Urban forest assessment in northern Delaware

Abstract

Presents results of an analysis of the urban forest of the Wilmington, Delaware, the metropolitan corridor in New Castle County (NCC), and Rattlesnake Run sewershed in the city of Wilmington using the Urban Forest Effects (UFORE) model. This analysis reveals that there are about 882,700 trees (19.3 percent tree cover) in the NCC metro corridor and about 136,000 trees (16.1 percent tree cover) in Wilmington. The three most common species in the NCC urban forest are red maple (22.8 percent), sweetgum (16.9 percent), and black cherry (3.9 percent). In Wilmington, most common species are Norway maple (16.4 percent), northern white cedar (15.0 percent), and tree-of-heaven (9.5 percent). These trees store and remove a significant amount of carbon, reduce building energy use, and annually remove large amounts of air pollution. The UFORE hydrologic analysis of the Rattlesnake Run sewershed reveals that existing tree cover reduced nonsanitary flow by 1.4 percent during an August-to-February simulation period. Increasing existing tree cover over pervious surfaces from 5 to 45 percent reduced outlet flow by 1.7 percent; increasing tree cover from 5 to 45 percent over impervious land reduced flow by 10.7 percent.