Research Database
Displaying 41 - 58 of 58
Sagebrush steppe recovery after fire varies by development phase of Juniperus occidentalis woodland
Year: 2013
Woodland ecosystems of the world have been changed by land use demands, altered fire regimes, invasive species and climate change. Reduced fire frequency is recognised as a main causative agent for Pinus–Juniperus L. (piñon–juniper) expansion in North American woodlands. Piñon–juniper control measures, including prescribed fire, are increasingly employed to restore sagebrush steppe communities. We compared vegetation recovery following prescribed fire on Phase 2 (mid-succession) and Phase 3 (late-succession) Juniperus occidentalis Hook. (western juniper) woodlands in Oregon. The herbaceous…
Publication Type: Journal Article
Management of cheatgrass fuel loading in the shrub-steppe
Year: 2013
The fire risk experiment was in plant communities that spanned the range of B. tectorum cover. Bromus tectorum cover was grouped into five classes. Each replicate is comprised of 8 to 18 plots in the three lowest B. tectorum cover classes and 2 to 6 plots at the two highest cover classes. A replicate is a collection of plots where the risk of fire was determined as the proportion of plots that burned. Each class has four replicates. We used 176 square plots, 10 m on a side. Two hundred twenty six plots, 10 m on a side, were used to related B. tectorum cover…
Publication Type: Presentation
Conditions favouring Bromus tectorum dominance of endangered sagebrush steppe ecosystems
Year: 2013
Ecosystem invasibility is determined by combinations of environmental variables, invader attributes, disturbance regimes, competitive abilities of resident species and evolutionary history between residents and disturbance regimes. Understanding the relative importance of each factor is critical to limiting future invasions and restoring ecosystems. We investigated factors potentially controlling Bromus tectorum invasions into Artemisia tridentata ssp. wyomingensis communities across 75 sites in the Great Basin. We measured soil texture, cattle grazing intensity, gaps among perennial plants…
Publication Type: Journal Article
Trajectories of change in sagebrush steppe vegetation communities in relation to multiple wildfires
Year: 2012
Repeated perturbations, both biotic and abiotic, can lead to fundamental changes in the nature of ecosystems, including changes in state. Sagebrush steppe communities provide important habitat for wildlife and grazing for livestock. Fire is an integral part of these systems, but there is concern that increased ignition frequencies and invasive species are fundamentally altering them. Despite these issues, the majority of studies of fire effects in systems dominated by Artemisia tridentata wyomingensis have focused on the effects of single burns. The Arid Lands Ecology Reserve (ALE), in south-…
Publication Type: Journal Article
Shrub Seed Banks in Mixed Conifer Forests of Northern California and the Role of Fire in Regulating Abundance
Year: 2012
Understory shrubs play important ecological roles in forests of the western US, but they can also impede early tree growth and lead to fire hazard concerns when very dense. Some of the more common genera (Ceanothus, Arctostaphylos, and Prunus) persist for long periods in the seed bank, even in areas where plants have been shaded out. To determine shrub seed density and investigate the feasibility of managing shrub abundance by regulating the size of the soil seed bank with fire, we sampled the seed bank in 24 mixed conifer forest stands throughout northern California. Twenty stands were…
Publication Type: Journal Article
Cheating Cheatgrass: New research to combat a wily invasive weed
Year: 2012
Cheatgrass and its cousin, red brome, are exotic annual grasses that have invaded and altered ecosystem dynamics in more than 41 million acres of desert shrublands between the Rockies and the Cascade-Sierra chain. A fungus naturally associated with these Bromus species has been found lethal to the plants’ soil-banked dormant seeds. Supported by the Joint Fire Science Program (JFSP), researchers Susan Meyer, Phil Allen, and Julie Beckstead cultured this fungus, Pyrenophora semeniperda, in the laboratory and developed an experimental field application that, in some trials, killed all the…
Publication Type: Report
Fire Effects on the Spatial Patterning of Soil Properties in Sagebrush Steppe, USA: A Meta-Analysis
Year: 2012
Understanding effects of changes in ecological disturbance regimes on soil properties, and capacity of soil properties to resist disturbance, is important for assessing ecological condition. In this meta-analysis, we examined the resilience of surface soil properties and their spatial patterning to disturbance by fire in sagebrush steppe of North America – a biome currently experiencing increases in wildfire due to climate change. We reviewed 39 studies that reported on soil properties for sagebrush steppe with distinct microsite (undershrub and interspace) patterning that was or was not…
Publication Type: Journal Article
Wildfire severity mediates fluxes of plant material and terrestrial invertebrates to mountain streams
Year: 2012
Wildfire effects upon riparian plant community structure, composition, and distribution may strongly influence the dynamic relationships between riparian vegetation and stream ecosystems. However, few studies have examined the influence of fire on these processes. To that end, we compared the quantity and composition of allochthonous inputs of plant material and terrestrial invertebrates among stream tributaries characterized by various degrees of burn severity 5 years post-fire in the Frank Church Wilderness of central Idaho, USA. The magnitude of inputs of coniferous leaf litter to unburned…
Publication Type: Journal Article
The Use of Seedbed Modifications and Wood Chips to Accelerate Restoration of Well Pad Sites in Western Colorado, USA
Year: 2012
Semiarid ecosystems of Western North America are experiencing a boom in natural gas development. However, these systems are slow to recover from the disturbances created. The purpose of this study was to develop improved restoration techniques on natural gas well pads in Western Colorado. This study examined effects and interactions of seedbed modifications, soil amendments, seed mixtures, and seeding methods. The experiment was conducted in pinyon-juniper and semidesert shrub plant communities on five natural gas well pads beginning in 2006. Soil and plant cover data were collected to assess…
Publication Type: Journal Article
Predicting the Occurrence of Downy Brome (Bromus tectorum) in Central Oregon
Year: 2012
Where the nonnative annual grass downy brome proliferates, it has changed ecosystem processes, such as nutrient, energy, and water cycles; successional pathways; and fire regimes. The objective of this study was to develop a model that predicts the presence of downy brome in Central Oregon and to test whether high presence correlates with greater cover. Understory data from the U.S. Department of Agriculture (USDA) Forest Service's Current Vegetation Survey (CVS) database for the Deschutes National Forest, the Ochoco National Forest, and the Crooked River National Grassland were compiled, and…
Publication Type: Journal Article
Short- and medium-term effects of fuel reduction mulch treatments on soil nitrogen availability in Colorado conifer forests
Year: 2012
Mechanical fuel reduction treatments have been implemented on millions of hectares of western North American forests. The redistribution of standing forest biomass to the soil surface by mulching treatments has no ecological analog, and this practice may alter soil processes and forest productivity. We evaluated the effects of mulch addition on soil nitrogen availability at 15 fuel reduction projects in the southern Rocky Mountains and Colorado Plateau regions of Colorado. Mulching treatments removed 38 Mg ha−1 of standing forest biomass on average and added 2– 4 cm of irregular woody…
Publication Type: Journal Article
Grass Seedling Demography and Sagebrush Steppe Restoration
Year: 2012
Seeding is a key management tool for arid rangeland. In these systems, however, seeded species often fail to establish. A recent study in Wyoming big sagebrush steppe suggested that over 90% of seeded native grass individuals die before seedlings emerged. This current study examines the timing and rate of seed germination, seedling emergence, and seedling death related to this demographic bottleneck. We seeded monocultures of two native perennial bunchgrasses, Pseudoroegenaria spicata (Pursh) Á. Löve and Elymus elymoides (Raf.) Swezey, and one introduced bunchgrass, Agropyron desertorum (…
Publication Type: Journal Article
Photo Series for Quantifying Natural Fuels Volume XI : Eastern Oregon Sagebrush - Steppe and Spotted Owl Nesting Habitat in the Pacific Northwest
Year: 2012
Three series of photographs display a range of natural conditions and fuel loadings for sagebrush-steppe types that are ecotonal with grasses, western juniper, and ponderosa pine in eastern Oregon, and one series of photographs displays a range of natural conditions and fuel loadings for northern spotted owl nesting habitat in forest types in Washington and Oregon. Each group of photos includes inventory information summarizing vegetation composition, structure, and loading; woody material loading and density by size class; forest floor depth and loading; and various site characteristics. The…
Publication Type: Report
Moisture desorption in mechanically masticated fuels: effects of particle fracturing and fuelbed compaction
Year: 2012
Mechanical mastication is increasingly used as a wildland fuel treatment, reducing standing trees and shrubs to compacted fuelbeds of fractured woody fuels. One major shortcoming in our understanding of these fuelbeds is how particle fracturing influences moisture gain or loss, a primary determinant of fire behaviour. To better understand fuel moisture dynamics, we measured particle and fuelbed drying rates of masticated Arctostaphylos manzanita and Ceanothus velutinus shrubs, common targets of mastication in fire-prone western USA ecosystems. Drying rates of intact and fractured particles…
Publication Type: Journal Article
Properties affecting the consumption of sound and rotten coarse woody debris in northern Idaho: a preliminary investigation using laboratory fires
Year: 2012
This study evaluates the consumption of coarse woody debris in various states of decay. Samples from a northern Idaho mixed-conifer forest were classified using three different classification methods, ignited with two different ignition methods and consumption was recorded. Intrinsic properties that change with decay were measured including carbon to nitrogen ratio, density, heat content, lignin content, moisture content and surface area-to-volume ratio. Consumption for logs in different stages of decay is reported with characterisation of wood properties. Results indicate very decayed coarse…
Publication Type: Journal Article
Effectiveness of post-fire seeding at the Fitzner-Eberhardt Arid Land Ecology Reserve, Washington
Year: 2011
In August 2007, the Milepost 17 and Wautoma fires burned a combined total of 77,349 acres (31,302 hectares) of the Fitzner-Eberhardt Arid Land Ecology Reserve (ALE), part of the Hanford Reach National Monument administered by the U.S. Fish and Wildlife Service (USFWS) Mid-Columbia National Wildlife Refuge. In 2008, the USFWS implemented a series of seeding and herbicide treatments to mitigate potential negative consequences of these fires, including mortality of native vegetation, invasion of Bromus tectorum (cheatgrass), and soil erosion. Treatments included combinations of seeding (drill…
Publication Type: Report
Consume 3.0 -- A Software Tool for Computing Fuel Consumption
Year: 2009
Knowing when, where and how fire should be applied is critical for land managers planning to use fire prescriptively for land management goals, or allowing fires ignited naturally to burn. Myriad variables need to be taken into consideration to determine how fire will consume different fuels. Consume, version 3.0 is a user-friendly software that incorporates the Fuel Characteristic Classification System (FCCS) to predict fuel consumption, pollutant emissions, and heat release. A flexible tool, Consume 3.0 makes these calculations based on fuel loadings, fuel moisture and other environmental…
Publication Type: Report
Filling in the Blanks for Prescribed Fire in Shrublands: Developing Information to Support Improved Fire Planning
Year: 2009
By collecting information on fuel loading, fuel consumption, fuel moisture, site conditions and fire weather on fires in a variety of shrubland types, researchers are developing a fuller knowledge of shrubland fire effects. Results are being integrated into the software package CONSUME, a user-friendly software tool for predicting fuel consumption and emissions for fire, fuel and smoke management planning. Shrubland types studied include chamise chaparral in California, big sagebrush in Montana, pine flatwoods in Florida and Georgia, and pitch pine scrub in the New Jersey Pinelands.…
Publication Type: Report