January 29, 2007


Farm friends John and Jim came by the other day to help tackle an oak thinning project.

Before we started

We have a strip of the native White Oak (Quercus garryana) that is growing along the south boundary of the farm. Historically, oaks grew in our area as widely scattered trees in a savannah; while the trees start as seedlings in thickets, fire tended to control their spread, and only large (and lucky) trees grew big enough to grow fire-resistant bark. In the absence of fire, local oaks become densely packed, and of small diameter. Thinning them gives them room to grow big and majestic as oaks should, and this go 'round gave us about a cord of firewood to split between us.

Allie guarding the spoils of thinning

We removed about a third of the oaks along one stretch of the stand. We got about halfway along the roadside, so there’s more to cut (another project day....), and I envision being able to do this at least every few years until we get the trees to a 30’ spacing or so.

After the project

Firewood is the main source of heat for our house...we burn about 2 ˝ cords of wood a year, in a mix of about 2/3 oak and 1/3 various softwoods. Oak has a BTU rating of 30,600,000, while cedar (our most commonly burned softwood) has 16,300,000 BTU (from woodheat.org).

While there are concerns about the sustainability of wood heating, our farm is working towards making it work for us for the long term. The 1400 trees we planted last winter, and the 2000 we’re working on putting in this year, will go a fair distance towards that goal.

Currently, we buy in most of our oak (1-2 cords/year, for about $175/cord), and scavenge downed trees from friends for the softwood. Our current forest has about 3 acres of 15 year old ponderosa pines, and we could start cutting from that. We’re waiting on that to allow for more growth, however, and allow our production to get further ahead of our needs.

I envision a significant amount of our future hardwood needs to be supplied by our extensive ash planting. Ash (~22,000,000 BTU) coppices well, so in a few years we’ll be able to start cutting the trees off low to the ground, and then coming back in a few years and harvest the suckers on a rotational basis, typically in a 6-15 year cycle. Our willow plantings will also work in this fashion, but it has a lower BTU value...we'll see if the increased growth offsets the lower heat value.

I’m still looking for data on fuelwood production....Oregon State doesn’t seem to have any hard numbers, but from other regions, the numbers vary from 1/3 cord per acre per year in Oklahoma(pdf warning), to a half or so cord in North Carolina and New York.. Our 3 established acres, with 6 more coming into production in a few years, should give us enough of a surplus to heat the homestead, and perhaps enough for additional dwellings (the beginnings of the theoretical Mossback Ecovillage...?)

Posted by rich at January 29, 2007 04:13 PM