Browsing by Subject "Fire ecology"
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Item Burn severity and tree species impacts on soil chemical and biological properties from fire-prone sites in the Davis Mountains, TX(2013-08) Dathe, Josefine; Moore-Kucera, Jennifer; Schwilk, Dylan W.; Perry, GadSoil is the basis of ecosystem functioning and health because of the numerous services it provides. It is a media for plant growth and habitat for animals and microorganisms. It stores, releases and cycles nutrients and atmospheric gases, regulates the storage, flow and purity of water, and also buffers wastes and toxins. Ecosystem disturbances such as wildfires can impact soil functioning by altering decomposition of soil organic matter (SOM) and nutrient transformation processes that are crucial for restoration following a disturbance. In arid and semi-arid ecosystems, high temperatures and low moisture availability limits plant growth and nutrient cycling. In these regions, fire is a critical component of the ecosystem that can enhance nutrient availability via the combustion of organic matter and vegetation. Fire not only influences aboveground composition and function but it also affects belowground processes which are important factors of ecosystem restoration, productivity and sustainability following a fire. In this study I investigated the impact of a wildfire that occurred in April 2012 in the Davis Mountains, Texas on soil chemical and biological properties important for nutrient cycling and ecosystem restoration. Soil samples (0-5 cm) were collected in June and October 2012 under three tree species (Quercus grisea (QUGR), Juniperus deppeana (JUDE) and Pinus cembroides (PICE)) and across three fire severity levels (unburned, low burn severity and high burn severity). Samples were analyzed for soil moisture, soil pH, inorganic nitrogen, SOM, soil microbial biomass (SMB), and soil enzymes (β-glucosidase, β-glucosaminidase and L-asparaginase). I hypothesized that fire will affect soil properties under QUGR (broad-leaved tree) differently compared to JUDE and PICE (coniferous trees) due to initial differences in those soil properties given that litter quality and inputs as well as microbial associations vary by tree species and influence physical, chemical and biological soil conditions. Furthermore, I hypothesized that fire will (1) reduce SOM, SMB and soil enzyme activity, and (2) increase soil moisture by removing vegetation cover, and soil pH and inorganic nitrogen (N) due to nutrient release upon SOM combustion and ash deposition. Results showed that tree species did not predominantly influence soil properties, with the exception of soil pH which was higher in QUGR and JUDE samples than in PICE samples. In June samples, burn severity affected soil pH, inorganic N, SOM content and soil enzyme activity with marked effects in high severity burns. Soil pH and NH4+-N concentrations increased while NO3--N, SOM content and enzyme activity decreased. In October samples, burn severity affected soil moisture content, soil pH, inorganic N, soil microbial biomass, and β-glucosidase and L-asparaginase activity with marked effects in high severity burns. Soil moisture content, soil microbial biomass and enzyme activity decreased while soil pH and inorganic N concentrations increased. Time since fire also affected soil properties and led to decreasing NH4+-N concentrations, SOM content and β-glucosidase and L-asparaginase activity while soil moisture content, NO3--N concentrations and soil microbial biomass N increased.Item Correlation of weather and other variables to mesquite damage by fire(Texas Tech University, 1970-05) Britton, Carlton M.Not availableItem Ecological role and potential use of fire in redberry juniper-mixed grass habitats(Texas Tech University, 1982-05) Steuter, Allen ANot availableItem Effects of Fire on an Ashe Juniper Community(Texas Tech University, 1972-05) Wink, Robert LynnNot Available.Item Effects of summer burning on Texas High Plains vegetation(Texas Tech University, 1997-05) Stanley, Charles R.The objectives of this study were to examine the effects of summer and winter prescribed fires on honey mesquite and broom snakeweed {Gutierrezia sarothrae (Pursh.)), as well as herbaceous vegetation. Sprouting response and mortality of mesquite were measured. Also, density of broom snakeweed was determined after 1 and 2 growing seasons. In addition, litter reduction, grass and forb yields were measured for 1 and 2 growing seasons following treatments. This study also recorded rate of fire spread on selected plots within each burn treatment to aid in determining safe burning parameters during summer fires.Item Fire effects on Matagorda Island vegetation(Texas Tech University, 1995) Brown, Steven Delmas; Wester, David B.; Allen, Bonnie L.Not availableItem Fire effects on small mammals and vegetation of the Northern Chihuahuan Desert(Texas Tech University, 1997-12) Monasmith, Tony JohnThe role of fire in the Northern Chihuahuan Desen has been of great interest and also heavily debated for 40 years. However, few replicated studies have documented the changes brought about by fire. .My study documented the short term effects of fire on a creosotebush (Larrea tridentata) dominated community and associated small mammal community. Prescribed burns were ignited during 13-15 June 1995 on 10 pairs (10 bumed. 10 unbumed) of 25- ha study sites. The 1995 bums reduced shmb (P = '» 006) and grass (P < 0.000) canopy cover to 64 and 16% of the preburn cover, respectively Complete recovery' of the canopy cover had not taken place 1 year post bum Densities of shrubs, primarily creosotebush. tarbush (Flourencia cemua). and cacti species (Opuntia) were reduced 1 year post bum. Mortality of creosotebush (25.6%) was lower than previously reported for summer burns. Tarbush monality (26 3°o) was similar to creosotebush on the study sites. Above average precipitation during June and July 1996 and lower competition by shmbs for available resources promoted an 1160% increase in forb canopy cover on the bumed sites.Item Fire effects on weeping lovegrass developmental morphology and forage quality(Texas Tech University, 1999-05) McFarland, James BrentWeeping lovegrass [Eragrostis curvula (Schrad.) Nees.] is an introduced perennial, warm-season, bunchgrass that is productive on a wide variety of soils, particularly sandy and sandy loam soils. Consequently, weeping lovegrass was widely used during the Conservation Reserve Program (CRP) on the Southem High Plains of Texas. Due to mismanagement, many producers have rejected weeping lovegrass as part of their grazing program. Management practices may be better implemented with an understanding of the morphological development of weeping lovegrass. Prescribed burning is a practical and efficient management tool to increase forage production and forage quality in weeping lovegrass. Understanding the impacts of fire on weeping lovegrass developmental morphology and forage quality may allow for better utilization in grazing systems. The objectives of this study were to: (1) quantify the developmental morphology of weeping lovegrass, (2) determine the effect of fire on weeping lovegrass developmental morphology, (3) determine the effect of fire on weeping lovegrass tiller demographics, and (4) determine the effect of fire on weeping lovegrass forage quality.Item Prescription development for burning two volatile fuel types(Texas Tech University, 2003-05) Racher, Brent J.Prescribed burning is used to manipulate vegetation worldwide. However, the practice carries an inherent danger because fires can escape and/or harm people. These studies were initiated to evaluate fire behavior and firebrand spotting potential for two volatile fuel types in which prescribed burning is being used. The first fuel type was saltcedar. Saltcedar stands carried crown fires and exhibited erratic fire behavior if they had not been burned before. Saltcedar that had been burned recently carried a fire through the fine, surface fuels. Differences in fire behavior occurred when saltcedar were burned at different phenologic stages. Spotting potential of firebrands from saltcedar fires was found up to 152 m and 163 m downwind for areas that had and had not been burned recently, respectively. The second fuel type was juniper/oak communities in Texas. Historically, prescriptions for burning during the late winter/early spring have been used. Recently, burning at higher temperatures mostly during the summer is becoming popular in this region. Behavior of some these fires exhibited alarmingly high rates of spread. Surprisingly, firebrands for many fires in this fuel type often were absent. However, firebrands were collected 152 m downwind from headfires. The volatility and conditions under which both of these communities have been and are being burned require that fire managers monitor more information than we have in the past. Variables such as 10-hr timelag fuel moisture, live fuel moisture, and the ability of personnel to perform under strenuous conditions need to be considered. Additionally, for these fuel types, installation of blacklines downwind of the fire at least 152 m and up to 213 m wide is critical to minimize the spotting potential from prescribed fires.Item Threshold requirements for burning downed honey mesquite(Texas Tech University, 1984-08) McPherson, Guy RForty-one headfires were burned in west Texas in the spring of 1984. Environmental and fine fuel characteristics (independent variables) were described prior to burning. Discriminant analysis was used to compare ignition and sustained combustion of 1,260 mesquite stems to independent variables. Multiple regression analysis was used to regress percent consumption of mesquite debris against independent variables. Critical variables for predicting ignition and sustained combustion were windspeed, stem moisture content, stem diameter, and proportion of green fuel in the fuel bed. Threshold values for ignition occurred at 6 km/hr windspeed, 6% surface stem moisture content, 5 cm stem diameter, and 15% green:total fine fuel. Threshold values for sustained combustion occurred at 15 km/hr windspeed, 6 cm stem diameter, and 6% stem moisture content at 1.25 cm below the stem surface. A predictive model for percent consumption of mesquite debris was developed. Windspeed and fine fuel moisture content accounted for 59% of the variability. A prescription for burning downed honey mesquite was developed.Item Threshold requirements for fire spread in grassland fuels(Texas Tech University, 1983-12) Clark, Robert GNot available