Firewood sanitization technologies

There are options for firewood sanitization that allow campers and others to purchase firewood wherever they choose, while still preventing the spread of tag-along insects.

Example of a firewood kiln. Long green structure with metal siding, three individuals standing in front of the door in the front of the structure.
A MiniQuick Firewood kiln with a 6-cord capacity. Kilns not only reduce drying time but also meet sterilizing temperature requirements for certification (and to prevent spreading invasive species). Photo Credit: Emilia McConnell

Firewood movement is widely recognized as one of the primary pathways for spreading wood-infesting invasive insects and pests. It is well established that the rapid and uncontrollable spread of the emerald ash borer (EAB) across Michigan and the eastern United States was largely connected to the movement of firewood from infested zones to campgrounds creating new infestation zones. These pests can devastate Michigan’s forests.

While an ideal solution to this problem is to buy local firewood, Michigan State University (MSU) Extension recognizes this is a difficult behavior to enforce and is sometimes not possible or available. There are options, though, that allow campers and others to purchase firewood wherever they choose, while still preventing the spread of tag-along insects. If you are a producer, consider integrating these technologies into your business.

Kiln-dried wood has two clear benefits. First, the moisture content is typically 15-20%, without waiting 2-3 years for full seasoning. This means firewood burns cleaner and more efficiently, with a higher heating value (more BTUs by volume) because less energy is consumed evaporating the moisture that would otherwise be present. Second, the process eliminates unwanted insects and diseases from spreading around the state.

Kilns typically bake wood for 1-3 days at 120 – 220 F. The temperature required for certified heat-treatment varies by state, but ranges from 140 (60 C) to 160 (71 C) F for 24 hours. The American Firewood Producers and Distributors Association (AFPDA) has a certification program for sanitation of wood products above the current level required by the International Standards of Phytosanitary Measures. Clients of AFPDA, including big box retailers like Lowe’s, Menards, and Home Depot, will now play a critical role in preventing the spread of pests and diseases through firewood.

Kilns used for drying firewood are typically modified lumber kilns or installed in insulated containers/van-bodies. In 2009, a company developed a kiln specific to the firewood industry called the Quick firewood kiln, which is similar to the insulated container concept. Since then, other manufacturers have entered this market, such as Nova Dry Kilns, which offer hot water heat systems that can utilize wood waste as an energy source, forced air exhaust, and steady chamber temperatures for reduced warpage. The use of waste wood (like residuals including limbs and bark) can help cut costs and make heat-treating more cost-effective.

Remember that although kiln dried or heat-treated firewood can cost more than air-seasoned firewood, there are two important benefits: drastically reduced risk of spreading pests and diseases, and a significantly reduced moisture content for cleaner burning and better heat.

Reference to commercial products or trade names does not imply endorsement by Michigan State University Extension or bias against those not mentioned. Information presented here does not supersede the product directions.

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