Showing papers by "Thomas T. Veblen published in 2001"
TL;DR: In this paper, fire histories were compared between the southwestern United States and northern Patagonia, Argentina using both documentary records and tree-ring reconstructions over the past several centuries, and the interhemispheric synchrony of fire regimes in these two distant regions is tentatively interpreted to be a response to decadalscale changes in ENSO activity.
Abstract: Fire histories were compared between the southwestern United States and northern Patagonia, Argentina using both documentary records (1914 ‐ 87 and 1938‐96, respectively) and tree-ring reconstructions over the past several centuries. The two regions share similar fire‐climate relationships and similar relationships of climatic anomalies to the El Nino‐Southern Oscillation (ENSO). In both regions, El Nino events coincide with above-average cool season precipitation and increased moisture availability to plants during the growing season. Conversely, La Nina events correspond with drought conditions. Monthly patterns of ENSO indicators (southern oscillation indices and tropical Pacific sea surface temperatures) preceding years of exceptionally widespread fires are highly similar in both regions during the 20th century. Major fire years tend to follow the switching from El Nino to La Nina conditions. El Nino conditions enhance the production of fine fuels, which when desiccated by La Nina conditions create conditions for widespread wildfires. Decadal-scale patterns of fire occurrence since the mid-17th century are highly similar in both regions. A period of decreased fire occurrence in both regions from c. 1780 ‐1830 coincides with decreased amplitude and/or frequency of ENSO events. The interhemispheric synchrony of fire regimes in these two distant regions is tentatively interpreted to be a response to decadal-scale changes in ENSO activity. The ENSO‐fire relationships of the south-western USA and northern Patagonia document the importance of high-frequency climatic variation to fire hazard. Thus, in addition to long-term trends in mean climatic conditions, multi-decadal scale changes in year-to-year variability need to be considered in assessments of the potential influence of climatic change on fire regimes.
183 citations
TL;DR: This work investigated interannual and multidecadal variability in fire regimes, as related to climate and human land-use in Pike National Forest, central Colorado, finding short and long-term trends in fire-scarred areas are similar to previous studies.
Abstract: We investigated interannual and multidecadal variability in fire regimes, as related to climate and human land-use in Pike National Forest, central Colorado. Short and long-term trends in fire-scar...
104 citations
TL;DR: Analysis of differences in wind damage among tree species and stands following a severe blowdown in 1997 affecting over 10 000 ha of subalpine forest in the Routt Divide area of northern Colorado found standing dead conifers were more likely to be snapped than uprooted, and taller trees were morelikely to be damaged.
Abstract: As windstorm intensity increases above some threshold, disturbance spread and damage patterns are expected to be less strongly shaped by preblowdown forest composition and structure than by the pattern of the storm itself. We examined this generalization by analyzing differences in wind damage among tree species and stands following a severe blowdown in 1997 affecting over 10 000 ha of subalpine forest in the Routt Divide area of northern Colorado, U.S.A. Individual tree traits such as species, height, and status as standing dead or alive strongly influenced the amount and type (uprooting vs. snapping) of wind damage. Populus tremuloides Michx. exhibited much less uprooting and overall damage than the conifers. Among the canopy trees of the conifer species, Pinus contorta Dougl. ex. Loud and Abies lasiocarpa (Hook.) Nutt. sustained the lowest and highest rates of snapping, respectively. Standing dead conifers were more likely to be snapped than uprooted, and taller trees were more likely to be damaged tha...
61 citations
TL;DR: For the subalpine zone of the Colorado Front Range, little information exists on fire history documenting the evolution of fire behavior and management decisions as discussed by the authors. But, for example, the information is limited.
Abstract: Resource managers rely on knowledge of fire history to guide management decisions, but for the subalpine zone of the Colorado Front Range little information exists on fire history documenting chang
59 citations