Firewood by species / Hardwood
Extension tables · checked 2026-10-20
Black walnut firewood
A cord of black walnut holds about 22.6 million Btu of heat, according to the University of Kentucky forestry table (at 20% moisture content). That ranks it #17 of 52 species on this site, 13% more than the 20 million Btu the U.S. Energy Information Administration uses for a generic cord of wood.
- 1Heat per cord 22.6 million Btu
- 2Rank of 52 #17
- 3Dry weight 3,192 lb/cord
- 4Splitting Easy
How much heat is in a cord of black walnut?
The two extension tables used here disagree by 0.4 million Btu: Kentucky lists 22.6 and Utah State lists 22.2 (as "Walnut, Black"). The figures are close, so either one gives nearly the same answer in the calculator. Cord Calc uses Kentucky's figure because its table states the moisture basis (20%). It sits 1.9 million Btu above the median species (20.75), and it is #16 of the 38 hardwoods listed, whose average is 22.1 million Btu.
One cord of gambel oak, the highest in the table, holds as much heat as 1.36 cords of black walnut. In the other direction, a cord of black walnut replaces 1.64 cords of buckeye (horsechestnut), the lowest. In energy terms one cord equals the heat content of about 163 gallons of heating oil, using EIA's 138,500 Btu per gallon; the stove and the oil burner each lose some of that before it reaches the room.
Cords of black walnut for a winter
For the example house used across this site (2,000 sq ft, built in the 1970s, wood as the only heat, a 74% efficient stove), a normal winter takes:
| State | Degree days | Black walnut | Generic cord (20 M Btu) |
|---|---|---|---|
| North Dakota (coldest) | 9,184 | 6.1 cords | 6.9 cords |
| Oregon (median) | 5,269 | 3.5 cords | 3.9 cords |
| Florida (mildest) | 646 | 0.4 cords | 0.5 cords |
Because black walnut beats the generic cord, the stack is 12% smaller than the same winter on average wood. Your own house will differ; the calculator takes your state, floor area, house age and price.
Weight, splitting and how it burns
- Weight: Utah State lists 4,584 lb per cord green and 3,192 lb air-dried, so drying takes about 1,392 lb of water out of every cord. That is 24.9 lb per cubic foot of stacked cord, and roughly 1,596 lb for the half cord a full-size pickup bed holds.
- Kentucky's table puts a cord at 2,744 lb, 448 lb lighter than Utah State's dry figure.
- Splitting: easy (Utah State); Kentucky rates its splitting excellent.
- Burning: low smoke, few sparks, good coals, good fragrance.
- Overall rating (Utah State): excellent.
- Water in the living tree: 90% moisture content (Kentucky), on the wet side, so allow the full drying time.
Whatever the species, the heat figures assume dry wood. Seasoned firewood is below 20% moisture; fresh-cut wood is 35 to 50% water by weight (CMHC), and burning it wastes heat boiling that water off. The seasoning guide and the moisture meter guide explain how to get there and check it.
What a cord of black walnut is worth
Maine's Governor's Energy Office surveyed dealers at $355 a cord on September 21, 2026 (seasoned wood, minimum 2-cord purchase, local delivery included). Paid for as black walnut, that is $15.71 per million Btu in the wood, or $21.23 per million Btu delivered by a 74% stove. It sits in the middle of the table, so a flat per-cord price is roughly fair for it. Only two states publish a dated cord price; see Maine and New Hampshire.
Similar species
- Rocky Mountain juniper: 21.8 million Btu per cord (#18)
- Tamarack (larch): 21.8 million Btu per cord (#19)
- Hackberry: 21.7 million Btu per cord (#20)
- Slippery elm: 21.7 million Btu per cord (#21)
Compare every species on the firewood BTU chart, or see what a cord, face cord and rick hold before you buy.
Sources: University of Kentucky Forestry, Comparison of Properties Affecting Firewood (row "Black walnut"); Utah State University Extension Forestry, Wood Heating (Kuhns and Schmidt), Table 1 Firewood Facts (row "Walnut, Black"). Last checked 2026-10-20. Price: Maine Governor's Energy Office, 2025-2026 Heating Season Weekly Fuel Prices (September 21, 2026). Method: methodology.