Dendrometer

This angle gauge (Dendrometer) is a variation of the original tool invented by Prof. Horst Kramer in the early 1980's at the University of Göttingen. Foresters use a Dendrometer to get a quick estimate of the basal area (m²/ha) of a forest stand. The method of "angle count sampling" goes back to Walter Bitterlich, who proposed a plot design in which trees around a sampling position are included based on a defied opening angle, which allows determining their design-based inclusion probability.
In addition to the printed model, you need a 2 mm thick non-strechy cord of ~ 110cm length. For further explanation of the concept, see https://youtu.be/JaBAwHKvICE?si=rDuFQV8-qhMqo7cU
The tool is mainly intended to be used for teaching purposes in our lecture.