Storm Wind Loads
University Outreach Publication
Monograph on storm wind loads on trees, storm wind scales, and significance on tree failures.
Trees must withstand wind to survive. Wind and gravity both impact trees in storms, but the dominant load is from wind. Storm winds push on tree crowns and stems causing root plates to rock. The result of storm winds is twisting and bending of tree parts causing either the part to fail or the supporting soil to fail. Treessense structural stress and attempt to minimize failures through reactive growth. Trees modify their structureover time as they are challenged by wind. Trees are biologically designed to sustain average wind loads. Whatare the loads applied by storms to trees?
A tree has a large sail area (leaves and twigs) held upright high into the air by a tapered mast (stem). The stem is woven onto a thick horizontal mat of large structural roots at the stem base which forms a rootplate. Rapidly tapering roots grow away from the stem base provide a tree with an absorbing surface. Thecenter of gravity (effective weight center) of a tree is usually somewhere in the middle of the stem above the root plate. Gravity is pulling down on the tree all over but has a total effect focused at the center of gravity. Wind ispushing the tree around its center of gravity.
WSF&NR08-24
Dr. Kim D. Coder
July 2008
Warnell School, University of Georgia
Athens, GA, USA
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Click here to download article as a PDF.
WSF&NR08-24
Canopy, Disaster, Engineering, Landscape Ecology, Protection (tree), Safety Issues, Storms, Storms (general), Storms (hurricane), Storms (ice), Storms (tornado), Structure (tree)
Georgia, National, Eastern, Great Plains, Mid-Atlantic, Midwest, North Central, Northeast, Piedmont, Southeast, Southern, International
Other
