مقایسه زادآوری و تنوع زیستی درختان در ترانشه خاک‌برداری و خاک‌ریزی جاده جنگلی با افزایش فاصله از آن (مطالعه موردی: جنگل‌های چمستان و لاویج، نور)

The evaluation of the edge effects of forest roads on ecosystem is very useful to understand changes from forest road. With this regard, in this research the effect of main forest road construction on regeneration and biodiversity of established trees in edge of forest road was investigated at 35 m distance into forest area. An existing 10 years old road segment, with same physiographic properties, volume per hectare and species composition along the road was selected in Chamestan and Lavige Forests in Mazandaran province. Six linear transactions were set on the fill and cut edge (three transects were set on fill and others on cut edges). Trees’ regenerations were recorded on linear transactions, within circular sample plots by 2 m radius at (2.5, 7.5, 15, 25, 35 m) distances from the road edge. The results showed, no significant differences between trees’ regenerations in the cut and fill edges up to 35 m into the forest area at 0.05 level. However, the average trees’ regenerations in the fill edge were more than the cut edge along the forest road. Maximum and minimum trees’ regenerations density, were recorded in 7.5 and 2.5 m distances from the road edge. The result showed that the maximum densities of trees’ regenerations were belonged to Acer spp and Carpinus betulus species in fill edge and Diospyrus lotus species in cut edge. The comparison of the species diversity and species richness indexes indicated that, the maximum values of species diversity indexes (both Shannon-wiener and Simpson (were in 7.5 m distance and richness indexes (Minhinick and Margalef) were in 2.5 and 15 m distances from the road edge. However, no significant differences were found between indexes in the cut edge and fill edge at 35 m distance (P>0.05).