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• 1. [Article] CEO 1 ; An Illustrated Guide to Fire in Central Oregon Forests

  This pictorial guide is primarily intended to serve as a backdrop for field tours of central Oregon that involve topics surrounding wildland fire. It also is designed to provide an overview of the role ...

  Citation × Citation Citation Abstract Copy Title: CEO 1 ; An Illustrated Guide to Fire in Central Oregon Forests Author: Tappeiner, J. C. (John C.), Eckert, Bradley E., Walstad, John D., Oregon State University. Forest Research Laboratory This pictorial guide is primarily intended to serve as a backdrop for field tours of central Oregon that involve topics surrounding wildland fire. It also is designed to provide an overview of the role of fire in the major ecosystems characteristic of this region. Topics covered include fire history, fire regimes, current fire conditions, fire behavior, fire threats to natural resources, fuel treatments, interactions with the public, and future challenges and management options. A list of key references and glossary are also included. Title: CEO 1 ; An Illustrated Guide to Fire in Central Oregon Forests Author: Tappeiner, J. C. (John C.), Eckert, Bradley E., Walstad, John D., Oregon State University. Forest Research Laboratory This pictorial guide is primarily intended to serve as a backdrop for field tours of central Oregon that involve topics surrounding wildland fire. It also is designed to provide an overview of the role of fire in the major ecosystems characteristic of this region. Topics covered include fire history, fire regimes, current fire conditions, fire behavior, fire threats to natural resources, fuel treatments, interactions with the public, and future challenges and management options. A list of key references and glossary are also included. Close

• 2. [Article] The effects of natural fire and recreational disturbance on montane forest ecosystem composition, structure and nitrogen dynamics, Crater Lake National Park, Oregon

  Disturbance, whether natural or of human origin, modifies to varying degrees many ecosystem attributes. Fire is a natural process in the montane forests of southern Oregon but for much of the 20th century ...

  Citation × Citation Citation Abstract Copy Title: The effects of natural fire and recreational disturbance on montane forest ecosystem composition, structure and nitrogen dynamics, Crater Lake National Park, Oregon Author: Wilson, John K. (John Kevin) Disturbance, whether natural or of human origin, modifies to varying degrees many ecosystem attributes. Fire is a natural process in the montane forests of southern Oregon but for much of the 20th century fire was viewed as an apocalypse and thus fervently suppressed. Effective natural resource management requires an understanding of how ecosystems function, including the ecological response to the natural disturbance regime or anthropogenically altered conditions. To describe the effects of natural fire and ecosystem changes with time following fire, I examined plant composition, structure, biomass and soil nitrogen using a chronosequence of sites ranging in age from 1 to >300 years. The ecological importance of human activity is a function of the magnitude and permanence of its effects which were described at active and abandoned recreation sites. Stand-replacing fires killed virtually 100% of the overstory trees, consumed 87% of the forest floor and resulted in a 27% loss in total aboveground biomass. A pulse of mineralized nitrogen was still apparent 2 years following fire. Two years following fire, little plant colonization was established. The availability of local seed sources, particularly seedbanking species, appears to have been an important determinant of the early-successional community composition. The developing community was dominated by nitrogen-fixing species which may play an important role in the post-fire nitrogen dynamics in these ecosystems. Conifer seedling densities measured 667 individuals/ha 8 years following fire and 1714 individuals/ha 24 years after fire. Extended tree maturation and variation in composition characterized the forest structure and composition during secondary succession. Total aboveground biomass remained high and accumulation followed a general U-shaped curve. Recreational use resulted in a reduction in tree density and biomass at all active sites. The greatest reductions occurred at sites set in late-successional forests. Compositional change was also greatest at sites established in late-successional forest with increased dominance of lodgepole pine and graminoids. Within 40 years the abandoned, mid-successional sites had recovered from most of the recreational impacts; however 40 years was not sufficient for late-successional forest recovery. These results suggest that the stage of succession should be considered when assessing potential recreational impacts. Title: The effects of natural fire and recreational disturbance on montane forest ecosystem composition, structure and nitrogen dynamics, Crater Lake National Park, Oregon Author: Wilson, John K. (John Kevin) Disturbance, whether natural or of human origin, modifies to varying degrees many ecosystem attributes. Fire is a natural process in the montane forests of southern Oregon but for much of the 20th century fire was viewed as an apocalypse and thus fervently suppressed. Effective natural resource management requires an understanding of how ecosystems function, including the ecological response to the natural disturbance regime or anthropogenically altered conditions. To describe the effects of natural fire and ecosystem changes with time following fire, I examined plant composition, structure, biomass and soil nitrogen using a chronosequence of sites ranging in age from 1 to >300 years. The ecological importance of human activity is a function of the magnitude and permanence of its effects which were described at active and abandoned recreation sites. Stand-replacing fires killed virtually 100% of the overstory trees, consumed 87% of the forest floor and resulted in a 27% loss in total aboveground biomass. A pulse of mineralized nitrogen was still apparent 2 years following fire. Two years following fire, little plant colonization was established. The availability of local seed sources, particularly seedbanking species, appears to have been an important determinant of the early-successional community composition. The developing community was dominated by nitrogen-fixing species which may play an important role in the post-fire nitrogen dynamics in these ecosystems. Conifer seedling densities measured 667 individuals/ha 8 years following fire and 1714 individuals/ha 24 years after fire. Extended tree maturation and variation in composition characterized the forest structure and composition during secondary succession. Total aboveground biomass remained high and accumulation followed a general U-shaped curve. Recreational use resulted in a reduction in tree density and biomass at all active sites. The greatest reductions occurred at sites set in late-successional forests. Compositional change was also greatest at sites established in late-successional forest with increased dominance of lodgepole pine and graminoids. Within 40 years the abandoned, mid-successional sites had recovered from most of the recreational impacts; however 40 years was not sufficient for late-successional forest recovery. These results suggest that the stage of succession should be considered when assessing potential recreational impacts. Close

• 3. [Article] Dead fuels and understory vegetation six years after a large mixed-severity wildfire in southwest Oregon

  Though the mixed-evergreen forests of the Klamath Siskiyous have a long history of large, mixed-severity fires, most research in this region has concentrated on the impacts of high-severity fire. Knowledge ...

  Citation × Citation Citation Abstract Copy Title: Dead fuels and understory vegetation six years after a large mixed-severity wildfire in southwest Oregon Author: Nathanson, Amy Though the mixed-evergreen forests of the Klamath Siskiyous have a long history of large, mixed-severity fires, most research in this region has concentrated on the impacts of high-severity fire. Knowledge of the ecological effects of low- and moderate-severity areas within mixed-severity fires is important because such areas may account for over half the landscape affected by a fire. The purpose of this study was to understand the relationship of fire severity with dead fuels and understory vegetation across a full range of fire severities. Study sites were located within and just outside the boundary of the 2002 Biscuit Fire, which burned 200,000 hectares in a mosaic of burn severities. Six years after the Biscuit Fire, the biomass and depth of litter and duff was lower on burned sites than unburned sites, and lowest on high-severity sites. This relationship was reversed for woody fuels >7.62 cm in diameter, where quantities were highest in high- and extreme-severity areas, though there was no evidence that quantities differed between low-severity and unburned sites. There was no evidence of a relationship between woody fuels 0.64-7.62 cm in diameter and fire severity, 6 years post-fire. There was no evidence that fuel quantities differed between sites that burned only in the Biscuit Fire with sites that also burned 15 years earlier in the 1987 Silver Fire. Fuel quantities and composition differed between burned and unburned sites, but these differences disappeared if litter and duff were not considered. Fuel classes were correlated with each other within three general size classes: small (litter, duff, and fuels <2.54 cm), medium (fuels 2.54-30 cm), and large (fuels >30 cm). There was little correlation between these size classes. Vegetation response also varied by fire severity, species, and height. Generally, density for tree seedlings <0.5 m was highest on low-severity sites and lowest on high-severity sites. For seedlings 0.5-1.37 m the relationship was reversed, with the highest seedling densities in high-severity areas. Specific seedling relationships to burn severity and other explanatory factors (e.g. shrub cover, elevation, precipitation, maxiumun August temperatures) varied by species and seedling height. Average seedling densities were above the minimum acceptable stocking levels of 333 trees per hectare (135 seedlings/acre) as identified in federal plans for the fire area. Shrub species richness and diversity did not vary with burn severity; however, shrub species and ground cover composition did differ with burn severity six years after the Biscuit Fire. The relationship of understory cover composition with burn severity aligned with species life history traits; fire-adapted, nitrogen-fixing species were more prevalent on high- and extreme-severity sites while species associated with low-severity fire or old-growth forests were more prevalent on low-severity or unburned sites. I found no evidence of difference in total graminoid or forb cover based on fire severity, but shrub quantities were lower on low-severity sites than on unburned, high-, and extreme-severity sites. This study reveals how fuel and vegetation vary across the full range of fire severities. It demonstrates that mixed-severity fires create a mix of ecological responses. It also provides a baseline for future studies, as the relationships between fire severity and fuels or vegetation may disappear or change in subsequent decades. Title: Dead fuels and understory vegetation six years after a large mixed-severity wildfire in southwest Oregon Author: Nathanson, Amy Though the mixed-evergreen forests of the Klamath Siskiyous have a long history of large, mixed-severity fires, most research in this region has concentrated on the impacts of high-severity fire. Knowledge of the ecological effects of low- and moderate-severity areas within mixed-severity fires is important because such areas may account for over half the landscape affected by a fire. The purpose of this study was to understand the relationship of fire severity with dead fuels and understory vegetation across a full range of fire severities. Study sites were located within and just outside the boundary of the 2002 Biscuit Fire, which burned 200,000 hectares in a mosaic of burn severities. Six years after the Biscuit Fire, the biomass and depth of litter and duff was lower on burned sites than unburned sites, and lowest on high-severity sites. This relationship was reversed for woody fuels >7.62 cm in diameter, where quantities were highest in high- and extreme-severity areas, though there was no evidence that quantities differed between low-severity and unburned sites. There was no evidence of a relationship between woody fuels 0.64-7.62 cm in diameter and fire severity, 6 years post-fire. There was no evidence that fuel quantities differed between sites that burned only in the Biscuit Fire with sites that also burned 15 years earlier in the 1987 Silver Fire. Fuel quantities and composition differed between burned and unburned sites, but these differences disappeared if litter and duff were not considered. Fuel classes were correlated with each other within three general size classes: small (litter, duff, and fuels <2.54 cm), medium (fuels 2.54-30 cm), and large (fuels >30 cm). There was little correlation between these size classes. Vegetation response also varied by fire severity, species, and height. Generally, density for tree seedlings <0.5 m was highest on low-severity sites and lowest on high-severity sites. For seedlings 0.5-1.37 m the relationship was reversed, with the highest seedling densities in high-severity areas. Specific seedling relationships to burn severity and other explanatory factors (e.g. shrub cover, elevation, precipitation, maxiumun August temperatures) varied by species and seedling height. Average seedling densities were above the minimum acceptable stocking levels of 333 trees per hectare (135 seedlings/acre) as identified in federal plans for the fire area. Shrub species richness and diversity did not vary with burn severity; however, shrub species and ground cover composition did differ with burn severity six years after the Biscuit Fire. The relationship of understory cover composition with burn severity aligned with species life history traits; fire-adapted, nitrogen-fixing species were more prevalent on high- and extreme-severity sites while species associated with low-severity fire or old-growth forests were more prevalent on low-severity or unburned sites. I found no evidence of difference in total graminoid or forb cover based on fire severity, but shrub quantities were lower on low-severity sites than on unburned, high-, and extreme-severity sites. This study reveals how fuel and vegetation vary across the full range of fire severities. It demonstrates that mixed-severity fires create a mix of ecological responses. It also provides a baseline for future studies, as the relationships between fire severity and fuels or vegetation may disappear or change in subsequent decades. Close