How to measure a tree

Trunk Measurement

  1. Using a flexible tape measure, measure the distance around the trunk of the tree to the nearest quarter inch (circumference), or with a D-tape (diameter). This measurement should be taken at 4.5 feet above ground level.

  2. If the tree branches below 4.5 feet, it might be a multi-stem tree. To determine if the tree is a multi-stem form or not, use the pith test method as follows:  Visualize lines vertically through the center of each of the trunks. If they intersect above ground level, it would be considered a single trunk tree, and the measurement would be taken at the narrowest point on the trunk. Report the height at which the measurement was taken.

  3. If the pith lines intersect below ground level, then it would be considered a multi-stem tree, and a measurement for each stem would be taken at 4.5 feet.

  4. If the tree is on a slope, use the mid-point of the trunk and measure at 4.5 feet above ground level. If the trunk is leaning take the measurement along the trunk at 4.5 feet, measure perpendicular to the trunk.

  5. If there is a branch or growth on the trunk at or below 4.5 feet, measure at the narrowest part of the trunk and report the height at which the measurement was taken.

Height Measurement

To measure a tree’s height, a clinometer, or laser rangefinder is recommended. If none of these are available, you can estimate the height using a straight stick cut to the exact length of your arm. Walk away from the tree to a point where, by holding the stick vertically at arm’s length, the entire tree’s vertical center line is hidden behind the stick. This method works best when you are at the same elevation as the base of the tree. Measure the distance to the base of the tree — this distance will be approximately the same as the tree’s height.

Crown Spread Measurement

Measure both the widest spread of the crown and the narrowest spread of the crown. Add the two measurements together and divide by two to obtain the average crown spread.