The presence of trees in neighborhoods is essential for maintaining cooler temperatures (reducing the 'heat-island effect'. The EPA defines heat islands as built-up areas that are hotter than nearby rural areas), reducing noise, and beautifying streets and parks. Trees also have profound environmental and health benefits, absorbing and filtering water run-off around paved areas and diluting air-borne pollutants. To learn more about the benefits of neighborhood tree coverage see the EPA fact sheet linked below.

This measurement is derived from the National Land Cover Database (NLCD) 30-meter national dataset. It represents the percent of total land cover within each block group that is tree canopy, whether in forests, along streets, or individual trees.

NOTE: Prior to June 2020, the Compass relied on National Agricultural Imagery Program (NAIP) data sourced from the EPA EnviroAtlas. This information reported only on the urbanized area of Durham County, and gave metric estimates which differed significantly from the current compass values (ranging from 5.8% lower to 33.4% larger on the blockgroup level compared with current compass values) . We moved to NLCD data in order to both extend the time series reported here - showing information for both earlier and more recent years - and to extend the area of coverage to the entire county. Comparisons to all areas of the contiguous US are also made possible by using NLCD data for these summaries.

Source: National Land Cover Database (NLCD), accessed via the Multi-Resolution Land Characteristics Consortium.