New research estimates the value of Seattle’s urban forest!

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!


Within the Gradient: Introducing the Science of Green Cities

Our region exists across a dramatic gradient: from the peaks of the Cascades and Olympics to the Sound; from the wildlands of the National Parks and Forests to the urban cores of our cities.  This sphere encompasses all of our cities; our jobs and homes.  It also provides the spaces in which we interact with the natural world.  But a lot of questions about this interaction exist:

  • What value is nature to me, or to my community?
  • Is my environment in danger?
  • What impact do I have on nature in my city?
  • How can we improve the natural resources in our communities?

Since late 2009, the Green City Partnerships have been participating in a collaboration with a US Forest Service Research effort called the Green Cities Research Alliance.  This work is similar to exciting research that is being completed across the country like Chicago, NYC, and Baltimore looking at the interaction of people with ‘everyday nature’, in the places where they live, work, and play across the gradient.

It is important to understand the value of ‘green’ to all our landscapes, not only our forests and farms, but also the green in our cities.  Within our gradient we have a variety of types of landscapes, but also cities too!  We live in small towns and exurban communities.  And work in industrial centers and mixed use spaces.  We shop at malls, on mainstreets, and mom and pop’s.  Each of our communities can and does benefit from nature in their own unique way.

The Green Cities Research Alliance is conducting efforts to better understand this relationship of our cities with the natural world.  Research includes investigation of:

  • The people stewarding our parks and open spaces
  • The quality of natural habitats
  • Economic and other values of nature
  • Public health, and the benefits of outdoor restoration and recreation

Amazing work like this in the Pacific Northwest and elsewhere is springing up like crazy: check out this, and this, and this, and this here.   Green Cities Research Projects hope to uncover information about our interaction with everyday nature like these projects have, that can help our region thrive through health and stability, as well as provide data that is useful in cities across the country.  We will make an effort to keep you informed.  Please check back regularly for posts on the Science of Green Cities to see what we are discovering!