|This experiment was set up to respond to the common concern that partial cutting increases the risk of windthrow, to assess the extent of windthrow in the four levels of harvest, to examine the direction of the windthrow in order to help design more windfirm boundaries and retention patches and to examine individual tree / microsite susceptibility to windthrow damage.|
|Windthrow in unharvested treatment area||Radial graph showing windthrow direction|
K.D. 1997. Windthrow damage two years after partial cutting
of the Date Creek silvicultural systems study in the Interior Cedar-Hemlock
forests of northwestern British Columbia. Can. J. For. Res. 27:1695-1701.
Abstract: Partial cutting that removed either 30 or 60 percent of the volume as single trees or small groups up to 0.5 ha had little effect on wind damage to merchantable trees (³ 17.5 cm diameter). On average, 6.7 stems per hectare of windthrow occurred across unlogged and logged units, representing approximately 1.9% of the standing trees. Over two years, 0.63 m2 ha-1 of merchantable basal area was damaged or 1.5% of the original standing basal area. In the partial cuts, 2.2% of the trees were damaged compared to 1.1% in unlogged areas. The 1.1% increase in damage in partial cut units was well below the 10% effect size considered large enough to warrant either management intervention or to deem the partial cutting a failure. The greatest wind damage occurred in the old-growth stands. For 8 of the 9 tree species examined, no individual tree characteristics seemed to predispose them to wind damage. Abies amabilis (Dougl. ex Forbes), Populus tremuloides (Michx.) and Abies lasiocarpa ((Hook.) Nutt.) were the most susceptible species to windthrow.
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