Does heavy masting enhance survivorship of seedlings in beech forest?

Research Project

Project/Area Number	16K14938
Research Category	Grant-in-Aid for Challenging Exploratory Research
Allocation Type	Multi-year Fund
Research Field	Forest science
Research Institution	Shizuoka University
Principal Investigator	Iio Atsuhiro 静岡大学, 農学部, 准教授 (90422740)
Co-Investigator(Kenkyū-buntansha)	水永博己静岡大学, 農学部, 教授 (20291552) 片畑伸一郎岐阜大学, 応用生物科学部, 助教 (80648395)
Project Period (FY)	2016-04-01 – 2019-03-31
Project Status	Completed (Fiscal Year 2018)
Budget Amount *help	¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000) Fiscal Year 2018: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000) Fiscal Year 2017: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000) Fiscal Year 2016: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Keywords	マスティング / ブナ / 葉面積 / 光環境 / 光合成量 / 葉分布構造 / 葉面積指数 / 林床光環境 / 稚樹の成長 / 樹冠構造 / 実生成長
Outline of Final Research Achievements	Masting impact on stand structure, light environment and photosynthesis was examined in mature beech stands on Mt. Naeba, Japan. Heavy masting decreased stand leaf area to the half of that in non-masting year, due to decrease in individual leaf size. This structural change mainly occurred in sunlit part of the canopy where many fruits are born. We have estimated the masting impact on within-stand light environment and photosynthesis with process-based model. Although the reduction of leaf area decreased stand photosynthesis by 20%, photosynthesis at lower part of the canopy and understory vegetation increased 2-3 times compared to that in in non-masting year. This result implies that masting may contribute to maintain branches in lower part of canopy and understory vegetation.
Academic Significance and Societal Importance of the Research Achievements	マスティング（大量一斉結実）による林分葉面積の低下が、樹冠下層や林床の光環境を改善し、階層構造の発達や林床植生の維持に貢献する可能性を示した。本研究の学術的意義は、これまで繁殖戦略として理解されていたマスティング現象に、3～10年周期で、薄く広く林床に光を供給する、いわばギャップとしての役割があることを示したことにある。