What’s a trillion leaves more or less among friends?

Last year, in the spirit of finding something to write about when news gets slow over the holidays – no, wait, I mean in the spirit of providing a unique and innovative service to readers – I did something that I have never seen done before: Calculated how many “peepable” leaves exist in New Hampshire.

The answer as you may recall (although I bet you don’t) was 608 billion leaves on the state’s sugar maple, yellow birch and beech trees.

All well and good. But last weekend, as I hauled the umpteenth tarp of leaves to the compost pile, the number began to seem low, because I had raked at least 3 billion leaves myself. So I decided to re-examine last year’s analysis.

I started out noting that Nashua’s landfill collected 6,900 tons of “soft waste,” which includes grass clipping, in a year. I guessed that the total was one-third leaves and that each leaf weighs one-tenth of an ounce, which meant 736 million leaves taken to the landfill in Nashua each year.

(OK, so maybe I don’t have 3 billion leaves in my yard.)

This was interesting, but a dead end: I didn’t know how to extrapolate the results from a single built-up city onto a well-forested state. So I tried a different tack.

I found that the U.S. Forest Service’s New Hampshire’s Forest Resources estimated 4 billion live trees in New Hampshire in 2006 that were 1 inch in diameter or bigger, and that one-sixth of the forest land in the state is taken up by sugar maple, yellow birch and beech trees, which are the heart of peeping targets. That makes roughly 670 million “peep-able” trees.

Unfortunately, the Forest Service only cares about logging, not leaf peeping. It estimates only “dry biomass,” which includes trunks and branches, not “foliar biomass,” which is just the leaves. That wasn’t any help.

Finally I went to work by asking Jennifer Jenkins of the University of Vermont, whose top research topic is “measuring and monitoring forest carbon” via measurement of foliar biomass growth, plus some number-crunching by people at the Forest Service in Durham who asked not to be identified, probably because they should have been doing something useful instead of answering my ridiculous questions.

These combined to the conclusions that there are 0.73 tons – 1,460 pounds – of leaves per acre of sugar maple, birch or beech trees.

Multiply that figure by the 2.6 million acres of maple/beech/birch in New Hampshire estimated by the Forest Service, and you get 1.9 million tons of peep-able leaves. At a tenth of an ounce per leaf, a little calculator-punching found an estimate of ...

Wait a second – not 607 billion, as I reported last year, but 607 trillion! In the process of going from tenths of ounces to tons, and working in acres, my calculations last year were off by a factor of (gulp) 1,000!

If that isn’t an argument in favor of the metric system, I don’t know what is.

Anyway, if I ignore the fact that this error makes me look like an idiot, it is kind of good, because last year’s estimate was the same as saying each tree had roughly 800 leaves per tree, which is way too low.

This new figure is the equivalent of 800,000 leaves per tree, which might be a tad high but is within the margin of error for the usual estimate for deciduous trees.

So there you have it: New Hampshire is even more beautiful in autumn than I realized, by a factor of 1,000.

But now it’s almost December: Time to move to our next beautiful period. In other words, ditch the warm weather and let’s see some snow!

GraniteGeek appears Wednesdays in The Telegraph, and as a blog online at www.granitegeek.org. David Brooks can be reached at 594-5831 or dbrooks@nashuatelegraph.com.