نوع مقاله : علمی- پژوهشی
نویسندگان
عضو هیأت علمی، گروه تحقیقات صنوبر و درختان سریعالرشد، مؤسسه تحقیقات جنگلها و مراتع کشور، تهران، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
After 3 years study on 25 fast growing poplar clones, selection was made for 7 clones of Populus deltoides and 3 clones of P. X. eruamericana all with great rooting ability, best height growth and pest and disease resistance. To determine the optimal spacing for highest yield, seedlings of selected clones with two year root and one year stem planted grouply (5×5 rows). Experiment was carried out for twelve years. Height and diameter at breast height (DBH) measured after each annual defoliation. Following final measurement, total volume was calculated by using two factors of height and DBH. The statistical technique of comparing the averages of volume was employed. The results of this investigation is as follow: The performance of five P. deltoides clones and two P. X. eruamericana with average DBH ranging from 16 to 19.7 centimeter and for 3×3 meters planting interval was measured as 20 to 32 m3/ha/year. Volume yield for 4×4 meters planting distance of five P. deltoides clones and two P. X. euramericana clones with average DBH of 21 to 24 centimeters measured as 20 to 31 m3/ha/year. For 5×5 meter planting distance a single clone from P. deltoides and one clones of P. X. euramericana showed average DBH of 23 to 24 centimeters and volume growth of 19 to 22 m3/ha/year.
کلیدواژهها [English]
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