Burning Ash Dieback Wood (Safety & Seasoning)
Ash affected by dieback can be used as firewood when it is legally sourced, safely processed, and fully seasoned. The disease does not make dry ash automatically unsuitable for a stove, but infected wood may be subject to local movement rules. Split it, stack it with airflow, and confirm 20% moisture or less on a fresh split face before burning.
I have seen a familiar pattern in wood yards: a pile of ash looks dry from the outside, so it goes straight to the stove. Then a moisture-meter reading from the freshly split center tells a different story. With ash dieback in the picture, there is another question before the saw starts: can this wood be moved or processed under local rules?
The safest approach is to treat these as two separate jobs. First, check the tree and the rules. Then process and season the wood, measuring its moisture rather than guessing from bark, color, or time in the stack.
What ash dieback means for firewood
Ash dieback is a disease of ash trees caused by a fungus. It can cause leaf loss, bark lesions, and dead branches, but symptoms alone do not show exactly how stable a tree is. For firewood users, the key issues are tree safety, wood movement rules, and whether the finished fuel is dry enough to burn.
Ash dieback does not, by itself, mean that the wood must never be burned. But local plant-health rules may limit cutting, disposal, or movement of affected material. Rules vary by place and may change, so check with the relevant authority before cutting or transporting it. If instructions are unclear, keep the wood where it is until you get guidance.
Dryness matters for combustion, not just convenience. Wet logs use heat to drive off water, which can reduce useful heat and encourage smoky burning. That is why the most useful readiness test is a moisture reading from a freshly split surface, not a guess based on how long the logs have been stacked.
Assess the tree and prepare safely
A tree with dieback may have dead limbs or weak sections, while other parts may still appear sound. A visual check cannot reliably tell you which limb or stem will fail. Before work, assess the whole situation, including lean, overhead hazards, slope, wind, nearby people, and public access.
I do not treat a dead-looking branch as a predictable one. If a tree is hung up, roadside, overhead, or structurally uncertain, have a qualified arborist assess it. Do not fell or limb a compromised tree alone or without the right skills and equipment. Stop if you cannot tell how it is loaded or where it will fall.
Before using a chainsaw:
- Check the manual for the exact saw’s approved bar lengths, chain setup, fuel, oil, and service limits.
- Inspect the chain brake, chain catcher, throttle lockout, bar, chain tension, and sharpness.
- Use a helmet, eye and hearing protection, chainsaw leg protection, gloves, and suitable boots.
- Keep bystanders outside the work area and plan an escape route before felling.
- Start on stable ground with the brake applied and the bar clear, following the saw’s cold- or warm-start procedure.
- Check that the chain stays still at idle and that oil reaches the chain using the manual’s check procedure.
Chain pitch, gauge, and drive-link count must match the bar and sprocket. A 3/8-inch low-profile chain with a .050-inch gauge is one possible setup, not a standard for every saw. The same goes for depth gauges: .025 inch is common on some chains, but the chain maker’s specification takes priority. Fuel ratios, bar oil, and engine speeds also depend on the model. For example, use 50:1 premix only if the manual specifies it.
Cut and process ash with care
Safe cutting means matching the cut to the wood’s position and load. Look for compression and tension, keep firm footing and a two-handed grip, and do not cut above shoulder height. Avoid the upper quadrant of the guide-bar nose: if it hits an object, the saw can kick back rapidly toward you. A working chain brake and suitable chain help reduce risk, but do not make careless cuts safe.
Do not work on a questionable tree because its wood seems valuable. If you lack the needed competence or equipment, hire a qualified professional. Once rounds are safely on the ground, split them promptly. Smaller pieces expose more surface area to moving air and are easier to dry than large, unsplit rounds.
Keep the chain sharp and cutters even, following the chain maker’s angles and depth-gauge limits. Stop the saw, let hot parts cool, and follow the manual before servicing; disconnect the spark-plug lead when directed. Check chain tension as instructed, and replace damaged or worn parts. Clean the air filter, cooling fins, bar groove, and oil passages. If the saw runs poorly, idles abnormally, or may be running lean, stop and get it checked rather than continuing to cut.
Season ash and verify moisture
Seasoning is the drying process that brings wood to a moisture level suitable for burning. Ash can dry at different rates depending on round size, how it was split, local weather, and stack airflow. There is no reliable calendar shortcut: elapsed time alone does not prove a log is ready.
Stack the split wood on a raised, stable base. Leave space for air to pass through the pile, cover the top to shed rain, and keep the sides open. Keep the stack stable and away from buildings or ignition sources as local fire rules require. Store seasoned wood off the ground under the same top-cover and airflow conditions.
A moisture meter is useful only when used on the right surface. Split a representative piece and test the fresh inner face, not the weathered exterior. Follow the meter’s instructions for probe placement and settings. Check more than one piece from the stack, especially thicker splits, because the outside can dry before the center.
| What you check | Useful method | What the result tells you |
|---|---|---|
| Moisture | Read a freshly split face with a suitable meter | Aim for 20% or less before burning |
| Stack airflow | Raise the pile and leave sides open | Helps moisture escape |
| Rain protection | Cover the top, not the whole stack | Limits rain exposure without sealing in moisture |
| Drying time | Recheck wood rather than relying on a date | Readiness depends on size, split, climate, and stacking |
If readings are above 20%, leave the wood to dry and test again. Do not burn green ash on the assumption that it has seasoned long enough. Once dry, store it where it stays dry and ventilated, and burn it only in an appliance or site where burning is allowed. Follow the appliance instructions and local smoke rules. Do not burn painted, treated, contaminated, or otherwise unsuitable wood.
Practical yard scenarios
These are common working situations, not controlled trials. They show how to apply the same safety and moisture checks to different ash piles. In each case, confirm local movement rules before moving wood, and do not treat disease symptoms as a measure of tree stability.
A standing tree with dead limbs
A dead crown or hanging branch changes the risk before the first cut. A homeowner who cannot assess the tree’s stability or control its fall should call a qualified arborist. Do not fell it alone or assume that a calm day makes brittle or compromised limbs predictable.
Large rounds from a felled tree
Large rounds can remain wet at the center even after their surfaces look dry. Split them into manageable pieces, stack them off the ground with open sides, and test the inner face after further drying. A low reading on one thin split does not confirm that the whole pile is ready.
A pile already stacked for winter
Do not decide readiness by season or appearance alone. Select several representative logs, split them, and measure the fresh faces. If a reading is over 20%, return the wood to a ventilated stack. Keep potentially affected ash within any local movement limits while it dries.
Storage and seasonal care
Storage protects both the seasoned firewood and the equipment used to process it. Keep the pile stable, off the ground, and covered on top with open sides for airflow. Follow local fire rules for where to place it, and keep the public away from unstable stacks.
For a chainsaw, follow the manual for fuel storage or draining, bar and chain cleaning, corrosion protection, and battery care if it is a battery model. Store fuel in approved containers and obey local hazardous-material rules. Do not move potentially affected ash outside locally permitted boundaries. If the rules are uncertain, contact the plant-health authority before transport or disposal.
FAQ
Can I burn ash wood from a tree with ash dieback?
Usually, the wood can be burned if it is dry, suitable for the appliance, and burning is permitted locally. Check plant-health rules before cutting or moving it, since requirements vary by location.
Is ash dieback wood dangerous to burn?
Ash dieback alone is not a reason to assume dry wood is unsuitable. Burn only properly seasoned wood in an allowed appliance, and avoid wood that is painted, treated, contaminated, or otherwise unsuitable.
Does ash dieback wood need to be burned where it fell?
Not everywhere. Movement rules depend on local plant-health guidance. Check with the relevant authority before transporting affected ash, and follow its instructions for disposal.
How dry should ash firewood be?
Aim for 20% moisture or less. Measure the freshly split inner face with a suitable meter, because the outside of a log may be drier than its center.
How long does ash take to season?
There is no single dependable drying time. Log size, splitting, weather, and stack airflow all affect drying, so use moisture readings rather than a calendar date.
Can I check moisture on the bark or outside of a log?
That reading may not show the moisture in the center. Split a representative log and test the fresh face, following the meter’s instructions.
Should I cover an ash woodpile?
Cover the top to keep rain off, while leaving the sides open for airflow. Raise the stack above the ground and keep it stable.
Is a diseased ash tree safe to fell?
Not necessarily. Dieback symptoms do not show which parts are structurally sound. Have a qualified arborist assess hazardous, hung-up, roadside, or overhead-risk trees.
Can I use any chainsaw chain for cutting ash?
No. Chain pitch, gauge, and drive-link count must match the saw’s bar and sprocket. Check the saw and chain manuals rather than relying on a common setup.
What should I do if the moisture reading is over 20%?
Keep seasoning the wood in a raised, ventilated stack with rain protection over the top. Test again on a fresh split face before burning.
(This article was written by one of our staff writers, Samuel Vance. Visit our Meet the Team page.)
