Diameter is the most common tree measurement mainly because it is the easiest measurement to collect. Diameter can be collected at any point on the stem, but there are some common points where diameter is taken. These include stump height, breast height, some percentage of tree height, and crown base. Of these diameter at breast height (DBH) is the most common. In English units breast height is 4.5 feet. In metric units breast height is 1.3 meters. Note that these are not the same point as 4.5 = 1.37m. Let us consider some common methods of measuring DBH.
This conversion is accomplished by dividing the circumference by PI (3.1415).
where D is the diameter, C is the circumference and PI is (3.1415).
where E is your eye, L is usually 25 inches, S is the tangent to the observed arc AB. Using the following formula you can make a Biltmore stick any where and for any L distance.
Husch, B., C. I. Miller and T. W. Beers. 1993. Forest Mensuration.
Third Edition. Krieger Publishing Co., Malabar, Florida 402 p.
Last Updated: November 19, 2001