Determining change of LEAN

摘要

E. Thomas Smiley and Glynn Perival of F. A. Bartlett Tree Research Laboratory look at tree lean, existing methods of measurement and the laboratory's simple new system to assess teh angle of lean. Trees that do not grow perfectly upright are often thought to be predisposed to failure (Matheny and Clark, 1994) with failure from lean corresponding to either trunk- or root-related problems. For example work in the US (the California Tree Failure Reporting Program) found that 10% of root failures and 7%of all reported trunk failures were related to a pre-failure lean (Jones and Costello 2004).