The Power of a Tree

Despite my love of National Geographic and of recycling, you won't
often find me among the tree-huggers. But I am starting to love trees
more, and let me tell you why. Not only are they pretty to look at,
but there are all sorts of cold-blooded benefits to having them
around. Here are three, taken from a blurb in a Penn periodical about
a recent greening symposium that took place on campus:

* Improves stormwater management. Most buildings are considered, in
design parlance, impervious, meaning that when it rains, there's
nothing to soak up all that water. Too much grey and not enough
green, and you get a lot of flooded basements. In contrast, one
California oak tree with a canopy of 100 feet across can hold 57,000
gallons of water during a flash flood. That's a lot of water being
soaked up and used to produce pretty leaves instead of creating
flooding problems.

* Improves property values. One of my colleagues at work recently
co-published a paper in which it was found that while proximity to a
neglected vacant lot subtracts 20 percent from the value of a
neighboring home, being near a stabilized, "greened" lot can add 15
percent. In fact, the City, through its Neighborhood Transformation
Initiative, has been doing a lot of this converting of eyesore lots
into temporary mini-parks, not just because of the aesthetic benefits
but the fiscal ones: higher property values mean more property tax
revenues.

* Improves urban attractiveness. Parks and outdoor spaces are a huge
draw for our (increasingly mobile) knowledge workers as well as for
domestic and foreign visitors. Sprucing up, then, can translate into
net inflows of tourists and residents, which breaks our cities out of
that vicious cycle of population loss and infrastructural decay and
into a virtuous cycle of population gain and increased vibrancy.

So the next time a tree-hugger asks me to join in on a tree planting,
I just might join in. Just not necessarily for the same reasons as
the tree-huggers.