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  • 1
    Electronic Resource
    Electronic Resource
    Soil-surface carbon dioxide efflux and microbial biomass in relation to tree density 13 years after a stand replacing fire in a lodgepole pine ecosystem (2003)
    Oxford, UK : Blackwell Science Ltd
    Global change biology 9 (2003), S. 0 
    Details
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: The effects of fire on soil-surface carbon dioxide (CO2) efflux, FS, and microbial biomass carbon, Cmic, were studied in a wildland setting by examining 13-year-old postfire stands of lodgepole pine differing in tree density (〈 500 to 〉 500 000 trees ha−1) in Yellowstone National Park (YNP). In addition, young stands were compared to mature lodgepole pine stands (∼110-year-old) in order to estimate ecosystem recovery 13 years after a stand replacing fire. Growing season FS increased with tree density in young stands (1.0 µmol CO2 m−2 s−1 in low-density stands, 1.8 µmol CO2 m−2 s−1 in moderate-density stands and 2.1 µmol CO2 m−2 s−1 in high-density stands) and with stand age (2.7 µmol CO2 m−2 s−1 in mature stands). Microbial biomass carbon in young stands did not differ with tree density and ranged from 0.2 to 0.5 mg C g−1 dry soil over the growing season; Cmic was significantly greater in mature stands (0.5–0.8 mg C g−1 dry soil). Soil-surface CO2 efflux in young stands was correlated with biotic variables (above-ground, below-ground and microbial biomass), but not with abiotic variables (litter and mineral soil C and N content, bulk density and soil texture). Microbial biomass carbon was correlated with below-ground plant biomass and not with soil carbon and nitrogen, indicating that plant activity controls not only root respiration, but Cmic pools and overall FS rates as well. These findings support recent studies that have demonstrated the prevailing importance of plants in controlling rates of FS and suggest that decomposition of older, recalcitrant soil C pools in this ecosystem is relatively unimportant 13 years after a stand replacing fire. Our results also indicate that realistic predictions and modeling of terrestrial C cycling must account for the variability in tree density and stand age that exists across the landscape as a result of natural disturbances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2486.2003.00626.x
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  • 2
    Electronic Resource
    Electronic Resource
    Landscape Patterns and Legacies Resulting from Large, Infrequent Forest Disturbances (1998)
    Springer
    Ecosystems 1 (1998), S. 497-510 
    Details
    ISSN: 1435-0629
    Keywords: Key words: disturbance; forest ecosystem; landscape; legacy; fire; hurricane; tornado; volcano; flood; Mount St. Helens; Yellowstone fires; Mississippi River.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: ABSTRACT We review and compare well-studied examples of five large, infrequent disturbances (LIDs)—fire, hurricanes, tornadoes, volcanic eruptions, and floods—in terms of the physical processes involved, the damage patterns they create in forested landscapes, and the potential impacts of those patterns on subsequent forest development. Our examples include the 1988 Yellowstone fires, the 1938 New England hurricane, the 1985 Tionesta tornado, the 1980 eruption of Mount St. Helens, and the 1993 Mississippi floods. The resulting landscape patterns are strongly controlled by interactions between the specific disturbance, the abiotic environment (especially topography), and the composition and structure of the vegetation at the time of the disturbance. The very different natures of these interactions yield distinctive temporal and spatial patterns and demand that ecologists increase their knowledge of the physical characteristics of disturbance processes. Floods and fires can occur over a long period, whereas volcanic eruptions and wind-driven events often last for no more than a few hours or days. Tornadoes and floods produce linear patterns with sharp edges, but fires, volcanic eruptions, and hurricanes can affect broader areas, often with gradual transitions of disturbance intensity. In all cases, the evidence suggests that LIDs produce enduring legacies of physical and biological structure that influence ecosystem processes for decades or centuries.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100219900046
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  • 3
    Electronic Resource
    Electronic Resource
    Coarse Woody Debris following Fire and Logging in Wyoming Lodgepole Pine Forests (2000)
    Springer
    Ecosystems 3 (2000), S. 472-483 
    Details
    ISSN: 1435-0629
    Keywords: Key words: coarse woody debris; lodgepole pine; Pinus contorta; timber harvesting; fire; Yellowstone National Park; Wyoming; clear-cutting.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The accumulation and decomposition of coarse woody debris (CWD) are processes that affect habitat, soil structure and organic matter inputs, and energy and nutrient flows in forest ecosystems. Natural disturbances such as fires typically produce large quantities of CWD as trees fall and break, whereas human disturbances such as timber harvesting remove much of the CWD. Our objective was to compare the amount of CWD removed and left behind after clear-cutting to the amount consumed and left behind after natural fires in Rocky Mountain lodgepole pine. The masses of fallen logs, dead-standing trees, stumps, and root crowns more than 7.5 cm in diameter were estimated in clear-cut and intact lodgepole pine forests in Wyoming and compared to estimates made in burned and unburned stands in Yellowstone National Park (YNP), where no timber harvesting has occurred. Estimates of downed CWD consumed or converted to charcoal during an intense crown fire were also made in YNP. No significant differences in biomass of downed CWD more than 7.5 cm in diameter were detected between burned stands and those following a single clear-cut. However, the total mass of downed CWD plus the mass of snags that will become CWD was nearly twice as high in burned stands than in clear-cuts. In YNP, approximately 8% of the downed CWD was consumed by fire and an additional 8% was converted to charcoal, for an estimated loss of about 16%. In contrast, approximately four times more wood (70%) was removed by clear-cutting. Considering all CWD more than 7.5 cm in diameter that was either still present in the stand or removed by harvesting, slash treatment, or burning, clear-cut stands lost an average of 80 Mg ha−1 whereas stands that burned gained an average of 95 Mg ha−1. Some CWD remains as slash and stumps left behind after harvesting, but stands subjected to repeated harvesting will have forest floor and surface soil characteristics that are beyond the historic range of variability of naturally developing stands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100210000041
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  • 4
    Electronic Resource
    Electronic Resource
    The nitrogen cycle in lodgepole pine forests, southeastern Wyoming (1985)
    Springer
    Biogeochemistry 1 (1985), S. 257-275 
    Details
    ISSN: 1573-515X
    Keywords: Ecosystem ; fixation ; forest floor ; immobilization ; loadings ; mineralization ; throughfall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Storage and flux of nitrogen were studied in several contrasting lodgepole pine (Pinus contorta spp.latifolia) forests in southeastern Wyoming. The mineral soil contained most of the N in these ecosystems (range of 315–860 g · m−2), with aboveground detritus (37.5–48.8g · m−2) and living biomass (19.5–24.0 g · m−2) storing much smaller amounts. About 60–70% of the total N in vegetation was aboveground, and N concentrations in plant tissues were unusually low (foliage = 0.7% N), as were N input via wet precipitation (0.25 g · m−2 · yr−1), and biological fixation of atmospheric N (〈0.03 g · m−2 · yr−1, except locally in some stands at low elevations where symbiotic fixation by the leguminous herbLupinus argenteus probably exceeded 0.1 g · m−2 · yr−1). Because of low concentrations in litterfall and limited opportunity for leaching, N accumulated in decaying leaves for 6–7 yr following leaf fall. This process represented an annual flux of about 0.5g · m−2 to the 01 horizon. Only 20% of this flux was provided by throughfall, with the remaining 0.4g · m−2 · yr−1 apparently added from layers below. Low mineralization and small amounts of N uptake from the 02 are likely because of minimal rooting in the forest floor (as defined herein) and negligible mineral N (〈 0.05 mg · L−1) in 02 leachate. A critical transport process was solubilization of organic N, mostly ‘fulvic acids’. Most of the organic N from the forest floor was retained within the major tree rooting zone (0–40 cm), and mineralization of soil organic N provided NH4 for tree uptake. Nitrate was at trace levels in soil solutions, and a long lag in nitrification was always observed under disturbed conditions. Total root nitrogen uptake was calculated to be 1.25 gN · m−2 · yr−1 with estimated root turnover of 0.37-gN · m−2 · yr−1, and the soil horizons appeared to be nearly in balance with respect to N. The high demand for mineralized N and the precipitation of fulvic acid in the mineral soil resulted in minimal deep leaching in most stands (〈 0.02 g · m−2 · yr−1). These forests provide an extreme example of nitrogen behavior in dry, infertile forests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02187202
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