When my wife and I bought our house, the yard was typical for
our neighborhood: a mostly barren plain of lawn so sunbaked that
you could bounce a tennis ball off it. So being eco-groovy
types, we’ve tried to improve the place: we put in a rain
barrel, built a natural drainage system, and added topsoil
planting berms. But I’m most proud of the trees we’ve planted: a
pair of akebono cherries in the parking strip and a white-star
magnolia in the front yard; and in the backyard, a shore pine, a
Chinese dogwood, a couple of vine maples, a Japanese maple, and
a limelight cypress. I recently began wondering how much carbon
our new trees are soaking up. Since tree planting is the sine
qua non of carbon offset programs, how much of my emissions are
offset by my yard? Enough, perhaps, to justify moving from a
dense highly walkable neighborhood to a still-urban but less
foot-friendly place? (My Walkscore dropped from 92 to 80.) The
answer, I’m afraid, is “no.” I estimate that in an average year
my nine trees will soak u