Long-Term Stand Dynamics in a Pyrophytic Longleaf Pine Ecosystem
Hammond, Darcy Helen
AdvisorVarner, Julian Morgan
CommitteeKush, John S.
Fan, Zhaofei (Joseph)
Reference ecosystems are a valuable tool for restoration and management efforts in degraded ecosystems. Longleaf pine (Pinus palustris), a pyrophytic southeastern U.S. ecosystem, have declined precipitously in extent since European settlement. Pine mortality and growth patterns were examined in a 15-year re-measurement study in two old-growth stands. Both stands experienced post-fire mortality and short-lived decreases in basal area. Distance to nearest neighbor had a significant effect on mortality of small (<10 cm DBH) pine. To better approximate reference conditions, saplings of five co-occurring hardwood species were destructively measured for bark accumulation and taper using bark and wood thickness. Significant species differences were detected in bark:wood ratio (P<0.001), with no difference in wood diameter. Blackjack oak (Quercus marilandica) had a bark:wood ratio 3x the closest species and steeper slopes of bark accumulation, suggesting that it is a fire-adapted species. These results will inform reference conditions for critical regional pine restoration efforts.