A large, 40-year-old tree can pay back as much as $160 per year to homeowners and taxpayers in the American West, say researchers at the USDA Center for Urban Forest Research at UC Davis.

For example, said center director Greg McPherson, a 40-year-old ash tree in Claremont, Calif., would intercept over 4,800 gallons of stormwater, remove 6 pounds of air pollutants, reduce energy costs of cooling by up to 30 percent, and add 1 percent to resale value of a home. In contrast, the costs of that tree are considerably less, ranging from $28 for a yard tree to $36 for a street or park tree.

The benefits are detailed in a series of tree guides for the Western United States from the Center for Urban Forest Research. The guides are intended to describe the benefits and costs of planting trees for community officials and tree managers, and to increase public awareness and support for tree programs.

The fifth guide in the series has just been released: "Northern Mountain and Prairie Tree Guide: Benefits, Costs and Strategic Planting." The new guide was written for the "cold and snowy" climate region, which includes Northern California, Western Washington and Oregon, Alaska, Idaho, Montana, the Dakotas; Nebraska, Wyoming, Nevada, Utah, Colorado and the mountainous areas of New Mexico, Arizona and Southern California.

Future guides are planned for the San Francisco Bay Area and the desert Southwest climate regions. Already published are guides for the Inland Empire (which includes the Claremont example), South Coast and San Joaquin Valley climate regions of California, and the rainy Northwest climate region of western Washington and Oregon.

The Center for Urban Forest Research is a U.S. Forest Service program housed in the Department of Environmental Horticulture at UC Davis. Director McPherson is a UC Davis faculty member.