شناسايي رابطه برخي از عوامل فيزيوگرافي و فيزيكي ـ شيميايي خاك با گروه‏هاي بوم شناختي گياهي در جنگل‏هاي راش شمال ايران

Identification of relationship between some physiographic attributes and physico-chemical properties and plant ecological groups in Fagetum Forests, North of Iran

This study was carried out in Beech forests of Asalem in to district No2 forest management plan. The main objective of the study was to survey the ecological species groups in relation to some physiographic attributes and soil physico-chemical properties. A classified sampling method was used for selecting the position of sample plots and these plots were chosen in different geographical directions (aspect), and totally 73 sample plots in sample lines were considered. The plot size was 400 m2 for shrub and arboreal strata and for grassy strata was 100 m2 considering to Minimal area method and modified braun-blandquet table. At the center and angles of sample plot, soil samples were taken from 0-20 cm layer of mineral soil, and then their were mixed and a combined soil sample was produced for each plot. Clustering classification method was used to classify plant cover, Then indicator species ana lysis method was used to optimum number of cluster and to determine the indicator species each group. It led to separate 3 ecological groups and recognition several indicator species in each group. Thecanonical correspondence analysis (CCA) was applied to determine the relation ships between vegetation data and environmental variables. The results showed that the distribution of species in Fagetum forests of the research region are mainly related to factors such as aspect, pH, clay percentage, porosity percentage, phosphorus absorbable and exchangeable cations (calcium, potassium and magnesium). And indicator plants of the third ecological group establish in fertile soil with low acidity and indicator plants of the first group establish in low fertile soil with high acidity and second group plants establish in moderate condition.