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Articles 31 - 60 of 154
Full-Text Articles in Forest Sciences
Multidecadal Change In Aspen Experiencing Long-Unburned, Mixed-Severity Wildfire, And Reburn Disturbance Regimes, Cerena Brewen
Multidecadal Change In Aspen Experiencing Long-Unburned, Mixed-Severity Wildfire, And Reburn Disturbance Regimes, Cerena Brewen
Cal Poly Humboldt theses and projects
Quaking aspen (Populus tremuloides) is a valued, minor component on western landscapes. It provides a wide range of ecosystem services, and has been in decline for the last century. This decline may be explained partially by the lack of fire on the landscape as aspen benefit from fire that eliminates conifer competition and stimulates reproduction through root suckering. Managers are interested in aspen restoration but have a lack of knowledge about their spatial dynamics in response to fire. Improving our understanding of aspen stand spatial changes over time may be important for maintaining their presence on landscapes where …
Aspen Recruitment In The Yellowstone Region Linked To Reduced Herbivory After Large Carnivore Restoration, Luke E. Painter, Robert L. Beschta, Eric J. Larsen, William J. Ripple
Aspen Recruitment In The Yellowstone Region Linked To Reduced Herbivory After Large Carnivore Restoration, Luke E. Painter, Robert L. Beschta, Eric J. Larsen, William J. Ripple
Aspen Bibliography
Quaking aspen (Populus tremuloides) recruitment during the 1980s–90s was suppressed by Rocky Mountain elk (Cervus canadensis) herbivory on winter ranges in the Yellowstone region, and saplings (young aspen taller than 2 m) were rare. Following the 1995–96 reintroduction of gray wolves (Canis lupus), browsing decreased and sapling recruitment increased in Yellowstone National Park. We compared aspen data from inside the park to data collected in three winter ranges outside the park. For most areas, the percentage of young aspen browsed annually was 80–100% in 1997–98, decreasing to 30–60% in 2011–15. Sapling recruitment was inversely …
Phytochemical Screening Of Quaking Aspen (Populus Tremuloides) Extracts By Uplc-Qtof-Ms And Evaluation Of Their Antimicrobial Activity, Annabelle St-Pierre, Dorian Blondeau, André Lajeunesse, Julien Bley, Nathalie Bourdeau, Isabel Desgagné-Penix
Phytochemical Screening Of Quaking Aspen (Populus Tremuloides) Extracts By Uplc-Qtof-Ms And Evaluation Of Their Antimicrobial Activity, Annabelle St-Pierre, Dorian Blondeau, André Lajeunesse, Julien Bley, Nathalie Bourdeau, Isabel Desgagné-Penix
Aspen Bibliography
The continual emergence of pathogen resistance is a recurring challenge and pushes for the development of antimicrobial compounds. Here, we investigated compounds from quaking aspen trees (Populus tremuloides) as potential antimicrobial agents. Several extractions using different solvents were realized, and corresponding antimicrobial activity was tested against eight microorganisms. Results revealed that polar extraction solvents including water, ethanol and methanol gave the best extraction yields (>15.07%). Minimal inhibition concentration (MIC) and minimal bactericidal/fungicidal concentration (MBC/MFC) demonstrated that water extracts had the best antimicrobial activity by a weak to moderate inhibition of growth of all eight tested microorganisms in addition to …
Reconciling Niches And Neutrality In A Subalpine Temperate Forest, Tucker J. Furniss, Andrew J. Larson, James A. Lutz
Reconciling Niches And Neutrality In A Subalpine Temperate Forest, Tucker J. Furniss, Andrew J. Larson, James A. Lutz
Wildland Resources Faculty Publications
The Unified Neutral Theory of Biodiversity has been put forth to explain species coexistence in forests worldwide, but its assumption of species equivalence has been met with much debate. Theoretical advancements have reconciled the opposing concepts of neutral and niche theories as two ends of a continuum, improving our understanding of global patterns in diversity and community assembly. However, the relative importance of niche and neutral processes remains understudied in temperate forests. To determine the balance of niche and neutral processes in climatically limited subalpine temperate forests, we established the Utah Forest Dynamics Plot, a 13.64-ha plot comprising 27,845 stems …
The Influence Of Aspen Chemistry And The Nutritional Context On Aspen Herbivory, Kristen Y. Heroy
The Influence Of Aspen Chemistry And The Nutritional Context On Aspen Herbivory, Kristen Y. Heroy
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Consumption of aspen by herbivores is one major force causing aspen decline in North America. In this Dissertation, I aimed to determine why herbivores prefer browsing on certain aspen stands over others, and why they prefer consuming aspen that contains chemical defenses over understory forages like grasses, forbs, and shrubs. I explored the influence of nutrients and chemical defenses within aspen on aspen intake and preference by lambs in pen experiments. I also explored drivers of aspen preference on the landscape by looking at relationships between aspen herbivory, indicators of aspen health, amount of nutrients available in the understory, and …
Can Carbon Fluxes Explain Differences In Soil Organic Carbon Storage Under Aspen And Conifer Forest Overstories?, Antra Boča, H. Van Miegroet
Can Carbon Fluxes Explain Differences In Soil Organic Carbon Storage Under Aspen And Conifer Forest Overstories?, Antra Boča, H. Van Miegroet
Wildland Resources Faculty Publications
Climate- and management-induced changes in tree species distributions are raising questions regarding tree species-specific effects on soil organic carbon (SOC) storage and stability. Quaking aspen (Populus tremuloides Michx.) is the most widespread tree species in North America, but fire exclusion often promotes the succession to conifer dominated forests. Aspen in the Western US have been found to store more SOC in the mineral soil than nearby conifers, but we do not yet fully understand the source of this differential SOC accumulation. We measured total SOC storage (0–50 cm), characterized stable and labile SOC pools, and quantified above- and belowground …
A Multiple‐Scale Assessment Of Long‐Term Aspen Persistence And Elevational Range Shifts In The Colorado Front Range, Mario Bretfeld, Scott B. Franklin, Robert K. Peet
A Multiple‐Scale Assessment Of Long‐Term Aspen Persistence And Elevational Range Shifts In The Colorado Front Range, Mario Bretfeld, Scott B. Franklin, Robert K. Peet
Aspen Bibliography
Aspen forests and woodlands are some of the most species‐rich forest communities in the northern hemisphere. Changing climate, altered disturbance regimes, land use, and increased herbivore pressure threaten these forests both in Eurasia and North America. In addition, rapid mortality dubbed “Sudden Aspen Decline” is a concern for aspen's long‐term presence in the western United States, especially Colorado and Utah. Yet it is still unclear whether aspen is persistent or declining at the landscape scale. We assessed aspen persistence at different spatial scales in the Colorado Front Range by resampling 89 plots containing aspen from among 305 vegetation plots sampled …
Year-End Report On Rac Project Entitled "Propagating Aspen Clones: Survival In The 21st Century", Ralph Baierlein
Year-End Report On Rac Project Entitled "Propagating Aspen Clones: Survival In The 21st Century", Ralph Baierlein
Aspen Bibliography
Initial damage caused by wild ungulates was minimal. In August 2013, a large elk pulled off five cones and destroyed three saplings on the exposed, eastern side of the exclosure. Although deer tracks were plentiful in the bare earth of the fire line, there was no evidence that deer had harmed the saplings. The combination of a cone and a mesh sleeve on the exposed saplings sufficed.
Facilitation Drives Mortality Patterns Along Succession Gradients Of Aspen-Conifer Forests, W. John Calder, Samuel B. St. Clair
Facilitation Drives Mortality Patterns Along Succession Gradients Of Aspen-Conifer Forests, W. John Calder, Samuel B. St. Clair
Aspen Bibliography
While it is well established that facilitation and competition are important structuring forces in plant communities, a clear understanding of the interactions between them and how they change through the life stages of plants and affect long-term plant community development is lacking. We have observed that conifer seedlings are rarely found growing in meadows but readily establish under adjacent aspen stands, particularly at the base of aspen trees, creating the potential for antagonistic interactions in later life stages. To examine these relationships and their potential consequences on forest community development, we characterized patterns of establishment, regeneration, and overstory mortality of …
Propagating Trembling Aspen From Root Cuttings: Impact Of Storage Length And Phenological Period Of Root Donor Plants, Jessica Snedden, Simon M. Landhausser, Victor J. Lieffers, Lee R. Charleson
Propagating Trembling Aspen From Root Cuttings: Impact Of Storage Length And Phenological Period Of Root Donor Plants, Jessica Snedden, Simon M. Landhausser, Victor J. Lieffers, Lee R. Charleson
Aspen Bibliography
Two experiments were conducted to examine the effects of growing conditions, duration of cold storage, and distinct phenological periods of root donor plants on the propagation success of aspen rootlings. Root donor plants were produced either under greenhouse or open grown conditions. Root cuttings were periodically collected from donor plants that had been stored for various lengths of time in cold storage (up to 180 days), or that were stored dormant in cold storage (up to 150 days) and then grown for another full growing season. Longer storage of donor plants produced only slightly smaller rootlings and resulted in slightly …
Aspen Biology, Community Classification, And Management In The Blue Mountains, David K. Swanson, Craig L. Schmitt, Diane M. Shirley, Vicky Erickson, Kenneth J. Schuetz, Michael L. Tatum, David C. Powell
Aspen Biology, Community Classification, And Management In The Blue Mountains, David K. Swanson, Craig L. Schmitt, Diane M. Shirley, Vicky Erickson, Kenneth J. Schuetz, Michael L. Tatum, David C. Powell
Aspen Bibliography
Quaking aspen (Populus tremuloides Michx.) is a valuable species that is declining in the Blue Mountains of northeastern Oregon. This publication is a compilation of over 20 years of aspen management experience by USDA Forest Service workers in the Blue Mountains. It includes a summary of aspen biology and occurrence in the Blue Mountains, and a discussion of aspen conservation and management techniques such as fencing, conifer removal, and artificial propagation. Local data on bird use of aspen stands, insects and diseases in aspen, and genetic studies of aspen are also included. An aspen community classification developed from over …
Relationship Of Climate And Growth Of Quaking Aspen (Populus Tremuloides) In Yellowstone National Park, Erik S. Jules, Allyson L. Carroll, Matthew J. Kauffman
Relationship Of Climate And Growth Of Quaking Aspen (Populus Tremuloides) In Yellowstone National Park, Erik S. Jules, Allyson L. Carroll, Matthew J. Kauffman
Aspen Bibliography
Quaking aspen is a widespread tree that is in decline across wide areas of western North America, and is predicted to experience a large range shift if future climate predictions are realized. The purpose of our study was to determine what climate factors have influenced aspen growth in Yellowstone National Park, USA, and to determine whether these climatic influences vary across a heterogeneous landscape. We extracted increment cores from 10-12 aspen in each of 16 stands spread across a 1,526 km2 area. Using ring widths, we created a182-year standardized chronology from 1821 to 2003 A.D. composed of 151 series. We …
Aspen Mortality Summit, December 18 And 19, 2006, Salt Lake City, Utah, Dale L. Bartos, Wayne D. Shepperd
Aspen Mortality Summit, December 18 And 19, 2006, Salt Lake City, Utah, Dale L. Bartos, Wayne D. Shepperd
Aspen Bibliography
The USDA Forest Service Rocky Mountain Research Station sponsored an aspen sum- mit meeting in Salt Lake City, Utah, on December 18 and19, 2006, to discuss the rapidly increasing mortality of aspen (Populus tremuloides) throughout the western United States. Selected scientists, university faculty, and managers from Federal, State, and non-profit agencies with experience working with aspen were invited. Participants were first asked to share information on recent aspen mortality. Subject matter working groups were then asked to determine factors associated with recent aspen mortality, recommend research needs, and organize those needs into testable questions and hypotheses. This report documents their …
Regeneration Of Aspen Following Partial And Strip Understory Protection Harvest In Boreal Mixedwood Forests, Alison D. Lennie, Simon M. Landsausser, Victor J. Lieffers, Derek Sidders
Regeneration Of Aspen Following Partial And Strip Understory Protection Harvest In Boreal Mixedwood Forests, Alison D. Lennie, Simon M. Landsausser, Victor J. Lieffers, Derek Sidders
Aspen Bibliography
Trembling aspen regeneration was studied in 2 types of partial harvest systems designed to harvest mature aspen but pro- tect immature spruce and encourage natural aspen regeneration. Two partial harvest systems, where the residual aspen was either left in strips or was dispersed uniformly, were compared to traditional clearcuts. After the first and second year since harvest, aspen sucker density and growth was similar between the 2 partial harvests, but was much lower than in the clearcuts. However, in the partial cuts the regeneration density was very much dependent on the location relative to residual trees. The density of regeneration …
Aspen Regeneration On Log Decking Areas As Influenced By Season And Duration Of Log Storage, Kevin N. Renkema, Victor J. Lieffers, Simon M. Landhausser
Aspen Regeneration On Log Decking Areas As Influenced By Season And Duration Of Log Storage, Kevin N. Renkema, Victor J. Lieffers, Simon M. Landhausser
Aspen Bibliography
This study assessed aspen regeneration on decking areas as affected by season of log deck building and duration of log storage; as well as root wounding, soil com- paction, and slash depth. On former decking areas that were built after a summer harvest, aspen regeneration was 50% lower and root death 35% greater compared to former decking areas of a fall harvest. Duration of log storage after a fall harvest had little effect on aspen regeneration; short (1.5–3 months) or long (11 months) storage resulted in similar regeneration. Slash load was greatly increased on decking areas while root wounding and …
Species Richness And Soil Properties In Pinus Ponderosa Forests: A Structural Equation Modeling Analysis, Daniel C. Laughlin, Scott R. Abella, W. Wallace Covington, James B. Grace
Species Richness And Soil Properties In Pinus Ponderosa Forests: A Structural Equation Modeling Analysis, Daniel C. Laughlin, Scott R. Abella, W. Wallace Covington, James B. Grace
Public Policy and Leadership Faculty Research
Question: How are the effects of mineral soil properties on understory plant species richness propagated through a network of processes involving the forest overstory, soil organic matter, soil nitrogen, and understory plant abundance? Location: North-central Arizona, USA. Methods: We sampled 75 0.05-ha plots across a broad soil gradient in a Pinus ponderosa (ponderosa pine) forest ecosystem. We evaluated multivariate models of plant species richness using structural equation modeling. Results: Richness was highest at intermediate levels of understory plant cover, suggesting that both colonization success and competitive exclusion can limit richness in this system. We did not detect a reciprocal positive …
Ecology, Biodiversity, Management, And Restoration Of Aspen In The Sierra Nevada, Wayne D. Shepperd, Paul C. Rogers, David Burton, Dale L. Bartos
Ecology, Biodiversity, Management, And Restoration Of Aspen In The Sierra Nevada, Wayne D. Shepperd, Paul C. Rogers, David Burton, Dale L. Bartos
Aspen Bibliography
This report was commissioned by the USDA Forest Service Lake Tahoe Basin Management Unit to synthesize existing information on the ecology and management of aspen (Populus tremuloides) in the Sierra Nevada of California and surrounding environs. It summarizes available information on aspen throughout North America from published literature, internal government agency reports, and experienced scientists and managers. The historic distribution, abundance, and ecologic role of aspen in the Sierra Nevada are discussed, along with the reproductive physiology of aspen. Issues that affect aspen health and vigor in the Sierra Nevada and elsewhere are covered, along with methodology for …
Some Environmental Relationships Of Undergrowth Species In Aspen Communities Of The Intermountain West, W F. Mueggler
Some Environmental Relationships Of Undergrowth Species In Aspen Communities Of The Intermountain West, W F. Mueggler
Aspen Bibliography
This analysis results from an opportunity to explore plant-environmental relationships from data collected for a different purpose. Origin of the data is a study designed to develop an aspen community-type classification for southern Idaho, western Wyoming, Utah, and Nevada which resulted in the publication "Aspen Community Types of the Intermountain Region" GTR INT-250 by W.F. Mueggler (1988).
Sustaining Aspen In Western Landscapes: Symposium Proceedings, Wayne D. Shepperd, Dan Binkley, Dale L. Bartos, Thomas J. Stohlgren, Lane G. Eskew
Sustaining Aspen In Western Landscapes: Symposium Proceedings, Wayne D. Shepperd, Dan Binkley, Dale L. Bartos, Thomas J. Stohlgren, Lane G. Eskew
Aspen Bibliography
No abstract provided.
Aspen Regeneration And Response To Fire In The Intermountain West, Kelly J. Mccloskey
Aspen Regeneration And Response To Fire In The Intermountain West, Kelly J. Mccloskey
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
The history of Populus tremuloides regeneration in the Intermountain West, particularly western Wyoming, is one of prolific vegetative reproduction following wildland fire. The reproductive physiology of aspen and its disturbance-response characteristics are explored through a review of previous studies. The combination of fire suppression and increased herbivory on aspen by wild and domestic ungulates is likely facilitating conifer invasion of areas historically dominated by aspen as has been observed in parts of Wyoming, Utah, and Colorado over the past 100 years. A case study of the regenerative response of aspen to wildland fire in western Wyoming demonstrates how physiology, life …
Toxicity Of Aspen Wood Leachate To Aquatic Life: Laboratory Studies, Barry R. Taylor, J. Stephen Goudey, N. Bruce Carmichael
Toxicity Of Aspen Wood Leachate To Aquatic Life: Laboratory Studies, Barry R. Taylor, J. Stephen Goudey, N. Bruce Carmichael
Aspen Bibliography
Trembling aspen (Populus tremuloides Michx.), a common hardwood tree throughout Canada, is being harvested at increasing rates for use in paper and building materials. Piles of aspen logs have been observed to produce a dark, watery, acutely toxic leachate. A laboratory study was undertaken to elucidate the nature, strength, and persistence of aspen leachate toxicity and the chemical composition of the leachate. Leaching from aspen chips in the laboratory was rapid, with 1% mass loss in the first 24 h. Another 2 weeks of immersion was necessary to remove all remaining leachable material (3% total)> Fresh aspen leachate derived …
Response Of Aspen Root Suckers To Regeneration Methods And Post-Harvest Protection, Wayne D. Shepperd
Response Of Aspen Root Suckers To Regeneration Methods And Post-Harvest Protection, Wayne D. Shepperd
Aspen Bibliography
No abstract provided.
Characterization Of Aspen Isoprene Synthase, An Enzyme Responsible For Leaf Isoprene Emission To The Atmosphere, Gary M. Silver, Ray Fall
Characterization Of Aspen Isoprene Synthase, An Enzyme Responsible For Leaf Isoprene Emission To The Atmosphere, Gary M. Silver, Ray Fall
Aspen Bibliography
Isoprene (2-methyl-1,3-butadiene) is a volatile hydrocarbon emitted from many plant species to the atmosphere, where it plays an important role in atmospheric chemistry. An enzyme extracted from aspen (Populus tremuloides) leaves was previously found to catalyze the Mg2+-dependent elimination of pyrophosphate from dimethylallyl diphosphate (DMAPP) to form isoprene (Silver, G. M., and Fall, R.(1991) Plant Physiol. 97, 1588-1591). This enzyme, isoprene synthase, has now been purified 4000-fold to near homogeneity. The enzyme had a native molecular mass of 98-137 kDa and isoelectric point of 4.7 and contained 58- and 62-kDa subunits, implying that it is a heterodimer. …
Improving Aspen Kraft Pulp By A Novel, Low Technology Fungal Pretreatment, Y.R. Chen, E.L. Schmidt
Improving Aspen Kraft Pulp By A Novel, Low Technology Fungal Pretreatment, Y.R. Chen, E.L. Schmidt
Aspen Bibliography
This study investigated the biopulping agent Phanerochaete chrysosporium with a new process that required neither wood sterilization nor pure culture incubation conditions. Aspen (Populus tremuloides Michaux) chip bales with three treatments were studied. Each bale was kraft cooked after 8.5 weeks of pretreatment. The effects of fungal inoculation and foil-wrapping on pulp and paper strength properties were evaluated. Fungal pretreatment caused significantly faster response to beating as lower freeness was noted. Foil-wrapping retarded the loss of moisture within the bale, and as a result, prolonged fungal activities, resulting in substantial increases in burst strength. Tear was slightly increased, but there …
Carbon Allocation And Partitioning In Aspen Clones Varying In Sensitivity To Tropospheric Ozone, M.D. Coleman, R.E. Dickson, J.G. Isebrands, D.F. Karnosky
Carbon Allocation And Partitioning In Aspen Clones Varying In Sensitivity To Tropospheric Ozone, M.D. Coleman, R.E. Dickson, J.G. Isebrands, D.F. Karnosky
Aspen Bibliography
No abstract provided.
Parent Stand Age And Harvesting Treatment Effects On Juvenile Aspen Biomass Productivity, H. Grewal
Parent Stand Age And Harvesting Treatment Effects On Juvenile Aspen Biomass Productivity, H. Grewal
Aspen Bibliography
No abstract provided.
Quaking Aspen Productivity Recovers After Repeated Prescribed Fire, Donald A. Perala
Quaking Aspen Productivity Recovers After Repeated Prescribed Fire, Donald A. Perala
Aspen Bibliography
No abstract provided.
Cankers On Western Quaking Aspen, David W. Johnson, Jerome S. Beatty, Thomas E. Hinds
Cankers On Western Quaking Aspen, David W. Johnson, Jerome S. Beatty, Thomas E. Hinds
Aspen Bibliography
No abstract provided.
Sixty Years Of Change In Tree Numbers And Basal Area In Central Utah Aspen Stands, Walter F. Mueggler
Sixty Years Of Change In Tree Numbers And Basal Area In Central Utah Aspen Stands, Walter F. Mueggler
Aspen Bibliography
No abstract provided.
Fungi Associated With Sprout Mortality In Aspen Clearcuts In Colorado And Arizona, W.R. Jacobi, W.D. Shepperd
Fungi Associated With Sprout Mortality In Aspen Clearcuts In Colorado And Arizona, W.R. Jacobi, W.D. Shepperd
Aspen Bibliography
Four aspen stands with greater than 90% sprout mortality in Colorado and one in Arizona were evaluated for fungal pathogens. There 4- to 5-year-old sprouts had rapidly expanding cankers moving from the terminal to the ground line. Roots of sampled sprouts showed no damage and root diseases were not found. Fruiting structures of Cytospora chrysosperma were consistently found on dying stems, while those of Dothiora polyspora were occasionally found. The same organisms were isolated from the margins of advancing cankers. Pathogenicity tests using greenhouse-grown aspen trees indicated C. chrysosperma caused rapidly expanding cankers similar to those observed on the aspen …