北九州市近郊における里山林の伐採年代と林分構造に関する基礎的研究(平成15年度日本造園学会全国大会 研究発表論文集(21))

There is a necessity to clarify the present ecological situation of the abandoned Satoyama-forest in northern Kyushu that has been loosing the bio-diversity and its qualities as a fine seasonal landscape. We analyzed a time series of aerial photographs and surveyed the forest structure. Interviews were also conducted with elderly local residents. The results are as follows: 1) Broad-leaved evergreen trees such as Castartopsis cuspidata var. sieboldii and Machilus thunbergii dominantly covered every forest canopy, and except for Zanthoxylum ailanthoides, broad-leaved deciduous trees could rarely be seen. 2) The 15-year regenerative stage of the forest has a higher tree stand density of Z.ailanthoides, than the 30-year staged forest. Despite this the 30-year regenerative stage of the forest has a higher canopy of trees and DBH than the 15-year staged forest. 3) The 40-year stage forest showed gaps in the canopy, and more species are accounted for compared with the 15-year stage forest. However, since trees were shade-tolerant species, there is considered to be a necessity for forest management procedures such as thinning and branching.