Gilman, E.F., F. Masters and J.C. Grabosky
Pruning affects tree movement in hurricane force wind.

Arboriculture and Urban Forestry (in press)

The goal was to determine how different pruning techniques affect trunk movement on live oak subjected to hurricane force winds. Tree movement in wind on non-pruned trees was compared to movement on trees with crowns thinned, reduced, or raised. The trees were blown using a wind generator up to 45 m/s (110 mph), maintained for three minutes. Each tree was instrumented with three Microstrain 3DM-GX1 orientation sensors at set heights along the trunk to measure its deflection in all three axes. Thinning or reducing crowns significantly reduced trunk movement at all wind speeds; whereas raising did not. This data indicates that the foliage and branches toward the top portion of the crowns are largely responsible for trunk movement in straight-line wind with those toward the bottom less important. Trees that are reduced or thinned in the manner described could receive less damage in wind storms.