breakage of the trunk of a tree by wind. Mass storm windfall is observed after severe gusty winds (gales). Species of trees with porous, brittle wood, and especially trees afflicted with rot (spruce, fir, pine, aspen, birch, larch, and, less frequently, oak) suffer from storm windfall. Mature and overmature plantings are especially damaged. Systematic managed cutting (thinning out of undesirable trees in order to create more favorable conditions for the more valuable ones), maintenance of tree stands in good hygienic condition, and the creation of windbreaks are recommended for the control of wind breakage of wood.