Investigation of the effect of qualitative and quantitative leaf phenology on water and carbon exchanges of a tropical seasonal forest in Southeast Asia

• Project/Area Number: 23780161
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Forest science
• Research Institution: Kyoto University
• Principal Investigator: YOSHIFUJI Natsuko 京都大学, (連合)農学研究科(研究院), 研究員 (80514223)
• Project Period (FY): 2011 – 2014
• Project Status: Completed (Fiscal Year 2014)
• Budget Amount: ¥4,550,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥1,050,000); Fiscal Year 2014: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000); Fiscal Year 2013: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2012: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2011: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 熱帯季節林 / ガス交換 / 蒸散 / 季節変化 / フェノロジー / 生理的環境応答 / 光合成 / フラックス / 炭素 / 蒸発散 / 東南アジア / タイ / 熱帯林

Outline of Final Research Achievements

We investigated the factors controlling the seasonal variation in water and carbon exchanges between forest canopy and atmosphere at a deciduous tropical seasonal forest having clear rainy and dry seasons in Southeast Asia based on long-term in-situ observations. Soil moisture increase worked as a dominant factor of leaf-out and transpiration onset. Leaf-fall and the clear decline in leaf photosynthetic capacity (quantitative and qualitative leaf phenology, respectively) were not observed in the beginning of dry season, while the stomatal closure due to soil drought (physiological response to environmental condition) induced the beginning of transpiration decline and the increase in net ecosystem exchange. These indicate that soil moisture change caused by the rainfall seasonality plays an important role on seasonal variations in water and carbon exchanges through leaf-out and stomatal control.

Research Products

• [Journal Article] Inter-annual variation in the response of leaf-out onset to soil moisture increase in a teak plantation in northern Thailand (2014)
  • Author(s): Yoshifuji, N., Igarashi, Y., Tanaka, N., Tanaka, K., Sato, T., Tantasirin, C., Suzuki, M.
  • Journal Title: International Journal of Biometeorology Volume: 印刷中 Issue: 9 Pages: 1-5
  • DOI: 10.1007/s00484-013-0784-2
  • Peer Reviewed
• [Journal Article] Seasonality of water and carbon dioxide exchanges at a teak plantation in northern Thailand (2012)
  • Author(s): Igarashi Y, Tanaka N, Tanaka K, Yoshifuji N, Sato T, Tantasirin C, Suzuki M
  • Journal Title: Ecohydrology Volume: (in press) Issue: 1 Pages: 125-133
  • DOI: 10.1002/eco.284
  • Peer Reviewed
• [Presentation] Effect of leaf morphological and photosynthetic characteristics on canopy carbon and water fluxes of a teak plantation in northern Thailand (2012)
  • Author(s): Natsuko YOSHIFUJI
  • Organizer: The 5th EAFES International Congress
  • Place of Presentation: 龍谷大学瀬田キャンパス
• [Presentation] タイ北部落葉性チーク人工林の蒸散・展葉開始日の年々変動 ‐土壌水分増加とのタイムラグ‐
  • Author(s): 吉藤 奈津子
  • Organizer: 第124回日本森林学会大会
  • Place of Presentation: 岩手大学
• [Presentation] Interannual variation in transpiration onset and its predictive indicator for a tropical deciduous forest in northern Thailand based on 8-year sap-flow records （タイ北部の熱帯落葉林における8年間の樹液流計測に基づく蒸散開始時期の年々変動と予測指標の検討）
  • Author(s): 吉藤 奈津子
  • Organizer: 第124回日本森林学会大会
  • Place of Presentation: 岩手大学
  • Invited