وحید حسینی

Soil Compaction surface and litter mass in the forest floor are two most important characteristics that related to fertility of forest sites in long-term. Timber harvesting operations are know to influnce on soil physicsl propertis and remove up litter mass. The aim of the current study was investigation of soil surface compaction and litter mass recovery on low ( LST ), Modrate ( MST ) and High Skid trails ( HSt ) after twenty years logging in the hyrcanian forest. For achieving this purpose a skid trail about 1 km length which abandon twenty years was selected in east of Mazandaran province in North of Iranian forest. Soil samples for measuring bulk density were examined at 0-100 mm soil depth and litter mass ( kg/ha )were collected in the plot 1 m across the skid trail both in skid trail and undisturbed areas with three replication. Soil bulk density and litter mass most dramatically disturbed in ( HST ). Mean soil bulk densities in the LST, MST and HST were 26,30 and 42% respectively, was greater than undisturbed areas. Litter mass in the LSt, MST and HSt were 3.17% greater, 4 and 20.26% repectively , was lower than those undisturbed areas. Twenty years scince logging soil bulk density was persisted and wasnot recovered full complete in comparison with undisturbed areas. Resultscorroborated that amelioration in soil bulk density and litter mass are needed more time greater twenty years. In order to prevent or at least to maintain currntly minimal-compacted forest soils, it is recommended that decreased the area of high skid trails and smaller machines be used to in the cut block during timber harvesting in Hyrcanian forests.Additionally constructed permanent pathways requiers with a width of 5 m < in order to restricting skidding traffic to this pathways.