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Near Road Tree Cover in the Portland, ME EnviroAtlas Community Area
Citation:
Sears, A., L. Jackson, AND T. Wade. Near Road Tree Cover in the Portland, ME EnviroAtlas Community Area. Presented at Yale Urban Ecosystem Services Symposium, New Haven, CT, January 24, 2014.
Impact/Purpose:
To communicate ecosystem services information available in EnviroAtlas at neighborhood scales that can facilitate decisions involving urban green infrastructure.
Description:
Internationally, local air pollution from busy roadways is a significant issue for public health. Recent studies have shown that having tree cover between highly-traveled roads and people living, working, and going to school nearby can help to mitigate pollution and potentially reduce the related adverse health effects. These maps are part of the US Environmental Protection Agency’s EnviroAtlas, which is an effort to illustrate a variety of ways that the built and natural environment can support human health and well-being. The community component of this project involves producing high-resolution data, maps and metrics in selected US cities and adjoining rural areas. Among the factors being mapped is the amount of vegetation near roadways, and the population living along heavily-traveled roads. Land cover was classified from 1-meter resolution aerial photography, and was then used to quantify the amount of tree cover along interstates, arterial roads, and connectors within a focal community. The amount of tree cover within twenty-six meters from the edges of these busy roadways was calculated using a moving window approach. The final products include both a visual representation of the near-road tree cover summarized into five percentage classes, and a summary at the Census block-group scale of the population with and without significant tree buffer. A minimum threshold of 25 percent tree cover per moving window analysis unit represents a ten-meter-wide tree buffer, which is estimated as potentially sufficient for mitigating traffic pollution under ideal environmental conditions. In combination with demographic data, this map can be used to identify portions of the city that may benefit from enhanced tree cover near busy roads. Areas of concern include schools, day-care centers, retirement homes, and neighborhoods where high proportions of the population are particularly susceptible to vehicular air pollution.