Studies in grasslands have shown that autumn burning, or in the case of tropical areas, burning several months in advance of the rainy season, results in lower postfire productivity than spring burning. Autumn burning in Kansas tallgrass prairie caused greater postfire productivity than spring burning. This result is consistent with the hypothesis that warmer spring soil temperatures stimulate growth of the grasses. Spring and autumn burned plots had similar microclimates. It is possible that different results obtained in similar ecosystems are due to the influence of grazing, properties of different soils and soil decomposer communities, and different prefire nutrient status