Restoring Mixed-conifer Forests with Fire and Mechanical Thinning PDF Download
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Author: Jessica Rae Miesel
Publisher:
ISBN:
Category : Conifers
Languages : en
Pages : 190
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Book Description
Abstract: The forests of northern California experienced frequent, low-intensity fire prior to Euro-American settlement, but more than a century of grazing, logging and fire suppression has resulted in changes in tree community structure that contribute to infrequent, high-intensity fires in these forests today. Although ecosystem restoration for reduction of wildfire hazard has received substantial attention in recent years, many ecological questions remain unanswered. For example, it is not yet clear how large-scale forest manipulations, such as reduction of tree density via forest thinning or prescribed fire, differentially affect soil fertility, nor how impacts on soil nutrient availability in turn affect forest productivity. My research in the Klamath National Forest of northern California investigates the impacts of experimental restoration treatments (prescribed fire, mechanical thinning, and their combination) on soil physical, chemical and microbial parameters and forest floor C and N content, and the time lag and duration of response of leaf nutrient concentrations of two dominant tree species to each treatment. Results showed that significant differences existed among treatments in terms of soil nutrient status and microbial activity, with the effect of fire either mediated or enhanced by thinning; however, for most variables the magnitude of effect was small. Prescribed fire had different effects on soil nutrients and microbial activity in unthinned areas than in areas that had been mechanically thinned prior to fire, and the species composition of trees that remain following thinning significantly affected soil nutrient availability and forest floor C and N content. Thinning also affected conifer needle nutrient concentration and size whereas fire alone does not, and the time since treatment as well as the magnitude and direction of response differed between tree species and among treatments. These results provide an intermediate-term evaluation of the effects of fire and thinning on soil and vegetation, and increase understanding of the link between the above- and belowground components of a mixed-conifer ecosystem. This study contributes to an ecosystem-level understanding of forest restoration strategies, and provides information that is directly applicable to fire and forest management policies in the western United States.
Author: Jessica Rae Miesel
Publisher:
ISBN:
Category : Conifers
Languages : en
Pages : 190
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Book Description
Abstract: The forests of northern California experienced frequent, low-intensity fire prior to Euro-American settlement, but more than a century of grazing, logging and fire suppression has resulted in changes in tree community structure that contribute to infrequent, high-intensity fires in these forests today. Although ecosystem restoration for reduction of wildfire hazard has received substantial attention in recent years, many ecological questions remain unanswered. For example, it is not yet clear how large-scale forest manipulations, such as reduction of tree density via forest thinning or prescribed fire, differentially affect soil fertility, nor how impacts on soil nutrient availability in turn affect forest productivity. My research in the Klamath National Forest of northern California investigates the impacts of experimental restoration treatments (prescribed fire, mechanical thinning, and their combination) on soil physical, chemical and microbial parameters and forest floor C and N content, and the time lag and duration of response of leaf nutrient concentrations of two dominant tree species to each treatment. Results showed that significant differences existed among treatments in terms of soil nutrient status and microbial activity, with the effect of fire either mediated or enhanced by thinning; however, for most variables the magnitude of effect was small. Prescribed fire had different effects on soil nutrients and microbial activity in unthinned areas than in areas that had been mechanically thinned prior to fire, and the species composition of trees that remain following thinning significantly affected soil nutrient availability and forest floor C and N content. Thinning also affected conifer needle nutrient concentration and size whereas fire alone does not, and the time since treatment as well as the magnitude and direction of response differed between tree species and among treatments. These results provide an intermediate-term evaluation of the effects of fire and thinning on soil and vegetation, and increase understanding of the link between the above- and belowground components of a mixed-conifer ecosystem. This study contributes to an ecosystem-level understanding of forest restoration strategies, and provides information that is directly applicable to fire and forest management policies in the western United States.
Author:
Publisher:
ISBN:
Category : Forest health
Languages : en
Pages : 6
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Book Description
Author: Anne M. Rosenthal
Publisher:
ISBN:
Category : Sierra Nevada (Calif. and Nev.)
Languages : en
Pages : 6
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Book Description
Author: Maxwell Odland
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Fire suppression in the western United States has significantly altered forest composition and structure, resulting in higher risk from fire and large-scale drought and bark beetle events. Mechanical thinning and prescribed fire are common treatments designed to reduce high-severity fire risk, but few studies have tracked long-term understory plant community response with repeated fire application that emulates historic fire regimes. We evaluate changes in understory plant community diversity and composition and environmental characteristics over two decades following a factorial field experiment that crosses thinning and two applications of prescribed fire at the Teakettle Experimental Forest (TEF) in the southern Sierra Nevada. We compare experimental fuels treatments against nearby old-growth, mixed-conifer forests with frequent, low severity fire regimes in Yosemite and Kings Canyon National Parks. This study points to key differences in how thinning and prescribed fire treatments affect plant understory diversity. Although local understory plant richness initially increased most following thinning combined with prescribed fire, this treatment did not generate understory communities similar to those in reference forests; Intense shrub growth resulted in low understory evenness and beta diversity over time, which a secondary burn treatment did not alter. Burning without thinning retained a more heterogeneous understory over time and, at least in the two years following the second burn treatment, with high understory richness and evenness similar to reference forest understories. Our results suggest management treatments may need to focus on creating heterogeneity in burn effects and environmental conditions to foster diverse forest understories and limit post-treatment shrub cover.
Author:
Publisher:
ISBN:
Category : Forest fires
Languages : en
Pages : 38
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Book Description
Author: David Lawrence Peterson
Publisher:
ISBN:
Category : Forest fires
Languages : en
Pages : 42
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Book Description
Fire, in conjunction with landforms and climate, shapes the structure and function of forests throughout the Western United States, where millions of acres of forest lands contain accumulations of flammable fuel that are much higher than historical conditions owing to various forms of fire exclusion. The Healthy Forests Restoration Act mandates that public land managers assertively address this situation through active management of fuel and vegetation. This document synthesizes the relevant scientific knowledge that can assist fuel-treatment projects on national forests and other public lands and contribute to National Environmental Policy Act (NEPA) analyses and other assessments. It is intended to support science-based decisionmaking for fuel management in dry forests of the Western United States at the scale of forest stands (about 1 to 200 acres). It highlights ecological principles that need to be considered when managing forest fuel and vegetation for specific conditions related to forest structure and fire hazard. It also provides quantitative and qualitative guidelines for planning and implementing fuel treatments through various silvicultural prescriptions and surfacefuel treatments. Effective fuel treatments in forest stands with high fuel accumulations will typically require thinning to increase canopy base height, reduce canopy bulk density, reduce canopy continuity, and require a substantial reduction in surface fuel through prescribed fire or mechanical treatment or both. Long-term maintenance of desired fuel loadings and consideration of broader landscape patterns may improve the effectiveness of fuel treatments.
Author: Nancy Langston
Publisher: University of Washington Press
ISBN: 0295989688
Category : History
Languages : en
Pages : 405
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Book Description
Across the inland West, forests that once seemed like paradise have turned into an ecological nightmare. Fires, insect epidemics, and disease now threaten millions of acres of once-bountiful forests. Yet no one can agree what went wrong. Was it too much management—or not enough—that forced the forests of the inland West to the verge of collapse? Is the solution more logging, or no logging at all? In this gripping work of scientific and historical detection, Nancy Langston unravels the disturbing history of what went wrong with the western forests, despite the best intentions of those involved. Focusing on the Blue Mountains of northeastern Oregon and southeastern Washington, she explores how the complex landscapes that so impressed settlers in the nineteenth century became an ecological disaster in the late twentieth. Federal foresters, intent on using their scientific training to stop exploitation and waste, suppressed light fires in the ponderosa pinelands. Hoping to save the forests, they could not foresee that their policies would instead destroy what they loved. When light fires were kept out, a series of ecological changes began. Firs grew thickly in forests once dominated by ponderosa pines, and when droughts hit, those firs succumbed to insects, diseases, and eventually catastrophic fires. Nancy Langston combines remarkable skills as both scientist and writer of history to tell this story. Her ability to understand and bring to life the complex biological processes of the forest is matched by her grasp of the human forces at work—from Indians, white settlers, missionaries, fur trappers, cattle ranchers, sheep herders, and railroad builders to timber industry and federal forestry managers. The book will be of interest to a wide audience of environmentalists, historians, ecologists, foresters, ranchers, and loggers—and all people who want to understand the changing lands of the West.
Author: Zachary J. Wenderott
Publisher:
ISBN:
Category : Abies concolor
Languages : en
Pages : 54
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Book Description
Forests throughout much of the western United States are experiencing increasing climatic variability, often resulting in decreased forest productivity and elevated likelihood of tree mortality. Severe drought, such California’s recent 2012-2015 drought, are projected to increase in intensity, frequency, and severity throughout much of this region in coming years. Forest management has long relied on prescribed fire and mechanical thinning to reduce fuel loads and ameliorate potential fire hazards. These treatments may also have the ability to reduce stand density, alleviate competitive pressures, and allow residual trees access to critical resources during periods of extreme stress. Utilizing a long-term National Park Service fire monitoring program allowed us to analyze the effects of prescribed fire treatments on radial growth response in a mixed-conifer forest of northern California. Tree core samples were collected and analyzed from 136 yellow pine (ponderosa pine (Pinus ponderosa) and Jeffrey pine (Pinus jeffreyi)) and 136 white fir (Abies concolor) trees within Lassen Volcanic National Park. Tree-ring data was used to describe factors that influenced tree growth during the locally identified low moisture period (2007 - 2015), as well the potential ability of treatments to improve tree drought resistance and subsequent recovery. Radial growth was positively associated with crown ratio and annual precipitation totals, and negatively associated with localized competitive pressures. Within treatment sites, where stand density was effectively reduced, trees showed improved annual radial growth rates. This appeared to be generally driven by overall treatment intensity and its ability to alter forest density. White fir exhibited a stronger growth response to competitive pressures compared to yellow pine; however, radial growth rates were generally driven by the same factors. Drought resistance did not appear to be strongly correlated with competitive pressures, though drought recovery was slightly associated with increased competitive levels. Findings suggests future forest management techniques, such as prescribed fire and thinning, may be beneficial in terms of reducing competitive pressures and improving radial tree growth among residual trees during future more severe drought.
Author: Allison K. Rossman
Publisher:
ISBN:
Category :
Languages : en
Pages : 94
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Book Description
Mechanical thinning and prescribed burning are commonly used to restore dry, mixed-conifer forests that historically experienced frequent fire. Although these treatments successfully reduce fuel loads, their ability to achieve ecological objectives, such as promoting native plant diversity, is less certain. My thesis research examined how temporal and spatial scales of observation and the approach to analyzing scale-dependent data influence our understanding of understory vegetation responses to thinning intensity and burning. I used long-term data on understory species richness from a restoration experiment in central Washington. I found no effect of thinning intensity alone and scale-dependent responses to burning. For example, annual richness increased over time in burned plots, particularly at small spatial scales, suggesting enhanced recruitment from early-established populations and little perennial expansion. I also found that the analytical approach used to address common challenges of large-scale, long-term experiments, such as variation in pre-treatment conditions and the loss of sample units over time, can affect the conclusions drawn from these experiments. However, careful specification of research questions and consideration of data limitations can yield insights into these conclusions. This research highlights long-term ecological benefits of prescribed burning and the need for measurements over time and among spatial scales, as well as the careful evaluation of analytical approaches, to clarify whether fuel-reduction treatments meet the ecological objectives of dry forest restoration.
Author: Stephen F. Arno
Publisher:
ISBN:
Category : Nature
Languages : en
Pages : 272
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Book Description
In Mimicking Nature's Fire, forest ecologists Stephen Arno and Carl Fiedler present practical solutions to the pervasive problem of deteriorating forest conditions in western North America.
