What is a tree on a city street worth? More than you might expect when you take into account all the benefits that trees provide in the urban landscape. This is what Alejandro Chiriboga, an Ohio State University (OSU) graduate student, discovered when he evaluated trees in the city of Wooster, Ohio using special software developed by the U.S. Forest Service.
Chiriboga started out by inventorying and recording the attributes of 3,229 municipally owned trees in Wooster in the summer of 2010. He then used the Forest Service's i-Tree Streets software to calculate the environmental value the trees provided by storing carbon, removing air pollution, helping to deal with stormwater, and conserving energy, along with the more traditionally recognized aesthetic benefits. His conclusion? Each tree provided about $83 dollars in benefits annually, for a whopping $270,153 value overall to the city! This is in addition to the value of the 3,980 tons of carbon stored in the trees' aboveground tissues, which wasn't figured into the annual values noted above.
Research has shown that the more mature and well-established the tree, the greater its contribution in environmental improvement. Trees that are 20 years or older have been shown to have the greatest benefits in terms of carbon removal and storage and removal of dust particles and carbon monoxide from the air. This underscores the importance of assessing the health of existing trees and finding strategies for keeping city trees thriving in a stressful environment.
That's where i-Tree comes in. This state-of-the-art software suite was developed by the U.S. Forest Service to help communities make the most of their street trees. In the public domain so that it is available to all, i-Tree offers various urban forest assessment applications, as well as tools for selecting proper species, detecting pests, and assessing storm damage. i-Tree can help anyone interested in urban forest stewardship assess and manage anything from a single tree to an entire forest.