Variations in humus and fine root properties related to development stages in a temperate natural Beech forest

Understanding variations in soil humus and fine root properties in Oriental beech (Fagus orientalis L.) stand in response to development stages in temperate Hyrcanian forests is essential for sustainable forest management. The development stages of beech stand (initial, optimal and decay) were determined, and three plots of 100 x 100 m (1 ha) were chosen at each development stage. Five subplots in size 20 x 20 m were randomly selected at plots of 1 ha. The concentrations of humus elements (C, P, K, Mg, Fe and Zn) differed significantly among the development stages in spring and autumn seasons within Beech forest. The comparison of mean chemical compounds of humus layer in spring and autumn seasons using t test showed significant difference for each the development stage. Differences in C, N and P concentrations and also C/N and N/P ratios in fine roots of beech trees were significant among development stages, while C/P ratio was insignificant. The mean values of N and P for initial stage were higher, but C and N/P ratio were higher for optimal stage. The highest C/N value was observed in decay stage. There were statistically significant effects of development stages on fine root biomass and morphology traits at different diameter classes in beech trees. No statistically significant impacts of development stages were observed on fine root morphology of beech trees, except for fine root density. Our results reveal the important role that different development stages may play in Beech forest regarding variations in chemical properties of fine roots and soil humus.