Tons, Cords, and Board Feet: How Timber Gets Measured

One buyer quotes a price per ton. The next quotes a price per thousand board feet. Somebody mentions cords. You are being asked to compare three numbers that are not in the same units, on trees you have never counted.

There is no single unit for timber, in any state. Across the Southeast, pulpwood and most pine trade by the ton, which is weight off a truck scale. Sawtimber, North and South, often gets quoted by the thousand board feet, written MBF, a volume estimate of the lumber inside a log. A cord is a stack of pulpwood 128 cubic feet in size.

Then board feet come in three flavors called log rules, and the three give three different answers for the same log. Find out which unit and which rule an offer uses and the offers become comparable. Until then they are not.

Why isn't there one unit?

Because the mills at the end of the line want different things.

A paper mill or a pellet mill grinds up everything. Species and shape barely matter. What counts is how much wood mass came in the gate, and weight measures that on a scale the truck drives across.

A sawmill wants boards. How many boards come out of a log depends on diameter, length, straightness and defects. Weight tells you none of that, so sawtimber gets estimated in board feet.

Selling by weight: what a ton means

A ton is 2,000 pounds of green wood, weighed on a certified scale at the mill. Your load ticket comes back with a gross weight and a tare weight for the empty truck. The difference is your wood.

Mississippi State Extension's publication P2005, Marketing Your Timber: The Basics of Weight Scaling (print code POD-03-26), traces the switch back to the pulp and paper industry in southern Georgia, which began handling wood by weight after volume-to-weight studies in the late 1950s and early 1960s. "Today," it says, "the practice has spread throughout the Southeast." The reasons it gives are practical: logs got smaller, hand scaling got expensive, mechanized logging moved to tree-length hauling, and multi-state companies wanted one system everywhere.

The advantage for you is that a ton is a ton. Nobody's judgment is involved, and there is a printed ticket. Whether the law requires the buyer to hand you that ticket depends on your state. North Carolina does, for example. G.S. 14-135.1 requires load tickets on wood bought by the load and measured by weight, cord or board feet, and it exempts lump sum sales. Load tickets and what left your land covers what that statute says has to be on a ticket and by when. For your own state's rule, ask your state forestry agency. The National Association of State Foresters lists each one at stateforesters.org.

The disadvantage is the one the same MSU publication names outright: weight scaling does not account well for log quality. A ton of straight, clean, big-diameter red oak weighs the same as a ton of crooked, knotty red oak.

Selling by volume: cords, board feet and MBF

A cord is a stacked pile of wood measuring 128 cubic feet, usually 4 feet by 4 feet by 8 feet. North Carolina's statute, for one, uses that definition. G.S. 106-1030, which sets the state's primary forest product assessment, refers to "one standard cord, 128 cubic feet."

A stack has air in it. So a cord is not 128 cubic feet of wood. As one example, North Carolina's tax form CD-354 works from the assumption that 80 cubic feet of solid wood fills one 128 cubic foot stacked cord.

A board foot is a piece of lumber 12 inches by 12 inches by 1 inch. MBF means a thousand board feet, from the Roman numeral M. Divide a price per MBF by 1,000 and you have the price per board foot. Read MBF as "million" and you are off by a factor of a thousand. People make that mistake.

Doyle, Scribner, International: why there are three board foot rules

A log rule is a formula or table that estimates how much lumber is inside a log, from the diameter of the small end and the log's length. Three are in common use, and they do not agree.

The University of Tennessee Extension publication PB1650, Understanding Log Scales and Log Rules, by Brian Bond, revised February 2011, prints the formulas and a side-by-side table. Doyle is (D minus 4), squared, times L, divided by 16, where D is small-end diameter inside bark and L is log length in feet. Scribner came out of sawing diagrams drawn by J.M. Scribner in 1846. International 1/4-inch uses a different formula for each log length and allows for taper.

Which rule you meet depends on where you are and what you are selling. PB1650 says Scribner "is commonly used on the West Coast and in the South for pine saw logs," that Doyle "is the most common rule used in hardwood log scaling in Tennessee," and that International 1/4-inch "is generally used in timber sales in eastern national forests and state forests in Tennessee." Penn State Extension calls International 1/4-inch "the most accurate predictor of actual yield of the commonly used rules."

The table below is Table 3 of PB1650, revised February 2011, for 16-foot logs. Published figures from that publication, transcribed, not our arithmetic.

Small-end diameter	Doyle	Scribner	International 1/4-inch
6 in	4 bd ft	18 bd ft	20 bd ft
8 in	16	32	40
10 in	36	50	65
12 in	64	79	95
14 in	100	114	135
16 in	144	159	180
20 in	256	280	290
25 in	441	459	460
30 in	676	657	675

Read the top row and the bottom row against each other. That is the whole argument.

Why Doyle punishes small logs

At 6 inches, Doyle says 4 board feet and International says 20. A fifth of the volume, same log. At 12 inches, Doyle is 64 against International's 95, still about a third light. By 25 inches they are within a few board feet of each other, and at 30 inches Doyle comes out slightly higher than Scribner.

PB1650 states the reason in one line: the Doyle rule "underscales small logs and overscales large logs." Subtracting 4 inches for slab and edging is a flat deduction, and on a small log a flat deduction eats a much bigger share.

Mississippi State Extension's publication P2244, Pine Timber Volume-to-Weight Conversions (print code POD-01-26), shows the same effect from the other direction. Its sawtimber conversions are tied to Doyle, and they run from 14.0 tons per MBF for pine at 10 inches DBH down to 4.4 tons per MBF at 36 inches DBH. Same species, same rule, Mississippi timber. It takes more than three times the tonnage to make a thousand Doyle board feet out of small trees as out of big ones.

This is not a scandal. It is a known property of an old rule, and everybody in the trade knows it. It matters to you for one reason. If your stand is small-diameter, a Doyle quote and a per-ton quote describe very different pictures of the same trees.

How many tons is a thousand board feet?

A range, and the range depends on which rule you are converting from.

Check whether your own state's price report prints conversion factors, and which rule it ties them to. Here is one that does. NC State Extension publishes the North Carolina Standing Timber Price Report quarterly under an agreement with Timber Mart-South, at forestry.ces.ncsu.edu. Prices there run in dollars per ton, and on the 2025 and 2026 reports, its North Carolina conversion factors are:

Product	Factor	Rule
Pine sawtimber	7.0 tons per 1,000 bd ft	Scribner
Pine chip-n-saw	8.0 tons per 1,000 bd ft	Scribner
Pine pulpwood and chip-n-saw	2.68 tons per standard cord	n/a
Hardwood sawtimber	9.0 tons per 1,000 bd ft	Doyle
Hardwood pulpwood and chip-n-saw	2.9 tons per standard cord	n/a

Notice the pine figure is tied to Scribner and the hardwood figure to Doyle. Change the rule and the factor changes with it.

MSU's P2005, working in Mississippi, gives typical mill conversions of roughly 8 to 10 tons per MBF for pine sawlogs and 9 to 11 tons per MBF for hardwood. Different state, different mills, and the publication names no rule. It also says there is no universal fair weight: trees of one species vary in weight from place to place, log diameter changes lumber yield, mills differ in efficiency, and quality is not captured.

So a firm tons-per-MBF number with no rule attached and no source tells you something about whoever said it.

Is there a legal weight for a cord?

That depends on the state, and even where one exists, check what it governs.

Mississippi did legislate standard pulpwood cord weights in 1983, and P2005 lists them: 5,200 pounds for pine, 5,400 for soft hardwood, 5,600 for mixed hardwood, 5,800 for hard hardwood. Those are Mississippi statutory figures. Outside Mississippi they do not govern anything on your tract.

North Carolina sets no legal cord weight for your sale. The nearest North Carolina equivalent is a tax computation. Form CD-354, the Primary Forest Products Tax Return, revision 12-13, prints these factors: 12,000 pounds equals one thousand board feet International for softwood, 14,000 pounds for hardwood, 5,300 pounds per standard cord softwood, 5,800 pounds per standard cord hardwood. That is a mill's quarterly return to the Department of Revenue. It has nothing to do with what a buyer pays you. To find out whether your state sets a cord weight, and what it applies to, ask your state forestry agency.

What weight does not tell you

Quality. Short list, important one.

Weight cannot see a sweep in the stem, a shake in the butt log, metal from an old fence, or the difference between a veneer-grade white oak and a pallet log. On pulpwood that mostly does not matter. The mill grinds it anyway. On hardwood sawtimber it matters enormously, which is one reason hardwood more often sells on log scale.

Weight also varies with moisture. P2244 puts it directly: "The weight of wood is determined by moisture content and specific gravity. These vary from tree to tree, making the exact volume-to-ton conversion for your timber different." North Carolina, for one, publishes no figure for how much that moves in practice. Weigh the same thousand board feet in February and in August and you get two answers.

How do I check the math on my own sale?

Four steps. None require a scale stick.

1. Ask the buyer, in writing, which unit and which rule. "Per ton, delivered scale" and "per MBF, Doyle" and "per MBF, International 1/4-inch" are three different deals. A buyer who will not put the rule in writing has told you something.
2. Keep every load ticket. Add the tons. Sold by the ton, that sum times your price, minus whatever the contract says comes off, should land on your check. If it does not, the tickets are your evidence.
3. Convert before you compare. Put both offers into the same unit using the factors above, and write down which rule you used. Getting the same answer twice is the point, not getting an exact answer.
4. Get somebody with no stake in the sale to cruise it first. A consulting forester works for you and gives a volume estimate by product class before any buyer sees the tract. That is the only way to know whether an offer is high or low. Whether you need a forestry consultant covers what they do and how they charge.

What stumpage value is covers what a price per unit represents. Thinking about dealing with a mill directly? Read selling timber directly to a mill first, because mill scale rules are the mill's rules.

Two questions to ask the next buyer who calls

Pull up your state's timber price report and open the most recent one. Our timber prices by state page shows what your state publishes, or the nearest market that does, and whose figures they are. Write down the price for each product that grows on your land, the unit it is quoted in, and any conversion factors the report prints. In North Carolina, for example, that report is at forestry.ces.ncsu.edu, and it prints prices per ton and conversion factors together.

Keep the paper by the phone. When a buyer calls, ask two things. Which unit. Which rule. Then convert the offer to the report's unit and see where it sits.

A statewide average will never tell you what your trees are worth. It will tell you whether the number you were handed is in the same country. For the real answer on your own tract, how to sell timber on your land walks through the order to do things in.