Fixing structures in trees under usage of tree anchors and double strapping technique
Climbing forests, tree platforms and living units above the surface in combination with trees appeal to human emotions, which can be associated with childhood dreams, the experience of nature, the appeal of the unusual or a thrill. From the point of view of structural design, however, the construction must be carried out safely and with due regard for biological aspects. After all, the trunk of a tree is part of its organism and is needed for metabolism. Through the accumulation of annual rings, it continues to be subject to annual growth in thickness. This article describes, on the basis of a concrete project, how special tree anchors and double strapping technique can be used to fix a central symmetrical construction providing a public usable area of approx. 20 m2 to a single tree in a permanent and species‐appropriate manner. In this case, the calculated vertical load of the structure (dead loads, traffic loads and snow loads) exceeds the dead weight of the supporting tree, which indicates the performance of the structure. By maintaining the tree's vitality, the load‐bearing capacity of the anchorage increases with each growth period, which is also addressed here. Other projects with similar anchoring techniques show that different tree species tolerate the proposed anchoring well, resulting in technical and economic advantages.