The method of Visual Tree Assessment (VTA) described here is a method of tree diagnosis that is used world-wide and is legally accepted. It interprets the body language of trees, linking internal defects to the tree’s own repair-structures, confirming and measuring these defects, and finally assessing them with failure criteria, and from this, deducing measures for the “therapy” of the tree. Accordingly, trees that are only apparently dangerous should be distinguished from trees that a really dangerous, thus avoiding unnecessary fellings and also accidents caused by tree failure.
The contents are presented in the form of a concise field guide.
Please note, that even a healthy tree can fail because trees have a natural failure rate. They pay with losses of individuals to maintain the species with minimum weight.