Although a street tree's environmental and aesthetic value is seemingly immeasurable, the U.S. Forest Service has apparently quantified the value of a single urban tree at $2,500. Whether calculable or not, despite their benefits, the Forest Service found that American cities suffer a net loss of 4 million trees annually.
"The reasons for such a broad decline vary, according to Eric J. Greenfield, a forester for the U.S. Forest Service and co-author of the study," says Newcombe. "He mentions wind storms, drought, pest infestation, old age and removal as some of the key contributors. But the last problem cited might be the biggest contributor as cities continue to cut down trees to make way for new development."
So what can be done to reverse this decline? Cities such as New York and Boston have started tree planting campaigns, with varying success. Newcombe finds hope in other indicators:
"The good news is that our understanding of how trees benefit cities has been extensively documented, and more people are being trained in urban forestry. Software tools like i-Tree have been developed that can accurately assess and analyze an urban forest, and community groups continue to raise funds to pay for tree plantings."
"Hopefully," concludes Newcombe, "as cities emerge from the last vestiges of the Great Recession, we will see a revival of interest -- as well as investment -- in our urban canopy."