Long-term Effects Of Fire Research Articles

Response of Chihuahuan Desert Mountain Shrub Vegetation to Burning

The effects of fire on vegetation in the desert mountain shrub community were studied on 3 to 7-year-old burned sites near the northern limits of the Chihuahurn Desert. Coverage and frequency of redberry juniper (Juniipcruspinchotii) and frequency of whitebail acacia (Acacia texends) were lower, while frequencies of catclaw mimosa (Mimosa biunc~em) and skeleton goldeneye (Viguiera stenoloba) were higher on burned sites when_compared with unburned paired piants. Lechuguiiia (Agave lecheguil&, sotoi (DasytYrion leiophylbun), and sacahuista (Nor and Texas Tech University. It is a contribution of College of Agricultural Sciences, Publication No. T-9-235. Texas Tech University. Manuscript received March 28, 1980. huan Desert. Bunting and Wright (1977) reported theeffectsof fire on desert mountain shrub vegetation 2 years after burning in the Texas Big Bend country. Kittams (1973) noted that in burned desert mountain shrub communities, catclaw mimosa (Mimosa biuncifera). skunkbush (Rhus aromatica), silver dalea (Dalea argyraea), skeleton goldeneye (Viguiera stenoloba). mountain mahogany (Cercocarpus montanus), scrub oaks (Quercus spp.), redberry juniper (Juniperus pinchotii) and alligator juniper (J. deppeana) usually recovered through some form of vegetative sprouting. He observed that lechuguilla (Agave lecheguilla), datil (Yucca baccata), and mature soto (Dasylirion leiophyllum) were usually killed by fire. ,Bunting and Wright (1977) found that fire reduced shrub cover and total grass cover 43% and 72% respectively in a desert mountain shrub community 2 years after burning. Coverage of forbs and half shrubs increased 650%. The fire significantly reduced the density or cover of sideoats grama (Bouteloua curtipendula), blue three-awn (Aristida glauca), sotol, and lechuguilla, whereas coverage contributed by skeleton goldeneye tripled through vigorous sprouting and seedling establishment on the burned area (Bunting and Wright 1977). Information pertaining to other species common to the Chihuahuan Desert is available from studies conducted elsewhere. Mortality rates for cholla (Opuntia imbricata) and pricklypear (0. phaeacantha) two growing seasons after a prescribed burn on the Texas High Plains averaged 45% and 68%, respectively (Heirman and Wright 1973). Pricklypear mortality was 3270 the first year following a prescribed burn (Cable 1967) and 28% the second growing season after an experimental tire (Reynolds and Bohning 1956), in two separate studies conducted in the Arizona Sonoran Desert. Survival of ocotillo (Fouquieria splendens) following a 62 JOURNAL OF RANGE MANAGEMENT 35(l). January 1999 wildfire in the Sonoran Desert was 33Ycfor heavily damaged plants and 50% for plants only scorched (White 1969). Regeneration occurred primarily through basal sprouting. Algerita (Berberis trifoliolata) sprouted vigorously following a wildfire in south central New Mexico (Dwyer and Pieper 1967). The objective of this study was to document longer term effects of fire on vegetation in the mountain shrub community of the Chihuahuan Desert by examining 3 to ‘I-year-old burned areas.

Long-term effects of fire on the composition and activity of the soil microflora of a subalpine, coniferous forest

The biomass, community composition, and metabolic activity of soil microorganisms were studied in adjacent burnt and unburnt areas of spruce–fir subalpine forest razed 6 years previously by a moderately severe natural fire. Similar levels of microbial biomass were observed at comparable burnt and unburnt sites, although the ratio of fungal to bacterial biomass was higher in the unburnt soils. The decreased acidity of the surface horizons in the burn probably tended to favor the development of a bacterial flora rather than a fungal flora. Microbial biomass in the burnt sites peaked earlier in the season than in the unburnt sites in response to the warmer soil temperatures and earlier thaw in the spring in the burn area.Significant differences in the species composition of the mycoflora in the organic soil horizons were observed between the burnt and unburnt sites. Apparently, these were related to qualitative differences in the recent litter. Phoma, Cladosporium, and Botrytis, which are usually associated with early stages of decomposition of herbaceous litter, were more common in the burnt soil. The mycoflora of the mineral soil horizons varied considerably from one burn site to another, possibly reflecting the geographical variation in the intensity of the burn. In overall composition, however, the mycoflora in the mineral soil horizons of the burn was not appreciably different from that of the unburnt sites.Higher laboratory rates of respiration and cellulose decomposition were observed for soil samples from the undisturbed forest. However, the rate of decomposition of cellulose in the field was much higher in the burnt sites, probably as a result of the higher soil temperatures in the burn area. Low soil temperature was concluded to be the main factor limiting microbial activities in the study area, and the removal of the insulating plant canopy and increased heat absorption by the ash in the burn area were found to increase decomposition rates, at least at this stage in the succession following the disturbance of fire.

Long-Term Effects of Fire on Cactus in the Southern Mixed Prairie of Texas

Long-Term Effects of Fire on Cactus in the Southern Mixed Prairie of Texas

An Analysis of Forest Fire History on the Little Firehole River Watershed, Yellowstone National Park

Fire is now recognized as a major process in Rocky Mountain coniferous forests, with many ecosystem patterns and processes being affected as much by fire as by climate and soil. For this reason there is a move toward reinstating fire as a natural process within our National Parks and Wilderness Areas, a move which is proceeding cautiously, however, because there is still much that we do not know about fire's natural role in ecosystems. In Yellowstone National Park, where a fire management plan is now in effect, an important question is: What is the natural frequency and size of wildfires in different Park ecosystems? An understanding of natural fire frequency and size is important not only in formulating and evaluating fire management plans, but also in evaluating long-term effects of fire on wildlife habitat, productivity, nutrient cycling, and other ecosystem processes.

Effect of Fire on Southern Mixed Prairie Grasses

Highlight: The long-term effect of fire was studied on the major grass species of west Texas when the winter-spring precipitation was 0 to 40% above normal. This and other studies indicate that sideoats grama and Texas wintergrass are harmed by fire. Buffalograss, blue grama, and sand dropseed were neither harmed nor benefited by fire. Vine-mesquite, Arizona cottontop, little bluestem, plains bristlegrass, and Texas cupgrass increased after burning for 1 or 2 years.

Prescribed Burning in an Aspen – Mixed Hardwood Forest

The effects of prescribed burning and complete clearcutting on Populustremuloides and associated hardwoods and shrubs were compared for 8 years after commercial harvest of a 60-year-old P. tremuloides stand. Because of the lack of suitable burning weather, P. tremuloides suckers were 2 years old before the burn could be made. All suckers were killed by fire and new suckers were more numerous but less vigorous, probably because of heat damage to shallow sucker-producing roots, loss of nitrogen, and reduced root carbohydrate reserves. Although prescribed fire can effectively control residual hardwood overstories detrimental to P. tremuloides sucker growth and survival, the long term effect of fire on sucker growth is unknown. Fire can be used to prepare sites for P. tremuloides regeneration when other methods are unavailable or impractical. Burning should be done during the first dormant season following logging. Effort should be made to distribute slash uniformly to provide even burning conditions. Burning prescription guidelines are given.