Assessment of Variability among Humus Forms and Soil Properties in Relation to Tree Species and Forest Operations in the Kheyrud Forest, Nowshahr

Tree species and litter play a key role in the functioning of forest ecosystems as influential factors affecting soil ecological processes distribution humus forms. This study investigates morphology under different trees on compacted skid trails at time intervals after skidding operations (6, 10, 20 years) Kheyrud forest, Nowshahr. Each trail was identified with three replications pure beech, beech-hornbeam mixed beech stands total 81 profiles dimensions 30 × cm, drilled classified using European Humus Group Proposal (EHGP). According to results, mull most dominant litter, while amphi abundant form humus. Three types mull, moder, were observed litter. Oligomull Eumacroamphi, Eumesoamphi, Hemimoder common forms moder. Also, thickness organic layer (Organic Organic fragmentation, humus) higher all compared other treatments, from younger (6 older (20 years), organic-mineral horizon (Ah) increased We can conclude that main factor control presence operations.