In a land of water, dwindling trees: for Puget Sound, dramatic tree loss sparks a call to action.

For Puget Sound, dramatic tree loss sparks a call to action.

When English Captain George Vancouver sailed through the Strait of Juan la Fuca and into Washington's Puget Sound, he found a hand and seascape of snow-peaked mountains, misty islands, and, everywhere, trees. Two hundred six years later, much of the region's forests have been lost to development in cities such as Olympia, Tacoma, Seattle, and Everett. A regional ecosystem analysis by AMERICAN FORESTS makes this fact - and its consequences - clearer than ever before.

In a Geographic Information System (GIS) analysis of a 3.9-million-acre area, satellite images from 1972, 1986, and 1996 show areas with high vegetation and tree canopy coverage (50 percent or more) declining by 37 percent. During the same 24-year period, areas with very low tree cover (less than 20 percent) more than doubled from 25 to 57 percent.

"While much attention has been focused on the rural forests in the Pacific Northwest, our study underscores the importance of also understanding what's happening in the region's growing urban areas," says study author Gary Moll, vice president of AMERICAN FORESTS' Urban Forest Center.

Urban trees perform valuable services not easily replaced by costly manmade alternatives. Trees, vegetation, and natural soils slow stormwater movement, lower total runoff volume, and reduce costly flooding. It's no surprise, Moll says, that Puget Sound's tree loss increased runoff during a peak storm event by 29 percent, an estimated 1.2 billion cubic feet (equivalent to 16,218 Olympic-sized pools). Building retention ponds and reservoirs for excess water would cost about $2.4 billion.

Air quality control costs have also grown. The lost tree canopy would have removed about 35 million pounds of pollutants annually (a value of approximately $95 million). City forests improve air quality by removing nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone, and some particulate matter.

Trees and Salmon

Another consequence of dwindling tree cover is the degradation of streams important for healthy fish populations. That's especially alarming in the Northwest, where salmon are a prized resource. Streamside forests improve fish habitat by cooling the water and filtering sediment and pollutants. That's important not only to the fish, but to the region's economy, which depends on salmon fisheries.

The wake-up call was not lost on the residents and leaders of this outdoor-oriented area. The mayors of Seattle and nearby Bellevue embraced many of the report's recommendations.

One suggestion was that Puget Sound decisionmakers use the analysis for regional planning and growth management. Communities can do this by conducting detailed neighborhood-level analyses, like the one now being done by Bellevue in conjunction with AMERICAN FORESTS (see "Saving for a Rainy Day," pare 24). AMERICAN FORESTS also recommends that cities strive for 40 percent tree canopy coverage overall (see "America's Urban Forests: Growing Concerns," Autumn 1997).

AMERICAN FORESTS has joined the effort to restore the Puget Sound watershed through its Global ReLeaf 2000 campaign, and this fall will launch a regional tree-planting effort. Planting trees will help restore the clean air, water, and wildlife habitat that make the Puget Sound region such a wonderful place to live.

Craig Noble is AMERICAN FORESTS' communications specialist.