Growing-season Burns Research Articles

Fire and the dynamics of a semi-arid grassland: influence on soil characteristics

The short-term impact of fire burning with the wind (head fire) and against the wind (back fire) on soil characteristics (soil-water content, soil compaction, soil temperature, organic matter, pH, exchangeable Ca, Mg, K, Na and extractable P) were determined in a semi-arid grassland. This study was conducted over two growing seasons (2000/01 and 2001/02) after only one burning treatment in August 2000. The back fire moved approximately 7.5 times slower than the head fire, leading to the greatest change in hydrological characteristics. The decline in plant cover due to the fire resulted in a considerable increase in soil compaction, soil temperature and a decrease in organic material in turn leading to a lowered soil-water content. Much of the influence of these variables had not been completely reduced two growing seasons after the fire. Burning reduced the soil-water content (0mm to 300mm soil depth) after one month and one year by 13.4% and 31% respectively. Temporary wilting for all grass species occurred more rapidly with burning. During March of the first year, the greatest soil temperature difference (50mm depth) occurred between burnt and unburnt grassland, with the highest soil temperatures recorded in January. The highest temperature on the surface of the soil for each year after burning also occurred during January. Over the first growing season burning significantly reduced organic carbon (C) and total nitrogen (N) content and extractable phosphate, but increased the pH and concentration of exchangeable Ca, Mg, Na and K in the soil, over the first 0–50mm layer. There were no differences in the soil properties of head and back fires, except for organic material that was further lowered by the back fire. With depth, organic matter and K decreased significantly and Ca increased between surface (0mm to 50mm) and lower (50mm to 100mm) layers due to burning. Thus, an unplanned event can increase the intensity and frequency of seasonal droughts in the ecologically sensitive semi-arid grassland areas leading to increase risk management in the short-term.

Burrow Abandonment by Gopher Tortoises in Slash Pine Plantations of the Conecuh National Forest

We investigated burrow dynamics and factors associated with abandonment of burrows hy gopher tortoises (Copherus polyphemus) in mature slash pine (Pinus elliottii) plantations of the Conecuh National Forest (CNF) in southcentral Alabama. Our objectives were to determine how frequently gopher tortoises abandoned burrows in pine plantations, if burrow abandonment was associated with changes in vegetation conditions, and how rapidly these changes occurred. Burrow survey data collected over 5 years indicated gopher tortoises abandoned burrows at an average rate of 22%/year. We believe burrow abandonment occurred frequently in pine plantations, primarily in association with a change in overstory structure that shaded active burrows. Abandoned gopher tortoise burrows had greater total basal area (P = 0.012), hardwood basal area (P = 0.016), and tree density (P = 0.003) than did active burrows. There was a significant positive correlation between age of active gopher tortoise burrows and canopy closure (total basal area: r 2 = 0.19, P = 0.007; pine basal area: r 2 = 0.20, P = 0.004; tree density: r 2 = 0.14, P = 0.018). We estimated that overstory conditions at newly active burrows changed to those observed at abandoned burrows in only 5-7 years. Increases in total basal area to 70 m 2 /ha and tree density to 1,400 trees/ha were associated with burrow abandonment. Active burrows had greater total plant cover (P = 0.009) and grass cover (P = 0.016) than did abandoned burrows. However, we found no correlation between age of active burrows and structure and composition of ground cover vegetation (r 2 values ranged from 0.00 to 0.07; P-values ranged from 0.096 to 0.987). Stand thinning to a basal area of 30 m 2 /ha and prescribed growing-season burns should improve habitat quality, thereby increasing burrow fidelity of gopher tortoises.

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

Wildfire in the growing season is relatively frequent and interest is increasing in using growing-season fire in management of tallgrass prairie. However, the influence of fire 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 to late growing-season fire at different frequencies. We applied 4 burning treatments (no burn, or 1, 2, or 3 burns in 5 years) in the late growing 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 (Aristida 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 (1,980 kg ha-1) than on plots that were not burned (1,290 kg ha-1) 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 in 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 perennial grasses increased to almost 40% of total production on twice-burned plots averaged across sites. Other than the effect on cool-season perennial grasses, 2 burns over a two-year period had little effect beyond the first growing season after the second burn. 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 fire 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 tallgrass prairies.

Alleviating conflicts between army training and endangered species at fort bragg

AbstractThe second‐largest endangered red‐cockaded woodpecker (Piciodes borealis) (RCW) population in the world is located in the Sandhills physiographic region of North Carolina. The majority of the RCWs are located on the Ft. Bragg Military Installation. Ft. Bragg is working toward species recovery by conducting intensive cavity enhancement, RCW tree monitoring, RCW breeding surveys, growing season burns, and midstory reduction. However, significant barriers to recovery exist. The RCWs occur in two smaller‐than‐viable populations, one primarily on Ft. Bragg and surrounding private lands, the other on Camp Mackall and the state‐owned Sandhills Game Lands. Camp Mackall is separted from Ft. Bragg by a 10‐kilometer gap of private and state landholdings. Cooperation among private, federal, and state landowners is necessary to reestablish and maintain habitat for linkage between the Camp Mackall and Ft. Bragg populations. Dispersal between populations is required to ensure genetic interchange, increase population stability, and fcilitate recovery of the Sandhills population. A regional working group consisting of personnel from federal, state, and private conservation organizations has been established to develop and coordinate a conservation strategy for the North Carolina Sandhills. Current initiatives include: (1) safe harbor habitat conservation plan; (2) public outreach programs; (3) cooperative research agreement between the Army and the National Biological Survey; and (4) cooperative agreement between the Army and The Nature Conservancy. The future of military training at Ft. Bragg is linked to recovering endangered species, precluding the need to list additional species as endangered, and sustaining the longleaf‐wiregrass ecosystem of the region.

Seed Production of Wiregrass in Central Florida Following Growing-Season Prescribed Burns

Wiregrass (Aristida stricta Michx.) is a major species in the long leaf pine (Pinus palustris Mill.) sandhills areas of central Florida, providing a major portion of the fuel for the recurring ground fires necessary to maintain the community. Growing season burning promotes flower and seed production. The objective of this study was to assess the seed production potential of wiregrass following prescribed burns from May through August. Four longleaf wiregrass sites were prescribed burned, one each in May, June, July, and August. Information on bunch size, bunch density, seed stalk density, seed density, and seed germination were collected. The four sites differed significantly in the density of wiregrass bunches, average bunch size, wiregrass cover and seed viability. The density of seed stalks was fairly consistent across sites. Viable seed production was lowest on the June burned site and highest on the July burned site. The study shows good quantities of seed are comparatively easy to produce with growing season bums.