Updated on 2024/03/01

写真b

OKADA Keiichi

Assistant Professor

Title

Assistant Professor

Contact information

Contact information

Homepage

https://kabo-champilz5.wixsite.com/okdk1

External Link

From School 【 display / non-display

  • Tokyo University of Agriculture   Faculty of Regional Environment Science   Graduated

    2001.04 - 2005.03

From Graduate School 【 display / non-display

  • Shinshu University   Master Course   Completed

    2005.04 - 2007.03

Degree 【 display / non-display

  • Ph.D. ( 2011.03 )

Employment Record in Research 【 display / non-display

  • Tokyo University of Agriculture   Faculty of Bio-Industry   Department of Northern Biosphere Agriculture   Assistant Professor

    2020.04

Research Areas 【 display / non-display

  • Life Science / Forest science

Research Interests 【 display / non-display

  • mycorrhizal symbiosis

  • ecosystem ecology

  • matter cycling

  • functional ecology

  • forest ecology

Papers 【 display / non-display

  • Exploration capacity versus specific enzymatic activity of ectomycorrhizas in response to primary productivity and soil phosphorus availability in Bornean tropical rainforests

    Kei-ichi Okada, Daiki Yokoyama, Shin-ichiro Aiba, Kanehiro Kitayama

    Scientific Reports   2024.02

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    Language:English   Publishing type:Research paper (scientific journal)  

    <jats:title>Abstract</jats:title><jats:p>Ectomycorrhizal (ECM) fungi are functionally important in biogeochemical cycles in tropical ecosystems. Extracellular enzymatic activity of ECM on a ground-area basis is the product of two attributes; exploration capacity (ECM surface-area) and specific enzymatic activity. Here, we elucidated which attribute better explained the ECM enzymatic activity in response to different levels of soil phosphorus (P) and Nitrogen (N) availability in five Bornean tropical rainforests. We determined the surface area of ECM root tips as well as the enzymatic activities per ECM surface area for carbon (C), N and P degrading enzymes in each site. We evaluated the relationship of ECM enzyme activities with the resource availabilities of C (Above-ground net primary production; ANPP), N, and P of ECM by a generalized linear mixed model. The ECM enzymatic activities on a ground-area basis were more significantly determined by specific enzymatic activity than by the exploration capacity. Specific enzymatic activities were generally negatively affected by C (ANPP) and soil P availability. ECM fungi enhance the specific enzyme activity rather than the exploration capacity to maintain the capacity of nutrient acquisition. The less dependence of ECM fungi on the exploration capacity in these forests may be related to the limitation of C supply from host trees. We highlighted the adaptive mechanisms of ECM fungi on nutrient acquisition in tropical ecosystems through the response of enzymatic activity to nutrient availability across the elements.</jats:p>

    DOI: 10.1038/s41598-024-53234-6

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  • Long-term Consequences on Soil Fungal Community Structure: Monoculture Planting and Natural Regeneration. International journal

    Minagi Naka, Shota Masumoto, Keita Nishizawa, Shunsuke Matsuoka, Shinichi Tatsumi, Yuta Kobayashi, Kureha F Suzuki, Xinyu Xu, Tomoya Kawakami, Noboru Katayama, Kobayashi Makoto, Kei-Ichi Okada, Masaki Uchida, Kentaro Takagi, Akira S Mori

    Environmental management   2023.12

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    Language:English   Publishing type:Research paper (scientific journal)  

    Understanding the regeneration and succession of belowground communities, particularly in forests, is vital for maintaining ecosystem health. Despite its importance, there is limited knowledge regarding how fungal communities change over time during ecosystem development, especially under different forest restoration strategies. In this study, we focused on two restoration methods used in northern Japan: monoculture planting and natural regeneration. We examined the responses of the fungal community to monoculture plantations (active tree planting) and naturally regenerated (passive regeneration) forests over a 50-year chronosequence, using natural forests as a reference. Based on DNA metabarcoding, we assessed the richness of fungal Operational Taxonomic Units (OTUs) and their dissimilarity. Our findings revealed that soil fungal richness remained stable after natural regeneration but declined in monoculture plantations, from 354 to 247 OTUs. While the compositional dissimilarity of fungal assemblages between monoculture plantations and natural forests remained consistent regardless of the time since tree planting, it significantly decreased after natural regeneration, suggesting recovery to a state close to the reference level. Notably, the composition of key functional fungal groups-saprotrophic and ectomycorrhizal- has increasingly mirrored that of natural forests over time following passive natural regeneration. In summary, our study suggests that monoculture plantations may not be effective for long-term ecosystem function and service recovery because of their limited support for soil fungal diversity. These results underscore the importance of natural regeneration in forest restoration and management strategies.

    DOI: 10.1007/s00267-023-01917-7

    PubMed

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  • Change of regeneration status on nurse stump associated with the stump size at cool temperate forest

    Okada Kei-ichi, Nakahama Kazuki, Nishimura Yoshinori, Tokita Katsuhiro

    The Japanese Forest Society Congress   134 ( 0 )   337   2023.05

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    Language:English   Publisher:THE JAPANESE FORESTRY SOCIETY  

    <p>[in Japanese]</p>

    DOI: 10.11519/jfsc.134.0_337

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  • Effects of natural regeneration and monospecies planting on organic matter decomposition

    Takeuchi Rie, Nishizawa Keita, Kobayashi Yuta, Masumoto Shota, Suzuki Kureha F, Kawakami Tomoya, Kobayashi Makoto, Katayama Noboru, Okada Keiichi, Tatsumi Shinnichi, Matsuoka Shunsuke, Uchida Masaki, Takagi Kentaro, Mori Akira S

    The Japanese Forest Society Congress   134 ( 0 )   647   2023.05

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    Language:English   Publisher:THE JAPANESE FORESTRY SOCIETY  

    <p>[in Japanese]</p>

    DOI: 10.11519/jfsc.134.0_647

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  • Termite sensitivity to temperature affects global wood decay rates Reviewed

    Amy E. Zanne, Habacuc Flores-Moreno, Jeff R. Powell, William K. Cornwell, James W. Dalling, Amy T. Austin, Aimée T. Classen, Paul Eggleton, Kei-ichi Okada, Catherine L. Parr, E. Carol Adair, Stephen Adu-Bredu, Md Azharul Alam, Carolina Alvarez-Garzón, Deborah Apgaua, Roxana Aragón, Marcelo Ardon, Stefan K. Arndt, Louise A. Ashton, Nicholas A. Barber, Jacques Beauchêne, Matty P. Berg, Jason Beringer, Matthias M. Boer, José Antonio Bonet, Katherine Bunney, Tynan J. Burkhardt, Dulcinéia Carvalho, Dennis Castillo-Figueroa, Lucas A. Cernusak, Alexander W. Cheesman, Tainá M. Cirne-Silva, Jamie R. Cleverly, Johannes H. C. Cornelissen, Timothy J. Curran, André M. D’Angioli, Caroline Dallstream, Nico Eisenhauer, Fidele Evouna Ondo, Alex Fajardo, Romina D. Fernandez, Astrid Ferrer, Marco A. L. Fontes, Mark L. Galatowitsch, Grizelle González, Felix Gottschall, Peter R. Grace, Elena Granda, Hannah M. Griffiths, Mariana Guerra Lara, Motohiro Hasegawa, Mariet M. Hefting, Nina Hinko-Najera, Lindsay B. Hutley, Jennifer Jones, Anja Kahl, Mirko Karan, Joost A. Keuskamp, Tim Lardner, Michael Liddell, Craig Macfarlane, Cate Macinnis-Ng, Ravi F. Mariano, M. Soledad Méndez, Wayne S. Meyer, Akira S. Mori, Aloysio S. Moura, Matthew Northwood, Romà Ogaya, Rafael S. Oliveira, Alberto Orgiazzi, Juliana Pardo, Guille Peguero, Josep Penuelas, Luis I. Perez, Juan M. Posada, Cecilia M. Prada, Tomáš Přívětivý, Suzanne M. Prober, Jonathan Prunier, Gabriel W. Quansah, Víctor Resco de Dios, Ronny Richter, Mark P. Robertson, Lucas F. Rocha, Megan A. Rúa, Carolina Sarmiento, Richard P. Silberstein, Mateus C. Silva, Flávia Freire Siqueira, Matthew Glenn Stillwagon, Jacqui Stol, Melanie K. Taylor, François P. Teste, David Y. P. Tng, David Tucker, Manfred Türke, Michael D. Ulyshen, Oscar J. Valverde-Barrantes, Eduardo van den Berg, Richard S. P. van Logtestijn, G. F. (Ciska) Veen, Jason G. Vogel, Timothy J. Wardlaw, Georg Wiehl, Christian Wirth, Michaela J. Woods, Paul-Camilo Zalamea

    Science   377 ( 6613 )   1440 - 1444   2022.09

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    Publishing type:Research paper (scientific journal)   Publisher:American Association for the Advancement of Science (AAAS)  

    Deadwood is a large global carbon store with its store size partially determined by biotic decay. Microbial wood decay rates are known to respond to changing temperature and precipitation. Termites are also important decomposers in the tropics but are less well studied. An understanding of their climate sensitivities is needed to estimate climate change effects on wood carbon pools. Using data from 133 sites spanning six continents, we found that termite wood discovery and consumption were highly sensitive to temperature (with decay increasing &gt;6.8 times per 10°C increase in temperature)—even more so than microbes. Termite decay effects were greatest in tropical seasonal forests, tropical savannas, and subtropical deserts. With tropicalization (i.e., warming shifts to tropical climates), termite wood decay will likely increase as termites access more of Earth’s surface.

    DOI: 10.1126/science.abo3856

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Books and Other Publications 【 display / non-display

  • 森林学の百科事典

    日本森林学会編( Role: Contributor)

    丸善出版  2021.01 

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    Language:Japanese   Book type:Scholarly book

Misc 【 display / non-display

  • Evaluating demographic non-equilibrium of tree population: four-decade study in a late-successional subalpine forest

    Suzuki Kureha, Kitagawa Ryo, Koide Dai, Okada Kei-ichi, Mori Akira S

    The Japanese Forest Society Congress   131   477   2020.05

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    Language:Japanese   Publisher:THE JAPANESE FORESTRY SOCIETY  

    [in Japanese]

    DOI: 10.11519/jfsc.131.0_477

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Scientific Research Funds Acquisition Results 【 display / non-display

  • 土壌への根系到達による倒木更新木の栄養制限緩和と更新の成否

    Grant number:22K05730  2022.04 - 2025.03

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    岡田 慶一

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    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

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Other External Funds 【 display / non-display

  • 根系発達と倒木腐朽度の時系列動態から紐解く倒木更新の成否

    2021.06 - 2022.03

    農生命科学研究所  2021 年度 若手・女性研究者支援プロジェクト 

    岡田慶一

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    Authorship:Principal investigator 

    Grant amount:\1000000 ( Direct Cost: \1000000 )

  • 熱帯林における菌根菌の菌糸体生産と栄養獲得機能の解明

    2014.04 - 2015.03

    民間財団等  藤原ナチュラルヒストリー振興財団 

    岡田慶一

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    Authorship:Principal investigator  Grant type:Competitive

  • 熱帯林における外生菌根菌の菌糸体生産と栄養獲得機能の解明

    2014.04 - 2015.02

    民間財団等  笹川科学研究助成 

    岡田慶一

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    Authorship:Principal investigator  Grant type:Competitive

Presentations 【 display / non-display

  • 冷温帯天然林における伐根サイズに応じた針葉樹実生更新状況の変化

    岡田慶一, 中濱和紀, 西村祥紀, 時田勝広

    第 134 回⽇本森林学会⼤会  2023.03 

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    Language:Japanese   Presentation type:Poster presentation  

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Teaching Experience 【 display / non-display

  • 森林環境科学

    2020.04

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  • 育林学

    2020.04

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  • Exercise in Geographic Information Analysis

    2022.04 Institution:Tokyo University of Agriculture

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  • Practical training in forestry

    2021.04 Institution:Tokyo University of Agriculture

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  • English for Science

    2021.04 Institution:Tokyo University of Agriculture

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Committee Memberships 【 display / non-display

  • Ecological Society of Japan   Copy editor of Ecological Research  

    2015.05 - 2020.03   

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    Committee type:Academic society