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In forests, total belowground carbon (C) flux (TBCF) is a large component of the C budget and represents a critical pathway for delivery of plant C to soil. Reducing uncertainty around regional estimates of forest C cycling may be aided by incorporating knowledge of controls over soil respiration and TBCF. Photosynthesis, and presumably TBCF, declines with advancing tree size and age, and photosynthesis increases yet C partitioning to TBCF decreases in response to high soil fertility. We hypothesized that these causal relationships would result in predictable patterns of TBCF, and partitioning of C to TBCF, with natural variability in leaf area index (LAI), soil nitrogen (N), and tree height in subalpine forests...
Spruce beetle (Dendroctonus rufipennis Kirby) outbreaks are important disturbances affecting subalpine forests of Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa), and lodgepole pine (Pinus contorta) in the southern Rocky Mountains. However, little is known about the influences of these outbreaks on overall forest dynamics. We used age-structure analyses and dendrochronological techniques to investigate the effects of a major spruce beetle outbreak on stand composition, dominance, tree age and size structures, radial growth, and succession in subalpine forests in Colorado. This outbreak, which occurred in the 1940s, caused a shift in dominance from spruce to fir and a reduction in average and...
Age and size data on over 2200 trees were used to reconstruct developmental.patterns and regeneration dynamics of four successional and two climax stands of subalpine forests in the Colorado Front Range. The dominant tree species of these forests are Engelmann spruce (Picea engelmannii), subalpine fir (Abies lasiocarpa), limber pine (Pinusflexilis), and lodgepole pine (Pinus contorta). Due to relatively weak relationships between age and size for all four species, patterns of stand development could not have been reliably inferred from size data alone. Following wildfire on the most xeric sites, limber pine is the principal pioneer species and dominates seedling establishment for 50 to 100 or more years. At most...
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Landscape carbon (C) flux estimates are necessary for assessing the ability of terrestrial ecosystems to buffer further increases in anthropogenic carbon dioxide (CO2) emissions. Advances in remote sensing have allowed for coarse-scale estimates of gross primary productivity (GPP) (e.g., MODIS 17), yet efforts to assess spatial patterns in respiration lag behind those of GPP. Here, we demonstrate a method to predict growing season soil respiration at a regional scale in a forested ecosystem. We related field measurements (n=144) of growing season soil respiration across subalpine forests in the Southern Rocky Mountains ecoregion to a suite of biophysical predictors with a Random Forest model (30 m pixel size). We...
Understanding the effect of variation in climate on large-fire occurrence across broad geographic areas is central to effective fire hazard assessment. The El Nin?o? Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) affect winter temperature and precipitation regimes in western North America through mid-latitude teleconnections. This study examines relationships of ENSO and the PDO to drought-induced fire occurrence in subalpine forests of three study areas across the Rocky Mountains: Jasper National Park (JNP, northern Rockies), Yellowstone National Park (YNP, central Rockies) and Rocky Mountain National Park (RMNP, southern Rockies) over the 1700?1975 period. Large-scale climatic anomalies...
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Subalpine Connectivity of areas of high elevation and high human footprint in the North Pacific Landscape Conservation Cooperative study area. This application provides Subalpine Connectivity for 2000 and 2080 (A1B). The North Pacific Forest Landscape Connectivity Project uses three main geospatial layers as inputs into the creation of resistance map grids. One-km was decided as the resolution for the final resistance grids. The three primary geospatial layers used in this analysis were a digital elevation model (DEM), a vegetation layer, and a human footprint layer. Due to the geographic extent of the North Pacific Landscape Conservation Cooperative, digital elevation models from different sources had to...
A five-stand chronosequence spanning >500 yr is used to characterize changes in age structure, overstory mortality, recruitment, and understory growth in developing Colorado Engelmann spruce (Picea engelmannii)-subalpine fir (Abies lasiocarpa) forests. Stand development follows a postdisturbance sequence of colonization, spruce exclusion, spruce reinitiation, and second-generation forest. This model of spruce-fir forest development reflects a range of disturbance intensities from large conflagrations to small-scale tree deaths. Catastrophic disturbance initiates stand development, and canopy gap replacements occur at predictable times during stand development as the life-spans of the two species are expressed. Previous,...


    map background search result map search result map Subalpine Connectivity of areas of high elevation and high human footprint in the NPLCC, 2000 (A1B) Data release for estimating soil respiration in a subalpine landscape using point, terrain, climate and greenness data Data release for estimating soil respiration in a subalpine landscape using point, terrain, climate and greenness data Subalpine Connectivity of areas of high elevation and high human footprint in the NPLCC, 2000 (A1B)