Woodyard Hammock Study – 32nd Year
By Dr. Kevin Robertson, Fire Ecology Scientist
It is an even year and time to conduct the biennial census of the Woodyard Hammock long-term study of an old-growth beech-magnolia bottomland forest on Tall Timbers Research Station. All trees >2 cm diameter breast height (DBH) in a 4.5 hectare (11 acre) area have been censused every two years since being established by Dr. William Platt in 1978, providing a long data history on forest dynamics in the absence of fire.
In 1985, Hurricane Kate felled many trees and doubled the number of tree stems because of recruitment in light gaps. Since the hurricane, the increase in trees has mostly been two understory species, hophornbeam (Ostrya virginiana) and bluebeech (Carpinus caroliniana), to the exclusion of most canopy species. We hypothesized that infrequent fire during dry years might tip the balance of tree dominance by reducing these fire sensitive species and giving other species the chance to be recruited. In April 2006, we burned a total of half of the research plot in a checkerboard pattern and have been tracing responses in the vegetation since then. Although numbers of hophornbean and bluebeech began to decline prior to the fire, the rate of decrease was doubled in burned plots compared to unburned plots following the fire, and other species were not as strongly affected. This year's census will determine further trends to assess the impact of the burn, including effects on recruitment of other forest species.
This year's census is being conducted by interns Bailey Spitzner and Meredith Liedy, both of whom will be seniors at Florida State University this fall. In addition to conducting the Woodyard Hammock census, they have collected soil bulk density samples for the Stoddard Plot fire frequency study, assisted with prescribed burns and fire behavior measurements at Pebble Hill Plantation, and assisted with improvements to the herbarium database, among other duties.
Bailey Spitzner and Meredith Liedy measuring tree diameters in Woodyard Hammock.