There’s more to burning wood than you might expect. Whether you’re using an outdoor fire pit, your fireplace, or a wood burning furnace or stove, different woods burn differently from one another.
And maybe you just buy whatever firewood is available at your local store. But have you ever stopped to ask, “What kind of wood is this, anyway? Do certain types of wood give off more heat than others? What type of wood should I be burning?”
The type of firewood available to you often depends on what kind of trees are native to your area. But, given the choice, some types of wood are better at some things than others. We should know — we’ve been through the process of getting a wood burning furnace approved by the EPA, and that involves dozens of burn tests with many different kinds of firewood.
In this guide (and with the help of data from Utah State University), we’ll cover 10 different species of firewood. We’ll tell you how much heat each species puts off, how much a full cord of each species weighs, and more insights to help you find the right wood to burn.
Firewood BTU Chart
The following chart covers basic information on ten species of wood common in North America. Depending on where you live, some species of firewood may be more readily available in your area than others.
| Species | Heat per Cord (Million BTUs) | Weight per Cord (Dry) | Ease of Splitting | Smoke |
| White Oak | 29.1 | 4,200 pounds | Medium | Low |
| Black Locust | 27.9 | 4,020 pounds | Difficult | Low |
| Maple | 25.5 | 3,680 pounds | Easy | Low |
| White Ash | 24.2 | 3,470 pounds | Medium | Low |
| Black Walnut | 22.2 | 3,190 pounds | Easy | Low |
| Elm | 20.9 | 3,020 pounds | Difficult | Medium |
| Birch | 20.8 | 2,990 pounds | Medium | Medium |
| Douglas-fir | 20.7 | 2970 pounds | Easy | High |
| Green Ash | 20 | 2,880 pounds | Easy | Low |
| Sycamore | 19.5 | 2,810 pounds | Difficult | Medium |
The second column indicates how much energy (in British thermal units, or BTUs) a full cord of each species of wood will radiate when burned.
The third column indicates how much a full cord of each species of wood weighs after it’s been fully seasoned and dried out.
The fourth and fifth columns indicate how easy (or difficult) each type of wood is to split and how much smoke each species of wood tends to give off, respectively.
How Much is a Cord of Wood?
A full cord of stacked firewood measures 4 feet high, 8 feet wide, and 4 feet in depth (for a total of 128 cubic feet). A full cord usually contains between 600 and 800 logs.
You may also see the term “face cord” used; this is about ⅓ of a cord, or 4 feet high, 8 feet wide, and 16 inches in depth.
A half cord of wood measures 4 feet high, 8 feet wide, and 2 feet in depth.
How Long Does it Take to Season Firewood?
The best way to season firewood is to stack it on a log rack and let it sit anywhere from 6 months to a year. This allows moisture to evaporate from the logs.
A piece of firewood may contain up to 50% of its weight or more in water. Waterlogged firewood won’t burn well. The goal is to get the moisture content to 20% or less (and you can test the moisture contents of a piece of firewood by using a moisture meter).
Because it takes so long to season firewood properly, most people buy their firewood a year in advance. When seasoning firewood, leave it outdoors in the open at least a few feet away from walls or other obstructions to facilitate proper airflow. Cover the top with a tarp to keep the wood safe from precipitation (but leave the sides uncovered to allow air to circulate).
Is Oak Good Firewood?
One full cord of dry, properly seasoned oak firewood will put off 29.1 million BTUs of energy, making oak one of the most efficient species of wood to burn. Though it’s heavy (with a full, dry cord weighing in at around 4,200 pounds) and not necessarily easy to split, oak wood puts off relatively little smoke when seasoned correctly.
- Heat per cord (in millions of BTUs): 29.1
- Weight per cord (dry): 4,200 pounds
- Ease of splitting: Medium
- Smoke contents: Low
Is Black Locust Good Firewood?
At 27.9 million BTUs of energy per cord, black locust wood is nearly as efficient as oak. It maintains a comparable weight at about 4,000 pounds per cord. It also puts off relatively little smoke, though it is pretty difficult to split if you’re cutting it on your own.
- Heat per cord (in millions of BTUs): 27.9
- Weight per cord (dry): 4,020 pounds
- Ease of splitting: Difficult
- Smoke contents: Low
Is Maple Good Firewood?
Maple is one of only three species of firewood on this list to put off over 25 million BTUs of energy per cord burned. It’s quite a bit lighter than oak or black locust, averaging about 3,700 pounds per cord. It’s also very easy to split, and it puts off very little smoke.
- Heat per cord (in millions of BTUs): 25.5
- Weight per cord (dry): 3,680 pounds
- Ease of splitting: Easy
- Smoke contents: Low
Is White Ash Good Firewood?
White ash is a great middle-of-the-road firewood option in terms of millions of BTUs per cord at 24.2. A dry, seasoned cord of white ash firewood weighs in at around 3,500 pounds, and it produces relatively little smoke. It’s not the easiest type of firewood to split, though, so keep that in mind if you’re cutting your own wood.
- Heat per cord (in millions of BTUs): 24.2
- Weight per cord (dry): 3,470 pounds
- Ease of splitting: Medium
- Smoke contents: Low
Is Black Walnut Good Firewood?
Black walnut is a relatively efficient firewood, offering about 22.2 million BTUs of energy per cord. It’s pretty light for its efficiency, with a full cord clocking in at around 3,200 pounds. It’s also easy to split, and it puts off very little smoke.
- Heat per cord (in millions of BTUs): 22.2
- Weight per cord (dry): 3,190 pounds
- Ease of splitting: Easy
- Smoke contents: Low
Is Elm Good Firewood?
At about 3,000 pounds per cord and with an energy rating of about 20.9 million BTUs per cord, elm is a good middle-of-the-road firewood. Be cautious, though — it’s pretty difficult to split, and it puts off quite a bit more smoke than oak, black locust, maple, white ash, or black walnut.
- Heat per cord (in millions of BTUs): 20.9
- Weight per cord (dry): 3,020 pounds
- Ease of splitting: Difficult
- Smoke contents: Medium
Is Birch Good Firewood?
Birch’s energy capacity is comparable to elm at 20.8 million BTUs per cord. Its weight per cord is also comparable to elm at around 3,000 pounds. Like elm, it puts off a medium amount of smoke, and while it’s not the easiest wood to split on your own, it is easier than elm.
- Heat per cord (in millions of BTUs): 20.8
- Weight per cord (dry): 2,990 pounds
- Ease of splitting: Medium
- Smoke contents: Medium
Is Douglas-Fir Good Firewood?
Douglas-fir firewood is on par with elm and birch in terms of energy efficiency; it puts off about 20.7 million BTUs per cord. It weighs in at about 2,970 pounds per cord and it’s easy to split. The biggest caveat with douglas-fir is that it probably puts out the highest amount of smoke of any firewood on this list.
- Heat per cord (in millions of BTUs): 20.7
- Weight per cord (dry): 2,970 pounds
- Ease of splitting: Easy
- Smoke contents: High
Is Green Ash Good Firewood?
Though every type of firewood on this list is very efficient, green ash does come in second-to-last at just 20 million BTUs per dry, seasoned cord. It is relatively lightweight; at just 2,880 pounds per cord, it’s about 1,300 pounds lighter than oak. It’s also easy to split and emits a low amount of smoke.
- Heat per cord (in millions of BTUs): 20
- Weight per cord (dry): 2,880 pounds
- Ease of splitting: Easy
- Smoke contents: Low
Is Sycamore Good Firewood?
Sycamore has the unfortunate distinction of being the only firewood on this list not to crack 20 million BTUs per cord, just missing the mark at 19.5. It puts off a medium amount of smoke, too, and it’s relatively difficult to split. It is the lightest, though, with a properly seasoned cord of sycamore weighing about 2,800 pounds.
- Heat per cord (in millions of BTUs): 19.5
- Weight per cord (dry): 2,810 pounds
- Ease of splitting: Difficult
- Smoke contents: Medium
What Type of Firewood Should You Get?
As you can see, there’s more to burning wood than you may have expected. Thermal efficiency can vary by millions of BTUs per cord and weight can vary by thousands of pounds. There are also big variations in how easy each species is to split and how much smoke each species emits.
So — which firewood should you get?
In a lot of cases, this simply depends on which wood is native to your area. You may not have many options.
But, if given the choice, oak, black locust, and maple are high on the list in terms of heat per cord. Green ash and sycamore may be less energy efficient, but they’re very lightweight if you plan on hauling the wood yourself.
Whichever type you choose, be sure to store and season your wood properly. That way it will burn efficiently and cleanly, keeping you warm through the fall and winter months.
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