Pacific Northwest Research Station

Market Sector Analysis Team

2008 Science Accomplishments

The benefits of street trees in Portland, Oregon, far outweigh their costs

Portland's street trees are estimated to provide a $45 million-dollar benefit each year. Credit: Geoffrey Donovan

Does the size or type of tree in front of a home influence the home's sale price? This study found that crown area within 100 feet of the house, and number of trees fronting the house were significant. When combined, these two variables add an average of $7,020 to the price of a house in Portland, which is equivalent to adding 106 finished square feet to a house. Extrapolating to the entire city, the total value of Portland's street trees is $1.1 billion. When converted to an annual value, this translates to a $45-million benefit annually. For comparison, the city of Portland estimates that the annual maintenance of Portland's street trees costs $4.6 million.

In addition, these benefits spill over to neighboring houses-perhaps the most significant finding from the study. If home-owners have a tree outside their house, only about half the benefit goes to them. The remaining half spreads to neighbors within 100 feet. Currently,
homeowners bear all the costs of street tree maintenance. Because they do not receive all the benefits, individual homeowners are unlikely to plant enough trees to maximize Portland's urban tree potential.

This study was done in close collaboration with the city of Portland and has attracted interest from the Multnomah County Assessors' Office, State and Private Forestry, Oregon Urban and Community Forestry Program, and several local arborists and landscape architects. In addition, the cities of Tigard and Gresham, Oregon, have incorporated the study into their urban forestry plans. The study was also featured in the June issue of Portland Monthly and on Oregon Public Broadcasting.

Outcome: The cities of Portland, Tigard, and Gresham, Oregon, have incorporated the study's findings into their urban forestry plans.

Partners: City of Portland Urban Forestry Program, National Institute of Standards

To learn more, contact Geoffrey Donovan at gdonovan@fs.fed.us.