Tools of the Trade Forestry Quiz

What is this angle gauge used for?
©Photo courtesy of Ben Meadows Company, Janesville, WI

This tool is used by foresters for:

a) opening bottles
b) measuring bark thickness
c) measuring how crowded trees are in the forest
d) checking the tread on their truck tires

The correct answer is “c.” This tool is called an “angle gauge” and is used to measure stand density. (The number of trees in an area.) The black knob at the end of the chain is held in the forester’s teeth, and the chain is stretched out horizontally. The silver gauge is held out in front of the forester at eye level. Standing in one spot, the forester turns slowly on a circle, looking at the surrounding trees through the gauge. Any tree with a trunk appearing as wide or wider that the opening in the gauge gets counted. The number of trees counted when the forester is done turning one complete circle is multiplied by either 5, 10 or 20, depending on which width opening you were using on the angle gauge. The resulting number is a measurement called “basal area.” If this number is too high, it might be time to thin out some trees so the remaining trees have more room to grow.

Mary Ann is using another type of angle gauge,
this one mounted on the end of a stick.

In this photo, Mary Ann is using another type of angle gauge, this one mounted on the end of a stick. Every tree with a trunk appearing as wide or wider than the angle gauge gets counted. This cruising stick is also used for measuring tree diameters.

On to the next question...