The resilience study about the windthrow in satoyama due to super storm typhoons

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05650
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 39070:Landscape science-related
• Research Institution: Chiba University
• Principal Investigator: Kobayashi Tatsuaki 千葉大学, 大学院園芸学研究院, 教授 (40178322)
• Co-Investigator(Kenkyū-buntansha): 高橋 輝昌 千葉大学, 大学院園芸学研究院, 教授 (20291297) ; 加藤 顕 千葉大学, 大学院園芸学研究院, 准教授 (70543437)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 森林風倒害 / 台風 / レジリエンス / マテバシイ / サンブスギ / 照葉樹林再生

Outline of Final Research Achievements

Analyzing aerial photographs of wind damage caused by the Boso Peninsula Typhoon in 2019, the most severe windthrow damage occurred in Lithocarpus edulis in the evergreen broad-leaved forests. We conducted tree census on the wind damage of L. edulis forest. Though the windthrow damage was mainly uprooting on the land with a less effective soil layer than 1 m, it was mainly stem breakage on the land with a more layer than 1 m. We measured the wind load and wood quality in order to study the cause of windthrow. It was found that the wind load of L. edulis was large compared with other evergreen broad-leave trees due to the large leaf area compared to stem diameter. L. edulis was sensitive to large instantaneous wind speeds and was prone to trunk breakage. The result of regeneration test using native tree species in the wind-damage site showed that natural seedlings were established in the treatment plot where only sprouts were removed without removing fallen trees or planting seedlings.

Free Research Field

緑地環境学

Academic Significance and Societal Importance of the Research Achievements

常緑広葉樹の風倒被害に関する総合的研究は国内外ともに従来例がなく、今後さらに気候変動が強化されると考えられる中で重要な適応対策に関して、樹木風倒と植生・林分形状・個体形状・樹種などとの関係について貴重な新知見を提供している。また、風倒地の再生に関して、生物多様性保全に資する方法を提案しており、その面でも社会的意義がある。