Valuing Trees, In Dollars and Sense

Appreciating the value of trees is not something I’m generally moved to assign a dollar value to.
This being mid-summer in New York’s verdant mid-Hudson valley, it’s usually because I’m looking for some shade, or just enjoying the wonderful effect on the human nervous system of the subtle sights and sounds when they interact with the wind.

So it was a pleasant surprise to see this post in the Boston Globe’s Business Filter, where that blog’s evergreen Maura Welch pointed to an Economist story, "Green Gold," on this particular branch of cost/benefit analysis.

“Following the trend of putting the 'eco' into economics,” she writes, “New York mayor Michael Bloomberg recently did a tree census. The value of the city's nearly 600,000 trees? $122 million.”

Hizzoner the Mayor arrived at that number by adding up estimates for filtering pollution, saving on air conditioning, stemming storm-water run-off, and even for “aesthetic benefits” (which I think would be expressed more convincingly by my proposed "nervous system relief quotient," above. In order to get that one to fly, though, I should really acronymize it, i.e., as "the NSRQ"… but I won’t).

More “shady” numbers are offered in The Economist’s story: a sign spotted at a University of Texas construction site announces,

“The replacement value of this oak tree is $90,000.” The Economist writes, “The trees in American backyards may be worth far more than the cars in the front drive,” and that, “the Forest Service values the urban canopy in all of America at $14.3 billion.”

They summarize the value of these price-per-leaf exercises with, “By claiming that every $1 put into New York's trees returns $5.60 in benefits, (Bloomberg) may find it easier to galvanise New Yorkers to plant more and chop down fewer.”

You know, if that’s what it takes to get people to understand the truly incalculable worth of trees, then by all means, fire up that spreadsheet!

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Ironically, I saw this Associated Press story on the same day, in the same "paper" (since this was online Globe) --

“Man disguised as tree robs bank”

MANCHESTER, N.H. (AP), 7/8/07 --A weekend bank robbery involved multiple branches -- of the leafy variety.

According to police, a man with tree branches duct-taped to his head and torso walked into a Citizens Bank just as it opened Saturday morning and demanded cash from a teller. Police said the disguise was the most bizarre they'd ever seen.

"He really went out on a limb," Sgt. Ernie Goodno said Sunday.

Related, here:
15 Houseplants Can Reduce Indoor Pollution

The "Greenest" Cities