Development of a labor-saving silvicultural system based on cutting by the seed-tree method and lateral weeding of the reserved central part

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K07831
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: Iwate University
• Principal Investigator: Kunisaki Takashi 岩手大学, 農学部, 准教授 (00292178)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 筋残し刈り / 天然更新作業体系 / 広葉樹林化 / 林縁効果

Outline of Final Research Achievements

We proposed a labor-saving silvicultural system based on cutting by the seed-tree method and lateral weeding of the reserved central part. In Quercus serrata mature stands, 50-80 trees/ha of tall tree species are left as mother trees. In consideration of securing saplings from interspecific competition, the mother tree of Q. serrata should be limited to ecologically suitable sites. The lateral weeding is conducted annually until 6 years old, and spot weeding is also conducted depending on the target tree species. Vines are cut off from 3 to 6 years old. Rhus javanica trees reaching the stand canopy surface should be cut down at an earlier stage (around 5 years old) without waiting for the end of the lateral weeding of the reserved central part. For the other pioneer tree species, Clerodendrum trichotomum and Aralia elata, only the relatively thick trunk reaching the stand canopy surface should be cut.

Free Research Field

森林科学、森林計画学、造林学

Academic Significance and Societal Importance of the Research Achievements

機械的な刈り払いである筋残し刈りによる林縁効果の発揮で、クリ、エドヒガン、ミズキなどの初期樹高成長の良い高木性樹種の優占を実証できたことは、大きな学術的意義である。また、誤伐防止のための頭脳集約的な活動が不要であり、刈り払い筋が高密歩道の役割を果たし、つる切りや除伐の足場を確保できるため、省力的な天然更新作業として現場普及しやすい。この点で社会的意義は大きい。