The loss of ash (Fraxinus spp.) trees in the midwestern United States due to emerald ash borer has emphasized the need for more diversity in urban and community forests. However, nursery growers report that many Fraxinus spp. alternatives are difficult to transplant. Understanding the physiological reasons why one tree species has superior transplantability over another is an important factor in increasing production of Fraxinus spp. replacements. In this study, we examined five difficult to transplant ash alternatives; Celtis occidentalis, Quercus bicolor, Quercus ellipsoidalis, Quercus rubra, Taxodium distichum, and Fraxinus americana. To mimic nursery grower practices, trees were assigned at random to one of four treatments: 1) control, 2) heeled–in, 3) cold storage, or 4) sweating. After treatment, trees were assigned at random to one of three evaluations: root growth potential (RGP) test, container planting or field planting. Root growth potential was very low for Quercus spp. trees and varied by treatment for C. occidentalis. Taxodium distichum trees had a relatively high root growth potential in all treatments. Stem water potential measured immediately before and after pre–plant treatments suggest that Quercus spp. trees and T. distichum trees were able to rehydrate during sweating while water stress levels in C. occidentalis trees remained high. The results suggest that poor transplanting success reported for Quercus spp. trees may be related to low root growth potential, whereas poor success of C. occidentalis trees may be due to shoot desiccation during storage and handling.
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