Variability of soil physical, chemical and biological properties in developmental stages of beech (Fagus orientalis Lipsky) forest of Asalem, Gilan Province, Iran

This study aimed at evaluating the physical, chemical and biological properties of soil in the developmental stages of oriental beech (Fagus orientalis Lipsky) forest in Asalem-Guilan region. Three 1-hectare plots (100 ×100 m2) with different stages of development including initial, optimal and decay were selected. Soil sampling was carried out at a depth of 0-20 cm in the four corners of the five sub-plots of 400 m2 each, and the samples (n = 60) were analyzed in the laboratory. The results showed significant difference of soil texture amongst the three developmental stages of beech forest. The developmental stages of beech forest were significantly different in terms of available potassium, organic carbon content, C/N, iron, manganese, copper and zinc. The highest mean respiration rate, microbial biomass carbon and phosphorus, MBC/MBN ratio and MBP/MBN ratio were observed in the decay stage. These results indicated that decay stage is more favorable in terms of microorganism activity. The results also showed that biological and microbial properties are more appropriate indices for revealing differences in developmental stages. The results generally revealed that developmental stages of beech stand with respect to age and structural conditions cause changes in soil physical, chemical and biological characteristics. The results in the control compartment could be used as a basis in other forest stands for silvicultural and rehabilitation measures.