Development of biological and physical model for improvement of tsunami mitigation function of coastal forest and evaluation of forest management method

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04976
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 25030:Disaster prevention engineering-related
• Research Institution: Hokkaido Research Organization
• Principal Investigator: Torita Hiroyuki 地方独立行政法人北海道立総合研究機構, 森林研究本部, 研究参事 (50414264)
• Co-Investigator(Kenkyū-buntansha): 田中 規夫 埼玉大学, 理工学研究科, 教授 (80323377)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 津波 / 流速 / 海岸林 / 被害 / クロマツ

Outline of Final Research Achievements

In order to increase the resistance of coastal forests to tsunamis and improve fluid force reduction　effects, the influence of forest management on the tsunami resistance and fluid force reduction of Japanese black pine (Pinus thunbergii Parlat.) coastal forests were simulated using a numerical model for each growth stage of the forest. At the tsunami height of 5 m, no forest damage occurred except in the early growth stages. When the tsunami height exceeded 15 m, overturning or trunk-breakage occurred at all growth stages. The results also indicated that trees are prone to trunk breakage for forest management with a high stand density. At lower tsunami heights, the fluid force reduction was higher in forests with a wider forest width and a higher stand density. However, when the tsunami height exceeded 15 m, differences in forest width and stand density had little effect on the fluid force reduction.

Free Research Field

防災工学、森林科学、雪氷学、自然災害科学

Academic Significance and Societal Importance of the Research Achievements

東北地方太平洋沖地震津波による人的被害および経済的被害は甚大であり、津波発生の危険性が認識されるようになった。津波被害を軽減して海岸域を保全するためには、海岸林が防災機能を効果的に発揮することが期待される。本研究では、森林の管理手法と海岸林の津波抵抗性及び津波減衰効果の関係を定量的に評価した。その成果は、海岸林が防潮機能を発揮し、減災効果を発揮するための基礎的知見の一つとなる。