Wood is a traditional Maine heating source, but there’s still much to learn about it.

Summertime concerns about winter’s heat are pushing supplies of wood, and wood-fired heating sources, to the brink of sustainability. There is discord among government, business and environmental organizations about exactly how much more wood can be safely harvested.

While it seems strange that a state as forested as Maine should be facing a wood shortage, the concerns are quite real. Industry and consumer competition for this resource have caused wood prices to rise and supplies to dwindle.

Report after report extols its virtues or warns of its dangers. The most recent came from the Maine Oil Dealers Association, which hired an air quality specialist to evaluate the particular particulate problems of wood burning.

Of course, this report was sponsored by a less-than-objective group. But the concerns it raised are real: Air quality in Maine would be affected by wholesale increases in wood burning, which echoes the recent statewide debate about outdoor wood-fired boilers.

The state’s wood-to-energy task force, which endorses wider adoption of wood-fired heating sources (especially pellets) also recognizes pollution concerns, as well as a dearth of available information about wood burning in Maine.

Among its draft recommendations is compiling such data through an inventory of structures reliant on wood-fired heat, and tabulation of how much firewood, cord by cord, is used across Maine in a given year, and where.

Of concern, however, is the task force’s recognition of an unsettling unknown: Just how efficient it is to mingle oil and wood heat, a scenario many Mainers are eyeing this winter to reduce costs, while also maintaining comfort.

“Considering how widespread cordwood burning is in Maine, it is surprising that relatively little data on wood burning exists,” the task force’s draft report states. “It is also a concern that very little is known about the oil burners being used so commonly in the state and the interplay between oil and wood heat.”

As prices of oil have increased, wood has become a viable, but scarce, short-term solution for this winter. If per-gallon rates maintain or increase, burning additional wood will be a necessity for many, many Mainers.

Whether wood is a long-term solution, however, is open to debate.

Despite centuries of use, many important questions persist