بررسي تاثير برخي متغيرهاي محيطي بر روي گونه نمدار در جنگل هاي غرب مازندران

A Study of the Effects of Some Environmental Variables on Large-leaved Lime (Tilia platyphyllos Scop) in Forests of Western Mazandaran

In order to study the effects of some environmental variables on the quantitative and qualitative characteristics of large-leaved lime (Tilia platyphyllos Scop.) in the forests of the western parts of Mazanderan province, 9 experimental sites were selected. Within each site, three elevations were identified. Also in each site three plots, each of one hectare area (100x100m), in total 27 plots were establishd. Observations as well as experimental results indicated that large-leaved lime extends in a wide range of environmental conditions. This species is distributed from low elevations to high ones and in different exposures; especially northern, eastern and northeastern slopes. The results also revealed that large-leaved lime grows in semi-deep to shallow soils with a medium amount of nutrient content. In most sites, soil texture is clay to clay-silt with pH varying between 5.9 and 7.6. Average annual precipitation varies between 1100 and 1311 mm, with average annual mean temperature varying between 8.1 and 15.2°C. Categorization of sites was accomplished through hierarchical cluster analyse and based on the effects of environmental variables on the quantitative and qualitative characteristics. The quantitative and qualitative characteristics play an important role in site classification because of being affected by environmental variables. There is relationship between ecological characteristics (soil, climate, altitude and slope sides) and quantitative characteristics (diameter at breast height, diameter of crown, total height, height of first branch, as well as height of bi-branch) and qualitative characteristics (stem bending, convolution, as well as stem symmetry of crown).