Restoring oak forest, woodlands and savannahs using modern silvicultural analogs to historic cultural fire regimes
Abstract
Variability in historic fire regimes in eastern North America resulted in an array of oak savannahs, woodlands and forests that were dominant vegetation types throughout the region. In the past century, once abundant savannahs and woodlands have become scarce due to conversion to agriculture, or development of forest structure in the absence of fire. In addition, the future dominance of oak forests is uncertain due to chronic low regeneration potential of oak across the region and insufficient overstory recruitment. Restoration of oak savannahs and woodlands, and sustaining oak forests are primary goals for land management agencies and conservation organizations. Insights learned from fire history research can be used to guide silviculture prescriptions to achieve these goals. Restoration of oak savannahs and woodlands requires a long-term regimen of prescribed burning, but it takes a combination of prescribed fire, timber harvesting and forest thinning to efficiently produce desired structure and composition. Sustaining oak savannahs and woodlands requires an occasional longer fire-free period to allow for replacement of the overstory by recruitment of trees from the reserve of oak sprouts that have accumulated in the understory. Prescribed fire is useful for sustaining oak forests, but it must be used judiciously to minimize timber damage and decreases in value. Integrating fire in a silvicultural prescription that uses the shelterwood regeneration method to promote competitive oak reproduction has been successfully applied in the eastern US to sustain oak forests. Restoration of oak ecosystems is possible but requires innovative combinations of traditional practices, including prescribed burning.