Texas Wintergrass and Buffalograss Response to Seasonal Fires and Clipping

There is increased interest in the use of summer-season fires to limit woody plant encroachment into grasslands, but effects of these fires on grasses are poorly understood. We quantified effects of repeated winter fires, repeated summer fires, and clipping (to simulate grazing) on aboveground total yield, live yield, and percentage of live tissue of C₃ Texas wintergrass (Nassella leucotricha [Trin. & Rupr.] Pohl.), and C₄ buffalograss (Buchloë dactyloides [Nutt.] Engelm.) in 2 experiments. Monospecific patches of each species were exposed to 1 of 3 fire treatments (no-fire, 2 winter fires in 3 years, or 2 summer fires in 3 years) and 1 of 2 clip treatments (no clip or clip once each spring). Experiment 1 evaluated effects of fire without grazing or clipping on late-growing season (late-season) yields. Late-season total yield of both species recovered from winter and summer fires within 1 or 2 growing seasons post-fire. By 3 years post-fire, Texas wintergrass late-season total yield was 2 times greater in the summer fire treatment than the winter fire or no-fire treatments, and buffalograss late-season total yield was 3 times greater in summer and winter fire treatments than in the no-fire treatment. Experiment 2 evaluated combined effects of fire and clipping the previous spring on spring-season yields. Clipping alone or with fire (summer or winter) reduced Texas wintergrass yields on more sample dates than occurred with buffalograss. By 3 years post-fire, buffalograss spring total yield was greater in all fire and fire + clip treatments than in the clip only or untreated controls. Results suggest: 1) both species were tolerant of summer fire, 2) fire in either season with or without clipping stimulated buffalograss production, and 3) buffalograss was more tolerant than Texas wintergrass to the combined effects of clipping + fire (either season).     

Mesquite,Tobosagrass, and Common Broomweed Responses to Fire Season and Intensity

There has been increasing interest in the use of summer fires to limit woody plant encroachment on grasslands, but information regarding effects of such fires on perennial grass recovery and annual forb production is also needed. Our objective was to examine effects of fire seasonality and intensity on the woody legume honey mesquite (Prosopis glandulosa Torr.), the C₄ midgrass tobosagrass (Pleuraphis mutica Buckl.), and the annual forb common broomweed (Amphiachyris dracunculoides [DC.] Nutt.). Treatments included summer fires, high-intensity winter fires, low-intensity winter fires, and no burn in replicated plots. None of the fire treatments caused whole-plant mortality (root kill) in mesquite. Mesquite aboveground mortality (top kill) was much greater after summer and high-intensity winter fires than low-intensity winter fires. Tobosagrass total yield (live + dead) was lower following summer fires and was not enhanced by any of the fire treatments for two growing seasons postfire when compared to the no-burn condition. However, tobosagrass live yield was 40% greater in the high-intensity winter fire treatment than the no-burn condition the first summer postfire and recovered in the other fire treatments by the end of the first growing season postfire. Tobosagrass percentage of live tissue was greatest in the summer fire treatment at the end of each of the two growing seasons postfire. Common broomweed cover increased in the summer fire treatment and decreased in both winter fire treatments relative to the no-burn condition by the end of the first growing season postfire. Summer fire offered no clear advantage over high-intensity winter fire with respect to mesquite suppression. However, the increase in late-season tobosagrass percentage live tissue caused by summer fire may be advantageous for forage quality. In addition, patch burning summer fires to increase broomweed cover in selected areas may be useful for wildlife habitat.     

Long-Term Effects of Fire,Livestock Herbivory Removal,and Weather Variability in Texas Semiarid Savanna

We examined how the occurrence and structure of grasses and woody plants changed after 12 yr of a fire season manipulation and removal of livestock herbivores. Applying high intensity fires in the summer preserved the structural integrity of this semiarid live oak (Quercus virginiana Mill.) savanna while decreasing or eliminating numerous problematic plants in the understory and overstory, such as prickly pear cactus (Opuntia spp.), sacahuista (Nolina texana S. Watson), Ashe juniper (Juniperus ashei J. Buchholz), Pinchot's juniper (J. pinchotii Sudw.), and honey mesquite (Prosopis glandulosa Torr.). In the less intense repeat winter burning treatments, undesirable woody plants were generally maintained at pretreatment levels in the overstory but all woody plants except Ashe juniper increased in the understory. Alternatively, areas excluded from fire in the control treatment rapidly transitioned from a grass-tree codominated savanna environment to one that is heavily dominated by woody plants. In the grass community, the most frequently occurring grass species in the winter burn treatment differed from summer burn and control treatments, whereas the summer burn treatment was not different from the control. Of the herbaceous plants, only little bluestem (Schizachyrium scoparium [Michx.] Nash) responded to fire treatments. Little bluestem increased in the winter burn treatment, remained fairly constant in the summer burn treatment, and decreased in the control. Other grasses varied largely as a function of annual weather variability, the removal of livestock, and legacy effects resulting from pre-existing variability. These findings suggest that fire can reduce or eliminate woody plant species that threaten the stability of live oak savannas while having little long-term effect on grasses desired by rangeland managers.     

Vegetation Responses to Prescribed Burning of Grazed Shortgrass Steppe

Over the past century, fire has been widely suppressed in the western Great Plains, in part because of the potential negative effects on forage production for livestock. More recently, interest in the use of prescribed fire in shortgrass steppe has increased because of the potential applications for wildlife management, control of unpalatable plant species, and restoration of historic disturbance regimes. We studied the effects of prescribed burns conducted during late winter on herbaceous production, forage nitrogen content, and plant species composition of shortgrass steppe on the Pawnee National Grassland in northeastern Colorado. Late-winter burns conducted in moderately grazed sites under a wide range of precipitation conditions during 1997–2001 did not negatively affect herbaceous production in either the first or the second postburn growing season. Burning followed by a severe drought in 2002 reduced production by 19% in the second postburn growing season of 2003. Burns temporarily suppressed the abundance of broom snakeweed (Gutierrezia sarothrae) and prickly pear cactus (Opuntia polyacantha) and enhanced forage nitrogen content during May and June of the first postburn growing season. These findings suggest that, except following severe drought, prescribed burns conducted during late winter in grazed shortgrass steppe for objectives unrelated to livestock production can also have neutral or positive consequences for livestock.     

Factors affecting milk yield,milk fat,bacterial score,and bulk tank somatic cell count of dairy farms in the central region of Thailand

A study was conducted to determine the effects of season, farm location, and farm size on farm milk yield (FMY), average milk yield per cow (AYC), milk fat, bacterial score, and bulk tank somatic cell count (BTSCC) of dairy farms in the central region of Thailand. Farms were located in the districts of Kaeng Khoi, Muaklek, Pak Chong, and Wang Muang. Collection of data was at the farm level; individual animal records were unavailable. A total of 967,110 daily farm milk yield, 58,575 milk fat and bacterial score, and 24,109 BTSCC records from 1,034 farms were collected from July of 2003 to June of 2006. There were three seasons: rainy, summer and winter. Farms were categorized into small, medium, and large according to the number of cows milked per day. Results showed that FMY and AYC were higher (p <0.05) in winter and lower in the summer and rainy seasons. In addition, the majority of small size farms had higher (p < 0.05) AYC and milk fat values, and lower bacterial score and BTSCC values than medium and large size farms.     

Veld burning in giant's castle game reserve,natal Drakensberg

A basic aim in the management of a wildlife reserve is to maintain ecological diversity. In the Giant's Castle Game Reserve the vegetation is largely composed of fire sub‐climax grasslands. Under the natural fire‐regime, before man influenced the system much, fires probably occurred at any time of the year, but mostly in summer. At present there are acute problems in controlling wildfires which occur mostly in late winter when there is an extreme fire hazard. Most of the Natal Drakensberg is now burnt by wildfires in late winter and deliberate fires in early spring. The ecological effect of the natural and present fire regimes are discussed, and a burning plan for Giant's Castle is outlined.     

Female White-Tailed Deer Body Condition and Diet After a Large Spring Wildfire

Frequency of large rangeland wildfires may increase in the southwestern United States and northeastern Mexico as a result of exotic grass invasion and reduced emphasis on livestock production, but effects of such fires on white-tailed deer (Odocoileus virginianus) are poorly documented. A large wildfire burned &spigt; 90% of the 6 151-ha Chaparral Wildlife Management Area in southern Texas during March 2008, creating an opportunity to study short-term effects of wildfire on white-tailed deer food habits, body condition, and pregnancy. We harvested 26 female deer between 7 April and 20 June 2008 and recorded dressed body weight, body condition, number of corpora lutea, and number and size of fetuses. We used rumen contents to quantify forage classes consumed. Deer ate prickly pear (Opuntia engelmannii) pads and emergent grasses during April and shifted to forbs and browse as vegetation communities recovered. Deer consumed mesquite (Prosopis glandulosa) beans and prickly pear fruit during mid-June. Body condition measures did not vary during the collection period, suggesting deer were able to acquire sufficient nutrients to meet requirements. Fetal development rate appeared normal. Precipitation (11.4 cm) during late April and May probably allowed vegetation to recover from the wildfire. White-tailed deer are resilient opportunists and were able to maintain body condition and pregnancy after a large-scale wildfire.     

不同季节、不同出栏日龄对樱桃谷鸭蛋氨酸需要量的影响

本研究结合生产实践，采用大群生产试验方法，对标准化饲养的2847栋鸭舍，同源樱桃谷商品肉鸭2925万只，按统一饲养方式和管理程序进行生产试验。试验日粮分为前期（1～19d）、中期（20～29d）和后期（30d～出栏）3个阶段，记录各饲养阶段肉鸭的采食量、增重、死亡率。结果表明：春、夏、秋、冬肉鸭氨基酸需要量的析因模型分别为：春季：METR=0．0050BGW＋0．1818W0．75；夏李：METR：O．0055BGW＋0．1554W0．75；秋季：METR=0．0050BGW＋0．1945W0．75；冬李：METR=0．0038BGW＋0．2651W0．75。春、夏、秋、冬四个季节肉鸭的蛋氨酸维持需要分别为每千克代谢体重0．1818、0．1554、0．1945、0．265lg；肉鸭每增重lg体重需要蛋氨酸为0．005、0．0055、0．005、0．0038g。冬季肉鸭摄入的蛋氨酸用于维持需要的量高于其它季节，以夏季最少，春季与秋季肉鸭用于维持需要的蛋氨酸量相当。而肉鸭冬季用于单位增重所需的蛋氨酸最少，其他季节相近。研究同时表明，不同的出栏日龄肉鸭增重lg所需的蛋氨酸量不同，随着肉鸭出栏日龄的延长，肉鸭每增重1g所需的蛋氨酸的需要量逐渐提高。     

Effect of season of burning on grass recovery in the false thornveld of the eastern cape

Abstract

Season of burning is one of the most controversial questions concerning the use of fire in veld management. In the summer rainfall areas of South Africa the generally accepted rule of burning only after the first spring rains has proven ineffectual when using fire to control bush encroachment because the fires are too cool when burnt at this time. It was therefore decided to investigate the effect of burning on the regrowth of grass when applied during mid‐winter, spring, late spring and early summer. The results showed that burning when the grass was dormant (mid‐winter) had no deleterious effect on the recovery of grass when compared with burning after the first spring rains (spring). Conversely burning when the grass was actively growing (early summer) seriously retarded its regrowth.     

Examination of Fire-Related Succession Within the Dry Mixed-Grass Subregion of Alberta With the Use of MODIS and Landsat

Fire is an important disturbance process historically present across the northern Great Plains. Previous research from northern dry mixed-grass prairie suggests that C4 (warm season) grasses replace C3 (cool season) climax species with increasing fire, particularly in the spring. This hypothesis was tested at a landscape scale at Canadian Forces Base Suffield Alberta, by exploring the relationship between ecosystem states (C3 dominant, C3/C4 codominant, C4 dominant) inferred from a MODIS multitemporal plant functional type classification (pseudo R²: 0.598, overall accuracy: 0.74) and interyear fire history digitized from the Landsat archive (1972–2007). Probit regression showed that succession processes were different between range sites, where C4-dominant pixels were positively related to fire (P < 0.001, pseudo R² = 1) and completely replaced C3-dominant pixels on loamy range sites after 14 fires in 36 yr. In contrast, C3- and C3/C4-codominant pixels were related with fire on Blowouts range sites (P < 0.001, pseudo R² = 1), where C3/C4-codominant pixels replaced C3-dominant pixels with increasing fire. Finally, there were no statistically significant relationships between ecosystem states and fire for Sands range sites. Analysis of recovery showed that after loamy pixels experienced three to six fires in 18 yr followed by 18 yr of rest, C3-dominant pixels were reduced by over 30% compared to unburned pixels. Finally, intrayear fire timing (2001–2009) was explored with the use of Wilcoxon signed-rank tests between the spatial extent of spring and summer fires, with the use of MODIS burned-area data. Results indicate that fires are not limited to the spring season (P < 0.05), but occur across the entire growing season. Although fire timing does not appear to play a role in driving succession, this ecosystem is generally sensitive to repeated fire, with recovery of C3 climax species taking decades.     

Seasonal Timing of Fire Alters Biomass and Species Composition of Northern Mixed Prairie

Fire plays a central role in influencing ecosystem patterns and processes. However, documentation of fire seasonality and plant community response is limited in semiarid grasslands. We evaluated aboveground biomass, cover, and frequency response to summer, fall, and spring fires and no fire on silty and clayey sites in semiarid, C₃-dominated grassland. The magnitude of change in biomass between years was greater than any differences among fire treatments. Still, differences existed among seasons of fire. Summer fire reduced non-native annual forb frequency (3% vs. 10% ± 2%) and Hesperostipa comata, reduced native annual forbs the first year, increased Poa secunda and bare ground, and increased Vulpia octoflora the second year. Fall fire increased grass biomass (1224 vs. 1058 ± 56 kg ? ha^? 1), but fall fire effects were generally similar to those of summer fire. Spring fire effects tended to be intermediate between no fire and summer and fall fire with the exception that spring fire was most detrimental to H. comata the first growing season and did not increase bare ground. All seasons of fire reduced litter, forb biomass, and frequency of Bromus japonicus and Artemisia spp., and they reduced H. comata, V. octoflora, and native annual forbs the first year, but increased basal cover of C₃ perennial grasses (2.2% vs. 0.6% ± 0.4%). Fire during any season increased dominance of native species compared with no fire (6.6% vs. 2.0% ± 1.0% basal cover) and maintained productivity. Seasonal timing of fire manipulated species composition, but increased C₃ perennial grass cover and native species dominance with fire during any season indicated that using fire was more important than the season in which it occurred. In addition, fire effects on the vegetation components tended to be counter to previously observed effects of grazing, suggesting fire and grazing may be complementary.     

The effect of season and vaccination for Glässer's disease and post-weaning Colibacillosis in an outdoor pig unit endemically infected with virulent strain of Haemophilus Parasuis serotype 5 and pathogenic Escherichia coli

The objective of this field trial was to determine if vaccination against Haemophilus parasuis serovar 5 (HPS 5) and pathogenic serotypes of Escherichia coli would improve nursery pig performance in an outdoor unit in different seasons. The unit was concurrently infected with HPS 5 and with different serotypes of E. coli. All piglets were born to HPS 5 vaccinated sows. The trial was carried out in four (two summer and two winter) groups. Group 1 (E. coli and HPS vaccinated, summer season) (n = 362): Piglets were vaccinated pre-weaning with inactivated E. coli-VT2e-toxin and post-weaning against HPS 5. Group 2 (non-vaccinated, summer season) (n = 349): Piglets were not vaccinated. Group 3 (E. coli and HPS vaccinated, winter season) (n = 358): The animals were analogously treated as Group 1. Group 4 (non-vaccinated, winter season) (n = 353): Piglets were not vaccinated. The following parameters were evaluated: A: average daily nursery weight gain (ADG), B: nursery mortality, C: feed efficiency (FE). No significant weight differences were detected within the vaccinated and non-vaccinated summer or winter raised groups of weaners. Summer raised weaners were significantly (P<0.05) heavier from day 35 on than winter raised animals. ADG and FE of summer raised pigs were significantly better (weeks 1-3 P<0.05; fourth week post-weaning P<0.01) during the nursery period than that of the winter raised groups. Winter raised vaccinated weaners showed during the last week of nursing significantly (P<0.05) better daily gain and feed efficiency compared with the non-vaccinated winter raised animals. Non-significant ADG and FE differences were detectable between the summer raised vaccinated or non-vaccinated groups of pig. Winter raised non-vaccinated animals suffered significantly (P<0.05) higher nursery mortality (10.63%) compared to the winter raised vaccinated animals. Implication: In cases of concurrent infections with HPS 5 and with different serotypes of E. coli, especially during winter season, vaccination against both diseases is suggested.     

Effects of Fire Exclusion on Previously Fire-Managed Semiarid Savanna Ecosystem

Long-term (> 100 yr) fire exclusion is associated with numerous ecological consequences in grasslands and savannas, including transitions into shrub- or tree-dominated systems. Several studies have reported differences in woody vegetation after multiple fires among burned and unburned rangelands, but none have reported the impacts of fire exclusion after a period of fire management. We evaluated effects of fire exclusion on herbaceous and woody canopy cover and herbaceous biomass in semiarid savanna of southwest Texas in pastures with known burn histories. Pastures were burned in summer and winter in 1994, 2000, and 2006, followed by 11 yr of fire exclusion. Between 2006 and 2017, woody subcanopy increased (5–21%) in all treatments while overstory canopy remained unchanged. Herbaceous cover decreased (5–18%) in all treatments but remained higher in burned treatments. From 2006 to 2017, herbaceous biomass declined in all treatments by > 650 kg·ha⁻¹ and was not statistically different among treatments. These trends support other research demonstrating the importance of historical mean fire return interval in maintaining grasslands and savannas.     

Fire Return Interval and Season of Fire Alter Bud Banks

Despite the importance of vegetative reproduction in annual tiller replacement, little is known about the patterns and timing of tiller recruitment from the bud bank, especially regarding fire return intervals and seasons of fire. We examined aboveground plant density, temporal patterns of tiller production, and belowground bud bank dynamics for Bouteloua gracilis (Willd ex. Kunth) Lag. ex Griffiths), Pascopyrum smithii (Rydb.) A. Löve, and Hesperostipa comata (Trin. & Rupr.) Barkworth following summer, fall, and spring prescribed fires at 2-yr, 3-yr, and 6-yr fire return intervals, and their interactions. Fire treatments were initiated in 2006, and buds were assessed July 2011 through July 2013. Density and number of reproductive B. gracilis tillers increased in 2013 following drought during 2012, unlike H. comata, which decreased reproductive tiller production. Irrespective of fire treatments, B. gracilis produced the most buds (8 ? 10 buds ? tiller^? 1) and H. comata produced the least (2 ? 3 buds ? tiller^? 1), with P. smithii producing an intermediate amount (6 ? 8 buds ? tiller^? 1). Immediate B. gracilis and P. smithii bud mortality did not occur for all season and fire return interval treatments. However, H. comata bud mortality increased immediately following summer and fall prescribed fires. Three-yr fire return intervals increased active buds throughout the 2013 winter and growing season for B. gracilis and P. smithii relative to control plots and 2- and 6-yr fire return intervals. Fire stimulated bud activity of B. gracilis and P. smithii relative to nonburned plots. The aboveground and belowground response of H. comata indicated meristem limitations following fire treatments, illustrating greater vulnerability to fire for that species than B. gracilis and P. smithii.     

Follicular progesterone levels decrease during the period of seasonal infertility in sows

Impaired reproductive performance exhibited by the domestic sow during the late summer and early autumn months is referred to as seasonal infertility. This study was carried out to determine whether there are changes in ovarian morphology and follicular steroidogenesis associated with season, which may be associated with seasonal infertility. Ovaries were collected in pairs from sows sourced from two farms and slaughtered 4 days after weaning during winter and summer. The mean progesterone concentration in follicular fluid (FF) collected from small follicles was lower in summer (701.3 ± 115.54 nm) compared with winter (1235.55 ± 164.47 nm; p<0.001). The mean progesterone concentration in the FF of large follicles was also lower in summer (1469.2 ± 156.51 nm) compared with winter (2470.9 ± 169.13 nm; p<0.001). The number of large surface antral follicles (5-8 mm in diameter) on the ovaries recovered from Farm A sows was higher during summer (17.76 ± 0.56) than in winter (15.38 ± 0.54; p<0.05). Similarly, the number of small follicles (3-4 mm in diameter) on Farm A sow ovaries was higher in summer (8.46 ± 0.66) than in winter (4.63 ± 0.53; p<0.001). In contrast, the number of small follicles on the surface of ovaries recovered from Farm B sows was higher during winter (10.17 ± 1.50) than in summer (6.45 ± 1.00; p<0.01). The number of pre-ovulatory follicles (>8 mm in diameter) was also higher in winter (1.23 ± 1.68) when compared to summer (0.51 ± 0.3; p<0.001) on the ovaries of sows from Farm B. The results suggest that there are seasonal differences in follicular steroidogenesis and ovarian dynamics. These findings add support to the theory that altered follicular steroidogenesis and ovarian morphology may possibly be the mechanism behind reduced reproductive performance during the period of seasonal infertility in sows.     

Effect of density and season on stress and behaviour in broiler breeder hens

1. We examined the effect of density (5, 7, 9 and 11 birds/m2) and season (summerand winter; different hens each season) on stress and behaviour in two flocks of 64 broiler breeder females divided among 8 pens. 2. The hens, approximately the same age and body mass in each season, were maintained on hard-packed ground, without litter, in an open-sided chicken house and were offered the same amount of food each season. 3. Mean house max/min temperatures varied between 18 and 33 degrees C in summer and 7 and 17 degrees C in winter. Mean relative humidity in summer varied between 68% at 08:00 h and 42% at 14:00 h and in winter was 64% at 08:00 h and 47% at 14:00 h. 4. No difference was found in heterophil:lymphocyte ratios among densities and between seasons; however, basophil numbers were higher in winter than in summer indicating prolonged stress in winter. 5. Stereotyped pecking increased with an increase in density and was higher in winter than in summer. Pecking on the ground was higher in winter, but was not affected by density. 6. In summer the hens spent more time lying and eating than in winter, whereas in winter the hens spent more time walking, preening and drinking than in summer. They spent the same amount of time standing in both seasons. None of these behaviours was density dependent. 7. We conclude that season had more of an effect than density on stress and behaviour in broiler breeder hens under the conditions of our study.     

The Effect of Season and Vaccination for Glässer's Disease and Post‐weaning Colibacillosis in an Outdoor Pig Unit Endemically Infected with Virulent Strain of Haemophilus Parasuis Serotype 5 and Pathogenic Escherichia coli

The objective of this field trial was to determine if vaccination against Haemophilus parasuis serovar 5 (HPS 5) and pathogenic serotypes of Escherichia coli would improve nursery pig performance in an outdoor unit in different seasons. The unit was concurrently infected with HPS 5 and with different serotypes of E. coli. All piglets were born to HPS 5 vaccinated sows. The trial was carried out in four (two summer and two winter) groups. Group 1 (E. coli and HPS vaccinated, summer season) (n = 362): Piglets were vaccinated pre‐weaning with inactivated E. coli‐VT2e‐toxin and post‐weaning against HPS 5. Group 2 (non‐vaccinated, summer season) (n = 349): Piglets were not vaccinated. Group 3 (E. coli and HPS vaccinated, winter season) (n = 358): The animals were analogously treated as Group 1. Group 4 (non‐vaccinated, winter season) (n = 353): Piglets were not vaccinated. The following parameters were evaluated: A: average daily nursery weight gain (ADG), B: nursery mortality, C: feed efficiency (FE). No significant weight differences were detected within the vaccinated and non‐vaccinated summer or winter raised groups of weaners. Summer raised weaners were significantly (P<0.05) heavier from day 35 on than winter raised animals. ADG and FE of summer raised pigs were significantly better (weeks 1–3 P<0.05; fourth week post‐weaning P<0.01) during the nursery period than that of the winter raised groups. Winter raised vaccinated weaners showed during the last week of nursing significantly (P<0.05) better daily gain and feed efficiency compared with the non‐vaccinated winter raised animals. Non‐significant ADG and FE differences were detectable between the summer raised vaccinated or non‐vaccinated groups of pig. Winter raised non‐vaccinated animals suffered significantly (P<0.05) higher nursery mortality (10.63%) compared to the winter raised vaccinated animals. Implication: In cases of concurrent infections with HPS 5 and with different serotypes of E. coli, especially during winter season, vaccination against both diseases is suggested.     

Survival of Sprouting Shrubs Following Summer Fire: Effects of Morphological and Spatial Characteristics

Efficacy of fire in reducing shrub density is low in plant communities where most woody plants resprout from stem bases and crowns following fire. Our objective was to determine the relationship of shrub mortality and recovery from summer fire to prefire shrub structural characteristics. A randomized, complete block design with two treatments (burned and control) and three blocks was used in the experiment. Within each block and treatment combination, we randomly selected 40 individuals each of brasil (Condalia hookeri M. C. Johnst.), huisache (Acacia farnesiana [L.] Willd.), and spiny hackberry (Celtis ehrenbergiana [Klotzsch] Liebm.). We estimated height, canopy diameter, number of stems, stem diameter, and distance to the nearest shrubs before ignition of fires. Fires were ignited during July and August 2001. Survival, sprout number, height, and total plant height were estimated 47–52 wk postburn. Mortality of brasil was 26 times greater on burned sites than on control sites, but mortality of huisache and spiny hackberry was negligible. Mortality of brasil varied from 0% to 68% among blocks. Postburn height and number of sprouts increased with preburn shrub height and number of stems, indicating that longer intervals of time between fires that allow shrub growth facilitate more rapid postfire recovery. Factors other than the preburn shrub structural characteristics we measured appear to influence postfire shrub survival most strongly, although these characteristics are useful in predicting postfire sprout production and shrub height.