The Changes of Secondary Forests deu to the Decline in Farm Forest Type Usage on the Tama Hills

Abstract

This study aims to clear the relationship between the changes of secondary forests and the decline of farm forest type usage on the Tama Hills.
The secondary forests are divided into 7 types by vegetation investigation. One of these types is the evergreen broad leaved forest. One of the rest of types are the deciduous broad leaved forests, divided by the combination of 2 types in crown and 3 types in forest floor structure. Through the analysis of relationships between the destribution of 7 types and slope direction, and angle of inclination, and cutting time, the following changes of secondary forests are founded.
1) A part of conifer planting forests which had been cut after 1965, Quercus serrata and Quercus accutissima forests which were cut after 1975 at north gently slope and at south steep slope have changed into the forests mixed with tree species which is unsuitable for firewood, for example Cornus contraversa. It is caused by the decline of forest management after cutting. 2) The secondary forest floor dominated by tall Pleioblastus chino or by bush has increased, which is caused by the decline of brush cutting. This change brings the coppies to difficulty in continuity.