Treesearch

Widespread tree mortality from mountain pine beetle (MPB; Dendroctonus ponderosae Hopkins) outbreaks has prompted forest management activities to reduce crown fire hazard in the Rocky Mountain region. However, little is known about how beetle-related salvage logging and biomass utilization options affect woody surface fuel loads and fuel moisture dynamics. We compared these attributes in salvage-logged lodgepole pine (Pinus contorta var. latifolia Engelm. Ex S. Wats.) stands harvested using either biomass removal (whole-tree harvest) or biomass retention (bole only harvest) prescriptions...

Fire is both a natural and anthropogenic disturbance influencing the distribution, structure, and functioning of terrestrial ecosystems around the world. Many plants and animals depend on fire for their continued existence. Others species, such as rainforest plants species, are extremely intolerant of burning and need protection from fire. The properties of a fire regime are changing as the natural world’s landscapes become fragmented and human influence becomes pervasive. A sound understanding of fire and its effects on ecosystems is an essential prerequisite for effectively managing this...

Disturbances are major drivers of ecological dynamics and it is the cumulative effects of disturbances across space and time that define a disturbance regime and dictate biodiversity by influencing the ranges of vegetation structures, compositions, and processes on landscapes. This range and variation of landscape characteristics under historical disturbance regimes can form an envelope of viable conditions that can serve as important benchmarks or references in land management. Historical range and variation (HRV) is the expression of the full range of landscape characteristics that...

Temperature profoundly affects ecology, a fact ever more evident as the ability to measure thermal environments increases and global changes alter these environments. The spatial structure of thermalscapes is especially relevant to the distribution and abundance of ectothermic organisms but the ability to describe biothermal relationships at extents and grains relevant to conservation planning has been limited by small or sparse datasets. Here, we combine a large occurrence database of >23,000 aquatic species surveys with stream microclimate scenarios supported by an equally large temperatu...

Our understanding of how climate and fire have impacted quaking aspen (Populus tremuloides Michx.) communities prior to the 20th century is fairly limited. This study analysed the period between 4500 and 2000 cal. yr BP to assess the pre-historic role of climate and fire on an aspen community during an aspen-dominated period.

Wildfire risk assessment is increasingly being adopted to support federal wildfire management decisions in the United States. Existing decision support systems, specifically the Wildland Fire Decision Support System (WFDSS), provide a rich set of probabilistic and risk‐based information to support the management of active wildfire incidents. WFDSS offers a wide range of decision‐support components, including fire behavior modeling, fire weather information, air quality and smoke management, economics, organization assessment, and risk assessment. Here we focus on WFDSS’s provision of...

Seeds of the winter annual Bromus tectorum lose primary dormancy in summer and are poised to germinate rapidly in the autumn. If rainfall is inadequate, seeds remain ungerminated and may enter secondary dormancy under winter conditions. We quantified conditions under which seeds enter secondary dormancy in the laboratory and field and also examined whether contrasting B. tectorum genotypes responded differently to dormancy induction cues. The study also extends previous hydrothermal time models for primary dormancy loss and germination timing in B. tectorum by using similar models to...

Dendroclimatic research has long assumed a linear relationship between tree-ring increment and climate variables. However, ring width frequently underestimates extremely wet years, a phenomenon we refer to as ‘wet bias’. In this paper, we present statistical evidence for wet bias that is obscured by the assumption of linearity. To improve tree-ring-climate modeling, we take into account wet bias by introducing two modified linear regression models: a linear spline regression (LSR) and a likelihood-based wet bias adjusted linear regression (WBALR), in comparison with a quadratic regression...

Understanding the degree of spatial fidelity exhibited by individuals within a species increases our ability to manage for desired future outcomes. Elk (Cervus elaphus) is a closely managed species in the Western US, but there is little research evaluating their summer home-range fidelity. Elk summer-fall homeranges overlap considerably with aspen (Populus tremuloides)-dominated forest types, and elk can impact aspen regeneration because it is a preferred browse species. We evaluated the fidelity of 72 adult female elk to individual summer-fall home ranges in northwestern Colorado, USA,...

The recent mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreaks had unprecedented effects on lodgepole pine (Pinus contorta var. latifolia) in western North America. We used data from 165 forest inventory plots to analyze stand conditions that regulate lodgepole pine mortality across a wide range of stand structure and species composition at the Fraser Experimental Forest in Colorado, USA. Forest inventory data were then combined with Landsat 7 Enhanced Thematic Mapper Plus (ETM +) imagery and boosted regression trees modeling to map outbreak severity (proportion of basal area...