Why structural complexity enhances forest productivity? Eco-physiological mechanisms within canopy

2022 Fiscal Year Final Research Report

• Project/Area Number: 18H02236
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 40010:Forest science-related
• Research Institution: Shizuoka University
• Principal Investigator: Iio Atsuhiro 静岡大学, 農学部, 准教授 (90422740)
• Co-Investigator(Kenkyū-buntansha): 楢本 正明 静岡大学, 農学部, 准教授 (10507635) ; 水永 博己 静岡大学, 農学部, 教授 (20291552)
• Project Period (FY): 2018-04-01 – 2023-03-31
• Keywords: 樹冠構造 / 樹種多様性 / 光合成 / 樹液流 / ドローン / LiDAR

Outline of Final Research Achievements

Species diversity of canopy structure and eco-physiological functions from leaf to tree level were examined for major tree species in Pacific Ocean-type cool temperate forest in Japan. Although species diversity of crown-level leaf area, photosynthesis and transpiration were generally small, there were large inter-species variations in within-crown structure and functions, such as three-dimensional leaf area distribution and light use efficiency. With respect to temporal heterogeneity of structure and functions, we compared vegetation indices derived from drone RGB imagery with ground-observed leaf phenology and stem sap flow. We revealed that crown thickness has significant impact on drone-derived leaf phenology and that UAV image is effective for evaluating species diversity of transpiration phenology. We also revealed that Fagus crenata markedly changes leaf distribution according to soil water conditions, whereas the other species did not show such trend.

Free Research Field

森林生理生態学

Academic Significance and Societal Importance of the Research Achievements

構造と機能の多様性は、常緑樹と落葉樹、陰樹と陽樹など、生活型の大きく異なる種の比較で示されてきたが、本研究は生活型が似ていても種によって葉面積の空間分布や光利用戦略が大きく異なることを明らかにし、種の個性を詳細に調べることの重要性を示した。また、ドローンのRGB画像が樹冠フェノロジーの樹種多様性の評価に有効なツールであることを示した。特に、RGB画像から計算される植生指標と個体蒸散量の季節変化を比較し、ドローン画像が構造だけでなく機能的フェノロジーの評価に有効であることを示した。