Monday, 17 November 2003: 3:30 PM
Responses of long-unburned scrub on the Merritt Island/Cape Canaveral barrier island complex to cutting and burningPoster PDF (147.7 kB)
Restoration of long-unburned scrub on the Merritt Island/Cape Canaveral complex has been underway since 1992. Florida scrub ecosystems are shrublands maintained by relatively frequent fire. With fire suppression and landscape fragmentation, some scrub has reached a size structure resistant to fire under typical prescribed burning conditions. Without burning, the habitat suitability of scrub for a variety of species declines. We obtained pretreatment data from 186 permanent 15 m line-intercept transects in 29 stands across the barrier island complex. On acid soils (e.g., Paola, Pomello, Astatula, Orsino, and Immokalee series) (11 stands) oak-saw palmetto scrub occurred with Quercus myrtifolia, Q. geminata, Q. chapmanii, Serenoa repens, and Lyonia ferruginea as the dominant species. On less acid to circumneutral soils, (Cocoa, Welaka series) oak-saw palmetto scrub (6 stands) occurred although with ericads less abundant. On younger, alkaline soils (Canaveral, Palm Beach series), community composition changed to coastal scrub (12 stands) with a shrub form of Quercus virginiana as the dominant oak and Q. geminata, Q. chapmanii, and ericads absent. Quercus myrtifolia occurred in transitional areas, but Serenoa remained abundant. Myrcianthes fragrans and Persea borbonia increased in abundance in coastal areas. Mean height of unburned stands ranged from 1.5 - 7.5 m; height differences reflected different periods of fire suppression and probably different growing conditions. Mechanical treatments have included rotary cutters (Brown, Hydroax), K-G and V blades, tree-topper, and roller-chopper. Sites were prescribed burned after cutting. Fires were most effective if conducted within ca. 6 months of cutting. We obtained post-burn data on 147 transects in 23 stands by sampling at least annually. Regeneration on all sites was primarily by sprouting of woody species. Increases in weedy herbaceous species were small and transitory. In oak-saw palmetto scrub, recovery of oaks and ericads was similar in cut/burned stands to scrub burned without cutting. Saw palmetto cover was reduced by all mechanical treatments compared to burning only and that reduction persisted. Height growth in cut/burned scrub often exceeded growth of scrub burned without cutting. The dominant species in coastal scrub also sprouted after cutting and burning. Height growth of Q. virginina usually exceeded growth rates of other oaks. Invasion by the exotic Brazilian pepper (Schinus terebinthifolius) occurred in some coastal scrub on alkaline soils. Combinations of mechanical treatment and prescribed burning can be effective in restoring long-unburned scrub. Mechanical treatment must be used with care to avoid soil disturbance and excessive loss of saw palmetto, the most flammable component of the system.