PARENT SESSION
Wednesday, August 9, 5:00-6:30 pm
Poster Session 18 - Forest ecology and management
Exhibit Hall, Ballroom Level, Cook Convention Center
Do biennial prescribed fires in closed oak/hickory forests initiate savannah restoration.
Wait, D. Alexander*,1, Anderson, Wendy2, 1 Missouri State University, Springfield, MO2 Drury University, Springfield, MO
ABSTRACT- Highly periodic spring burns are used for the goal of restoring presumably historic savannah or woodland habitat that is currently closed forest. However, fire effects at various levels of ecological scale are rarely monitored simultaneously (i.e., population, community, and ecosystem). Here I report on changes in forest structure and ecosystem characteristics and processes after 3 biennial prescribed fires in a closed oak/hickory forest in the Ozarks of Missouri that had not burned for 50 years. Burning has decreased cedar sapling but not seedling density, and increased total oak seedling and sapling density; however, most oak recruits are probably root sprouts. Burning has had no effect on the species composition of overstory trees; however, burning has promoted dogwood over elm in the subcanopy. Folivory on oak saplings was 66% higher in burned areas compared to unburned areas, with 19% of oak sapling leaf area removed in burned areas compared to 9% in unburned areas. Burning has decreased overstory tree density by 40% resulting in a 46% increase in solar radiation at 1 m above the ground; as a consequence, carbon gain in oak and hickory saplings as measured by net assimilation rate has increased 50% in burned areas. Interestingly, overstory leaf expansion ceases in May in burned but July in unburned forest. Leaf litter and acorn mass were greater in burned areas than in unburned areas, but only in the first three years after burning was initiated. Soil respiration has been consistently greater in burned than unburned forest, while soil moisture, temperature, and nitrogen availability have not been significantly affected by burning. In summary, three prescribed burns over six years have clearly resulted in greater light in the understory; however, only a few changes in species composition or ecosystem characteristics and processes are consistent with those typically found in savannah habitats.
Key words: oak/hickory forest ecosystems, prescribed fire, restoration ecology