The effects of roadside on composition of tree communities in forests of West Guilan Province, Iran

Forest roads are one of the main affecting factors on diversity and composition of plant species. This study aimed to investigate the effects of forest road on composition of tree communities of forests in west of Guilan Province, Iran. Therefore, in two age classes (۰-۱۰ and ۱۰-۲۰ years old) of forest roads with five different distances from the road edge, totally, ۲۴۰ sample plots (۱۵۰ square meters) were taken by line transect method. The results showed that the relative importance of Fagus orientalis, Quercus castaneifolia and Acer velutinum trees on roads with lower age (۰-۱۰ years old) was higher than those with higher age (۱۰-۲۰ years old). The results also indicated that on the newly-constructed roads, the presence of pioneer species (Alnus subcordata and A. cappadocicum) became lower than the other species by moving from the roadside into the forest. In this study, the species importance values of A. subcordata, A. cappadocicum, and A. velutinum decreased from roadside to the forest interior. The results also showed that the Simpson’s diversity and evenness indexin old roads were higher than the young ones. The results of ANOVA analysis showed that by increasing distance from the road, the species diversity and richness declined, while species evenness elevated. The results indicated that there are higher dead trees on the roadside (۰-۳۰ and ۳۱-۶۰ m) compared to the inside of forest.

Keywords:

Road age , Diversity , Forest road , SIV