Effect of selection system on variability of some soil microbiological parameters in mixed beech stand of Hyrcanian forests

The goal of study is to explore the impact of selection system on the variability of microbiological indices and characterization of their influencing factors in mixed beech stand of northern temperate forest. For this purpose, 18 sample plots were selected in the control and managed compartments of mixed beech (Fagus orientalis- Carpinus betulus). The plot size was 3×3 m within a gap area about 400 square meters. We measured some physical, chemical and biological soil properties in the depth of 10 cm. The soil respiration (average ± standard deviation) in understory (3.30±0.64 µmol.m2.s-1) was significantly greater than canopy gaps (2.50±0.62 µmol.m2.s-1) while soil organic carbon wasnt significantly different. We found that microbial respiration, microbial biomass carbon and microbial quotient were significant higher at increasing soil moisture and temperature in canopy gaps than understory, which reflected disturbance of canopy gap could change soil characteristics. Whereas, selection system as Silvicultural practices has no significant effect on above mentioned characteristics that could indicate similarities of ecosystems function between the two stands.