Diameter at breast height

With diameter at breast height ( DBH ), the diameter of a standing tree trunk at breast height is called. The BHD is determined in forest stands recordings for determining in particular the wood mass. The more suitable for this diameter in the middle of a tree trunk can be established only with great effort, so that one is satisfied in general with an easy measurement to be performed at chest height. At this height is in most trees the influence of the buttresses to the diameter no longer present and the diameter values ​​have close relationships with other statistical characteristics of a portfolio ( eg floor area, height or volume) on. To determine the inventory volume there are appropriate volume boards.

The BHD is determined in Central Europe at a height of 130 centimeters above the ground. In other regions, other heights are used (Japan: 137 cm; U.S.: 4.5 feet, which is about 137 cm, while in other countries with non- metric measure often 5 feet, about 150 cm).

Measurement

The measuring instrument is usually an caliper. But it can also be used diameter tapes, which determine the diameter indirectly over the circumference. The measurement with the caliper ( Kluppung ) are doubly cross ( 90 ° apart ) and there is an average of the two measurements determined. With strongly oval tree cross section, the Kluppungen the narrowest and widest point are averaged. If there are branches at breast height, bumps or growths, is measured above and below it and the mean.

For trees that are growing on a slope, the chest is determined by 1.3 meters on the slope - top (A in the figure). For particularly thick trees, the measurement of the slope - top gives a higher measurement point. The actual diameter growth of the tree, especially with a tapered stem ( abholzig ) is reproduced reduced. It makes sense, with thick trees no longer used for the timber industry come into question, the measurement center to the stem axis (B in the figure), the presumed seed point to make. Under this method, the German tree Archives carries out its measurements, but in 1 meters instead of 1.3 meters in height.