Unimproved right-of-way adds environmental value


An example of unimproved right-of-way

Have you ever noticed a street that ends abruptly in a greenbelt or wooded area, then starts again a block away?  The area where there is no street is most likely an unimproved right-of-way, and they are scattered throughout the city.  Many are overrun by invasive vegetation, but they are part of the urban forest.  The trees that grow in these areas contribute to the city’s canopy cover, but until now, we have had only vague ideas about their environmental contribution.   A recently completed Master’s Project fills in some of the blanks. Jake Milofsky, a graduate student in the School of Forest Resources at the University of Washington worked with staff in Urban Forestry to develop a project that inventoried trees and shrubs in unimproved right-of-way in the Central Area.  The inventory program he used, called I-Tree and developed by the US Forest Service, quantifies environmental benefits such as pollution reduction and carbon storage. 

Jake presented his findings at a recent Urban Forestry staff meeting.  He sampled 16 acres of unimproved right-of-way and the I-tree generated report “estimated that trees and shrubs remove 1 ton of air pollution (ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), particulate matter less than 10 microns (PM10), and sulfur dioxide (SO2)) per year with an associated value of $7.05 thousand (based on estimated national median externality costs associated with pollutants[2]).”   He also found that trees in the Central Area unimproved rights-of-way sequestered 24 tons of carbon each year. The results suggest that even small green spaces provide quantifiable benefits.