A New Method for Thinning Forest by Reserved Tree Marking System

概要

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Overcrowded forests are frequently seen in various regions of Nagano Prefecture due to the decreased of forest workers. Accordingly, to prevail reasonable forest management such as reduction of labors became an important problem which calls for an urgent answer fitting present social situation on the forestry in Japan. In the present study, the author proposed a new method for thinning by the reserved tree marking system in order to obtain thicker and more excellent trees within the relatively short period. In the initial step, superiority or inferiority in tree growth was estimated in a given forest using the site index curve, in addition reasonable tree density taking into consideration of height of the upper trees in 60-year stand age was estimated, and thereafter suitable trees selected as final cutting trees were marked. The distribution of the reserved trees should be considered when the trees are selected. At the first time of thinning, the trees which are expected to prevent the growth of the reserved trees should be removed regardless of their growth or quality conditions. In addition, short diameter trees which ara not expected to yield in the future should be removed. Other trees remin up to next thinning time. The new method provided conspicuous effectiveness for thinning.
信州大学農学部の論文
1990-01-30