When the Governmental Accounting Standards Board was developing Standard 34 a decade ago, it decided not to require communities to declare the structural value of their trees.
From an accounting perspective, this makes sense: Unlike roads and sewers, trees appreciate. But in a holistic sense, the decision haunts us. Just when we need them the most — to mitigate the environmental consequences of our standard of living — our emphasis on manmade rather than natural solutions makes it easier to justify short-term gratification over a long-term solution like trees.
And that's unfortunate. Trees are the least expensive and most rewarding infrastructure investment a community can make. Even after subtracting costs related to planting, pruning, watering, removing, repairing curbs and sidewalks, and the occasional freak accident involving a dead or dying limb, a tree returns 2½ times the investment through higher property values, lower air and water pollution, and energy conservation.
Shaded pavement lasts longer. Trees lower crime rates. According to University of Illinois researchers, trees reduce domestic violence and help children cope with learning disabilities. Tree-lined business districts are more inviting and thus more successful.
If you're lucky, you've got a certified arborist or similarly credentialed professional on staff who can calculate the value of public trees to the community as a whole. These men and women wrestle with the same challenges you do. They've inherited assets specified by budget-conscious predecessors seeking the hardiest species for the lowest initial cost. Why go to the trouble of mixing things up a bit when a single variety can be planted over a large expanse?
I'm no Tom Thumb, but even I can foresee the pitfalls inherent in such a strategy.
If you don't have a certified professional on staff, don't despair. There are free tools for quantifying the return on investment in green assets. I suggest going first to the U.S. Forest Service's Midwest Community Tree Guide, a primer that addresses topics such as how, when, and where to plant trees for minimal negative impact on sidewalks, roads, and curbs.
Then I'd use another Forest Service tool — www.itreetools.org — to identify species that will best help achieve your community's goals after factoring in the costs and benefits related to its existing asset mix. Are you looking to remove air pollutants? Lower air temperature, ultraviolet radiation, wind, and stream flows? Store carbon? Improve building energy conservation? Modules of the i-Tree software suite calculate the long-term costs and benefits of existing and future plantings.
As usual when championing infrastructure assets, you'll have to become a teacher. Which means you may have to educate yourself first. But unlike potholes and parking meters, trees are an emotionally positive topic for most people. Put that passion to work.
? Stephanie Johnston,Editor in Chief
We search so you don't have to! For links to an analysis of trees and pavement performance as well as the Midwest Community Tree Guide, click here.