What's a Tree Worth?

Laura Bliss reports on the work of David Nowak, a lead researcher at the U.S. Forest Service’s Northern Research Station in Syracuse, New York, and one of the founding developers of the Forest Service's i-Tree software programs.

The i-Tree system uses GIS and a complex set of algorithms, to provide "detailed inventories of their urban canopies, and calculate their dollar value." Bliss details how the i-Tree program worked for a study of Austin's urban forest in 2014 [pdf]:

A recent i-Tree analysis of Austin, Texas, led by Nowak, estimated that trees save that city nearly $19 million annually in reduced building-energy use, some $5 million in reduced carbon emissions, and account for about $16 billion as standalone physical assets. Past that, they’re worth $3 million per year in their reduction of air pollution (based on avoided respiratory health problems), and nearly $12 million per year in the amount of carbon they sequester.

The i-Tree system has been collecting new metrics since it was first released in 2006, but Nowak is still working to add more ways to quantify the benefits of trees. "Right now, some of Nowak’s work is focused on calculating the dollar value of the reduced air temperatures and absorbed UV radiation that trees provide," according to Bliss.

The article includes more about the additional potential for the i-Tree program, as well as additional findings the program has revealed about urban forests around the country.