Sustainable firewood

14 Aug 2011 by Jim Fickett.

A back-of-the-envelope calculation suggests that when fossil fuels start to get much more expensive, forests in the US will be under considerable pressure, especially near population centers.

It would not surprise me to see fossil fuel prices five to ten times higher in 20 years (that is not a prediction; this is just a thought experiment). If something like that were to happen, heating with (renewable) firewood would become more popular.

I've wondered in the past whether a much higher US demand for firewood could be sustained. Researching the pine beetle caused me to run across the kinds of data needed to get an answer.

There are about 100 million households in the US, in round numbers. Climates vary a great deal nationwide, but perhaps 2 cords of firewood per household per year would be a reasonable average requirement.

Sustainable wood yields vary greatly by climate, soil, and tree species, but some quick searching suggests a typical value might be half a cord per acre per year. So 4 acres of forest could provide sustainable heating for a household. If everyone were to heat with wood, that would take 400 million acres.

There are between 700 and 800 million acres of forest in the US.

Obviously there is a lot of slop in this calculation, trees are used for many things besides firewood, and there would never be a complete switchover from fossil fuels to wood. Still, the calculation suggests that demand for firewood could be on the same scale of what the total forest in the country could provide.

Given that, it would, in reality, be local geography that determined outcomes. Trucking wood from Alaska, where it is most plentiful, to the big cities, would not be an option, particularly if oil were very expensive. So big population centers would mostly be out of luck, and any forest nearby would be under heavy pressure. On the other hand, those living in locations with few people and many trees, like Maine, Alaska and Montana, would probably have an affordable and sustainable heat source.

Something to keep in mind when deciding where to live for the long term.