A Technical Report from The Bartlett Tree Research Laboratories 406
Trees that do not grow perfectly upright are often considered predisposed to failure. While not all leaning trees are at a higher risk of failure, some may be. Failures related to lean can either be trunk failure or root-related failures. While there is no generally accepted maximum angle of lean, the greater the angle, the greater the risk for tree failure. The worst case is when the angle of lean is increasing. If a change in lean angle is detected, the tree should be removed or other remedial action should be taken as soon as possible. This report expolores several methods that have been developed to determine if the angle of a tree trunk is changing.