 The most common measure of tree diameter is called diameter breast high or DBH. This is the diameter of the tree trunk at 4.5 feet above level ground on the uphill side of the tree. Measuring tree diameters at this height allows us to keep the location of tree measurements consistent. The first thing you should do before measuring DBH is to walk around the tree to see if there are any abnormalities that will impact the measurement. If there are none, then you should measure the tree at 4.5 feet above the ground keeping your diameter taped straight on the tree. If the tree is on a slope, then you should stand on the uphill side of the tree to take the measurement. If the tree is leaning, then you should measure with the tape standing behind the lean so the tape is straight on the tree and not perpendicular to the ground. If there is an abnormality on the truncate 4.5 feet, such as knots, swelling, turpentine scars, or fire scars, then DBH must be taken at another point, usually moving higher up the stem to a point where the defect is no longer affecting the measurement. Sometimes a tree forks and there are two or more main stems. In this case, if the fork starts below 4.5 feet, measure each stem individually. If the fork occurs at or above 4.5 feet, then measure at 4.5 feet and count it as a single tree stem.