The impacts of an ice storm on the forest canopy of a Northern Hardwood Forest

Brian Weeks

Brown University, A.B. May 2006.

The structure of a forest canopy reflects long-lasting impacts of disturbances. Ice storms can result in reductions of upper canopy leaf area, and in shifts toward late-succession species. A large ice storm impacted the forest canopy at the Hubbard Brook Experimental Forest, New Hampshire, a northern hardwood forest, in 1998. We examined the impacts of this event on the vertical structure of the forest canopy eight years post storm with our focus being on the role played by advance beech ( Fagus grandifolia ) regeneration in the recovery of leaf area. We created a foliage-height profile using two approaches: a point-quadrat approach and a pole-mounted LAI-2000 leaf area index sensor. The ice damaged areas showed an increased proportion of total leaf area at mid-canopy, largely due to increased numbers of beech saplings, although the total leaf area index between damaged and undamaged areas did not differ. The response to canopy damage is greatest in beech trees despite large beech trees being the most heavily impacted in the ice-damage. Beech will increase in importance in the forest as a result of the ice storm. These findings suggest that rare disturbances of mature hardwood forests in the northeast may lead to persistent foliage-height profile changes and an increase in beech abundance.