Understanding your estimate
Black walnut is valuable enough that landowners are routinely offered less than fair value by buyers who know the seller has no independent number to compare against. A rough calculation like this one will not replace a forester's cruise, but it tells you whether a quoted price is in the right neighbourhood.
Measuring DBH correctly
Diameter at breast height is measured 4.5 feet up the trunk from the ground, on the uphill side if the tree is on a slope. Wrap a tape measure around the trunk to get circumference, then divide by 3.14 (pi) to get diameter. Measuring at a different height, or across buttressed roots near the base, will throw the estimate off.
Grade matters more than diameter
Two trees with identical DBH can be worth five times apart based on grade alone. Veneer logs — nearly defect-free, 18 inches minimum diameter, dead straight — are sliced into thin sheets for furniture and command the top price. Everything else is sawlog, graded down by knots, sweep, stain and metal. Assume sawlog grade unless a buyer specifically confirms veneer potential.
| Grade | Requirements | Typical range |
|---|---|---|
| Veneer | 18"+ diameter, straight, defect-free on all faces | $8–15/bf |
| Select sawlog | Good diameter, minor defects only | $4–6/bf |
| Common #1 | Usable diameter, visible defects | $1–3/bf |
| Common #2 | Marginal quality, heavy defects | $0.50–1.50/bf |
Ranges are broadly indicative and vary by region and season. They are not a live feed — always get a local quote before selling.
Why the calculator estimates small-end diameter
The Doyle rule uses the diameter at the small end of the log, which on a standing tree is hard to measure directly. This tool estimates it as 80% of DBH, a reasonable approximation for a moderately tapered hardwood trunk. A very straight tree with little taper will scale higher than this estimate suggests; a heavily tapered one will scale lower. A buyer's own scale after felling is the only figure that actually matters for a sale.
Before you sell
- Get more than one quote. Prices for the same tree can vary widely between buyers.
- Hire a consulting forester for anything beyond a single tree. Their fee is typically small next to the improvement in the price you negotiate.
- Check for metal. Old fence wire or nails grown into a trunk can destroy a sawmill blade and tank the value of an otherwise excellent log.
- Time it right. Winter harvest, when sap is down and ground is firm, generally brings better prices and less site damage.
Three worked examples
An 18-inch DBH tree, 10 ft clear log
Small-end estimate: 18 × 0.8 = 14.4 in. Doyle: (14.4 − 4)² × 10 ÷ 16 = 68 board feet. At common-grade prices of $1–3/bf that's roughly $70–200 — a tree this size is usually still below the 18-inch veneer minimum.
A 20-inch DBH tree, 8 ft clear log
Small-end estimate: 16 in. Doyle: (16 − 4)² × 8 ÷ 16 = 72 board feet. Shorter log length keeps the total close to the 18-inch example above despite the larger diameter — length matters as much as girth in this formula.
A 30-inch DBH tree, 14 ft clear log — potential veneer
Small-end estimate: 24 in, comfortably over the 18-inch veneer minimum. Doyle: (24 − 4)² × 14 ÷ 16 = 350 board feet. At sawlog prices ($3–5/bf) that's $1,050–1,750; at veneer prices ($8–15/bf), assuming the log is straight and defect-free enough to qualify, $2,800–5,250 — the same tree, five times the price, purely on grade.
Timber terms, plainly
- DBH — Diameter at Breast Height
- Trunk diameter measured 4.5 feet above ground level, the standard reference point foresters use so measurements are comparable between trees.
- Board foot
- A unit of lumber volume equal to a piece 12 × 12 × 1 inches. Log volume in board feet is an estimate of usable sawn lumber, not the log's full physical volume.
- Doyle log rule
- One of several formulas for converting log dimensions into board feet. It's the most conservative of the common rules and the one most hardwood buyers in the eastern US quote against.
- Merchantable height
- The length of trunk that's straight and defect-free enough to saw into lumber — usually up to the first major fork, large branch, or visible defect.
- Veneer
- The top log grade, sliced into thin sheets for furniture and panelling rather than sawn into boards. Requires large diameter, straightness and near-total absence of defects — most standing walnut doesn't qualify.
Before you sell
- Get more than one quote. Prices for the same tree can vary widely between buyers.
- Hire a consulting forester for anything beyond a single tree. Their fee is typically small next to the improvement in the price you negotiate.
- Check for metal. Old fence wire or nails grown into a trunk can destroy a sawmill blade and tank the value of an otherwise excellent log.
- Time it right. Winter harvest, when sap is down and ground is firm, generally brings better prices and less site damage.
Taking the tree out entirely? The Land Clearing Cost Calculator estimates removal costs, and the Tree Spacing Calculator helps plan what replaces it.