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Full-Text Articles in Life Sciences

Forest Composition Change And Biophysical Climate Feedbacks Across Boreal North America, Richard Massey, Brendan M. Rogers, Logan T. Berner, Sol Cooperdock, Michelle C. Mack, Xanthe J. Walker, Scott J. Goetz Oct 2023

Forest Composition Change And Biophysical Climate Feedbacks Across Boreal North America, Richard Massey, Brendan M. Rogers, Logan T. Berner, Sol Cooperdock, Michelle C. Mack, Xanthe J. Walker, Scott J. Goetz

Aspen Bibliography

Deciduous tree cover is expected to increase in North American boreal forests with climate warming and wildfire. This shift in composition has the potential to generate biophysical cooling via increased land surface albedo. Here we use Landsat-derived maps of continuous tree canopy cover and deciduous fractional composition to assess albedo change over recent decades. We find, on average, a small net decrease in deciduous fraction from 2000 to 2015 across boreal North America and from 1992 to 2015 across Canada, despite extensive fire disturbance that locally increased deciduous vegetation. We further find near-neutral net biophysical change in radiative forcing associated …


Regeneration Strategies And Forest Resilience To Changing Fire Regimes: Insights From A Goldilocks Model, Tanjona Ramiadantsoa, Zak Ratajczak, Monica G. Turner Mar 2023

Regeneration Strategies And Forest Resilience To Changing Fire Regimes: Insights From A Goldilocks Model, Tanjona Ramiadantsoa, Zak Ratajczak, Monica G. Turner

Aspen Bibliography

Disturbances are ubiquitous in ecological systems, and species have evolved a range of strategies to resist or rebound following disturbance. Understanding how the presence and complementarity of regeneration traits will affect community responses to disturbance is increasingly urgent as disturbance regimes shift beyond their historical ranges of variability. We define "disturbance niche" as a species' fitness across a range of disturbance sizes and frequencies that can reflect the fundamental or realized niche, that is, whether the species occurs alone or with other species. We developed a model of intermediate complexity (i.e., a Goldilocks model) to infer the disturbance niche. We …


Knobcone Pine Response To Shading From Competing Chaparral Shrubs Following Stand-Replacing Wildfire, Sean T. Lindley Jan 2023

Knobcone Pine Response To Shading From Competing Chaparral Shrubs Following Stand-Replacing Wildfire, Sean T. Lindley

Cal Poly Humboldt theses and projects

In northern California, fire regimes are shifting towards more frequent and larger severe wildfire. There is growing concern that this shift poses a threat to biodiversity in the form of cover type change at the landscape scale, resulting in the extirpation of some species in favor of +AD617:AD649well-adapted ones. In northern California, mature serotinous conifers, such as knobcone pine (Pinus attenuata), and resprouting shrub species easily regenerate in severe patches of any size. There is no general consensus regarding the effects of shrub competition on conifer recruitment; conifer response varies with shade tolerance and other abiotic factors. Knobcone …


Factors Contributing To Legacy Hardwood Mortality Following Prescribed Fire, Heather D. Rickard Jan 2023

Factors Contributing To Legacy Hardwood Mortality Following Prescribed Fire, Heather D. Rickard

Cal Poly Humboldt theses and projects

Interruption of Indigenous stewardship has resulted in hardwood decline along what is now known as the middle Klamath River in northern California related to adverse effects to Tribal food sovereignty and community wellbeing. The survivors of a “legacy” of Indigenous stewardship are highly valued by the Karuk and neighboring Tribes for a myriad of culturally beneficial ecological associations and sources of traditional staple foods. Prescribed fire, following a century of fire exclusion, has resulted in unanticipated mortality of legacy tanoak (Notholithocarpus densiflorus), California black oak (Quercus kelloggii), and madrone (Arbutus menziesii), warranting further investigation. …


Facilitation Differentially Affects Competitive Responses Of Aspen And Subalpine Fir Through Stages Of Stand Development, Rebecca Lee Molinari, Matthew F. Bekker, Benjamin D. St. Clair, Jason Bartholomew, R. Justin Derose, Stanley G. Kitchen, Samuel B. St. Clair Mar 2022

Facilitation Differentially Affects Competitive Responses Of Aspen And Subalpine Fir Through Stages Of Stand Development, Rebecca Lee Molinari, Matthew F. Bekker, Benjamin D. St. Clair, Jason Bartholomew, R. Justin Derose, Stanley G. Kitchen, Samuel B. St. Clair

Aspen Bibliography

Spatial interactions between trees influence forest community succession. The objective of this study was to investigate how shifts in forest composition and proximity between tree species affect stand development over time in mixed forest systems. At six locations across the Fishlake National Forest, Utah, USA, in stands where facilitation has been documented previously, tree-ring samples were collected from aspen and subalpine fir trees. Basal area increment was calculated to characterize the effects of the proximity of overstory trees on multidecadal growth responses of aspen and subalpine fir in aspen-dominant and mixed aspen–conifer stands. Subalpine fir seedlings were established next to …


A Comparison Of Wildfire Adaptive Traits In Juvenile Conifers Of The Northern Rockies, Andie Sonnen Jan 2022

A Comparison Of Wildfire Adaptive Traits In Juvenile Conifers Of The Northern Rockies, Andie Sonnen

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Wildfire is an importance disturbance that continues to shape the ecosystems of the northern Rockies through varying patterns of frequency and intensity. Due to historical fire suppression and the hotter and drier conditions brought upon by anthropogenic climate change, wildfire frequency and intensity is increasing. These increases will alter vegetation structure and composition, but the degree to which is unknown.

Individual plant traits can offer insight into how these vegetation communities will shift, especially the particular traits that reduce fire-related mortality. To survive wildfires, juvenile northern conifers employ two strategies: increasing their bark thickness and increasing their crown height. To …


Future Dominance By Quaking Aspen Expected Following Short-Interval, Compounded Disturbance Interaction, Robert A. Andrus, Sarah J. Hart, Niko Tutland, Thomas T. Veblen Jan 2021

Future Dominance By Quaking Aspen Expected Following Short-Interval, Compounded Disturbance Interaction, Robert A. Andrus, Sarah J. Hart, Niko Tutland, Thomas T. Veblen

Aspen Bibliography

The spatial overlap of multiple ecological disturbances in close succession has the capacity to alter trajectories of ecosystem recovery. Widespread bark beetle outbreaks and wildfire have affected many forests in western North America in the past two decades in areas of important habitat for native ungulates. Bark beetle outbreaks prior to fire may deplete seed supply of the host species, and differences in fire‐related regeneration strategies among species may shift the species composition and structure of the initial forest trajectory. Subsequent browsing of postfire tree regeneration by large ungulates, such as elk (Cervus canadensis), may limit the capacity …


Long-Term Effectiveness Of Fuel Treatments In Oak And Chaparral Stands Of Northern California, Caroline Ann Martorano Jan 2019

Long-Term Effectiveness Of Fuel Treatments In Oak And Chaparral Stands Of Northern California, Caroline Ann Martorano

Cal Poly Humboldt theses and projects

Fuel reduction treatments are broadly implemented to reduce the risk of extreme wildfire. Yet, research on the long-term effectiveness and ecological consequences among these treatments is lacking. In this study, I examined short- and long-term changes in fuels and understory vegetation after treatment in chaparral and oak-dominated stands of Whiskeytown National Recreation Area. Treatments included mastication and spring burning, spring burning only, mastication only, and hand-thinning. Treatments were applied randomly to 1 to 2 units within each of 10 blocks. Two plots were established in each treatment unit and fuel and vegetation data was collected and analyzed at the block …


Evaluating Post-Fire Plantation Restoration In A Mixed Conifer Forest In The Sierra Nevada, Iris C. Allen Jan 2019

Evaluating Post-Fire Plantation Restoration In A Mixed Conifer Forest In The Sierra Nevada, Iris C. Allen

Graduate Theses, Dissertations, and Problem Reports

Forests in the western United States have experienced a shift from historical disturbance regimes in the past century. Many of these changes were induced by European settlers logging the forests and suppressing fires. In the past, the dry mixed conifer forests of California’s Sierra Nevada mountains experience frequent, low to mixed severity fires. This fire regime helped maintain a heterogeneous landscape comprised of groups of trees and openings. However, due to fire suppression and high grading logging, forest structure has changed; there are less openings and more small, fire-intolerant trees that can carry a fire into the forests crown. The …


Fire And Road Disturbance Impacts On Forest Plant Species And Seed Rain In Table Mountain Fire Arai, Kittitas County, Washington, Jonathan A. Betz Jan 2019

Fire And Road Disturbance Impacts On Forest Plant Species And Seed Rain In Table Mountain Fire Arai, Kittitas County, Washington, Jonathan A. Betz

All Master's Theses

Forest communities are in a constant state of change. Disturbance events can alter the physical landscape and create conditions favorable to some species while negatively impacting others. Fire has been a natural, reoccurring source of disturbance in Pacific Northwest forests. Over the past centuries the fire paradigm has changed in favor of fire suppression. Forest roads permit access provide greater access but further fracture forest community’s continuity. The 2012 Table Mountain Fire and road influence have altered the plant community’s seed rain and vegetation. This study measured dispersed seeds and understory vegetation cover as functions of roads and fire intensity. …


Beyond The 1984 Perspective: Narrow Focus On Modern Wildfire Trends Underestimates Future Risks To Water Security, Brendan P. Murphy, Larissa L. Yocom, Patrick Belmont Oct 2018

Beyond The 1984 Perspective: Narrow Focus On Modern Wildfire Trends Underestimates Future Risks To Water Security, Brendan P. Murphy, Larissa L. Yocom, Patrick Belmont

Ecology Center Publications

The western United States remains well below historical wildfire activity, yet misconceptions abound in the public and news media that the area burning by wildfire each year in the American West is unprecedented. We submit that short‐term records of wildfire and a disproportionate focus on recent fire trends within high‐profile science stoke these misconceptions. Furthermore, we highlight serious risks to long‐term water security (encompassing water supply, storage, and quality) that have only recently been recognized and are underestimated as the result of skewed perspectives of wildfire. Compiling several data sets, we illustrate a comprehensive history of western wildfire, demonstrate that …


Assessing The Effects Of Climate Change And Fuel Treatments On Forest Dynamics And Wildfire In Dry Mixed-Conifer Forests Of The Inland West: Linking Landscape And Social Perspectives, Brooke Alyce Cassell Mar 2018

Assessing The Effects Of Climate Change And Fuel Treatments On Forest Dynamics And Wildfire In Dry Mixed-Conifer Forests Of The Inland West: Linking Landscape And Social Perspectives, Brooke Alyce Cassell

Dissertations and Theses

Over the past century in the western United States, warming has produced larger and more severe wildfires than previously recorded. General circulation models and their ensembles project continued increases in temperature and the proportion of precipitation falling as rain. Warmer and wetter conditions may change forest successional trajectories by modifying rates of vegetation establishment, competition, growth, reproduction, and mortality. Many questions remain regarding how these changes will occur across landscapes and how disturbances, such as wildfire, may interact with changes to climate and vegetation. Forest management is used to proactively modify forest structure and composition to improve fire resilience. Yet, …


Assessment Of Vegetation Response To Wildfire At Bandelier National Monument, New Mexico: Case Study Of The Las Conchas Fire, Gladys Valentin-Gonzalez Dec 2017

Assessment Of Vegetation Response To Wildfire At Bandelier National Monument, New Mexico: Case Study Of The Las Conchas Fire, Gladys Valentin-Gonzalez

Geography ETDs

In the past couple of decades, there has been an increase in the occurrence of wildfire events in the United States. The U.S. Forest Service estimates that over 73,000 wildfires on average occur annually in the U.S., burning about 7.3 million acres of land. Bandelier National Monument, in northern New Mexico, has been affected by several wildfires in the past 40 years, one of the most recent being the Las Conchas Fire in 2011, which burned over 60,700 hectaresin Bandelier National Monument and Valles Caldera National Preserve. This research explores a remote-sensing based assessment of vegetation response to and recovery …


Fire And Fuels: Vegetation Change Over Time In The Zuni Mountains, New Mexico, Luke Wylie May 2016

Fire And Fuels: Vegetation Change Over Time In The Zuni Mountains, New Mexico, Luke Wylie

Master's Theses

The Zuni Mountains are a region that has been dramatically changed by human interference. Anthropogenically, fire suppression practices have allowed a buildup of fuels and caused a change in the fire-adapted ponderosa pine ecosystem such that the new ecosystem now incorporates many fire-intolerant species. As a result, the low-severity fires that the ecosystem once depended on to regenerate the forest are much reduced, and these low-severity fires are now replaced by crown-level infernos that threaten the forest and nearby towns. In order to combat these effects, land managers are implementing fuel reduction practices and are striving to better understand the …


Natural Disturbances And The Physiognomy Of Pine Savannas : A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet Sep 2012

Natural Disturbances And The Physiognomy Of Pine Savannas : A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet

Frank S. Gilliam

Abstract. Question: The decline of the Pinus palustris ecosystems has resulted from anthropogenic influences, such as conversion to pine plantation forestry, agriculture and land development, all of which are closely related to increases in human populations. Other effects, however, have arisen from alterations in disturbance regimes that maintain the structure and function of these ecosystems. How have alterations of the disturbance regime altered the physiognomy of ‘old-growth’ stands, and what are the implications for ecosystem conservation and restoration? Methods: In contrast to models that emphasize close interactions among the vertically complex strata, we develop a conceptual phenomenological model for the …


Conservation And Restoration Of The Pinus Palustris Ecosystem, Frank S. Gilliam, William J. Platt Sep 2012

Conservation And Restoration Of The Pinus Palustris Ecosystem, Frank S. Gilliam, William J. Platt

Frank S. Gilliam

The well-documented decline of the Pinus palustris ecosystem has resulted from several anthropogenic influences, such as forest clearing (e.g. pine plantation forestry, agriculture) and urban development, both of which are closely related to increases in human populations. Other impacts have arisen from alterations in disturbance regimes responsible for maintaining the structure and function of these ecosystems. Restoration and management of degraded pine savanna ecosystems is critical. Identification of ecological processes that determine the structure and function of the intact system are important because successful restoration efforts should be based on sound scientific understanding. In this paper, we introduce this special …


Fire History And Forest Structural Change In The Spring Mountains, Scott R. Abella Jan 2008

Fire History And Forest Structural Change In The Spring Mountains, Scott R. Abella

Public Policy and Leadership Faculty Publications

Since early 2006 we have been working to develop a partnership with the Spring Mountains District of the Humboldt-Toiyabe National Forest to provide science support for understanding fire history and forest structural changes in support of ecologically based management strategies. We teamed up with the Ecological Restoration Institute (ERI) at Northern Arizona University and the University of Arizona Tree Ring Lab to deliver a workshop on March 6, 2008 at the interagency office in Las Vegas, Nevada. On September 16-18, we again teamed up with colleagues at ERI to conduct a preliminary field assessment of forest change at 10 sites …


Conservation And Restoration Of The Pinus Palustris Ecosystem, Frank S. Gilliam, William J. Platt May 2006

Conservation And Restoration Of The Pinus Palustris Ecosystem, Frank S. Gilliam, William J. Platt

Biological Sciences Faculty Research

The well-documented decline of the Pinus palustris ecosystem has resulted from several anthropogenic influences, such as forest clearing (e.g. pine plantation forestry, agriculture) and urban development, both of which are closely related to increases in human populations. Other impacts have arisen from alterations in disturbance regimes responsible for maintaining the structure and function of these ecosystems. Restoration and management of degraded pine savanna ecosystems is critical. Identification of ecological processes that determine the structure and function of the intact system are important because successful restoration efforts should be based on sound scientific understanding. In this paper, we introduce this special …


Natural Disturbances And The Physiognomy Of Pine Savannas : A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet May 2006

Natural Disturbances And The Physiognomy Of Pine Savannas : A Phenomenological Model, Frank S. Gilliam, William J. Platt, Robert K. Peet

Biological Sciences Faculty Research

Abstract. Question: The decline of the Pinus palustris ecosystems has resulted from anthropogenic influences, such as conversion to pine plantation forestry, agriculture and land development, all of which are closely related to increases in human populations. Other effects, however, have arisen from alterations in disturbance regimes that maintain the structure and function of these ecosystems. How have alterations of the disturbance regime altered the physiognomy of ‘old-growth’ stands, and what are the implications for ecosystem conservation and restoration?

Methods: In contrast to models that emphasize close interactions among the vertically complex strata, we develop a conceptual phenomenological model for the …


Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff Jan 2005

Severe Wind And Fire Regimes In Northern Forests: Historic Variability At The Regional Scale, Lisa A. Schulte-Moore, David J. Mladenoff

Lisa A. Schulte Moore

Within the northern Great Lakes region, mesoscale (10s to 100s of km2) forest patterning is driven by disturbance dynamics. Using original Public Land Survey (PLS) records in northern Wisconsin, USA, we study spatial patterns of wind and fire disturbances during the pre-Euroamerican settlement period (ca. 1850). Our goals were: (1) to determine how effectively wind and fire disturbance can be econstructed from the PLS, (2) to assess the roles of wind and fire in shaping vegetation patterns, (3) to evaluate landscape to regional controls of wind and fire regimes, and (4) to assess the potential for interactions between these disturbances. …


Population Dynamics In Response To Fire In Quercus Laevis - Pinus Palustris Barrens And Related Communities In Southeast Virginia, Allen E. Plocher Apr 1993

Population Dynamics In Response To Fire In Quercus Laevis - Pinus Palustris Barrens And Related Communities In Southeast Virginia, Allen E. Plocher

Biological Sciences Theses & Dissertations

Permanent plots in the Zuni Pine Barrens (Isle of Wight Co., Virginia) were sampled in order to: quantify plant population dynamics in response to fire, compare these dynamics among different moisture regimes, compare the effect of mechanical understory removal to that of fire on tree seedling and herbaceous dynamics, and determine the effect of dense lichen (Cladonia spp.) coverage on pine seedling establishment and survival. Fire resulted in 40% aboveground mortality in the overstory, 80% in the sapling/large shrub layer, and nearly 100% in the understory, followed by a 3.3 to 10.6 fold increase in understory density. Regeneration …


Fire Effects In Northeastern Forests: Aspen, C. Rouse Jan 1986

Fire Effects In Northeastern Forests: Aspen, C. Rouse

Aspen Bibliography

No abstract provided.