ABSTRACT
The sampling design described in this chapter is applicable chiefly to standing trees. It was first articulated by Walter Bitterlich (1949) under the German name Winkelsählprobe, which translates into English as ‘angle-count sampling.’ An Austrian forester, Bitterlich began as early as 1931 (see Bitterlich 1984) to think about distances between neighboring trees in the forest and the geometric interrelationships between them. From these musings sprang an ingenious probability-proportional-tosize sampling design that allows for the precise estimation of aggregate basal area per hectare merely by counting trees that are selected for the sample. Shortly after Bitterlich’s initial publication of the method, an American forester, Lewis R. Grosenbaugh, discerned the probabilistic basis of angle-count sampling, deduced its applicability for estimating characteristics of the forest other than basal area, and he coined the term ‘horizontal point sampling’ (Grosenbaugh 1952, 1958). Other names that have appeared for this sampling design are Bitterlich sampling, variable radius plot sampling, Relaskop sampling, point sampling, plotless sampling, and prism sampling.
