In undeveloped areas, trees improve air quality, provide shade and habitat for wildlife, and help prevent erosion. But in urban areas, trees are also extremely valuable, lessening the “heat island” effect, reducing summer heating costs, sequestering carbon, intercepting airborne pollutants, and reducing stormwater runoff problems. Yet it can be difficult to determine existing and potential open space areas and to analyze how urban green spaces relate to each other.

Such mapping also helps to determine the location of existing urban parks, other public lands, large land holdings of nonprofit organizations, and connective corridors, such as greenways, hiker-biker paths, primary street tree corridors, and riparian forest buffers. These assessments include potential opportunities for green re-investment, including potential brownfield sites, vacant lots, and properties scheduled for demolition.

A recent IKONOS project studied Baltimore‘s tree canopy, in which it was determined that the tree canopy reduced the city’s energy use with a net energy saving of $3.3 million per year and avoided carbon emissions from power plants due to building energy conservation at an estimated 9,300 metric tons of carbon per year. Baltimore’s trees also remove about 10,800 metric tons of carbon per year at a value of $219,000 annually and remove about 700 metric tons of air pollution per year at a value of $3.8 million annually.