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北海道有林における森林管理方針の転換と新しい森林施業の特徴
神沼, 公三郎
Permalink : http://hdl.handle.net/2115/49958
KEYWORDS : 道有林;森林管理方針の転換;受光伐;森林環境教育;情報公開;Hokkaido prefectural forest;forest management principle change;overhead release felling;forest environment education;information disclosure
Abstract
2002年の「道有林基本計画」は、道有林経営がそれまでの「公益性と収益性の両方を重んじる考え方」から「公益性を全面的に重視する考え方」に方針転換することを宣言した。その転換に基づいて、実際の森林施業では木材生産を目的とする主伐を廃止して、そのかわりに受光伐を導入した。受光伐とは、植栽木、天然更新している稚樹などの成長に必要な森林内の空間や光環境を確保するために、上層木の伐採を行う技術を意味する。本研究は道有林のこうした方針転換に関する森林施業指針の変遷を整理するとともに、その方針転換が実際の森林施業にいかなる影響を与えているか、道有林上川北部管理区についてケーススタディーを行った。ケーススタディーによると、主伐の廃止と受光伐の導入は、天然林の管理については好ましい結果をもたらしている。しかし、人工林の管理については必ずしも好ましい結果ばかりではない。主伐の廃止により人工林管理に柔軟性がなくなり、硬直的になっている。そのため筆者は、人工林管理においては一定の条件つきで主伐を復活させるよう提案する。またケーススタディーによると、道有林は2002年の方針転換に基づいて地元住民に対する森林環境教育を大幅に拡大し、同時に、地元住民に対して道有林の森林施業を積極的に情報公開するようになった。これらの措置は明らかに「開かれた道有林」を目指すもので、今後、道有林経営が一層、発展していくために不可欠の要素である。
The 2002 Basic Plan for Hokkaido Prefectural Forests declared a change in the forest management policy from the conventional concept of placing emphasis on both public interest and profitability to an approach that focuses entirely on public interest. Based on this change, final cutting for timber production in actual forest operations was abolished and replaced by overhead release felling - a technique involving the cutting of upper-story trees to secure the space and light needed in forests for the growth of planted trees and naturally regenerating seedlings. In this study, the transition of forest operation guidelines related to the prefectural forest policy change in Hokkaido were summarized, and a case study was conducted to determine how the new approach influences actual forest operations in the Northern Kamikawa Forest Management District. The case study revealed that the abolition of final cutting in favor of overhead release felling brought positive results in terms of natural forest management. However, the outcomes in the area of artificial forest management were not necessarily favorable, as it lost flexibility and became rigid due to the abolition. Against this background, the author proposes the resumption of final cutting in artificial forest management under certain conditions. The case study also showed that the provision of forest environment education for local residents has expanded significantly based on the 2002 policy change. At the same time, the disclosure of information on prefectural forest operations to local residents has also been promoted. It is clear that the goal of these measures is to open prefectural forests to the public, which is a vital consideration for the further development of prefectural forest management.
The 2002 Basic Plan for Hokkaido Prefectural Forests declared a change in the forest management policy from the conventional concept of placing emphasis on both public interest and profitability to an approach that focuses entirely on public interest. Based on this change, final cutting for timber production in actual forest operations was abolished and replaced by overhead release felling - a technique involving the cutting of upper-story trees to secure the space and light needed in forests for the growth of planted trees and naturally regenerating seedlings. In this study, the transition of forest operation guidelines related to the prefectural forest policy change in Hokkaido were summarized, and a case study was conducted to determine how the new approach influences actual forest operations in the Northern Kamikawa Forest Management District. The case study revealed that the abolition of final cutting in favor of overhead release felling brought positive results in terms of natural forest management. However, the outcomes in the area of artificial forest management were not necessarily favorable, as it lost flexibility and became rigid due to the abolition. Against this background, the author proposes the resumption of final cutting in artificial forest management under certain conditions. The case study also showed that the provision of forest environment education for local residents has expanded significantly based on the 2002 policy change. At the same time, the disclosure of information on prefectural forest operations to local residents has also been promoted. It is clear that the goal of these measures is to open prefectural forests to the public, which is a vital consideration for the further development of prefectural forest management.
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