An Analysis of Species Selection and Acquisition Practices by Community Tree Planting Programs

Community tree planting programs, often managed by non-profit organizations or municipalities, improve communities with tree planting and management that frequently includes volunteer support. A recent focus of these programs is to increase the diversity of trees in the urban landscape to mitigate the risks associated with over planting, including devastating losses to species-specific landscape pests. However, a limitation frequently mentioned by practitioners is an insufficient species mixture available within nurseries. This study examined the tree selection and acquisition process in order to identify key organizational components contributing to tree planting goal attainment. Research included eleven, qualitative, key informant interviews with community tree planting program managers in the Northeast and Mid-Atlantic United States. Semi-structured interviews yielded data at each organization, and transcribed verbal qualitative data was analyzed at the response level. Additional data gathered during this study included approved species lists, site assessment checklists, contract specifications, and tree planting totals for 2008. Participating organizations reported an aggregated total of 26,383 trees planted during 2008, with the range of total planting activity between 44 and 21,025 trees during that same year. Zelkova serrata, Gleditsia triacanthos var. inermis, and Styphnolobium japonicum were the three most frequently planted species among participating organizations during 2008. Prunus (14.91%), Quercus (11.45%), and Zelkova (8.53%) were the most frequently planted genera, and the most heavily planted families included Roseaceae (22.59%), Fagaceae (11.67%), and Ulmaceae (11.14%). The species selection process frequently begins with the consideration of an approved species list. Organizations reported a combined total of 97 species approved for planting in their geography, and these approved species lists included, on average, 77.97% of all species planted by participating organizations during 2008. Findings indicate a variety of selection processes and criteria utilized to identify appropriate species for communities. Emphasized selection criteria included a species' native range, stress tolerance, mature size, and aesthetic characteristics, all of which contributed to the final mixture of species sought by the organization for planting. However, the ranking of these selection criteria varied significantly among participating organizations. Additionally, programs supporting community involvement and input in tree selection reported greater success with the tree acquisition process. Approved species lists, site assessment checklists, nursery specifications, and tree installation specifications were frequently reported as organizational components that supported the achievement of tree planting goals. Participants interacted with nurseries primarily through traditional and personal communication, although some organizations utilized bid solicitation or contract growing to obtain species from nurseries.