Ecological impact of a microburst windstorm in a northern hardwood forest

Abstract

We quantified damage by a microburst windstorm to a northern hardwood forest (Hubbard Brook Experimental Forest, New Hampshire). These storms may be important in regulating the structure and composition of forests of the northeastern United States, but few studies of damage patterns from microbursts have been reported. In the 600 ha area most heavily impacted by the microburst at Hubbard Brook, 4.6% of the canopy was removed. Although most disturbances were small (<200 m2), much (22%) of the area damaged by the storm was associated with one 5.2 ha blowdown within which 76% of the trees suffered severe damage. Roughly one-half of the damaged trees were uprooted and one-quarter were snapped off, with few differences among tree species. The remaining trees in the blowdown either avoided damage or suffered less severe damage (i.e., leaning but not snapped or uprooted). Regeneration of shade-intolerant (pin cherry (Prunus pensylvanica L. f.)) and mid-tolerant (yellow birch (Betula alleghaniensis Britt.), red maple (Acer rubrum L.)) trees was present in the large canopy gaps. While recruitment opportunities in these large gaps may be important for maintaining populations of pioneer species, the limited spatial extent of microbursts suggests that they play a minor role in the overall dynamics of the northeastern forest.