Diameterklasser

Diameterklasser, or diameter classes, are a system for categorizing trees by trunk diameter, typically measured at breast height (DBH). This approach is most commonly used in forestry and forest management to summarize stand structure, growth potential, and timber volume in a compact form.

In practice, trees are assigned to predefined diameter intervals, such as 0–9 cm, 10–19 cm, 20–29 cm, and so on. The exact boundaries and class widths vary by country, protocol, and project. Field data are collected in plots where diameters are measured with a diameter tape or calipers. In many inventories, DBH is complemented by height measurements and species identification to improve volume and biomass estimates.

Diameter classes support a range of applications, including assessment of age structure, planning of thinning operations, and calculation of growing stock for harvest scheduling. They also facilitate aggregation of data over large areas, enabling policymakers and foresters to monitor stand development and to model future yields under different management scenarios.

Advantages of diameter classes include ease of measurement, robustness across varied conditions, and the ability to produce quick summaries of complex stands. Limitations arise from the loss of detail within each class; results can depend on the chosen class boundaries, and biomass estimates may require species- and allometry-specific models.

The concept is widely used in forestry but the general idea—classifying objects by diameter—appears in other disciplines as well, where particle- or object-size distributions are analyzed in similar, though context-specific, ways.