Genetics and Genomics Commons^™

Timber Harvesting Was The Most Important Factor Driving Changes In Vegetation Composition, As Compared To Climate And Fire Regime Shifts, In The Mixedwood Temperate Forests Of Temiscamingue Since Ad 1830, Daniela Robles, Yan Boulanger, Jesus Pascual, Victor Danneyrolles, Yves Bergeron, Igor Drobyshev

Aspen Bibliography

Context The vegetation composition of northeastern North American forests has significantly changed since pre-settlement times, with a marked reduction in conifer-dominated stands, taxonomic and functional diversity. These changes have been attributed to fire regime shifts, logging, and climate change.

Methods In this study, we disentangled the individual effects of these drivers on the forest composition in southwestern Quebec from 1830 to 2000 by conducting retrospective modelling using the LANDIS-II forest landscape model. The model was run based on pre-settlement forest composition and fire history reconstructions, historical timber harvest records, and climate reanalysis data. We compared counterfactual scenarios excluding individual factors …

Evaluating Elk Distribution And Conflict Under Proposed Management Alternatives At The National Elk Refuge In Jackson, Wyoming, Gavin G. Cotterill, Paul C. Cross, Eric K. Cole, Jonathan D. Cook, Margaret C. Mceachran, Tabitha A. Graves

Aspen Bibliography

We evaluated measurable attributes describing the current and future distribution of Cervus elaphus canadensis (elk) across a region surrounding Jackson, Wyoming, for five feedground management alternatives proposed by the U.S. Fish and Wildlife Service as a revision to 2007 "Bison and Elk Management Plan" of the National Elk Refuge. A resource selection function evaluated measurable attributes of interest to managers, including elk use of private property and sensitive habitat types at monthly timesteps and varying winter conditions. The study area boundaries were created through an expert elicitation process and consist of the Jackson Elk Herd Unit, Grand Teton National Park, …

Increased Positive Tree Species Mixture Effects On The Abundance And Richness Of Collembola With Stand Development In Canadian Boreal Forests, Yakun Zhang, Sai Peng, Zilong Ma, Chen Chen, Bilei Gao, Xinli Chen, Han Y.H. Chen

Aspen Bibliography

It is well established that species mixtures could enhance ecosystem functioning in diverse ecosystem types, with these benefits increasing over time. However, the impact of tree mixtures on Collembola communities following stand development in natural forests remains unclear, despite the critical roles Collembola plays in litter decomposition and nutrient cycling. We investigated the effects of tree species mixtures on Collembola abundance, diversity, and community structure by sampling pure and mixed jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) of 15-year-old and 41-year-old stands in natural boreal forest. In total, 6,620 individuals of Collembola were identified …

Feasibility Of Producing Non-Structural Wood Products Using Trembling Aspen Lumber, Mengyuan Zhang

Aspen Bibliography

Trembling aspen (Populus tremuloides) is abundant in Canada but underutilized in non-structural solid wood products.This study was aimed at evaluating the feasibility of using aspen lumber to produce flooring, moulding, and siding. The shrinkage, surface roughness, and wettability of aspen wood were tested. The surface hardness, screw withdrawal resistance, colour change, and dimensional stability of there products fabricated were examined. The wood yield of each product was analyzed. It was found that aspen showed superior machinability and wettability to silver maple and yellow poplar. Aspen flooring had a Brinell hardness of 13.47 MPa, 60% lower than silver maple. …

Potential Of Using Trembling Aspen To Make Structural Engineered Wood Products, Dawei Wang

Aspen Bibliography

Trembling aspen (Populus tremuloides) is abundant in Canada but is widely considered an underutilized species. This study was aimed at evaluating the potential of using aspen lumber to produce cross-laminated timber (CLT), glued-laminated timber (glulam), and wood I-joists. The key mechanical properties of these engineered wood products, which were fabricated using a modified grading criterion, were examined. It was found that 1) The mean effective bending stiffness and characteristic bending moment resistance of 5-layer CLT specimens in the major-strength direction were 5,069x10⁹ N·mm²/m and 97.65x10⁶ N·mm/m; 2) The mean apparent MOE and characteristic modulus …

Function Over Form: The Benefits Of Aspen As Surrogate Brood-Rearing Habitat For Greater Sage-Grouse, Michel T. Kohl, Charles P. Sandford, Paul C. Rogers, Renee Chi, Terry A. Messmer, David K. Dahlgren

Aspen Bibliography

Species of conservation concern are often habitat specialists, posing significant risk to those species when specific plant communities are threatened. As a result, practitioners habitually focus conservation efforts on these communities while ignoring ecological mechanisms that explain the wildlife–plant relationships. In doing so, practitioners may overlook alternative vegetation communities that could maintain wildlife populations under alternative conditions (e.g., climate change). Here, we term these areas surrogate habitat, defined as vegetation communities or resource sites that provide similar critical resources as conventional sites, and assess their potential for conservation using a case study of greater sage-grouse (Centrocercus urophasianus) on …

Tree Rings Reveal Mixtures Of Aspen And Spruce Exhibit Greater Drought Resilience In A Planted Field Experiment, Jéssica Chaves Cardoso, Linhao Wu, Marcel Schneider, Charles A. Nock

Aspen Bibliography

Boreal forests provide a wealth of ecosystem services, many of which are linked to forest productivity. Climate change is expected to increase the frequency, duration, and severity of drought, and undermine the productivity of western boreal forests. Favouring species mixtures has emerged as a potential strategy to increase forest resilience to drought. To test the hypothesis that mixtures of trembling aspen and white spruce were more productive than pure stands because they were more resistant and resilient to drought, we analyzed community and species responses to drought utilizing measurements of annual growth obtained from stem disc samples from a planted …

Assessing Spatial Distribution And Quantification Of Native Trees In Saskatchewan's Prairie Landscape Using Remote Sensing Techniques, Elham Shafeian, Bryan J. Mood, Kenneth W. Belcher, Colin P. Laroque

Aspen Bibliography

The importance of trees in non-forest landscapes has been the focus of only a few studies. However, these trees provide many important ecosystem services. In this study, we mapped and quantified these trees using Sentinel-2 (S2) and very high-resolution (VHR) Google satellite imagery without any field campaigns. We performed a Random Forest (RF) classification to map the spatial distribution of native trees in different scenarios. The optimal model showed an overall accuracy and kappa of 0.99 and 0.98, respectively. We mapped 40,500 km² of tree cover, including native tree cover (approximately 29,565 km²≈10.5%), excluding plantations, regional and …

Condition And Management Futures In A Quaking Aspen Recreation Area. Final Report To Snyderville Basin Special Recreation District, Paul C. Rogers, Georgie Corkery, Anna B. Miller

Aspen Bibliography

In partnership with Snyderville Basin Special Recreation District (SBSRD), we undertook a study of ecological conditions and user preferences within a quaking aspen recreational destination forest. The location, in two sections know as Run-A-Muk and Right Turn Sage (RAM/RTS), has experienced some forest die-off in the principally aspen dominated forest dissected by ski, bike, and hiking trails. Graduate student Georgie Corkery led the study and successfully completed a Master's degree, in addition to providing needed information to SBSRD regarding the status, uses, and preferred actions at this facility. Key outcomes regarding aspen conditions include assigning causal factors—ungulate browsing and elevated …

Multi-Decadal Aspen Dynamics Show Recruitment Bottleneck Across Complex Mountain Community, Michael T. Stoddard, Kyle C. Rodman, Connor D. Crouch, David W. Huffman, Peter Z. Fulé, Kristen M. Waring, Margaret M. Moore

Aspen Bibliography

Changes in forest structure and shifts in tree species composition have occurred globally due to climate change and altered disturbance regimes. With climate trending toward warmer and drier conditions, these altered forest communities may reorganize in diverse and unpredictable ways. This is especially true in mountain environments where a range of vegetation types and abiotic conditions coexist. In this study, we used long-term permanent plot data from a site spanning broad environmental gradients to assess regeneration and mortality patterns in populations of aspen (Populus tremuloides). The study site, located on the San Francisco Peaks, Arizona, USA, is near …

The Primacy Of Density-Mediated Indirect Effects In A Community Of Wolves, Elk, And Aspen, Elaine M. Brice, Eric J. Larsen, Daniel R. Stahler, Daniel R. Macnulty

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The removal or addition of a predator in an ecosystem can trigger a trophic cascade, whereby the predator indirectly influences plants and/or abiotic processes via direct effects on its herbivore prey. A trophic cascade can operate through a density-mediated indirect effect (DMIE), where the predator reduces herbivore density via predation, and/or through a trait-mediated indirect effect (TMIE), where the predator induces an herbivore trait response that modifies the herbivore's effect on plants. Manipulative experiments suggest that TMIEs are an equivalent or more important driver of trophic cascades than are DMIEs. Whether this applies generally in nature is uncertain because few …

Animal Breeding-Rcn: Farm Animal Genomics Collective, Noelle E. Cockett

Funded Research Records

No abstract provided.

Nursery Cultural Practices Influence Morphological And Physiological Aspen Seedling Traits: Implications For Post-Fire Restoration, Aalap Dixit, Owen Burney

Aspen Bibliography

Aspen forests are threatened by the impacts of a changing climate and are showing large-scale mortality with meager natural regeneration to restore these loses. Therefore, there is an increasing demand for high-quality aspen seedlings to assist with forest restoration efforts. Nursery cultural practices can be used to alter aspen seedling traits to improve adaptability to dry planting conditions. In this study, the effects of container size (SC10 and D30; 158 and 590 mL, respectively) and nursery irrigation treatment (high and low irrigation; 90% and 70% container capacity, respectively) on seedling growth and a suite of morphological and physiological traits were …

Forest Defoliation By And Invasive Outbreak Insect: Catastrophic Consequences For A Charismatic Mega Moth, Richard L. Lindroth, Mark R. Zierden, Clay J. Morrow, Patricia C. Fernandez

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Earth is now experiencing declines in insect abundance and diversity unparalleled in human history. The drivers underlying those declines are many, complex, and incompletely known. Here, using a natural experiment, we report the first test of the hypothesis that forest defoliation by an invasive outbreak insect compromises the fitness of a native insect via damage-induced increases in toxicity of the forest canopy. We demonstrate that defoliation by the invasive spongy moth (Lymantria dispar) elicits an average 8.4-fold increase in foliar defense expression among aspen (Populus tremuloides) genotypes. In turn, elevated defense dramatically reduces survivorship, feeding, and …

Simulating The Long-Term Response Of Forest Succession To Climate Change In The Boreal Forest Of Northern Ontario, Canada, Guy R. Larocque, F. Wayne Bell, Eric B. Searle, Stephen J. Mayor, Thomas Schiks, Parvin Kalantari

Aspen Bibliography

The effect of climate change on forest dynamics is likely to increase in importance in the forthcoming decades. For this reason, it is essential to predict the extent to which changes in temperature, precipitation, and atmospheric CO₂ might affect the development of forest ecosystems and successional pathways. The gap model ZELIG-CFS was used to simulate the potential long-term effects of climate change on species-specific annual change in mean basal area and stand density under two scenarios of representative concentration pathways (RCP), 4.5 and 8.5, for the boreal forest region of Ontario, Canada, where mean temperature, precipitation, and atmospheric CO …

Modelling Climate Effects On Site Productivity And Developing Site Index Conversion Equations For Jack Pine And Trembling Aspen Mixed Stands, Mahadev Sharma

Aspen Bibliography

Forest site productivity estimates are crucial for making informed forest resource management decisions.These estimates are valuable both for the tree species currently growing in the stands and for those being considered for future stands. Current models are generally designed for pure stands and do not account for the influence of climate on tree growth. Consequently, site index (SI) conversion equations were developed specifically for jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) trees grown in naturally originated mixed stands. This work involved sampling 186 trees (93 of each species) from 31 even-aged mixed stands (3 …

Evaluation Of Major Physical And Mechanical Properties Of Trembling Aspen Lumber, Dawei Wang, Mengyuan Zhang, Meng Gong, Ying-Hei Chui

Aspen Bibliography

Trembling aspen (Populus tremuloides) is one of the major species within Populus, a predominant genus of hardwoods in North America. However, its utilization has been limited to pulp and paper or wood-based composite boards. This study aimed at evaluating the major physical and mechanical properties of trembling aspen lumber, with an ultimate objective of using this species to produce engineered wood products (EWPs). The testing materials consisted of 2 × 4 (38 mm × 89 mm) trembling aspen lumber pieces in lengths of 8, 10, and 12 feet (2.44, 3.05, and 3.66 m) with two visual grades, …

Mixing Trembling Aspen And White Spruce Increases The Understory Vegetation Cover And Improves Soil Properties But Effects Vary With Broadleaf Density, Mostarin Ara, Bradley D. Pinno, Philip G. Comeau

Aspen Bibliography

Despite the importance of species mixtures to ecosystem-based forest management, density effect of broadleaf trees in the mixture on understory vegetation and soil properties are poorly understood. In this study, we examine the effects of trembling aspen [aspen] (Populus tremuloides Michx.) -white spruce [ spruce] (Picea glauca (Moench) Vos) mixtures that vary in the proportion of aspen on understory vegetation cover, soil nutrient supply rates, and soil properties. Data were collected from an established study located in Alberta, Canada at age 20 and included the following treatments: 1. Natural regeneration of pure aspen; 2. Retaining only …

Aspen As Firebreaks At The Development Fringe, Kevin Krasnow, Paul C. Rogers

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Quaking aspen (Populus tremuloides) forests are widely known and prized for their numerous values—biodiversity, habitat, forage, recreation, aesthetics, and others—including as a deterrent to wildfire. This reputation for stopping or slowing flames is explored here, alongside measures that may be taken to facilitate thriving aspen communities near human developments. It is clear that science supporting the premise of aspen as an effective firebreak is far from complete. Yet, how can we benefit from what we do know on this topic to increase the probability of preventing structural fire damage, while also encouraging the valued characteristics of aspen ecosystems?

Climate Considerations For Quaking Aspen Conservation, Douglas Shinneman, Susan Mcilroy, Paul C. Rogers

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Human-caused climate change alters ecosystem processes ranging from local to global scales. As a consequence of climate change we should expect increased rates and intensities of disturbance events. Though we are only beginning to understand what those impacts might be to aspen forests and their diverse plant and animal assemblages, recent science suggests there may be unavoidable effects. In the face of anticipated climate-ecosystem challenges, contemporary managers are searching for guidance on preserving aspen resilience. We suggest crafting strategic yet cautious approaches to minimize effects and facilitate broad resilience. For instance, monitoring conditions in and near aspen forests will help …

Mapping Quaking Aspen Using Seasonal Sentinel-1 And Sentinel-2 Composite Imagery Across The Southern Rockies, Usa, Maxwell Cook, Teresa Chapman, Sarah Hart, Asha Paudel, Jennifer Balch

Aspen Bibliography

Quaking aspen is an important deciduous tree species across interior western U.S. forests. Existing maps of aspen distribution are based on Landsat imagery and often miss small stands ( < 0.09 ha or 30 m²), which rapidly regrow when managed or following disturbance. In this study, we present methods for deriving a new regional map of aspen forests using one year of Sentinel-1 (S1) and Sentinel-2 (S2) imagery in Google Earth Engine. Using observed annual phenology of aspen across the Southern Rockies and leveraging the frequent temporal resolution of S1 and S2, ecologically relevant seasonal imagery composites were developed. We derived spectral indices and …

Sustainability And Drivers Of Populus Tremuloides Regeneration And Recruitment Near The Southwestern Edge Of Its Range, Connor D. Crouch, Nicholas P. Wilhelmi, Paul C. Rogers, Margaret M. Moore, Kristen M. Waring

Aspen Bibliography

Quaking aspen (Populus tremuloides Michx.) ecosystems are highly valued in the southwestern United States because of the ecological, economic, and aesthetic benefits they provide. Aspen has experienced extensive mortality in recent decades, and there is evidence that many areas in Arizona, United States lack adequate recruitment to replace dying overstory trees. Maintaining sustainable levels of regeneration and recruitment (i.e. juveniles) is critical for promoting aspen ecosystem resilience and adaptive capacity, but questions remain about which factors currently limit juvenile aspen and which strategies are appropriate for managing aspen in an increasingly uncertain future. To fill these critical knowledge gaps, …

Where Have All The Flowers Gone? A Call For Federal Leadership In Deer Management In The United States, Bernd Blossey, Darragh Hare, Donald M. Waller

Aspen Bibliography

Forests in the United States continue to lose biodiversity and many fail to regenerate due to high deer (family Cervidae) abundance. Declines in biodiversity and overall ecosystem health due to high deer populations increases prevalence of wildlife and human diseases associated with increasing tick abundances and decreases forest resilience and the ability to deliver benefits provided by healthy ecosystems. In the eastern and midwestern United States, white-tailed deer (Odocoileus virginianus) are the main stressor, while in the western U.S. elk (Cervus elaphus) and black-tailed and mule deer (Odocoileus hemionus) can become equally problematic. Federal …

Eurasian Aspen (Populus Tremula L.): Central Europe's Keystone Species 'Hiding In Plain Sight', Antonín Kusbach, Jan Šebesta, Robert Hruban, Pavel Peška, Paul C. Rogers

Aspen Bibliography

Knowledge of Eurasian aspen’s (Populus tremula L.) ecological and growth characteristics is of high importance to plant and wildlife community ecology, and noncommercial forest ecosystem services. This research assessed these characteristics, identified aspen’s habitat optimum, and examined causality of its current scarce distribution in central Europe. We analyzed a robust database of field measurements (4,656,130 stands) for forest management planning over 78,000 km² of the Czech territory. Our analysis we used GIS techniques, with basic and multivariate statistics such as general linear models, ordination, and classification. Results describe a species of broad ecological amplitude that has heretofore attracted …

Envisioning Transition From Open Landscapes To Forested Landscapes In The Routt National Forest, Colorado, United States, Brice B. Hanberry, Jacob M. Seidel

Aspen Bibliography

Globally, in remaining wildlands, tree densities and forested cover have increased in grasslands and open forests since European settlement. In the southern Rocky Mountains of Colorado, United States, we determined tree composition and tree cover from historical (years 1875 to 1896) surveys and compared them to current (2002 to 2011) tree composition and current (year 2016) forested land cover for 500,000 ha of the Routt National Forest. Additionally, we examined whether changes in precipitation occurred. Regarding composition, pine (primarily lodgepole pine; Pinus contorta) decreased from 65% to 32% of all trees, with increased subalpine fir (Abies lasiocarpa) …

Can The Impact Of Gravel Roads On Organic Layer Thickness Explain The Distribution Of Populus Tremuloides Along Road Networks In The Boreal Forest Of Eastern Canada?, Mathilde Marchais, Dominique Arseneault, Yves Bergeron

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Roads are known to alter environmental conditions and the composition of road edge plant communities, particularly when exogenous materials are used as road surfacing. In this study, we evaluate the impact of gravel roads on the organic layer thickness (OLT) and aspen distribution in a boreal forest landscape of Eastern Canada. The OLT and aspen distribution were compared at different distances from the roads (0 m, 10 m, and >10 m) to determine whether a reduction in the OLT along the roads could explain the distribution of aspen along the road network, and in particular the role of the roads …

Oystershell Scale (Hemiptera: Diaspididae) Population Growth, Spread, And Phenology On Aspen In Arizona, Usa, Connor D. Crouch, Richard W. Hofstetter, Amanda M. Grady, Nylah N.S. Edwards, Kristen M. Waring

Aspen Bibliography

Oystershell scale (OSS; Lepidosaphes ulmi L.) is an invasive insect that threatens sustainability of aspen (Populus tremuloides Michx.) in the southwestern United States. OSS invasions have created challenges for land managers tasked with maintaining healthy aspen ecosystems for the ecological, economic, and aesthetic benefits they provide. Active management is required to suppress OSS populations and mitigate damage to aspen ecosystems, but before management strategies can be implemented, critical knowledge gaps about OSS biology and ecology must be filled. This study sought to fill these gaps by addressing 3 questions: (i) What is the short-term rate of aspen mortality in …

Pile Burning After Conifer Removal From Aspen Stands Affects Tree Mortality, Regeneration, And Understory Recovery, John-Pascal Berrill, Christa M. Dagley, Yoon G. Kim, J. Morgan Varner

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Quaking aspen (Populus tremuloides Michx.) stands throughout the western United States provide valuable ecosystem services but can be lost via succession from aspen to conifer. Forest managers are cutting conifers, but disposal of cut wood can be challenging in remote or sensitive areas. Piling and burning is being tested within aspen stands but ecosystem responses to this treatment are understudied. We assessed aspen tree mortality, tree regeneration, and understory vegetation after forest restoration thinning followed by pile burning in seven aspen-conifer stands around Lake Tahoe, California and Nevada, USA. Pile burning was conducted after cut wood had dried (1.5–7.5 …

Aspen Recovery In Northern Yellowstone: A Comment On Brice Et Al. (2021), Luke E. Painter, Robert L. Beschta, William J. Ripple

Aspen Bibliography

Aspen sapling recruitment increased as browsing by elk decreased, following the 1995–96 reintroduction of wolves in Yellowstone National Park. We address claims by Brice et al. (2021) that previous studies exaggerated recent aspen recovery. We conclude that their results actually supported previous work showing a trophic cascade benefiting aspen.

Aspen And Spruce Densities Affect Tree Size, Future Stand Volume, And Aboveground Carbon Following Precommercial Thinning, Philip G. Comeau, Mike Bokalo

Aspen Bibliography

Data collected over a 30-year period from an experiment replicated across 21 locations in western Canada are used to explore the effects of precommercial thinning of trembling aspen to a range of densities in combination with three initial white spruce densities on tree growth and stand dynamics. Increasing differentiation amongst the 15 treatments was observed with age after thinning for both spruce and aspen responses. Spruce height and diameter declined with increasing aspen density. At age 10 spruce diameter with no aspen was 1.5× that of spruce in unthinned while it was 2.6× that of spruce in unthinned at age …