As our local government tries to determine whether or not trees are valuable enough to protect, our urban flooding issues remind me that the trees are way more valuable that we give them credit for.
How do trees help quell urban flooding? Well, for starters, if there's a tree in a space, there's probably not concrete or asphalt there. Water hits impervious surfaces like that and flies off, following gravity's lead. One average-sized parking lot can experience 27,000 gallons of runoff in one average-sized summer storm.
Think about that for a minute; that's a lot of water heading toward a gutter near you, getting backed up, pushing out into the street and into people's homes.
But if the trees and bushes and grass were there instead of concrete or asphalt, the water could penetrate the ground, and some of the water — and the pollution in it, too — would get sucked up by plants' roots.
The natural ground literally slows the flow of water, so our drainage system and creeks (which are nature's drainage system) wouldn't get so backed up so quickly.
So, how valuable is natural space? Answer that question by answering these questions: How much do all of these floods cost us? How much does pollution cost us? (Note: Not only can plants pull it out of water, they can also pull it out of the air.) How much do the heath issues caused by pollution cost us?
We could do this all day, but, instead, maybe you should read about "Nature's economist," Dr. Gretchen Daily, in The New York Times instead:
“We are working to very specifically quantify in biophysical and dollar terms the value of conserving the forest and its wildlife,” she said.In recent years, Dr. Daily has expanded her research to include a global focus. She is one of the pioneers in the growing worldwide effort to protect the environment by quantifying the value of “natural capital” — nature’s goods and services that are fundamental for human life — and factoring these benefits into the calculations of businesses and governments.
Read the rest of this article, by John Moir, here. (Subscription may be required.)
Further reading: NC allows Duke Energy to burn trees for energy — Clean Energy Footprints