مطالعه رشد و عملكرد نهالهاي ريشه لخت و گلداني كاج تدا )PINUS TAEDAL.( پس از انتقال به عرصه جنگلكاري

Growth and performance of bare and pot rooted seedlings of Loblolly pine (Pinus taeda L.) after plantation.

Seedling production of P. taeda in plastic bags is economically more expensive than bare-rooted method due to limited space for root development (root rotation) and its negative effects on subsequent seedlings growth and performance at field. The aim of the study was to estimate the mortality of the bare-rooted seedlings, particularly after planting at field. The hypothesis was that if the seedling production, transportation and plantation perform in adequate method and time, there will not be significant differences between the bare and the pot rooted seedlings survival and growth. The trial consisted of two stands of P. taeda seedlings (each containing 60 seedlings) with 2x2 m Spacing. The bare and pot rooted seedlings were planted at each stand, separately. The growth and survival parameters were measured annually up to three years at end of growth period. The results showed that although height growth of the pot rooted seedlings was significantly more than the bare-rooted seedlings up to two years after plantation, but there was not significant difference at third year. The collar and breast height diameter of the pot-rooted seedlings was significantly more than the bare-rooted seedlings, where as the quality of the bare-rooted seedlings was significantly better than the pot-rooted seedlings. Moreover, survival of the bare-rooted seedlings (75%) was slightly less than the pot-rooted seedlings (88%).