Research Database
Displaying 101 - 120 of 145
U.S. federal fire and forest policy: emphasizing resilience in dry forests
Year: 2016
Current U.S. forest fire policy emphasizes short-term outcomes versus long-term goals. This perspective drives managers to focus on the protection of high-valued resources, whether ecosystem-based or developed infrastructure, at the expense of forest resilience. Given these current and future challenges posed by wildland fire and because the U.S. Forest Service spent >50% of its budget on fire suppression in 2015, a review and reexamination of existing policy is warranted. One of the most difficult challenges to revising forest fire policy is that agency organizations and decision making…
Publication Type: Journal Article
Managed wildfire effects on forest resilience and water in the Sierra Nevada
Year: 2016
Fire suppression in many dry forest types has left a legacy of dense, homogeneous forests. Such landscapes have high water demands and fuel loads, and when burned can result in catastrophically large fires. These characteristics are undesirable in the face of projected warming and drying in the western US. Alternative forest and fire treatments based on managed wildfire—a regime in which fires are allowed to burn naturally and only suppressed under defined management conditions—offer a potential strategy to ameliorate the effects of fire suppression. Understanding the long-term effects of…
Publication Type: Journal Article
Disturbance, tree mortality, and implications for contemporary regional forest change in the Pacific Northwest
Year: 2016
Tree mortality is an important demographic process and primary driver of forest dynamics, yet there are relatively few plot-based studies that explicitly quantify mortality and compare the relative contribution of endogenous and exogenous disturbances at regional scales. We used repeated observations on 289,390 trees in 3673 1 ha plots on U.S. Forest Service lands in Oregon and Washington to compare distributions of mortality rates among natural disturbances and vegetation zones from the mid-1990s to mid-2000s, a period characterized by drought, insect outbreaks, and large wildfires.…
Publication Type: Journal Article
Patterns of conifer regeneration following high severity wildfire in ponderosa pine - dominated forests of the Colorado Front Range
Year: 2016
Many recent wildfires in ponderosa pine (Pinus ponderosa Lawson & C. Lawson) - dominated forests of the western United States have burned more severely than historical ones, generating concern about forest resilience. This concern stems from uncertainty about the ability of ponderosa pine and other co-occurring conifers to regenerate in areas where no surviving trees remain. We collected post-fire conifer regeneration and other data within and surrounding five 11-18 year-old Colorado Front Range wildfires to examine whether high severity burn areas (i.e., areas without surviving trees)…
Publication Type: Journal Article
Forest disturbance across the conterminous United States from 1985-2012: The emerging dominance of forest decline
Year: 2016
Evidence of shifting dominance among major forest disturbance agent classes regionally to globally has been emerging in the literature. For example, climate-related stress and secondary stressors on forests (e.g., insect and disease, fire) have dramatically increased since the turn of the century globally, while harvest rates in the western US and elsewhere have declined. For shifts to be quantified, accurate historical forest disturbance estimates are required as a baseline for examining current trends. We report annual disturbance rates (with uncertainties) in the aggregate and by major…
Publication Type: Journal Article
Toward a more ecologically informed view of severe forest fires
Year: 2016
We use the historical presence of high-severity fire patches in mixed-conifer forests of the western United States to make several points that we hope will encourage development of a more ecologically informed view of severe wildland fire effects. First, many plant and animal species use, and have sometimes evolved to depend on, severely burned forest conditions for their persistence. Second, evidence from fire history studies also suggests that a complex mosaic of severely burned conifer patches was common historically in the West. Third, to maintain ecological integrity in forests born of…
Publication Type: Journal Article
Scanning the Future of Wildfire: Resilience Ahead...Whether We Like It or Not?
Year: 2016
The field of so-called “futures research” provides researchers and stakeholders in a given subject area or system a way to map out and plan for alternate possible scenarios of the future. A recent research project supported by the Joint Fire Science Program brought together futures researchers and wildfire specialists to envision what the future holds for wildfire impacts and how the wildfire community may respond to the complex suite of emerging challenges. The consensus of the project’s foresight panel suggests that an era of resilience is ahead: but that this resilience may come either…
Publication Type: Report
Fire severity and cumulative disturbance effects in the post-mountain pine beetle lodgepole pine forests of the Pole Creek Fire
Year: 2016
Recent large scale mountain pine beetle (Dendroctonus ponderosae Hopkins, MPB) outbreaks have created concern regarding increased fuel loadings and exacerbated fire behavior and have prompted a desire to understand the effects of sequential disturbances on the landscape. However, previous research has focused on quantifying fuel loadings and using operational fire behavior models, rather than direct field measurements, to understand changes in fire severity following MPB. The 2012 Pole Creek Fire in central Oregon partially occurred in gray stage (8–15 years post-MPB epidemic) lodgepole pine…
Publication Type: Journal Article
Opportunities to utilize traditional phenological knowledge to support adaptive management of social-ecological systems vulnerable to changes in climate and fire regimes
Year: 2016
The field of adaptive management has been embraced by researchers and managers in the United States as an approach to improve natural resource stewardship in the face of uncertainty and complex environmental problems. Integrating multiple knowledge sources and feedback mechanisms is an important step in this approach. Our objective is to contribute to the limited literature that describes the benefits of better integrating indigenous knowledge (IK) with other sources of knowledge in making adaptive-management decisions. Specifically, we advocate the integration of traditional phenological…
Publication Type: Journal Article
Changing disturbance regimes, ecological memory, and forest resilience
Year: 2016
Ecological memory is central to how ecosystems respond to disturbance and is maintained by two types of legacies – information and material. Species life-history traits represent an adaptive response to disturbance and are an information legacy; in contrast, the abiotic and biotic structures (such as seeds or nutrients) produced by single disturbance events are material legacies. Disturbance characteristics that support or maintain these legacies enhance ecological resilience and maintain a “safe operating space” for ecosystem recovery. However, legacies can be lost or diminished as…
Publication Type: Journal Article
Employing resilience in the United States Forest Service
Year: 2016
The concept of resilience has permeated the discourse of many land use and environmental agencies in an attempt to articulate how to develop and implement policies concerned with the social and ecological dimensions of natural disturbances. Several distinct definitions of resilience exist, each with its own concepts, focus and contexts related to land use policy and management. This often makes understanding the inherent objectives of policies and related principles challenging. The United States Forest Service (USFS) is one example where ambiguity and uncertainty surrounding the use of…
Publication Type: Journal Article
Burning the legacy? Influence of wildfire reburn on dead wood dynamics in a temperate conifer forest
Year: 2016
Dynamics of dead wood, a key component of forest structure, are not well described for mixed- severity fi re regimes with widely varying fi re intervals. A prominent form of such variation is when two stand- replacing fi res occur in rapid succession, commonly termed an early- seral “reburn.” These events are thought to strongly infl uence dead wood abundance in a regenerating forest, but this hypothesis has scarcely been tested. We measured dead wood following two overlapping wildfi res in coniferdominated forests of the Klamath Mountains, Oregon (USA), to assess whether reburning (15- yr…
Publication Type: Journal Article
Effects of Drought on Forests and Rangelands in the United States: A Comprehensive Science Synthesis
Year: 2016
This assessment provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA), and it establishes the scientific foundation needed to manage for drought resilience and adaptation. Focal areas include drought characterization; drought impacts on forest processes and disturbances such as insect outbreaks and wildfire; and consequences for forest and rangeland values. Drought can be a severe natural disaster with substantial social and economic consequences. Drought becomes most obvious when large-scale changes are observed;…
Publication Type: Report
Tamm Review: Management of mixed-severity fire regime forests in Oregon, Washington, and Northern California
Year: 2016
Increasingly, objectives for forests with moderate- or mixed-severity fire regimes are to restore successionally diverse landscapes that are resistant and resilient to current and future stressors. Maintaining native species and characteristic processes requires this successional diversity, but methods to achieve it are poorly explained in the literature. In the Inland Pacific US, large, old, early seral trees were a key historical feature of many young and old forest successional patches, especially where fires frequently occurred. Large, old trees are naturally fire-tolerant, but today are…
Publication Type: Journal Article
REVIEW: Searching for resilience: addressing the impacts of changing disturbance regimes on forest ecosystem services
Year: 2016
The provisioning of ecosystem services to society is increasingly under pressure from global change. Changing disturbance regimes are of particular concern in this context due to their high potential impact on ecosystem structure, function and composition. Resilience-based stewardship is advocated to address these changes in ecosystem management, but its operational implementation has remained challenging. We review observed and expected changes in disturbance regimes and their potential impacts on provisioning, regulating, cultural and supporting ecosystem services, concentrating on…
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
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
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
Local Ecological Knowledge and Fire Management: What Does the Public Understand?
Year: 2015
As fire management agencies seek to implement more flexible fire management strategies, local understanding and support for these strategies become increasingly important. One issue associated with implementing more flexible fire management strategies is educating local populations about fire management and identifying what local populations know or do not know related to fire management. This study used survey data from three 2010 wildland fires to understand how ecological knowledge and education level affected fire management perception and understanding. Results indicated that increased…
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