Planting Native and Assisted Migration Oak Species in Southern New England: Preliminary Results

Christopher C. Riely, William J. Walker, Deanna Phan, Robert T. Fahey, Amanda Bunce, and Scott R. McWilliams

Published May 2025 in International Oaks No. 36: 95–106

Abstract

We established a planting trial to compare the performance of several native and assisted migration candidate non-native oak species over a 5-year period in a natural upland forest setting in Rhode Island, USA. This study is among the first of its kind focusing on oaks and assisted migration in the region where North America’s oak-dominated forests extend farthest to the northeast. Results from the first growing season contradicted our hypothesis that native seedlings would perform better than non-native species in current conditions, with the non-native species exhibiting higher survival rates and greater height growth overall. Species rather than initial height or diameter was the most important factor in determining the performance of the oak seedlings, which suggests that careful selection of oak species is important to the early success of a planting project. The survival and growth of the most successful species is likely partly explained by their range of habitat tolerances matching well with site characteristics and seasonally dry weather conditions. Although the seedlings have not yet lived through their first winter, early results show most of these nursery-sourced oaks surviving in unproductive soils, with the non-native species not only keeping pace with the natives but growing somewhat better. Practical lessons gained from this oak adaptation planting will inform best practices that can benefit future efforts in the region and elsewhere.

Keywords

adaptation, climate change, tree planting, Quercus, tree seedling, silviculture

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