Impacts of Forest Road on Plant Species Diversity in a Hyrcanian Forest, Iran

Forest roads facilitate various activities such as forest management, tending of forest, timber logging, and fire and pest control, but the fact remains that roads can interrupt the natural function of forest ecosystem. They divert water flow and increase the amount of sediment. They can also alter plant species composition. Furthermore, the network structure of roads divides the land to small patches, which ends in habitat fragmentation. In this study, which was carried out in the Hyrcanian Forest in the north of Iran, effects of a forest road on plant species diversity (including trees, saplings and herbs) was investigated on both cut and fill slopes. At 10 points along the road, toward the fill slope and cut slope, ten 100 meter transects perpendicular to the road were established. Within each transect, ten 10×10 m plots were sampled to record the tree and sapling species and ten 2 × 2 m plots to record the herbal species. Results showed that road segment had no significant effects on plant species diversity. Since the studied road is constructed using environmentally sound techniques and criteria, unnecessary cut and fill operations were avoided. The other factor is the width of the road, which is as narrow as possible, so the habitat fragmentation is not so considerable. The traffic on this road is also limited; therefore soil pollution does not affect plant composition. These items together with the ability of the Hyrcanian ecosystem to repair itself can mitigate negative effects of this road