Ice storm damage to upland oak-hickory forest at Bernheim Forest, Kentucky1

Ice storms are one of the main causes of disturbance and mortality in oak forests and can occur more frequently than wind storms, fire, diseases, and insect outbreaks. The effects of the 2009 ice storm on the tree species were studied in an upland oak-hickory forest at Bernheim Forest, Kentucky. Approximately 14% of the trees showed some damage from the ice storm with Ostrya virginiana, Acer rubrum, and Quercus rubra being the most susceptible to damage. Quercus velutina, Quercus alba, and Sassafras albidium were least susceptible. Pole size trees were more vulnerable to damage than sapling and sawtimber. Trees found in the midstory, and on the eastern slope had more damage from the ice storm than the other trees. Immediately following the ice storm, seedlings showed a high mortality, and it took until 2011 before most species returned to pre ice storm levels. Seedling numbers did not return to pre ice storm levels on the ridgetop and western upper slopes, which are more vulnerable to drought. By damaging the A. rubrum more than the Quercus and Carya species, and opening the understory, the ice storm is reducing midstory canopy and may be changing the composition of upland oak forests.