Freshly chopped firewood has up to 50% water content and won’t burn in your fireplace. First, you must let the firewood season (dry), which allows the moisture to escape––the drier the wood, the cleaner the burn. When the wood gets down below 20% water content, it’s ready to burn. Burning unseasoned (green) or even partially seasoned wood in your stove or fireplace will cause creosote build-up in your chimney, which can lead to a chimney fire at the worst, and a lack of fire or a roomful or smoke at best. Every homeowner reliant on wood should know how to season wood.
Surface water will usually evaporate quickly; the concern is the moisture content within the wood.
Wood such as shagbark hickory, cherry and black locust will gain little benefit from air drying, as they have low moisture content. On the other hand, wood from such trees as hemlock, cottonwood, American elm and sycamore will benefit from long drying times. Many other tree types are variable.
Importantly, there isn’t any point seasoning wood longer than it needs to be. Over-dried wood will have less energy as volatile esters in the wood evaporate. These waxy substances contain a great deal of heat energy, so it is a mistake to think that longer is necessarily better.
A special instrument can be hired or purchased that tests the moisture content of wood (usually known as a “wood moisture test meter” or similar).
Before drying, know the properties of your wood.
The duration of seasoning depends on the wood and for deciduous trees, when the tree was felled. The sap of deciduous trees moves to the roots in the winter, so such trees felled in winter have a much lower moisture content to begin with, and so will be seasoned more quickly. In general, pine and other softwoods require around 6 to 12 months to season, while hardwoods such as oak require a year to 2 years. However, this rule of thumb has exceptions, so knowing the tree type and its water content is important.
- If you don’t have or don’t want to make side supports, you can stack the ends by turning the direction of wood 90 degrees with each layer and the end stacks will be self supporting.
Ensure that the top of the wood is covered to allow rain (or snow) to run off without soaking the wood.
However, keep the ends of the stack uncovered to allow air to circulate and moisture to escape.
- Bark acts like a lid on firewood, offering natural protection. On split wood, stack the wood with the bark on the bottom to allow the wood to dry faster. If you are storing the wood without cover, stacking with the bark on top will prevent some of the rain from soaking into the wood.
- There are two theories on the covering of wood during the seasoning process and you must decide for yourself which theory you wish to follow. One theory is that already stated––cover the wood to prevent the rain and snow from entering the center of the stack and gathering there. However, within the firewood community, another theory holds that you do not have to cover your wood at all, ever. Just leave it out there in the weather and it will season just as well as if you covered it. This theory has its supporters and the they are quite sure it works just as well as covering your pile. Perhaps divide your wood and try an experiment with both ways.
Check for wood dryness.
You can use the wood moisture test meter as mentioned earlier, if you have access to one. Alternatively, try these simple test:
- 1. Pick two pieces of wood that you think is dry. Knock the two pieces together. If you hear more of a “ring” than a “thud”, then it’s probably dry.
- 2. Also, check for radial cracks at the ends of the wood, which indicate dryness.
- 3. Burn a piece on a roaring fire base. If three of the sides begin to burn within 15 minutes, the fuel is dry.
Tips and Old Wives’ Tales!
- The notion that pine is dangerous to burn, or creates more creosote is an old wives’ tale. If seasoned properly, it will not create any more creosote than other types of wood. It does, however, burn hotter and faster than denser hardwoods due to its high resin content, meaning that you’ll churn through it faster.
- Place the stack of wood where it will get the most sun all day long.
- Ash cannot be burned immediately as most people seem to think. It needs to be seasoned like any other wood. Most people think ash can be burned immediately because it has a lower moisture content than any other fresh cut woods. Ash can have as little as 30% moisture content compared to 50% of other species of wood. Most wood is seasoned enough after 8 months if proper steps are taken, but longer is better obviously. Ideally you want only 20% moisture content in your wood
- Keep it covered so it doesn’t get wet from rain/snow.
- Wood should not be stored closer than twenty feet (6 meters) away from your home. In addition, the ground should be prepared with anti termite protection and should be treated regularly to prevent termites and carpenter ants from forming a home in your woodpile.
- Never stack rotten wood––there is no point keeping it as it will provide very little heat when burned.
- Do not stack wood higher than your own height. Being hit on the head by a log falling can cause serious injury.
- Never completely cover the wood with a tarp. It will serve to trap the moisture that is escaping from the wood and will rot the wood rather than dry it. The moisture must be allowed to escape the pile.
- Be careful chopping wood. It’s easier than you think to injure yourself with that axe. (Actually, accidents with axes are one of the leading causes of injuries in homes where homeowners provide their own wood.)
- Some woods naturally spit a lot, even after seasoning. Take additional care with such woods to avoid dry materials and fabrics from catching on fire due to sparks by getting a fully fitting sparkguard. And get ready to sacrifice a rug a season to the ones that get past you!
- Do not burn unseasoned (green) or even partially seasoned wood in your stove or fireplace as this will cause creosote build-up in your chimney, which could lead to a chimney fire. Moreover, it may not even burn at all.
- When chopping wood, wear goggles and baseball catcher’s shin guards to protect yourself from the axe entering your shins on a missed swing.
- Avoid using endangered species of trees for wood, as well as avoiding any native species that are on the decline.
- Be wary of snakes, spiders and/or other potentially dangerous creatures taking up residence in your woodpile. Never put your hand into a pile unprotected––purchase decent leather or other gloves and move wood from the edges rather than sticking hands into holes.
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