Southeastern Pine Savannas

Southeastern pine savannas are characterized by widely spaced overstory trees and a rich groundlayer dominated by grasses.  They are pyrogenic systems that burn frequently (typically every 1 to 3 years), historically by natural lightning initiated fires.  Remaining pine savannas are small and fragmented so that prescribed fires are now often required.  Hardwood tree species are less fire tolerant than savanna pines and become established in areas with reduced fire frequency.  This can be a very localized process that results in a spatially heterogeneous system where open savannas dominated by pines are intermixed with hardwood patches.  The balance between hardwood encroachment and savanna expansion is sensitive to fire frequency.  Fire frequency is, in turn, strongly influenced by the vegetation itself, which can give rise to nonlinear dynamics.

 I am broadly interested in southeastern pine savannas to include pine demography, savanna-forest dynamics, and patterns of understory species diversity.  My current research is focused on understanding the mechanisms that create and maintain these pinelands as savannas.  The savanna physiognonmy is likely related to fire disturbance although how fire interacts with vegetation to produce low tree densities and the striking spatial patterns found in pine savannas is unclear.  Hurricanes and lightning are also frequent disturbances in these systems and may have an important role in structuring pinelands as may below-ground competition.  I am pursuing these research interests at two sites, one in Georgia and the other in Florida, working closely with Dr. Bill Platt of Louisiana State University.