Examining formulas that assess strength Loss due to decay in trees: woundwood toughness improvement in red maple (Acer rubrum)    (View PDF)

Brian C.P. Kane and H. Dennis P. Ryan III

Abstract: Hazard trees are a concern for anyone who manages trees in a landscape setting, including arborists, urban foresters, and grounds managers. Through research, experience, observation, and common sense, arborists and urban foresters have identified many risk factors that predispose trees to failure. They have also developed thresholds to help determine the degree of hazard, whether a tree is in imminent danger of failing or needs annual (or more frequent) inspections. Two critical factors are involved in strength loss assessment in tree stems with defects. First, it is important to know how much tree strength is lost due to a defect such as a hollow or cavity. Second, the load required to cause failure needs to be considered since the wood of some trees can endure greater mechanical stress than others. Tests of woundwood and normal wood in red maple (Acer rubrum) trees from Massachusetts, U.S., showed woundwood to exhibit consistently greater toughness measures compared to normal wood. There was, however, no correlation between the degree of toughness improvement in woundwood and the severity of decay (calculated as the loss in moment of inertia of the stem). Woundwood toughness improvement appears to be an additional safety factor in red maple trees that reduces the risk of failure due to trunk decay.

Keywords: Hazard tree; tree moment of inertia; decay; mechanical stress.

https://doi.org/10.48044/jauf.2003.024