Browsing by Author "Britton, Carlton M."
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Item An analysis of terrain roughness: Generating a GIS application for prescribed burning(2008-05) Crawford, Matthew Allan; Fish, Ernest B.; Britton, Carlton M.; Mulligan, KevinPrescribed burning is a technique used to rejuvenate pastures by enhancing wildlife habitat, brush control, and removing old growth. The technique has become a science and has been in practice for decades to model naturally occurring fire regimes. Planning a prescribed burn is a detailed and careful formula that requires a great deal of time and preparation. This study presents a procedure that will greatly reduce the amount of time and money spent in planning a burn. Fire lines are typically located along pasture fences for prescribed burning in Texas. In rough, hilly terrain this results in fire lines traversing steep slopes and deep canyons that greatly increase expense and pose hazardous conditions for personnel. By combining the power of technology with the knowledge of a burn expert, an innovative approach to fire line location may possibly be developed, using existing programs to build a model that predicts the smoothest and most suitable path for fire lines. In order to accomplish this task, several steps were taken. First, an application was found that provides the desired algorithm to calculate a roughness surface from a digital elevation model. The roughness surface is then classified by a newly suggested classification index. An application has been developed to use the roughness surface to obtain isoline locations for the burn area. The Rocker Ranch which is located on the edge of the Llano Estacado escarpment in Borden County, Texas provided an excellent area for testing the model. The fire lines are based on the isolines which represent the smoothest route, within the designated area. This application will optimize the fire line planning process for prescribed burning by saving time and money.Item Biophysical and human characteristics of wildfire ignition in the shortgrass prairie region of Texas(2012-12) Beierle, Micah John; Fish, Ernest B.; Rideout-Hanzak, Sandra; Wester, David B.; Britton, Carlton M.; Mulligan, Kevin; Schwilk, Dylan W.Human and biophysical variables which influence occurrence and seasonality of reported wildfires in the shortgrass prairie region of Texas are relatively undefined. Stepwise logistic regression was applied to Texas Fire Reporting system data within the shortgrass prairie region from 2001 to 2010 to assess the relative importance of human and biophysical factors. Wildfire seasonality was assessed by comparing months with respect to number and size of reported wildfires. Eighty-five percent of the total area that burned during the study period burned between January and June; January through March had the most reported wildfires; August through October had the fewest reported wildfires. Of the known reported wildfire causes, humans caused 79% of reported wildfires in the shortgrass prairie region of the Southern Great Plains in Texas. Of this 79%, three categories were most common. These three categories are equipment use-related reported wildfires (36%), debris burning (24%), and smoking (10%). Logistic regression indicated that the likelihood of wildfire ignition is spatially related to human population factors. Distances to a road and population change from 2000 to 2009 were the most important factors affecting reported wildfire occurrence. Understanding and public support for proper management of fuels in this fire-prone system is a necessity. This study has identified several important human components of reported wildfires that should be considered during roadside management as well as urban, suburban and rural planning.Item Burning season effect on four southern Chihuahuan desert plants(Texas Tech University, 2009-05) Luna, Miguel; Britton, Carlton M.Use of prescribed fire to manage undesirable vegetation in the Chihuahuan Desert of Mexico, promises acceptable results, but information on plants responses to different weather conditions and fuel load availabilities is lacking in Mexico. This study investigated the effect of three burning seasons with two fuel load simulations and two plants size on plant mortality and changes in basal area of four native species of southern Chihuahuan Desert. The study was conducted in the Mexican High Plateau in Jalisco, Mexico during two consecutive years, 2005 and 2006, in a shortgrass prairie of blue grama (Bouteloua gracilis) with problematical populations of broomweed (Isocoma venetus), brickellbush (Brickellia spinulosa) and broomgrass (Muhlembergia rigida). Fire environment was simulated using a portable propane burner calibrated to simulate time-temperature reached with 1,700 and 2,800 kg/ha fine fuel load. Size of plant was determined by height and canopy diameter in shrubs, and indicial area diameter in grasses. Shrubs with a minimum height of 25 cm and canopy diameter of 31 cm were classed as large plants. Grasses with a basal area diameter of 10 cm were classed as large plants. Plants with measurements less than these were placed in the small plant group. For each species, 50 plants were randomly treated each season at each fuel load and plant size. Plants were identified with numbered tags to evaluate mortality and basal area changes in subsequent growing season. As control, 50 plant of each species and size received no fire treatment. Plants with no live tillers one year after treatment were assumed to be dead. Basal area change was estimated based in number of pixels/cm2, using vertical photos and the Adobe Photoshop Software. Statistical analysis was performed with the GLM procedure in SAS. Mortality of blue grama plants was affected significantly by season of burning, fuel load simulation, and plant size (P<0.05). Small blue grama plants were significantly (P<0.05) more affected than large plants, mainly after spring and summer burns. Mortality of broomgrass muhly was slightly affected by burning treatments in either evaluation year, with average mortality of 1% and 2% for 2005 and 2006. Brickellbush mortality was significantly affected by burning season (P<0.05), and plant size (P<0.05). Spring and winter burns were the most detrimental seasons for small brickellbush plants. Broomweed plants were severely affected (P<0.05) by all burn treatments, regardless of fuel load simulation and plant size, with 82% average mortality. Spring and summer burning with high fuel load simulations reduced basal area of large blue grama plants. However these changes were similar (P>0.05) to unburned plants that decreased 8%. Winter burning with high fuel load had a positive effect (P<0.05) on basal area of large blue grama plants, with an increase of 37%. Small blue grama plants had a positive response to all burning treatments regardless of fuel load simulations, with average increases of 80%, 41%, and 31% for spring, summer, and winter burns respectively. Nevertheless, these changes were similar (P>0.05) with unburned plants that showed increased basal area of 41%. Basal area of muhly plants was generally reduced by all burn treatments. Basal area of large muhly plants had average reductions of 24% and 48% with summer and winter burns, while spring, summer, and winter burns reduced average basal area of small muhly plants by 2%, 4%, and 47% respectively.Item Correlation of weather and other variables to mesquite damage by fire(Texas Tech University, 1970-05) Britton, Carlton M.Not availableItem Effect of defoliation patterns and developmental morphology on forage productivity and carbohydrate reserves in WW-B.Dahl Grass [Bothriochloa bladhii (Retz) S.T. Blake](Texas Tech University, 2008-08) Villanueva-Avalos, Jose F.; Villalobos, Carlos; Britton, Carlton M.; Wester, David B.; Sosebee, Ronald; Patino, Reynaldo; Rideout-Hanzak, SandraThis study was conducted to develop strategies to improve WW-B Dahl establishment, and increase forage productivity using different management practices. Specific objectives included: 1) to quantify plant morphology in WW-B.Dahl plants at three growth stages; 2) to determine forage yield, quality, and leaf and stem seasonal pattern regrowth in WW-B.Dahl plants under different patterns of defoliation; 3) to evaluate total non-structural carbohydrate (TNC) concentrations and TNC pool sizes under different defoliation intensities; and 4) to evaluate seed and storage times to increase germination of WW-B.Dahl grass. Three hundred sixty WW-B.Dahl phytomers in 19-l pots were used. Pots were irrigated twice each week (1.17 liters wk-1), and maintained under greenhouse conditions at 30.2°C during 153 days in 2006. Experimental treatments were composed for three factors: 1) growth stages (GS): vegetative (V), reproductive (R), and post-reproductive (PR); 2) intensity of defoliation (ID): 0, 45, 65, and 85%; and 3) day after defoliation (DAD): 0, 3, 6, and 9 days. Variables evaluated included developmental morphology through the mean stage count (MSC) index and its variability (SMSC), forage yield (FY) and quality (CP, IVDMD), residual herbage and quality (CP and IVDMD), and TNC reserves (concentration and pool sizes). Seed germination was evaluated using the ragdoll technique. Sixty treatments were composed by the interaction of age of seed or seed lot, kind of seed [dehulled and hulled], and storage time at 5°C (0, 2, 4, 6, 8, and 10 wk). Analysis of variance including tests for normality and homogeneous variances were performed for defoliation data, TNC reserves, and germination data. Fisher’s LSD tests at P<0.05 level were conducted to test significant differences among treatments means. Tiller variability (SMSC) throughout the growing season and vegetative tillers in late summer should be considered to plan proper grazing management in productive WW-B.Dahl stands. The high regrowth rates in vegetative stage and carbohydrate reserves replenishment (3- to 6-DAD) showed by WW-B.Dahl throughout the growing season highlighted the importance of residual herbage for plant recovery following defoliation. Forage yield, quality, regrowth rates, and carbohydrate reserves replenishment suggested that WW-B.Dahl grass may be properly used (45 to 65%) in V and R stages when a large proportion of vegetative tillers are present. According to the forage quality and carbohydrate reserves results, excellent cattle gains may be obtained in WW-B.Dahl pastures during the growing season, as well quickly plant recovery following defoliation, tiller recruitment, and rapid growth initiation the next growing season. Germination data indicated that stored dehulled seed for 2- to 8-wk at 5°C before seeding may produce better pastures of WW-B.Dahl.Item Effect of levels of irrigation on forage standing crop and quality of WW-B.Dahl (Bothriochloa bladhii) pasture under summer grazing(2006-05) Ortega-Ochoa, Carlos; Villalobos, Carlos; Wester, David B.; Britton, Carlton M.; Ethridge, Don E.; Willis, David B.Incorporation of Old World bluestem grasses into the forage/beef production system on the Texas High Plains promises acceptable results, but information on grass responses to different moisture conditions and grazing is lacking. This study investigated the effect of three levels of irrigation on forage standing crop, forage quality, and steer performance on WW-B.Dahl [Bothriochloa bladhii (Retz) S.T. Blake]. Forage utilization and economic analysis on the beef production capabilities of this grass were also evaluated. The study was conducted in Lubbock County, Texas during consecutive summers, 2003 and 2004, in a 54 hectare of WW-B.Dahl pasture. Three irrigation levels were established: no irrigation (NI), low irrigation (LI) applying 25.4 mm of water every 20 days, and high irrigation (HI) applying 25.4 mm of water every 10 days. Three grazing periods of 28 days also were arranged. Steers with initial average weight of 198 kg were used for the grazing trial. Steers were fed with a whole cottonseed supplement (S), (0.454 kg/head/day fed three times a week) and no supplement (NS). Forage standing crop in both years was affected by irrigation. Higher forage standing was observed for LI during the first year with 1,650 kg ha-1. For the second year HI produced the higher amount of forage with 2,211 kg ha-1. Irrigation affected crude protein (CP) content during 2004 and the highest CP value (7.3%) was detected in LI. In vitro dry matter digestibility, neutral digestible fiber, average daily gain, and average gain per hectare were not affected by irrigation in either year. Supplementation had an effect in ADG in 2004. Forage utilization was no affected in 2003 and 2004 neither by irrigation nor by supplementation. The economic analysis showed that beef production was more profitable in dryland-no supplement scenario in 2003 and dryland-supplement scenario in 2004. Profit in dollar/ha in 2003 and 2004 under these scenarios was $306 and $223 respectively. Overall results for this study suggest that WW-B.Dahl has potential to improve beef production under dryland conditions in the Texas High Plains.Item The differences between white-tailed and mule deer fawning habitat, and the effectiveness of thermal imagery for capturing deer fawns(2006-12) Butler, David Alexander; Ballard, Warren B.; Britton, Carlton M.; Wallace, Mark C.There are 2 species in the genus Odocoileus found in North America. White-tailed deer (O. virginianus) are distributed across much of North America, while mule deer (O. hemionus) are restricted to the western third. The two species do occur sympatrically in 12 states including Texas. Previous research in Crockett County, Texas revealed that adults of each species partition habitat based on percent shrub cover, slope, elevation, and vegetation type and that adults of both species have high survival rates. We focused on differences between mule deer and white-tailed deer fawn parturition dates, parturition sites, bed sites, and how bed site characteristics may affect survival. In order to increase our fawn sample we attempted to use thermal infrared imagery to detect and capture fawns. We discuss the limitations of thermal imagery on our study area. We used univariate tests (i.e., Mann-Whitney U test and chi square goodness of fit test) to identify whether differences in birth site characteristics and parturition timing between mule deer and white-tailed deer were measurably different. We compared 7 models from parameters chosen a priori using AICC parameters estimates, SEs, and p-values to differentiate between fawn bed sites used by mule deer and white-tailed deer. We found a 33 day difference in median parturition date with white-tailed deer birthing before mule deer. Birth sites differed between species with white-tailed deer birthing at lower elevations on less steep slopes. White-tails also birthed in vegetation types associated with more mesquite and less juniper, while mule deer used more juniper vegetation types. Our best model based on AICC values (wi = 0.7061) contained 5 parameters: elevation, height of horizontal hiding cover, vegetation type, canopy plant species, and an interaction between canopy plant species and vegetation type to describe the differences between mule deer and white-tailed deer fawn bed sites. Additionally, we found that white-tailed deer fawns bedded farther from shrubs and on steeper slopes had better survival. There were no differences in bed site characteristics for mule deer fawns that survived or died. We used thermal infrared imagery with little success in an attempt to capture greater number of fawns. After 59.5 person hours of mobile searching, we observed only one fawn, and captured none. We logged 24 hours of stationary observation and observed no fawns. The lack of a forest canopy may allow vegetation, mineral, and rock to heat excessively during the afternoon causing numerous "nonfawn hot spots" making detection of neonates difficult. Furthermore, the herbaceous vegetation on our site may have prevented the unit from detecting fawns. We recommend biologists assess on site characteristics and alternative uses for thermal imagery before purchasing this expensive equipment.Item The effects of fire on Kuenzler's hedgehog cactus(Texas Tech University, 2006-08) May, Benjamin C.; Britton, Carlton M.; Wester, David B.; Thorvilson, Harlan G.Echinocereus kuenzleri is a threatened and endangered species in the mountains of south-central New Mexico. E. kuenzleri grows in the pinyon-juniper grasslands between 1,500 and 2,000 m in elevation. Little is known about E. kuenzleri. Currently, land management practices to control woody species distribution, especially juniper, avoid E. kuenzleri habitat to reduce possible negative effects on the species. One of the more common management practices in this area is prescribed fire. To study the effects of prescribed fire on E. kuenzleri, 109 cacti were burned and 109 cacti were monitored as control plants. Macro- and micro-habitat characteristics were described in detail to help understand the effects of fire on E. kuenzleri. Burning was conducted in 2004 and 2005. Cacti were monitored for 1 to 2 years after treatment. Prescribed fire had no effect on the mortality of E. kuenzleri in the conditions of this study. Furthermore, prescribed fire had no effects on the frequency of flowering of cacti or on the number of flowers and fruits per cacti. These results suggest that prescribed fire would not have a detrimental effect on the population of E. kuenzleri 1 to 2 years after burning under the conditions of this study.