Although heating your house might not be the first thing on your mind in the middle of August, it is actually a good time to buy firewood. That's because wood is usually cut in the winter, when leaves are off and sap isn't running, notes Seth Spalding of Spalding Timber in Woodstock, CT. It then needs to dry out for least six months before your burn it.

Wood is porous. Wet wood is easier to saw. After the hurricane of 1938, people cut up excess downed wood and sank it underwater to preserve it until they could saw it into lumber. Paul Spalding told his son Seth that Morse Pond was so full of timber in 1939 that you could walk across it.

But wet wood is not good for burning. The more moisture in wood, the less efficiently it burns. Burning green wood can also cause creosote to gum up your chimney or stovepipe, which can spark a dangerous chimney fire. Freshly cut wood can be 60% moisture by weight - 25% or less is best for combustion. Be sure to cover firewood with a tarp, and leave at least six inches of air space between each pile to keep it dry.

Because new trees can be planted when older ones are cut, firewood is considered a renewable source of energy. That does not mean that it can't cause pollution. When wood is burned, gases and particulate matter are released into the atmosphere. During a typical wood heating season, wood smoke can account for about 80% of the air pollution in residential areas in some parts of the U.S. (Source: EPA) From this standpoint, natural gas, propane, wood pellets and oil are actually cleaner alternatives to wood. To reduce air pollution by 50-60%, replace any pre-1988 stove with an EPA-certified wood stove or fireplace insert. Burn clean, dry, seasoned firewood in small, hot fires. NEVER burn household garbage (especially plastic), cardboard, pressure-treated or painted wood, plywood, or particle board, all of which can release toxic gases.

Renewable also does not mean that all wood is logged in an environmentally sustainable way. "Be sure you are buying from a CT certified forest products harvester, on a job managed by a certified forester if possible," says Steve Broderick, Senior Extension Educator at the Windham County Extension Center. "Then you know the wood is local and that it was cut as part of a forest management operation."

Buying locally reduces road traffic and associated pollution. But more importantly, it decreases the likelihood that diseases and nasty insects will spread. That's a real concern since the Asian Longhorn Beetle was positively identified in Worcester, MA on August 5, 2008. This insect is a serious pest that can kill hardwood trees. It could hitchhike to CT on out-of-state wood from maple, boxelder, alder, birch, elm, horseshoes, poplar or willow trees.

Because of the high price of gas and diesel which fuel chainsaws and trucks, expect the cost of a cord to be higher than it was in 2007. The good news is that a cord of firewood has the same heating potential as about 115-127 gallons of fuel oil, according to John Bartok of Ashford, author of Heating with Wood and Coal. The heating value depends on the type of wood you get (see chart). Hardwood is more dense, and has as much as twice the heat value per cord as softwoods such as pine. Like green wood, softwood can also create more creosote in your chimney.

Keep in mind that firewood from some species like ash burns faster and hotter, and generates more ash waste. Make sure you dispose of ash safely. More than one building has burned to the ground when folks put "cold" ashes in a cardboard box, or threw them on a pile of leaves. Ashes should be stored in a covered steel bucket for at least 4-5 days prior to disposal. Also, don't forget to have your chimney cleaned at least once a year to avoid a potentially devastating house fire.

Finally, the Goodwin Conservation Center recommends that you make sure you get what you pay for. In CT, wood should be sold by the cord, which means when compactly stacked in a pile, it is 4 feet high x 4 feet deep x 8 feet long, or 128 cubic feet. It is illegal to sell firewood by the truckload or "face" cord in CT. Spalding notes that if you buy cut round wood, it does not make a full cord after being split. He has found it is more like 105 cubic feet. "It's all a matter of price vs. volume. All things being equal, you are going to get more wood if you buy cut and split wood, says Broderick." And pass on punky, rotten ant-infested wood.