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Changes in structural and compositional attributes of shinnery oak (Quercus havardii Rydb.) plant communities have occurred in the twentieth century. These changes may in part relate to altered fire regimes. Our objective was to document effects of prescribed fire in fall (October), winter (February), and spring (April) on plant composition. Three study sites were located in western Oklahoma; each contained 12, 60 × 30‐m plots that were designated, within site, to be seasonally burned, annually burned, or left unburned. Growing season canopy cover for herbaceous and woody species was estimated in 1997–1998 (post‐treatment). At one year post‐fire, burning in any season reduced shrub cover, and spring burns reduced cover most. Winter and annual fires increased cover of rhizomatous tallgrasses, whereas burning in any season decreased little bluestem cover. Perennial forbs increased with fall and winter fire. Shrub stem density increased with fire in any season. Communities returned rapidly to pre‐burn composition with increasing time since fire. Fire effects on herbaceous vegetation appear to be manifested through increases in bare ground and reduction of overstory shrub dominance. Prescribed fire can be used as a tool in restoration efforts to increase or maintain within and between community plant diversity. Our data suggest that some plant species may require or benefit from fire in specific seasons. Additional research is needed to determine the long‐term effects of repeated fire over time.

Natural fires on the native grasslands of Oklahoma and Kansas were important for maintaining ecosystem structure and function. Today, land managers largely conduct prescribed fires in the late dormant season or they do not burn at all. When wildfires occur in other seasons, conventional wisdom assumes that desirable forage species for cattle are compromised. This assumption is based on a few fire studies limited in breadth and scope. To address this, we revisited numerous data sets to quantify the influence of season of fire on plant production and species composition. Research demonstrates that tallgrass prairie burned in the late spring starts growth earlier, grows more rapidly early in the growing season, and produces more tall grasses than unburned prairie. We contrast this response with the literature reporting the results of fire occurring in other seasons. Fire effects vary with fire frequency, fire-return interval, grazing history, herbicide use, successional stage, weather pattern, edaphic features, and topography. Our review of research suggests that a variety of responses to fire season are possible and rules-of-thumb that generalize responses are misleading. Most of the research on fire also does not report the interaction of fire and herbivory. Thus it is difficult to judge the influence of fire within the context of herbivory. Results from ongoing research suggest that the prairie is far more resilient under the interaction of fire and herbivory than earlier believed.Key Words: native grasslands, prescribed fire, fire frequency, fire interactions, fire return interval, wildfire Fire on the native grasslands of Oklahoma and Kansas, as in other portions of the Great Plains, provided a portion of the energy required for the development and maintenance of these grasslands (Bragg 1995). Natural fire was possible from late in the growing season before the first killing freeze in autumn, through the dormant season (i.e., after the first freeze in autumn and before the last freeze in spring), and up to several weeks after the last freeze in spring (Bragg 1982, Higgins 1986. The timing of fires with respect to season or within a season potentially influences plant species composition and productivity, and therefore influences rangeland management in the modern landscape. In this paper we demonstrate that a variety of plant species composition and production responses to season of fire are possible, and that prairie is far more resilient to burning in any season than is accepted commonly by conventional wisdom.Prescribed fire for livestock management in the grasslands of Oklahoma and Kansas is usually intended to enhance forage quality for cattle. Fires conducted early in the freeze-free period of the spring, traditionally referred to as late spring, coincide with resumption of active growth of warm-season grasses following winter dormancy. Late spring burning has been recommended for optimum cattle production (Launchbaugh and Owensby 1978). Fires conducted in winter or early spring are intended to e...

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