Abstract
To grasp the change of vegetation around forest roads without revegetation technique, we conducted vegetation analysis considering the period after construction and conditions of location. Experimental design was 3-way layout involving 3 factors, in which the period after construction (11 years or 36 years), openness of vegetation above the road (open or closed), and method of sloping (cutting or filling) were considered. Two sites for each combinations, 16 sites in total, were investigated in 2×5m quadrate. Field survey was conducted in Terasawayama Research Forest, Shinshu University, Japan. Number of arboreal species, mainly sybzoochore shrub, was more in 36-year after construction than in 11-year. Number of herbaceous species and total coverage seemed to increase in the plots where vegetation was open above the road, but we found that the vegetation around forest road was generally sparse. Then, we surveyed wild birds by modified belt-transect survey, which openness of vegetation, special structure and movement of birds were added, so that we might examine the viewpoint of wild bird community as a method evaluating the vegetation around forest roads. In addition to Terasawayama, other 5 sites form the banks of large liver to semi-alpine forests were also surveyed to compare different forest environment. Number of wild bird species had significant relations with openness of vegetation, which the optimal openness for birds varied among sites. Birds showing conspicuous movement during observation were limited almost to the common resident species, and the movements were counted more in the sites where bird species did not determined by the existence of trees or existence of herbs.
