Clear-Cuts Are Not Clean Slates: Residual Vegetation Impediments to Savanna Restoration


Milton H. Diaz-Toribio

Additional Authors:

Francis E. Putz



Fire suppression, hardwood invasion, hardwood removal, resprouting, seed bank.

ABSTRACT In response to widespread losses of savanna ecosystems worldwide, many restoration efforts are underway. For savannas degraded by fire suppression and hardwood invasion, a first step towards restoration typically involves removal of unwanted trees and shrubs, but after invasive nonnative woody plants are top-killed, savanna restoration is often impeded by their resprouts. To evaluate patterns of vegetative recovery following clear-cuts and to explore their implications for ecosystem restoration, we determined the origins of the vegetation that develops after a clear-cut in hardwood-invaded sites being restored to pine savanna in Florida. We excavated stumps and other sprout sources, characterized the soil seed bank, and estimated seed production by early-to-mature species during the first growing season after treatment. In twenty 100-m2 plots, there was approximately one source of woody plant sprouts per square meter. Root sprouts were more abundant than sprouted stumps, and most of the stumps that did sprout were small (<10 cm diameter). Plants that emerged from seeds were only abundant in a previously disturbed area where Vitis rotundifolia Michx. seedlings were common. The soil seed bank was dominated by herbaceous ruderal species. During the first year after the hardwood clear-cut, seed production was dominated by the ruderal Phytolacca americana L. and the short-lived shrub Callicarpa americana L. Hardwood removal is a reasonable first step towards savanna restoration, but managers should be aware that the removal of invasive nonnative woody species will not shift the restoration sites toward savanna if needle-shedding pines and ground layer species that carry fire are not abundant.