By MATT MAURY

At this time of year, many homeowners have fireplace and woodstove fires burning frequently. There's nothing like getting cozy with a good book in front of a warm fire. And a glowing fire is always welcoming when family and friends visit.

Yet every time a fire is started, we think through those concerns that are often covered in the news - smoke pollution, burn bans, creosote build-up in the chimney, inefficient heat generation, etc. Therefore, I was quite interested when George Mack, a Woodinville chimney sweep, explained how I could eliminate these concerns by building an upside-down fire.

"You put the big logs on the bottom," he told me, "then build with smaller and smaller pieces of firewood until there are small pieces of kindling at the top. It's not a new concept," he continued, "since it originated in Europe hundreds of years ago for the massive tile stoves. With the increasing popularity of wood-burning stoves in the U.S., we are seeing a new interest in building efficient fires."

The art and skill of building a fire is nearly as old as man. We learn from our family, friends or in a scouting experience that you start with some paper, small branches or sticks (kindling) and a match. As the fire begins, we add more and larger pieces of wood. It's the moisture in this new wood that causes the smoke and the gasses to rise from the fire, taking with them the creosote that will condense on the chimney walls and the particulate materials that will escape from the chimney into the environment.

The top-burning fire eliminates these problems. Here's how: As firewood warms, it emits gasses. Since the wood that is warming is below the flame, the gasses are ignited as they rise. So rather than escaping up the chimney and condensing to creosote, the gasses are combusted, thereby increasing the amount of heat generated by the fire.

To build a fire that will last all evening long requires a variety of species of wood. The best bottom layers are of dense hardwoods - oak, maple, etc. The smaller pieces that are crisscrossed above the base layers should be of softer hardwoods, such as alder. All this wood should have air-dried for at least a year to reduce its moisture content, thereby producing a better fire. On top of the logs should be placed kindling - very small branches or, better yet, small pieces of dry cedar. Shakes and shingles, as long as they haven't been painted, stained or treated with preservatives, make excellent kindling. At the top of the pile, place small pieces of newspaper, and then strike a match.

The first thing noticed is that there is virtually no smoke! And there will continue to be little or no smoke until all that's left of the fire is a pile of red-hot embers. It's a very environmentally friendly way to build a fireplace or woodstove fire. b