The value of trees


Tree-lined path at Marine View Park in Normandy Park

by Amanda Leon

Amanda Leon is a former City of Normandy Park’s Community Development and Parks Director, and a certified arborist. This is an excerpt from an article that originally appeared in the May 2015 edition of Normandy Park City Scene.

In 2006, the U.S. Forest Service launched i-tree, an open access free software program to collect and quantify urban forest data. The current version uses groundwater capture, energy savings, air pollution benefits, carbon sequestration, homeowner value, and pest detection. One of its most powerful tools is a national tree benefits calculator. i-tree has developed this tool for anyone to use. The calculator provides an overall benefits value for each tree on your property. Simply go to, enter a zip code and follow the instructions. By selecting tree species, estimating the tree’s diameter, and selecting a property type, the tool will calculate an estimated annual benefit and provide benefit descriptions that quantify the following:

  • Trees Reduce Storm Water Runoff
  • Trees improve Water Quality
  • Trees Reduce Atmospheric Carbon Dioxide
  • Trees Improve Air Quality
  • Trees Save Energy

For example, a 20″ diameter Douglas Fir provides $195 in annual benefits, a 15″ Red Alder provides $95, and that 10″ Flowering Magnolia provides $44 worth of benefits. Add up all of your trees and you have a new nest-egg. Many Normandy Park residents have thousands of dollars of valuable trees and didn’t even know it. Seattle is in the top 10 U.S. cities with the largest urban tree canopies. According to American Forests Organization, there are 192 tree species, 28 of which are native to Puget Sound. The most common tree species are Red Alder,  Big Leaf Maple, and Hazelnut, all of which are native. In Seattle, the value of the urban forest is $4.9 billion. Their trees annually store 2 million metric tons of carbon, sequester 14,000 metric tons of carbon and remove 725 metric tons of environmental pollution valued at $5.6 million. They also reduce building energy use by $5.9 million.

Normandy Park, although smaller in size, still can boast the benefits of trees. Maintaining your woody assets helps secure your investment in your home and community. Please, explore i-tree’s national tree benefits calculator to find out the value of your trees today!

Posted 8/6/2015