جستجوی مقالات مرتبط با کلیدواژه "متغیرهای کمی و کیفی" در نشریات گروه "جنگلداری"

Alnussubcordata is one of the native and the fast growing trees in Hyrcanian forests which its plantation helps to conserve and protect the forest. In this study, for surveying the quantitative and qualitative characteristics of Alnussubcordata with changing the elevation above sea level, four sites were selected in Pahne Kolla forests, Sari, Iran. The systematic random method was used for tree sampling and finally the quantitative and qualitative characteristics of 338 trees were measured. Such characteristics as diameter at breast height, slenderness index (h/d), basal area, trees volume (m3/ha), stem quality, canopy percentage and regeneration in the study area were recorded. The results indicated that average DBH, volume and basal area of trees at elevation 430 (m a.s.l) and average height of trees and slenderness index (h/d) at elevation 600 (m a.s.l) were the highest among other elevations. The comparison of average DBH and height of trees in the sites demonstrated that sites have significant difference whit each other. Therefore, according to the results, altitude is an effective factor in the quantitative and qualitative characteristics of Alnus subcordata.