Clark Williams-Derry does a back-of-the-envelope calculation here,
… on an annual basis, we can expect an acre of regrowing coastal forest to capture and store about two to three tons of CO2 per year.
How much is that? Counting gasoline, diesel, coal, natural gas, jet fuel, and minor petroleum products, the average Northwesterner puts about 12 tons of CO2 into the atmosphere each year…
So just to capture my personal share CO2 emissions from fossil fuels, I’d have set aside and restore at least 4 acres of clearcut coastal rainforest.
Our maps of clearcuts on the Olympic pensinsula showed that about a million acres of forestland were cut between 1971 and 2002. All of which means that the carbon captured by the regrowing forests is offsetting the fossil fuel emissions from at most 250,000 of the state’s 6.4 million residents. At most.
Anything helps — a 4 percent offset from fossil fuel emissions is better than no offset. But given that the Northwest’s coastal forests sequester carbon better than just about any ecosystem on the planet, it’s not nearly as much as I had hoped or expected.