Research Database
Displaying 21 - 35 of 35
Spatiotemporal patterns of unburned areas within fire perimeters in the northwestern United States from 1984 to 2014
Year: 2018
A warming climate, fire exclusion, and land cover changes are altering the conditions that produced historical fire regimes and facilitating increased recent wildfire activity in the northwestern United States. Understanding the impacts of changing fire regimes on forest recruitment and succession, species distributions, carbon cycling, and ecosystem services is critical, but challenging across broad spatial scales. One important and understudied aspect of fire regimes is the unburned area within fire perimeters; these areas can function as fire refugia across the landscape during and after…
Publication Type: Journal Article
Disequilibrium of fire-prone forests sets the stage for a rapid decline in conifer dominance during the 21st century
Year: 2018
The impacts of climatic changes on forests may appear gradually on time scales of years to centuries due to the long generation times of trees. Consequently, current forest extent may not reflect current climatic patterns. In contrast with these lagged responses, abrupt transitions in forests under climate change may occur in environments where alternative vegetation states are influenced by disturbances, such as fire. The Klamath forest landscape (northern California and southwest Oregon, USA) is currently dominated by high biomass, biodiverse temperate coniferous forests, but climate change…
Publication Type: Journal Article
Fire Refugia: What Are They, and Why Do They Matter for Global Change?
Year: 2018
Fire refugia are landscape elements that remain unburned or minimally affected by fire, thereby supporting postfire ecosystem function, biodiversity, and resilience to disturbances. Although fire refugia have been studied across continents, scales, and affected taxa, they have not been characterized systematically over space and time, which is crucial for understanding their role in facilitating resilience in the context of global change. We identify four dichotomies that delineate an overarching conceptual framework of fire refugia: unburned versus lower severity, species-specific versus…
Publication Type: Journal Article
Temperate forest health in an era of emerging megadisturbance
Year: 2015
Although disturbances such as fire and native insects can contribute to natural dynamics of forest health, exceptional droughts, directly and in combination with other disturbance factors, are pushing some temperate forests beyond thresholds of sustainability. Interactions from increasing temperatures, drought, native insects and pathogens, and uncharacteristically severe wildfire are resulting in forest mortality beyond the levels of 20th-century experience. Additional anthropogenic stressors, such as atmospheric pollution and invasive species, further weaken trees in some regions. Although…
Publication Type: Journal Article
Does wildfire likelihood increase following insect outbreaks in conifer forests?
Year: 2015
Although there is acute concern that insect-caused tree mortality increases the likelihood or severity of subsequent wildfire, previous studies have been mixed, with findings typically based on stand-scale simulations or individual events. This study investigates landscape- and regional-scale wildfire likelihood following outbreaks of the two most prevalent native insect pests in the US Pacific Northwest (PNW): mountain pine beetle (MPB; Dendroctonus ponderosae) and western spruce budworm (WSB; Choristoneura freemani). We leverage seamless census data across numerous insect and fire events to…
Publication Type: Journal Article
Eastern Washington Forest Health: Hazards, Accomplishments and Restoration Strategy
Year: 2014
Much of the 10 million acres of forestland in eastern Washington faces serious threats to forest health. Decades of fire suppression and past management practices that changed the species and structure of these forests have put them at higher risk of damage by disease, insects and wildfire.
Publication Type: Report
An Evaluation of Fire Regime Reconstruction Methods
Year: 2014
Ecological restoration is a practice that seeks to heal degraded ecosystems by reestablishing native species, structural characteristics, and ecological processes. The Society for Ecological Restoration International defines ecological restoration as “an intentional activity that initiates or accelerates the recovery of an ecosystem with respect to its health, integrity and sustainability….Restoration attempts to return an ecosystem to its historic trajectory” (Society for Ecological Restoration International Science and Policy Working Group 2004). Most frequent-fire forests throughout the…
Publication Type: Report
Beyond reducing fire hazard: fuel treatment impacts on overstory tree survival
Year: 2014
Fuel treatment implementation in dry forest types throughout the western United States is likely to increase in pace and scale in response to increasing incidence of large wildfires. While it is clear that properly implemented fuel treatments are effective at reducing hazardous fire potential, there are ancillary ecological effects that can impact forest resilience either positively or negatively depending on the specific elements examined, as well as treatment type, timing, and intensity. In this study, we use overstory tree growth responses, measured seven years after the most common fuel…
Publication Type: Journal Article
Contemporary forest restoration: A review emphasizing function
Year: 2014
The forest restoration challenge (globally 2 billion ha) and the prospect of changing climate with increasing frequency of extreme events argues for approaching restoration from a functional and landscape perspective. Because the practice of restoration utilizes many techniques common to silviculture, no clear line separates ordinary forestry practices from restoration. The distinction may be that extra-ordinary activities are required in the face of degraded, damaged, or destroyed ecosystems. Restoration is driven by the desire to increase sustainability of ecosystems and their services and…
Publication Type: Journal Article
Western Spruce Budworm Outbreaks Did Not Increase Fire Risk Over the Last Three Centuries: A Dendrochronological Analysis of Inter-Disturbance Synergism
Year: 2014
Insect outbreaks are often assumed to increase the severity or probability of fire occurrence through increased fuel availability, while fires may in turn alter susceptibility of forests to subsequent insect outbreaks through changes in the spatial distribution of suitable host trees. However, little is actually known about the potential synergisms between these natural disturbances. Assessing inter-disturbance synergism is challenging due to the short length of historical records and the confounding influences of land use and climate changes on natural disturbance dynamics. We used…
Publication Type: Journal Article
Projected Future Changes in Vegetation in Western North America in the Twenty-First Century
Year: 2013
Rapid and broad-scale forest mortality associated with recent droughts, rising temperature, and insect outbreaks has been observed over western North America (NA). Climate models project additional future warming and increasing drought and water stress for this region. To assess future potential changes in vegetation distributions in western NA, the Community Earth System Model (CESM) coupled with its Dynamic Global Vegetation Model (DGVM) was used under the future A2 emissions scenario. To better span uncertainties in future climate, eight sea surface temperature (SST) projections provided…
Publication Type: Journal Article
Swiss Needle Cast
Year: 2013
Since the 1990s, there has been an epidemic of SNC affecting hundreds of thousands of acres of coastal Douglas-fir forests in Oregon, Washington and British Columbia. This constitutes one of the largest foliage-disease epidemics of conifers in North America. SNC is also a localized problem in many inland areas of the west, especially in Montana, Idaho, British Columbia, Washington, and Oregon.
Publication Type: Report
Assessing tree health
Year: 2011
Healthy trees are beneficial to our environment and our property values - but how do we determine if a tree is healthy? This publication briefly discusses common tree health problems and outlines a procedure for assessing tree conditions and getting diagnoses and recommendations from tree health professionals.
Publication Type: Report
A Tale of Two Cedars: International Symposium on Western Redcedar and Yellow-Cedar
Year: 2010
From May 24-28, 2010, an international symposium on western redcedar (Thuja plicata) and yellow-cedar (Callitropsis nootkatensis [syn. Chamaecyparis nootkatensis]) was held at the University of Victoria on Vancouver Island in British Columbia, Canada. The symposium was entitled “A Tale of Two Cedars” and brought together local, regional, national, and international experts to present cultural, biological, management and economic information on the two species. Although some papers or posters focused on just one of the cedars, many of the presenters covered both species and discussed the…
Publication Type: Report
Reducing Fire Risk on Your Forest Property
Year: 2010
Whether you own a few acres or thousands, this publication will help you reduce the potential for wildfire damage on your property while improving overall forest health and wildlife habitat. Although these actions won’t prevent a wildfire from coming onto your property, they can make it more fire resistant. In other words, by following the guidelines in this publication you can reduce a fire’s severity so that most trees survive and firefighters are better able to attack and extinguish the blaze. While this publication provides suggestions for making your property more fire-resistant, it does…
Publication Type: Report