Träddiameter

Träddiameter refers to the width of a tree trunk, usually measured as diameter at a specified height. In forestry, the standard reference is diameter at breast height (DBH), defined as the trunk diameter measured at 1.3 meters above ground. The term is used in Swedish contexts to compare tree size across species and stands.

Measurement methods vary in precision and practicality. The simplest tool is a diameter tape that wraps around the trunk and provides the diameter including bark. For smaller trees, calipers or diameter tapes graded for small diameters can be used. For large or irregular trunks, non-destructive methods such as terrestrial LiDAR, acoustic tomography, or imaging-based approaches may supplement or replace direct tape measurements. In some cases, bark thickness is considered separately when a more accurate assessment of wood diameter is needed.

DBH is central to many forestry calculations. It relates to basal area, calculated as π times the square of DBH divided by four, which represents the cross-sectional area of a tree at that height. DBH, together with height, feeds allometric or volume equations to estimate timber volume, biomass, and growth. Dose of information from DBH distributions across a stand informs management decisions, thinning schedules, and ecological studies of competition and habitat structure.

Variations and caveats exist. Trunk diameter changes along the trunk due to taper, so DBH is only one snapshot of size. Measurements should follow standardized procedures (height, inclusion of bark, instrument calibration) to enable comparisons across times and sites. For multi-stemmed individuals, multiple diameters may be recorded or an alternative size metric selected.