Forterra has long recognized the importance of Seattle’s urban forests, parks and green spaces. They provide amazing access to nature for the city’s residents, help curb pollution, cool the city, absorb carbon dioxide, and much more. It was because we recognized the significance of these trees that we helped launch the Green Seattle Partnership in 2004 with the City of Seattle and other local nonprofit partners. But, until recently, much of that value was derived from research on non-urban forests or anecdotal understandings of the contributions trees provide.
Now, thanks to the publication of Seattle’s Forest Ecosystem Values: Analysis of the Structure, Function, and Economic Values, which documents the findings of a multi-year research effort by the Green Cities Research Alliance (GCRA), Seattle has hard science about the monetary value of their trees and the impact they have on carbon sequestration, energy, pollution and more.
Data in the report was compiled using the USDA Forest Service’s i-Tree Eco tool, the first use in Seattle. Given the Pacific Northwest’s unique climate, ecosystem and tree species, Seattle was previously not well served by similar urban forestry research from other parts of the country.
Some of the most exciting findings from the report include:
- Seattle trees and shrubs are worth roughly $4.9 billion dollars (that’s what it would cost to replace them all)
- They save the city around $23 million annually in carbon storage, pollution removal and residential energy savings, establishing Seattle’s urban forest as an irreplaceable capital asset
- There are an estimated 4.35 million trees and tree-like shrubs in Seattle, which equates to a density of nearly 80 trees per acre
- The three most common species measured were red alder, big leaf maple, and beaked hazelnut, all of which are native to this region.
This research is based on field data collection from 2011 and 2012 in 223 1/10-acre research plots distributed on both public and private property throughout the City of Seattle. Crews recorded size and species information for trees and tree-like shrubs, as well as land use and ground cover information.
The Green Cities Research Alliance is comprised of people from Forterra, USDA Forest Service, University of Washington, King County, and the City of Seattle, all of whom contributed to the research. GCRA was initiated by the USDA Forest Service Pacific Northwest Research Station in 2009 to build a program of research about urban ecosystems in the Puget Sound region. GCRA pairs scientists with practitioners and local decision makers to co-design and implement research efforts that provide relevant and practical information.
Download a copy of the 26-page report to read about all of GCRA’s fascinating findings, our research methodology and more!