Vermont Department of Forests, Parks & Recreation
Vermont Agency of Agriculture, Food & Markets
From The Vermont Agency of Agriculture & the Vermont Department of Forests, Parks & Recreation
In response to a larger-than-normal volume of questions and concerns from Vermonters regarding firewood this fall and winter, we reach out to Paul Frederick, a Wood Utilization Forester from The Vermont Department of Forests, Parks & Recreation for some expert firewood advice:
Judging the quality of firewood can be a bit tricky, especially if you’re new to the business. There are a number of ways to describe the moisture content of firewood, and no two dealers seem to use the same ones. Dealers often talk about wood being “dry”, “seasoned”, and “green” which refers to the moisture content of wood, but unfortunately a standard set of definitions has not yet been established by or for the industry. When talking with firewood dealers about their products, always be sure to ask how they define the terms they are using to describe their wood products.
Here are a couple of general guidelines to keep in mind when talking to a potential firewood supplier:
· “Dry wood”… should be an immediately burnable product at the time of delivery. Air drying of split firewood which has been stacked under cover can take as much as a year depending on drying conditions. The moisture content of properly dried firewood should be 25% or less.  Dry wood should never be stored uncovered as it will reabsorb moisture.
· “Kiln dried fire wood”… has been dried through the introduction of heat in a deliberately controlled environment (kiln) – a process that drastically shortens the drying time. As with dry wood, kiln dried firewood should be an immediately burnable product at time of delivery, with a moisture content that should not exceed 25%.
· “Heat-treated wood”… has been heated to achieve a specified internal temperature for a specified period of time in order to kill undesirable organisms (typically, but not always, insects). Heat treating standards are specific to the organism targeted for control. Heat-treated wood is also often kiln dried, but kiln dried wood is not necessarily heat treated and visa-versa.
· “Green wood”… is fresh cut and should not be used for fuel until it has had time to dry properly.
· “Seasoned wood”… is the least well defined of any of the terms associated with firewood. “Seasoning” is synonymous with “drying” but the key to the wood’s actual moisture content is how long and under what conditions the wood has been “seasoned”. When purchasing “seasoned” wood, always be sure to ask your dealer how long the wood has been cut and if it was stacked under cover to facilitate drying. If the wood is stored out in the weather, the moisture content may be closer to that of green wood rather than dry. This is especially true if the wood has been stored in a pile rather than stacked and covered, since it is difficult for air to circulate in the center of a large pile. In general it is best to assume that seasoned wood is not likely to be ready to burn without further drying.
If you are not planning to buy dry wood, the best strategy is to plan ahead and allow plenty of time for your wood to dry under cover. Order wood during the winter or early spring for the following year, stack and cover it to dry during the spring and summer and get it into a shed in the fall. That is the most reliable way to ensure your supply of properly dried firewood.
Understanding this is not a strategy that will work for everyone, here is a list of additional resources to assist folks in the process of judging and purchasing firewood:
· This Wet Wood is a Waste Public Service Announcement (http://www.youtube.com/watch?v=jM2WGgRcnm0) explains how to use a simple moisture meter to test wood to see if it is dry enough to burn. Moisture meters are available in all sizes and can cost as little as $20. Properly dried wood should have a reading of 20% or less.
· This Split, Stack, Cover, Store Public Service Announcement provides instructions on how to dry wood for proper use in wood stoves or fireplaces four easy steps.
1. Split wood to a variety of sizes but no larger than a six-inch wedge
2. Stack wood away from a building and off the ground on a pallet with split side down to promote drying
3. Cover the top of wood with a tarp or woodshed
4. Store wood and allow ample time for the wood to dry. This can be 6-12 months, depending on the type of wood.
 All moisture contents listed here are on a green weight basis.