Effect of transplanting date and harvest method on growth and survival of three urban tree species in an arid climate.

摘要

The major challenges for transplanting trees in arid regions compared to temperate regions are higher mortality and slower rate of establishment. As such, date and method of transplanting can potentially improve survival and establishment as well as subsequent landscape performance of transplanted trees in arid climate. In the present study, three urban species commonly used in the Isfahan, Iran, landscape including eldarica pine (Pinus eldarica Medw.), white mulberry (Morus alba L.), and smoothleaf elm (Ulmus carpinifolia Gled.), were transplanted from January to June 2010, when mean air temperature was less than 10 degrees C (early winter), between 10 degrees C and 20 degrees C (early spring), or more than 20 degrees C (late spring). Half of the trees were bare root (BR) and half balled and burlapped (B&B). White mulberry and smoothleaf elm trees transplanted early in winter had the highest survival percentage over two years. The best survival for eldarica pine was observed in early spring transplanted trees. For all species, survival rate and trunk diameter increase of B&B trees were significantly greater than BR trees during the first year. Also, the first year's shoot growth and shoot number of pine trees, and dieback on elm trees, were significantly affected by transplanting method. During the second year, tree growth and survival for all species were similar for B&B and BR trees. Annual shoot growth of eldarica pine and smoothleaf elm trees, but not white mulberry, equaled to non-transplanted trees by the end of third year after transplanting, suggesting a species-specific response for post-transplant establishment in arid climate.