What Is the BTU Value of Tree of Heaven? (Heat Output Guide)

Seasoned tree-of-heaven firewood is commonly estimated at about 14–16 million BTU per full cord, but that is a planning range, not a guarantee. A cord is 128 cubic feet of stacked wood, including air spaces. Moisture, how the wood is stacked, and how well your appliance burns it all affect the heat you actually get.

A steady fire is one of the comforts a wood stove or fireplace can provide. But when a manual, seller, or firewood chart gives a BTU figure, it can be hard to tell what that number means for the wood you have. The key is to separate the wood’s estimated energy from the heat your home will receive.

I start with three questions: Is the wood dry? Is the amount truly a full cord? And is the appliance designed and maintained to burn cordwood? Those answers matter as much as the tree species.

Tree-of-Heaven BTU Value, Moisture Basis, and Cord Comparisons

Tree of heaven, or Ailanthus altissima, is a relatively low-density hardwood with a commonly cited firewood estimate of about 14–16 million BTU per full cord when seasoned. Treat that range as an estimate, not a fixed rating. Moisture, log size, stacking, and appliance performance all affect useful heat.

BTU means British thermal unit, a measure of heat energy. A firewood BTU value estimates the energy in the wood, but it does not promise that all of that energy will warm a room. Some heat leaves through the flue, and damp fuel uses energy to evaporate water.

A full cord is a stack measuring 4 feet high, 4 feet deep, and 8 feet long: 128 cubic feet, including the gaps between pieces. A “face cord” has no fixed volume unless the seller gives the stack’s height, length, and piece length. So a BTU-per-cord estimate cannot be applied fairly to an unspecified pile.

The per-pound estimate is based on oven-dry wood. Firewood burned in a home is rarely oven-dry, and the appliance does not turn every BTU into useful room heat. That is why cord estimates and actual heating results can differ.

Tree of heaven generally provides less heat per cord than denser oak, because a cord of lower-density wood contains less wood mass. This does not mean every cord of tree of heaven performs the same. A loosely stacked pile may contain less wood than a tightly stacked one, and a wet cord will give less useful heat than a dry one.

Takeaway: Use 14–16 million BTU per full cord as a rough estimate. Check the actual volume and dryness before comparing a seller’s price or a heating claim.

Worked Firewood-Planning Scenarios

These examples show how to use the published range without treating it as an exact promise. They are planning scenarios, not reports of measured home installations. In each case, the estimated energy changes with the amount of wood, while the heat delivered also depends on moisture and the appliance.

Scenario 1: A measured half cord. If the stack is genuinely half of a full cord and is similarly seasoned, a simple estimate is 7–8 million BTU in the wood. This is a volume-based calculation: half of the 14–16 million BTU full-cord range. It does not predict how warm a particular room will get.

Scenario 2: A pile called a face cord. The name alone is not enough to calculate BTUs. If the stack is 4 feet high and 8 feet long but the pieces are 16 inches long, its nominal stacked volume is about 85 cubic feet, not 128. That is roughly two-thirds of a full cord by volume, before accounting for differences in stacking and wood size. Ask for dimensions rather than assuming every face cord is alike.

Scenario 3: A cord that still feels damp. A full cord may meet the volume standard and still burn poorly if it has not dried enough. Moisture uses energy as the wood heats, can reduce useful heat, and can increase smoke and creosote deposits. Measure a freshly split face with a moisture meter; do not judge dryness by the calendar alone.

Scenario 4: Comparing tree of heaven with oak. Compare the same measured volume at similar moisture levels, and remember that a cord of denser oak generally contains more wood mass. A higher heat figure for oak does not prove that a seller’s pile is larger or drier. Ask how the volume was measured and how moisture was checked.

These comparisons are most useful when buying or planning a wood supply. They do not replace the appliance manual, which gives the approved fuel and operating instructions for your stove or fireplace.

Safe Cutting, Splitting, and Firewood-Processing Setup

Processing tree-of-heaven wood safely starts before the saw is running. Check the tree, the work area, the saw’s manual, and local rules for handling or disposal. A BTU rating says nothing about whether a tree is safe to fell or whether a chainsaw setup is suitable for the job.

Wear chainsaw personal protective equipment (PPE) specified for the work, and inspect the tree for lean, overhead hazards, nearby buildings, and clear escape routes. Keep bystanders away from the cutting area. If the trunk is hung up, under tension, heavily leaning, or close to a target, stop and contact a qualified tree worker.

A suspended or strongly leaning trunk can split along its length during cutting. This dangerous failure is called a barber-chair because the trunk can open and move suddenly. It can cause fatal injury. Do not make an uncontrolled felling or bucking cut to free a hung-up tree.

For a tree that is safe to process:

• Use a sharp, correctly tensioned chain and a saw setup approved by the manufacturer. Check the manual for bar, chain, fuel, and operating limits.
• Buck the trunk into lengths that suit your appliance, then split the rounds promptly. Keep people clear of the cutting zone.
• Do not cut above shoulder height. Do not force a dull chain through wood; it takes more effort and raises the risk of losing control.
• Check local rules before moving or disposing of tree-of-heaven material. Requirements can differ by location.

BTU content is a property of the firewood, not a chainsaw-fit specification. The saw manual is the source for safe equipment limits; the appliance manual is the source for acceptable fuel and operation.

Takeaway: If the tree is under tension, hung up, or near people or structures, leave the cut to a qualified professional. Safe processing comes before heat estimates.

Seasoning, Moisture Testing, and Burning Performance

Seasoning is the process of drying split firewood so it burns more effectively. A common target is 20% moisture or less, checked on a newly split face with a moisture meter. A woodpile’s age alone cannot confirm that it is ready, because drying depends on the wood and how it is stored.

Split wood promptly and stack it off the ground, with space for air to move around the pieces. Cover the top to shed rain or snow, but leave the sides open so moisture can escape. A tarp wrapped tightly around the stack can limit airflow and slow drying.

To check moisture, split a piece and press the meter’s pins into the fresh inner face, following the meter’s instructions. The outside of a log may be drier than its center, so a surface reading can be misleading. Test more than one piece if the stack seems uneven.

Wood above the 20% target may still light, but it is less effective fuel. Some of the fire’s energy goes toward heating and driving off water. Wetter wood can also produce more smoke and creosote, a deposit that can build up in a chimney or flue. Follow your appliance instructions and arrange regular inspection and cleaning as directed.

Burn only dry wood in an appliance approved for cordwood. Keep air controls and the flue system in the condition and configuration required by the manufacturer. A species’ BTU estimate cannot make an appliance safe to use with fuel it does not approve.

Takeaway: Split, stack with airflow, and test the fresh interior. Use the meter reading, not a guessed seasoning period, to decide whether the wood is ready.

Chainsaw Maintenance and Seasonal Firewood Storage

A well-kept saw helps you process firewood with better control, while a well-stored woodpile helps keep seasoned fuel dry. These jobs affect how safely you prepare and use tree-of-heaven firewood, but they do not change the species’ estimated BTU content.

Before cutting, follow the saw manual for chain tension, sharpening, bar and chain fit, fuel, and other checks. Stop if the chain is dull, damaged, or not tensioned as directed. Never try to make a poorly maintained saw compensate for difficult cuts by pushing harder.

For storage, keep the stack stable and raised off the ground. Cover its top against precipitation while leaving the sides open to airflow. Store firewood as your local rules and appliance guidance allow, and recheck moisture before burning, especially after long or wet storage.

When comparing firewood offers, use the same basis: measured stacked volume and similar moisture. Ask whether the quoted amount is a full cord or a stated smaller stack, and request the dimensions. A pile’s label alone does not establish its volume or heat value.

Takeaway: Maintain the saw by its manual, protect the woodpile from ground moisture and rain, and measure both volume and moisture instead of relying on labels.

Conclusion and Frequently Asked Questions

Tree of heaven is commonly estimated at 14–16 million BTU per full cord of seasoned wood, but that range is only a starting point. A true cord measures 128 stacked cubic feet, and wood at 20% moisture or less is a useful target for effective burning. Dryness, stacking, and appliance performance determine how much heat you actually get.

Is tree of heaven good firewood?
It can be used as firewood if it is properly seasoned and your appliance approves cordwood. Its lower density means a cord generally provides less heat than a cord of dense oak.

How many BTUs are in a cord of tree of heaven?
A commonly published estimate is about 14–16 million BTU per full cord. Treat it as an approximate range, not a guaranteed value.

What counts as a full cord?
A full cord is 128 cubic feet of stacked firewood, including air spaces. A typical stack is 4 feet by 4 feet by 8 feet.

How many BTUs are in a face cord?
There is no single answer because a face cord is not a standard volume. You need the stack’s height, length, and piece length to estimate its volume.

How dry should tree-of-heaven firewood be?
Aim for 20% moisture or less. Measure a freshly split face with a moisture meter; the outside of a log may be drier than its center.

Does wet tree of heaven produce less useful heat?
Yes. Water in the wood uses energy as it heats and evaporates, leaving less heat available for the room. Wet wood can also produce more smoke and creosote.

Is tree of heaven hotter than oak?
A cord of tree of heaven generally provides less heat than a cord of dense oak. Compare the same measured volume at similar moisture levels for a fair comparison.

How can I tell if a seller’s cord is a full cord?
Ask for the stack dimensions. A full cord totals 128 cubic feet of stacked wood; the term “face cord” alone does not specify a standard amount.

Can I burn tree of heaven in any wood stove?
No. Use it only in an appliance approved for cordwood, and follow that appliance’s manual for fuel and operation.

Is it safe to cut a leaning or hung-up tree myself?
Not necessarily. A trunk under tension or suspended above the ground can split suddenly in a barber-chair. Stop and contact a qualified tree worker when a tree is hung up, under tension, or near targets.

(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)