First Steps Toward Defining the Wind Disturbance Regime in Central Hardwoods Forests

Abstract

Wind disturbance is one of the most prevalent natural disturbances in the Central Hardwoods Region (CHR). All ecoregions within the CHR are subject to a greater or lesser degree to tornado, derecho or thunderstorm wind damage, with an east-to-west increase in the importance of tornadoes and derechos. At the regional scale, hurricanes decrease in importance with distance from the Atlantic and Gulf coasts. The disturbed patch sizes created by these various storms include occasional very large (e.g., >25 ha) patches, but the great majority are a few ha or less, perhaps differing from common visual impressions. Hurricane and derecho disturbance patterns appear to be more predictable in relation to topographic features, whereas tornado damage is much more stochastic. All wind disturbance types cause greater damage to larger trees, and most studies reveal interspecific differences in levels of wind damage, although such patterns are not always consistent among studies or locations. Wind disturbance commonly advances succession in second-growth forest but may set succession back in primary forests. The greatest research needs are landscape-scale patterns of damage; relationships of damage to topography and soils; clarifying the tree characteristics (e.g., architecture, wood strength, rooting depth) that underlie interspecific differences in vulnerability; and documenting ecosystem effects of wind disturbance.