Research Database
Displaying 1 - 6 of 6
Tree mortality from drought, insects, and their interactions in a changing climate
Year: 2015
Climate change is expected to drive increased tree mortality through drought, heat stress, and insect attacks, with manifold impacts on forest ecosystems. Yet, climate-induced tree mortality and biotic disturbance agents are largely absent from process-based ecosystem models. Using data sets from the western USA and associated studies, we present a framework for determining the relative contribution of drought stress, insect attack, and their interactions, which is critical for modeling mortality in future climates. We outline a simple approach that identifies the mechanisms associated with…
Publication Type: Journal Article
Interactions among spruce beetle disturbance, climate change and forest dynamics captured by a forest landscape model
Year: 2015
The risk of bark beetle outbreaks is widely predicted to increase because of a warming climate that accelerates temperature-driven beetle population growth and drought stress that impairs host tree defenses. However, few if any studies have explicitly evaluated climatically enhanced beetle population dynamics in relation to climate-driven changes in forest composition and structure that may alter forest suitability for beetle infestation. We synthesized current understanding of the interactions among climate, spruce beetles (Dendroctonus rufipennis) and forest dynamics to parameterize and…
Publication Type: Journal Article
Forest disturbance accelerates thermophilization of understory plant communities
Year: 2015
1. Climate change is likely to shift plant communities towards species from warmer regions, a processtermed ‘thermophilization’. In forests, canopy disturbances such as fire may hasten this processby increasing temperature and moisture stress in the understory, yet little is known about the mechanismsthat might drive such shifts, or the consequences of these processes for plant diversity.2. We sampled understory vegetation across a gradient of disturbance severity from a large-scalenatural experiment created by the factorial combination of forest thinning and wildfire in California.Using…
Publication Type: Journal Article
Native and exotic plant species respond differently to wildfire and prescribed fire as revealed by meta-analysis
Year: 2015
Questions: Wildfire is a natural disturbance that shapes vegetation characteristics worldwide, while prescribed fire is increasingly used to modify vegetation composition and structure. Due to invasion of many ecosystems by exotic species, a concern of land managers is whether wildfire and prescribed fire alter plant communities in favour of exotics. We assessed the global literature describing community-level responses of native and exotic species groups to wildfire and prescribed fire and characterized the geographic and temporal scope of the data to inform research needs. Location:…
Publication Type: Journal Article
Representing climate, disturbance, and vegetation interactions in landscape models
Year: 2015
The prospect of rapidly changing climates over the next century calls for methods to predict their effects on myriad, interactive ecosystem processes. Spatially explicit models that simulate ecosystem dynamics at fine (plant, stand) to coarse (regional, global) scales are indispensable tools for meeting this challenge under a variety of possible futures. A special class of these models, called landscape models (LMs), simulates dynamics at intermediate scales where many critical ecosystem processes interact. The complicated dependencies among climate, disturbance, and vegetation present a…
Publication Type: Journal Article
Wildland fire deficit and surplus in the western United States, 1984-2012
Year: 2015
Wildland fire is an important disturbance agent in the western US and globally. However, the natural role of fire has been disrupted in many regions due to the influence of human activities, which have the potential to either exclude or promote fire, resulting in a "fire deficit" or "fire surplus", respectively. In this study, we developed a model of expected area burned for the western US as a function of climate from 1984 to 2012. We then quantified departures from expected area burned to identify geographic regions with fire deficit or surplus. We developed our model of area burned as a…
Publication Type: Journal Article