Late Growing-Season Fire Effects in Mid-Successional Tallgrass Prairies

Abstract

Wildfire in the growing season is relatively frequent and interest is increasing in using growing-season fm in management of tallgrass prairie. However, the influence of fue in the growing season on forage production and species composition, especially in mid-successional tallgrass prairie, is largely unknown. Our objective was to compare vegetation composition and production on Loamy Prairie and Very Shallow ecological sites in mid-successional stages in response tu late growing-season fire at different frequencies. We applied 4 burning treatments (no burn, or 1, 2, or 3 burns iu 5 years) in the late growhtg season in southern Oklahoma during a series of years of above-average precipitation. The sites were dominated at the beginning of the study by early-and mid-successional species including prairie threeawn (Aristi oligantha (Michx)), a species indicating a disturbance history. After the initial burns in 1990, tallgrasses, little bluestem, and perennial grasses were reduced by burning on the Loamy site. Forbs were more productive on burned plots (1,9&t kg ha-') than on plots that were not burned (1,290 kg ha") averaged across sites. Total production was not reduced by burning in 1990. Growing-season burns in 2 consecutive years had little influence on species composition or production as compared to a single burn ht 2 years. Warm-season perennial grasses other than tallgrasses and little bluestem increased on the Loamy site, but decreased on the Shallow site. Production of cool-season perenuial grasses increased to almost 49% of total production on twiceburned plots averaged across sites. Other than the effect on coolseason perennial grasses, 2 burns over a two-year period bad little effect beyond the fmt growing season after the second bum. Twice-burned plots and plots burned 3 times produced more forbs than either plots that were burned once or not burned. Production of perennial grasses was opposite that of forb production. Total production was not reduced on either site regardless of fw frequency. Results indicate managers may expect a short-term reduction in production of forage grasses and an increase in forbs following late growing-season fire in mid-successional Mlgrass prairies,

Texas Wintergrass and Buffalograss Response to Seasonal Fires and Clipping

“…plants m À2 ) in July 1994 after winter or summer fires in 1991, 1992, and 1993 in south Texas, but it was not determined whether this was a significant difference. Engle et al (1998) found that a latesummer fire decreased C 3 grass (primarily Texas wintergrass) production for up to 3 years post-fire on a loamy site in Oklahoma. However, on a very shallow site, Texas wintergrass response was similar to our study: production decreased the first year post-fire, but increased over the no fire treatment by 3 years post-fire.…”

Sideoats Grama Growth Responses to Seasonal Fires and Clipping

“…Several studies of summer fire in the Tallgrass Prairie of the United States found a decline in C 4 grass production during the first year after a summer fire but also found a recovery to preburn or unburned control levels by the second or third year (Engle et al 1998;Engle and Bidwell 2001). The slower recovery of sideoats grama at our mixed-grass prairie site following summer fire, compared with what is typically found in the Tallgrass Prairie (Engle and Bidwell 2001), is likely due to the greater aridity and variability in precipitation events at our study site compared with Tallgrass Prairie sites.…”

Short-Term Responses of Southern African Semi-Arid Rangelands to Fire: A Review of Impact on Plants

“…Depending on the climatic conditions, aboveground phytomass production of burned rangeland can normally take at least two growing seasons for full recovery (Table 1). According to Engle et al (1998), the growing-season burns in consecutive years had little influence on production as compared to a single burn in two years in the tall grass prairies (rainfall 750 to 900 mm) of south-central Oklahoma. The reason for these findings is unclear and need future in depth research.…”