Investigation on adaptation and growth characteristics of different closed-crown poplar clones under climatical conditions of Khorram Abad

In order to identify the most productive and adaptable clones to local climate and introduce them to people for mass wood production, ten clones of Populus nigra L. were selected and were planted in Khorram Abad Agricultural Garden Station for five years (2010-2014). Variance analysis showed that the year and cologne factors had a significant impact on height, diameter, and volume increment. The result of mean comparisons showed that the highest (2.05 m) and lowest (0.14 m) of height increment were dedicated to P. nigra 63/135 clone in the fourth year and P. nigra 56/48 clone in the second year, respectively. Also the P. nigra 63/135 clone had the maximum diameter increment (2.57 cm) in the fifth year (2014) and P. nigra 56/48 clone had the minimum diameter increment in the second year. The P. nigra 63/135 and P. nigra 62/154 clones had the highest (7.18 cm) and lowest (0.4 cm) of volume increment in the fifth year, respectively. The qualitative study of different P. nigra clones showed that except for the P. nigra 56/72 and P. nigra 49/23clones which had low and moderate curved trunks, respectively, the other clones had smooth and straight trunks.