Portland, New York City, Milwaukee and Atlanta are among the cities that have quantified the payoff from pines and palms, olives and oaks. It’s part of a breakthrough in thinking among city planners in recent decades who now realize that a city runs not just on engineering, but on biology and ecology as well.
What’s a tree worth?
Tampa, Florida demonstrated that kind of thinking in moving its leading tree official, Kathy Beck, from the Parks and Recreation Department onto its chief planning team. Tampa approaches trees as part of a green public works system, the living equivalent of roads and bridges. It’s a case of what Beck calls “green meets grey.”
Part of how Tampa gets it right on trees is that planners can shield themselves from partisanship, protest and profit motives by relying on science to decide on what, where and how many trees to plant…”
To get the biggest bang for tree planting and maintenance bucks, Tampa turns to my colleague, University of Florida Institute of Food and Agricultural Sciences urban forester Rob Northrop, for information on which trees provide the greatest shade, which can be planted closest to sidewalks and parking lots without root growth buckling pavement and which species best withstand floods in a city already impacted by sea level rise. University of Florida scientists Michael Andreu, Andrew Koeser and Paul Monaghan and the USDA Forest Service’s Geoff Donovan have also provided valuable expertise.
Northrop and other natural resource scientists see intrinsic value in trees. But he recognizes the tremendous economic pressures communities are under, so he and economists collaborate to get at the straight-dollar costs and benefits.
The most recent study of Tampa’s trees estimated that they save the city nearly $35 million (U.S.) a year in reduced costs for public health, stormwater management, energy savings, prevention of soil erosion and other services.
Drilling down even further, the University of South Florida has begun mapping individual trees. So planners know, for example, that the live oak on the 4200 block of Willow Drive has a 38-inch diameter and a $453 annual payoff…”
