Effects of Ice Storms, Southern Pine Beetle Infestation, and Fire on Table Mountain Pine Forests of Southwestern Virginia

Abstract

Forests dominated by Table Mountain pine (Pinus pungens) cloak xeric sites in the Appalachian Mountains. Frequent fire and other disturbances probably maintained open pine stands in the past, but fire-exclusion promoted increased stand density and hardwood invasion. In stands we sampled, most Table Mountain pines belonged to a cohort that originated in the early 1900s, probably following a severe burn. Recent disturbances changed the stands considerably. Ice storms reduced the basal area of one stand by about 23%, lowering the abundance of pines more than hardwoods. Subsequently, a southern pine beetle infestation removed 30% of the remaining pine basal area. These disturbances stimulated little pine regeneration. In a neighboring stand disturbed by wildfire as well as the ice storms and pine beetles, the abundance of both hardwoods and pines declined dramatically. Basal area loss in the stand was 45%. The burn top-killed many of the hardwood trees and shrubs, which comprised a dense understory, and stimulated abundant Table Mountain pine regeneration. Our results suggest that without fire, long-term maintenance of Table Mountain pine is improbable. Periodic disturbances by ice storms and pine beetles are hastening the loss of pine stands from most portions of the landscape.

Keywords:

• Appalachian Mountains
• disturbance
• ice storm
• freezing rain
• Pinus pungens
• Dendroctonus frontalis