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

Arboriculture and Urban Forestry 34 (1): 20-28

The goal of this study was to determine how different pruning techniques af fect trunk movement on live oak subjected to hurricane force winds. Tree movement in wind on nonpruned trees was comp ared with movement on trees with crowns thinned, reduced, or raised. Twenty trees were blown using a wind generator up to 45 m /s (110 mph) maintained for 3 min. Each tree was instrumented with three orientation sensors at set heights along the trun k to measure its deflection. Thinning or reducing crowns significantly reduced upper trunk movement at all wind speeds, whereas ra ising did not. Lower trunk movement was not affected by pruning type. These data indicated that foliage and branches toward the top of tree crowns were largely responsible for trunk movement in straight-line wind with those toward the bottom less importan t. Trees that are reduced or thinned in the manner described could receive less damage in windstorms.
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