The Cooperative Extension at the University of Nebraska Lincoln offers an online version of their brochure titled Heating With Wood. The easy-to-find introductory synopsis assured us we were in the right place: Heat content, burning characteristics and overall quality of woods commonly burned in Nebraska, as well as information on buying firewood, are included here.
First, we learned the important distinction between green and dry wood. Freshly cut green wood may contain as much as 50% water by weight. Since heat is lost as the water is burned off, green wood produces less heat than air-dried or seasoned wood, and it releases more smoke and creosote in the process.
Density, or dry weight per volume, is a key factor in choosing good firewood. Heavier hardwoods, from broadleafed trees, produce more heat than softer, lighter conifers. Dense woods such as oak, ash, or mulberry are recommended; cottonwood, an abundant broadleafed tree in many regions, is, nevertheless, a low-density hardwood, and therefore, a poor heat source.
A table of "Firewood Facts" lists wood species from apple (excellent) to willow (poor) for weight, dryness, heat per cord in BTUs, ease of splitting, smoke, sparks, coals, and fragrance.
Never content with just one resource, we headed out to see if we could find more firewood factoids. This time we experimented with a haphazard search strategy that occasionally works very well. We typed the URL www.woodheat.org into the location or address field of our browser, without actually knowing if the domain existed or if it would be pertinent.
Luck was with us. We discovered a resource "in support of responsible home heating with wood." The firewood page confirmed and expanded upon what we'd already learned. The energy content of wood varies according to density. Maple and oak are traditionally favored fuels in central North America, but since these trees are highly valued for other uses, the authors recommend using woods that are abundant and affordable in your area. Rock elm topped their list of hottest woods, and balsam fir checked in with the fewest BTUs.
Both sites emphasize the importance of using well-dried wood, cut to the correct size and stored properly. Stay warm and safe, and don't let the rising price of heating oil give you chills this winter.
Wood fuel is wood used as fuel. The burning of wood is currently the largest use of energy derived from a solid fuel biomass. Wood fuel can be used for cooking and heating, and occasionally for fueling steam engines and steam turbines that generate electricity. Wood fuel may be available as firewood (eg. logs, bolts, blocks), charcoal, chips, sheets, pellets and sawdust. The particular form used depends upon factors such as source, quantity, quality and application. Sawmill waste and construction industry by-products also include various forms of lumber tailings.
