A New Picture of Fire Extent, Variability, and Drought Interaction in Prescribed Fire Landscapes: Insights From Florida Government Records.

Florida, United States, government records provide a new resource for studying fire in landscapes managed with prescribed fire. In Florida, most fire area (92%) is prescribed. Current satellite fire products, which underpin most air pollution emission inventories, detect only 25% of burned area, which alters airborne emissions and environmental impacts. Moreover, these satellite products can misdiagnose spatiotemporal variability of fires. Overall fire area in Florida decreases during drought conditions as prescribed fires are avoided, but satellite data do not reflect this pattern. This pattern is consistent with prescribed fire successfully reducing overall fire risk and damages. Human management of prescribed fires and fuels can, therefore, break the conventional link between drought and wildfire and play an important role in mitigating rising fire risk in a changing climate. These results likely apply in other regions of the world with similar fire regimes.

Legumes native to longleaf pine savannas exhibit capacity for high N2 -fixation rates and negligible impacts due to timing of fire.

• N2 fixation rates of three legume species and the impact of fire regime are reported. • Summer, winter, and no burn treatments were applied. N 2 fixation rates ( 15 N isotope dilution) and C trade-offs with flowering and fine root turnover were examined in response to season of burn. • Tephrosia and Centrosema had uniformly high percentage N dfa across all treatments (74-92% N dfa ), whereas Rhynchosia showed limited N 2 fixation activity (18% and 0%). No evidence for decreased N 2 fixation due to loss of leaf area following growing season burns was found. Moreover, no consistent evidence for decreased N 2 fixation with greater flowering or fine root turnover was observed. • Despite species differences in response to fire regime, the following patterns emerged: when increased N 2 fixation is associated with decreased growth rates, legumes show limited N 2 fixation rates (as seen in Rhynchosia ). Alternatively, if greater N 2 fixation is related to increased growth rates, then legumes experience C limitations to N 2 fixation only in small individuals or during periods of rapid growth (as in Centrosema ). Reproduction may influence N 2 -fixation, but, as in the case of Tephrosia , the relationship was positive, opposite to patterns indicative of C trade-offs.