The stem piece of the hawthorn originates from investigations for the "Stuttgarter Festigkeitskatalog (Stuttgart Strength Catalog)" which was compiled mainly under L. Wessolly in the 1990s in the Institute for Model Structures (summarized: L. Wessolly and M. Erb: Handbuch der Baumstatik, 1998, in University Library: 4 Na 890).
Strengths of living ("green") timbers were measured in order to obtain data for the necessary advanced calculations for expert opinions on the strength of endangered trees of many species. The failure of the stems of trees is usually not due to tension, but to compression, i.e. if the trunk bends strongly in a storm, it is on the compression side! Therefore, compression tests were particularly important. Our piece comes from the compression test with the hawthorn stem.
The "Stuttgarter Festigkeitskatalog" is still used today by tree structural engineers (see determination of basic safety by means of the statically integrated tree assessment - SIA), but there are also contradictions to it in literature - this, however, is a topic of structural engineers, not botanists.
