Research Database
Displaying 1 - 7 of 7
Topographic Variation in Structure of Mixed-Conifer Forests Under an Active-Fire Regime
Year: 2012
Management efforts to promote forest resiliency as climate changes have often used historical forest structure and composition to provide general guidance for fuels reduction and forest restoration treatments. However, it has been difficult to identify what stand conditions might be fire and drought resilient because historical data and reconstruction studies are generally limited to accurate estimates only of large, live tree density and composition. Other stand features such as smaller tree densities, dead wood, understory structure, regeneration, and fuel loads have been difficult to…
Publication Type: Journal Article
Spatially extensive reconstructions show variable-severity fire and heterogeneous structure in historical western United States dry forests
Year: 2012
Aim Wildfire is often considered more severe now than historically in dry forests of the western United States. Tree-ring reconstructions, which suggest that historical dry forests were park-like with large, old trees maintained by low-severity fires,are from small, scattered studies. To overcome this limitation, we developed spatially comprehensive reconstructions across 927,000 ha in four landscapes, using anew method based on land surveys from c. 1880. Location Dry forests of the western United States. Methods We reconstructed forest structure for four large dry-forest landscapes using…
Publication Type: Journal Article
Multiple successional pathways and precocity in forest development: can some forests be born complex?
Year: 2012
Background. In forests subject to stand-replacing disturbances, conventional models of succession typically overlook early-seral stages as a simple re- organization/establishment period. These models treat structural development in essentially ‘relay floristic’ terms, with structural complexity (three-dimensional heterogeneity) developing primarily in old-growth stages, only after a closed-canopy ‘self-thinning’ phase and subsequent canopy gap formation. However, is it possible that early-successional forests can sometimes exhibit spatial complexity similar to that in old-growth forests – i.e…
Publication Type: Journal Article
The leaf-area shrinkage effect can bias paleoclimate and ecology research
Year: 2012
Premise of the Study: Leaf area is a key trait that links plant form, function, and environment. Measures of leaf area can be biased because leaf area is often estimated from dried or fossilized specimens that have shrunk by an unknown amount. We tested the common assumption that this shrinkage is negligible. Methods: We measured shrinkage by comparing dry and fresh leaf area in 3401 leaves of 380 temperate and tropical species and used phylogenetic and trait-based approaches to determine predictors of this shrinkage. We also tested the effects of rehydration and simulated fossilization on…
Publication Type: Journal Article
Communication of the Role of Natural Variability in Future North American Climate
Year: 2012
As climate models improve, decision-makers' expectations for accurate climate predictions are growing. Natural climate variability, however, poses inherent limits to climate predictability and the related goal of adaptation guidance in many places, as illustrated here for North America. Other locations with low natural variability show a more predictable future in which anthropogenic forcing can be more readily identified, even on small scales. We call for a more focused dialogue between scientists, policymakers and the public to improve communication and avoid raising expectations for…
Publication Type: Journal Article
Long-term perspective on wildfires in the western USA
Year: 2012
Understanding the causes and consequences of wildfires in forests of the western United States requires integrated information about fire, climate changes, and human activity on multiple temporal scales. We use sedimentary charcoal accumulation rates to construct long-term variations in fire during the past 3,000 y in the American West and compare this record to independent firehistory data from historical records and fire scars. There has been a slight decline in burning over the past 3,000 y, with the lowest levels attained during the 20th century and during the Little Ice Age (LIA, ca.…
Publication Type: Report
Characterizing Fire-on-Fire Interactions in Three Large Wilderness Areas
Year: 2012
The interaction of fires, where one fire burns into another recently burned area, is receiving increased attention from scientists and land managers wishing to describe the role of fire scars in affecting landscape pattern and future fire spread. Here, we quantify fire-on-fire interactions in terms of frequency, size, and time-since-previous fire (TSPF) in three large wilderness areas in Montana and Idaho, USA, from 1984 to present, using spatially consistent large fire perimeter data from the Monitoring Trends in Burn Severity (MTBS) dataset. The analysis is supplemented with less consistent…
Publication Type: Journal Article