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

2014 Fiscal Year Final Research Report

• 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
• 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

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.

Free Research Field

森林水文学