 徳地 直子, 宮崎 祐子, 中路 達郎, 片山 歩美, 牧田 直樹, 中村 誠宏

   

  北海道大学苫小牧研究林の冷温帯落葉広葉樹二次林において、約10ヘクタールの範囲に3年間にわたり窒素施肥を行い対照区と比較することで、窒素負荷に対する森林生態系の地下部炭素動態、窒素・リンの動態、樹木の繁殖量、植食性昆虫による食害度、の初期応答を明らかにした。これまでの多くの報告とは逆に、施肥によって細根は増加し、土壌呼吸も上昇し、若干のリン酸生成がみられた。またいくつかの樹種で繁殖量が増加する傾向にあった。施肥により2年目のミズナラとケヤマハンノキ林冠葉の形質は変化し食害度の変化はなかったが、3年目になると植食性昆虫の多様性指数が低下した。
• 窒素動態を取り入れた陸域生態系ＣＯ２収支の高精度評価手法の開発

  日本学術振興会：科学研究費助成事業

  研究期間 : 2011年04月 -2014年03月 

  代表者 : 三枝 信子, 日浦 勉, 中路 達郎, 佐々井 崇博, 村岡 裕由

   

  温度環境や窒素負荷量の変化に対する日本の森林の応答を明らかにするための野外操作実験と、日本およびアジアにおけるCO2フラックスの多点観測データの解析に基づき、炭素・窒素収支の環境要因依存性に関する生態系間比較を行い、窒素動態を考慮した生態系の機能・構造とCO2収支の高精度把握を行った。一方、衛星データ重視型の陸域生態系モデルを用いて窒素動態を表すプロセスを高度化し、複数の地上観測サイトで測定された葉のC/N比や炭素収支の季節変化を良好に再現した。このモデルに基づき、1kmの空間分解能で日本付近の自然生態系におけるCO2収支を算出し、炭素・窒素収支の時空間変動とその要因を定量評価した。
• 近赤外ミニライゾトロンによる樹木根圏の温暖化応答の検出

  日本学術振興会：科学研究費助成事業

  研究期間 : 2011年 -2013年 

  代表者 : 中路 達郎

   

  森林の土壌中の炭素の多くは、植物根と植物遺体由来の有機物および腐植の形態で存在し、そのモニタリングと温暖化などの気候変動への応答の解明は将来の森林環境を予測する上で非常に重要である。しかし、地中の炭素量や炭素動態に関係する形質情報を非破壊で推定する手法はまだない。本研究では地中を近赤外波長で画像撮影して非破壊で炭素情報を二次元的に計測する新しいシステムを構築した。従来の可視カラー画像の観察手法と異なり、近赤外波長の情報を利用することで、温暖化に伴う林分の根圏の形質変化を非破壊で検出することに成功した。
• 光学新技術による海底の炭素貯留過程の評価:海草の地下部生産と分解の非破壊的測定

  日本学術振興会：科学研究費助成事業

  研究期間 : 2011年 -2012年 

  代表者 : 仲岡 雅裕, 福澤 加里部, 中路 達郎

   

  光学的な生態系測定法をアマモ場に適用することにより、海草類の地下部の生産量・分解量を評価する方法を確立することを目的とする。屋内水槽実験により、細根の生物量は炭素シンクとしての寄与は無視できないことが判明した。また、可視～近赤外波長の分光画像撮影により、加齢は細根における可視波長反射率を低下させ、枯死は反射率を全体的に低下させることが明らかになった。分光反射率から根の齢、炭素、窒素量が12～37%の誤差推定可能であった。
• 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

  研究期間 : 2009年 -2011年 

  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）。
• 大規模操作実験と地理的環境勾配を用いた令温帯林生態系機能の地理分化の解明

  日本学術振興会：科学研究費助成事業

  研究期間 : 2009年 -2011年 

  代表者 : 日浦 勉, 村岡 裕由, 三枝 信子, 陶山 佳久, 彦坂 幸毅, 内海 泰弘, 佐野 淳之, 中路 達郎, 中村 誠宏

   

  主要構成種(ブナ、ミズナラ、コナラ、ダケカンバ)の遺伝的変異に基づいた森林群集の生食連鎖と腐食連鎖応答を、地理的環境勾配に対する生産者の生理的応答とともに明らかにした。また地球温暖化に対する冷温帯森林生態系の応答を明らかにするため、樹木の地下部と地上部を暖める人工的な温暖化現象を複数地域で作り出し、森林生態系の生産性や物質循環、生物多様性、食物網などへの影響を解明した。
• ガス交換的視点による東南アジア熱帯雨林の機能評価

  科学研究費補助金

  研究期間 : 2008年 -2011年 

  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

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