Welcome to Walden Pond, Fifth Avenue style. Isabella’s parents, Colin Beavan, 43, a writer of historical nonfiction, and Michelle Conlin, 39, a senior writer at Business Week, are four months into a yearlong lifestyle experiment they call No Impact. Its rules are evolving, as Mr. Beavan will tell you, but to date include eating only food (organically) grown within a 250-mile radius of Manhattan; (mostly) no shopping for anything except said food; producing no trash (except compost, see above); using no paper; and, most intriguingly, using no carbon-fueled transportation.

Mr. Beavan, who has written one book about the origins of forensic detective work and another about D-Day, said he was ready for a new subject, hoping to tread more lightly on the planet and maybe be an inspiration to others in the process.

Okay, so this is a project so he can write a book about it. Fair enough. But I had to do some calculations for myself to decide if going a year without toilet paper was worth it.

(I did warn you there would be math in this blog.)

After visiting various sites and pages (no Wikipedia), the following information has been gleaned:

- According to the manufacturers of Charmin, a roll of toilet paper lasts around five days. In my experience, it doesn't seem to last as long. So for my calculations, I'm going to say a roll will last 2 days. Given that assumption, in one year I will use 365 / 2 = 182.5 rolls.
- On average, a roll of toilet paper will weigh 227 grams, which is just a hair over half a pound. To simplify the math, let's call it a half pound even. So in a year, I will use 182.5 * .5 = 91.25 pounds of toilet paper.
- We can't really determine how much wood is produced by a single tree because of the variability in sizes and wood extracted, so there is another figure to define a "standard" amount of wood: a cord. A cord is defined as a pile of round wood 4 feet wide, 8 feet long and 4 feet high.
- We can produce 1,000 pounds of toilet paper from one cord of wood. Given our half pound estimate for a single roll of toilet paper, that means that I can produce 2000 rolls of toilet paper from a single cord of wood.
- That means that from a single cord of wood I have 2000 / 182.5 = 10.959 years worth of toilet paper. From a single cord.
- One nice little tidbit is that for each tree used for paper (and that means all types), five more are planted.

Plus, the one thing that drives me nuts about this discussion is that paper is a renewable source and that there are people gainfully employed in making paper. I really don't want to put them out of a job.