Tree Work
Tree Wind Load Calculator
Pressure rises with the square of wind speed. A canopy that catches 40 mph wind sees 4× the force of one in 20 mph wind. Enter the projected area facing the wind and wind speed.
Wind force (lb)
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- Dynamic pressure (psf)
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- Drag coefficient used
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- Approximate wind class
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FAQ
Where does q = 0.00256 V² come from? +
Standard ASCE 7 dynamic-pressure equation for U.S. units. V in mph, q in pounds per square foot. Multiply by Cd and projected area for force.
Why does drag coefficient matter? +
Bare branches let wind pass through (low Cd). Leafy canopies catch more (higher Cd). Coniferous evergreens with dense needles can be even worse — same area, more catch.
Do I need to worry about this for normal removals? +
For most jobs, no — wind well below 25 mph is barely a factor. Above 40 mph wind, large trees experience tens of thousands of pounds of force and rigging assumptions stop holding.