بررسی تاثیر شدت های مختلف تنک کردن بر خصوصیات کمی و کیفی جنگل دست کاشت کاج تدا

The infLuence was studied of thinlling at 18 yr old and 2 x 3 m spacing on the Diameter growth of loblolly pine trees in the coastal plain region of Gilan province The ex ecutive form of project is the Randomized complete block designs with 4 replications and 3 treatments ( 2 intensity of thinning and 1 Control) in 1.2 hectare area During 5 years 3 intensity of thinrling ( 15 and 30 Basal area levels ) were CarrIed out . T~p results are as follows Number of trees per hectare : 1220 stem Age : 18 years old . Average stand Diameter 20.7 crn Average stand height Stand volume : 315.4 14.4 m 3 m /ha Nean annual increament : 17.5 mJ/ha . Light and hear'y thinn:ing increased the diameter growth at 26.3 and 22.5 percentand differences are significant