Research Database
Displaying 21 - 40 of 96
Future climate risks from stress, insects and fire across US forests
Year: 2022
Forests are currently a substantial carbon sink globally. Many climate change mitigation strategies leverage forest preservation and expansion, but rely on forests storing carbon for decades to centuries. Yet climate-driven disturbances pose critical risks to the long-term stability of forest carbon. We quantify the climate drivers that influence wildfire and climate stress-driven tree mortality, including a separate insect-driven tree mortality, for the contiguous United States for current (1984–2018) and project these future disturbance risks over the 21st century. We find that current…
Publication Type: Journal Article
Disturbance and Sustainability in Forests of the Western United States
Year: 2021
This report assesses recent forest disturbance in the Western United States and discusses implications for sustainability. Individual chapters focus on fire, drought, insects, disease, invasive plants, and socioeconomic impacts. Disturbance data came from a variety of sources, including the Forest Inventory and Analysis program, Forest Health Protection, and the National Interagency Fire Center. Disturbance trends with the potential to affect forest sustainability include altera-tions in fire regimes, periods of drought in some parts of the region, and increases in invasive plants, insects,…
Publication Type: Journal Article
Disturbance refugia within mosaics of forest fire, drought, and insect outbreaks
Year: 2020
Disturbance refugia – locations that experience less severe or frequent disturbances than the surrounding landscape – provide a framework to highlight not only where and why these biological legacies persist as adjacent areas change but also the value of those legacies in sustaining biodiversity. Recent studies of disturbance refugia in forest ecosystems have focused primarily on fire, with a growing recognition of important applications to land management. Given the wide range of disturbance processes in forests, developing a broader understanding of disturbance refugia is important for…
Publication Type: Journal Article
Estimating Price Dynamics in the Aftermath of Forest Disturbances: The Biscuit Fire in Southwest Oregon
Year: 2020
Catastrophic forest disturbances, such as wildfires, insect outbreaks, and hurricanes, have become more frequent in recent decades. Such disturbances can create supply disruptions in regional timber markets, with potentially significant short-run and long-run price effects. We review the time-series intervention models that have been used to analyze the impacts of forest disturbances. We apply the intervention models to investigate the market effects of the Biscuit Fire that burned nearly 500,000 acres (202,000 hectares) of forest land in southwest Oregon in 2002, thus creating an unexpected…
Publication Type: Journal Article
Invasive grasses: A new perfect storm for forested ecosystems?
Year: 2020
Exotic grasses are a widespread set of invasive species that are notable for their ability to significantly alter key aspects of ecosystem function. Understanding the role and importance of these invaders in forested landscapes has been limited but is now rising, as grasses from Eurasia and Africa continue to spread through ecosystems of the Americas, Australia, and many Pacific islands, where they threaten biodiversity and alter various aspects of the fire regime. The ecological, social and economic impacts of the grass-fire cycle associated with species such as cheatgrass (Bromus tectorum)…
Publication Type: Journal Article
Climate, Environment, and Disturbance History Govern Resilience of Western North American Forests
Year: 2019
Before the advent of intensive forest management and fire suppression, western North American forests exhibited a naturally occurring resistance and resilience to wildfires and other disturbances. Resilience, which encompasses resistance, reflects the amount of disruption an ecosystem can withstand before its structure or organization qualitatively shift to a different basin of attraction. In fire-maintained forests, resilience to disturbance events arose primarily from vegetation pattern-disturbance process interactions at several levels of organization. Using evidence from 15 ecoregions,…
Publication Type: Journal Article
Prescribed fire regimes subtly alter ponderosa pine forest plant community structure
Year: 2019
Prescribed fire is an active management tool used to address wildfire hazard and ecological concerns associated with fire exclusion and suppression over the past century. Despite widespread application in the United States, there is considerable inconsistency and lack of information regarding the extent to which specific outcomes are achieved and under what prescribed fire regimes, particularly in regard to ecological goals related to plant community structure. We quantify differences and patterns in plant functional group abundance, species richness and diversity, and other key forest…
Publication Type: Journal Article
A System Dynamics Model Examining Alternative Wildfire Response Policies
Year: 2019
In this paper, we develop a systems dynamics model of a coupled human and natural fire-prone system to evaluate changes in wildfire response policy. A primary motivation is exploring the implications of expanding the pace and scale of using wildfires as a forest restoration tool. We implement a model of a forested system composed of multiple successional classes, each with different structural characteristics and propensities for burning at high severity. We then simulate a range of alternative wildfire response policies, which are defined as the combination of a target burn rate (or…
Publication Type: Journal Article
Recent post-wildfire salvage logging benefits local and landscape floral and bee communities
Year: 2018
Understanding the implications of shifts in disturbance regimes for plants and pollinators is essential for successful land management. Wildfires are essential natural disturbances that are important drivers of forest biodiversity, and there is often pressure to respond to wildfire with management like post-wildfire logging (i.e., removal of dead trees for economic value immediately following wildfire). We investigated how local floral and bee density, species richness, and community composition and dispersion were influenced by post-wildfire logging, and how these effects differed between an…
Publication Type: Journal Article
Reburn in the Rain Shadow
Year: 2018
Wildfires consume existing forest fuels but also leave behind dead shrubs and trees that become fuel to future wildfires. Harvesting firekilled trees is sometimes proposed as an economical approach for reducing future fuels and wildfire severity. Postfire logging, however, is controversial. Some question its fuel reduction benefits and its ecological impacts. David W. Peterson, a research forester with the USDA Forest Service, and his colleagues investigated the long-term effects of postfire logging on woody fuels in 255 coniferous forest stands that burned with high fire severity in 68…
Publication Type: Report
Fuel mass and stand structure 13 years after logging of a severely burned ponderosa pine forest in northeastern Oregon, U.S.A
Year: 2018
Stand structure and fuel mass were measured in 2011, 13 years after logging of a seasonally dry, ponderosa pine-dominated forest that had burned severely in the 1996 Summit Wildfire, Malheur National Forest, northeastern Oregon, U.S.A. Data are compared to those taken one year after post-fire logging (1999), and analyzed in the context of a second fire (Sunshine Fire) that burned through one of the four treatment blocks in 2008. Three treatments were evaluated in a randomized block experiment: unlogged control, commercial harvest (most dead merchantable trees removed), and fuel reduction…
Publication Type: Journal Article
Prescribed fire regimes subtly alter ponderosa pine forest plant community structure
Year: 2018
Prescribed fire is an active management tool used to address wildfire hazard and ecological concerns associated with fire exclusion and suppression over the past century. Despite widespread application in the United States, there is considerable inconsistency and lack of information regarding the extent to which specific outcomes are achieved and under what prescribed fire regimes, particularly in regard to ecological goals related to plant community structure. We quantify differences and patterns in plant functional group abundance, species richness and diversity, and other key forest…
Publication Type: Journal Article
Evidence for scale‐dependent topographic controls on wildfire spread
Year: 2018
Wildfire ecosystems are thought to be self‐regulated through pattern–process interactions between ignition frequency and location, and patterns of burned and recovering vegetation. Yet, recent increases in the frequency of large wildfires call into question the application of self‐organization theory to landscape resilience. Topography represents a stable bottom‐up template upon which fire interacts as both a physical and an ecological process. However, it is unclear how topographic control changes geographically and across spatial scales. We analyzed fire perimeter and topography data from…
Publication Type: Journal Article
Telling Fire’s Story through Narrative and Art
Year: 2017
Modern works by highly skilled narrative authors and artists have become increasingly useful for telling the story of wildland fire in the United States. Using unconventional means—and with partial funding by the Joint Fire Science Program—creative individuals have spawned some colorful and heartfelt messages that convey insightful information about wildland fire, climate, and other elements of nature to an increasingly receptive public. Recent narrative works by well-known authors, such as Stephen J. Pyne, and creative art pieces by well-established and emerging artists have helped depict…
Publication Type: Report
Fires following Bark Beetles: Factors Controlling Severity and Disturbance Interactions in Ponderosa Pine
Year: 2017
Previous studies have suggested that bark beetles and fires can be interacting disturbances, whereby bark beetle–caused tree mortality can alter the risk and severity of subsequent wildland fires. However, there remains considerable uncertainty around the type and magnitude of the interaction between fires following bark beetle attacks, especially in drier forest types such as those dominated by ponderosa pine (Pinus ponderosa Lawson & C. Lawson). We used a full factorial design across a range of factors thought to control bark beetle−fire interactions, including the temporal phase of the…
Publication Type: Journal Article
Impacts of lodgepole pine dwarf mistletoe (Arceuthobium americanum) infestation on stand structure and fuel load in lodgepole pine dominated forests in central Colorado
Year: 2017
Parasitic plants are capable of causing substantial alterations to plant communities through impacts on individual host plants. Lodgepole pine dwarf mistletoe is an important parasite in forests of the western USA that causes reductions to productivity and is thought to alter wildland fuel complexes. These impacts are hypothesized to vary with infestation severity. To test this, we used a linear mixed modeling approach to evaluate the relationship between dwarf mistletoe infestation severity and parameters representing stand structure and surface and canopy fuels in infested lodgepole pine…
Publication Type: Journal Article
Relational risk assessment and management: investigating capacity in wildfire response networks
Year: 2017
Failures in effective communication and coordination within the network of responding organizations and agencies during a wildfire can lead to problematic or dangerous outcomes. Although risk assessment and management concepts are usually understood with regards to biophysical attributes in the wildfire context, these concepts can be extended to understanding risk for problematic communication and coordination embedded within social and organizational relationships. In this research, we propose leveraging existing network and social coordination theory to investigate how pre-fire…
Publication Type: Report
The Science of Fuel Treatments
Year: 2017
High fuel loads can significantly contribute to the intensity and severity of fires. Fuels include plant material, such as leaves, bark, needles, branches, and vegetation. Land managers use various methods to reduce fuel levels. The two most common fuel treatment methods include forest thinning and prescribed fire. The pace of implementing such fuel treatments has increased over the last several decades. Scientific studies of fuel treatments supported by the Joint Fire Science Program (JFSP) highlight significant findings on the effectiveness of these treatments in various fuel types.
Publication Type: Report
Fire and dwarf mistletoe (Viscaceae: Arceuthobium species) in western North America: contrasting Arceuthobium tsugense and Arceuthobium americanum
Year: 2017
Dwarf mistletoes (Viscaceae: Arceuthobium spp.) and fire interact in important ways in the coniferous forests of western North America. Fire directly affects dwarf mistletoes by killing the host, host branch, or heating/smoking the aerial shoots and fruits. Fire is a primary determinant of dwarf mistletoe distribution on the landscape, and time since fire controls many aspects of dwarf mistletoe epidemiology. Conversely, dwarf mistletoes can influence fire by causing changes in forest composition, structure, and fuels. Prescribed fire is important for management of dwarf mistletoes, while…
Publication Type: Journal Article
Policy Scenarios for fire-adapted communities: Understanding stakeholder risk-perceptions, using Fuzzy Cognitive Maps
Year: 2017
Collaborative groups are most effective when the varied stakeholder groups within them understand the risks of wildfire and take proactive steps to manage these risks. Implementing policies for fire risk mitigation and adaptation, however, remains difficult because risks and policy alternatives are not understood or supported uniformly across diverse stakeholders. To facilitate greater understanding and collaboration across diverse groups, we developed a novel approach, based on Fuzzy Cognitive Maps (FCM), in which we systematically collected mental model representations from a range of…
Publication Type: Report