Vegetation Response to Canopy Disturbance and Season of Burn during Oak Woodland and Savanna Restoration in Tennessee

The removal of fire’s influence on plant community succession has resulted in the near disappearance of oak woodlands and savannas from the Appalachian region. Negative trends in associated plant and wildlife species could be reversed if these communities are restored, but management has been limited by inadequate canopy disturbance, resprouting of woody plants, and a lack of empirical research. To address these issues, we evaluated herbaceous and woody vegetation response on the Cumberland Plateau in Tennessee to 5 replicated treatments involving canopy reduction and fire-season combinations and unmanaged controls. All categories of woody vegetation except large saplings density, but resprouting resulted in densities equal to or exceeding pre-fire levels. Herbaceous richness increased from 22 to 167 species following canopy disturbance and fire. Native cool season grasses dominated herbaceous response in treated sites. Herbaceous groundcover, richness, and diversity increased as canopy disturbance increased, and the rate of increase accelerated once basal area was reduced below 15 m2 ha-1 or 30% canopy closure. Following fire, canopy disturbance remained influential as indicated by greater herbaceous response in savannas than woodlands. Graminoid and forb groundcover, herbaceous richness, and herbaceous diversity were 24X, 11X, 9X, and 8X greater, respectively, in treatments than controls by 2012. Our results demonstrate the utility of canopy disturbance in conjunction with fire for restoring oak woodlands and savannas from closed-canopy forest conditions