Post-transplant shoot growth of trees from five different production methods is affected by site and species.

摘要

After transplanting, many trees enter a period of reduced growth that may limit their environmental and aesthetic benefits for several years. A number of nursery production methods have been developed in attempt to reduce root disturbance, which is often associated with the reduced growth. The main objective of this study was to investigate how five nursery production methods affect root systems and post-transplant shoot growth. Other objectives were the study of the effect of root structure (i.e., fibrous verses coarse) on trees' response to different production methods and the effect of the conditions at the transplanting site. Sweet cherry (Prunus avium L.) and red oak (Quercus rubra L.) with a stem circumference of 16-18 cm were produced as bare-rooted-, balled-and-burlapped-, root-pruned-, air-potted-, or fabric-container-grown trees, transplanted at two sites and studied for five seasons. Visual analysis showed that the production methods had clear effect on the root balls at transplanting. However, the differences were not clearly related to shoot growth. All transplanted red oaks, regardless of production method, showed significantly reduced shoot growth compared to pre-transplant growth. Balled and burlapped, root-pruned, and fabric-container-grown sweet cherry trees exhibited restored pre-transplant shoot growth three years after transplanting at the more favorable site. The results suggest that the fibrous-rooted sweet cherry was more responsive to production methods designed to reduce transplanting stress than the coarse-rooted red oak, and that site affected the time required for normal shoot growth to be regained. The results do not indicate that different sites require differently produced trees.