Forest Sciences Commons^™

Coarse Woody Debris Decomposition Assessment Tool: Model Validation And Application, Zhaohua Dai, Carl C. Trettin, Andrew J. Burton, Martin F. Jurgensen, Deborah S. Page-Dumroese, Brian T. Forschler, Jonathan S. Schilling, Daniel L. Lindner

Aspen Bibliography

Coarse woody debris (CWD) is a significant component of the forest biomass pool; hence a model is warranted to predict CWD decomposition and its role in forest carbon (C) and nutrient cycling under varying management and climatic conditions. A process-based model, CWDDAT (Coarse Woody Debris Decomposition Assessment Tool) was calibrated and validated using data from the FACE (Free Air Carbon Dioxide Enrichment) Wood Decomposition Experiment utilizing pine (Pinus taeda), aspen (Populous tremuloides) and birch (Betula papyrifera) on nine Experimental Forests (EF) covering a range of climate, hydrology, and soil conditions across the continental USA. …

Tree Establishment On Post-Mining Waste Soils: Species, Density, And Mixture Effects, Degi Harja Asmara, Suzanne Allaire, Meine Van Noordwijk, Damase P. Khasa

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Tree establishment to restore degraded boreal post-mining lands is challenged by low soil productivity, a harsh microclimate, and potentially high contaminant levels. The use of mixed vegetation can facilitate the microclimate but increase competition for soil resources. A statistical accounting of plant–plant interactions and adaptation to multispecies conditions is hard to achieve in field experiments; trials under controlled conditions can distinguish effects of planting density and species interactions in the early stages of plant establishment. A greenhouse trial was established in containers (“mesocosms”) with waste rock or fine tailings from gold mines. Pregerminated (1-week-old) seedlings (Alnus viridis subsp. crispa …

Spatial And Temporal Variation Of Epigaeic Beetle Assemblages (Coleoptera, Carabidae, Staphylinidae) In Aspen-Dominated Mixedwood Forests Across North-Central Alberta, H. E. James Hammond, Sergio García-Tejero, Greg R. Pohl, David W. Langor, John R. Spence

Aspen Bibliography

Epigaeic beetle assemblages were surveyed using continuous pitfall trapping during the summers of 1992 and 1993 in six widely geographically distributed locations in Alberta’s aspen-mixedwood forests prior to initial forest harvest. Species composition and turnover (β-diversity) were evaluated on several spatial scales ranging from Natural Regions (distance between samples 120–420 km) to pitfall traps (40–60 m). A total of 19,885 ground beetles (Carabidae) representing 40 species and 12,669 rove beetles (non-Aleocharinae Staphylinidae) representing 78 species was collected. Beetle catch, species richness, and diversity differed significantly among the six locations, as did the identity of dominant species. Beetle species composition differed …

Splitting The Difference: Heterogeneous Soil Moisture Availability Affects Aboveground And Belowground Reserve And Mass Allocation In Trembling Aspen, Ashley T. Hart, Morgane Merlin, Erin Wiley, Simon M. Landhäusser

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When exploring the impact of resource availability on perennial plants, artificial treatments often apply conditions homogeneously across space and time, even though this rarely reflects conditions in natural systems. To investigate the effects of spatially heterogeneous soil moisture on morphological and physiological responses, trembling aspen (Populus tremuloides) saplings were used in a split-pot experiment. Following the division of the root systems, saplings were established for a full year and then subjected to either heterogeneous (portion of the root system exposed to non-lethal drought) or homogeneous (whole root system exposed to non-lethal drought or well-watered) treatments. Above- and belowground …

Chloroplast Genomes In Populus (Salicaceae): Comparisons From An Intensively Sampled Genus Reveal Dynamic Patterns Of Evolution, Jiawei Zhou, Shuo Zhang, Jie Wang, Hongmei Shen, Bin Ai, Wei Gao, Cuijun Zhang, Qili Fei, Daojun Yuan, Zhiqiang Wu, Luke R. Tembrock, Sen Li, Cuiha Gu, Xuezhu Liao

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The chloroplast is one of two organelles containing a separate genome that codes for essential and distinct cellular functions such as photosynthesis. Given the importance of chloroplasts in plant metabolism, the genomic architecture and gene content have been strongly conserved through long periods of time and as such are useful molecular tools for evolutionary inferences. At present, complete chloroplast genomes from over 4000 species have been deposited into publicly accessible databases. Despite the large number of complete chloroplast genomes, comprehensive analyses regarding genome architecture and gene content have not been conducted for many lineages with complete species sampling. In this …

Pando's Lessons: Restoration Of A Giant Aspen Clone, Paul C. Rogers, Jody Gale, Darren Mcavoy

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A 106 acre (43 ha) aspen clone lives in the Fishlake National Forest in south-central Utah. Clones are comprised of multiple aspen stems, called ramets, which are genetically identical. This particular colony of ramets was named “Pando” (Latin for “I spread”) by researchers believing it to be the largest living organism by mass on earth. Recently, forest managers have noted a rapid dying of mature stems without recruitment of younger trees. This unsustainable situation has galvanized restoration efforts at Pando. Human interventions caused this imbalance; restoration will rely on protection, monitoring, and innovation. As a laboratory, this forest icon may …

Detection Of European Aspen (Populus Tremula L.) Based On An Unmanned Aerial Vehicle Approach In Boreal Forests, Anton Kuzmin, Lauri Korhonen, Sonja Kivinen, Pekka Hurskainen, Pasi Korpelainen, Topi Tanhuanpää, Matti Maltamo, Petteri Vihervaara, Timo Kumpula

Aspen Bibliography

European aspen (Populus tremula L.) is a keystone species for biodiversity of boreal forests. Large-diameter aspens maintain the diversity of hundreds of species, many of which are threatened in Fennoscandia. Due to a low economic value and relatively sparse and scattered occurrence of aspen in boreal forests, there is a lack of information of the spatial and temporal distribution of aspen, which hampers efficient planning and implementation of sustainable forest management practices and conservation efforts. Our objective was to assess identification of European aspen at the individual tree level in a southern boreal forest using high-resolution photogrammetric point cloud …

Prescribed Fire Alters Structure And Composition Of A Mid-Atlantic Oak Forest Up To Eight Years After Burning, Cody L. Dems, Alan H. Taylor, Erica A. H. Smithwick, Jesse K. Kreye, Margot W. Kaye

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Background

Prescribed fire in Eastern deciduous forests has been understudied relative to other regions in the United States. In Pennsylvania, USA, prescribed fire use has increased more than five-fold since 2009, yet forest response has not been extensively studied. Due to variations in forest composition and the feedback between vegetation and fire, Pennsylvania deciduous forests may burn and respond differently than forests across the eastern US. We measured changes in forest structure and composition up to eight years after prescribed fire in a hardwood forest of the Ridge and Valley region of the Appalachian Mountains in central Pennsylvania.

Results

Within …

Widespread Mortality Of Trembling Aspen (Populus Tremuloides) Throughout Interior Alaskan Boreal Forests Resulting From A Novel Canker Disease, Roger W. Ruess, Loretta M. Winton, Gerard C. Adams

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Over the past several decades, growth declines and mortality of trembling aspen throughout western Canada and the United States have been linked to drought, often interacting with outbreaks of insects and fungal pathogens, resulting in a “sudden aspen decline” throughout much of aspen’s range. In 2015, we noticed an aggressive fungal canker causing widespread mortality of aspen throughout interior Alaska and initiated a study to quantify potential drivers for the incidence, virulence, and distribution of the disease. Stand-level infection rates among 88 study sites distributed across 6 Alaska ecoregions ranged from < 1 to 69%, with the proportion of trees with canker that were dead averaging 70% across all sites. The disease is most prevalent north of the Alaska Range within the Tanana Kuskokwim ecoregion. Modeling canker probability as a function of ecoregion, stand structure, landscape position, and climate revealed that smaller-diameter trees in older stands with greater aspen basal area have the highest canker incidence and mortality, while younger trees in younger stands appear virtually immune to the disease. Sites with higher summer vapor pressure deficits had significantly higher levels of canker infection and mortality. We believe the combined effects of this novel fungal canker pathogen, drought, and the persistent aspen leaf miner outbreak are triggering feedbacks between carbon starvation and hydraulic failure that are ultimately driving widespread mortality. Warmer early-season temperatures and prolonged late summer drought are leading to larger and more severe wildfires throughout interior Alaska that are favoring a shift from black spruce to forests dominated by Alaska paper birch and aspen. Widespread aspen mortality fostered by this rapidly spreading pathogen has significant implications for successional dynamics, ecosystem function, and feedbacks to disturbance regimes, particularly on sites too dry for Alaska paper birch.

Historic Declines In Growth Portend Trembling Aspen Death During A Contemporary Leaf Miner Outbreak In Alaska, Melissa A. Boyd, Logan T. Berner, Adrianna C. Foster, Scott J. Goetz, Brendan M. Rogers, Xanthe J. Walker, Michelle C. Mack

Aspen Bibliography

Climate change-driven droughts and insect outbreaks are becoming more frequent and widespread, increasing forest vulnerability to mortality. By addressing the impacts of climate and insects on tree growth preceding death, we can better understand tree mortality risk under a changing climate. Here, we used tree stature and interannual growth (basal area increment; BAI) to assess processes leading to trembling aspen (Populus tremuloides) survival or mortality during an unprecedented leaf miner (Phyllocnistis populiella) outbreak in boreal North America. We identified eight sites (22 plots) in the longest running forest monitoring network in Alaska, spanning ~350 km of …

Pando: Charismatic Megaflora And The Populus Paradox, Paul C. Rogers, Lance Oditt

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Within the field of landscape ecology, the Pando aspen grove on the Fishlake National Forest of Utah is legendary—and it is in danger of dying from hotter, drier temperatures and other threats. Pando is one of the largest and oldest known still-living organisms on Earth. Quaking aspen are an important tree species in Greater Yellowstone and the Rocky Mountain West. Enjoy this essay written by a scientist who studies Pando and a photographer who celebrates this arboreal mega-being.

The Annual Rhythmic Differentiation Of Populus Davidiana Growth–Climate Response Under A Warming Climate In The Greater Hinggan Mountains, Ruixin Yun, Yuting Jin, Junxia Li, Zhenju Chen, Zhaoyang Lyu, Ying Zhao, Di Cui

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The stability and balance of forest ecosystems have been seriously affected by climate change. Herein, we use dendrochronological methods to investigate the radial growth and climate response of pioneer tree species in the southern margin of cold temperate coniferous forest based on Populus davidiana growing on the Greater Hinggan Mountains in northeastern China. Correlations of P. davidiana growth with temperature and precipitation in a year (October–September) were rhythmically opposed: while temperatures in previous October–June (winter and spring) and in May–September (growing season) respectively inhibited and promoted radial growth on P. davidiana (p < 0.01), precipitation in the same periods respectively promoted and inhibited of growth (p < 0.01). High temperature or less rain/snow in winter and early spring, and low temperature or excess rainfall in summer, are inconducive to P. davidiana growth and vice versa …

Improved Boreal Forest Wildfire Fuel Type Mapping In Interior Alaska Using Aviris-Ng Hyperspectral Data, Christopher William Smith, Santosh K. Panda, Uma Suren Bhatt, Franz J. Meyer

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In Alaska the current wildfire fuel map products were generated from low spatial (30 m) and spectral resolution (11 bands) Landsat 8 satellite imagery which resulted in map products that not only lack the granularity but also have insufficient accuracy to be effective in fire and fuel management at a local scale. In this study we used higher spatial and spectral resolution AVIRIS-NG hyperspectral data (acquired as part of the NASA ABoVE project campaign) to generate boreal forest vegetation and fire fuel maps. Based on our field plot data, random forest classified images derived from 304 AVIRIS-NG bands at Viereck …

European Aspen With High Compared To Low Constitutive Tannin Defenses Grow Taller In Response To Anthropogenic Nitrogen Enrichment, Franziska Bandau, Benedicte Riber Albrectsen, Kathryn M. Robinson, Michael J. Gundale

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Boreal forests receive nitrogen-(N)-enrichment via atmospheric deposition and industrial fertilization. While it is known that N-enrichment can intensify interactions with natural antagonists, it remains poorly understood how genetic variability in plant defense chemistry can affect biotic interactions and height growth in N-enriched environments. We grew replicates of five low- and high-tannin Populus tremula genotypes, respectively, under three N-treatments (ambient, 15, and 150 kg N ha−1 yr−1). We assessed shoot blight occurrence (i.e. symptoms caused by Venturia fungi) during four growing seasons, and tree height growth during the same period. Damage by Venturia spp. increased with N-addition during all years, likely …

76-Year Decline And Recovery Of Aspen Mediated By Contrasting Fire Regimes: Long-Unburned, Infrequent And Frequent Mixed-Severity Wildfire, Cerena J. Brewen, John-Pascal Berrill, Martin W. Ritchie, Kevin Boston, Christa M. Dagley, Bobette Jones, Michelle Coppoletta, Coye L. Burnett

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Quaking aspen (Populus tremuloides) is a valued, minor component on northeastern California landscapes. It provides a wide range of ecosystem services and has been in decline throughout the region for the last century. This decline may be explained partially by the lack of fire on the landscape due to heavier fire suppression, as aspen benefit from fire that eliminates conifer competition and stimulates reproduction through root suckering. However, there is little known about how aspen stand area changes in response to overlapping fire. Our study area in northeastern California on the Lassen, Modoc and Plumas National Forests has …

Fire Alters Plant Microbiome Assembly Patterns: Integrating The Plant And Soil Microbial Response To Disturbance, Nicholas C. Dove, Dawn M. Klingeman, Alyssa A. Carrell, Melissa A. Cregger, Christopher W. Schadt

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• It is increasingly evident that the plant microbiome is a strong determinant of plant health. While the ability to manipulate the microbiome in plants and ecosystems recovering from disturbance may be useful, our understanding of the plant microbiome in regenerating plant communities is currently limited.
• Using 16S ribosomal RNA (rRNA) gene and internal transcribed spacer (ITS) region amplicon sequencing, we characterized the leaf, stem, fine root, rhizome, and rhizosphere microbiome of < 1-yr-old aspen saplings and the associated bulk soil after a recent high-intensity prescribed fire across a burn severity gradient.
• Consistent with previous studies, we found that soil microbiomes are responsive to fire. We extend these findings by showing that certain plant tissue microbiomes also change in response to …

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

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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 …

Effects Of Thinning On Dynamics And Drought Resistance Of Aspen-White Spruce Mixtures: Results From Two Study Sites In Saskatchewan, Philip G. Comeau

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Drought stress associated with warm temperatures is causing increased mortality and reduced growth of trees in drier portions of the boreal forests of western Canada with both warming and drought expected to increase over the coming decades. While thinning is often shown to reduce drought stress, there is little information on its effects in stands comprised of mixtures of trembling aspen and white spruce that are common in the forests of this region. This study examined effects of pre-commercial thinning on aspen and spruce growth, response to drought stress, and stand dynamics for two study sites located in Saskatchewan, Canada. …

White River Aspen Management Project, Usda Forest Service

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Comments Welcome

The White River National Forest (WRNF) welcomes your comments on its proposal to conduct vegetation management activities designed to sustain and expand aspen (Populus tremuloides) forests on National Forest System (NFS) lands. Your comments will help us further develop the proposed action, potential alternatives, and complete an environmental assessment. The assessment will be used to determine whether to prepare an environmental impact statement or a finding of no significant impact. Instructions for submitting comments are described on the last page. Additional project information is available here: https://www.fs.usda.gov/project/?project=59419

This Notice of Proposed Action (NOPA) is also requesting …

Fungal Planet Description Sheets: 1112–1181, P. W. Crous, D. A. Cowan, G. Maggs-Kölling, N. Yilmaz, E. Larsson, C. Angelini, T. E. Brandrud, J. D. W. Dearnaley, B. Dima, F. Dovana, Et Al.

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Novel species of fungi described in this study include those from various countries as follows: Australia, Austroboletus asper on soil, Cylindromonium alloxyli on leaves of Alloxylon pinnatum, Davidhawksworthia quintiniae on leaves of Quintinia sieberi, Exophiala prostantherae on leaves of Prostanthera sp., Lactifluus lactiglaucus on soil, Linteromyces quintiniae (incl. Linteromyces gen. nov.) on leaves of Quintinia sieberi, Lophotrichus medusoides from stem tissue of Citrus garrawayi, Mycena pulchra on soil, Neocalonectria tristaniopsidis (incl. Neocalonectria gen. nov.) and Xyladictyochaeta tristaniopsidis on leaves of Tristaniopsis collina, Parasarocladium tasmanniae on leaves of Tasmannia insipida, Phytophthora aquae-cooljarloo from pond water, Serendipita whamiae as …

Aspen Soils Retain More Dissolved Organic Carbon Than Conifer Soils In A Sorption Experiment, Antra Boča, Astrid R. Jacobson, Helga Van Miegroet

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The effect tree species have on soil organic carbon (SOC) has been hotly debated but, so far, few clear patterns have emerged. One example of a differing tree species effect on SOC are aspen forests in North America, which have been found to have more stable SOC than adjacent conifer forest stands. An important source for the formation of stable organo-mineral complexes in soil is dissolved organic carbon (DOC). DOC concentrations in mineral soil are often higher under the thick O-horizons of conifer forests than under aspen forests, but this does not correspond to more stable mineral SOC. This suggests …

Simulated Fire Behavior And Fine-Scale Forest Structure Following Conifer Removal In Aspen-Conifer Forests In The Lake Tahoe Basin, Usa, Justin P. Ziegler, Chad M. Hoffman, Brandon M. Collins, Jonathan W. Long, Christa M. Dagley, William Mell

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Quaking aspen is found in western forests of the United States and is currently at risk of loss due to conifer competition at within-stand scales. Wildfires in these forests are impactful owing to conifer infilling during prolonged fire suppression post-Euro-American settlement. Here, restoration cuttings seek to impact wildfire behavior and aspen growing conditions. In this study, we explored how actual and hypothetical cuttings with a range of conifer removal intensity altered surface fuel and overstory structure at stand and fine scales. We then simulated wildfires, examining fire behavior and effects on post-fire forest structures around aspen trees. We found that …

Drought- Conditioning Of Quaking Aspen (Populus Tremuloides Michx.) Seedlings During Nursery Production Modifies Seedling Anatomy And Physiology, Joshua L. Sloan, Owen T. Burney, Jeremiah R. Pinto

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In the western US, quaking aspen (Populus tremuloides Michx.) regenerates primarily by root suckers after disturbances such as low to moderate severity fires. Planting aspen seedlings grown from seed may provide a mechanism to improve restoration success and genetic diversity on severely disturbed sites. However, few studies have examined the use of container-grown aspen seedlings for restoration purposes from both the outplanting and nursery production perspective. Thus, the purpose of this novel study was to examine how alterations in irrigation levels during nursery production across three seed sources would impact seedling performance attributes on harsh, dry outplanting sites. Irrigation …

Patterns For Populus Spp. Stand Biomass In Gradients Of Winter Temperature And Precipitation Of Eurasia, Vladimir Andreevich Usoltev, Baozhang Chen, Seyed Omid Reza Shobairi, Ivan Stepanovich Tsepordey, Viktor Petrovich Chasovskikh, Shoaib Ahmad Anees

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Based on a generated database of 413 sample plots, with definitions of stand biomass of the genus Populus spp. in Eurasia, from France to Japan and southern China, statistically significant changes in the structure of forest stand biomass were found, with shifts in winter temperatures and average annual precipitation. When analyzing the reaction of the structure of the biomass of the genus Populus to temperature and precipitation in their transcontinental gradients, a clearly expressed positive relationship of all components of the biomass with the temperature in January is visible. Their relationship with precipitation is less clear; in warm climate zones, …

Genomic Insights Into Speciation History And Local Adaptation Of An Alpine Aspen In The Qinghai–Tibet Plateau And Adjacent Highlands, Jia-Lang Li, Lin-Ling Zhong, Jing Wang, Tao Ma, Kang-Shan Mao, Lei Zhang

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Natural selection serves as an important agent to drive and maintain interspecific divergence. Populus rotundifolia Griff. is an alpine aspen species that mainly occurs in the Qinghai–Tibet Plateau (QTP) and adjacent highlands, whereas its sister species, P. davidiana Dode, is distributed across southwest and central to northeast China in much lower altitude regions. In this study, we collected genome resequencing data of 53 P. rotundifolia and 42 P. davidiana individuals across their natural distribution regions. Our population genomic data suggest that the two species are well delimitated in the allopatric regions, but with hybrid zones in their adjacent region in …

Aspen Next Generation: Conversations From Southern Colorado And Northern New Mexico, Dan Binkley, Bill Romme

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Aspen trees and forests are especially important in the Rocky Mountains. Aspens add beauty to landscapes, foster high diversity and productivity of understory plants, provide for the habitat needs of many species of animals, and moderate fire behavior. There is a perception that aspen trees and stands are not regenerating well in southern Colorado and northern New Mexico; cohorts of trees younger than a few decades are scarce, at least in some areas. The next generation of aspen in the southern Rockies will be influenced by land use decisions, including harvesting, fire policy and management, and browsing by livestock and …

Long-Term Soil Productivity Study: 25-Year Vegetation Response To Varying Degrees Of Disturbance In Aspen-Dominated Forest Spanning The Upper Lake States, Miranda T. Curzon, Brian J. Palik, Anthony W. D'Amato, Julia Schwager

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Installations of the Long-Term Soil Productivity Study were established in northern Minnesota and Michigan at the Chippewa, Ottawa, and Huron-Manistee National Forests (NFs) in the early 1990s and have since provided a wealth of data for assessing the response of aspen-dominated forest ecosystems to varying levels of organic matter removal and soil compaction. An assessment of 25-year standing woody biomass indicates that neither whole-tree harvest nor whole-tree harvest combined with forest floor removal reduced forest productivity on silt-loam soils compared with conventional, stem-only harvest; however, moderate and heavy compaction did negatively impact aspen biomass and stem densities. In contrast, whole-tree …

Genetic Parameters Of Growth And Adaptive Traits In Aspen (Populus Tremuloides): Implications For Tree Breeding In A Warming World, Chen Ding, Andreas Hamann, Rong-Cai Yang, Jean S. Brouard

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Aspen (Populus tremuloides Michx) is a widespread commercial forest tree of high economic importance in western Canada and has been subject to tree improvement efforts over the past two decades. Such improvement programs rely on accurate estimates of the genetic gain in growth traits and correlated response in adaptive traits that are important for forest health. Here, we estimated genetic parameters in 10 progeny trials containing >30,000 trees with pedigree structures based on a partial factorial mating design that includes 60 half-sibs, 100 full-sib families and 1,400 clonally replicated genotypes. Estimated narrow-sense and broad-sense heritabilities were low for height …

Contrasting Root System Structure And Belowground Interactions Between Black Spruce (Picea Mariana (Mill.) B.S.P) And Trembling Aspen (Populus Tremuloides Michx) In Boreal Mixedwoods Of Eastern Canada, Claudele Ghotsa Mekontchou, Daniel Houle, Yves Bergeron, Igor Drobyshev

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This study explored the underground interactions between black spruce and trembling aspen in pure and mixed stands to understand how their soil resource use help these species coexist in the boreal mixedwoods of Western Quebec. We analyzed species-specific fine root foraging strategies (root biomass and root tissue density) along three soil layers (organic, top 0–15 cm, and bottom 15–30 cm mineral soil), using 180 soil cores. We collected cores in three sites, each containing three 20 × 50 m2 plots of pure spruce, pure aspen, and mixed spruce and aspen stands. Spruce had a shallow rooting, whereas aspen had a …

Patterns Of Epiphytic Lichen Abundance On Aspen Stands In Proximity To Roads Of Varying Vehicular Traffic, D. Aragon, C. Castillo, J. Moffroid, G. Thomas

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Although present in nearly any wild space with available moisture and on a wide variety of substrates, lichen, and its importance as a bioindicator for an ecosystem, is often overlooked. As air pollution becomes a greater concern for flora, fauna, and even humans, the story told by lichen growth becomes more useful as we try to make sense of the downstream effects of anthropogenic contributions to poor air quality. One such human-driven pollutant is the level of emissions that result from vehicular travel. The Jackson Hole area has experienced a large increase in vehicular traffic in the past five to …