Research Database
Displaying 1 - 20 of 20
Long-term soil nutrient and understory plant responses to post-fire rehabilitation in a lodgepole pine forest
Year: 2025
Wildfires and other disturbances play a fundamental role in regenerating lodgepole pine forests. Though severe, stand-replacing fires are typical of this ecosystem, they can have dramatic impacts on soil properties and biogeochemical processes that influence the rate and composition of vegetation recovery. Organic soil amendments are often applied to manage post-fire erosion, but they can also improve soil moisture and nutrient retention and potentially alter the trajectory of post-fire revegetation. We compared change in soil nutrients, microbial communities, and understory plant cover and…
Publication Type: Journal Article
Fire severity drives understory community dynamics and the recovery of culturally significant plants
Year: 2024
Anthropogenic influences are altering fire regimes worldwide, resulting in an increase in the size and severity of wildfires. Simultaneously, throughout western North America, there is increasing recognition of the important role of Indigenous fire stewardship in shaping historical fire regimes and fire-adapted ecosystems. However, there is limited understanding of how ecosystems are affected by or recover from contemporary “megafires,” particularly in terms of understory plant communities that are critical to both biodiversity and Indigenous cultures. To address this gap, our collaborative…
Publication Type: Journal Article
Broadcast burning has persistent, but subtle, effects on understory composition and structure: Results of a long-term study in western Cascade forests
Year: 2024
Approaches to forest management have changed markedly in the Pacific Northwest in recent decades, yet legacies of past management persist on the landscape. Following clearcut logging, woody residues were typically burned to reduce future fire hazard, create planting spots, facilitate natural recruitment, and retard growth of competing vegetation. We asked whether legacies of broadcast burning persist in the forest understory during the early stages of stand closure, how they manifest structurally or compositionally, whether they are altered by subsequent management (pre-commercial thinning),…
Publication Type: Journal Article
Long-term frequent fire and cattle grazing alter dry forest understory vegetation
Year: 2024
Understanding fire and large herbivore interactions in interior western forests is critical, owing to the extensive and widespread co-occurrence of these two disturbance types and multiple present and future implications for forest resilience, conservation and restoration. However, manipulative studies focused on interactions and outcomes associated with these two disturbances are rare in forested rangelands. We investigated understory vegetation response to 5-year spring and fall prescribed fire and domestic cattle grazing exclusion in ponderosa pine stands and reported long-term responses,…
Publication Type: Journal Article
Prescribed fire after thinning increased resistance of sub-Mediterranean pine forests to drought events and wildfires
Year: 2023
Vegetation structure affects the vulnerability of a forest to drought events and wildfires. Management decisions, such as thinning intensity and type of understory treatment, influence competition for water resources and amount of fuel available. While heavy thinning effectively reduces tree water stress and intensity of a crown fire, the duration of these benefits may be limited by a fast growth response of the understory. Our aim was to study the effect of forest structure on pine forests vulnerability to extreme drought events and on the potential wildfire behaviour after management, with…
Publication Type: Journal Article
Burn severity and pre-fire seral state interact to shape vegetation responses to fire in a young, western Cascade Range forest
Year: 2022
Wildfire size and frequency are increasing across the western U.S., affecting large areas of young, second-growth forest originating after logging and burning. Despite their prevalence in the western Cascade landscape, we have a poor understanding of how these young stands respond to fire or how their responses differ from older, undisturbed forests, which are well studied. We explore these questions using pre- and early post-fire data from a young (<30-year-old), naturally regenerating forest in western Oregon that was burned preemptively to limit spread of the 2018 Terwilliger Fire. We…
Publication Type: Journal Article
Post-fire Salvage Logging Science Series
Year: 2021
The publications and media in this hot topic address the effects of salvage logging on plants, biodiversity, and cavity-nesting birds. They also cover a range of research that includes, but is not limited to, the ecological impacts of salvage logging; the effects of salvage logging on soil, sediment production, mountain pine beetles, and riparian systems.
Publication Type: Presentation
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
Understory vascular plant responses to retention harvesting with and without prescribed fire
Year: 2019
Wildfire is the predominant natural disturbance in the boreal forests of western Canada. Natural disturbance-based forest management involves the use of retention harvesting to retain stand structural diversity post-harvest; however, this partial harvesting technique does not cause combustion of the forest floor as does fire. Application of prescribed burning to areas treated with retention harvesting might emulate the influence of wildfires more effectively than harvesting alone. We compared understory vascular plant diversity, abundance, and composition between forest stands subjected to…
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
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
The effects of thinning and burning on understory vegetation in North America: A meta-analysis
Year: 2017
Management in fire-prone ecosystems relies widely upon application of prescribed fire and/or fire-surrogate (e.g., forest thinning) treatments to maintain biodiversity and ecosystem function. The literature suggests fire and mechanical treatments proved more variable in their effects on understory vegetation as compared to their effects on stand structure. The growing body of work comparing fire and thinning effects on understory vegetation offers an opportunity to increase the generality of conclusions through meta-analysis. We conducted a meta-analysis to determine if there were consistent…
Publication Type: Journal Article
Positive effects of fire on birds may appear only under narrow combinations of fire severity and time-since-fire
Year: 2016
We conducted bird surveys in 10 of the first 11 years following a mixed-severity fire in a dry, low-elevation mixed-conifer forest in western Montana, United States. By defining fire in terms of fire severity and time-since-fire, and then comparing detection rates for species inside 15 combinations of fire severity and time-since-fire, with their rates of detection in unburned (but otherwise similar) forest outside the burn perimeter, we were able to assess more nuanced effects of fire on 50 bird species. A majority of species (60%) was detected significantly more frequently inside than…
Publication Type: Journal Article
Post-fire logging produces minimal persistent impacts on understory vegetation in northeastern Oregon, USA
Year: 2016
Post-fire forest management commonly requires accepting some negative ecological impacts from management activities in order to achieve management objectives. Managers need to know, however,whether ecological impacts from post-fire management activities are transient or cause long-term ecosystem degradation. We studied the long-term response of understory vegetation to two post-fire loggingtreatments – commercial salvage logging with and without additional fuel reduction logging – on a long-term post-fire logging experiment in northeastern Oregon, USA. We sampled understory plant coverand…
Publication Type: Journal Article
Response of understory vegetation to salvage logging following a high-severity wildfire
Year: 2016
Timber is frequently salvage-logged following high-severity stand-replacing wildfire, but the practice is controversial. One concern is that compound disturbances could result in more deleterious impacts than either disturbance individually, with mechanical operations having the potential to set back recovering native species and increase invasion by non-native species. Following the 2002 Cone Fire on the Lassen National Forest, three replicates of five salvage treatments were applied to 15 units formerly dominated by ponderosa pine, covering a range of disturbance intensities from unsalvaged…
Publication Type: Journal Article
Vegetation Response to Burn Severity, Native Grass Seeding, and Salvage Logging
Year: 2015
As the size and extent of wildfires has increased in recent decades, so has the cost and extent of post-fire management, including seeding and salvage logging. However, we know little about how burn severity, salvage logging, and post-fire seeding interact to influence vegetation recovery long-term. We sampled understory plant species richness, diversity, and canopy cover one to six years post fire (2006 to 2009, and 2011) on 72 permanent plots selected in a stratified random sample to define post-fire vegetation response to burn severity, post-fire seeding with native grasses, and salvage…
Publication Type: Journal Article
Modeling the direct effect of salvage logging on long-term temporal fuel dynamics in dry-mixed conifer forests
Year: 2015
Salvage logging has been proposed to reduce post-fire hazardous fuels and mitigate re-burn effects, but debate remains about its effectiveness when considering fuel loadings are dynamic, and re-burn occurrence is stochastic, in time. Therefore, evaluating salvage loggings capacity to reduce hazardous fuels requires estimating fuel loadings in unmanipulated and salvaged stands over long time periods. We sampled for snag dynamics, decomposition rates, and fuel loadings within unmanipulated high-severity portions of 7 fires, spanning a 24-year chronosequence, in dry-mixed conifer forests of…
Publication Type: Journal Article
Post-fire logging reduces surface woody fuels up to four decades following wildfire
Year: 2015
Severe wildfires create pulses of dead trees that influence future fuel loads, fire behavior, and fire effects as they decay and deposit surface woody fuels. Harvesting fire-killed trees may reduce future surface woody fuels and related fire hazards, but the magnitude and timing of post-fire logging effects on woody fuels have not been fully assessed. To address this issue, we sampled surface woody fuels within 255 coniferous forest stands that burned with high fire severity in 68 wildfires between 1970 and 2007 in eastern Washington and Oregon, USA. Sampling included 96 stands that were…
Publication Type: Journal Article
Effects of post-fire salvage logging and a skid trail treatment on ground cover, soils, and sediment production in the interior western United States
Year: 2015
Post-fire salvage logging adds another set of environmental effects to recently burned areas, and previous studies have reported varying impacts on vegetation, soil disturbance, and sediment production with limited data on the underlying processes. Our objectives were to determine how: (1) ground-based post-fire logging affects surface cover, soil water repellency, soil compaction, and vegetative regrowth; (2) different types of logging disturbance affect sediment production at the plot and small catchment (“swale”) scales; and (3) applying logging slash to skid trails affects soil properties…
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