For urban dwellers, trees soften a city’s hard edges and surfaces, shade homes and streets, enhance neighborhood beauty, filter the air, mitigate storm runoff, and absorb carbon dioxide. Trees may even reduce crime and improve human health. However, these benefits have not been well quantified, making it difficult for urban planners and property owners to weigh their costs and benefits or assess tree cover against competing land uses. New research from the Pacific Northwest (PNW) Research Station demonstrates that street trees increase home prices in Portland, Oregon, that shade trees reduce household energy use in Sacramento, California, and that these effects can be measured and expressed in dollars. A study led by economist Geoffrey Donovan, research forester with the PNW Research Station, determined that trees planted on the south and west sides of Sacramento houses reduced summertime electricity bills by an average of $25.16. In a second study in Portland, Donovan’s team found that street trees growing in front of or near a house added an average $8,870 to its sale price and reduced its time on the market by nearly 2 days. These economic benefits spilled over to neighboring properties: a neighborhood tree growing along the public right-ofway added an average of $12,828 to the combined value of all the houses within 100 feet.
Wells, Gail; Donovan, Geoffrey. 2010. Calculating the green in green: What's an urban tree worth? Science Findings 126. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 5 p.