Well, it’s not intuitively obvious. Folks with an environmental bent—and if you’re reading this, it’s a pretty good bet that you’re one—just plain love trees. Trees scrub pollutants out of the air, soak up CO2, release moisture and oxygen into the atmosphere, control erosion, protect watersheds, enrich the soil, reduce the air temperature, and provide habitat for other plants and countless animals. And they’re beautiful. Trees are the green plants that put the green in the Green Movement. Harvesting and burning firewood kills trees and releases greenhouse gases into the air. In urban areas subject to smog, wood burning contributes particulates to the already unhealthy mix. So it’s no wonder that the very idea of felling trees so we can cut ‘em up and chuck ‘em into the woodstove elicits a wince from so many environmentally minded folks.
So why heat with firewood? A pioneering study released by the Australian Greenhouse Office (AGO) in 2003, “Greenhouse Gas Emissions from Firewood Production Systems,” modeled the greenhouse gas emissions from wood fuel and compared it to the emissions resulting from the use of other fuels. The study considered not just the emissions from the burning of the fuel, but also the emissions created by the supply chain that converts the raw fuel at its source into useful energy at its eventual destination. The conclusion: Burning firewood results in lower greenhouse gas emissions than coal, natural gas, coke, fuel oil, or electricity generated from fossil fuels. And not just a little lower. The AGO study found that in the likeliest scenarios for firewood collected and harvested from native forests and woodlands, wood-burning results in about one-third to one-tenth of the greenhouse gases released by the use of natural gas, the next-cleanest fuel considered in the study.
Firewood is a renewable resource. We can grow trees, but when we use that last barrel of crude, there won’t be any more. The harvesting of trees for firewood, done as part of a sensible forest-management plan, can improve the overall health of a forest not degrade it, reduce the danger of wildfire, and promote biodiversity. And firewood is relatively cheap. For example, in my area (southern New England), a hundred gallons of fuel oil at this writing costs about $240. It should yield about 12 to 13 million BTUs of actual heat in your home, depending on the efficiency of your heating system. A cord of hardwood, cut and split, currently costs about $225 delivered (it’s only about $100 a cord if you buy whole logs and cut and split them yourself), and should yield about 15 to 16 million BTUs, again depending on the efficiency of your system. And wood heat much cheaper if you cut your own. My firewood permit on the watershed property of a local utility company will cost me $40 next year, and I’ll then pay $25 per cord for the five cords I’ll need for the year. I’ll also spend a little more than a hundred bucks on chainsaw parts and maintenance, miscellaneous tools and tarps, chain lubricant, and gas for the saw and the pickup. Altogether, it costs me about $275 to keep my home warm and cozy through a New England winter. Yes, it takes time and sweat, but I’m a middle-aged guy who sits in front of a computer screen most of the day, and I need the exercise.
You have to burn wood right to make all of this work for you and the environment. Wood needs to be fairly dry to burn well and to keep those precious BTUs from literally going up in smoke. About 20 to 25 percent moisture by weight is about right for firewood. Most wood when cut or collected in the forest will start out with a moisture content of about 45 to 50 percent by weight. Your wood needs time and proper storage for drying. Winter and early spring are the best seasons to put up firewood for next winter. Stack it outside, off the ground (recycled wood pallets work great), and in a sunny place. If you live in a damp climate, cover the top of the stack to keep the rain off, but leave the sides of the stack open so the moisture can escape as the wood dries. Even if you buy your firewood cut and split, get it early in the year. No matter what the newspaper ad says about “seasoned” firewood, it’s almost always delivered too wet to burn well.
You’ll need a good woodstove. Open fireplaces are amazingly inefficient, typically providing only about 10 percent of the heat from your firewood as warmth in your home. The other 90 percent goes up the chimney. Modern woodstoves and fireplace inserts will typically provide between 65 and 80 percent efficiency, and are designed to burn cleanly and with very little smoke—provided that your wood is properly dried!
Tags: Greater Outdoors
