Effects of late growing-season and late dormant-season prescribed fire on herbaceous vegetation in restored pine-grassland communities

1998 ◽  
Vol 9 (1) ◽  
pp. 133-142 ◽  
Author(s):  
Jeffrey C. Sparks ◽  
Ronald E. Masters ◽  
David M. Engle ◽  
Michael W. Palmer ◽  
George A. Bukenhofer
Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Matthew C. Vaughan ◽  
Donald L. Hagan ◽  
William C. Bridges ◽  
Matthew B. Dickinson ◽  
T. Adam Coates

Abstract Background Despite the widespread use of prescribed fire throughout much of the southeastern USA, temporal considerations of fire behavior and its effects often remain unclear. Opportunities to burn within prescriptive meteorological windows vary seasonally and along biogeographical gradients, particularly in mountainous terrain where topography can alter fire behavior. Managers often seek to expand the number of burn days available to accomplish their management objectives, such as hazardous fuel reduction, control of less desired vegetation, and wildlife habitat establishment and maintenance. For this study, we compared prescribed burns conducted in the dormant and early growing seasons in the southern Appalachian Mountains to evaluate how burn outcomes may be affected by environmental factors related to season of burn. The early growing season was defined as the narrow phenological window between bud break and full leaf-out. Proportion of plot area burned, surface fuel consumption, and time-integrated thermocouple heating were quantified and evaluated to determine potential relationships with fuel moisture and topographic and meteorological variables. Results Our results suggested that both time-integrated thermocouple heating and its variability were greater in early growing season burns than in dormant season burns. These differences were noted even though fuel consumption did not vary by season of burn. The variability of litter consumption and woody fuelbed height reduction were greater in dormant season burns than in early growing season burns. Warmer air temperatures and lower fuel moisture, interacting with topography, likely contributed to these seasonal differences and resulted in more burn coverage in early growing season burns than in dormant season burns. Conclusions Dormant season and early growing season burns in southern Appalachian forests consumed similar amounts of fuel where fire spread. Notwithstanding, warmer conditions in early growing season burns are likely to result in fire spread to parts of the landscape left unburnt in dormant season burns. We conclude that early growing season burns may offer a viable option for furthering the pace and scale of prescribed fire to achieve management objectives.


Forests ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 423 ◽  
Author(s):  
Andrew Whelan ◽  
Seth Bigelow ◽  
Mary Nieminen ◽  
Steven Jack

Seasonal timing of prescribed fire and alterations to the structure and composition of fuels in savannas and woodlands can release understory hardwoods, potentially resulting in a global increase of closed-canopy forest and a loss of biodiversity. We hypothesized that growing-season fire, high overstory density, and wiregrass presence in longleaf pine woodlands would reduce the number and stature of understory hardwoods, and that because evergreen hardwoods retain live leaves, dormant-season fire would reduce performance and survival of evergreen more than deciduous hardwoods. Understory hardwood survival and height were monitored over seven years in longleaf pine woodlands in southwest Georgia with a range of overstory density, groundcover composition, and season of application of prescribed fire. Hardwood stem survival decreased with increasing overstory density, and deciduous hardwoods were more abundant in the absence of wiregrass. Contrary to expectations, evergreen hardwood growth increased following dormant-season fire. Differences in hardwood stem survival and height suggest that low fire intensity in areas with low overstory density increase the risk that hardwoods will grow out of the understory. These results indicate a need for focused research into the effects of groundcover composition on hardwood stem dynamics and emphasize that adequate overstory density is important in longleaf ecosystem management.


Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Marcelo H. Jorge ◽  
Sara E. Sweeten ◽  
Michael C. True ◽  
Samuel R. Freeze ◽  
Michael J. Cherry ◽  
...  

Abstract Background Understanding the effects of disturbance events, land cover, and weather on wildlife activity is fundamental to wildlife management. Currently, in North America, bats are of high conservation concern due to white-nose syndrome and wind-energy development impact, but the role of fire as a potential additional stressor has received less focus. Although limited, the vast majority of research on bats and fire in the southeastern United States has been conducted during the growing season, thereby creating data gaps for bats in the region relative to overwintering conditions, particularly for non-hibernating species. The longleaf pine (Pinus palustris Mill.) ecosystem is an archetypal fire-mediated ecosystem that has been the focus of landscape-level restoration in the Southeast. Although historically fires predominately occurred during the growing season in these systems, dormant-season fire is more widely utilized for easier application and control as a means of habitat management in the region. To assess the impacts of fire and environmental factors on bat activity on Camp Blanding Joint Training Center (CB) in northern Florida, USA, we deployed 34 acoustic detectors across CB and recorded data from 26 February to 3 April 2019, and from 10 December 2019 to 14 January 2020. Results We identified eight bat species native to the region as present at CB. Bat activity was related to the proximity of mesic habitats as well as the presence of pine or deciduous forest types, depending on species morphology (i.e., body size, wing-loading, and echolocation call frequency). Activity for all bat species was influenced positively by either time since fire or mean fire return interval. Conclusion Overall, our results suggested that fire use provides a diverse landscape pattern at CB that maintains mesic, deciduous habitat within the larger pine forest matrix, thereby supporting the diverse bat community at CB during the dormant season and early spring.


Forests ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 95
Author(s):  
Yuan Gong ◽  
Christina L. Staudhammer ◽  
Susanne Wiesner ◽  
Gregory Starr ◽  
Yinlong Zhang

Understanding plant phenological change is of great concern in the context of global climate change. Phenological models can aid in understanding and predicting growing season changes and can be parameterized with gross primary production (GPP) estimated using the eddy covariance (EC) technique. This study used nine years of EC-derived GPP data from three mature subtropical longleaf pine forests in the southeastern United States with differing soil water holding capacity in combination with site-specific micrometeorological data to parameterize a photosynthesis-based phenological model. We evaluated how weather conditions and prescribed fire led to variation in the ecosystem phenological processes. The results suggest that soil water availability had an effect on phenology, and greater soil water availability was associated with a longer growing season (LOS). We also observed that prescribed fire, a common forest management activity in the region, had a limited impact on phenological processes. Dormant season fire had no significant effect on phenological processes by site, but we observed differences in the start of the growing season (SOS) between fire and non-fire years. Fire delayed SOS by 10 d ± 5 d (SE), and this effect was greater with higher soil water availability, extending SOS by 18 d on average. Fire was also associated with increased sensitivity of spring phenology to radiation and air temperature. We found that interannual climate change and periodic weather anomalies (flood, short-term drought, and long-term drought), controlled annual ecosystem phenological processes more than prescribed fire. When water availability increased following short-term summer drought, the growing season was extended. With future climate change, subtropical areas of the Southeastern US are expected to experience more frequent short-term droughts, which could shorten the region’s growing season and lead to a reduction in the longleaf pine ecosystem’s carbon sequestration capacity.


2015 ◽  
Vol 8 (1) ◽  
pp. 15-31 ◽  
Author(s):  
Jonathan R. King ◽  
Andrew J. Bennett ◽  
Warren C. Conway ◽  
David J. Rosen ◽  
Brian P. Oswald

AbstractIntroduced accidentally from South America, deeproot sedge is rapidly expanding in a variety of habitats throughout the southeastern United States. Of particular concern is its rapid expansion, naturalization, and formation of monocultures in Texas coastal prairie, one of the most imperiled temperate ecoregions in North America. The objective of this research was to examine how deeproot sedge responds to prescribed fire, to the herbicide imazapic, and to treatment combinations of both. Combinations of prescribed fire and imazapic treatments and imazapic-only treatments effectively reduced deeproot sedge cover and frequency. However, plots exposed to dormant season fires (with no imazapic) had greater deeproot sedge cover after burn treatments were applied, indicating that coastal prairie management using only dormant season prescribed fire will not work toward reduction or management of this exotic invasive species. Although deeproot sedge cover was often reduced in fire–imazapic treatment combinations, it was still present in treatment plots. Moreover, desirable functional plant groups (i.e., native bunchgrasses) did not respond positively to the fire–imazapic treatments, but in some instances, woody plant coverage increased. Repeated, long-term approaches using integrated and coordinated efforts with multiple treatment options will be necessary to restore community structure to desired compositional levels. Such integrated approaches should be effective in reducing deeproot sedge frequency, cover, and extent to more manageable levels throughout its introduced geographic range.


2016 ◽  
Vol 25 (6) ◽  
pp. 657 ◽  
Author(s):  
Erik S. Krueger ◽  
Tyson E. Ochsner ◽  
J. D. Carlson ◽  
David M. Engle ◽  
Dirac Twidwell ◽  
...  

Measured soil moisture data may improve wildfire probability assessments because soil moisture is physically linked to fuel production and live fuel moisture, yet models characterising soil moisture–wildfire relationships have not been developed. We therefore described the relationships between measured soil moisture (concurrent and antecedent), as fraction of available water capacity (FAW), and large (≥405 ha) wildfire occurrence during the growing (May–October) and dormant (November–April) seasons from 2000 to 2012 in Oklahoma, USA. Wildfires were predominantly grass and brush fires but occurred across multiple fuel types including forests. Below-average FAW coincided with high wildfire occurrence each season. Wildfire probability during the growing season was 0.18 when concurrent FAW was 0.5 (a threshold for plant water stress) but was 0.60 when concurrent FAW was 0.2 (extreme drought). Dormant season wildfire probability was influenced not only by concurrent but also by antecedent FAW. Dormant season wildfire probability was 0.29 and 0.09 when FAW during the previous growing season was 0.9 (near ideal for plant growth) and 0.2, respectively. Therefore, although a wet growing season coincided with reduced wildfire probability that season, it also coincided with increased wildfire probability the following dormant season, suggesting that the mechanisms by which soil moisture influences wildfire probability are seasonally dependent.


Fire ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 25 ◽  
Author(s):  
David G. Ray ◽  
Deborah Landau

This case study documents the aftermath of a mixed-severity prescribed fire conducted during the growing season in a young loblolly pine forest. The specific management objective involved killing a substantial proportion of the overstory trees and creating an open-canopy habitat. The burn generated canopy openings across 26% of the 25-ha burn block, substantially altering the horizontal structure. Mortality of pines was high and stems throughout the size distribution were impacted; stem density was reduced by 60% and basal area and aboveground biomass (AGB) by ~30% at the end of the first growing season. A nonlinear regression model fit to plot data portrays a positive relationship between high stocking (i.e., relative density > 0.60) and postburn mortality. Survival of individual trees was reliably modeled with logistic regression, including variables describing the relative reduction in the size of tree crowns following the burn. Total AGB recovered rapidly, on average exceeding levels at the time of the burn by 23% after six growing seasons. Intentional mixed-severity burning effectively created persistent canopy openings in a young fire-tolerant precommercial-sized pine forest, meeting our objectives of structural alteration for habitat restoration.


1992 ◽  
Vol 22 (8) ◽  
pp. 1179-1183 ◽  
Author(s):  
James W. McMinn

Oak–pine stands in the Upper Piedmont of Georgia were whole-tree harvested to 10- and 2.5-cm DBH limits in both the dormant and early growing season, then allowed to regenerate spontaneously with no further perturbations. After 10 years, stands harvested in the early growing season exhibited higher diversity than those harvested in the dormant season. After the dormant-season harvests, 10-cm-limit stands tended to be more diverse than 2.5-cm-limit stands. The harvest disturbance primarily affected evenness, rather than species richness.


1984 ◽  
Vol 14 (6) ◽  
pp. 950-952 ◽  
Author(s):  
K. T. Smith ◽  
R. O. Blanchard ◽  
W. C. Shortle

Cambial electrical resistance (CER) was related to the number of cells per radial file of vascular cambium in dominant and codominant balsam fir (Abiesbalsamea (L.) Mill.) trees sampled during the growing season. Scanning electron microscopy (SEM) was used to examine the vascular cambial zone (VCZ) of balsam fir during the growing and dormant seasons. Trees selected for SEM were categorized as having growing season CER < 10 kΩ or CER > 12 kΩ. The two growing trees with CER < 10 kΩ had a mean of seven cells per radial file of VCZ in contrast with four cells per radial file in the two trees of CER > 12 kΩ. Trees of either growing season category had dormant season CER > 12 kΩ and four cells per radial file of VCZ. The relationship between CER and the number of cells per radial file of VCZ supports the hypothesis relating CER to periodic growth rate in balsam fir.


2002 ◽  
Vol 6 (3) ◽  
pp. 351-362 ◽  
Author(s):  
Ø. Kaste ◽  
B. L. Skjelkvåle

Abstract. Effects of contrasting climatic conditions and nitrogen (N) deposition levels on streamwater N dynamics are assessed at two small heathland catchments; Dalelva in northern Norway (69°N) and Øygard in southwestern Norway (58°N). The study comprises 11 years of data on climate, hydrology and N inputs/outputs from Dalelva and 8 years of corresponding data from Øygard. Both sites are comparable in catchment size, geology and land cover characteristics, but have large differences in climate and N deposition. Dalelva is characterised by a cold, arctic climate and low N deposition (2-3 kg N ha–1y–1), whereas the Øygard site has a more mild, humid climate with much larger N deposition (13–19 kg N ha–1yr–1). Streamwater nitrate (NO3‾) concentrations at Dalelva generally were negligible during the growing season, but showed a steady increase during the dormant season until a maximum of 40-100 μg N L–1 was reached just before snowmelt. At onset of the snowmelt flood, NO3‾ concentrations decreased momentarily to very low levels, suggesting that N eluted from the seasonal snowpack to a great extent was infiltrated and immobilised in the soils. At Øygard, flood peaks occurred frequently during all seasons, and usually there was no distinct spring flood. A lack of clear dilution effects from floods on streamwater N3‾ concentrations may indicate a relatively high NO3‾ leaching potential in this catchment. On average, the annual NO3– export was negligible at Dalelva (<0.1 kg N ha–1yr–1), while at Øygard it amounted to 3.0±0.3 (±1 s.d.) kg ha–1yr–1, or nearly 20% of the annual N deposition. In addition to this relatively high annual N loss, elevated NO3‾ concentrations during the growing season further indicate that the N supply at Øygard is in excess of the combined plant and microbial demand. Keywords: catchments, surface water, nitrogen deposition, nitrate leaching, climate, hydrology, snowmelt, Dalelva brook, Øygard brook


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