A cord of wood is not a fixed amount of heat. It is a fixed amount of space — 128 cubic feet, stacked — and the heat inside that space depends entirely on the species, how dry the wood is, and how efficiently you burn it. A cord of hickory carries roughly twice the heat of a cord of aspen. Green wood carries about half the heat of seasoned wood, and the difference is water you have to boil off before you get any warmth.
This page has the numbers, the sources, and the method. Heat content by species comes from Utah State University Extension's firewood table, with independent readings from Illinois, South Dakota State, Penn State, and Iowa State. Tree-to-cord yield comes from University of Wisconsin–Madison Extension. Where the sources disagree, the disagreement is shown rather than hidden — because if you are pricing firewood, the spread matters more than the average.
Estimate your own tree
Measure the trunk diameter 4.5 feet above the ground, estimate the height, and pick the species. Then adjust the moisture and the fuel prices to match your own situation.
What a cord actually is
A full cord is 128 cubic feet of wood and air, stacked 4 feet high, 4 feet deep, and 8 feet long. The Michigan Department of Natural Resources defines it exactly that way: “A standard cord is 8 feet long, 4 feet wide and 4 feet high… defined as 128 cubic feet when the wood is neatly stacked.”
The 128 cubic feet includes the air between the pieces. A standard hardwood cord holds about 80 cubic feet of solid wood — roughly 62% of the stack. The rest is space, and a stack built with big, loose pieces holds less wood than one built tight.
A face cord, also called a rick, is the same 4-by-8-foot face but only one split-length deep. Its volume depends entirely on how long the splits are. At 16-inch splits, a face cord is exactly one third of a full cord. A seller quoting “a cord” of 16-inch wood stacked one row deep is offering a third of what the word is supposed to mean.
To convert any stack: cords = height (ft) × width (ft) × stick length (ft) ÷ 128.
Heat content by species
Million BTU per full cord, air-dried wood at roughly 20% moisture content. “Dry weight” is the air-dried weight of one full cord; “green weight” is the weight of the same cord freshly cut, before it has dried.
| Species | MMBtu per cord | Dry lb per cord | Green lb per cord |
|---|---|---|---|
| Osage orange | 32.9 | 4,728 | 5,120 |
| White oak | 29.1 | 4,200 | 5,573 |
| Shagbark hickory | 28.6 | 4,072 | — |
| Black locust | 27.9 | 4,016 | 4,616 |
| Honeylocust | 26.7 | 3,832 | 4,640 |
| Bur oak | 26.2 | 3,768 | 4,960 |
| Hard / sugar maple | 25.5 | 3,680 | 4,685 |
| Red oak | 24.6 | 3,528 | 4,888 |
| Yellow birch | 23.6 | 2,992 | 4,312 |
| Black walnut | 22.2 | 3,192 | 4,584 |
| Black cherry | 20.4 | 2,928 | 3,696 |
| American elm | 20.0 | 2,872 | 4,456 |
| Green ash | 20.0 | 2,880 | 4,184 |
| Sycamore | 19.5 | 2,808 | 5,096 |
| Silver maple | 19.0 | 2,752 | 3,904 |
| Red maple | 18.7 | 2,752 | 3,904 |
| Quaking aspen | 18.2 | 2,160 | — |
| White pine | 15.9 | 2,250 | — |
| Cottonwood | 15.8 | 2,272 | 4,640 |
| Spruce | 15.5 | 2,240 | 2,800 |
| Basswood | 13.8 | 1,984 | 4,404 |
| Eastern redcedar | 13.0 | 2,060 | — |
Where the sources disagree
The table above uses the Utah State University Extension values where available, because it is the only source that pairs heat content with both dry and green weight for the same species. Other university extension tables were used to check it, and they do not always agree:
- Quaking aspen: 18.2 (Utah State) versus 14 (South Dakota State) — a 30% spread, the widest of any common species.
- Eastern redcedar: 13.0 (Utah State) versus 21 (South Dakota State, for redcedar and Rocky Mountain juniper combined — a figure covering two very different woods).
- Green ash: 20.0 (Utah State) and 20 (South Dakota State) versus 23.0 (Illinois Extension).
- White and bur oak: 29.1 for white oak and 26.2 for bur oak (Utah State), 26.5 for white and bur combined (Illinois), 25 for bur oak (South Dakota State), 25.7 for the white oak group (Penn State).
- Sugar and hard maple: 25.5 (Utah State), 24.0 (South Dakota State), 24.0 (Penn State), 23.7 (Illinois).
Species where the sources agree tightly, and where the numbers are safe to rely on: black walnut (22.0–22.3), silver maple (19.0–19.5), black locust (27.9–28.1), basswood (13–13.8), spruce (15.5–16), and white birch (20.3–21). Dry weights cross-check almost perfectly where two sources list the same species: basswood, silver maple, and cottonwood match exactly between Utah State and Iowa State, and red oak is within eight pounds.
The spread is the point. A cord of aspen can be worth 18 MMBtu or 14 MMBtu depending on which published table you trust. Anyone selling you firewood is quoting you one of these tables without saying which, and you should know the answer before you agree on a price.
How much firewood is in a tree
University of Wisconsin–Madison Extension publishes a cord-volume table by tree height and diameter at breast height (MF-773, Managing Your Woodland for Firewood). Selected rows:
| Tree height (ft) | 14 in DBH | 16 in | 18 in | 20 in | 22 in | 24 in |
|---|---|---|---|---|---|---|
| 30 | .22 | — | — | — | — | — |
| 40 | .29 | .38 | .47 | .58 | .69 | .81 |
| 50 | .36 | .46 | .58 | .71 | .85 | 1.00 |
| 60 | .43 | .55 | .69 | .84 | 1.01 | 1.20 |
| 70 | .50 | .64 | .80 | .98 | 1.17 | 1.38 |
Diameter at breast height is measured outside the bark at 4.5 feet above the ground. Other published estimates land in the same neighborhood but not on the same number: Cornell University's table, built on the Forest Service's NED-2 software, gives 0.73 cords for a 20-inch tree regardless of height; the Ohio State tree scale stick says a 20-inch, 60-foot tree holds about 0.630 cords; and Nebraska's firewood guide puts one full cord at a 22-inch DBH.
Reasonable range for a 20-inch, 50-foot tree: 0.6 to 0.8 full cords. The calculator uses the Wisconsin figure and publishes the range with it.
Moisture is the biggest number in firewood
A cord of seasoned white oak holds 29.1 million BTU. The same cord, green, holds about 14.6 million. Nothing changed about the tree — half the difference went into the sky as steam.
The physics is simple. One pound of oven-dry hardwood holds about 8,600 Btu (Missouri Extension, G5450). Water in the wood has to be boiled off before you get any heat, and that takes about 970 Btu per pound of water (USDA Forest Service, AH-188, Chapter 11). So the heat actually available falls as moisture climbs:
| Moisture content | Heat multiplier | What it looks like |
|---|---|---|
| 10% | 1.150 | kiln-dried or very well seasoned |
| 15% | 1.076 | excellent stove wood |
| 20% | 1.000 | the baseline for the table above; the EPA's target |
| 30% | 0.844 | damp, smoky, poor draft |
| 40% | 0.680 | partly seasoned |
| 50% | 0.502 | green, straight from the tree |
The EPA's Burn Wise guidance is to burn wood under 20% moisture. Burning wet wood does not just waste heat — it deposits creosote in the flue, and creosote buildup is a leading cause of residential chimney fires.
The only way to know your wood's moisture content is a $20 moisture meter, read on a freshly split face. Not on the weathered outside of a log. Not by eyeballing it. A meter.
Worked example
A 24-inch DBH white oak, 50 feet tall, cut green, burned in a modern 72%-efficient wood stove, compared against a home heating with propane at $2.64 a gallon.
| Green wood (50% MC) | Seasoned wood (20% MC) | |
|---|---|---|
| Full cords of firewood | 1.00 | 1.00 |
| Face cords at 16-inch splits | 0.33 | 0.33 |
| Weight, freshly cut | 5,573 lb | 5,573 lb |
| Weight, once seasoned | 4,200 lb | 4,200 lb |
| Gross heat | 14.6 MMBtu | 29.1 MMBtu |
| Heat delivered to the house | 10.5 MMBtu | 21.0 MMBtu |
| Propane to replace it | 143.9 gal | 286.8 gal |
| Value at $2.64/gal | $380 | $757 |
| CO2 avoided | 1,822 lb (0.91 tons) | 3,631 lb (1.82 tons) |
Two things stand out. The same tree is worth twice as much seasoned as it is green — which means a year of drying is worth roughly $375 on a single tree, and that is before you account for the fact that wet wood is harder to burn and makes more mess. And the tree is worth something real in either case: a cord and a half of wood from one yard tree is not nothing against a fuel bill.
A second tree, for comparison
A 20-inch DBH red oak at 40 feet, green, same stove and same propane price: 0.58 full cords, 7.2 MMBtu gross, 5.2 MMBtu delivered, 70.5 gallons of propane, $186, and 893 lb of CO2 avoided. Species is worth about 18% on the same-size tree.
Frequently asked questions
Is a cord the same as a rick?
No. A full cord is 128 cubic feet. A face cord, or rick, is the same 4-by-8-foot face one split-length deep, so its volume depends on how long the splits are. At 16-inch splits it is exactly one third of a full cord.
How many cords should I buy for a winter?
One full cord of seasoned dense hardwood burns about 2,500–3,000 lb, so roughly 4–5 cords covers a typical Midwestern home for a heating season, and considerably more for a large or drafty house. Michigan State University Extension recommends cutting and stacking green wood in the spring for the following winter, which gives it the 6–12 months it needs to get under 20% moisture.
Does firewood have to be certified in Michigan?
Starting January 1, 2027, only heat-treated and certified firewood may be brought into Michigan. The certification standard is a minimum core temperature of 140 °F for at least 60 minutes. Kiln-dried dimensional lumber and wood chips no larger than one inch in two dimensions are exempt, as is material going directly to a mill or kiln for processing. Wood cut and burned locally is not affected by the quarantine, and MDARD recommends buying firewood within 10 miles of where you plan to burn it. From January 1, 2028, violators get a warning letter first, then fines of $1,000 to $10,000.
Is the wood from my tree removal actually worth anything?
Sometimes, and the calculator will tell you. The wood is worth the heat in it, priced against what you would pay for the same heat from your current fuel. Keep in mind that fresh-cut wood is green and worth about half what the same wood is worth once seasoned, and that you still have to split, stack, and haul it.
Why do the published tables disagree?
Because they were built from different samples, different species groupings, and different moisture assumptions. Some group species together; some measure air-dried weight and others measure green weight. The disagreement is largest for low-density woods like aspen and cedar. Where this page gives a single number, it uses the source that carries the most complete data, and it shows the competing readings next to it.
Is this a timber appraisal?
No. A logger pays for logs, not firewood, and yard trees are usually worth nothing as timber because of embedded metal and poor lumber quality. This is a firewood energy estimate, and it is the number that decides whether keeping the wood is worth more than paying a disposal fee.
Sources
- Species heat content and weights: Utah State University Extension, Wood Heating — https://extension.usu.edu/forestry/resources/forest-products/wood-heating, checked against Illinois Extension (extension.illinois.edu/firewood/burning-safety), South Dakota State University Extension (extension.sdstate.edu/choosing-firewood), Penn State Extension (extension.psu.edu/heating-with-wood-an-introduction), and Iowa State University Extension (naturalresources.extension.iastate.edu/forestry/forest_products/fuel.html).
- Tree-to-cord yield: University of Wisconsin–Madison Extension, MF-773 Managing Your Woodland for Firewood — forestry.extension.wisc.edu/files/2017/09/MF-773.pdf, checked against Cornell University (blogs.cornell.edu/dist/5769/files/2022/10/Estimating-the-Volume-of-Firewood-in-a-Tree.pdf), Ohio State University Extension (woodlandstewards.osu.edu/…0062-tree%20scale%20stick.pdf), and Oklahoma State University Extension (extension.okstate.edu/…measuring-woodland-timber-nrem-5021.pdf).
- Moisture model: Missouri Extension, G5450 Wood Fuel for Heating — extension.missouri.edu/publications/g5450 — and USDA Forest Service, Agriculture Handbook 188, Chapter 11 Energy in Kiln Drying — fpl.fs.usda.gov/documnts/usda/ah188/chapter11.pdf.
- Heat content of wood fuels: USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-282) — fpl.fs.usda.gov/documnts/pdf/fplgtr282/fpl_gtr282.pdf — and USDA Forest Products Laboratory, How To Estimate Recoverable Heat Energy in Wood or Bark Fuels (FPL-GTR-29) — fpl.fs.usda.gov/documnts/fplgtr/fplgtr29.pdf.
- Cord definition: Michigan Department of Natural Resources — michigan.gov/dnr/managing-resources/forestry/fuelwood — and Penn State Extension, Valuing Standing Timber — extension.psu.edu/valuing-standing-timber.
- Seasoning and moisture guidance: U.S. EPA Burn Wise — epa.gov/burnwise — and Michigan State University Extension — canr.msu.edu/news/tips_on_gathering_drying_and_storing_firewood.
- Michigan firewood quarantine: Michigan Department of Agriculture and Rural Development — michigan.gov/invasives/laws/dont-move-firewood and michigan.gov/invasives/laws/firewood-quarantine-faqs.
- Fuel prices and emissions factors: U.S. Energy Information Administration — eia.gov/analysis, eia.gov/environment/emissions/co2_vol_mass.php, eia.gov/tools/faqs/faq.php?id=74&t=11, and eia.gov/petroleum/heatingoilpropane.
All sources accessed 2026-10-19. The complete calculation is published in full at apicalarbor.solutions/firewood-value — the calculator on this page runs that same formula, and every input is adjustable.
Published by Apical Arbor Solutions LLC, a licensed arborist serving Mid-Michigan (Midland, Bay, Saginaw, Isabella, Clare, and Gladwin counties). Questions about a specific tree: apicalarbor.solutions.