Analytical fragility curves for trees subject to ice loading in a changing climate

Recent severe ice storms across the United States severely damaged trees resulting in extensive electrical power outages. Furthermore, trees and branches can fall on nearby roads, blocking traffic flow and reducing the safety of drivers. In this study, trees subjected to ice loads were analyzed using the finite element method and Monte Carlo simulation to develop analytical fragility curves. Two-dimensional, fractal trees were constructed with randomly generated geometric and mechanical parameters for four deciduous tree species: Acer saccharum, Tilia americana, Fagus grandifolia, and Quercus alba. Two load case scenarios were considered - with and without the effects of leaves - which were then subjected to varying ice accumulation thicknesses. The resulting fragility curves suggest that leaves have a substantial impact on tree branch damage under ice loads, which is significant because of the increase in unseasonably early ice storms due to climate change.

Automated summary

Recent ice storms in the United States have caused severe tree damage and widespread power outages. Falling trees and branches can block roads and endanger drivers. This study used finite element method and Monte Carlo simulation to analyze trees under ice loads and develop fragility curves. The findings show that leaves significantly affect tree branch damage, which is important due to the increased frequency of early ice storms caused by climate change.