124 citations from the AGRICOLA Database
1992 - March 2002
Water Quality Information Center
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Descriptors: forest-fires; history; lakes; sediment; core-sampling; charcoal; magnetism; air-temperature; rain; vegetation; fire-ecology; climatic-change; oregon
Abstract: High-resolution analysis of macroscopic charcoal in sediment cores from Little Lake was used to reconstruct the fire history of the last 9000 years. Variations in sediment magnetism were examined to detect changes in allochthonous sedimentation associated with past fire occurrence. Fire intervals from ca. 9000 to 6850 calendar years BP averaged 110 +/- 20 years, when the climate was warmer and drier than today and xerophytic vegetation dominated. From ca. 6850 to 2750 calendar years BP the mean fire interval lengthened to 160 +/- 20 years in conjunction with the onset of cool humid conditions. Fire-sensitive species, such as Thuja plicata Donn ex D. Don. Tsuga heterophylla (Raf.) Sarg., and Picea sitchensis (Bong.) Carr., increased in abundance. At ca. 4000 calendar years BP, increases in allochthonous sedimentation increased the delivery of secondary charcoal to the site. From ca. 2750 calendar years BP to present, the mean fire interval increased to 230 +/- 30 years as cool humid conditions and mesophytic taxa prevailed. The Little Lake record suggests that fire frequency has varied continuously on millennial time scales as a result of climate change and the present-day fire regime has been present for no more than 1000 years.
Descriptors: fire-retardants; chemical-composition; toxicity; exposure; daphnia-magna; algae; water-hardness; ammonia; nitrate-nitrogen; nitrites; concentration; adverse-effects; trophic-levels; laboratory-tests; comparisons
Descriptors: fire-retardants; formulations; toxicity; pimephales-promelas; developmental-stages; ova; mortality; adverse-effects; ammonia; nitrates; nitrites; water-quality; nontarget-organisms; nontarget-effects; forest-fires; hard-water; soft-water
Descriptors: fire-retardants; formulations; toxicity; rainbow-trout; developmental-stages; adverse-effects; mortality; susceptibility; water-quality; water; abnormal-behavior; ammonia; nitrate-nitrogen; nitrites; concentration; toxicology; testing; aquatic-environment; hard-water; soft-water
Abstract: Laboratory studies were conducted with five early life stages of rainbow trout, Oncorhynchus mykiss, to determine the acute toxicities of five fire-fighting chemical formulations in standardized soft and hard water. Eyed egg, embryo larvae, swim-up fry, and 60- and 90-d posthatch juveniles were exposed to three fire retardants (Fire-Trol LCG-R, Fire-Trol GTS-R, and Phos-Chek D75-F) and two fire-suppressant foams (Phos-Chek WD-881 and Silv-Ex). Swim-up fry were generally the most sensitive life stage, whereas the eyed-egg was the least sensitive. Toxicity of fire-fighting formulations was greater in hard water than in soft water for all life stages tested with Fire-Trol CTS-R and Silv-Ex and for 90-d-old juveniles tested with Fire-Trol LCG-R. The fire-suppressant foams were more toxic than the fire retardants. The 96-h median lethal concentrations (LC50s) were ranked from the most toxic to the least toxic formulation as follows (ranges are the lowest and highest 96-h LC50 calculated for each formulation): Phos-Chek WD-881 (11-44 mg/L). Silv-Ex (11-78 mg/L), Phos-Chek D75-F (218->3,600 mg/L), Fire-Trol GTS-R (207->6,000 mg/L), and Fire-Trol LCG-R (872->10,000 mg/L). Toxicity values suggest that accidental entry of fire-fighting chemicals into aquatic environments could adversely affect fish populations.
Descriptors: riparian-vegetation; botanical-composition; plant-communities; environmental-factors; site-factors; variation; altitude; streams; fire-effects; california; valley-width
Descriptors: fire-control; helicopters; buckets; environmental-impact; wildlife-conservation; endangered-species; idaho; fire-management
Descriptors: forests; forest-fires; wildfires; forest-ecology; environmental-impact; ecosystems; simulation-models; precipitation; evaluation; risk-assessment; cycling; soil-depth; soil-fertility; sloping-land; hydrophobicity; soil-chemistry; erosion; species-differences; natural-regeneration; colorado
Descriptors: limnology; paleoecology; logging; forest-fires; water-quality; lakes; watersheds; chrysophyta; botanical-composition; temporal-variation; species-diversity; hydrology; ontario
Abstract: The frequency and intensity of large-scale watershed disturbances (e.g., clearcuts and wildfires) is increasing in northwestern Ontario. Timber harvesting and wildfires have been shown to alter water quantity and quality in stream ecosystems. Unfortunately, scientific studies of these impacts on lakes are considerably rarer. Using paleolimnological techniques, we examined the remains of scaled chrysophytes in sediment cores from four lakes that have had the majority of their watersheds clearcut, two lakes that have had large forest fires in their watersheds, and two lakes that have had minimal watershed disturbance. Lakes in this study showed minor changes in the composition of scaled chrysophytes at a temporal resolution of 2 - 4 years, despite removal of over 90% of the forest. Furthermore, temporal variability in the species assemblages were similar in all lakes. A gradual change in the species assemblages of all lakes suggested a regional influence may have been responsible. We hypothesize that hydrological changes brought about by a regional drought from 1970 to 1990 may have exerted an overriding influence on lakes over this time period.
Descriptors: sewage-sludge; erosion; runoff; water-quality; forest-fires
Abstract: Soil erosion and nutrient losses are great concerns following forest wildfires. Biosolids application might enhance revegetation efforts while reducing soil erodibility. Consequently, we applied Denver Metro Wastewater District composted biosolids at rates of 0, 40, and 80 Mg ha-1 to a severely burned, previously forested site near Buffalo Creek, CO to increase plant cover and growth. Soils were classified as Ustorthents, Ustochrepts, and Haploborols. Simulated rainfall was applied for 30 min at a rate of 100 mm h-1 to 3- x 10-m paired plots. Biosolids application rates did not significantly affect mean total runoff (p < 0.05). Sediment concentrations were significantly greater (p < 0.05) from the control plots compared with the plots that had received the 80 Mg biosolids ha-1 rate. Biosolids application rate had mixed effects on water-quality constituents; however, concentrations of all runoff constituents for all treatment rates were below levels recommended for drinking water standards, except Pb. Biosolids application to this site increased plant cover, which should provide erosion control.
Descriptors: forest-fires; fire-effects; rehabilitation; watersheds; forest-damage
Descriptors: forest-ecology; forest-fires; history; holocene-soils; lakes; paleobotany; paleoclimatology; paleoecology; palynology; plant-succession; sediment; vegetation-types; climate; florida
Descriptors: streams; wildfires; environmental-impact; benthos; sediment; aquatic-insects; aquatic-invertebrates; california
Descriptors: soil-organic-matter; nitrogen; phosphorus; exchangeable-cations; losses-from-soil; water-erosion; fire-effects; spain
Descriptors: soil-types-genetic; vegetation-types; prescribed-burning; autumn; spring; runoff; water-erosion; sediment; losses-from-soil; fire-effects; seasonal-variation; arizona
Abstract: Prescribed burning of vegetation may increase the potential for surface runoff and erosion. Changes in surface runoff and sediment production were evaluated with time following fall and spring burns at two different soil and vegetation type locations in southeastern Arizona. Rainfall simulations were conducted immediately after prescribed burns on four replicate areas and 1 yr later following a repeat burn on the same areas, and compared with paired unburned areas. The burn treatment and evaluation sequence was repeated in a second year on new areas to evaluate differences in years. After the first burn, runoff and sediment production on unburned and burned areas were similar within locations, and were greater at one location than the other. One location showed significantly more runoff and sediment production in the fall season on both unburned and burned areas after the first burn treatment. There was significantly greater runoff and sediment production from the burned areas after the second burn and the burned areas were now similar between locations. Runoff and sediment production for the fall season and for the second year on the 1-yr-old areas was higher at both locations, regardless of treatment. The increases in runoff and sediment production were greater from the burning than the season or year effects after 1 yr. The management implications for these locations and conditions are that, immediately after a rangeland burn, runoff and sediment production maybe unchanged, but within 1 yr significant increases can occur and significant seasonal and yearly differences may occur irrespective of a burn.
Descriptors: watersheds; forests; wildfires; catchment-hydrology; runoff; evapotranspiration; floods; frequency; france
Abstract: This paper presents the results of a study of the hydrological consequences of a wildfire in a small Mediterranean basin during the first 12 months after the event. The Rimbaud basin is a nested sub-basin of the Real Collobrier research and experimental network, which has been continuously monitored since 1967. In August 1990, 85% of its surface area was burnt providing an interesting case study to analyse the hydrological consequences of fire. Models have been calibrated using a 23 year period before the fire and they have been used to simulate what the response would have been if the wildfire had not taken place. Differences between observed and simulated data are analysed, giving special importance to the changes in the annual runoff yield and in the flood regimes. There is a 30% increase in the annual runoff yield related to the reduction in evapotranspiration due to the destruction of the vegetation cover. On the other hand, there are pronounced changes in the shape of the flood hydrographs, and the flood frequency is greatly increased. The 10-year return period flow estimated before the fire was exceeded three times in the year although the rainfall events did not exceed the 1-year return period 12 h rainfall. The quantity and quality of the data collected during the pre-fire period and the possibility of comparing the hydrological responses of similar basins differently affected by fire, give a special relevance to this case study.
Descriptors: riparian-vegetation; forest-management; ecosystems; streams; forest-ecology; forest-fires; plant-communities; microhabitats; senescence; understory; shrubs; botanical-composition; competitive-ability; plant-competition; age-of-trees; oregon
Descriptors: forest-fires; clearcutting
Descriptors: shrubs; vegetation; population-dynamics; plant-communities; climatic-factors; climatic-change; disturbed-land; erosion; fires; precipitation; rain; seasonal-variation; wildfires; water-erosion; fire-effects; erosivity; botanical-composition; ecosystems; ulex; ulex-parviflorus
Descriptors: fire; fire-effects; fire-ecology; runoff; sediment; rain; simulation; regrowth; vegetation; temperature; botanical-composition; species-differences; ground-cover; revegetation; soil-organic-matter; water-erosion; heathlands
Descriptors: forest-ecology; ecosystems; natural-resources; land-use; forest-management; wildfires; stand-density; biomass; crown; wildlife; habitats; sustainability; forestry; fire-effects; watersheds
Descriptors: erosion-control; wildfires; vegetation; sowing; fire-prevention; plant-communities; atriplex-confertifolia; artemisia-tridentata; vegetated-waterways; nevada; greenstripping
Descriptors: grasslands; shrubs; ecosystems; deserts; geographical-distribution; rangelands; livestock; overgrazing; plant-succession; sustainability; erosion; pollution; water-quality; surface-water; water-resources; geology; climate; soil; hydrology; plant-communities; vegetation; wildlife; land-management; fires; fire-ecology; literature-reviews; new-mexico
Descriptors: chaparral-soils; entisols; burnt-soils; cercocarpus-betuloides; quercus-turbinella; site-factors; prescribed-burning; fire-effects; soil-fertility; nitrogen; phosphorus; nutrient-availability; nitrate-nitrogen; ammonium-nitrogen; litter-plant; arizona; burnt-versus-unburnt-soils
Descriptors: forest-fires; wildfires; erosion; erosion-control; chaparral; establishment
Descriptors: ponds; charcoal; sediment; relationships; forest-fires; fire-ecology; forest-ecology; quercus; forest-trees; deciduous-forests; history; paleoecology; new-york; fire-history
Descriptors: fire-suppression; rural-areas; water-supply; estimated-costs; homeowners'-insurance; plastic-pipes
Descriptors: peatlands; forest-fires; ecosystems; fire-ecology; forest-ecology; fire-effects; growing-media; forest-litter; roots; stand-characteristics; stand-development; boreal-forests; age; dendrochronology; soil-chemistry; horizons; soil-depth; humus; humification; carbon-nitrogen-ratio; bitumen; soil-ph; soil-water; porosity; soil-fertility
Descriptors: arundo-donax; ecology; weed-control; habitats; riparian-vegetation; riparian-forests; plant-succession; wildfires; water-quality; rivers; plant-competition; wildlife; species-diversity; competitive-ability; asexual-reproduction; integrated-pest-management; glyphosate; literature-reviews; california
Descriptors: pinus-ponderosa; ecosystems; forest-ecology; forest-fires; grazing; erosion; fire-control; fuel-appraisals; forest-management; cycling; growth; biodiversity; plant-diseases; forest-decline; decomposition; literature-reviews; western-states-of-usa
Descriptors: pastoralism; farming; fire; prescribed-burning; erosion; plant-communities; savannas; humid-zones; agricultural-regions; environmental-impact; ethiopia
Descriptors: catchment-hydrology; nitrogen; phosphorus; iron; manganese; prescribed-burning; losses-from-soil; northern-territory
Descriptors: forest-fires; wildfires; erosion; chaparral; grasses; sowing; sloping-land; california
Descriptors: repellency; soil-water; soil-physical-properties; fire-effects; fynbos; catchment-hydrology; sediment-yield; overland-flow; south-africa
Descriptors: watersheds; heathland; prescribed-burning; water-quality; stream-flow; overland-flow; ions; seasonal-variation; ph; water-yield; losses-from-soil; catchment-hydrology; spain
Abstract: Dry heathlands at La Calma (Montseny, NE Spain) are periodically burnt by shepherds to improve the pasture. The effects of such fires on water quality and on the output fluxes of dissolved and particulate material were studied by comparing an unburnt 6.3 ha catchment with a 10.1 ha catchment burnt in 1983 for which some pre-burn data exist. Additional data from another 22.5 ha catchment burnt in 1982, without preburn information, were used. Burning increased mean annual streamflow by at least 36% during the first 2 years after fire. Overland flow on burnt slopes had higher NO3- and K+ concentrations than that on unburnt slopes. Fire had little impact on streamwater chemistry; only slight but statistically significant increases in NO3- concentrations and in pH and decreases in K+ and SO4(2-) were found. As a result of the increased water yield, dissolved nutrient losses via streamflow increased by at least 36% in the first 2 years after burning. Despite this increase, nutrient budgets calculated at one burnt catchment showed that, except for Na2+ and Mg2+, it received more dissolved nutrients from bulk deposition than it lost through streamflow. Bed load transport, the dominant process of particulate matter export, remained low during the first 4 years after burning. Both burnt and unburnt catchments received much more particulate matter from bulk deposition than they lost through bed load transport. It is concluded that the studied prescribed burn of these dry heathlands had little effect on catchment. outputs of dissolved and particulate material. Lack of change of streamwater chemistry after a complete burn of the heathland testifies to the efficiency of the retention by the soil of nutrients leached from the ash, and nutrient uptake by regrowing vegetation.
Descriptors: water-pollution; streams; groundwater; air-pollutants; nitrate-nitrogen; ammonium; nitrogen-oxides; deposition; stream-flow; wildfires; fire-effects; nitrification; prescribed-burning; chaparral; vegetation-management; california; fire-regimes; mitigation
Descriptors: boreal-forests; acid-rain; air-temperature; climatic-change; drought; fire-effects; streams; sulfates; water-pollution; watersheds; wildfires; ontario
Descriptors: land-use; fires; fire-effects; erodibility; erosion; mediterranean-climate; wildfires; old-fields; abandoned-land; soil-chemistry; soil-physical-properties; agricultural-land; fuel-appraisals; plant-succession; chronosequences; soil-temperature; prediction; estimation; forest-soils; spain
Descriptors: forest-soils; ammonium-sulfate; forest-litter; carbon; nitrogen; carbon-nitrogen-ratio; forest-fires; wildfires; logging-effects; whole-tree-logging; watersheds; soil-organic-matter; natural-regeneration; deciduous-forests; coniferous-forests; maine
Abstract: Northern forest soils represent large reservoirs of C and N that may be altered by ecosystem perturbations. Soils at three paired watershed in Maine were investigated as case studies of experimentally elevated N deposition, wildfire, and whole-tree harvesting. Eight years of experimental (NH4)2SO4 additions at the Bear Brook Watershed in Maine significantly reduced forest-floor C/N ratios from 30.6 to 23.4. Forest-floor C and N pools were lower in the treated watershed (38 Mg C ha(-1), 1612 kg N ha(-1)) compared with the reference (75 Mg C ha(-1), 2372 kg N ha(-1)). Fifty years after wildfire at Acadia National Park, the burned watershed with hardwood regeneration had significantly lower forest-floor C and N concentrations (208 g C kg(-1) soil, 9.9 g N kg(-1) soil) than the reference watershed dominated by a softwoods (437 g C kg(-1) soil, 12.8 g N kg(-1) soil). Forest-floor C and N pools were lower in the burned watershed (27 Mg C ha(-1), 1323 kg N ha(-1)) compared with the reference (71 Mg C ha(-1), 2088 kg N ha(-1)). At the Weymouth Point, the harvested watershed regenerated to spruce-fir, the dominant stand type that existed before the harvest, and it had significantly lower forest-floor C concentrations and pools (406 g C kg(-1) soil, 24 Mg C ha(-1)) than the reference (442 g C kg(-1) soil, 39 Mg C ha(-1)) after 17 yr. All perturbations studied were associated with lower forest-floor C pools.
Descriptors: wildfires; forest-fires; fire-effects; grasses; sowing; erosion; chaparral; lolium-multiflorum; sloping-land; ground-cover; california
Descriptors: ecosystems; rivers; watersheds; history; climate; flooding; drought; water-stress; fires; infectious-diseases; resource-utilization; natural-resources; information-needs; literature-reviews; communities; adaptation; evolution; sustainability; mathematical-models; simulation; new-mexico
Descriptors: wildfires; fire-effects; hazards; assessment; prevention; natural-disasters; erosion; mud-flows; flooding; geological-sedimentation; erosion-control; soil-stabilization; vegetation-management; california
Descriptors: forests; lakes; logging; forest-fires; communities; forest-management; disturbed-land; watersheds; water-quality; biomass; population-density; geographical-variation; phosphorus; chlorophyll; nitrogen; carbon-dioxide; nutrient-availability; quebec; alberta
Descriptors: forest-soils; wildfires; burnt-soils; reclamation; poultry-manure; cattle-slurry; sewage-sludge; application-to-land; lolium-perenne; revegetation-plants; biomass-production; nitrogen; nutrient-uptake; nitrogen-content; plant-composition; nutrient-content; phosphorus; potassium; calcium; magnesium; nutrient-availability; soil-toxicity; phytotoxicity; soil-fertility
Abstract: The efficacy of three abundant organic wastes: poultry manure (PM), cattle slurry (CS) and sewage sludge (SS) for the reclamation of burnt soils was evaluated. A forest soil, previously furnace-heated in order to simulate exposure to a high-intensity wildfire, was labelled with nitrogen-15 (15N) to evaluate the contribution of N derived from the organic waste to the burnt soil and vegetation. Four treatments were performed with the heated 15N-labelled soil: an unamended control soil (S) and three waste amended soils (S+PM, S+CS and S+SS) at a dose waste of 167 mg total N kg-1 soil. Lolium perenne was grown in all the pots for 3 months. In each treatment the phytomass produced and its N content decreased significantly in the following order of treatments: S+PM much greater than S+CS > S+SS much greater than S. The percentage of plant N derived from the waste was similar in the S+PM (22.8%) and S+CS (24.0%) treatments, but significantly lower in the S+SS treatment (16.5%). At the end of the 3 month experimental period, the available N reserves (phytomass N + soil inorganic N) in the control soil accounted for 51.5-71.5% of those in the S+PM, S+CS and S+SS treatments, whereas the yield of the plants was only 13.4-29.8% of that in the manured soils. These results demonstrated the importance of the addition of organic wastes, particularly PM, for the recovery of the vegetation cover and for the stabilization of the soil ash layer. They also showed that the level of N was not the main controlling factor of plant growth in the control soil, which, moreover, did not show evidence of a shortage of macronutrients, i.e. phosphorus, potassium, calcium or magnesium. It is. hypothesized that, as occurs in heat-sterilized soils, phytomass production in the control-heated soil could have been inhibited by the heat-induced production of phytotoxic compounds, their negative effects being microbially or chemically suppressed by the addition of organic wastes.
Descriptors: adenostoma-fasciculatum; ceanothus-greggi; seedling-growth; water-potential; soil-water; fire-effects; chaparral; california
Descriptors: wildfires; forest-fires; watersheds; watershed-management; fire-effects; mapping; erosion; usda; burn-intensity; usda-forest-service; burned-area-emergency-rehabilitation
Descriptors: fynbos; cycling; soil-flora; biological-activity-in-soil; watersheds; fire-effects; deposition; south-africa
Descriptors: fire-effects; water-yield; evaporation; transpiration; plant-communities; fynbos; broadleaved-deciduous-forests; woodlands; garrigue; literature-reviews
Descriptors: forest-fires; wildfires; fire-effects; aquatic-communities; aquatic-organisms; fishes; hydrology; sediment; arizona; new-mexico
Descriptors: forests; forest-fires; sustainability; biomass; soil-chemistry; soil-flora; microbial-flora; soil-physical-properties; forest-ecology; ecosystems; vegetation; nutrient-availability; soil-fertility; botanical-composition; volatilization; ash; cycling; mineralization; erosion; leaching; denitrification; soil-organic-matter; literature-reviews
Descriptors: water-repellent-soils; forest-soils; catchment-hydrology; montana; idaho
Abstract: Infiltration rates in undisturbed forest environments are generally high. These high infiltration rates may be reduced when forest management activities such as timber harvesting and/or prescribed fires are used. Post-harvest residue burning is a common site preparation treatment used in the Northern Rocky Mountains, USA, to reduce forest fuels and to prepare sites for natural and artificial tree regeneration. Prescribed burn operations attempt to leave sites with the surface condition of a low-severity burn. However, some of the areas often experience surface conditions associated with a high-severity burn which may result in hydrophobic or water repellent conditions. In this study, infiltration rates were measured after logging slash was broadcast burned from two prescribed burns. The two sites were in Northern Rocky coniferous forests of Douglas-fir/lodgepole pine and ponderosa pine/Douglas-fir. Simulated rainfall was applied to one-square meter plots in three, 30-min applications at 94 mm h-1 within the three surface conditions found after the burn: unburned-undisturbed areas, low-severity burn areas and high-severity burn areas. Runoff hydrographs from the rainfall simulations were relatively constant from the plots that were in unburned-undisturbed areas and in areas subjected to a low-severity burn. These constant runoff rates indicate constant hydraulic conductivity values for these surface conditions even though there was variation between plots. Hydrographs from the rainfall simulation plots located within areas of high-severity burn indicate greater runoff rates than the plots in low-severity burn areas especially during the initial stages of the first rainfall event. These runoff rates. decreased to a constant rate for the last 10 min of the event. These results indicate hydrophobic or water repellent soil conditions, which temporarily cause a 10-40% reduction in hydraulic conductivity values when compared to a normal infiltrating soil condition. Since variability was high for these forest conditions, cumulative distribution algorithms of hydraulic conductivity provide a means to account for the inherent variability associated with these hillslopes and different surface conditions cause by fire.
Descriptors: grasslands; fire-effects; range-management; canopy; botanical-composition; upland-areas; upland-soils; erosion; fire-resistance; prosopis; quercus; arizona
Descriptors: wetlands; chamaecyparis-thyoides; plant-ecology; plant-succession; paleoecology; pollen-analysis; community-ecology; plant-communities; age-structure; stand-structure; fire-ecology; fire-effects; logging-effects; massachusetts
Abstract: Fire history and vegetation change over the past millennium and modern successional trends in a Chamaecyparis thyoides (Atlantic white cedar) wetland on Cape Cod, Massachusetts were investigated using fine-resolution pollen analysis and stand age-structure analyses. Before European settlement (c. 1650 AD) low cedar pollen percentages correspond with abundant charcoal, whereas cedar dominates when charcoal values are low. Five fires occurred at 100-200-year intervals in prehistoric time. Since settlement, fires have been rare and cedar dominates the pollen profile. During the past two centuries timber cutting has become a significant factor in the vegetation dynamics of this system. In the nineteenth century intensive cutting resulted in the establishment of cedar. During the first half of the twentieth century, light timber thinnings favoured Acer rubrum (red maple) regeneration. In the past few decades, neither cedar nor its principal associate, red maple, have regenerated beneath the undisturbed cedar overstorey. Our results indicate that, at this site, vegetation composition and successional trends have largely been controlled by allogenic factors in both pre- and post-settlement times. Vegetation changes resulting from autogenic factors are not evident during the 1000-year study period. Age-structure analyses of modern stands in combination with fine-resolution pollen analyses are useful in comparing current vegetation dynamics with those of earlier times. In the 600-800 years before establishment of the current mature stand, cedar did not persist for more than 100-200 years without stand-regenerating fires. Thus the survival of the current stand much beyond its present age of c. 150 years would be atypical compared to the centuries prior to settlement. The present lack, of cedar. centuries prior to settlement. The present lack, of cedar regeneration suggests that a management policy excluding disturbance would eventually lead to a decline in the importance of cedar. Our results suggest that an understanding of processes that influence community composition and structure over long periods of time may indicate conservation objectives and management guidelines different from those directed at the preservation of communities that, at a given point in time, appear to be unique on the landscape.
Descriptors: riparian-vegetation; burning; tamarix; salix; fires; recovery; water-potential; water-stress; transpiration; california; tamarix-ramosissima; salix-gooddingii
Descriptors: vegetation; watersheds; fire-effects; fire-ecology; alkalinity; lakes; water; ph; paleoecology; bacillariophyta; pollen-analysis; sediment; dendrochronology; water-quality; sulfur; iron; manganese; acidity; freshwater-ecology; elements; finland; recent-paleoecology
Abstract: The effects of catchment fire on lake Pieni Majaslampi are examined by means of geochemical, charcoal, pollen, and diatom analyses of surface sediments. Particular emphasis is paid to pH responses in this naturally acid, weakly buffered, small catchment lake. An increase of c. 0.9 units in diatom-inferred pH correlates with dendro-chronological evidence of catchment fire around 1890. This pH rise may have beer caused by increased turbulent mixing of the water column, as well as increased inputs of clastic erosional material and atmospheric ash, rich in base cations, after the fire. Inferred pH remained high until the 1930s, after which there is a slow recovery of the system at a rate approximately 0.2 pH units per decade. The inferred pH stabilizes to a level slightly higher than the prefire value by the 1960s. High concentrations of S and Fe and elevated Fe/Mn ratios in the upper sediment layer reflect increased in-situ alkalinity generation following fire. The processes controlling the acidity dynamics in small-catchment lakes may be more complex than has hitherto been thought.
Descriptors: prescribed-burning; water-resources; fire-effects; pinus-ponderosa; hydrology; southwestern-states-of-usa; mexico
Descriptors: forest-fires; wildfires; floods; history; deforestation; new-mexico
Descriptors: boreal-forests; lakes; acidity; water-quality; sediment; pollen-analysis; bacillariophyta; alkalinity; color; charcoal; paleoecology; forest-fires; watersheds; deciduous-forests; coniferous-forests; acidification; humus; fishery-management; sweden
Abstract: 1 A Holocene sediment profile from a northern Swedish boreal forest lake was analysed for diatoms, pollen and charcoal. The diatom data were used for inferences of lake-water pH, alkalinity and colour, while the pollen and charcoal records enabled assessment of catchment vegetation changes and fire. This palaeoecological study demonstrated long-term changes in lake-water acidity as a result of catchment vegetation changes and fire. 2 The pollen record showed the transition from a deciduous-dominated forest (Betula and Alnus) 9000-8000 years BP (calibrated years) to the present coniferous-dominated forest (mainly Pinus) in the catchment of Makkassjon. Local peaks in the steadily decreasing Betula pollen curve corresponded with increases in the charcoal concentration. Picea pollen did not appear until the uppermost half of the sediment section (c. 2500 BP), and never exceeded 10% relative abundance. 3 The Holocene development in lake-water chemistry, inferred from diatom analysis, was divided into three periods: a natural acidification, a natural alkalization and a fertilization/liming period. During the long-term natural acidification period, the diatom-inferred pH and alkalinity decreased by c. 1.3 pH units and c. 80 micro eq l-1, respectively, while diatom-inferred colour increased from 10 to 40 mg Pt l-1 in the same period. These changes occurred simultaneously with a change from deciduous to coniferous forest. Using redundancy analysis (RDA) with the tree pollen as predictor variables, the Alnus, Betula or Pinus pollen record captured 41-85% of the variance in lake-water pH and alkalinity. 4 During the period of natural alkalization fire became a dominant. disturbance factor in the catchment. The charcoal record was a significant predictor of the variance in diatom-inferred pH and alkalinity during the period with frequent fires, as determined by RDA analysis with a time-restricted Monte Carlo permutation test. The inferred changes in pH and colour suggested that the reduction of soil humus played a major role in the alkalization of the acid-sensitive lake. 5 The results highlight questions about the important mechanisms for predicting the long-term effects of fire on surface-water-chemistry, which will be of crucial importance if changes in fire regime take place as a consequence of global warming.
Descriptors: fire-ecology; colorado
Descriptors: phosphorus; burnt-soils; eroded-soils; prescribed-burning; fire-effects; wildfires; soil-fertility; spatial-distribution; losses-from-soil; runoff; spain; burning-intensity
Abstract: Wildland fires can increase erosion and nutrient loss in runoff by loss of vegetative cover and changes in soil structure and chemical composition. Thus, we investigated the effect of vegetation burning intensity on the loss of particulate P forms in eroded sediments by using a sequential fractionation method that distinguishes organic and inorganic P forms of different lability. Moderate burns, while not affecting P form distribution in the soil, led to high levels of inorganic P (largely Bic-Pi, NaOH-Pi, and HCl-P) in eroded sediments, with phosphorus enrichment ratios ranging from 3.36 to 5.04. Severe burns modified P form distribution in the soil, and led to the almost complete disappearance of extractable organic P from the soil. Phosphorus form distribution in sediments eroded from the severely burnt plot was similar to that in the surface layer of the soil of that plot (0-2.5 cm). Within 10 mo of burning, and independently of burn intensity, sediments eroded from both the moderately and severely burnt plots had the same P form content and distribution as sediments eroded from control plots. As a consequence of burning, the annual total P losses due to removal of particulate matter in runoff increased from 1.42 kg ha-l (control plot) to 4.35 kg ha-1 (moderately burnt plot) and 9.10 kg ha-1 (severely burnt plot). The results of the P fractionation reveal that burning leads to a 2- to 11-fold increase in rapid-turnover inorganic and organic P contents in eroded sediments. This implies greatly increased risks of eutrophication of receiving waters.
Descriptors: forest-fires; wildfires; sloping-land; erosion; watersheds; ash; sediment; runoff-water; geomorphology; new-mexico
Descriptors: forests; wetlands; history; logging; wildfires; farms; drainage; sustainability; vegetation; soil-organic-matter; afforestation; literature-reviews; north-carolina
Descriptors: natural-grasslands; rangelands; prescribed-burning; grassland-management; fire-effects; runoff; erosion; ground-cover; ground-vegetation; seasonal-variation; loam-soils; sandy-loam-soils; spatial-variation; arizona
Abstract: Fire on rangelands used as a management tool or as an unwanted wildfire removes vegetation cover. Vegetation cover is thought to be a dominate factor controlling surface runoff and erosion. Vegetation removal by a burn should have an immediate effect on runoff and erosion. Surface runoff and sediment production were evaluated immediately after fall and spring season burns at 2 locations with different soil and vegetation types for 2 years in southeastern Arizona. The evaluations were conducted with a rainfall simulator at 2 precipitation intensities. Immediately after a burn there was not a significant change in runoff and erosion, therefore, vegetation cover by itself was concluded not to be a dominate factor controlling surface runoff and erosion. The increase found in surface runoff and sediment production from the burn plots was not significantly greater than the natural variability for the locations or seasons. Significantly higher surface runoff and sediment production was measured in the fall season compared to the spring at 1 location.
Descriptors: wildfires; eucalyptus-fastigata; fire-effects; catchment-hydrology; erosion; stream-flow; south-africa
Descriptors: mountain-forests; fynbos; afforestation; pinus-radiata; eucalyptus-fastigata; watersheds; catchment-hydrology; fire; stream-flow; flow; water-repellent-soils; overland-flow; losses-from-soil; soil-heating; soil-properties; sediment-yield; south-africa; storm-flow
Abstract: Streamflow and its storm-flow elements in four catchments were analyzed by the paired catchment method for a response to fire. Prior to burning two of the catchments were vegetated with over-mature fynbos (the indigenous scrub vegetation of the southwestern Cape, South Africa), one was afforested with Pinus radiata and the fourth with Eucalyptus fastigata. One of the fynbos catchments was burned in a prescribed fire in the late dry season. The other catchments burned in wildfires. Neither of the fynbos catchments showed a change in storm-flow. Annual total flow increases of around 16% were in agreement with model predictions, being related to the reductions in transpiration and interception. The manner of streamflow generation appeared to have remained unaltered despite the presence of some water repellency in the soils and consequent overland flow on some steep midslope sites. The two timber plantation catchments experienced large and significant increases in storm-flows and soil losses, while total flow increased by 12% in the pine catchment and decreased marginally in the eucalypt catchment. The pattern of the storm-flow increases was similar in both cases. After fire, storm hydrographs were higher and steeper though their duration was little changed. The respective first year increases in the pine and eucalypt catchments were 290% and 1110% for peak discharge, 201% and 92% for quick-flow volume, and 242% and 319% for storm response ratio. These fire effects are considered to be due to changes in storm-flow generation consistent with an increased delivery of overland flow (surface runoff) to the stream channel. This was caused, in part, by reduced infiltration resulting from water repellency in the soils of the burned catchments. Overall the hydrological effects. of fire are related to numerous interactive factors, including the degree of soil heating, the vegetation type and soil properties.
Descriptors: xeric-soils; mediterranean-climate; altitude; gradients; mountain-soils; soil-degradation; water-erosion; infiltration; runoff; sediment-yield; microaggregates; land-use; overgrazing; grazing-intensity; wildfires; goats; comparisons; climatic-change; greece
Descriptors: United-States-Soil-Conservation-Service; Watershed-management-California; Forest-fires-Environmental-aspects-California
Abstract: Shows how the Soil Conservation Service helps evaluate and then heal natural disaster damaged watersheds in southern California.
Descriptors: forest-fires; geographical-information-systems; risk-assessment; wildfires; watersheds; forests; prediction; fire-effects; simulation-models; vegetation; weather; decision-making; colorado
Descriptors: Swamp-ecology-Florida; Plant-succession-Florida; Fire-ecology-Florida
Descriptors: ecosystems; landscape; landscape-ecology; environmental-management; habitats; vegetation; land-use; species; species-diversity; disturbed-land; land-management; surveys; botanical-composition; forests; rangelands; fires; erosion; fuel-appraisals; pacific-northwest-states-of-usa
Descriptors: lakes; water-quality; organic-compounds; boreal-forests; landscape; logging-effects; watersheds; clearcutting; forest-fires; wildfires; deforestation; clearance; relationships; ultraviolet-radiation; transmittance; losses-from-soil; quebec; ontario; dissolved-organic-carbon; water-transparency
Descriptors: vegetation; paleobotany; paleoecology; palynology; pollen; environmental-impact; man; colonization; islands; biogeography; water-erosion; fires; plant-ecology; fire-ecology; land-use; archaeology; deforestation; forest-trees; botanical-composition; cook-islands; mangaia-island; human-impact
Abstract: A 7000-year-long sequence of environmental change during the Holocene has been reconstructed for a central Pacific island (Mangaia, Cook Islands). The research design used geomorphological and palynological methods to reconstruct vegetation history, fire regime, and erosion and depositional rates, whereas archaeological methods were used to determine prehistoric Polynesian land use and resource exploitation. Certain mid-Holocene environmental changes are putatively linked with natural phenomena such as eustatic sea-level rise and periodic El Nino-Southern Oscillation events. However, the most significant changes were initiated between 2500 and 1800 years and were directly or indirectly associated with colonization by seafaring Polynesian peoples. These human-induced effects included major forest clearance, increased erosion of volcanic hillsides and alluvial deposition in valley bottoms, significant increases in charcoal influx, extinctions of endemic terrestrial species, and the introduction of exotic species.
Descriptors: mixed-forests; fire-ecology; fire-effects; lakes; pollen; sediment; wood; history; burning; pollen-analysis; archaeology; paleoecology; forest-ecology; deciduous-forests; minnesota; ontario; new-york; maine; wisconsin; pennsylvania; burned-wood; fire-history
Abstract: Presettlement fire regimes in north-eastern North America and their dependence on climate, fuels, and cultural patterns are poorly understood due to lack of relevant historic or palaeoecological data. Annual records of sediment charcoal accumulation were compiled from seven sites spanning the last 2000 years and representing important climate, vegetation, and cultural settings. Results were compared across sites and across changes in Indian cultures to determine whether fire patterns might be explained by one or more of these variables. Clearly interpretable fires were restricted to the western (most xeric) portion of our study region in Pine Hardwoods of Minnesota, a single fire in Northern Hardwoods of northern Wisconsin, and cultural burning near an Iroquois village in southern Ontario. Other sites in Northern Hardwoods and Hardwood-Hemlock forests did not show clear evidence of fire. Spectral analysis suggested instances in which local fire regimes departed from regional ones. Our interpretation suggests substantially longer intervals between fires than reported in previous sediment charcoal studies. We did not find evidence for fire in mixed oak forests, where it has been speculated that fire might be necessary for oak recruitment, suggesting need for further analysis. A single site in northern Wisconsin was the only Algonquin site showing a clear increase in charcoal suggesting local fire. Algonquin use of fire for hunting may not have affected our sites. A single site in Sioux territory experienced such frequent fire that cultural effects were not evident, even when Sioux were replaced by Chippewa (Algonquin) in the 18th century. One of two Iroquois sites showed clear increases in charcoal during. occupation. The second site may not have had settlements nearby.
Descriptors: forests; forest-fires; forest-ecology; fire-ecology; palynology; charcoal; lakes; sediment; woodlands; botanical-composition; species-diversity; biodiversity; vegetation; paleoecology; switzerland
Abstract: 1) Pollen and charcoal analysis at two lakes in southern Switzerland revealed that fire has had a prominent role in changing the woodland composition of this area for more than 7000 years. 2) The sediment of Lago di Origlio for the period between 5100 and 3100 BC cal. was sampled continuously with a time interval of about 10 years. Peaks of charcoal particles were significantly correlated with repeated declines in pollen of Abies, Hedera, Tilia, Ulmus, Fraxinus excelsior t., Fagus and Vitis and with increases in Alnus glutinosa t., shrubs (e.g. Corylus, Salix and Sambucus nigra t.) and several herbaceous species. The final disappearance of the lowland Abies alba stands at around 3150 BC cal. may be an example of a fire-caused local extinction of a fire-intolerant species. 3) Forest fires tended to diminish pollen diversity. The charcoal peaks were preceded by pollen types indicating human activity. Charcoal minima occurred during periods of cold humid climate, when fire susceptibility would be reduced. 4) An increase of forest fires at about 2100 BC cal. severely reduced the remaining fire-sensitive plants: the mixed-oak forest was replaced by a fire-tolerant alder-oak forest. The very strong increase of charcoal influx, and the marked presence of anthropogenic indicators, point to principally anthropogenic causes. 5) We suggest that without anthropogenic disturbances Abies alba would still form lowland forests together with various deciduous broadleaved tree taxa.
Descriptors: forest-fires; wildfires; sediment; nutrients; ecosystems; lakes; eutrophication; land-use; prescribed-burning; smoke; algae; models; california
Descriptors: forest-fires; watersheds; streams; stream-flow; logs; dead-wood; riparian-forests; wyoming
Abstract: Following fire, changes in streamflow and bank stability in burned watersheds can mobilize coarse woody debris. In 1990 and 1991, I measured characteristics of coarse woody debris and standing riparian trees and snags in Jones Creek, a watershed burned in 1988, and in Crow Creek, an unburned watershed. The mean diameter of riparian trees along Jones Creek was less than that of trees along Crow Creek, but the coarse woody debris in Jones Creek was greater in mean diameter. Tagged debris in Jones Creek was three times as likely to move, and moved over four times as far as such debris in Crow Creek. In Jones Creek, the probability of movement was higher for tagged pieces that were in contact with the stream surface. Larger pieces tended to be more stable in both streams. It appears that increased flows and decreased bank stability following fire increased the transport of coarse woody debris in the burned watershed. Overall, debris transport in Rocky Mountain streams may be of greater significance than previously recognized.
Descriptors: geology; forest-fires; site-factors; hydrology; water-availability; soil; silt-loam-soils; sandy-loam-soils; alluvial-soils; soil-properties; vegetation; canopy; understory; mountain-forests; environmental-temperature; diurnal-variation; seasonal-variation; rain; mountain-areas; fauna; new-mexico
Descriptors: coastal-plant-communities; botanical-composition; habitats; plant-ecology; community-ecology; seed-banks; fire-ecology; wildfires; species-diversity; survival; recruitment; establishment; heathland; spatial-variation; water-table; soil-water-regimes; new-south-wales; species-richness
Descriptors: forest-fires; wildfires; forest-damage; fire-effects; riparian-vegetation; rehabilitation; resource-management; ecosystems; california
Descriptors: wildfires; national-parks; rivers; sediment; meltwater; stream-flow; runoff; precipitation; air-temperature; seasonal-variation; estimation; measurement; equations; wyoming; yellowstone-river; lamar-river
Abstract: Wildfires in 1988 burned over 2000 square miles of the greater Yellowstone area in Montana and Wyoming in the largest fires in the history of Yellowstone National Park (YNP). A four-year postfire study to estimate fire-related changes in suspended sediment transport on the Yellowstone River and its principal tributary in YNP; the Lamar River, benefitted from a recently completed three-year prefire baseline study. Both studies took daily depth-integrated samples from April through September. Fire-related changes in suspended sediment were distinguished from natural climatic variations by two methods: comparison of forecast postfire sediment loads estimated with prefire sediment-rating equations to measured postfire loads; and by postfire changes in suspended sediment load expressed per unit volume runoff. Both methods indicated postfire sediment increases that varied according to season. The higher elevation Lamar River basin had little postfire increase in spring snowmelt season sediment but large increases in summer sediment load. The Yellowstone River had postfire increases in sediment load for the spring but did not reflect the large summer increases of its upstream tributary. The reasons for the difference in postfire snowmelt sediment response are unclear but may relate to basin elevation differences, the effects of unburned watersheds, and cooler postfire springs. The few high streamflow snowmelt events in the postfire period mitigated postfire sediment increases.
Descriptors: forest-fires; erosion; sedimentation; fire-effects; risk-assessment; landscape; fire-control; forest-management; resource-management; prediction; simulation-models; vegetation; soil-texture; sloping-land; erodibility; soil-water-content; streams; watersheds; geographical-information-systems; colorado
Descriptors: erosion; fire-effects; forest-fires; mountain-areas; rain; wildfires; montana
Descriptors: watersheds; forest-management; fire-prevention; georgia; north-carolina; south-carolina
Descriptors: burnt-soils; forest-soils; forest-fires; soil-organic-matter; spain
Abstract: The reclamation of burned soils in Mediterranean environments is of paramount importance in order to increase the levels of soil protection and minimise erosion and soil loss. The changes produced in the content of total organic carbon (TOC), N (Kjeldahl) and available P, K, Ca and Mg by the addition of different doses of a municipal solid waste compost to a burned soil were evaluated during one year. The effect of organic amendment on the improvement in the vegetation cover after one year was also evaluated. The organic amendment, particularly at a high dose, increased the TOC and N-Kjeldahl content of the soil in a closely related way. The levels of available K in soil were also enhanced by the organic amendment. Although the effects on all three parameters tended to decrease with time, their values in the amended soils were higher than in the control soil, which clearly indicates the improvement in the chemical quality of the soil brought about by the organic amendment. The available P content did not seem to be influenced by organic treatment, while available Mg levels were higher than in the control during the first 4 months following organic amendment. The application of compost to the burned soil improved its fertility and favoured rapid vegetal recovery, thus minimising the risk of soil erosion.
Descriptors: forest-fires; wildfires; urban-areas; rehabilitation; erosion; erosion-control; california
Descriptors: semiarid-grasslands; ecotones; prescribed-burning; brush-control; botanical-composition; water-erosion; runoff; ground-cover; shrubs; nitrogen-content; soil-chemistry; losses-from-soil; weather
Abstract: Woody perennials have invaded semiarid grasslands throughout the Southwestern United States. This invasion was coupled with decreased grass cover and increased runoff and soil erosion. Fire, which was a natural force that shaped and maintained the grasslands, is a management tool that may aid in restoring and maintaining grass cover. However, fire also poses the risk of increasing erosion and further soil degradation because protection afforded by vegetation is reduced immediately after the fire. Using a randomized block study design, this study measured vegetation cover, soil potentially mineralizable N, and erosion associated with the first application of prescribed fire on 2 semiarid grasslands. The potential for adverse effects from these fires was great because the fires occurred at the beginning of a drought period. However, the effects of the burn were minor relative to the effects of the drought, which caused the greatest change. Grass cover on the burn plots was nearly equal to grass cover on the controls 1 year after the fire. After 2 growing seasons, grass cover was equal on the control and burn plots. Potentially mineralizable soil N and sediment transport were similar on the control and burned plots during the 2 years following the fire. Thus, prescribed fire for reducing the cover of woody perennials may not increase the risk of site degradation over that caused by drought and weather fluctuations.
Descriptors: forest-fires; erosion; runoff; sedimentation; alluvium; wyoming; montana
Abstract: Projections of the ecological effects of global climate change often include increased frequency and/or intensity of forest fires in regions of warmer and drier climate. In addition to disturbing biological systems, widespread intense fires may influence the evolution of the physical landscape through greatly enhanced sediment transport. Debris-flow to flood-streamflow sedimentation events following the 1988 fires in the Yellowstone National Park area (Wyoming and Montana, USA) have allowed us to examine the geomorphological response to fire in a mountain environment. Abundant analogous deposits in older alluvial fan sequences bear witness to past fire-related sedimentation events in northeastern Yellowstone, and radiocarbon dating of these events yields a detailed chronology of fire-related sedimentation for the past 3,500 years. We find that alluvial fans aggrade during periods of frequent fire-related sedimentation events, and we interpret these periods as subject to drought or high climatic variability. During wetter periods, sediment is removed from alluvial fan storage and transported down axial streams, resulting in floodplain aggradation. The dominant alluvial activity is strongly modulated by climate, with fire acting as a drought-actuated catalyst for sediment transport.
Descriptors: prescribed-burning; understory; erosion; spring; louisiana
Descriptors: woody-plants; stress; deforestation; disturbed-land; tropics; thinning; forests; stand-density; pollution; acid-rain; nitrogen; nutrient-excesses; leaching; salinity; seed-germination; growth; forest-ecology; ecosystems; carbon-dioxide-enrichment; climatic-change; species-diversity; geographical-distribution; soil-temperature; insect-pests; forest-fires; shifting-cultivation; flooding; mortality; plant-physiology; soil-compaction; hydrology; forest-decline; forest-plantations; soil-fertility; plant-diseases; planting-stock; agroforestry; remote-sensing; simulation-models; genetic-engineering; rotations; literature-reviews
Descriptors: mixed-forests; fires; occurrence; natural-regeneration; aerial-photography; california
Descriptors: lolium-multiflorum; seed-mixtures; revegetation; erosion; fires; losses-from-soil; hill-land; runoff; spain; santiago-de-compostela
Descriptors: vegetation-management; roadside-plants; weeds; concrete-roads; traffic-safety; visibility; non-crop-weed-control; chemical-control; cultural-weed-control; manual-weed-control; mowers; biological-control; structural-design; surface-drainage; water-erosion; fire-danger; snow; rust
Descriptors: water-repellent-soils; prescribed-burning
Abstract: This paper describes the heat transfer mechanisms operating as heat moves downward in the soil along steep temperature gradients during both wildfires and prescribed fires. The transfer of heat downward in the upper part of the soil is enhanced by the vaporization and movement of water and organic compounds. Available information on the changes in the chemistry of vaporized organic compounds is summarized and discussed. An operational theory describing the formation of a highly water repellent soil condition during fire is presented. The relationship between the formation of this fire-related watershed condition and subsequent surface runoff and erosion from wildland ecosystems is explored. Worldwide literature describing fire-induced water repellency is reviewed and summarized.
Descriptors: boreal-forests; forest-fires; carbon-cycle; decomposition; forest-soils; biomass-production; drainage; water-table; mosses; permafrost; emission; carbon-dioxide; simulation-models; manitoba
Descriptors: mixed-forests; pinus; hardwoods; prescribed-burning; felling; forest-soils; erosion; soil-water; soil-temperature; evapotranspiration; plant-competition; kalmia-latifolia; fire-effects; north-carolina
Abstract: Three southern Appalachian stands with sparse and unproductive pine-hardwood overstories and dense Kalmia latifolia L. understories were treated to restore productivity and diversity on steep slopes. An adaptation of the fell and burn practice was applied in summer and fall 1990. About one-half of the woody fuels were consumed at each site. A range of fire intensities was observed. Flame temperatures approached 800 degree C, but the heat pulse into the forest floor only reached 60 degrees C at 5 cm. Humus and charred leaf litter remained on most of the surface after burning. Evidence of soil erosion was spotty and related to points of local soil disturbance. No soil left the sites. At the end of the first growing season, 23% of the burned surfaces were covered by growing plants and 62% by residual forest floor and woody debris. Felling and burning reduced evapotranspiration so that soil in the treated areas remained moister than under adjacent uncut stands. Opening the sites increased soil temperatures 2 to 5 degrees C at 10 cm during the first 16 months after treatment.
Descriptors: site-preparation; prescribed-burning; mixed-forests; pinus; hardwoods; soil-fertility; nitrification; mineralization; nitrates; ammonium; nitrate-nitrogen; soil-water; streams; water-quality; nutrient-availability; nitrogen; national-forests; north-carolina; nantahala-national-forest
Abstract: Three paired watersheds treated with a fell and burn prescription were studied to determine the effects on soil, soil water, and strewn water. Soil nitrification and mineralization were measured by in situ closed-core incubation. Soil water was collected with porous cup lysimeters placed at 30 and 60 cm depths, and water samples were collected from streams draining control and burned areas on one of the three sites. All data were collected for 6 months prior to and 12 months after treatment. Soil ammonium (NH4(+)) content increased significantly in all three sites after burning, but the magnitude differed greatly among sites. However, there was no change in soil nitrate NO3(-) content. In situ measurements of net mineralization showed increased rates with increasing bum severity. Net nitrification displayed no treatment response. Slight and nonsignificant increases in soil water NO3(-) concentration occurred after burning in two of the three sites. Stream water NO3(-) concentrations increased in the one stream sampled. Thus, while prescribed burning increased available soil N, there was little change in N transformation rates or movement of dissolved inorganic N off site during the first year after burning.
Descriptors: woody-plants; soil-compaction; growth; inhibition; yields; traffic; machinery; animals; fire-effects; soil-structure; bulk-density; soil-texture; hydrology; aggregates; porosity; soil-air; infiltration; runoff; erosion; water-uptake; abscisic-acid; ethylene; plants; plant-composition; plant-physiology; leaf-area; respiration; mycorrhizas; mortality; mineral-nutrition; drainage; photosynthesis; soil-strength; literature-reviews
Descriptors: regosols; semiarid-soils; burnt-soils; xeric-soils; chronosequences; wildfires; fire-effects; soil-degradation; desertification; erosion; soil-profiles; soil-chemistry; nutrient-availability; soil-organic-matter; exchangeable-cations; nitrogen-content; phosphorus; nitrate-nitrogen; ammonium-nitrogen; plant-communities; plant-succession; vegetation-types; shrubs; spain
Descriptors: forest-soils; soil-solution; cations; anions; canopy; leaching; leachates; forest-fires; prescribed-burning; forest-litter; understory; water-quality; streams; surface-water; coniferous-forests; throughfall; california
Descriptors: fire-control; fire-fighting; aircraft; water; equipment; evaluation
Abstract: Canadair's CL-415 amphibious aircraft is arguably the most advanced firefighting waterbomber on the face of the earth. With its high water capacity and advanced performance, it leads the way in rapid initial attack to contain fires.
Descriptors: wildfires; palynology; aborigines; landscape; burning; history; ecosystems; habitats; paleoecology; archaeology; fauna; extinction; geomorphology; environmental-impact; nature-conservation; biodiversity; vegetation; plant-communities; erosion; literature-reviews; fire-ecology; fire-effects; plant-colonization; australia
Descriptors: boreal-forests; simulation-models; plant-succession; plant-communities; population-dynamics; palynology; charcoal; lakes; sediment; temporal-variation; vegetation; finland
Descriptors: fire-effects; erosion-control; colorado
Descriptors: forest-management; forest-fires; risk-assessment; simulation-models; planning; topography; site-factors; uses; watersheds; volume; yields; economic-analysis; biodiversity; forest-ecology; british-columbia
Descriptors: forests; forest-fires; forest-ecology; fire-ecology; forest-decline; ecosystems; forest-soils; nitrogen; soil-fertility; carbon; soil-chemistry; streams; water-quality; forest-litter; calcium; potassium; magnesium; cation-exchange; capacity; ph; spatial-distribution; fire-effects; north-carolina
Descriptors: wildfires; watersheds; national-parks; weathering; nutrients; temporal-variation; wyoming; jones-creek-watershed; crow-creek-watershed; chemical-weathering
Abstract: In 1988, wildfire burned over 50% of the Jones Creek watershed near Yellowstone Park, Wyoming. Crow Creek, an adjacent watershed, was unburned. Water quality data collected from 1989-1993 may show the fire's effect on weathering and nutrient transport. Jones Creek had 25-75% larger concentrations of dissolved solids than Crow Creek during the sampling period. Both streams revealed molar ratios consistent with the stoichiometry of andesine and pyroxene hydrolysis in the trachyandesites that underlie the basins. During 1989, nitrate transported from the unburned Crow Creek basin peaked at 2 mmol ha-1 s-1. This was twice as much as Jones Creek, possibly indicating a source from ash fallout. By 1992 these rates diminished to 0.1 mmol ha-1 s-1 in Crow Creek and increased to 1.8 mmol ha-1 s-1 in Jones Creek, suggesting later nitrate mobilization in the burned watershed. Phosphorus transported from Jones Creek basin averaged 0.011 mmol ha-1 s-1 during summer 1989, but fell to 0.004 mg ha-1 s-1 in subsequent years.
Descriptors: pinus-ponderosa; pseudotsuga-menziesii; pinus-contorta; pinus-engelmannii; wildfires; carbon; nitrogen; coniferous-forests; forest-soils; bioassays; soil-fertility; horizons; water-erosion; nutrient-availability; indicator-species; lactuca-sativa; crop-yield; fire-effects; fire-ecology; biomass; soil-organic-matter; washington
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