The Amazing Biltmore Stick and Cruiser Tool

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What is a Biltmore or Cruiser Stick?

biltmore stick
(Michigan Technological University)

The "Biltmore stick" or cruiser stick is an ingenious device used in cruising and measuring trees and logs and to estimate lumber. It was developed around the turn of the century based on a principle of similar triangles. The stick is still very much a part of a timber owner's tool kit and can be purchased at any forestry supply center. You can even make your own.

This scaling tool is a straight wooden stick, similar in appearance to a yard stick. The Biltmore stick is graduated for direct readings of tree diameters and heights. The stick allows you to measure the diameter at a point 4.5 feet above stump height and also the merchantable height in terms of 16-foot logs from a distance of one chain (66 feet). With these two measurements, the board foot volume of the tree may be determined. The actual volume table is printed on the stick.

This step-by-step feature will take you through the entire process of using a cruiser stick. You will be shown how to determine tree height, diameter and total merchantable volume.

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How to Measure Tree Diameter with a Biltmore Stick

the Biltmore Scale diagram
(University of Kentucky)

Stand squarely in front of the tree and hold the stick face flat against tree and in a horizontal position at right angles to your line of sight. The stick must be held against the tree at diameter breast height (a spot 4.5 feet above the stump height is referred to as"dbh") at a predetermined distance (25") from the observer's eye. Read the diameter directly from the "Diameter of Tree" side of the stick.

The user's perspective view is compensated for by the dbh graduations (inch marks get shorter as tree diameter increases) which makes it possible to measure a 40-inch diameter tree with a 25 inch long Biltmore stick. Most commercial scaling sticks are calibrated for using at a distance of 25" from the eye and the stick length can also be used to measure eye to tree distance.

Because of the difficulty maintaining exact distance and keeping the stick in the absolute vertical or horizontal, the stick must be regarded as a fairly crude measuring device. The cruising stick is handy for quick estimates but is not generally used by foresters for generating precise cruise data.

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How to Measure Tree Merchantable Height with a Biltmore Stick

measuring tree heights diagram
(University of Kentucky)

Merchantable height refers to the length of usable tree and is measured from stump height to the cutoff point in the top. The cutoff point will vary depending on locality, product and the number of limbs.

Stand 66 feet (approximately 12 paces) from the tree you want to measure. Hold the stick in the upright vertical position 25 inches from your eye with the "number of 16-foot logs" side of the stick facing you. Usually, this is on an edge of the stick.

The number of logs can be read directly off the stick starting upward from the estimated stump height. You are actually not measuring total height but are estimating 16-foot log sections. With this merchantable height estimated in logs, plus the diameter, you can estimate tree volume.

You can also estimate the total height of the tree by counting each 16-foot length and adding them together for a total height. Every total tree height will not come to an even log. Prorate the last log into feet by using a proportional estimate.

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How to Scale Tree and Log Volumes with a Biltmore Stick

(Sabine Thielemann/EyeEm/Getty Images)

To measure tree volume: Hold stick against the tree at diameter breast height (dbh) 25 inches from your eye.

Shift stick to the right or left side of the tree until the zero or left end of the volume side of the stick lines up with the left edge of the tree. Sighting the right side of the stick where it touches outside bark (only moving your eyes) gives you the diameter on the top line and below this the number of board feet for trees of different numbers of logs.

Say you scaled a 16-inch diameter tree with three logs. If you have a Scribner scaling stick you would calculate that the tree has approximately 226 board feet. To accurately measure lengths and diameters, you must hold the stick in the exact vertical or horizontal.

To measure volume of logs: Position the "log diameter" scale across the small end of the log by placing the stick across the place that appears to be average diameter (or take several readings and average). Log volumes for different diameters and lengths from 8 to 16 feet can be read on the flat side of the stick marked "log scale."

Say you scaled a 16-foot log that averaged 16 inches on the small end. Looking at the log scale where these numbers correspond you would read 159 board feet Scribner log rule.

Logs over 16 feet long are scaled as two logs allowing for taper on logs 22 feet or longer. A 20-foot log, for example, 15 inches in diameter, would be scaled as two 10 foot logs, each 15 inches in diameter.