Investigation on wood production of different poplar clones (wide crown clones) in Karaj area

In this investigation 15 superior poplar clones with wide crown were selected from the first stage of the Selection Nurseries Trial. One year old seedlings of the clones were planted under the statistical design of Randomized Complete Blocks at Karaj Natural Resources Centre in 1999 (75 seedlings at each plot). At the end of each growing season diameter at breast height (dbh) and height were measured. After calculating mean height and diameter of the clones, their mean, current and total growth volumes were determined. The mean growth volume data was analyzed using the MSTATC computer software. The results of 10 year old trial shows that among the investigated poplar clones, Populus euramericana vernirubensis with diameter of 24.6 cm and Populus euramericana 154 with height of 18.57 m achieved the greatest diameter and height growth rate, respectively. There was significant difference between P. euramericana vernirubensis and P. alba nivea in average volume growth rate (27.45 and 9.02 m3 /ha/y, respectively). During the 10 year growth period, the highest current volume growth of the poplar clones belonged to years 1996-1998, because 52.18 to 64.2 percent of the total growth developed during these three years. P. deltoides Particularly P. deltoides 73/51 was the most tolerant species whereas P. alba (P. alba nivea) and P. nigra (P. nigra 42/51) were the low tolerant species to pest infection