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Published on: April 20, 2016
Computing factors of safety against wind-induced tree stem damage
1Department of Plant Biology, Cornell University, Ithaca, NY 14853, USA. kjn2@cornell.edu
Journal of Experimental Botany
|August 12, 2000
Summary
Wild cherry trees strategically develop weaker stems to reduce wind drag on older parts, preventing catastrophic failure. This natural adaptation ensures tree stability by managing mechanical stress distribution.
Area of Science:
- Biomechanical Engineering
- Forest Ecology
- Plant Physiology
Background:
- Trees must withstand environmental stresses, particularly wind, to survive.
- Understanding stem mechanics is crucial for predicting tree stability and failure.
Purpose of the Study:
- To estimate drag forces, bending moments, and stresses on wild cherry tree stems.
- To calculate the factor of safety against wind-induced mechanical failure.
Main Methods:
- Drag forces calculated using stem projected areas and wind speed measurements.
- Bending moments and stresses analyzed along the stem length.
- Factor of safety determined using mean breaking stress of wood samples.
Main Results:
- Drag forces and stresses increase towards the tree base.
- Factor of safety varies sinusoidally, with highest safety in distal stems and lowest near the base.
- Geometrically self-similar stems exhibit higher safety factors than those with elastic or stress self-similarity.
Conclusions:
- Trees maintain stems prone to wind damage as a strategy to reduce overall drag and prevent catastrophic failure.
- This pattern of stem vulnerability contributes to the long-term mechanical integrity of the tree.
- Stem taper geometry significantly influences safety factors, more so than wind profile geometry.
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