Location: Plant Introduction ResearchTitle: Evaluation of Native U.S. Trees at Purdue Author
Submitted to: Landscape Plant News
Publication Type: Other
Publication Acceptance Date: 2/15/2013
Publication Date: 2/28/2013
Citation: Mickelbart, M., Carstens, J.D., Daniel, K., Gosney, M. 2013. Evaluation of Native U.S. Trees at Purdue. Indiana Nursery and Landscape News. 73(1):22-25. Interpretive Summary:
Technical Abstract: Apart from our growing awareness of the potential risks of some invasive species, another reason for utilizing natives in the landscape is their ability to tolerate variable water availability once established (Dunnett and Clayden, 2007). Drought events are increasing in frequency in the U.S. (Barnett et al., 2004) and the identification of native species that maintain their appearance in a formal landscape under water stress conditions is important for the landscape industry and consumers (Brand, 1992; Locket et al., 2002; Kjelgren et al., 2000). Previously, we described the native shrub evaluation program at Purdue established in 2007 through the NC-7 program (Mickelbart et al., 2012). In this article, we describe native tree selections evaluated during the same time period. The objectives of the NC-7 (North Central project number 7) Regional Ornamental Plant Trials are to assess plant performance across a broad range of environments and climatic extremes and expand the range of useful landscape plants, while placing emphasis on detailed, long-term evaluations. The trials are one of the longest-running landscape plant evaluation networks in the U.S. Each year a small number of promising, new trees and shrubs are offered for testing to approximately 30 trial sites across 18 states. Plants selected for trial are acquired through plant explorations, seed or other propagule exchange, or direct donations from other institutions. Factors influencing plant selection include assessments of hardiness and aesthetics, ease of propagation and culture, naturalization potential, and specific interests of trial site cooperators. Introduced species are evaluated through this program, but a large number of the selections are native to the U.S. Trees are established in mulched rows, fertilized minimally each year, and irrigated as needed to avoid stress, especially during establishment. Once established, plants are observed and evaluated throughout the seasons at one, five, and ten years after planting. In addition to making a 10-year commitment to evaluate the plants, our goal is to keep them growing for the foreseeable future for evaluation and as a demonstration plot for anyone who wants to see how a particular selection is performing in central Indiana. This report provides descriptions on the NC-7 tree selections growing at the Purdue horticulture farm and their growth to date under the conditions described. Table 1 lists height and caliper measurements that were taken at the end of the 2012 growing season.