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Sample records for eastern spruce structural

  1. Eastern Spruce Dwarf Mistletoe

    Treesearch

    F. Baker; Joseph O' Brien; R. Mathiasen; Mike Ostry

    2006-01-01

    Eastern spruce dwarf mistletoe (Arceuthobium pusillum) is a parasitic flowering plant that causes the most serious disease of black spruce (Picea mariana) throughout its range. The parasite occurs in the Canadian provinces of Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland; in the Lake States of Minnesota,...

  2. Stand structure, recruitment and growth dynamics in mixed subalpine spruce and Swiss stone pine forests in the Eastern Carpathians.

    PubMed

    Popa, Ionel; Nechita, Constantin; Hofgaard, Annika

    2017-11-15

    Natural subalpine forests are considered to be sensitive to climate change, and forest characteristics are assumed to reflect the prevalent disturbance regime. We hypothesize that stand history determines different stand structures. Based on large full inventory datasets (including tree biometric data, spatial coordinates, tree age, and basal area increment) we assessed the size structure, tree recruitment dynamics and radial growth patterns in three permanent plots along an altitudinal gradient in a mixed coniferous forest (Picea abies and Pinus cembra) in the Eastern Carpathians. Both discrete disturbances (large scale or small scale) and chronic disturbances (climate change) were identified as drivers of stand structure development in the studied plots. A stand replacing wind disturbance generated a unimodal bell-shaped size and age distribution for both species characterized by a sharp increase in post-disturbance recruitment. By contrast, small-scale wind-caused gaps led to a negative exponential diameter distribution for spruce and a left-asymmetric unimodal for pine. Climate-driven infilling processes in the upper subalpine forest were reflected as J-shaped size and age distributions for both species, but with pine predating spruce. The growth patterns for both species demonstrated an increased basal area increment since the early 1900s, with an emphasis in the last few decades, irrespective of stand history. Pine demonstrated a competitive advantage compared to spruce due to the higher growth rate and size at the same age. Recognition of combined discrete and chronic disturbances as drivers of the tree layer characteristics in a subalpine coniferous forest is essential in both stand history analyses and growth predictions. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Characterization of eastern US spruce-fir soils. Book chapter

    SciTech Connect

    Fernandez, I.J.

    1992-01-01

    The spruce-fir forest of the eastern United States encompasses a diverse range of edaphic conditions due to differences in surficial geology, mineralogy, elevation, and climate. This chapter describes the characteristics of soils supporting eastern spruce-fir ecosystems, including soil properties that are important in understanding forest function and the consequences of atmospheric deposition to forested ecosystems. Chapter 1 describes the silvical characteristics of the spruce-fir forest. The Spruce-Fir Research Cooperative included six intensive study sites; five were high-elevation research sites located from western North Carolina to New Hampshire, with one low-elevation site in Maine. Information gained from research at these sites, and other relevant research from these regions, provides the basis for this description of eastern U. S. spruce-fir soils.

  4. Animal vectors of eastern dwarf mistletoe of black spruce.

    Treesearch

    Michael E. Ostry; Thomas H. Nicholls; D.W. French

    1983-01-01

    Describes a study to determine the importance of animals in the spread of eastern dwarf mistletoe of black spruce. Radio telemetry, banding, and color-marking techniques were used to study vectors of this forest pathogen.

  5. Effects of a western spruce budworm outbreak on private lands in eastern Oregon, 1980-1994.

    Treesearch

    David L. Azuma; David L. Overhulser

    2008-01-01

    Forest Inventory and Analysis data from three inventory periods were used to examine the effects of a western spruce budworm outbreak on private lands in eastern Oregon. Growth was negatively related to defoliation with differences between crown ratio and species. The mortality and salvage harvesting caused changes in stand structure on private lands. Although many...

  6. AmeriFlux CA-Qfo Quebec - Eastern Boreal, Mature Black Spruce

    DOE Data Explorer

    Margolis, Hank A. [Université Laval

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site CA-Qfo Quebec - Eastern Boreal, Mature Black Spruce. Site Description - 49.69247° N / 74.34204° W, elevation of 387 mm, 90 - 100 yr old Black Spruce, Jack Pine, feather moss

  7. The structure of genetic diversity in Engelmann spruce and a comparison with blue spruce

    Treesearch

    F. Thomas Ledig; Paul D. Hodgskiss; David R. Johnson

    2010-01-01

    Genetic diversity and genetic structure in Engelmann spruce (Picea engelmannii Parry ex Engelm.) were interpreted with respect to the effects of glacial and interglacial displacement and compared with patterns in blue spruce (Picea pungens Engelm.), which occupies a range well south of the last glacial front. On average,...

  8. Impact of eastern dwarf mistletoe (Arceuthobium pusillum) infection on the needles of red spruce (Picea rubens) and white spruce (Picea glauca): oxygen exchange, morphology and composition.

    PubMed

    Reblin, Jaret S; Logan, Barry A; Tissue, David T

    2006-10-01

    Eastern dwarf mistletoe (Arceuthobium pusillum Peck) is a hemiparasitic angiosperm that infects white spruce (Picea glauca (Moench) Voss) and red spruce (P. rubens Sarg.) in northeastern North America. The effects of mistletoe infection differ substantially between white and red spruce, with white spruce suffering greater infection-induced mortality. In the present study, we sought to determine the role that species-specific differences in needle-scale responses to parasitism may play in the observed differences in the effect of infection on host tree health. Based on the measurements made, the most apparent effect of parasitism was a reduction in needle size distal to infections. The magnitude of this reduction was greater in white spruce than in red spruce. Eastern dwarf mistletoe was a sink for host photosynthate in red spruce and white spruce; however, there were no adjustments in needle photosynthetic capacities in either host to accommodate the added sink demands of the parasite. Needle total nonstructural carbohydrate concentrations (TNC) were also unaltered by infection. Red spruce needles had higher TNC concentrations despite having lower overall photosynthetic capacities, suggesting that red spruce may be more sink limited and therefore better able to satisfy the added sink demands of parasitic infection. However, if carbon availability limits the growth of the mistletoe, one may expect that the extent of the parasitic infection would be greater in red spruce. Yet in the field, the extent of infection is generally greater in white spruce. Taken together, these results suggest that dwarf mistletoe may not substantially perturb the carbon balance of either host spruce species and that species-specific differences in needle-scale responses to the parasite cannot explain the contrasting effects of infection on white spruce and red spruce.

  9. Western spruce budworm defoliation effects on forest structure and potential fire behavior.

    Treesearch

    S. Hummel; J.K. Agee

    2003-01-01

    Forest composition and structure on the eastern slope of the Cascade Mountains have been influenced by decades of fire exclusion. Multilayered canopies and high numbers of shade-tolerant true fir trees interact with western spruce budworm to alter forest structure and to affect potential fire behavior and effects. We compared...

  10. Incidental captures of Eastern Spotted Skunk in a high-elevation Red Spruce forest in Virginia

    USGS Publications Warehouse

    Diggins, Corinne A.; Jachowski, David S.; Martin, Jay; Ford, W. Mark

    2015-01-01

    Spilogale putorius (Eastern Spotted Skunk) is considered rare in the southern Appalachian Mountains and throughout much of its range. We report incidental captures of 6 Eastern Spotted Skunks in a high-elevation Picea rubens (Red Spruce) forest in southwestern Virginia during late February and March 2014. At 1520 m, these observations are the highest-elevation records for Eastern Spotted Skunk in the Appalachian Mountains. They are also the first known records of this species using Red Spruce forests in the southern Appalachians.

  11. Availability of Ectomycorrhizal Fungi to Black Spruce above the Present Treeline in Eastern Labrador

    PubMed Central

    Reithmeier, Laura; Kernaghan, Gavin

    2013-01-01

    Ectomycorrhizal fungi (ECMF) are an important biotic factor in the survival of conifer seedlings under stressful conditions and therefore have the potential to facilitate conifer establishment into alpine and tundra habitats. In order to assess patterns of ectomycorrhizal availability and community structure above treeline, we conducted soil bioassays in which Picea mariana (black spruce) seedlings were grown in field-collected soils under controlled conditions. Soils were collected from distinct alpine habitats, each dominated by a different ectomycorrhizal host shrub: Betula glandulosa, Arctostaphylos alpina or Salix herbacaea. Within each habitat, half of the soils collected contained roots of ectomycorrhizal shrubs (host+) and the other half were free of host plants (host−). Forest and glacial moraine soils were also included for comparison. Fungi forming ectomycorrhizae during the bioassays were identified by DNA sequencing. Our results indicate that ECMF capable of colonizing black spruce are widespread above the current tree line in Eastern Labrador and that the level of available inoculum has a significant influence on the growth of seedlings under controlled conditions. Many of the host− soils possessed appreciable levels of ectomycorrhizal inoculum, likely in the form of spore banks. Inoculum levels in these soils may be influenced by spore production from neighboring soils where ectomycorrhizal shrubs are present. Under predicted temperature increases, ectomycorrhizal inoculum in soils with host shrubs as well as in nearby soils without host shrubs have the potential to facilitate conifer establishment above the present tree line. PMID:24204858

  12. A western larch-engelmann spruce spacing study in eastern Oregon: results after 10 years.

    Treesearch

    K.W. Seidel

    1984-01-01

    The 10-year growth response from a spacing study in an even-aged stand of western larch (Larix occidentalis Nutt.) and Engelmann spruce (Picea engelmannii Parry ex Engelm.), thinned at age 10 to 9- and 15-foot spacings, was measured in eastern Oregon. Both basal area and total cubic volume increment per acre increased at the...

  13. Relationships between forest structure, composition, site, and spruce beetle occurrence in the Intermountain West

    Treesearch

    R. Justin DeRose; James N. Long; John D. Shaw

    2009-01-01

    Engelmann spruce forests are structurally and compositionally diverse, occur across a wide range of physiographic conditions, and are the result of varying disturbance histories such as fire, wind and spruce beetle. The spruce beetle is a natural disturbance agent of spruce forests and has population levels that fluctuate from endemic to epidemic. Conceptually,...

  14. Pattern analysis of eastern spruce budworm Choristoneura fumiferana dispersal

    Treesearch

    Dean P. Anderson; Brian R. Sturtevant

    2011-01-01

    Dispersal has been proposed as an important mechanism in the broad-scale synchronisation of insect outbreaks by linking spatially disjunct populations. Evidence suggests that dispersal is influenced by landscape structure, phenology, temperature, and air currents; however, the details remain unclear due to the difficulty of quantifying dispersal. In this study, we used...

  15. Paradigms in Eastern Spruce Budworm (Lepidoptera: Tortricidae) Population Ecology: A Century of Debate.

    PubMed

    Pureswaran, Deepa S; Johns, Rob; Heard, Stephen B; Quiring, Dan

    2016-09-01

    Three main hypotheses have been postulated over the past century to explain the outbreaking population dynamics of eastern spruce budworm, Choristoneura fumiferana (Clemens). The Silviculture Hypothesis first arose in the 1920s, with the idea that outbreaks were driven by forestry practices favoring susceptible softwood species. In the 1960s, it was proposed that populations were governed by Multiple Equilibria, with warm weather conditions releasing low-density populations from the regulatory control of natural enemies. Dispersal from outbreak foci, or "epicenters," was seen as causing widespread outbreaks that eventually collapsed following resource depletion. However, in the 1980s, following the re-analysis of data from the 1940s outbreak in New Brunswick, this interpretation was challenged. The alternative Oscillatory Hypothesis proposed that budworm population dynamics were governed by a second-order density-dependent process, with oscillations being driven by natural enemy-victim interactions. Under this hypothesis, weather and resource availability contribute to secondary fluctuations around the main oscillation, and weather and moth dispersal serve to synchronize population cycles regionally. Intensive, independent population studies during the peak and declining phases of the 1980s outbreak supported the principal tenet of the Oscillatory Hypothesis, but concluded that host plant quality played a more important role than this hypothesis proposed. More recent research on the early phase of spruce budworm cycles suggests that mate-finding and natural-enemy-driven Allee effects in low-density populations might be overcome by immigration of moths, which can facilitate the onset of outbreaks. Even more recent research has supported components of all three hypotheses attempting to explain spruce budworm dynamics. In the midst of a new rising outbreak (2006-present), we discuss the evolution of debates surrounding these hypotheses from a historic perspective

  16. Paradigms in Eastern Spruce Budworm (Lepidoptera: Tortricidae) Population Ecology: A Century of Debate.

    PubMed

    Pureswaran, Deepa S; Johns, Rob; Heard, Stephen B; Quiring, Dan

    2016-12-01

    Three main hypotheses have been postulated over the past century to explain the outbreaking population dynamics of eastern spruce budworm, Choristoneura fumiferana (Clemens). The Silviculture Hypothesis first arose in the 1920s, with the idea that outbreaks were driven by forestry practices favoring susceptible softwood species. In the 1960s, it was proposed that populations were governed by Multiple Equilibria, with warm weather conditions releasing low-density populations from the regulatory control of natural enemies. Dispersal from outbreak foci, or "epicenters," was seen as causing widespread outbreaks that eventually collapsed following resource depletion. However, in the 1980s, following the re-analysis of data from the 1940s outbreak in New Brunswick, this interpretation was challenged. The alternative Oscillatory Hypothesis proposed that budworm population dynamics were governed by a second-order density-dependent process, with oscillations being driven by natural enemy-victim interactions. Under this hypothesis, weather and resource availability contribute to secondary fluctuations around the main oscillation, and weather and moth dispersal serve to synchronize population cycles regionally. Intensive, independent population studies during the peak and declining phases of the 1980s outbreak supported the principal tenet of the Oscillatory Hypothesis, but concluded that host plant quality played a more important role than this hypothesis proposed. More recent research on the early phase of spruce budworm cycles suggests that mate-finding and natural-enemy-driven Allee effects in low-density populations might be overcome by immigration of moths, which can facilitate the onset of outbreaks. Even more recent research has supported components of all three hypotheses attempting to explain spruce budworm dynamics. In the midst of a new rising outbreak (2006-present), we discuss the evolution of debates surrounding these hypotheses from a historic perspective

  17. AmeriFlux CA-Qcu Quebec - Eastern Boreal, Black Spruce/Jack Pine Cutover

    DOE Data Explorer

    Margolis, Hank A. [Université Laval

    2016-01-01

    This is the AmeriFlux version of the carbon flux data for the site CA-Qcu Quebec - Eastern Boreal, Black Spruce/Jack Pine Cutover. Site Description - The ground is gently rolling with a weak slope (<5%). In mesic areas (designated as well to moderately well drained areas, according to the Canadian System of Soil Classification (Agriculture Canada Expert Committee on Soil Survey, 1983)), the soil is a ferro-humic to humic podzol covered by an organic layer having an average depth of 26 cm (Fig. 1). In humid areas, the soil is organic (imperfectly to poorly drained) with an average organic layer of 125 cm. Mesic areas accounted for approximately 75% of the total surface area of the footprint and humid areas accounted for 25%. Full-time continuous measurements eneded in 2011. Intermittent measurements are on-going as resources permit.

  18. Sources of polycyclic aromatic hydrocarbons and hexachlorobenzene in spruce needles of eastern Alaska.

    PubMed

    Howe, Timothy S; Billings, Shane; Stolzberg, Richard J

    2004-06-15

    The concentrations of phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, and hexachlorobenzene (HCB) were measured in spruce needles at 36 sites in eastern Alaska during early spring. Concentrations of each polycyclic aromatic hydrocarbon (PAH) varied by an order of magnitude. Samples taken from near the city of Fairbanks had higher concentrations than samples taken from more rural areas. Anthropogenic activities near Fairbanks are most likely a source of PAHs. Variation in the concentration ratios of isomeric PAHs indicates the relative importance of combustion and petrogenic sources. The relative combustion contribution is largest in coastal samples and smallest near Fairbanks. In contrast, the concentration of HCB varied by only a factor of 2. Lipid content of needles and distance from the coast were the major factors correlated with the concentration of HCB.

  19. Performance of the Forest Vegetation Simulator in managed white spruce plantations influenced by eastern spruce budworm in northern Minnesota

    Treesearch

    Matthew B. Russell; Anthony W. D' Amato; Michael A. Albers; Christopher W. Woodall; Klaus J. Puettmann; Michael R. Saunders; Curtis L. VanderSchaaf

    2015-01-01

    Silvicultural strategies such as thinning may minimize productivity losses from a variety of forest disturbances, including forest insects. This study analyzed the 10-year postthinning response of stands and individual trees in thinned white spruce (Picea glauca [Moench] Voss) plantations in northern Minnesota, USA, with light to moderate defoliation...

  20. Detection of single and mixed covert baculovirus infections in eastern spruce budworm, Choristoneura fumiferana populations.

    PubMed

    Kemp, Elizabeth M; Woodward, David T; Cory, Jenny S

    2011-07-01

    We surveyed for covert baculovirus infections in the eastern spruce budworm, Choristoneura fumiferana (Clemens) and compared the prevalence of virus detected in a laboratory and a field population. DNA was extracted from budworm adults and then PCR with degenerate primers was used to identify individuals carrying baculovirus DNA. Multiplex PCR was then applied to the positive samples to distinguish between the multiple baculovirus types that could potentially be found in C. fumiferana populations. Covert infections were found in both the laboratory and the field population of C. fumiferana, although the frequency of infection and the composition of viruses found were very different. Overall 28% of insects from the laboratory population were positive for baculovirus DNA. Individual adults supported both single and mixed covert infections with CfMNPV plus CfDEFNPV, CfDEFNPV plus a GV and mixtures of all three viruses together. However, the majority of insects supported single virus infections, and surprisingly this virus was CfDEFNPV, a virus that is reported not to have per os activity in C. fumiferana larvae. Insects from field populations showed a very different pattern; 70.5% of individuals were baculovirus positive and all of these were positive for CfDEFNPV only.

  1. The isolated red spruce communities of Virginia and West Virginia

    Treesearch

    Harold S. Adams; Steven Stephenson; Adam W. Rollins; Mary Beth. Adams

    2010-01-01

    Quantitative data on the composition and structure of coniferous forests containing red spruce in the mountains of central and southwestern Virginia and eastern central West Virginia, based on sampling carried out in 67 stands during the 1982 to 1984 field seasons, are provided. The average importance value ([relative basal area + relative density/2]) of red spruce was...

  2. Total and pyrogenic carbon stocks in black spruce forest floors from eastern Canada

    NASA Astrophysics Data System (ADS)

    Soucemarianadin, Laure; Quideau, Sylvie; MacKenzie, M. Derek; Munson, Alison; Boiffin, Juliette; Bernard, Guy; Wasylishen, Roderick

    2016-04-01

    In boreal forests, pyrogenic carbon (PyC), a by-product of recurrent wildfires, is an important component of the global soil C pool, although precise assessment of boreal PyC stock is scarce. In this study including 14 fire sites spreading over 600 km in the Quebec province, our aim was to better estimate total C stock and PyC stock in forest floors of Eastern Canada boreal forests. We also investigated the environmental conditions controlling the stocks and characterized the composition of the various forest floor layers. We analyzed the forest floor samples that were collected from mesic black spruce sites recently affected by fire (3-5 years) using elemental analysis and solid state 13C nuclear magnetic resonance (NMR) spectroscopy. PyC content was further estimated using a molecular mixing model on the 13C NMR data. Total C stock in forest floors averaged 5.7 ± 2.9 kg C/m2 and PyC stock 0.6 ± 0.3 kg C/m2. Total C stock was under control of the position in the landscape, with a greater accumulation of organic material on northern aspects and lower slope positions. In addition, total stock was significantly higher in spruce-dominated forest floors than in stands where jack pine was dominant. The PyC stock was significantly related to the atomic H/C ratio (R2 = 0.84) of the different organic layers. 13C NMR spectroscopy revealed a large increase in aromatic carbon in the deepest forest floor layer (humified H horizon) at the organic-mineral soil interface. The majority of the PyC stock was located in this horizon and had been formed during past high severity fires rather than during the most recent fire event. Conversely, the superficial "fresh" PyC layer, produced by early-season wildfires in 2005-2007, had NMR spectra fairly similar to unburned forest floors and comparatively low PyC stocks.

  3. Does post-fire abiotic habitat filtering create divergent plant communities in black spruce forests of eastern Canada?

    PubMed

    Collier, Laura C Siegwart; Mallik, Azim U

    2010-10-01

    We investigated the role of post-fire residual organic matter (ROM) thickness as a driver of community assembly in eastern Newfoundland. We hypothesized that if post-fire community assembly is predominantly controlled by ROM thickness (an abiotic habitat filter), then post-fire species composition and functional traits should correspond to the depth and distribution of ROM. However, if species interactions (biotic filter) are the primary constraints on community assembly, then post-fire species composition and their functional traits should be independent of the depth and distribution of ROM. We tested these predictions in three relatively mature plant communities, Kalmia angustifolia heath, black spruce (Picea mariana)-Kalmia shrub savannah and black spruce forest. Through pre-fire stand reconstruction, we found evidence that the three communities originated from black spruce forest. ROM thickness in heath was almost twice that of shrub savannah and six times more than forest, suggesting a gradient in fire severity. Distribution of ROM corresponded to patterns in vegetation dominance, where thick ROM (>2 cm) filtered out black spruce in favour of Kalmia. ROM thickness was a strong predictor of vegetation composition and function between heath and forest, but this was not found between the shrub savannah and forest. We attribute this to species interactions and allelopathy, which may have become important when ROM thickness was suitable for both seed (black spruce) and vegetative (Kalmia) regenerating species. Thus, priority effects or "who came first" may have lead to shrub savannah formation when ROM thickness was ~2 cm. We conclude that abiotic habitat filtering of thick ROM (>2 cm) on (primarily) species' regeneration traits was the primary driver of community divergence from forest to heath and shrub savannah.

  4. Vertical structure of evapotranspiration at a spruce forest site

    NASA Astrophysics Data System (ADS)

    Staudt, K.; Falge, E.; Serafimovich, A.; Pyles, D.; Foken, T.

    2009-12-01

    The Advanced Canopy-Atmosphere-Soil Algorithm (ACASA) was used to model the turbulent fluxes of heat, water vapor and momentum as well as the carbon dioxide exchange within and above a spruce canopy at the FLUXNET-station Waldstein-Weidenbrunnen (DE-Bay) in the Fichtelgebirge mountains in northern Bavaria, Germany. ACASA is a multilayer canopy-surface-layer model that incorporates a third-order closure method to calculate turbulent transfer within and above the canopy and was developed at the University of California, Davis. Within the EGER (ExchanGE processes in mountainous Regions) project, comprehensive micrometeorological and plant physiological measurements were performed during two intensive observation periods in fall 2007 and summer 2008. This data base allowed us to extensively test the ability of the ACASA model to simulate the exchange of energy and matter at our site. Here, the vertical structure of evapotranspiration within and above the canopy for a few days is investigated in detail. The ACASA model provides profiles of all components of evapotranspiration, such as transpiration and evaporation from the soil, and estimates the interception of precipitation and the corresponding evaporation from wet plant surfaces. Fluxes of momentum, heat, carbon dioxide and water vapor were measured with six eddy-covariance systems below, within and above the canopy on a 36 m high tower. Furthermore, xylem sapflow measurements at six heights within the canopy were performed for the determination of canopy transpiration. This combination of multilevel measurements allowed us to estimate all components of evapotranspiration of and within the spruce forest. Model results and measurements of evapotranspiration are analyzed with regard to the partitioning between its components as well as between the canopy layers. Furthermore, the ability of the ACASA model to reproduce evapotranspiration profiles for different exchange regimes of the subcanopy and the canopy is

  5. Soil-mediated effects of atmospheric deposition on eastern US spruce-fir forests. Book chapter

    SciTech Connect

    Johnson, D.W.; Fernandez, I.J.

    1992-01-01

    The coincident observation of Waldsterben in Germany and red spruce decline in the northeastern U.S. has naturally led to some speculation that similar mechanisms may be involved. In the German situation, soil-mediated hypotheses played (and still play) a major role; namely, soil acidification and aluminum toxicity and base cation deficiencies. In the red spruce case, there has been much concern that cation deficiencies and/or aluminum toxicity may also play a major role. The purpose of this chapter is to: (1) review some of the basic properties of soils, nutrition, and nutrient cycling in spruce-fir and fir ecosystems, both in the polluted and in the relatively unpolluted regions of the U.S. and Canada, and (2) to evaluate several soil acidity-related hypotheses for red spruce decline.

  6. Spruce-fir management and spruce budworm; SAF region VI technical conference

    Treesearch

    Daniel Schmitt; ed.

    1985-01-01

    Presents a technical update of the management of spruce-fir forests. Integrated management of eastern spruce budworm is not yet a reality. The ecological, social, and economic knowledge needed to develop an integrated management system is not available. The conference was designed to move individuals to a higher level of spruce budworm management in the eastern spruce-...

  7. The effects of a western spruce budworm outbreak on the dead wood component in relation to ownership in forests of eastern Oregon

    Treesearch

    David. Azuma

    2010-01-01

    Forest Inventory and Analysis data were used to investigate the effects of a severe western spruce budworm outbreak on the dead wood component of forests in 11 counties of eastern Oregon for two time periods. The ownership and the level of damage (as assessed by aerial surveys) affected the resulting down woody material and standing dead trees. The pattern of coarse...

  8. Impact of eastern dwarf mistletoe (Arceuthobium pusillum) on host white spruce (Picea glauca) development, growth and performance across multiple scales.

    PubMed

    Logan, Barry A; Reblin, Jaret S; Zonana, David M; Dunlavey, Ryan F; Hricko, Carolyn R; Hall, Adam W; Schmiege, Stephanie C; Butschek, Ross A; Duran, Kristy L; Emery, R J Neil; Kurepin, Leonid V; Lewis, James D; Pharis, Richard P; Phillips, Nathan G; Tissue, David T

    2013-04-01

    Infection by eastern dwarf mistletoe (Arceuthobium pusillum) modifies needle and branch morphology and hastens white spruce (Picea glauca) mortality. We examined potential causal mechanisms and assessed the impacts of infection-induced alterations to host development and performance across scales ranging from needle hormone contents to bole expansion. Needles on infected branches (IBs) possessed higher total cytokinin (CK) and lower abscisic acid contents than needles on uninfected branches (UBs). IBs exhibited greater xylem growth than same-aged UBs, which is consistent with the promotive effect of CKs on vascular differentiation and organ sink strength. Elevated CK content may also explain the dense secondary and tertiary branching observed at the site of infection, i.e. the formation of 'witches' brooms' with significantly lower light capture efficiencies. Observed hormone perturbations were consistent with higher rates of transpiration, lower water use efficiencies (WUEs) and more negative needle carbon isotope ratios observed for IBs. Observed reductions in needle size allowed IBs to compensate for reduced hydraulic conductivity. Severe infections resulted in dramatically decreased diameter growth of the bole. It seems likely that the modifications to host hormone contents by eastern dwarf mistletoe infection led white spruce trees to dedicate a disproportionate fraction of their photoassimilate and other resources to self-shaded branches with low WUE. This would have decreased the potential for fixed carbon accumulation, generating a decline in the whole-tree resource pool. As mistletoe infections grew in size and the number of IBs increased, this burden was manifested as increasingly greater reductions in bole growth.

  9. BVOC emission in Norway spruce: the effect of stand structure, high temperature and ozone levels.

    NASA Astrophysics Data System (ADS)

    Pallozzi, Emanuele; Guidolotti, Gabriele; Večeřová, Kristýna; Esposito, Raffaela; Lusini, Ilaria; Juráň, Stanislav; Urban, Otmar; Calfapietra, Carlo

    2015-04-01

    Norway spruce (Picea abies L.) is a widely distributed conifer species in the boreal zone and mountain areas of central Europe and is a moderate emitter of volatile organic compounds (BVOC). Although the vaporization and diffusion processes from resin ducts were generally considered to be the main processes for monoterpene emissions in conifers, recently it has been showed that a significant portion (up to one third) of monoterpene emissions of Norway spruce can originate from novel biosynthesis, thus depending on photosynthetic processes. For this reason, both biosynthesis and emission are strongly influenced by the environment and the stand structure. They increase with both increasing light and temperature during the warmer periods, although those are the periods with the higher ozone concentration that usually act as an inhibitor of both assimilation and isoprenoids synthesis and emission. On the other hand, stand structure can play an important role, because the photosynthetic capacity is influenced by temperature and light conditions through the canopy. In order to assess the effects of stand structure, temperature and ozone on isoprenoids emission of Norway spruce we carried out field and laboratory experiments. In the experimental field campaigns we measured: assimilation and BVOC emission from needles of sun and shade layers within the canopy of the spruce forest present at the Bily Kriz experimental research site (Moravian-Silesian Beskydy Mountains, 49° 33' N, 18° 32' E, NE of Czech Republic, 908 m a.s.l.). Moreover in the same layers we measured continuously concentration of BVOCs in the air using a PTR-TOF-MS. In laboratory we analyzed the effects of short-term exposure to high temperature and high ozone concentrations on branches of spruce trees collected at the Bily Kriz experimental research site. Preliminary results show that in Norway spruce both stand structure and environmental conditions influenced the gas exchange and BVOC emission rates

  10. Response of aluminum solubility to elevated nitrification in soil of a red spruce stand in eastern Maine

    USGS Publications Warehouse

    Lawrence, G.B.; David, M.B.

    1997-01-01

    Elevated concentrations of soluble Al can impair tree growth and be toxic to aquatic biota, but effects of acidic deposition on Al solubility in forest soils are only partially understood because of complex interactions with H+ and organic matter. We therefore evaluated Al solubility in two red spruce stands in eastern Maine, one of which received dry (NH4)2SO4 at a rate of 1800 equiv ha-1 yr-1 during 19891995. Samples of soil (Spodosol Oa and Bh horizons) and soil solution were collected on five dates from 1992 to 1995. The treatment elevated nitrification, causing an increase in acid input that led to inorganic Al concentrations of greater than 60 ??mol L-1 in both the Oa and Bh horizons. Solubility of Al was also lower in the Bh horizon of the treated stand than in the reference stand, a response related to higher DOC concentrations in the treated stand. Concentrations of CuCl2 and pyrophosphate-extractable Al were higher in the Oa horizon of the treated watershed than the reference stand, a result of accelerated weathering of mineral particles caused by lower solution pH in the treated stand (3.47) than in the reference stand (3.69). Dissolved Al concentrations in these soils are the result of complex mechanisms through which mineral matter, organic matter, and pH interact to control Al solubility; mechanisms that are not incorporated in current Al solubility models.

  11. The current status of red spruce in the eastern United States: distribution, population trends, and environmental drivers

    Treesearch

    Gregory Nowacki; Robert Carr; Michael. Van Dyck

    2010-01-01

    Red spruce (Picea rubens Sarg.) was affected by an array of direct (logging, fire, and grazing) and indirect human activities (acid deposition) over the past centuries. To adequately assess past impacts on red spruce, thus helping frame its restoration potential, requires a clear understanding of its current status. To achieve this, Forest and...

  12. Reproductive barriers and hybridity in two spruces, Picea rubens and Picea mariana, sympatric in eastern North America

    Treesearch

    John E. Major; Alex Mosseler; Kurt H. Johnsen; Om P. Rajora; Debby C. Barsi; K.-H. Kim; J.-M. Park; Moira Campbell

    2005-01-01

    Hybridization between red spruce (Picea rubens Sarg.) and black spruce (Picea mariana (Mill.) BSP), lateand early-successional species, respectively, has resulted in identification and management problems. We investigated the nature and magnitude of reproductive and life-cycle success barriers in controlled intra- and inter-...

  13. Oldest known Engelmann spruce

    Treesearch

    Peter M. Brown; Wayne D. Shepperd; Christopher C. Brown; Stephen A. Mata; Douglas L. McClain

    1995-01-01

    Age structure in a stand of very old-age Engelmann spruce is described. The site is at 3,505 m near treeline in the Fraser Experimental Forest in central Colorado. The site contains the oldest Engelmann spruce trees yet reported in the literature; the oldest tree is at least 852 years of age.

  14. Can Landscape-scale management influence insect outbreak dynamics? A natural experiment for eastern spruce budworm

    Treesearch

    Brian R. Sturtevant; V. Quinn; L.E. Robert; D. Kneeshaw; P. James; M.-J. Fortin; P. Wolter; P. Townsend; B. Cooke; D. Anderson

    2010-01-01

    The balance of evidence suggests forest insect outbreaks today are more damaging than ever because of changes in forest composition and structure induced by fire suppression and post-harvest proliferation of tree species intolerant to herbivory. We hypothesized that landscape connectivity of acceptable host trees increases defoliator population connectivity, altering...

  15. SABATH methyltransferases from white spruce (Picea glauca): gene cloning, functional characterization and structural analysis.

    PubMed

    Zhao, Nan; Boyle, Brian; Duval, Isabelle; Ferrer, Jean-Luc; Lin, Hong; Seguin, Armand; MacKay, John; Chen, Feng

    2009-07-01

    Known members of the plant SABATH family of methyltransferases have important biological functions by methylating hormones, signalling molecules and other metabolites. While all previously characterized SABATH genes were isolated from angiosperms, in this article, we report on the isolation and functional characterization of SABATH genes from white spruce (Picea glauca [Moench] Voss), a gymnosperm. Through EST database search, three genes that encode proteins significantly homologous to known SABATH proteins were identified from white spruce. They were named PgSABATH1, PgSABATH2 and PgSABATH3, respectively. Full length cDNAs of these three genes were cloned and expressed in Escherichia coli. The E. coli-expressed recombinant proteins were tested for methyltransferase activity with a large number of compounds. While no activity was detected for PgSABATH2 and PgSABATH3, PgSABATH1 displayed the highest level of catalytic activity with indole-3-acetic acid (IAA). PgSABATH1 was, therefore, renamed PgIAMT1. Under steady-state conditions, PgIAMT1 exhibited apparent Km values of 18.2 microM for IAA. Homology-based structural modelling of PgIAMT1 revealed that the active site of PgIAMT1 is highly similar to other characterized IAMTs from angiosperms. PgIAMT1 showed expression in multiple tissues, with the highest level of expression detected in embryonic tissues. During somatic embryo maturation, a significant reduction in PgIAMT1 transcript levels was observed when developing cotyledons become apparent which is indicative of mature embryos. The biological roles of white spruce SABATH genes, especially those of PgIAMT1, and the evolution of the SABATH family are discussed.

  16. Structure and Carbon Distribution of Well- and Poorly-Drained Black Spruce Fire Chronosequences

    NASA Astrophysics Data System (ADS)

    Wang, C.; Bond-Lamberty, B.; Gower, S. T.

    2002-12-01

    The objectives of this study were to: (1) examine structure changes along a boreal black spruce (Picea mariana (Mill.) BSP) fire chronosequence in northern Manitoba, Canada; (2) quantify temporal dynamics in C content across the chronosequence; and (3) compare the C distribution for these stands on contrasting soil drainages. The experimental design was a well-drained (dry) and poorly-drained (wet) black spruce fire chronosequences comprised of seven stands that burned between 1998 and 1870. Tree species diversity was greater in the younger stands, and by 71 years after fire black spruce comprised >88% and 83% of total basal area for the dry and wet stands, respectively. Feather moss replaced sphagnum during succession in the dry stands, whereas there were no clear patterns in the wet chronosequence. Total vegetation C content (aboveground + belowground) increased with forest succession, ranging from 1.3 to 83.3 t C ha-1 for the dry stands and 0.6 to 37.4 t C ha-1 for the wet stands. Mean annual aboveground C accumulation rates (Δ CA) peaked in the 71- and 36-year-old dry and wet stands, respectively. Overstory and live moss C contents increased with stand age. The total root : shoot ratio was fairly consistent (0.235 +/- 0.046) after 37 years following fire. The basal area, vegetation C content, and Δ CA were significantly greater (α = 0.05) in the dry than wet stands, but the C contents in bryophyte and forest floor were significantly less in the dry stands. Our results emphasize the need to incorporate disturbance and soil drainage in large-scale boreal forest C models.

  17. Modeling spruce budworm population revisited: impact of physiological structure on outbreak control.

    PubMed

    Vaidya, Naveen K; Wu, Jianhong

    2008-04-01

    Understanding the dynamics of spruce budworm population is very important for the protection of spruce and balsam fir trees of North American forests, and a full understanding of the dynamics requires careful consideration of the individual physiological structures that is essential for outbreak control. A model as a delay differential equation is derived from structured population system, and is validated by comparing simulation results with real data from the Green River area of New Brunswick (Canada) and with the periodic outbreaks widely observed. Analysis of the equilibrium stability and examination of the amplitudes and frequencies of periodic oscillations are conducted, and the effect of budworm control strategies such as mature population control, immature population control and predation by birds are assessed. Analysis and simulation results suggest that killing only budworm larvae might not be enough for the long-term control of the budworm population. Since the time required for development during the inactive stage (from egg to second instar caterpillar) causes periodic outbreak, a strategy of reducing budworms in the inactive stage, such as removing egg biomass, should also be implemented for successful control.

  18. Proceedings of the US/FRG research symposium: effects of atmospheric pollutants on the spruce-fir forests of the Eastern United States and the Federal Republic of Germany

    Treesearch

    Gerard, tech. coord. Hertel; Gerard Hertel

    1988-01-01

    Includes 66 papers presented at the US/FRG research symposium: effects of atmospheric pollutants on the spruce-fir forests of the Eastern United States and the Federal Republic of Germany, which was held October 19-23, 1987, in Burlington, Vermont.

  19. Losses associated with Douglas-fir and true fir tops killed by western spruce budworm in eastern Washington.

    Treesearch

    Paul E. Aho

    1984-01-01

    A sample of 133 Douglas-firs (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and 69 true firs (Abies spp.) with dead tops caused by defoliation by the western spruce budworm (Choristoneura occidentalis Freeman) were felled, dissected, and examined for height loss and incidence and...

  20. Investigation of changes in structure and thermodynamic of spruce budworm antifreeze protein under subfreezing temperature

    NASA Astrophysics Data System (ADS)

    Nguyen, Hung; Le, Ly

    2017-01-01

    The aim of this theoretical work is to investigate of the changes in structure and thermodynamics of spruce budworm antifreeze protein (sbAFP) at low temperatures by using molecular dynamics simulation. The aqueous solution will form ice crystal network under the vaguely hexagonal shape at low temperature and fully represented the characteristics of hydrophobic interaction. Like ice crystal network, the cyclohexane region (including cyclohexane molecules) have enough of the characteristics of hydrophobic interaction. Therefore, in this research the cyclohexane region will be used as a representation of ice crystal network to investigate the interactions of sbAFP and ice crystal network at low temperature. The activity of sbAFP in subfreezing environment, therefore, can be clearly observed via the changes of the hydrophobic (cyclohexane region) and hydrophilic (water region) interactions. The obtained results from total energies, hydrogen bond lifetime correlation C(t), radial distribution function, mean square deviation and snapshots of sbAFP complexes indicated that sbAFP has some special changes in structure and interaction with water and cyclohexane regions at 278 K, as being transition temperature point of water molecules in sbAFP complex at low temperatures, which is more structured and support the experimental observation that the sbAFP complex becomes more rigid as the temperature is lowered.

  1. Investigation of changes in structure and thermodynamic of spruce budworm antifreeze protein under subfreezing temperature

    PubMed Central

    Nguyen, Hung; Le, Ly

    2017-01-01

    The aim of this theoretical work is to investigate of the changes in structure and thermodynamics of spruce budworm antifreeze protein (sbAFP) at low temperatures by using molecular dynamics simulation. The aqueous solution will form ice crystal network under the vaguely hexagonal shape at low temperature and fully represented the characteristics of hydrophobic interaction. Like ice crystal network, the cyclohexane region (including cyclohexane molecules) have enough of the characteristics of hydrophobic interaction. Therefore, in this research the cyclohexane region will be used as a representation of ice crystal network to investigate the interactions of sbAFP and ice crystal network at low temperature. The activity of sbAFP in subfreezing environment, therefore, can be clearly observed via the changes of the hydrophobic (cyclohexane region) and hydrophilic (water region) interactions. The obtained results from total energies, hydrogen bond lifetime correlation C(t), radial distribution function, mean square deviation and snapshots of sbAFP complexes indicated that sbAFP has some special changes in structure and interaction with water and cyclohexane regions at 278 K, as being transition temperature point of water molecules in sbAFP complex at low temperatures, which is more structured and support the experimental observation that the sbAFP complex becomes more rigid as the temperature is lowered. PMID:28106056

  2. The effects of partial cutting on stand structure and growth of western hemlock-Sitka spruce stands in southeast Alaska

    USGS Publications Warehouse

    Deal, R.L.; Tappeiner, J.C.

    2002-01-01

    The effects of partial cutting on species composition, new and residual-tree cohorts, tree size distribution, and tree growth was evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 12-96 years ago, when 16-96% of the former stand basal area was removed. Partial cutting maintained stand structures similar to uncut old-growth stands, and the cutting had no significant effects on tree species composition. The establishment of new-tree cohorts was positively related to the proportion of basal-area cut. The current stand basal area, tree species composition, and stand growth were significantly related to trees left after harvest (p < 0.001). Trees that were 20-80 cm dbh at the time of cutting had the greatest tree-diameter and basal-area growth and contributed the most to stand growth. Diameter growth of Sitka spruce and western hemlock was similar, and the proportion of stand basal-area growth between species was consistent for different cutting intensities. Concerns about changing tree species composition, lack of spruce regeneration, and greatly reduced stand growth and vigor with partial cuts were largely unsubstantiated. Silvicultural systems based on partial cutting can provide rapidly growing trees for timber production while maintaining complex stand structures with mixtures of spruce and hemlock trees similar to oldgrowth stands.

  3. Hoverfly (syrphidae) communities respond to varying structural retention after harvesting in canadian peatland black spruce forests.

    PubMed

    Deans, A M; Smith, S M; Malcolm, J R; Crins, W J; Bellocq, M I

    2007-04-01

    Variable retention harvesting (VRH), in which trees are removed at variable intensity and spatial configuration across the landscape, retains greater forest structural heterogeneity than traditional clear-cut harvesting and is being recommended as an alternative for sustainable management of the boreal forest. Little is known about its effects on forest fauna; thus, we studied the influence of one type of VRH (harvesting with advanced regeneration [HARP]) on the Syrphidae (Diptera) community in northern Ontario forests of peatland black spruce (Picea mariana). We examined the effects of varying structural retention (from unharvested through partial retention to clear-cut) on syrphid species richness and abundance, and abundance of functional assemblages. Greater species richness and population abundances were found generally in harvested than in unharvested forests. Overall species richness and the abundance of four species (Platycheirus rosarum, Toxomerus marginatus, Xylota annulifera, and X. tuberculata) and larval predators were all higher in both clear-cut sites and those with structural retention than in unharvested sites. Similarly, overall species richness and the abundance of nine species were higher in clear-cut than in unharvested sites. Species responses are discussed in an ecological context. Differences among the levels of forest retention harvesting were relatively minor compared with those of the clear-cut and unharvested area, suggesting that local habitat characteristics may play a more important role in determining the syrphid community than the landscape configuration. However, a landscape level effect was evident, suggesting that syrphids may be useful in reflecting changes in stand structure at the landscape scale.

  4. Diurnal changes in the dielectric properties and water status of eastern hemlock and red spruce from Howland, ME

    NASA Technical Reports Server (NTRS)

    Salas, W. A.; Ranson, K. J.; Rock, B. N.; Moss, D. M.

    1991-01-01

    The diurnal characteristics of microwave dielectric properties and water potential of two conifer species were investigated in July and September, 1990. P-band and C-band radial dielectric profiles of hemlock and red spruce, as well as hemlock diurnal water potential and dielectric profiles, are presented. The resulting radial dielectric profiles matched the regions of the functional sapwood (water transport component of the active xylem) in both species such that the sapwood was characterized by a higher dielectric than the bark and heartwood tissues. This is probably due to characteristic differences in the water content of each tissue. As the hemlocks progressed through their diurnal water potential pattern, the dielectric profile remained static until mid-afternoon. As the tension in the water column relaxed (2 to 3 bars) the dielectric constant decreased by 30 to 40 percent. There are several possible explanations for this phenomenon, and these may relate to the dependency of the dielectric measurements on temperature, salinity, and volumetric water content.

  5. Diurnal changes in the dielectric properties and water status of eastern hemlock and red spruce from Howland, ME

    NASA Technical Reports Server (NTRS)

    Salas, W. A.; Ranson, K. J.; Rock, B. N.; Moss, D. M.

    1991-01-01

    The diurnal characteristics of microwave dielectric properties and water potential of two conifer species were investigated in July and September, 1990. P-band and C-band radial dielectric profiles of hemlock and red spruce, as well as hemlock diurnal water potential and dielectric profiles, are presented. The resulting radial dielectric profiles matched the regions of the functional sapwood (water transport component of the active xylem) in both species such that the sapwood was characterized by a higher dielectric than the bark and heartwood tissues. This is probably due to characteristic differences in the water content of each tissue. As the hemlocks progressed through their diurnal water potential pattern, the dielectric profile remained static until mid-afternoon. As the tension in the water column relaxed (2 to 3 bars) the dielectric constant decreased by 30 to 40 percent. There are several possible explanations for this phenomenon, and these may relate to the dependency of the dielectric measurements on temperature, salinity, and volumetric water content.

  6. Subsurface structure of the eastern Arkoma basin

    SciTech Connect

    Vanarsdale, R.B. ); Schweig, E.S. III )

    1990-07-01

    Analysis of 425 km of seismic reflection data in the eastern Arkoma basin reveals a structure and history quite different from those previously reported for the Arkoma basin. The eastern Arkoma basin has three structural styles that formed in the following chronological order: deep, steep normal faults; shallow listric normal faults; and thrust faults. The origin of the structural styles and the Paleozoic history of the eastern Arkoma basin may be summarized as follows. Late Proterozoic or Early Cambrian rifting was followed by deposition of Cambrian through Upper Mississippian strata on a passive plate margin. The Mississippian-Pennsylvanian boundary marks a time of major down-to-the-south normal faulting with coincident folding of the footwall blocks and truncation of the faulted and folded terrain by a pre-Morrowan (Mississippian-Pennsylvanian) unconformity. The unconformity slopes southward and steepens locally across the erosionally truncated footwall blocks. During the Pennsylvanian, down-to-the-south listric normal faults cut the Atokan and Morrowan sections and merged with, but did not displace, the steeper segments of the sub-Morrowan unconformity. Surface folds north of the Ross Creek thrust are rollover anticlines overlying these listric normal faults. Major deformation in the eastern Arkoma basin terminated with emplacement of the Ross Creek thrust in the Late Pennsylvanian. 4 figs., 1 tab.

  7. Nutritional pyhsiology of the eastern spruce budworm, Choristoneura fumiferana, infected with Nosema fumiferanae, and interactions with dietary nitrogen

    Treesearch

    Leah S. Bauer; G.L. Nordin

    1988-01-01

    Female eastern spurce budworm larvae, Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae), inoculated with a medium lethal spore dosage of the microsporidium. Nosema fumiferanae (Thomson) exhibited significant reductions in a consumptive index (CI), nitrogen consumptive index (NCI), relative growth rate (RGR), and gross(...

  8. Hydraulic and mechanical properties of young Norway spruce clones related to growth and wood structure.

    PubMed

    Rosner, Sabine; Klein, Andrea; Müller, Ulrich; Karlsson, Bo

    2007-08-01

    Stem segments of eight five-year-old Norway spruce (Picea abies (L.) Karst.) clones differing in growth characteristics were tested for maximum specific hydraulic conductivity (k(s100)), vulnerability to cavitation and behavior under mechanical stress. The vulnerability of the clones to cavitation was assessed by measuring the applied air pressure required to cause 12 and 50% loss of conductivity (Psi(12), Psi(50)) and the percent loss of conductivity at 4 MPa applied air pressure (PLC(4MPa)). The bending strength and stiffness and the axial compression strength and stiffness of the same stem segments were measured to characterize wood mechanical properties. Growth ring width, wood density, latewood percentage, lumen diameter, cell wall thickness, tracheid length and pit dimensions of earlywood cells, spiral grain and microfibril angles were examined to identify structure-function relationships. High k(s100) was strongly and positively related to spiral grain angle, which corresponded positively to tracheid length and pit dimensions. Spiral grain may reduce flow resistance of the bordered pits of the first earlywood tracheids, which are characterized by rounded tips and an equal distribution of pits along the entire length. Wood density was unrelated to hydraulic vulnerability parameters. Traits associated with higher hydraulic vulnerability were long tracheids, high latewood percentage and thick earlywood cell walls. The positive relationship between earlywood cell wall thickness and vulnerability to cavitation suggest that air seeding through the margo of bordered pits may occur in earlywood. There was a positive phenotypic and genotypic relationship between k(s100) and PLC(4MPa), and both parameters were positively related to tree growth rate. Variability in mechanical properties depended mostly on wood density, but also on the amount of compression wood. Accordingly, hydraulic conductivity and mechanical strength or stiffness showed no tradeoff.

  9. Recent field research experience with B.t. against spruce budworm in the eastern U.S.

    Treesearch

    John B. Dimond

    1985-01-01

    Recent testing in the eastern U. S. has led quickly to the adoption of 12 BIU/acre as the best operational dosage rate, with operational spray emission rates reduced to a quart or less per acre. Some recent work suggests that older larval instars of the budworm are highly susceptible to B.t. sprays, and the effective "spray window" can be broadened when...

  10. Effects of warming on the structure and function of a boreal black spruce forest

    SciTech Connect

    Stith T.Gower

    2010-03-03

    A strong argument can be made that there is a greater need to study the effect of warming on boreal forests more than on any other terrestrial biome. Boreal forests, the second largest forest biome, are predicted to experience the greatest warming of any forest biome in the world, but a process-based understanding of how warming will affect the structure and function of this economically and ecologically important forest biome is lacking. The effects of warming on species composition, canopy structure and biogeochemical cycles are likely to be complex; elucidating the underlying mechanisms will require long-term whole-ecosystem manipulation to capture all the complex feedbacks (Shaver et al. 2000, Rustad et al. 2001, Stromgren 2001). The DOE Program for Ecosystem Research funded a three year project (2002-2005) to use replicated heated chambers on soil warming plots in northern Manitoba to examine the direct effects of whole-ecosystem warming. We are nearing completion of our first growing season of measurements (fall 2004). In spite of the unforeseen difficulty of installing the heating cable, our heating and irrigation systems worked extremely well, maintaining environmental conditions within 5-10% of the specified design 99% of the time. Preliminary data from these systems, all designed and built by our laboratory at the University of Wisconsin, support our overall hypothesis that warming will increase the carbon sink strength of upland boreal black spruce forests. I request an additional three years of funding to continue addressing the original objectives: (1) Examine the effect of warming on phenology of overstory, understory and bryophyte strata. Sap flux systems and dendrometer bands, monitored by data loggers, will be used to quantify changes in phenology and water use. (2) Quantify the effects of warming on nitrogen and water use by overstory, understory and bryophytes. (3) Compare effects of warming on autotrophic respiration and above- and belowground

  11. Elicitor-Induced Spruce Stress Lignin (Structural Similarity to Early Developmental Lignins).

    PubMed Central

    Lange, B. M.; Lapierre, C.; Sandermann, H.

    1995-01-01

    Suspension cultures of Picea abies (L.) Karst released polymeric material into the culture medium when treated with an elicitor preparation from the spruce needle pathogen Rhizosphaera kalkhoffii. The presence of lignin (about 35%, w/w) was demonstrated by phloroglucinol/HCI reactivity and quantitation with thioglycolic acid. Carbohydrate (about 14%, w/w) and protein (about 32%, w/w) were also detected. Amino acid analysis revealed that hydroxyproline and proline predominated. Thioacidolysis and subsequent Raney nickel desulfurization allowed the analysis of lignin-building units and interunit bonds. Compared with spruce wood lignin, an approximately 20-fold higher relative amount of p-hydroxyphenyl units was determined. A high content of p-hydroxyphenyl units is typical for certain developmental lignins, such as conifer compression wood and middle lamella lignins, as well as all induced cell culture lignins so far analyzed. Cross-linkages of the pinoresinol type ([beta]-[beta]) in the excreted cell culture lignin were markedly increased, whereas [beta]-1 interunit linkages were decreased relative to spruce wood lignin. The amount and nature of cross-linkages were shown to be intermediate between those in wood lignin and in enzymatically prepared lignins. In summary, the elicitor-induced stress lignin was excreted as a lignin-extensin complex that closely resembled early developmental lignins. PMID:12228544

  12. Can nutrient limitations explain low and declining white spruce growth near the Arctic treeline in the eastern Brooks Range, Alaska?

    NASA Astrophysics Data System (ADS)

    Ellison, S.; Sullivan, P. F.

    2014-12-01

    The position of the Arctic treeline is of critical importance for global carbon cycling and surface energy budgets. However, controls on tree growth at treeline remain uncertain. In the Alaskan Brooks Range, 20th century warming has caused varying growth responses among treeline trees, with trees in the west responding positively, while trees in the east have responded negatively. The prevailing explanation of this trend ascribes the negative growth response to warming-induced drought stress in the eastern Brooks Range. However, recent measurements of carbon isotope discrimination in tree rings, xylem sap flow and needle gas exchange suggest that drought stress cannot explain these regional growth declines. Additionally, evidence from the western Brooks Range suggests that nutrient availability, rather than drought stress, may be the proximate control on tree growth. In this study, we investigated the hypothesis that low and declining growth of eastern Brooks Range trees is due to low and declining soil nutrient availability, which may continue to decrease with climate change as soils become drier and microbial activity declines. We compared microclimate, tree performance, and a wide range of proxies for soil nutrient availability in four watersheds along a west-east transect in the Brooks Range during the growing seasons of 2013 and 2014. We hypothesized that soil nutrient availability would track closely with the strong west-east precipitation gradient, with higher rainfall and greater soil nutrient availability in the western Brooks Range. We expected to find that soil water contents in the west are near optimum for nitrogen mineralization, while those in the east are below optimum. Needle nitrogen concentration, net photosynthesis, branch extension growth, and growth in the main stem are expected to decline with the hypothesized decrease in soil nutrient availability. The results of our study will elucidate the current controls on growth of trees near the

  13. Crustal Structure in Central-Eastern Greenland

    NASA Astrophysics Data System (ADS)

    Shulgin, A.; Thybo, H.

    2013-12-01

    We present the seismic structure in the interior of Greenland based on the first measurements by the seismic refraction/wide angle reflection method. Previous seismic surveys have only been carried out offshore and near the coast of Greenland, where the crustal structure is affected by oceanic break-up and may not be representative of the interior of the island. Acquisition of geophysical data onshore Greenland is logistically complicated by the presence of an up to 3.4 km thick ice sheet, permanently covering most of the land mass. The seismic data was acquired by a team of six people during a two-month long experiment in summer of 2011 on the ice cap in the interior of central-eastern Greenland. The EW-trending profile extends 310 km inland from the approximate edge of the stable ice cap near Scoresby Sund across the centre of the ice cap. The planned extension of the profile by use of OBSs and air gun shooting in Scoresbysund Fjord to the east coast of Greenland was unfortunately cancelled, because navigation was prevented by ice drift. 350 Reftek Texan receivers recorded high-quality seismic data from 8 equidistant shots along the profile. Explosive charge sizes were 1 ton at the ends and ca. 500 kg along the profile, loaded with about 100 kg at 35-85 m depth in individual boreholes. Two-dimensional velocity model based on forward ray tracing and tomography modelling shows a decrease of crustal thickness from 47 km below the centre of Greenland in the western part to 40 km in the eastern part of the profile. Earlier studies show that crustal thickness further decreases eastward to ca. 30 km below the fjord system, but details of the changes are unknown. Relatively high lower crustal velocities (Vp 6.8 - 7.3) in the western part of the TopoGreenland profile may indicate past collision tectonics or may be related or to the passage of the Iceland mantle plume. The origin of the pronounced circum-Atlantic mountain ranges in Norway and eastern Greenland, which have

  14. Edaphic Selection Pressures as Drivers of Contrasting White Spruce Ectomycorrhizal Fungal Community Structure and Diversity in the Canadian Boreal Forest of Abitibi-Témiscamingue Region

    PubMed Central

    Nadeau, Martin B.; P. Khasa, Damase

    2016-01-01

    Little is known about edaphic selection pressures as drivers of contrasting white spruce ectomycorrhizal fungal community structure and diversity in the Canadian boreal forest. We hypothesized that community composition differs among the four sites sampled–nursery, mining site, forest edge, and natural forest. Ectomycorrhizal (ECM) fungal community structure and diversity was studied at the four locations with soil fertility gradient through morpho-molecular and phylogenetic analyses in relationships with rhizospheric soil chemical properties. 41 different species were identified. Mining site had a significantly different species composition than the surrounding environments. Soil pH and percentage of roots colonized by ECM fungi increased while soil P, N, Fe, C, K, Mg, Al, Ca, and Na contents declined across the soil fertility gradient: nursery → natural forest → forest edge → mining site. Contrary to the preference of acid soils by ECM fungi, a few ecologically adapted to high pH, poor soil chemical fertility, and low organic matter content colonize white spruce roots on the non-acidogenic mining site, allowing natural regeneration of white spruce seedlings. Other ECM fungi are adapted to high fertigation level of commercial nursery. This study clearly shows the contrasting difference in white spruce ectomycorrhizal fungal community structure and diversity driven by edaphic selection pressures. PMID:27835688

  15. Edaphic Selection Pressures as Drivers of Contrasting White Spruce Ectomycorrhizal Fungal Community Structure and Diversity in the Canadian Boreal Forest of Abitibi-Témiscamingue Region.

    PubMed

    Nadeau, Martin B; P Khasa, Damase

    2016-01-01

    Little is known about edaphic selection pressures as drivers of contrasting white spruce ectomycorrhizal fungal community structure and diversity in the Canadian boreal forest. We hypothesized that community composition differs among the four sites sampled-nursery, mining site, forest edge, and natural forest. Ectomycorrhizal (ECM) fungal community structure and diversity was studied at the four locations with soil fertility gradient through morpho-molecular and phylogenetic analyses in relationships with rhizospheric soil chemical properties. 41 different species were identified. Mining site had a significantly different species composition than the surrounding environments. Soil pH and percentage of roots colonized by ECM fungi increased while soil P, N, Fe, C, K, Mg, Al, Ca, and Na contents declined across the soil fertility gradient: nursery → natural forest → forest edge → mining site. Contrary to the preference of acid soils by ECM fungi, a few ecologically adapted to high pH, poor soil chemical fertility, and low organic matter content colonize white spruce roots on the non-acidogenic mining site, allowing natural regeneration of white spruce seedlings. Other ECM fungi are adapted to high fertigation level of commercial nursery. This study clearly shows the contrasting difference in white spruce ectomycorrhizal fungal community structure and diversity driven by edaphic selection pressures.

  16. Integrated permanent plot and aerial monitoring for the spruce budworm decision support system

    Treesearch

    David A. MacLean

    2000-01-01

    Spruce budworm (Choristoneura fumiferana Clem.) outbreaks cause severe mortality and growth loss of spruce and fir forest over ranch of eastern North America. The Spruce Budworm Decision Support System (DSS) links prediction and interpretation models to the ARC/1NFO GIS, under an ArcView graphical user interface. It helps forest managers predict...

  17. Geologic and structural map of eastern Asia

    SciTech Connect

    Letouzey, J.; Sage, L.

    1986-07-01

    A synthesis of the onshore and offshore geologic data of eastern Asia, prepared by the Institut Francais du Petrole (IFP), has allowed the construction of geologic and structural maps for this region. These maps include three color sheets (scale = 1:2.5 million) and three plates of geologic and structural cross sections. Located between lat. 4/sup 0/ and 35/sup 0/N, and long. 106/sup 0/ and 132/sup 0/E, the maps cover the following geographic areas: East and South China Sea, Sulu Sea, West Philippine basin and onshore neighboring terrains, Kyushu and Ryukyu Islands, the China margin, Taiwan Island, Vietnam, North West Borneo, and the Philippines. The maps synthesize seismic interpretations, oil well data, geologic work in south Japan, Taiwan, Borneo, and the Philippines, and recent data published between 1976 and 1985. Twenty-four geologic cross sections (scale = 1:1.25 million, vertical exaggeration x 6) intersect ocean margins, important basins, and the different structural domains. They are based on seismic profiles, well data, and available onshore and offshore geologic data. These cross sections show basement composition and structures, different tectonic and sedimentary domains, and the structure and thickness of different sedimentary deposits (such as age, unconformities, and geologic structures). Maps and cross sections will be published in early 1987.

  18. Comparison of Bt formulations against the spruce budworm

    Treesearch

    Lew McCreery; Imants Millers; Dennis Souto; Bruce Francis

    1985-01-01

    The Passamaquoddy Indian Forestry Department treated 40,300 acres in Maine in 1983 using Bt to protect red spruce and eastern hemlock from spruce budworm damage. The post treatment evaluation indicated that the protection objectives were achieved. In cooperation between the Passamaquoddy Indian Forestry Department and two commercial Bt suppliers, Abbott Laboratories...

  19. Species composition and stand structure of a large red spruce planting 67 years after its establishment in western North Carolina

    Treesearch

    W. Henry McNab; James H. Holbrook; Ted M. Oprean

    2010-01-01

    Red spruce (Picea rubens Michx.) is a large and long-lived species that dominated high-elevation forests of the southern Appalachians before most stands were heavily logged in the early 1900s. Restoration of spruce forests by artificial methods has been studied since the 1920s, but little information is available on characteristics of older planted...

  20. Spruce aphid, Elatobium abietinum (Walker): Life history and damage to Engelmann spruce in the Pinaleno Mountains, Arizona

    Treesearch

    Ann M. Lynch

    2009-01-01

    Spruce aphid is an exotic insect recently introduced to the Pinaleno Mountains. It feeds on dormant Engelmann spruce, and possible effects include tree-growth suppression, tree mortality, and reduction in seed and cone production. Potential longer-term effects include changes in forest structure and species composition - primarily through reduction in Engelmann spruce...

  1. Norway spruce embryogenesis: changes in carbohydrate profile, structural development and response to polyethylene glycol

    PubMed Central

    Hudec, Lukáš; Konrádová, Hana; Hašková, Anna; Lipavská, Helena

    2016-01-01

    Two unrelated, geographically distinct, highly embryogenic lines of Norway spruce (Picea abies (L.) Karst.) were analysed to identify metabolic traits characteristic for lines with good yields of high-quality embryos. The results were compared with corresponding characteristics of a poorly productive line (low embryo yield, scarce high-quality embryos). The following carbohydrate profiles and spectra during maturation, desiccation and germination were identified as promising characteristics for line evaluation: a gradual decrease in total soluble carbohydrates with an increasing sucrose : hexose ratio during maturation; accumulation of raffinose family oligosaccharides resulting from desiccation and their rapid degradation at the start of germination; and a decrease in sucrose, increase in hexoses and the appearance of pinitol with proceeding germination. We propose that any deviation from this profile in an embryonic line is a symptom of inferior somatic embryo development. We further propose that a fatty acid spectrum dominated by linoleic acid (18 : 2) was a common feature of healthy spruce somatic embryos, although it was quite different from zygotic embryos mainly containing oleic acid (18 : 1). The responses of the lines to osmotic stress were evaluated based on comparison of control (without osmoticum) and polyethylene glycol (PEG)-exposed (PEG 4000) variants. Although genetically distinct, both highly embryogenic lines responded in a very similar manner, with the only difference being sensitivity to high concentrations of PEG. At an optimum PEG concentration (3.75 and 5%), which was line specific, negative effects of PEG on embryo germination were compensated for by a higher maturation efficiency so that the application of PEG at an appropriate concentration improved the yield of healthy germinants per gram of initial embryonal mass and accelerated the process. Polyethylene glycol application, however, resulted in no improvement of the poorly

  2. Concentrations of Ca and Mg in early stages of sapwood decay in red spruce, eastern hemlock, red maple, and paper birch

    Treesearch

    Kevin T. Smith; Walter C. Shortle; Jody Jellison; Jon Connolly; Jonathan Schilling

    2007-01-01

    The decay of coarse woody debris is a key component in the formation of forest soil and in the biogeochemical cycles of Ca and Mg. We tracked changes in density and concentration of Ca and Mg in sapwood of red maple (Acer rubrum L.), red spruce (Picea rubens Sarg.), paper birch (Betula papyrifera Marsh.), and...

  3. Upper mantle anisotropy structure beneath eastern Tibet

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Wang, W.; Wen, L.; Chen, X.

    2013-12-01

    Continental collision between the Indian and the Eurasian plates resulted in uplift of the Tibetan plateau and the thickening of the crust. A lot of work has been done on the crust structures beneath Tibet, and several tectonic models are proposed to explain the mechanism of the uplift and thickening. But due to the absence of the upper mantle structures, those models are still under debate. Fine upper mantle velocity and anisotropy structures can help us understand the dynamic process of the Tibetan plateau. Previous studies used shear wave splitting and surface wave analysis to study anisotropy structures beneath the Tibetan plateau. But those two methods provide a poor vertical resolution in upper mantle. Waveform modeling of upper mantle triplication phases can provide a good vertical resolution, but present methods for calculating synthetic seismograms cannot process anisotropic media. We develop a method based on the generalized reflection and transmission method (GRTM) to calculate synthetic seismograms for wave propagating in stratified VTI media, so we can waveform model upper mantle triplications propagating in anisotropic media. Recently, the increasing number of permanent and temporary seismic stations near Tibet provides us a good opportunity to study fine upper mantle structures beneath the Tibetan plateau. In this study, we waveform model the tangential and radial seismic triplication data recorded in Chinese digital seismic stations at a epicentral distance of 10-30 degree for several events occurring in middle Tibet to constrain fine upper mantle velocity and anisotropy structures beneath eastern Tibet. We also use mineral physics modeling method to explore thermal and compositional models that would explain the inferred seismic structures.

  4. High Resolution Velocity Structure in Eastern Turkey

    SciTech Connect

    Pasyanos, M; Gok, R; Zor, E; Walter, W

    2004-09-03

    We investigate the crustal and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet and form a complex tectonic structure. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provided a unique opportunity for studying the high resolution velocity structure. Zor et al. found an average 46 km thick crust in Anatolian plateau using six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver function alone with many-layered parameterization may result in an apparent depth-velocity tradeoff. In order to improve previous velocity model, we employed the joint inversion method with many layered parameterization of Julia et al. (2000) to the ETSE receiver functions. In this technique, the receiver function and surface-wave observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. We consider azimuthal changes of receiver functions and have stacked them into different groups. We calculated the receiver functions using iterative time-domain deconvolution technique and surface wave group velocity dispersion curves between 10-100 sec. We are making surface wave dispersion measurements at the ETSE stations and have incorporated them into a regional group velocity model. Preliminary results indicate a strong trend in the long period group velocity in the northeast. This indicates slow upper mantle velocities in the region consistent with Pn, Sn and receiver function results. We started with both the 1-D model that is obtained with the 12 tones dam explosion shot data recorded by ETSE network and the existing receiver function

  5. High Resolution Velocity Structure in Eastern Turkey

    NASA Astrophysics Data System (ADS)

    Pasyanos, M. E.; Gok, R.; Zor, E.; Walter, W. R.

    2004-12-01

    We investigate the crust and upper mantle structure of eastern Turkey where the Anatolian, Arabian and Eurasian Plates meet, forming a complex tectonic regime. The Bitlis suture is a continental collision zone between the Anatolian plateau and the Arabian plate. Broadband data available through the Eastern Turkey Seismic Experiment (ETSE) provide a unique opportunity for studying the high resolution velocity structure of the region. Zor et al. (2003) found an average 46 km thick crust in the Anatolian plateau using a six-layered grid search inversion of the ETSE receiver functions. Receiver functions are sensitive to the velocity contrast of interfaces and the relative travel time of converted and reverberated waves between those interfaces. The interpretation of receiver functions alone, however, may result in an apparent depth-velocity trade-off [Ammon et al., 1990]. In order to improve upon this velocity model, we have combined the receiver functions with surface wave data using the joint inversion method of Julia et al. (2000). In this technique, the two sets of observations are combined into a single algebraic equation and each data set is weighted by an estimate of the uncertainty in the observations. The receiver functions are calculated using an iterative time-domain deconvolution technique. We also consider azimuthal changes in the receiver functions and have stacked them into different groups accordingly. We are improving our surface wave model by making Love and Rayleigh dispersion measurements at the ETSE stations and incorporating them into a regional group velocity model for periods between 10 and 100 seconds. Preliminary results indicate a strong trend in the long period group velocities toward the northeast, indicating slow upper mantle velocities in the area consistent with Pn, Sn and receiver function results. Starting models used for the joint inversions include both a 1-D model from a 12-ton dam shot recorded by ETSE [Gurbuz et al., 2004] and

  6. Occurrence of Cystosporogenes sp. (Protozoa, Microsporidia) in a multi-species insect production facility and its elimination from a colony of the eastern spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae).

    PubMed

    van Frankenhuyzen, Kees; Ebling, Peter; McCron, Bob; Ladd, Tim; Gauthier, Debbie; Vossbrinck, Charles

    2004-09-01

    We have isolated a microsporidium from a laboratory colony of the eastern spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae). Light and electron microscopic investigations showed that gross pathology and ultrastructure of our isolate are similar to those described for Cystosporogenes legeri from the European grape vine moth, Lobesia botrana. Comparative phylogenetic analysis of the small subunit rDNA using maximum likelihood, maximum parsimony, and neighbour joining distance methods revealed perfect homology with the C. legeri sequence. The microsporidian was infectious to other Choristoneura species, as well as Malacosoma disstria, Lymantria dispar, and Lambdina fiscellaria. Incubation of infected egg masses at 41 degrees C for 20 min followed by 30 min in 33% formaldehyde did not reduce disease incidence in larval offspring. Exposure of one or two generations to fumagillin at 6000 ppm or higher eliminated infection in adult moths, but also reduced colony fitness. A clean colony was established by conducting individual matings and selecting disease-free offspring.

  7. Hydraulic and mechanical properties of young Norway spruce clones related to growth and wood structure

    PubMed Central

    ROSNER, SABINE; KLEIN, ANDREA; MÜLLER, ULRICH; KARLSSON, BO

    2011-01-01

    Summary Stem segments of eight five-year-old Norway spruce (Picea abies (L.) Karst.) clones differing in growth characteristics were tested for maximum specific hydraulic conductivity (ks100), vulnerability to cavitation and behavior under mechanical stress. The vulnerability of the clones to cavitation was assessed by measuring the applied air pressure required to cause 12 and 50% loss of conductivity (Ψ12, Ψ50) and the percent loss of conductivity at 4 MPa applied air pressure (PLC4MPa). The bending strength and stiffness and the axial compression strength and stiffness of the same stem segments were measured to characterize wood mechanical properties. Growth ring width, wood density, latewood percentage, lumen diameter, cell wall thickness, tracheid length and pit dimensions of earlywood cells, spiral grain and microfibril angles were examined to identify structure–function relationships. High ks100 was strongly and positively related to spiral grain angle, which corresponded positively to tracheid length and pit dimensions. Spiral grain may reduce flow resistance of the bordered pits of the first earlywood tracheids, which are characterized by rounded tips and an equal distribution of pits along the entire length. Wood density was unrelated to hydraulic vulnerability parameters. Traits associated with higher hydraulic vulnerability were long tracheids, high latewood percentage and thick earlywood cell walls. The positive relationship between earlywood cell wall thickness and vulnerability to cavitation suggest that air seeding through the margo of bordered pits may occur in earlywood. There was a positive phenotypic and genotypic relationship between ks100 and PLC4MPa, and both parameters were positively related to tree growth rate. Variability in mechanical properties depended mostly on wood density, but also on the amount of compression wood. Accordingly, hydraulic conductivity and mechanical strength or stiffness showed no tradeoff. PMID:17472942

  8. Specific impacts of beech and Norway spruce on the structure and diversity of the rhizosphere and soil microbial communities

    PubMed Central

    Uroz, S.; Oger, P.; Tisserand, E.; Cébron, A.; Turpault, M.-P.; Buée, M.; De Boer, W.; Leveau, J. H. J.; Frey-Klett, P.

    2016-01-01

    The impacts of plant species on the microbial communities and physico-chemical characteristics of soil are well documented for many herbs, grasses and legumes but much less so for tree species. Here, we investigate by rRNA and ITS amplicon sequencing the diversity of microorganisms from the three domains of life (Archaea, Bacteria and Eukaryota:Fungi) in soil samples taken from the forest experimental site of Breuil-Chenue (France). We discovered significant differences in the abundance, composition and structure of the microbial communities associated with two phylogenetically distant tree species of the same age, deciduous European beech (Fagus sylvatica) and coniferous Norway spruce (Picea abies Karst), planted in the same soil. Our results suggest a significant effect of tree species on soil microbiota though in different ways for each of the three microbial groups. Fungal and archaeal community structures and compositions are mainly determined according to tree species, whereas bacterial communities differ to a great degree between rhizosphere and bulk soils, regardless of the tree species. These results were confirmed by quantitative PCR, which revealed significant enrichment of specific bacterial genera, such as Burkholderia and Collimonas, known for their ability to weather minerals within the tree root vicinity. PMID:27302652

  9. Red spruce dynamics in an old southern Appalachian forest

    USGS Publications Warehouse

    Busing, R.T.

    2004-01-01

    By the late 1980s the composition and structure of forest stands in the southern Appalachian spruce-fir zone were altered by insect infestations to Fraser fir. The response of red spruce, the sole remaining coniferous forest dominant, to this disturbance was followed over twenty years (1983-2003) in an old spruce-fir forest at Mt. Collins, Great Smoky Mountains National Park. Although diameter growth of canopy red spruce (>30 cm dbh) at six plot sites was considerable (mean 10-yr increment 2.1 cm; 1993-2003), red spruce mortality increased sharply (mean 4% yr-1; 1993-2003). Wind-related mortality of canopy red spruce was substantial after the loss of Fraser fir from the canopy circa 1985 (>70% of the dead spruce had broken or uprooted boles; 1983-2003). Wind damage to red spruce was observed at most plot sites, but it was most pronounced on exposed topographic positions, where canopy gap expansion was extensive. The elevated mortality of red spruce at Mt. Collins was not associated with reduced diameter growth. Altered canopy structure has left large red spruce vulnerable to high winds. With the loss of canopy fir and the subsequent increase in mortality of canopy spruce, total live basal area has declined to about half of its pre-disturbance level.

  10. Eastern Boundary Effects on General Circulation Structure

    NASA Technical Reports Server (NTRS)

    Dewar, William K.

    1997-01-01

    My NASA proposal included plans to examine the dynamics of the eastern oceanic boundary, with a view towards those processes important to the interior. Several relevant tasks have been completed and either have appeared or will appear soon in the refereed literature.

  11. A high-resolution reference genetic map positioning 8.8 K genes for the conifer white spruce: structural genomics implications and correspondence with physical distance.

    PubMed

    Pavy, Nathalie; Lamothe, Manuel; Pelgas, Betty; Gagnon, France; Birol, Inanç; Bohlmann, Joerg; Mackay, John; Isabel, Nathalie; Bousquet, Jean

    2017-04-01

    Over the last decade, extensive genetic and genomic resources have been developed for the conifer white spruce (Picea glauca, Pinaceae), which has one of the largest plant genomes (20 Gbp). Draft genome sequences of white spruce and other conifers have recently been produced, but dense genetic maps are needed to comprehend genome macrostructure, delineate regions involved in quantitative traits, complement functional genomic investigations, and assist the assembly of fragmented genomic sequences. A greatly expanded P. glauca composite linkage map was generated from a set of 1976 full-sib progeny, with the positioning of 8793 expressed genes. Regions with significant low or high gene density were identified. Gene family members tended to be mapped on the same chromosomes, with tandemly arrayed genes significantly biased towards specific functional classes. The map was integrated with transcriptome data surveyed across eight tissues. In total, 69 clusters of co-expressed and co-localising genes were identified. A high level of synteny was found with pine genetic maps, which should facilitate the transfer of structural information in the Pinaceae. Although the current white spruce genome sequence remains highly fragmented, dozens of scaffolds encompassing more than one mapped gene were identified. From these, the relationship between genetic and physical distances was examined and the genome-wide recombination rate was found to be much smaller than most estimates reported for angiosperm genomes. This gene linkage map shall assist the large-scale assembly of the next-generation white spruce genome sequence and provide a reference resource for the conifer genomics community.

  12. Identifying the pollen of an extinct spruce species in the Late Quaternary sediments of the Tunica Hills region, south-eastern United States

    USGS Publications Warehouse

    Luke Mander,; Jacklyn Rodriguez,; Pietra G. Mueller,; Jackson, Stephen T.; Surangi W. Punyasena,

    2014-01-01

    Late Quaternary fluvial deposits in the Tunica Hills region of Louisiana and Mississippi are rich in spruce macrofossils of the extinct species Picea critchfieldii, the one recognized plant extinction of the Late Quaternary. However, the morphology of P. critchfieldii pollen is unknown, presenting a barrier to the interpretation of pollen spectra from the last glacial of North America. To address this issue, we undertook a morphometric study of Picea pollen from Tunica Hills. Morphometric data, together with qualitative observations of pollen morphology using Apotome fluorescence microscopy, indicate that Picea pollen from Tunica Hills is morphologically distinct from the pollen of P. glauca, P. mariana and P. rubens. Measurements of grain length, corpus width and corpus height indicate that Picea pollen from Tunica Hills is larger than the pollen of P. mariana and P. rubens, and is slightly larger than P. glauca pollen. We argue that the morphologically distinctive Tunica Hills Picea pollen was probably produced by the extinct spruce species P. critchfieldii. These morphological differences could be used to identify P. critchfieldii in existing and newly collected pollen records, which would refine its paleoecologic and biogeographic history and clarify the nature and timing of its extinction in the Late Quaternary.

  13. Legacy of Pre-Disturbance Spatial Pattern Determines Early Structural Diversity following Severe Disturbance in Montane Spruce Forests

    PubMed Central

    Bače, Radek; Svoboda, Miroslav; Janda, Pavel; Morrissey, Robert C.; Wild, Jan; Clear, Jennifer L.; Čada, Vojtěch; Donato, Daniel C.

    2015-01-01

    Background Severe canopy-removing disturbances are native to many temperate forests and radically alter stand structure, but biotic legacies (surviving elements or patterns) can lend continuity to ecosystem function after such events. Poorly understood is the degree to which the structural complexity of an old-growth forest carries over to the next stand. We asked how pre-disturbance spatial pattern acts as a legacy to influence post-disturbance stand structure, and how this legacy influences the structural diversity within the early-seral stand. Methods Two stem-mapped one-hectare forest plots in the Czech Republic experienced a severe bark beetle outbreak, thus providing before-and-after data on spatial patterns in live and dead trees, crown projections, down logs, and herb cover. Results Post-disturbance stands were dominated by an advanced regeneration layer present before the disturbance. Both major species, Norway spruce (Picea abies) and rowan (Sorbus aucuparia), were strongly self-aggregated and also clustered to former canopy trees, pre-disturbance snags, stumps and logs, suggesting positive overstory to understory neighbourhood effects. Thus, although the disturbance dramatically reduced the stand’s height profile with ~100% mortality of the canopy layer, the spatial structure of post-disturbance stands still closely reflected the pre-disturbance structure. The former upper tree layer influenced advanced regeneration through microsite and light limitation. Under formerly dense canopies, regeneration density was high but relatively homogeneous in height; while in former small gaps with greater herb cover, regeneration density was lower but with greater heterogeneity in heights. Conclusion These findings suggest that pre-disturbance spatial patterns of forests can persist through severe canopy-removing disturbance, and determine the spatial structure of the succeeding stand. Such patterns constitute a subtle but key legacy effect, promoting structural

  14. Structure and dynamics in a virgin northern hardwood-spruce-fir forest--the Bowl, New Hampshire

    Treesearch

    Stanley R. Gemborys

    1996-01-01

    A phytosociological study was conducted in a virgin northern hardwood- spruce-fir forest in the Bowl in the White Mountains of New Hampshire. There is no evidence of fire or human disturbance but hurricane winds were significant in the past. Bray and Curtis ordination was used to develop an XY vegetational mosaic. Differentiating species were Picea rubens and Acer...

  15. Crown structure and growth efficiency of red spruce in uneven-aged, mixed-species stands in Maine

    Treesearch

    Douglas A. Maguire; John C. Brissette; Lianhong. Gu

    1998-01-01

    Several hypotheses about the relationships among individual tree growth, tree leaf area, and relative tree size or position were tested with red spruce (Picea rubens Sarg.) growing in uneven-aged, mixed-species forests of south-central Maine, U.S.A. Based on data from 65 sample trees, predictive models were developed to (i)...

  16. Genetic diversity, genetic structure, and mating system of brewer spruce (Pinaceae), a relict of the acto-tertiary forest

    Treesearch

    F. Thomas Ledig; Paul D. Hodgskiss; David R. Johnson

    2005-01-01

    Brewer spruce (Picea breweriana), a relict of the widespread Arcto-Tertiary forests, is now restricted to a highly fragmented range in the Klamath Region of California and Oregon. Expected heterozygosity for 26 isozyme loci, averaged over 10 populations, was 0.121. More notable than the relatively high level of diversity when compared to other woody...

  17. Ambient seismic noise tomography and structure of eastern North America

    NASA Astrophysics Data System (ADS)

    Liang, Chuntao; Langston, Charles A.

    2008-03-01

    The time derivative of cross-correlation functions (CCF) of ambient noise fields recorded by two stations can be approximated as the Green's Function (GF) between the stations. The CCFs are thus used as Peudo-GFs (dominated by surface waves) to invert for group velocity structure in eastern North America. Stations from two regional networks deployed to monitor the New Madrid Seismic Zone and eastern Tennessee seismic zone, together with stations of the US National Seismic Network, greatly improve tomographic ray coverage. The short period (T = 5 s) group velocity map shows strong correlations with the depth to Precambrian basement. Many subtle local structures can be clearly identified from the velocity map, including the Ozark uplift, Cincinnati Arch, Nashville Dome and the Blue Ridge province of the Appalachians showing relatively high group velocity. The long period (T = 15 s) group velocity map shows strong correlations with regional geology. Ancient rift basins, such as the Mid-Continent Rift (MCR) system, the Reelfoot rift, the Oklahoma Aulacogen and the Eastern Continent Rift, are associated with low velocity belts along their rift axes. We also find that all major seismic zones in eastern North America, such as the New Madrid seismic zone, Eastern Tennessee seismic zone as well as Ouachita Orogen seismic zone, are approximately located at transition zones separating velocity highs and lows. This observation suggests that those seismic zones may reflect the reactivation of ancient faults associated with continental rift and collision zones.

  18. Structural characteristics of water-soluble polysaccharides from Norway spruce (Picea abies).

    PubMed

    Shakhmatov, Evgeny G; Belyy, Vladimir A; Makarova, Elena N

    2017-11-01

    Arabinogalactan proteins and pectic polysaccharides were isolated from greenery of Picea abies by water extraction. Main elements of their structure were determined by ion-exchange chromatography, partial acid and enzymatic hydrolysis, and NMR spectroscopy. It was established that the backbone of pectin macromolecules of greenery of P. abies is represented by segments of partially methyl-esterified and acetylated 1,4-α-d-galactopyranosyluronan, and partially 2-O- and/or 3-O-acetylated RG-I with side chains consisting of highly-branched 1,5-α-l-arabinan segments. The carbohydrate part of AGP of greenery of P. abies consists of AG-II, the main chain of which is represented by 1,3-β-d-Galp and 1,3,6-β-d-Galp residues. The side chains of AG-II are formed of 1,6- and 1,3,6-β-d-Galp, 1,3- and 1,5-α-l-Araf, β-d-GlcpA and 1,4-β-d-GlcpA, T-α-l-Araf, T-α-l-Rhap and T-α-l-Fucp residues. The AGPs of P. abies are also characterized by the presence of an unusual 4-O-Me-α-l-Fucp monosaccharide, which, as far as we know, was not found in pectins or AGP earlier. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Cold tolerance and photosystem function in a montane red spruce population: physiological relationships with foliar carbohydrates

    Treesearch

    P.G. Schaberg; G.R. Strimbeck; G.J. Hawley; D.H. DeHayes; J.B. Shane; P.F. Murakami; T.D. Perkins; J.R. Donnelly; B.L. Wong

    2000-01-01

    Red spruce (Picea rubens Sarg.) growing in northern montane forests of eastern North America appears to be distinctive with respect to at least two aspects of winter physiology. First, red spruce attains only a modest level of midwinter cold tolerance compared to other north temperate conifers and appears barely capable of avoiding freezing injury at...

  20. Genetic structure of Sakhalin spruce (Picea glehnii) in northern Japan and adjacent regions revealed by nuclear microsatellites and mitochondrial gene sequences.

    PubMed

    Aizawa, Mineaki; Yoshimaru, Hiroshi; Takahashi, Makoto; Kawahara, Takayuki; Sugita, Hisashi; Saito, Hideyuki; Sabirov, Renat N

    2015-01-01

    The genetic structure of Sakhalin spruce (Picea glehnii) was studied across the natural range of the species, including two small isolated populations in south Sakhalin and Hayachine, by using six microsatellite loci and maternally inherited mitochondrial gene sequences. We also analyzed P. jezoensis, a sympatric spruce in the range. Genetic diversity of P. glehnii was higher in central Hokkaido and the lowest in the Hayachine. Bayesian clustering and principal coordinate analysis by using the microsatellites indicated that the Hayachine was clearly distinct from other populations, implying that it had undergone strong genetic drift since the last glacial period. P. glehnii harbored four mitochondrial haplotypes, two of which were shared with P. jezoensis. One of the two was observed without geographical concentration, suggesting its derivation from ancestral polymorphism. Another was observed in south Sakhalin and in P. jezoensis across Sakhalin. The Bayesian clustering--by using four microsatellite loci, including P. jezoensis populations--indicated unambiguous species delimitation, but with possible admixture of P. jezoensis genes into P. glehnii in south Sakhalin, where P. glehnii is abundantly overwhelmed by P. jezoensis; this might explain the occurrence of introgression of the haplotype of P. jezoensis into P. glehnii.

  1. Relationships among the spruces (Picea, Pinaceae) of southwestern North America

    Treesearch

    F. Thomas Ledig; Paul D. Hodgskiss; Konstanin V. Krutovskii; David B. Neale; Teobaldo Eguiluz-Piedra

    2004-01-01

    Numerous populations from six spruce taxa, including four relict endemics, Picea chihuahuana (Chihuahua spruce), P. martinezii (Martínez spruce), P. mexicana (Mexican spruce), and P. breweriana (Brewer spruce), and two widespread species, P. engelmannii (Engelmann spruce) and...

  2. Eddy covariance fluxes of the NO-NO2-O3 triad above a spruce forest canopy in south-eastern Germany.

    NASA Astrophysics Data System (ADS)

    Tsokankunku, A.; Zhu, Z.; Meixner, F. X.; Foken, T.; Andreae, M. O.

    2009-04-01

    We investigated the diel variability of the eddy covariance fluxes of the NO-NO2-O3 triad above a spruce forest canopy at the "Weidenbrunnen" research site (Fichtelgebirge, Germany). Measurements were part of the EGER project (ExchanGE processes in mountainous Regions), which focuses on the role of process interactions among the different scales of soil, in-canopy and atmospheric exchange processes of reactive and non-reactive trace gases and energy. The eddy covariance platform was at the top of a 32 m high tower (50˚ 08'31" N, 11˚ 52'1"E, elevation 755 m.a.s.l). The eddy covariance system consisted of a CSAT3 sonic anemometer and a high speed, high resolution NO-NO2two channel chemiluminescence analyzer (Ecophysics CLD 790 SR2). A solid-state blue-light photolytic converter was connected to the NO2 channel of the analyzer just behind the sample inlet. Ambient NO and NO2 mixing ratios were sampled via 52 m long tubes with the instrument itself located in a temperature-controlled container at the ground. The NO-NO2 analyzer was operated at 5 Hz. Additionally we measured eddy covariance fluxes of CO2 and H2O. An infrared absorption-based analyzer (LI-7000) was used to sample CO2 and H2O mixing ratios, and a fast solid-phase chemiluminescence ozone analyzer (GFAS) was deployed to measure O3 mixing ratios. All trace gas inlets were situated at 32.5 m, 20 cm below the path of the sonic anemometer. The 32m inlet of an independent NO, NO2, and O3 concentration profile measuring system was used as the calibration source for the fast ozone analyzer and the two channel NO-NO2chemiluminescence analyzer. Preliminary results show that NO and NO2advection plays a big role in the magnitude and direction of the fluxes at the site. The main source of the advection is a busy country road situated about 2 km west of the site. CO2 fluxes were also influenced by advection. Extended periods of stationarity usually occurred on Sundays when the amount of traffic was significantly

  3. Spruce budworm returns to Northeast

    Treesearch

    Lloyd Irland; William H. McWilliams

    2014-01-01

    Thinking of the Northern Forest brings to mind spruce/fir (S/F) forests, cool climates, and high elevations: not to mention fishing and canoe trips: however, spruce and fir are also very important to the northern timber economy and rural development. Considering new concerns over the spruce budworm, an update on the status of this critically important forest resource...

  4. Structural changes in the vascular bundles of light-exposed and shaded spruce needles suffering from Mg deficiency and ozone pollution.

    PubMed

    Boxler-Baldoma, Carmen; Lütz, Cornelius; Heumann, Hans-Günther; Siefermann-Harms, Dorothea

    2006-02-01

    The correlation between structural changes of the vascular bundles and needle yellowing was examined for needles of damaged spruce (Picea abies (L.) Karst.) growing at a Mg-deficient and ozone polluted mountain site in the Central Black Forest (840m a.s.l.). In the previous year's sun-exposed needles, the following sequence of events was observed: (1) rapid needle yellowing, (2) hypertrophy and anomalous divisions of cambium cells, (3) phloem collapse, and, (4) production of atypical xylem tracheids. Under defined shade (reduction of the photosynthetically active photon flux density of the ambient light by 85-90%), the needles remained green, while the phloem collapsed completely within the first 6 weeks of shading; subsequently, a reversal of the collapse was observed. Under both light conditions, the content of Mg not bound to chlorophyll (Mg(free)) was in the range of 0.1 mg g(-1) needle dry matter, and hardly changed throughout the investigation period. After Mg fertilization, the Mg(free) level of the previous year's needles increased to 0.2 mg g(-1) dry matter, the light-exposed needles remained green, and the vascular bundles developed no anomalies. The data show that the rapid needle yellowing of ozone-exposed Mg-deficient needles did not depend on the collapse of the phloem. Mg deficiency played a key role in the development of anomalous vascular bundles under light, and also appears to explain the transient changes in sieve cell structure under shade. The role of Mg deficiency, rather than ozone pollution, in the damage of the sieve cells was confirmed in a long-term ozone exposure experiment with young clonal spruce growing under defined conditions.

  5. New interpretation of the deep mantle structure beneath eastern China

    NASA Astrophysics Data System (ADS)

    Ma, Pengfei; Liu, Shaofeng; Lin, Chengfa; Yao, Xiang

    2016-04-01

    Recent study of high resolution seismic tomography presents a large mass of high velocity abnormality beneath eastern China near the phase change depth, expanding more than 1600km-wide in East-west cross-section across the North China plate. This structure high is generally believed to be the subducted slab of Pacific plate beneath the Eurasia continent, while its origin and dynamic effect on the Cenozoic tectonic evolution of eastern China remain to be controversial. We developed a subduction-driven geodynamic mantle convection model that honors a set of global plate reconstruction data since 230Ma to help understand the formation and evolution of mantle structure beneath eastern China. The assimilation of plate kinematics, continuous evolving plate margin, asymmetric subduction zone, and paleo seafloor age data enables the spatial and temporal consistency between the geologic data and the mantle convection model, and guarantees the conservation of the buoyancy flux across the lithosphere and subducted slabs. Our model achieved a first order approximation between predictions and the observed data. Interestingly, the model suggests that the slab material stagnated above discontinuity didn't form until 15Ma, much later than previous expected, and the fast abnormality in the mid-mantle further west in the tomographic image is interpreted to be the remnants of the Mesozoic Izanagi subduction. Moreover, detailed analysis suggests that the accelerated subduction of Philippine Sea plate beneath Eurasia plate along the Ryukyu Trench and Nankai Trough since 15Ma may largely contribute to extending feature above 670km discontinuity. The long distance expansion of the slab material in the East-west direction may be an illusion caused by the approximate spatial perpendicularity between the cross-section and the subduction direction of the Philippine Sea plate. Our model emphasizes the necessity of the re-examination on the geophysical observation and its tectonic and

  6. Red spruce as witness tree on the Monongahela National Forest

    Treesearch

    Melissa. Thomas-Van Gundy

    2010-01-01

    A digital database of witness tree locations has been created from the earliest deeds of the area now within the Monongahela National Forest. These locations were used to describe the distribution, environmental gradients, and associated tree species of red spruce (Picea rubens) in eastern West Virginia from between 1771 and 1889.

  7. Erynia radicans as a mycoinsecticide for spruce budworm control

    Treesearch

    Richard S. Soper

    1985-01-01

    The entomopahtogenic fungus Erynia radicans, has been under investigation for several years as a possible alternative to chemical control of the eastern spruce budworm. A commercial production method has been developed which allows the formulation of this pathogen as a mycoinsecticide. A standardized bioassay method was used to select strain RS141 as...

  8. Structure, production and resource use in some old-growth spruce/fir forests in the front range of the Rocky Mountains, USA

    USGS Publications Warehouse

    Binkley, Dan; Olsson, U.; Rochelle, R.; Stohlgren, T.; Nikolov, N.

    2003-01-01

    Old-growth forests of Engelmann spruce (Picea engelmannii Parry ex. Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.) dominate much of the landscape of the Rocky Mountains. We characterized the structure, biomass and production of 18 old-growth (200-450-year-old) spruce/fir forests in Rocky Mountain National Park, Colorado, as well as the stand-level supply and use of light and nitrogen. Stands were chosen to span a broad range of elevation, aspect, and topography. Aboveground tree biomass in these old-growth forests averaged 253 Mg/ha (range 130-488 Mg/ha), with aboveground net primary production of 3700 kg ha-1 yr-1 (range from 2700 to 5200 kg ha-1 yr-1). Within stands, trees >35 cm in diameter accounted for 70% of aboveground biomass, but trees <35 cm contributed 70% of the production of woody biomass. Differences in slope and aspect among sites resulted in a range of incoming light from 58 to 74 TJ ha-1 yr-1, and tree canopies intercepted an average of 71% of incoming light (range 50-90%). Aboveground net primary production (ANPP) of trees did not relate to the supply of light or N, but ANPP correlated strongly with the amount of light and N used (r2 = 0.45-0.54, P < 0.01). Uptake of 1 kg of N was associated with about 260 kg of ANPP, and one TJ of intercepted shortwave radiation produced about 78 kg of ANPP. Across these old-growth stands, stands with greater biomass showed higher rates of both ANPP and resource use; variation in aboveground biomass was associated with 24% of the variation in N use (P = 0.04), 44% of the light use (P = 0.003), and 45% of the ANPP (P = 0.002). ?? 2002 Elsevier Science B.V. All rights reserved.

  9. Investigation of upper crustal structure beneath eastern Java

    NASA Astrophysics Data System (ADS)

    Martha, Agustya Adi; Widiyantoro, Sri; Cummnins, Phil; Saygin, Erdinc; Masturyono

    2016-05-01

    The complexity of geology structure in eastern Java causes this region has many potential resources as much as the disasters. Therefore, the East Java province represents an interesting area to be explored, especially regarding its upper crustal structure. To investigate this structure, we employ the Ambient Noise Tomography (ANT) method. We have used seismic waveform data from 25 Meteorological, Climatological and Geophysical Agency (BMKG) stationary seismographic stations and 26 portable seismographs installed for 2 to 8 weeks. Inter-station cross-correlation produces more than 800 Rayleigh wave components, which depict the structure beneath eastern Java. Based on the checkerboard resolution test, we found that the optimal grid size is 0.25ox0.25o. Our inversion results for the periods of 1 to 10 s indicate a good agreement with geological and Bouguer anomaly maps. Rembang high depression, most of the southern mountains zone, the northern part of Rembang zone and the central part of the Madura Island, the area of high gravity anomaly and areas dominated with igneous rocks are associated with high velocity zones. On the other hand, Kendeng zone and most of the basin in the Rembang zone are associated with low velocity zones.

  10. Structural evolution of Halaban Area, Eastern Arabian Shield, Saudi Arabia

    NASA Astrophysics Data System (ADS)

    Al-Amri, Yousef; Kassem1, Osama M. K.

    2017-04-01

    Neoproterozoic basement complex comprises a metamorphic/igneous suite (Abt schist and sheared granitoids) with syn-accretionary transpressive structures, unconformably overlain by a post-amalgamation volcanosedimentary sequence. This study aims to attempt to exposed post-accretionary thrusting and thrust-related structures at Halaban area, Eastern Arabian Shield. The Rf/ϕ and Fry methods are utilized on quartz and feldspar porphyroclasts, as well as on mafic crystals, such as hornblende and biotite, in eighteen samples. The X/Z axial ratios range from 1.12 to 4.99 for Rf/ϕ method and from 1.65 to 4.00 for Fry method. The direction of finite strain for the long axes displays clustering along the WNW trend (occasionally N) with slight plunging. Finite strain accumulated without any significant volume change contemporaneously with syn-accretionary transpressive structures. It indicates that the contacts between various lithological units in the Halaban area were formed under brittle to semi-ductile deformation conditions. The penetrative subhorizontal foliation was concurrent with thrusting and shows nearly the same attitudes of tectonic contacts with the overlying nappes. Keywords: Finite strain analysis, volcanosedimentary sequence, Halaban area, Eastern Arabian Shield, Saudi Arabia.

  11. Upper mantle anisotropy structure beneath eastern Tibet and its exploration

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Wen, L.

    2014-12-01

    Continental collision between the Indian and the Eurasian plates resulted in uplift of the Tibetan plateau and the thickening of the crust. A lot of work has been done on the crust structures beneath Tibet, and several tectonic models are proposed to explain the mechanism of the uplift and thickening. But due to the absence of the upper mantle structures, those models are still under debate. Fine upper mantle velocity and anisotropy structures can help us understand the dynamic process of the Tibetan plateau. Waveform modeling of upper mantle triplication phases can provide a good vertical resolution of upper mantle velocity structures, but present methods for calculating synthetic seismograms cannot process anisotropic media. We develop a method based on the generalized reflection and transmission method (GRTM) to calculate synthetic seismograms for wave propagating in stratified VTI media, so we can waveform model upper mantle triplications propagating in anisotropic media. In this study, we waveform model the tangential and radial seismic triplication data recorded in Chinese digital seismic stations at a epicentral distance of 10-30 degree for one events occurring in middle Tibet to constrain fine upper mantle velocity and anisotropy structures beneath eastern Tibet. The result shows that horizontal S wave velocity is larger than vertical S wave velocity in the upper mantle beneath eastern Tibet. We also build a mineral physics modeling method, which can calculate upper mantle anisotropy structures based on mantle temperatures, compositions and directions of mantle flow, and use this method to explore compositional and dynamic models that would explain the inferred seismic structures. The results suggest that in our sampling region, the water content is lower than 0.4 wt%, and there is vertical mantle flow beneath the lithospheric lid.

  12. Western Spruce Budworm

    Treesearch

    David G. Fellin; Jerald E. Dewey

    1982-01-01

    The western spruce budworm, Choristoneura occidentalis Freeman, is the most widely distributed and destructive defoliator of coniferous forests in Western North America. It is one of nearly a dozen Choristoneura species, subspecies, or forms, with a complexity of variation among populations found throughout much of the United States and Canada. It occurs in the Rocky...

  13. Structure and shale gas production patterns from eastern Kentucky field

    SciTech Connect

    Shumaker, R.C.

    1987-09-01

    Computer-derived subsurface structure, isopach, and gas-flow maps, based on 4000 drillers logs, have been generated for eastern Kentucky under a project sponsored by the Gas Research Institute. Structure maps show low-relief flextures related to basement structure. Some structures have been mapped at the surface, others have not. Highest final open-flow (fof) of shale gas from wells in Martin County follow a structural low between (basement) anticlines. From there, elevated gas flows (fof) extend westward along the Warfield monocline to Floyd County where the high flow (fof) trend extends southward along the Floyd County channel. In Knott County, the number of wells with high gas flow (fof) decreases abruptly. The center of highest gas flow (fof) in Floyd County spreads eastward to Pike County, forming a triangular shaped area of high production (fof). The center of highest gas flow (fof) is in an area where possible (basement) structure trends intersect and where low-relief surface folds (probably detached structure) were mapped and shown on the 1922 version of the Floyd County structure map. Modern regional maps, based on geophysical logs from widely spaced wells, do not define the low-relief structures that have been useful in predicting gas flow trends. Detailed maps based on drillers logs can be misleading unless carefully edited. Comparative analysis of high gas flows (fof) and 10-year cumulative production figures in a small area confirms that there is a relationship between gas flow (fof) values and long-term cumulative production.

  14. Full Genome of Phialocephala scopiformis DAOMC 229536, a Fungal Endophyte of Spruce Producing the Potent Anti-Insectan Compound Rugulosin

    PubMed Central

    Frasz, Samantha L.; Seifert, Keith A.; Miller, J. David; Mondo, Stephen J.; LaButti, Kurt; Lipzen, Anna; Dockter, Rhyan B.; Kennedy, Megan C.; Grigoriev, Igor V.; Spatafora, Joseph W.

    2016-01-01

    We present the full genome of Phialocephala scopiformis DAOMC 229536 (Helotiales, Ascomycota), a foliar endophyte of white spruce from eastern Quebec. DAOMC 229536 produces the anti-insectan compound rugulosin, which inhibits a devastating forestry pest, the spruce budworm. This genome will enable fungal genotyping and host-endophyte evolutionary genomics in inoculated trees. PMID:26950333

  15. Composition of the Spruce Budworm (Choristoneura fumiferana) Midgut Microbiota as Affected by Rearing Conditions.

    PubMed

    Landry, Mathieu; Comeau, André M; Derome, Nicolas; Cusson, Michel; Levesque, Roger C

    2015-01-01

    The eastern spruce budworm (Choristoneura fumiferana) is one of the most destructive forest insect pests in Canada. Little is known about its intestinal microbiota, which could play a role in digestion, immune protection, communication and/or development. The present study was designed to provide a first characterization of the effects of rearing conditions on the taxonomic diversity and structure of the C. fumiferana midgut microbiota, using a culture-independent approach. Three diets and insect sources were examined: larvae from a laboratory colony reared on a synthetic diet and field-collected larvae reared on balsam fir or black spruce foliage. Bacterial DNA from the larval midguts was extracted to amplify and sequence the V6-V8 region of the 16S rRNA gene, using the Roche 454 GS-FLX technology. Our results showed a dominance of Proteobacteria, mainly Pseudomonas spp., in the spruce budworm midgut, irrespective of treatment group. Taxonomic diversity of the midgut microbiota was greater for larvae reared on synthetic diet than for those collected and reared on host plants, a difference that is likely accounted for by several factors. A greater proportion of bacteria from the phylum Bacteroidetes in insects fed artificial diet constituted the main difference between this group and those reared on foliage; within the phylum Proteobacteria, the presence of the genus Bradyrhizobium was also unique to insects reared on artificial diet. Strikingly, a Bray-Curtis analysis showed important differences in microbial diversity among the treatment groups, pointing to the importance of diet and environment in defining the spruce budworm midgut microbiota.

  16. Composition of the Spruce Budworm (Choristoneura fumiferana) Midgut Microbiota as Affected by Rearing Conditions

    PubMed Central

    Landry, Mathieu; Comeau, André M.; Derome, Nicolas; Cusson, Michel; Levesque, Roger C.

    2015-01-01

    The eastern spruce budworm (Choristoneura fumiferana) is one of the most destructive forest insect pests in Canada. Little is known about its intestinal microbiota, which could play a role in digestion, immune protection, communication and/or development. The present study was designed to provide a first characterization of the effects of rearing conditions on the taxonomic diversity and structure of the C. fumiferana midgut microbiota, using a culture-independent approach. Three diets and insect sources were examined: larvae from a laboratory colony reared on a synthetic diet and field-collected larvae reared on balsam fir or black spruce foliage. Bacterial DNA from the larval midguts was extracted to amplify and sequence the V6-V8 region of the 16S rRNA gene, using the Roche 454 GS-FLX technology. Our results showed a dominance of Proteobacteria, mainly Pseudomonas spp., in the spruce budworm midgut, irrespective of treatment group. Taxonomic diversity of the midgut microbiota was greater for larvae reared on synthetic diet than for those collected and reared on host plants, a difference that is likely accounted for by several factors. A greater proportion of bacteria from the phylum Bacteroidetes in insects fed artificial diet constituted the main difference between this group and those reared on foliage; within the phylum Proteobacteria, the presence of the genus Bradyrhizobium was also unique to insects reared on artificial diet. Strikingly, a Bray-Curtis analysis showed important differences in microbial diversity among the treatment groups, pointing to the importance of diet and environment in defining the spruce budworm midgut microbiota. PMID:26636571

  17. Genetic structure of Daphnia galeata populations in Eastern China.

    PubMed

    Wei, Wenzhi; Gießler, Sabine; Wolinska, Justyna; Ma, Xiaolin; Yang, Zhong; Hu, Wei; Yin, Mingbo

    2015-01-01

    This study presents the first examination of the genetic structure of Daphnia longispina complex populations in Eastern China. Only one species, D. galeata, was present across the eight investigated lakes; as identified by taxon assignment using allelic variation at 15 microsatellite loci. Three genetically differentiated D. galeata subgroups emerged independent of the type of statistical analysis applied. Thus, Bayesian clustering, discriminant analysis based on results from factorial correspondence analysis, and UPGMA clustering consistently showed that populations from two neighbouring lakes were genetically separated from a mixture of genotypes found in other lakes, which formed another two subgroups. Clonal diversity was high in all D. galeata populations, and most samples showed no deviation from Hardy-Weinberg equilibrium, indicating that clonal selection had little effect on the genetic diversity. Overall, populations did not cluster by geographical origin. Further studies will show if the observed pattern can be explained by natural colonization processes or by recent anthropogenic impact on predominantly artificial lakes.

  18. Crustal Structure beneath the Eastern Tibetan Plateau from Receiver Functions

    NASA Astrophysics Data System (ADS)

    Peng, Y.; Wu, J.; Liu, K. H.; Gao, S. S.

    2016-12-01

    To provide new constraints on crustal structure and the mechanisms responsible for the uplift and crustal thickening of the eastern Tibetan Plateau, the thicknesses and Vp/Vs ratios of the upper and lower crust beneath 72 seismic stations on the eastern Tibetan Plateau and Sichuan Basin are obtained by stacking P-to- S converted phases from the Moho and an intracrustal discontinuity, which may either be the top of the mafic lower crust, or the top of the crystalline crust for areas with a thick (more than 10 km) sedimentary rock layer. The resulting crustal thickness generally decreases from the SW to NE from 64 km in the Bayan Har Block to 32 km in the Sichuan Basin, and the overwhelmingly intermediate crustal Vp/Vs ratio in the Bayan Har and Yangtze Blocks and the Qinling Orogenic Belt indicate an overall intermediate to felsic crust composition. Resulting high lower-crustal Vp/Vs ratios in the Litang Block are consistent with the presence of a channel flow system, while the normal to lower-than- normal lower-crustal Vp/Vs values beneath the rest of the study area suggest the absence of lower-crustal melting. The Longmenshan Block and the vicinity of the Chuxiong Basin are characterized by high upper- crustal Vp/Vs values, probably reflecting widespread existence of fluid-filled extensional fractures, which have been revealed by previous crustal anisotropy analyses. The upper and lower crustal thicknesses and Vp/Vs observations provide a tighter control on crustal structure and properties than those obtained using the traditional H-k stacking method which gives averaged values for the entire crust.

  19. Lagged cumulative spruce budworm defoliation affects the risk of fire ignition in Ontario, Canada.

    PubMed

    James, Patrick M A; Robert, Louis-Etienne; Wotton, B Mike; Martell, David L; Fleming, Richard A

    2017-03-01

    Detailed understanding of forest disturbance interactions is needed for effective forecasting, modelling, and management. Insect outbreaks are a significant forest disturbance that alters forest structure as well as the distribution and connectivity of combustible fuels at broad spatial scales. The effect of insect outbreaks on fire activity is an important but contentious issue with significant policy consequences. The eastern spruce budworm (Choristoneura fumiferana) is a native defoliating insect in eastern North America whose periodic outbreaks create large patches of dead fir and spruce trees. Of particular concern to fire and forest managers is whether these patches represent an increased fire risk, if so, for how long, and how the relationship between defoliation and fire risk varies through space and time. Previous work suggests a temporary increase in flammability in budworm-killed forests, but regional and seasonal variability in these relationships has not been examined. Using an extensive database on historical lightning-caused fire ignitions and spruce budworm defoliation between 1963 and 2000, we assess the relative importance of cumulative defoliation and fire weather on the probability of ignition in Ontario, Canada. We modeled fire ignition using a generalized additive logistic regression model that accounts for temporal autocorrelation in fire weather. We compared two ecoregions in eastern Ontario (Abitibi Plains) and western Ontario (Lake of the Woods) that differ in terms of climate, geomorphology, and forest composition. We found that defoliation has the potential to both increase and decrease the probability of ignition depending on the time scale, ecoregion, and season examined. Most importantly, we found that lagged spruce budworm defoliation (8-10 yr) increases the risk of fire ignition whereas recent defoliation (1 yr) can decrease this risk. We also found that historical defoliation has a greater influence on ignition risk during the

  20. Spruce beetle-induced changes to Engelmann spruce foliage flammability

    Treesearch

    Wesley G. Page; Michael J. Jenkins; Justin B. Runyon

    2014-01-01

    Intermountain Engelmann spruce (Picea engelmannii Parry ex Engelm) stands affected by the spruce beetle (Dendroctonus rufipennis Kirby) represent a unique and growing fuel complex. In this study, we quantified and compared the changes in moisture content, chemistry, and flammability of foliage from trees in three crown condition classes: unattacked (green [G]),...

  1. Combined effect of elevated UVB, elevated temperature and fertilization on growth, needle structure and phytochemistry of young Norway spruce (Picea abies) seedlings.

    PubMed

    Virjamo, Virpi; Sutinen, Sirkka; Julkunen-Tiitto, Riitta

    2014-07-01

    Simultaneously with warming climate, other climatic and environmental factors are also changing. Here, we investigated for the first time the effects of elevated temperature, increased ultraviolet-B (UVB) radiation, fertilization and all combinations of these on the growth, secondary chemistry and needle structure of 1-year-old Norway spruce (Picea abies (L.) Karst.) seedlings in an outdoor experiment. After one growing season, elevated temperature increased root : shoot ratio and concentrations of needle piperidine alkaloids, while concentrations of needle catechins and acetophenones and bark flavonoids decreased compared with ambient temperature seedlings. UVB-radiation increased concentrations of bark condensed tannins, while fertilization increased total biomass and concentrations of needle catechins. In addition to the main effects, concentrations of some individual phenolic compounds showed UV × temperature or UV × temperature × fertilization interactions, and fertilization modified temperature response on root : shoot ratio. All the treatments described here affected the defence chemistry profiles of the seedlings, which may imply some changes in plant-herbivore interactions in connection with changing climate. The interactions between treatments indicate a need for further experiments involving several simultaneously affecting environmental changes. © 2013 John Wiley & Sons Ltd.

  2. Profiling functions of ectomycorrhizal diversity and root structuring in seedlings of Norway spruce (Picea abies) with fast- and slow-growing phenotypes.

    PubMed

    Velmala, Sannakajsa M; Rajala, Tiina; Heinonsalo, Jussi; Taylor, Andy F S; Pennanen, Taina

    2014-01-01

    We studied the role of taxonomical and functional ectomycorrhizal (ECM) fungal diversity in root formation and nutrient uptake by Norway spruce (Picea abies) seedlings with fast- and slow-growing phenotypes. Seedlings were grown with an increasing ECM fungal diversity gradient from one to four species and sampled before aboveground growth differences between the two phenotypes were apparent. ECM fungal colonization patterns were determined and functional diversity was assayed via measurements of potential enzyme activities of eight exoenzymes probably involved in nutrient mobilization. Phenotypes did not vary in their receptiveness to different ECM fungal species. However, seedlings of slow-growing phenotypes had higher fine-root density and thus more condensed root systems than fast-growing seedlings, but the potential enzyme activities of ectomycorrhizas did not differ qualitatively or quantitatively. ECM species richness increased host nutrient acquisition potential by diversifying the exoenzyme palette. Needle nitrogen content correlated positively with high chitinase activity of ectomycorrhizas. Rather than fast- and slow-growing phenotypes exhibiting differing receptiveness to ECM fungi, our results suggest that distinctions in fine-root structuring and in the belowground growth strategy already apparent at early stages of seedling development may explain later growth differences between fast- and slow-growing families.

  3. Vertical fine structure observations in the eastern equatorial Pacific

    SciTech Connect

    Hayes, S.P.

    1981-11-20

    Measurements of vertical displacement and horizontal velocity finestructure near the equator at 110/sup 0/W in the eastern Pacific Ocean are reported. Profiles were scaled to a constant Bruent-Vaeisaelae frequency ocean (N/sub 0/ = 1 cph) in accordance with a WKBJ approximation. A total of 57 CTD casts between 3/sup 0/N and 3/sup 0/S taken during five cruises in 1979 were analyzed. Results show an equatorial enhancement of vertical displacement is similar variance for vertical wavelengths longer than 50 sdbar (stretched decibars). This enhancement is similar to that which has been reported at 125/sup 0/W and 179/sup 0/E. Difference between locations can be accounted for by the observed temporal variability at 110/sup 0/W. Coherence between vertical displacement profiles separated in time by dealys of 2 hours to 120 hour indicate that the high wave number structures were largely associated with time scales of 4 days and less. Meridionally, vertical structures longer than 300 sdbar were coherent within 50 km of the equator. We interpret this vertical displacement fine structure enhancement as high wave number equatorially trapped inertial-gravity waves. The velocity fine structure measurements in July 1979 also indicate equatorially enhanced horizontal kinetic energy for vertical wave lengths longer than 100 sdbar. The velocity structures persisted over the 56 hour of measurement and appeared to have longer time scales than the vertical displacements. Meridional energy measurement and appeared to have longer time scales than the vertical displacements. Meridional energy exceeded zonal energy; however, the two components were coherent. We interpret these velocity structures as inertial-gravity waves which were produced off the equator and are propagating through the equatorial region.

  4. Genetic structure, diversity, and inbreeding of eastern white pine under different management conditions

    Treesearch

    Paula E. Marquardt; Craig S. Echt; Bryan K. Epperson; Dan M. Pubanz

    2007-01-01

    Resource sustainability requires a thorough understanding of the influence of forest management programs on the conservation of genetic diversity in tree populations. To observe how differences in forest structure affect the genetic structure of eastern white pine (Pinus strobus L.), we evaluated six eastern white pine sites across the 234000 acre (1...

  5. Crustal structure of the Eastern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Nwafor, Emeka

    The Gulf of Mexico initiated in the Late Triassic as South America and Africa separated from North America during the break up of Pangea. Previous studies indicate three models for the opening of the GOM. These include counter clockwise rotation of the Yucatan Block, rotation of the Yucatan Block about the same pole of rotation as those describing seafloor spreading in the central North Atlantic, and clockwise rotation of the Yucatan Block. There is much debate about the margin type and the crustal structure of the Eastern Gulf of Mexico (EGOM), especially below the depth of 6 km where crustal structure is poorly imaged on seismic reflection data. Two 2.5-D forward gravity and magnetic models across the margin are presented. These are constrained by basement picks from sparse seismic reflection and refraction data, spectral analysis of gravity data to determine the depth to source, magnetic susceptibility derived from results from other margins, the empirical relationship between P-wave velocity and density, and crustal scale isostatic modeling. The models, combined with a kinematic reconstruction of the GOM, show that: 1) it is a rifted margin; 2) the point where the Moho deepens downward from ˜17 km to ˜32 km is approximately 50 km outboard of the topographic shelf edge; 3) the carbonate bank retreated by several kilometers from its original termination due to the action of contourite currents; 4) extension and subsidence was accommodated with little shallow brittle faulting; 5) oceanic lithosphere is possibly outboard of the EGOM continental slope.

  6. SPRUCE experiment data infrastructure

    NASA Astrophysics Data System (ADS)

    Krassovski, M.; Hanson, P. J.; Boden, T.; Riggs, J.; Nettles, W. R.; Hook, L. A.

    2013-12-01

    The Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL), USA has provided scientific data management support for the US Department of Energy and international climate change science since 1982. Among the many data activities CDIAC performs are design and implementation of the data systems. One current example is the data system and network for SPRUCE experiment. The SPRUCE experiment (http://mnspruce.ornl.gov) is the primary component of the Terrestrial Ecosystem Science Scientific Focus Area of ORNL's Climate Change Program, focused on terrestrial ecosystems and the mechanisms that underlie their responses to climatic change. The experimental work is to be conducted in a bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The site is located at the southern margin of the boreal peatland forest. Experimental work in the 8.1-ha S1 bog will be a climate change manipulation focusing on the combined responses to multiple levels of warming at ambient or elevated CO2 (eCO2) levels. The experiment provides a platform for testing mechanisms controlling the vulnerability of organisms, biogeochemical processes and ecosystems to climatic change (e.g., thresholds for organism decline or mortality, limitations to regeneration, biogeochemical limitations to productivity, the cycling and release of CO2 and CH4 to the atmosphere). The manipulation will evaluate the response of the existing biological communities to a range of warming levels from ambient to +9°C, provided via large, modified open-top chambers. The ambient and +9°C warming treatments will also be conducted at eCO2 (in the range of 800 to 900 ppm). Both direct and indirect effects of these experimental perturbations will be analyzed to develop and refine models needed for full Earth system analyses. SPRUCE provides wide range continuous and discrete measurements. To successfully manage SPRUCE data flow

  7. Diversifying coevolution between crossbills and black spruce on Newfoundland.

    PubMed

    Parchman, Thomas L; Benkman, Craig W

    2002-08-01

    Coevolution is increasingly recognized as an important process structuring geographic variation in the form of selection for many populations. Here we consider the importance of a geographic mosaic of coevolution to patterns of crossbill (Loxia) diversity in the northern boreal forests of North America. We examine the relationships between geographic variation in cone morphology, bill morphology, and feeding performance to test the hypothesis that, in the absence of red squirrels (Tamiasciurus hudsonicus), black spruce (Picea mariana) has lost seed defenses directed at Tamiasciurus and that red crossbills (L curvirostra) and black spruce have coevolved in an evolutionary arms race. Comparisons of cone morphology and several indirect lines of evidence suggest that black spruce has evolved defenses in response to Tamiasciurus on mainland North America but has lost these defenses on Newfoundland. Cone traits that deter crossbills, including thicker scales that require larger forces to separate, are elevated in black spruce on Newfoundland, and larger billed crossbills have higher feeding performances than smaller billed crossbills on black spruce cones from Newfoundland. These results imply that the large bill of the Newfoundland crossbill (L. c. percna) evolved as an adaptation to the elevated cone defenses on Newfoundland and that crossbills and black spruce coevolved in an evolutionary arms race on Newfoundland during the last 9000 years since glaciers retreated. On the mainland where black spruce is not as well defended against crossbills, the small-billed white-winged crossbill (L leucoptera leucoptera) is more efficient and specializes on seeds in the partially closed cones. Finally, reciprocal adaptations between crossbills and conifers are replicated in black spruce and Rocky Mountain lodgepole pine (Pinus contorta ssp. latifolia), with coevolution most pronounced in isolated populations where Tamiasciurus are absent as a competitor. This study further

  8. Structural Model of the Tucupita Field, Eastern Venezuela Basin

    NASA Astrophysics Data System (ADS)

    Arteaga, L. A.

    2013-05-01

    The Tucupita Field has an area of 73,51 Km2, is located between the states of Monagas and Delta Amacuro, geologically is located at the greater Temblador area in the Eastern Venezuela Basin, where the Oficina Formation's sands represent the main hydrocarbons reservoirs. From the results of the seismic reprocessing realized by Fusion Petroleum Technologies, Inc., the structural model of this field was done as initial step to the geocellular model of the Oficina-40 Reservoir, which was defined as a Faulted Relay Ramp, where the normal faults are dominant with NE-SW orientation Introduction The Tucupita Field is a mature oilfield at the greater Temblador area, however most of the wells were completed in the upper sands, therefore the main study is focused in the geological characterization of the Oficina-40 Reservoir's lower sands, starting by the structural model Previous Studies 1. Proyecto Tucupita 3D The seismic data of the Tucupita Field were adquired in 1996 by Western Atlas of Venezuela for the Benton Vinccler Company. The UTM coordinates of the wells used in this project, have been taken to make this geological model 2. Soporte Geofísico Integrado The seismic project Tucupita was processed by Fusion Petroleum Technologies Inc., in Houston and consisted of reprocessing and pre-stack migration in time (PSTM) and pre-stack migration in depth (PSDM), this data belong to the Petrodelta Company Based on the regional stratigraphy, were validated the "picks" to make the structural sections to support research with hard data. After, it proceeded to interpret the structural style of the field from the seismic amplitude cube. Then, it was done the faults modelling and the stratigraphic horizons to carry out the geocellular model Three structural sections were realized, which was interpreted like a faulted monocline, whose peak is located southward, where justly the wells are located. The contact oil-water was interpreted to -5648'. Echelon faults were interpreted in a

  9. Evolution of volcanism around the eastern sector of Mt. Etna, inland and offshore, in the structural framework of eastern Sicily

    NASA Astrophysics Data System (ADS)

    Patané, Giuseppe; Agostino, Ivan; La Delfa, Santo; Leonardi, Riccardo

    2009-04-01

    The authors highlight a new perspective to understanding the volcanism in the Mt. Etna eastern sector, inland and offshore, based on original studies of the sea floor off the Ionian coast of Etna by means of various direct surveying methods (underwater explorations) and indirect ones (bathymetric reconstructions using echosounders). They also propose a new interpretation of geophysical, geochemical and structural surveys carried out over the last two decades. Results show that eastern Etnean sector's volcanism extends as far as the Ionian Sea, to a maximum distance from the coast of probably about 20 km. In their opinion, the absence of outcropping apparatuses in the lower eastern flank of Etna is due to these apparatuses being buried by a large detritic formation ("Chiancone") due to the dismantling of the Ancient Alkaline Centres (AAC) localised to the West. The authors consider the structures highlighted by the study of the Digital Elevation Model (DEM) of the Ionian sea floor and by the Multibeam analysis (Marani et al., 2004. From Seafloor to Deep Mantle: Architecture of the Tyrrhenian Backarc Basin, vol. 44. Mem. Descr. Carta Geol. Ital. pp. 1-2) to be of a volcanic nature. This hypothesis opens up a new field of study within the evolution of the eastern Etnean edge's volcanism, inland and offshore, in the last 500 Ky and would further confirm the eruptive axes migration from East to West.

  10. Climate-Induced Mortality of Spruce Stands in Belarus

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

    2015-01-01

    The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

  11. Climate-Induced Mortality of Spruce Stands in Belarus

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

    2015-01-01

    The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

  12. Climate-induced mortality of spruce stands in Belarus

    NASA Astrophysics Data System (ADS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

    2015-12-01

    The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

  13. Densities of breeding birds and changes in vegetation in an alaskan boreal forest following a massive disturbance by spruce beetles

    USGS Publications Warehouse

    Matsuoka, S.M.; Handel, C.M.; Ruthrauff, D.R.

    2001-01-01

    We examined bird and plant communities among forest stands with different levels of spruce mortality following a large outbreak of spruce beetles (Dendroctonus rufipennis (Kirby)) in the Copper River Basin, Alaska. Spruce beetles avoided stands with black spruce (Picea mariana) and selectively killed larger diameter white spruce (Picea glauca), thereby altering forest structure and increasing the dominance of black spruce in the region. Alders (Alnus sp.) and crowberry (Empetrum nigrum) were more abundant in areas with heavy spruce mortality, possibly a response to the death of overstory spruce. Grasses and herbaceous plants did not proliferate as has been recorded following outbreaks in more coastal Alaskan forests. Two species closely tied to coniferous habitats, the tree-nesting Ruby-crowned Kinglet (Regulus calendula) and the red squirrel (Tamiasciurus hudsonicus), a major nest predator, were less abundant in forest stands with high spruce mortality than in low-mortality stands. Understory-nesting birds as a group were more abundant in forest stands with high levels of spruce mortality, although the response of individual bird species to tree mortality was variable. Birds breeding in stands with high spruce mortality likely benefited reproductively from lower squirrel densities and a greater abundance of shrubs to conceal nests from predators.

  14. Genetic structure of the invasive tree Ailanthus altissima in eastern United States cities

    Treesearch

    Preston R. Aldrich; Joseph S. Briguglio; Shyam N. Kapadia; Minesh U. Morker; Ankit Rawal; Preeti Kalra; Cynthia D. Huebner; Gary K. Greer

    2010-01-01

    Ailanthus altissima is an invasive tree from Asia. It now occurs in most US states, and although primarily an urban weed, it has become a problem in forested areas especially in the eastern states. Little is known about its genetic structure. We explore its naturalized gene pool from 28 populations, mostly of the eastern US where infestations are...

  15. The historical disturbance regime of mountain Norway spruce forests in the Western Carpathians and its influence on current forest structure and composition.

    PubMed

    Janda, Pavel; Trotsiuk, Volodymyr; Mikoláš, Martin; Bače, Radek; Nagel, Thomas A; Seidl, Rupert; Seedre, Meelis; Morrissey, Robert C; Kucbel, Stanislav; Jaloviar, Peter; Jasík, Marián; Vysoký, Juraj; Šamonil, Pavel; Čada, Vojtěch; Mrhalová, Hana; Lábusová, Jana; Nováková, Markéta H; Rydval, Miloš; Matějů, Lenka; Svoboda, Miroslav

    2017-03-15

    In order to gauge ongoing and future changes to disturbance regimes, it is necessary to establish a solid baseline of historic disturbance patterns against which to evaluate these changes. Further, understanding how forest structure and composition respond to variation in past disturbances may provide insight into future resilience to climate-driven alterations of disturbance regimes. We established 184 plots (mostly 1000 m(2)) in 14 primary mountain Norway spruce forests in the Western Carpathians. On each plot we surveyed live and dead trees and regeneration, and cored around 25 canopy trees. Disturbance history was reconstructed by examining individual tree growth trends. The study plots were further aggregated into five groups based on disturbance history (severity and timing) to evaluate and explain its influence on forest structure. These ecosystems are characterized by a mixed severity disturbance regime with high spatiotemporal variability in severity and frequency. However, periods of synchrony in disturbance activity were also found. Specifically, a peak of canopy disturbance was found for the mid-19th century across the region (about 60% of trees established), with the most important periods of disturbance in the 1820s and from the 1840s to the 1870s. Current stand size and age structure were strongly influenced by past disturbance activity. In contrast, past disturbances did not have a significant effect on current tree density, the amount of coarse woody debris, and regeneration. High mean densities of regeneration with height >50 cm (about 1400 individuals per ha) were observed. Extensive high severity disturbances have recently affected Central European forests, spurring a discussion about the causes and consequences. We found some evidence that forests in the Western Carpathians were predisposed to recent severe disturbance events as a result of synchronized past disturbance activity, which partly homogenized size and age structure and made recent

  16. 1. 20472009 SPRUCE ST. RUNS FROM LEFT TO RIGHT. SOUTH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. 2047-2009 SPRUCE ST. RUNS FROM LEFT TO RIGHT. SOUTH (FRONT) FACADES. VIEW LOOKING NORTHEAST - Spruce Street Area Study, 2009-2045 Spruce Street (Houses), Spruce Street, north side, Philadelphia, Philadelphia County, PA

  17. Growth and yield of white spruce plantations in the Lake States (a literature review).

    Treesearch

    H. Michael Rauscher

    1984-01-01

    This summary of the white spruce literature covers the structure, site relations, population dynamics, and cultural practices applicable to established plantations in the Lake States. The objective of this paper is to assemble and organize all information relevant to the silviculture, growth, and yield of white spruce plantations in the Lake States .

  18. Exploring the Alaskan black spruce ecosystem: variability in species composition, ecosystem function, and fire history

    Treesearch

    T.N. Hollingsworth

    2008-01-01

    In this overview, I present extensive studies looking at the structure and function of the black spruce (Picea mariana) ecosystem of the boreal region of interior Alaska. One of the studies provides a classification of black spruce communities, the most abundant forest type in the region. Other studies examine large-scale processes that drive this...

  19. A density management diagram for Norway spruce in the temperate Europe montane region

    Treesearch

    Giorgio Vacchiano; R. Justin DeRose; John D. Shaw; Miroslav Svoboda; Renzo Motta

    2013-01-01

    Norway spruce is one of the most important conifer tree species in Europe, paramount for timber provision, habitat, recreation, and protection of mountain roads and settlements from natural hazards. Although natural Norway spruce forests exhibit diverse structures, even-aged stands can arise after disturbance or as the result of common silvicultural practice, including...

  20. Spruce beetle (Coleoptera: Scolytidae) response to traps baited with selected semiochemicals in Utah.

    Treesearch

    Darrell W. Ross; Gary E. Daterman; A. Steven. Munson

    2005-01-01

    Spruce beetle, Dendroctonus rufipennis (Kirby), populations periodically reach outbreak densities throughout the range of spruce, Picea spp., in western North America. During outbreaks it may kill thousands to millions of trees over vast areas, dramatically altering forest structure, composition, and ecological processes, thus impacting a variety...

  1. Structure and tectonic setting of the eastern Tehachapi Range, California

    SciTech Connect

    Wood, D.J.; Saleeby, J.B.; Silver, L.T. . Division of Geological and Planetary Sciences)

    1993-04-01

    In the easternmost Tehachapi mountains a moderately SE dipping fault zone with an irregular trace juxtaposes high grade ductilely deformed footwall gneisses against a cataclastically deformed granitic hanging wall complex from Tehachapi Valley to the Garlock FZ. The fault zone exhibits evidence of both ductile and brittle deformation. Moderately SE plunging stretching lineations and sense of shear indicators in the footwall suggest normal displacement and the sole of the hanging wall consists of a chloritic breccia. The footwall consists of garnet-amphibolite grade orthogneiss, paragneiss, and marble, locally protomylonitic, folded into presently SW vergent isoclinal folds with a penetrative, NW trending, moderately NE dipping foliation. This gneiss complex hosts a 0.2 to 0.8 km wide, NW tending, shallow NE dipping ductile shear zone, called here the eastern Tehachapi shear zone (ETSZ). The ETSZ appears to post-date much of the isoclinal folding in the gneisses. The ETSZ is inferred to continue north of Tehachapi valley (Ross, 1989) where it steepens and swings to a more northerly trend into the Lake Isabella region where it has been called the proto-Kern Canyon fault zone. A post ETSZ deformation refolded the gneisses into open, upright folds with moderately NE plunging axes. Juxtaposition of the gneisses and the cataclastically deformed granitic hanging wall rocks occurred during and/or after this post ETSZ folding event. In the structurally lowest levels of the gneiss complex exposed along the Garlock fault, quartz diorite orthogneiss becomes increasingly deformed downward with an NE striking, moderately NW dipping mylonitic fabric. The youngest deformation in the areas is a series of WNW trending, regional scale antiforms and synforms which exert a first order control on the topography of the region.

  2. Fire severity unaffected by spruce beetle outbreak in spruce-fir forests in southwestern Colorado.

    PubMed

    Andrus, Robert A; Veblen, Thomas T; Harvey, Brian J; Hart, Sarah J

    2016-04-01

    Recent large and severe outbreaks of native bark beetles have raised concern among the general public and land managers about potential for amplified fire activity in western North America. To date, the majority of studies examining bark beetle outbreaks and subsequent fire severity in the U.S. Rocky Mountains have focused on outbreaks of mountain pine beetle (MPB; Dendroctonus ponderosae) in lodgepole pine (Pinus contorta) forests, but few studies, particularly field studies, have addressed the effects of the severity of spruce beetle (Dendroctonus rufipennis Kirby) infestation on subsequent fire severity in subalpine Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests. In Colorado, the annual area infested by spruce beetle outbreaks is rapidly rising, while MPB outbreaks are subsiding; therefore understanding this relationship is of growing importance. We collected extensive field data in subalpine forests in the eastern San Juan Mountains, southwestern Colorado, USA, to investigate whether a gray-stage (< 5 yr from outbreak to time of fire) spruce beetle infestation affected fire severity. Contrary to the expectation that bark beetle infestation alters subsequent fire severity, correlation and multivariate generalized linear regression analysis revealed no influence of pre-fire spruce beetle severity on nearly all field or remotely sensed measurements of fire severity. Findings were consistent across moderate and extreme burning conditions. In comparison to severity of the pre-fire beetle outbreak, we found that topography, pre-outbreak basal area, and weather conditions exerted a stronger effect on fire severity. Our finding that beetle infestation did not alter fire severity is consistent with previous retrospective studies examining fire activity following other bark beetle outbreaks and reiterates the overriding influence of climate that creates conditions conducive to large, high-severity fires in the subalpine zone of Colorado

  3. Social Structure and Social Change in Eastern Europe.

    ERIC Educational Resources Information Center

    Fischer, George; Schenkel, Walter

    This specialized bibliography of scholarly writings since 1945 on Eastern Europe covers the countries of Albania, Bulgaria, Czechoslovakia, Greece, Hungary, Poland, Romania, and Yugoslavia. Distinct entries number about 700 and cover works published in English in the United States and Great Britain and also sources in French and German published…

  4. Oak composition and structure in the eastern United States

    Treesearch

    W. Keith Moser; Mark Hansen; Will McWilliams; Ray Sheffield

    2006-01-01

    Although oak species currently occupy a dominant position in most eastern deciduous forests, particularly on upland sites, many scientists and managers have expressed concern about the future of this genus in the absence of the disturbance patterns that facilitated its establishment up to now. Reductions in timber harvesting and fire in particular may give the...

  5. Social Structure and Social Change in Eastern Europe.

    ERIC Educational Resources Information Center

    Fischer, George; Schenkel, Walter

    This specialized bibliography of scholarly writings since 1945 on Eastern Europe covers the countries of Albania, Bulgaria, Czechoslovakia, Greece, Hungary, Poland, Romania, and Yugoslavia. Distinct entries number about 700 and cover works published in English in the United States and Great Britain and also sources in French and German published…

  6. [The spatial structure of demographic behavior in Eastern Europe].

    PubMed

    Decroly, J

    1991-01-01

    The author uses data from the recently published "Atlas de la population europeenne" to identify the unique demographic features of the countries of Eastern Europe. Specifically, he examines the extent to which political factors have affected demographic indicators such as fertility, mortality, migration, and spatial distribution in this region.

  7. ASSOCIATIONS OF EASTERN REDCEDAR AND COMMUNITY STRUCTURE OF SMALL MAMMALS

    EPA Science Inventory

    Increased abundance of eastern redcedar (Juniperus virginianas), a native but invasive species in the Great Plains, has been associated with several changes in ecosystem function. It can lead to a reduction in herbaceous biomass in the canopy zone, alter species composition, and...

  8. ASSOCIATIONS OF EASTERN REDCEDAR AND COMMUNITY STRUCTURE OF SMALL MAMMALS

    EPA Science Inventory

    Increased abundance of eastern redcedar (Juniperus virginianas), a native but invasive species in the Great Plains, has been associated with several changes in ecosystem function. It can lead to a reduction in herbaceous biomass in the canopy zone, alter species composition, and...

  9. White spruce meets black spruce: dispersal, postfire establishment, and growth in a warming climate

    Treesearch

    C. Wirth; J.W. Lichstein; J. Dushoff; A. Chen; F.S.III. Chapin

    2008-01-01

    Local distributions of black spruce (Picea mariana) and white spruce (Picea glauca) are largely determined by edaphic and topographic factors in the interior of Alaska, with black spruce dominant on moist permafrost sites and white spruce dominant on drier upland sites. Given the recent evidence for climate warming and...

  10. The Crustal Structure and Seismicity of Eastern Venezuela

    NASA Astrophysics Data System (ADS)

    Schmitz, M.; Martins, A.; Sobiesiak, M.; Alvarado, L.; Vasquez, R.

    2001-12-01

    Eastern Venezuela is characterized by a moderate to high seismicity, evidenced recently by the 1997 Cariaco earthquake located on the El Pilar Fault, a right lateral strike slip fault which marks the plate boundary between the Caribbean and South-American plates in this region. Recently, the seismic activity seems to migrate towards the zone of subduction of the Lesser Antilles in the northeast, where a mb 6.0 earthquake occurred in October 2000 at 120 km of depth. Periodical changes in the seismic activity are related to the interaction of the stress fields of the strike-slip and the subduction regimes. The seismic activity decreases rapidly towards to the south with some disperse events on the northern edge of the Guayana Shield, related to the Guri fault system. The crustal models used in the region are derived from the information generated by the national seismological network since 1982 and by microseismicity studies in northeastern Venezuela, coinciding in a crustal thickness of about 35 km in depth. Results of seismic refraction measurements for the region were obtained during field campains in 1998 (ECOGUAY) for the Guayana Shield and the Cariaco sedimentary basin and in 2001 (ECCO) for the Oriental Basin. The total crustal thickness decreases from about 45 km on the northern edge of the Guayana Shield to some 36 km close to El Tigre in the center of the Oriental Basin. The average crustal velocity decreases in the same sense from 6.5 to 5.8 km/s. In the Cariaco sedimentary basin a young sedimentary cover of 1 km thickness with a seismic velocity of 2 km/s was derived. Towards the northern limit of the South-American plate, no deep seismic refraction data are available up to now. The improvement of the crustal models used in that region would constitute a step forward in the analysis of the seismic hazard. Seismic refraction studies funded by CONICIT S1-97002996 and S1-2000000685 projects and PDVSA (additional drilling and blasting), recording equipment

  11. FT–Raman investigation of bleaching of spruce thermomechanical pulp

    Treesearch

    U.P. Agarwal; L.L. Landucci

    2004-01-01

    Spruce thermomechanical pulp was bleached initially by alkaline hydrogen peroxide and then by sodium dithionite and sodium borohydride. Near-infrared Fourier-transform–Raman spectroscopy revealed that spectral differences were due primarily to coniferaldehyde and p-quinone structures in lignin, new direct evidence that bleaching removes p-quinone structures. In...

  12. Mice and voles prefer spruce seeds

    Treesearch

    Herschel G. Abbott; Arthur C. Hart

    1961-01-01

    When spruce-fir stands in the Northeast are cut, balsam fir seedlings often predominate in the regeneration that follows. Most landowners would prefer to have the spruce; but they do not get it, and they wonder why.

  13. Deep structure of Eastern part of Bandung Basin based on 2D resistivity structure

    NASA Astrophysics Data System (ADS)

    Harja, Asep

    2013-09-01

    Bandung basin is an intramontane basin located in West Java, extending from west to east along 35 km and north to south along 15 km distance, with elevation of 660-680 m. The plain in the eastern part is the basin center with lake deposit as primary sediment filling the basin. Investigation of the subsurface structure and thickness of the basin is the main topic in this research. Beside the deeper structure of the basin, the shallow structure is also very important to be revealed since human activities are concentrated in this part. The latter is supposed to explain phenomenon related to the flood and drought that frequently occur in the area. Controlled-source audio-frequency magneto telluric (CSAMT) is a highly effective electromagnetic (EM) method to deploy in this area. Its robustness toward electromagnetic noises related to human and industrial activities particularly in the eastern part of the basin is the strong point of this method. It uses a grounded horizontal electric dipole as artificial source of electromagnetic signal that ensures data with a high signal to noise (S/N) ratio. This method is capable to map subsurface resistivity structure with high sensitivity to resistivity contras and deeper penetration. 1D inversion scheme was used to the far-field component of CSAMT data (plane wave assumption) in order to obtain resistivity cross-sections that are more suitable with the basin's structure complexity. The results show that until the depth of more than 200 m, no high resistivity structure is found. This unlikely indicated the presence of volcanic rocks beneath the area. The subsurface resistivity distribution is dominated by tens of Om, indicating that the basement comprises deep marine sediment. In addition, clay lens are also indicated in the resulting resistivity structure. Based on 2D view of resistivity cross-sections based 1D inverted and 2D inversion, it is found that a low resistivity elongation extends in southeast-northwest direction at

  14. Clinal variation at phenology-related genes in spruce: parallel evolution in FTL2 and Gigantea?

    PubMed

    Chen, Jun; Tsuda, Yoshiaki; Stocks, Michael; Källman, Thomas; Xu, Nannan; Kärkkäinen, Katri; Huotari, Tea; Semerikov, Vladimir L; Vendramin, Giovanni G; Lascoux, Martin

    2014-07-01

    Parallel clines in different species, or in different geographical regions of the same species, are an important source of information on the genetic basis of local adaptation. We recently detected latitudinal clines in SNPs frequencies and gene expression of candidate genes for growth cessation in Scandinavian populations of Norway spruce (Picea abies). Here we test whether the same clines are also present in Siberian spruce (P. obovata), a close relative of Norway spruce with a different Quaternary history. We sequenced nine candidate genes and 27 control loci and genotyped 14 SSR loci in six populations of P. obovata located along the Yenisei river from latitude 56°N to latitude 67°N. In contrast to Scandinavian Norway spruce that both departs from the standard neutral model (SNM) and shows a clear population structure, Siberian spruce populations along the Yenisei do not depart from the SNM and are genetically unstructured. Nonetheless, as in Norway spruce, growth cessation is significantly clinal. Polymorphisms in photoperiodic (FTL2) and circadian clock (Gigantea, GI, PRR3) genes also show significant clinal variation and/or evidence of local selection. In GI, one of the variants is the same as in Norway spruce. Finally, a strong cline in gene expression is observed for FTL2, but not for GI. These results, together with recent physiological studies, confirm the key role played by FTL2 and circadian clock genes in the control of growth cessation in spruce species and suggest the presence of parallel adaptation in these two species.

  15. Modelling spruce bark beetle infestation probability

    Treesearch

    Paulius Zolubas; Jose Negron; A. Steven Munson

    2009-01-01

    Spruce bark beetle (Ips typographus L.) risk model, based on pure Norway spruce (Picea abies Karst.) stand characteristics in experimental and control plots was developed using classification and regression tree statistical technique under endemic pest population density. The most significant variable in spruce bark beetle...

  16. Growth declines in red spruce

    SciTech Connect

    McLaughlin, S.B. ); Adams, H.S. )

    1987-10-01

    In this letter, the authors take issue with Zedaker, Hyink, and Smith who have indicated that observed red spruce growth declines can be expected based on growth trends for even-aged stands of red spruce as documented in Meyer (1929). Recently, an examination was made of stand stocking levels at 750 sites where red spruce were cored and neither the rate of growth decline nor the extent of mortality were found to be related to stand stocking levels or previous disturbance history. The authors conclude that the Meyer data do not represent an appropriate model for stand dynamics of old-growth, high-elevation stands and no not adequately explain the growth declines observed at many of those sites.

  17. Indicators of Population Viabllity in Red Spruce, Picea rubens. I. Reproductive Traits and Fecundity

    Treesearch

    A. Mosseler; J.E. Major; J.D. Simpson; B. Daigle; K. Lange; Y.S. Park; K.H Johnsen; O.P. Rajora

    2000-01-01

    Red spruce (Picea rubens Sarg.) has experienced a substantial decline across most of its range in eastern North America over the past centmy and probably also in the disjunct Ontario populations where it now occurs only in small isolated stands. Measurements of cone and seed traits from natural populations were used as indicators of the...

  18. The Seismicity and Crustal Structure of Continental Eastern Russia

    NASA Astrophysics Data System (ADS)

    Mackey, K. G.; Nichols, M. L.; Fujita, K.; Gounbina, L. V.; Koz'min, B. M.

    2004-12-01

    Regional networks were established under the Former Soviet Union to monitor seismic activity and evaluate seismic hazards. In eastern Russia, these networks were deployed starting in the early 1960s. The networks generally operated analog short-period instruments, with some base stations having long-period sensors. Approximately 50,000 events have been located on the continental part of eastern Russia. These earthquakes define the boundaries between three major (Pacific, North America, Eurasia), and several minor (Bering, Okhotsk, Amur, Primoria) plates. The zones of seismic activity are diffuse and indicate that deformation between these plates is distributed over a large number of faults. Major strike-slip faults can be identified both by linear trends in the larger seismicity and in satellite imagery; examples include the Ulakhan fault system, between North America and Okhotsk, the Ketanda fault system between Okhotsk and Eurasia, and a system of faults in southern Yakutia and the Stanovoi Range between Eurasia and Amur. Regional arrivals at Russian seismic stations were used to determine crustal P- and S-wave velocities. A grid search method conducted along a moving window through eastern Russia to find best-fit velocities for minimizing travel-time residuals yields a model that is consistent with the tectonic setting (cratons, rift zones). Preliminary ground-truth experiments in the Magadan district show a good fit between the determined best-fit velocities and those from industrial explosions, as do those from previous Russian seismic surveys. Earthquake relocations using these best-fit velocities, and combining data from between networks, reveal linear trends and clusters which can be associated with active faults. Considerable contamination of the Russian seismicity catalog by industrial explosions has also occurred.

  19. Wave speed structure of the eastern North American margin

    NASA Astrophysics Data System (ADS)

    Savage, B.; Covellone, B. M.; Shen, Y.

    2017-02-01

    The eastern North American margin (ENAM) is the result of nearly a billion years of continental collision and rifting. To the west of this margin lies thick continental lithosphere of the North American craton, and to the east is oceanic lithosphere in the Atlantic. The substantial changes in lithosphere thickness at this boundary are thought to drive asthenosphere upwelling along the edge of the continent. Through iterative, full-waveform, ambient noise tomography, we observe a heterogeneous low wave speed margin along the continent in the upper mantle. Multiple low wave speed features imaged within the margin are consistent with asthenospeheric upwelling due to edge-driven convection. Also within the margin are high wave speed anomalies that maybe the remnants of eclogitic delamination of the Appalachian crustal root, which contribute to convection at the margin. Edge driven, small-scale convection keeps the margin weak and thus controls the large scale plate tectonic patterns and the crustal deformation. The imaged mantle wave speed anomalies, interpreted as edge-driven convection, correlate with and may increase the likelihood of damaging earthquakes in the eastern portion of North America.

  20. Association of ring shake in eastern hemlock with tree attributes

    Treesearch

    John P. Brown; Paul E. Sendak

    2006-01-01

    Eastern hemlock (Tsuga canadensis (L.) Carr.) is a major or minor associate in many forest types in northeastern North America. There has never been the high level of demand for eastern hemlock lumber that characterizes competing softwoods like white pine and spruce. Nevertheless, periodically interest in greater utilization of eastern hemlock for...

  1. Premature Needle Loss of Spruce

    Treesearch

    Jennifer Juzwik; Joseph G. O Brien

    1990-01-01

    Premature needle loss on white, black and Norway spruce has been observed in forest plantations in Wisconsin and Minnesota during the past six years. Symptoms vary by species but usually appear first in 2-4-year old needles on lower branches. Infected needles are dropped, resulting in branch mortality that progresses upward through the crown, sometimes killing even...

  2. Growth declines in red spruce

    SciTech Connect

    Zedaker, S.M.; Hyink, D.M.; Smith, D.W.

    1987-01-01

    Over the past two decades second-growth red spruce stands in the Northeast have demonstrated declines in radial increment. Some observers are implicating air pollution as a primary cause of the declines, based on recently acquired increment cores from dominant trees. Various forms of air pollution (O/sub 3/, NO/sub x/, SO/sub 2/, and trace metals) are known to reduce growth and development of tree species, but few studies have provided concrete evidence of regional pollution-caused declines in forest ecosystems. Recently published evidence of a synchronous, consistent, and unprecedented regional decline in red spruce should be weighed against the realization that radial increment in red spruce declines naturally as stands age. Separating anthropogenic stress-caused growth patterns from natural stand dynamics requires an in-depth knowledge of forest growth and yield, tree silvics, and forest ecosystem processes. Detailed analyses of growth by stand characteristics - site index, density, elevation, stand history - will be necessary to implicate air pollution as a primary cause of red spruce decline.

  3. Pinus glabra Walt. Spruce Pine

    Treesearch

    Susan V. Kossuth; J.L. Michael

    1991-01-01

    Spruce pine (Pinus glabra), also called cedar pine, Walter pine, or bottom white pine, is a medium-sized tree that grows in limited numbers in swamps, river valleys, on hummocks, and along river banks of the southern Coastal Plain. Its wood is brittle, close-grained, nondurable, and is of limited commercial importance.

  4. Structure of the eastern Cordillera of Colombia: Implications for trap styles and regional tectonics

    SciTech Connect

    Dengo, C.A. ); Covey, M.C. )

    1993-08-01

    The northwest margin of South America has undergone multiple phases of compressional deformation beginning in the Late Cretaceous and culminating in the Pliocene-Pleistocene. The latest phases (Miocene to Pleistocene) of this deformation created the Eastern Cordillera of Colombia. Compressional structures in the Eastern Cordillera formed traps that have petroleum exploration potential; these are generally in the form of fault-bend and fault-propagation folds containing top-sealed reservoir and mature source rocks. Trap delineation, although difficult to achieve because of the poor seismic quality obtained in the region, can be accomplished by supplementing the seismic data with geometric analysis of surficial structures. 50 refs., 17 figs.

  5. Spatial patterns in forest composition and standing dead red spruce in montane forests of the Adirondacks and northern Appalachians.

    PubMed

    Craig, B W; Friedland, A J

    1991-08-01

    The decline of red spruce (Picea rubens Sarg.) in montane forests of the northeastern United States has been previously reported. The objective of this study was to assess spatial patterns, if any, in standing dead red spruce stems in the Adirondacks of New York and northern Appalachians of Vermont, New Hampshire, and Maine. A stratified random sample of 19 mountains along a west to east transect in the Adirondacks and the northern Appalachians showed that the live basal area of all species was highest in the White Mountains (34.6 m(2) ha(-1)) and lowest in the Adirondack Mountains (23.7 m(2) ha(-1)) in the Green Mountains was significantly lower than in any other region. Intact standing dead red spruce in the Adirondack and Green Mountains (30%) was significantly higher than that in the three eastern clusters (14%). The amount of intact standing dead red spruce trees increased with elevation in only the western part of the region. With the exception of the Adirondacks, there was a greater average percent dead red spruce on the west side than on the east side of each mountain. The sum of standing dead for other tree species (average 13%) showed no statistically significant patterns with region, elevation or aspect, and was significantly lower than the amount of total dead red spruce (average 42%). The standing dead red spruce patterns we observed cannot be associated with any specific causal factors at this time.

  6. Improved white spruce (Picea glauca) genome assemblies and annotation of large gene families of conifer terpenoid and phenolic defense metabolism.

    PubMed

    Warren, René L; Keeling, Christopher I; Yuen, Macaire Man Saint; Raymond, Anthony; Taylor, Greg A; Vandervalk, Benjamin P; Mohamadi, Hamid; Paulino, Daniel; Chiu, Readman; Jackman, Shaun D; Robertson, Gordon; Yang, Chen; Boyle, Brian; Hoffmann, Margarete; Weigel, Detlef; Nelson, David R; Ritland, Carol; Isabel, Nathalie; Jaquish, Barry; Yanchuk, Alvin; Bousquet, Jean; Jones, Steven J M; MacKay, John; Birol, Inanc; Bohlmann, Joerg

    2015-07-01

    White spruce (Picea glauca), a gymnosperm tree, has been established as one of the models for conifer genomics. We describe the draft genome assemblies of two white spruce genotypes, PG29 and WS77111, innovative tools for the assembly of very large genomes, and the conifer genomics resources developed in this process. The two white spruce genotypes originate from distant geographic regions of western (PG29) and eastern (WS77111) North America, and represent elite trees in two Canadian tree-breeding programs. We present an update (V3 and V4) for a previously reported PG29 V2 draft genome assembly and introduce a second white spruce genome assembly for genotype WS77111. Assemblies of the PG29 and WS77111 genomes confirm the reconstructed white spruce genome size in the 20 Gbp range, and show broad synteny. Using the PG29 V3 assembly and additional white spruce genomics and transcriptomics resources, we performed MAKER-P annotation and meticulous expert annotation of very large gene families of conifer defense metabolism, the terpene synthases and cytochrome P450s. We also comprehensively annotated the white spruce mevalonate, methylerythritol phosphate and phenylpropanoid pathways. These analyses highlighted the large extent of gene and pseudogene duplications in a conifer genome, in particular for genes of secondary (i.e. specialized) metabolism, and the potential for gain and loss of function for defense and adaptation.

  7. Cenozoic contractional reactivation of Mesozoic extensional structures in the Eastern Cordillera of Colombia

    NASA Astrophysics Data System (ADS)

    Mora, AndréS.; Parra, Mauricio; Strecker, Manfred R.; Kammer, Andreas; Dimaté, Cristina; RodríGuez, Fernando

    2006-04-01

    The Eastern Cordillera of Colombia is key to understanding the role of inherited basement anisotropies in the evolution of active noncollisional mountain belts. In particular, the Rio Blanco-Guatiquía region of the Eastern Cordillera is exemplary in displaying a variety of phenomena that document the importance of the orientation, geometry, and segmentation of preorogenic anisotropies. We document the first unambiguous evidence that extensional basement structures played an important role in determining the locus of deformation during contractional reactivation in the Eastern Cordillera. Detailed structural field mapping and analysis of industry seismic reflection profiles have helped to identify the inherited San Juanito, Naranjal, and Servitá normal faults and associated transfer faults as important structures that were inverted during the Cenozoic Andean orogeny. Apparently, the more internal faults in the former rift basin were not properly oriented for an efficient reactivation in contraction. However, these faults have a fundamental role as strain risers, as folding is concentrated west of them. In contrast, reactivated normal faults such as the more external Servitá fault are responsible for uplifting the eastern flank of the Eastern Cordillera. In addition, these structures are adjacent and intimately linked to the development of thin-skinned faults farther east. In part, the superimposed compression in this prestrained extensional region is compensated by lateral escape. The dominant presence of basement involved buckling and thrusting, and the restricted development of thin-skinned thrusting in this inversion orogen makes the Eastern Cordillera a close analog to the intraplate Atlas Mountains of Morocco and other inverted sectors of the Andean orogen farther south.

  8. Effects of artificial defoliation of pines on the structure and physiology of the soil fungal community of a mixed pine-spruce forest

    NASA Technical Reports Server (NTRS)

    Cullings, Ken; Raleigh, Christopher; New, Michael H.; Henson, Joan

    2005-01-01

    Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems.

  9. Effects of artificial defoliation of pines on the structure and physiology of the soil fungal community of a mixed pine-spruce forest

    NASA Technical Reports Server (NTRS)

    Cullings, Ken; Raleigh, Christopher; New, Michael H.; Henson, Joan

    2005-01-01

    Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems.

  10. Effects of Artificial Defoliation of Pines on the Structure and Physiology of the Soil Fungal Community of a Mixed Pine-Spruce Forest

    PubMed Central

    Cullings, Ken; Raleigh, Christopher; New, Michael H.; Henson, Joan

    2005-01-01

    Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems. PMID:15812031

  11. Effects of artificial defoliation of pines on the structure and physiology of the soil fungal community of a mixed pine-spruce forest.

    PubMed

    Cullings, Ken; Raleigh, Christopher; New, Michael H; Henson, Joan

    2005-04-01

    Loss of photosynthetic area can affect soil microbial communities by altering the availability of fixed carbon. We used denaturing gradient gel electrophoresis (DGGE) and Biolog filamentous-fungus plates to determine the effects of artificial defoliation of pines in a mixed pine-spruce forest on the composition of the fungal community in a forest soil. As measured by DGGE, two fungal species were affected significantly by the defoliation of pines (P < 0.001); the frequency of members of the ectomycorrhizal fungus genus Cenococcum decreased significantly, while the frequency of organisms of an unidentified soil fungus increased. The decrease in the amount of Cenococcum organisms may have occurred because of the formation of extensive hyphal networks by species of this genus, which require more of the carbon fixed by their host, or because this fungus is dependent upon quantitative differences in spruce root exudates. The defoliation of pines did not affect the overall composition of the soil fungal community or fungal-species richness (number of species per core). Biolog filamentous-fungus plate assays indicated a significant increase (P < 0.001) in the number of carbon substrates utilized by the soil fungi and the rate at which these substrates were used, which could indicate an increase in fungal-species richness. Thus, either small changes in the soil fungal community give rise to significant increases in physiological capabilities or PCR bias limits the reliability of the DGGE results. These data indicate that combined genetic and physiological assessments of the soil fungal community are needed to accurately assess the effect of disturbance on indigenous microbial systems.

  12. In vivo function of Pgβglu-1 in the release of acetophenones in white spruce

    PubMed Central

    Mageroy, Melissa H.; Lachance, Denis; Jancsik, Sharon; Parent, Geneviève; Séguin, Armand; Mackay, John

    2017-01-01

    Eastern spruce budworm (Choristoneura fumiferiana Clemens) (ESBW) is a major forest pest which feeds on young shoots of white spruce (Picea glauca) and can cause landscape level economic and ecological losses. Release of acetophenone metabolites, piceol and pungenol, from their corresponding glycosides, picein and pungenin, can confer natural resistance of spruce to ESBW. A beta-glucosidase gene, Pgβglu-1, was recently discovered and the encoded enzyme was characterized in vitro to function in the release of the defensive acetophenone aglycons. Here we describe overexpression of Pgβglu-1 in a white spruce genotype whose metabolome contains the glucosylated acetophenones, but no detectable amounts of the aglycons. Transgenic overexpression of Pgβglu-1 resulted in release of the acetophenone aglycons in planta. This work provides in vivo evidence for the function of Pgβglu-1. PMID:28698822

  13. In vivo function of Pgβglu-1 in the release of acetophenones in white spruce.

    PubMed

    Mageroy, Melissa H; Lachance, Denis; Jancsik, Sharon; Parent, Geneviève; Séguin, Armand; Mackay, John; Bohlmann, Joerg

    2017-01-01

    Eastern spruce budworm (Choristoneura fumiferiana Clemens) (ESBW) is a major forest pest which feeds on young shoots of white spruce (Picea glauca) and can cause landscape level economic and ecological losses. Release of acetophenone metabolites, piceol and pungenol, from their corresponding glycosides, picein and pungenin, can confer natural resistance of spruce to ESBW. A beta-glucosidase gene, Pgβglu-1, was recently discovered and the encoded enzyme was characterized in vitro to function in the release of the defensive acetophenone aglycons. Here we describe overexpression of Pgβglu-1 in a white spruce genotype whose metabolome contains the glucosylated acetophenones, but no detectable amounts of the aglycons. Transgenic overexpression of Pgβglu-1 resulted in release of the acetophenone aglycons in planta. This work provides in vivo evidence for the function of Pgβglu-1.

  14. Red spruce physiology and growth in response to elevated CO[sub 2], water stress and nutrient limitations

    SciTech Connect

    Samuelson, L.J.

    1992-01-01

    Spruce-fir ecosystems of the eastern United States interest scientists because of reported changes in population growth. This research examined the growth and physical responses of red spruce seedlings (Picea rubens Sarg.) to change in atmospheric CO[sub 2], water and nutrient availability to determine the response of this species to potential climatic changes. Red spruce seedlings were grown from seed for 1 year in ambient (374 ppm) or elevated (713 ppm) CO[sub 2] in combination with low or high soil fertility treatment, and well-watered or water-stressed conditions. Red spruce seedlings grown with limited nutrient and water availability increased growth in elevated CO[sub 2] as did seedlings grown with high soil fertility treatment and ample water. At 12 months of age, elevated CO[sub 2]-grown seedlings had greater dry weight, height, diameter and specific leaf weight than ambient CO[sub 2[minus

  15. Structural framework across the Bastar craton - the Eastern Ghats Granulite Belt interface: Implications for making of eastern Gondwana

    NASA Astrophysics Data System (ADS)

    Patole, Vishal; Nasipuri, Pritam

    2015-04-01

    The transformation of palaeo-continents involve breakup, dispersal and reassembly of cratonic blocks by collisional suturing that develop a network of orogenic (mobile) belts around the periphery of the stable cratons. During the collision, partial melting of the different crustal blocks produces migmatites at the craton-mobile belt interface. Thus, migmatites at the craton-mobile belt contact can provide valuable information regarding the pressure-temperature conditions of the melting of lower crust during supercontinent building processes. In this contribution, we document the structural framework across the Bastar craton- Eastern Ghats Granulite Belt (EGGB) interface that developed during the accretion of EGGB over Bastar craton. Near Bhawanipatna, Orissa, Eastern India, the granulites of the mobile belt are juxtaposed against the granitic rocks of the Bastar craton. Away from the contact domain, the cratonic granite is non-migmatitic and blasto-porphyritic in nature that gradually transforms to migmatitic variety towards the contact domain. In the non-migmatitic variety, the E-W trending stromatic leucozomes and biotite-hornblende rich fabric (S1) wraps around recrystallized K-feldspar augens. In the migmatitic variety towards the contact domain, NNE-SSW trending diatexite leucozomes (S2) are prominent and the intensity of melting and tightness of folding increases towards the contact domain. Structural measurements indicate that the S1 fabric is folded with the development of NNE-SSW axial plane with easterly plunging fold axis (50 -> 050N). To correlate the geological history of EGGB in the context of supercontinent reconstruction, the existence of a cratonic block consisting of India - Madagascar - Sri Lanka - Enderby Land-Kalahari ("IMSLEK") from 3000 Ma upto 750 Ma has been invoked by several authors. The apparent continuity of the Grenvillian metamorphic orogen along the East Antarctica-Australia-India margin has been taken as conclusive evidence for the

  16. The influence of fire on lepidopteran abundance and community structure in forested habitats of eastern Texas

    Treesearch

    D. Craig Rudolph; Charles A. Ely

    2000-01-01

    Transect surveys were used to examine the influence of fire on lepidopteran communities (Papilionoidea and Hesperioidea) in forested habitats in eastern Texas. Lepidopteran abundance was greater in pine forests where prescribed fire maintained an open mid- and understory compared to forests where fire had less impact on forest structure. Ahundance of nectar sources...

  17. Virulence structure of the eastern U.S. wheat powdery mildew population

    USDA-ARS?s Scientific Manuscript database

    Little is known about the population structure of wheat powdery mildew in the eastern 2 U.S., and the most recent report on virulence in this pathogen population involved isolates 3 collected in 1993-94. In the present study, wheat leaves naturally infected with powdery mildew 4 were collected from ...

  18. The Social Consequences of Postcommunist Structural Change: An Analysis of Suicide Trends in Eastern Europe

    ERIC Educational Resources Information Center

    Minagawa, Yuka

    2013-01-01

    Guided by Durkheim's classic theory of suicide, this article examines suicide trends and determinants in Eastern European countries for the period of 1989-2006, with particular attention given to the association between postcommunist social change and suicide mortality. I find that countries characterized by more drastic structural change…

  19. Genetic subpopulation structuring and its implications in a mature eastern white pine stand

    Treesearch

    Samuel E. Nijensohn; Paul G. Schaberg; Gary J. Hawley; Donald H. DeHayes; Donald H. DeHayes

    2005-01-01

    We examined patterns of genetic structuring within a mature eastern white pine (Pinus strobus L.) forest, using geographic information system (GIS)-based data and maps that combined genetic (isozyme analysis of 46 loci) and other tree-specific information (e.g., size, growth, age, and location) for 220 trees in Jericho, Vermont. Interconnections between genotypic...

  20. The Social Consequences of Postcommunist Structural Change: An Analysis of Suicide Trends in Eastern Europe

    ERIC Educational Resources Information Center

    Minagawa, Yuka

    2013-01-01

    Guided by Durkheim's classic theory of suicide, this article examines suicide trends and determinants in Eastern European countries for the period of 1989-2006, with particular attention given to the association between postcommunist social change and suicide mortality. I find that countries characterized by more drastic structural change…

  1. Space sequestration below ground in old-growth spruce-beech forests—signs for facilitation?

    PubMed Central

    Bolte, Andreas; Kampf, Friederike; Hilbrig, Lutz

    2013-01-01

    Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤2 mm) by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1) spruce as a central tree, (2) spruce as competitor, (3) beech as a central tree, and (4) beech as competitor. Mean values of life fine root attributes like biomass (FRB), length (FRL), and root area index (RAI) were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA) exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL) and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA), asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area. PMID:24009616

  2. Space sequestration below ground in old-growth spruce-beech forests-signs for facilitation?

    PubMed

    Bolte, Andreas; Kampf, Friederike; Hilbrig, Lutz

    2013-01-01

    Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤2 mm) by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1) spruce as a central tree, (2) spruce as competitor, (3) beech as a central tree, and (4) beech as competitor. Mean values of life fine root attributes like biomass (FRB), length (FRL), and root area index (RAI) were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA) exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL) and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA), asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area.

  3. Evidence for sexual selection on structural plumage coloration in female eastern bluebirds (Sialia sialis).

    PubMed

    Siefferman, Lynn; Hill, Geoffrey E

    2005-08-01

    Although the function of ornamental traits in males has been the focus of intensive research for decades, expression of such traits in females has received much less study. Eastern bluebirds (Sialia sialis) display structurally based ultraviolet/blue and melanin-based chestnut plumage, and in males this plumage coloration is related to both reproductive success and competitive ability. Compared to males, female bluebirds show a subdued expression of blue and chestnut ornamental coloration, and we used a combination of an aviary nutritional-stress experiment and four years of field data to test the hypothesis that coloration functions as a signal of female quality. First, we tested the effect of food intake on expression of structural and melanin coloration in female eastern bluebirds to determine whether structural or melanin coloration are condition-dependent traits. Females that were given ad libitum access to food displayed more ornamented structural coloration than females on a food-restricted diet, but there was no effect of the experiment on melanin ornamentation. Second, we used field data to assess whether female ornamentation correlated with measures of mate quality and parental effort. The structural coloration of females predicted first egg date, maternal provisioning rates, and measures of reproductive success. These data indicate that structural coloration is dependent on nutritional condition and suggest that sexual selection is acting on structurally based plumage coloration in female eastern bluebirds.

  4. Image crustal structure of eastern Oklahoma City with TOMODD

    NASA Astrophysics Data System (ADS)

    Chen, C.; Holland, A. A.; Keller, R. G.

    2012-12-01

    There has been a dramatic increase in earthquake activity in Oklahoma since 2009. This dramatic increase was also matched by a marked increase in the number of operating seismic stations within the region. The additional stations include the Earthscope Transportable Arrays and temporary stations provided by the U. S. Geological Survey. The additional seismic stations and earthquakes provide the ability to do local travel time tomography of the crust within the region. For this study we are focusing on the area near the Jones earthquake swarm, that occurred just east of Oklahoma City, and the M5.6, November 2011 Prague earthquake. Major structures are already known in the area, but little is known about crustal structure below the top of the Precambrian basement. We used regionally available and temporary seismic stations along with more than 2000 earthquakes within the region to develop a 3D tomographic model of the crust using TOMODD. The major structures within the area are the Nemaha Ridge, Wilzetta Fault, and Seminole Uplift, and they and other structures as well are expressed within the tomographic model. We are working on determining the resolution and interpretation of the tomographic images.

  5. Organic matter characteristics in boreal forest soils under stands of silver birch, Norway spruce, and Norway spruce with a mixture of silver birch

    NASA Astrophysics Data System (ADS)

    Smolander, A.; Kitunen, V.

    2012-04-01

    The aim was to study how tree species and a tree species mixture affect microbial C and N transformations and two major plant secondary compound groups, terpenes and phenolic compounds in soil. The study site was a tree-species experiment in middle-eastern part of Finland containing plots of 43-year-old silver birch, Norway spruce and Norway spruce with a mixture of silver birch (22 and 37 % birch of the total stem number). Soil was podzol and humus type mor. Samples were taken from the organic layer. C and N in the microbial biomass, rates of C mineralization (CO2 evolution), net N mineralization and nitrification, and concentrations of total water-soluble phenolic compounds, condensed tannins and different kind of terpenes were measured. Amounts of C and N in the microbial biomass and the rates of C mineralization and net N mineralization were all lower under spruce than birch, and particularly net N mineralization was stimulated by birch mixture. Concentrations of total water-soluble phenolic compounds were on a similar level, irrespective of tree species. However, there were less low-molecular-weight phenolics and more high-molecular-weight phenolics under spruce than birch. Concentrations of condensed tannins and both sesqui- and diterpenes were all higher under spruce than birch but the concentrations of triterpenes were similar in all soils. The difference between tree species was greatest with monoterpenes which were measured from both organic layer and soil atmosphere: high concentrations under spruce and negligible under birch. Birch mixture tended to decrease the concentrations of condensed tannins and mono-, sesqui- and diterpenes.

  6. Historical patterns of spruce budworm defoliation and bark beetle outbreaks in North American conifer forests: an atlas and description of digital maps

    Treesearch

    David W. Williams; Richard A. Birdsey

    2003-01-01

    This atlas presents maps of historical defoliation by the eastern and western spruce budworms and historical outbreaks of the mountain and southern pine beetles during the past half century. The maps encompass various regions of the conterminous United States and eastern Canada. This publication also serves as documentation for an extended set of digital maps, which...

  7. Integrating remote sensing and magnetic data for structural geology investigation in pegmatite areas in eastern Afghanistan

    NASA Astrophysics Data System (ADS)

    Salehi, Ratib; Saadi, Nureddin M.; Khalil, Ahmed; Watanabe, Koichiro

    2015-01-01

    This study used an integrated approach to investigate pegmatite areas in eastern Afghanistan. The analysis of surface data, including a digital elevation model (DEM), and Landsat Enhanced Thematic Mapper Plus (ETM+) images, was combined with airborne magnetic data to better understand three-dimensional geology in the area. The ETM+ and DEM data were used to map geological structures at the surface, which indicate that the area consists of two main fault systems that trend NNE and E-W. The two trends represent the remnants of reactivated structures that formed under the stress regimes generated during the tectonic evolution of eastern Afghanistan. Magnetic data indicate an NE-SW trending basin. A two-dimensional schematic model shows that the basin gradually deepens toward the SW with depths to the magnetic basement ranging between 2 and 11.5 km. The integration of the results gave new insight into the tectonic evolution and structure patterns near the pegmatites area.

  8. Hierarchical analysis of genetic structure in the habitat-specialist Eastern Sand Darter (Ammocrypta pellucida).

    PubMed

    Ginson, Robert; Walter, Ryan P; Mandrak, Nicholas E; Beneteau, Courtney L; Heath, Daniel D

    2015-02-01

    Quantifying spatial genetic structure can reveal the relative influences of contemporary and historic factors underlying localized and regional patterns of genetic diversity and gene flow - important considerations for the development of effective conservation efforts. Using 10 polymorphic microsatellite loci, we characterize genetic variation among populations across the range of the Eastern Sand Darter (Ammocrypta pellucida), a small riverine percid that is highly dependent on sandy substrate microhabitats. We tested for fine scale, regional, and historic patterns of genetic structure. As expected, significant differentiation was detected among rivers within drainages and among drainages. At finer scales, an unexpected lack of within-river genetic structure among fragmented sandy microhabitats suggests that stratified dispersal resulting from unstable sand bar habitat degradation (natural and anthropogenic) may preclude substantial genetic differentiation within rivers. Among-drainage genetic structure indicates that postglacial (14 kya) drainage connectivity continues to influence contemporary genetic structure among Eastern Sand Darter populations in southern Ontario. These results provide an unexpected contrast to other benthic riverine fish in the Great Lakes drainage and suggest that habitat-specific fishes, such as the Eastern Sand Darter, can evolve dispersal strategies that overcome fragmented and temporally unstable habitats.

  9. Hierarchical analysis of genetic structure in the habitat-specialist Eastern Sand Darter (Ammocrypta pellucida)

    PubMed Central

    Ginson, Robert; Walter, Ryan P; Mandrak, Nicholas E; Beneteau, Courtney L; Heath, Daniel D

    2015-01-01

    Quantifying spatial genetic structure can reveal the relative influences of contemporary and historic factors underlying localized and regional patterns of genetic diversity and gene flow – important considerations for the development of effective conservation efforts. Using 10 polymorphic microsatellite loci, we characterize genetic variation among populations across the range of the Eastern Sand Darter (Ammocrypta pellucida), a small riverine percid that is highly dependent on sandy substrate microhabitats. We tested for fine scale, regional, and historic patterns of genetic structure. As expected, significant differentiation was detected among rivers within drainages and among drainages. At finer scales, an unexpected lack of within-river genetic structure among fragmented sandy microhabitats suggests that stratified dispersal resulting from unstable sand bar habitat degradation (natural and anthropogenic) may preclude substantial genetic differentiation within rivers. Among-drainage genetic structure indicates that postglacial (14 kya) drainage connectivity continues to influence contemporary genetic structure among Eastern Sand Darter populations in southern Ontario. These results provide an unexpected contrast to other benthic riverine fish in the Great Lakes drainage and suggest that habitat-specific fishes, such as the Eastern Sand Darter, can evolve dispersal strategies that overcome fragmented and temporally unstable habitats. PMID:25691991

  10. Mantle Structures between Guatemala and the Eastern USArray

    NASA Astrophysics Data System (ADS)

    Chu, R.; Helmberger, D. V.; Wei, S.

    2015-12-01

    While cratons are stable features based on their ages, they apparently can be disturbed by flattened slabs and hidden hotspots. When these slabs break up they provide a host of volatiles which interact with the old lithosphere producing complicated structures. These have been imaged by a host of techniques involving modeling regional waveforms and an assortment of tomography models. Here we test these models against a deep March 25th, 2013 Guatemala event at a depth of 190 km, which produced an excellent set of TA record sections that provide dense sampling of the structure, spanning the ranges from 15 to 35 degrees. Because the structure in the southern Gulf of Mexico is uncertain, we first concentrated on deriving a pure-path model for this region. Both P and SH triplication data is well sampled by stations located in Florida from 13 degrees and beyond. The best fitting model is modified from the SH model ATL (Grand and Helmberger, 1984) with a P-model in Zhao and Helmberger (1993). These models contain a high-velocity lid structure along with a low-velocity gradient at depth. This allows the up-going S wave (direct) to remain the first arrival traveling in the fast lid to beyond 180 degrees. The modeling of the direct S along with the diving phases and depth phase triplications, pP, sP, sS allows for a well constrained model. This model ATLm and the earlier craton model CR along with mixture of the two are tested with the Cut-and-Paste (CAP) code on whole 3 component records. Over large paths of data produced by the southern US support the so-called X-phase arrivals which are produced by a 300 km transition. This feature breas down at large distance (>25 degree) along a northwest-southeast boundary. Data at larger distances indicate a complexity in the 660 transition which appears to be caused by a fast slab located at the top of the lower mantle. Variation in the EF-CD branches of pP and sP display changes of up to 5 s and sS up to 10 s, associated with the

  11. Stand and landscape level effects of a major outbreak of spruce beetles on forest vegetation in the Copper River Basin, Alaska

    USGS Publications Warehouse

    Allen, J.L.; Wesser, S.; Markon, C.J.; Winterberger, K.C.

    2006-01-01

    From 1989 to 2003, a widespread outbreak of spruce beetles (Dendroctonus rufipennis) in the Copper River Basin, Alaska, infested over 275,000 ha of forests in the region. During 1997 and 1998, we measured forest vegetation structure and composition on one hundred and thirty-six 20-m ?? 20-m plots to assess both the immediate stand and landscape level effects of the spruce beetle infestation. A photo-interpreted vegetation and infestation map was produced using color-infrared aerial photography at a scale of 1:40,000. We used linear regression to quantify the effects of the outbreak on forest structure and composition. White spruce (Picea glauca) canopy cover and basal area of medium-to-large trees [???15 cm diameter-at-breast height (1.3 m, dbh)] were reduced linearly as the number of trees attacked by spruce beetles increased. Black spruce (Picea mariana) and small diameter white spruce (<15 cm dbh) were infrequently attacked and killed by spruce beetles. This selective attack of mature white spruce reduced structural complexity of stands to earlier stages of succession and caused mixed tree species stands to lose their white spruce and become more homogeneous in overstory composition. Using the resulting regressions, we developed a transition matrix to describe changes in vegetation types under varying levels of spruce beetle infestations, and applied the model to the vegetation map. Prior to the outbreak, our study area was composed primarily of stands of mixed white and black spruce (29% of area) and pure white spruce (25%). However, the selective attack on white spruce caused many of these stands to transition to black spruce dominated stands (73% increase in area) or shrublands (26% increase in area). The post-infestation landscape was thereby composed of more even distributions of shrubland and white, black, and mixed spruce communities (17-22% of study area). Changes in the cover and composition of understory vegetation were less evident in this study

  12. Spruce budworm returns to the northeast

    Treesearch

    Lloyd Irland; William H. McWilliams

    2014-01-01

    Spruce and balsam fir supply a wealth of timber and other benefits across the northern tier of the Northeastern United States. This article is the second of a two-part series that provides an update on spruce and fir for the four Northem Forest states (Maine, New Hampshire, New York, and Vermont) using the latest Forest Inventory and Analysis (FIA) results (2012). Part...

  13. Silvical characteristics of red spruce (Picea rubens)

    Treesearch

    Arthur C. Hart

    1959-01-01

    Red spruce (Picea rubens Sarg.) is not only the most important of the spruces; it is also one of the most important of all the conifers in northeastern North America. It is a tree of many uses. The paper industry relies heavily on it for pulpwood; in the variety of its other uses it rivals white pine.

  14. Lepidoptera associated with western spruce budworm: introduction

    Treesearch

    Robert E. Stevens; V. M. Carolin; George P. Markin

    1984-01-01

    Field workers doing surveys, control operations, and research on western spruce bud worm often encounter other kinds of foliage-feeding larvae, some of which closely resemble western spruce bud worm , Workers must be able to distinguish between the different species and groups.

  15. The extent and meaning of hybridization and introgression between Siberian spruce (Picea obovata) and Norway spruce (Picea abies): cryptic refugia as stepping stones to the west?

    PubMed

    Tsuda, Yoshiaki; Chen, Jun; Stocks, Michael; Källman, Thomas; Sønstebø, Jørn Henrik; Parducci, Laura; Semerikov, Vladimir; Sperisen, Christoph; Politov, Dmitry; Ronkainen, Tiina; Väliranta, Minna; Vendramin, Giovanni Giuseppe; Tollefsrud, Mari Mette; Lascoux, Martin

    2016-06-01

    Boreal species were repeatedly exposed to ice ages and went through cycles of contraction and expansion while sister species alternated periods of contact and isolation. The resulting genetic structure is consequently complex, and demographic inferences are intrinsically challenging. The range of Norway spruce (Picea abies) and Siberian spruce (Picea obovata) covers most of northern Eurasia; yet their geographical limits and histories remain poorly understood. To delineate the hybrid zone between the two species and reconstruct their joint demographic history, we analysed variation at nuclear SSR and mitochondrial DNA in 102 and 88 populations, respectively. The dynamics of the hybrid zone was analysed with approximate Bayesian computation (ABC) followed by posterior predictive structure plot reconstruction and the presence of barriers across the range tested with estimated effective migration surfaces. To estimate the divergence time between the two species, nuclear sequences from two well-separated populations of each species were analysed with ABC. Two main barriers divide the range of the two species: one corresponds to the hybrid zone between them, and the other separates the southern and northern domains of Norway spruce. The hybrid zone is centred on the Urals, but the genetic impact of Siberian spruce extends further west. The joint distribution of mitochondrial and nuclear variation indicates an introgression of mitochondrial DNA from Norway spruce into Siberian spruce. Overall, our data reveal a demographic history where the two species interacted frequently and where migrants originating from the Urals and the West Siberian Plain recolonized northern Russia and Scandinavia using scattered refugial populations of Norway spruce as stepping stones towards the west.

  16. Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure

    USGS Publications Warehouse

    Poag, C.W.

    2005-01-01

    This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism. ?? 2005 Geological Society of America.

  17. Eastern rim of the Chesapeake Bay impact crater: Morphology, stratigraphy, and structure

    USGS Publications Warehouse

    Poag, C.W.

    2005-01-01

    This study reexamines seven reprocessed (increased vertical exaggeration) seismic reflection profiles that cross the eastern rim of the Chesapeake Bay impact crater. The eastern rim is expressed as an arcuate ridge that borders the crater in a fashion typical of the "raised" rim documented in many well preserved complex impact craters. The inner boundary of the eastern rim (rim wall) is formed by a series of raterfacing, steep scarps, 15-60 m high. In combination, these rim-wall scarps represent the footwalls of a system of crater-encircling normal faults, which are downthrown toward the crater. Outboard of the rim wall are several additional normal-fault blocks, whose bounding faults trend approximately parallel to the rim wall. The tops of the outboard fault blocks form two distinct, parallel, flat or gently sloping, terraces. The innermost terrace (Terrace 1) can be identified on each profile, but Terrace 2 is only sporadically present. The terraced fault blocks are composed mainly of nonmarine, poorly to moderately consolidated, siliciclastic sediments, belonging to the Lower Cretaceous Potomac Formation. Though the ridge-forming geometry of the eastern rim gives the appearance of a raised compressional feature, no compelling evidence of compressive forces is evident in the profiles studied. The structural mode, instead, is that of extension, with the clear dominance of normal faulting as the extensional mechanism. 

  18. Structural interpretation of seismic reflection data from eastern Salt Range and Potwar Plateau, Pakistan

    SciTech Connect

    Pennock, E.S.; Lillie, R.J.; Zaman, A.S.H.; Yousaf, M.

    1989-07-01

    Approximately 1600 km of seismic reflection profiles from the eastern Salt Range and Potwar Plateau (SR/PP) of Pakistan is integrated with available magnetostratigraphic, surface geologic, and well data to classify structural styles, determine the timing of deformation, and estimate the amount of telescoping of the sedimentary cover. The eastern SR/PP are similar to other fold-and-thrust belts underlain by evaporites in that (1) it is part of a zone of overthrusting that extends considerably farther over the Himalayan foreland than adjacent areas not underlain by evaporites, (2) the overall thrust wedge has a narrow cross-sectional taper, (3) structures verge toward the hinterland as well as toward the foreland, and (4) fold trends are long and continuous, consisting of tight salt-cored anticlines separated by broad synclines. 11 figures, 1 table.

  19. Reconstructing the landscape structure of the Lena-Angara interfluve (south part of Eastern Siberia)

    NASA Astrophysics Data System (ADS)

    Atutova, Zhanna

    2015-04-01

    Historical-geographical reconstructions of the landscape structure of territories developed in the remote past constitute the necessary element in the chain of research into the dynamics and the degree of transformation of geosystems caused by the influence of the natural regularities and anthropogenic factors. The objective of this study is to determine the specific features of the territory of the Lena-Angara interfluve in the late 19th - early 20th centuries in the interest of a subsequent different-time comparative analysis of the landscape situation. An analysis of the features inherent in the functioning of the geosystems of the Lena-Angara interfluve was made by using, as an example, an elevated plateau with the sources of the Kuda river as well as of the Ilga and Kuda rivers. The relief is represented by a tableland with narrow crests of the watersheds, heavily dissected by a dense network of the valleys of rivers. The denudation processes created planate table-shaped elevations and plateaus whose range of absolute altitudes varies between 400 and 1000 m. The analysis of the landscape structure showed that the study territory was the home for mountain-taiga dark-coniferous and deciduous classes of facies. Larch, spruce-larch and, in places, pine-larch subshrub-grass-moss forests grew within the basins of the Ilga and Kulenga rivers. The watershed spaces of the Ilga-Kuda interfluve, and also the slopes of the upper reaches of the Kuda river were occupied by Siberian stone pine and larch-spruce subshrub-moss groups of facies. In spite of the ubiquitous occurrence of taiga-forest ranges, most of them transformed to derivative groups of facies. Forest fires gave impetus to a widespread occurrence of coniferous/small-leaved complexes in burned-over areas. The study area was poorly populated at the period under investigation; therefore, cultivated lands occupied very small territories. The upper reaches of the Kulenga river included small tracts of arable land

  20. Bioecology of the conifer swift moth, Korscheltellus gracilis, a root feeder associated with spruce-fir decline

    Treesearch

    William E. Wallner; David L. Wagner; Bruce L. Parker; Donald L. Tobi

    1991-01-01

    During the past two decades, the decline of red spruce, Picea rubens Sargent, and balsam fir, Abies balsamea (L), at high elevations (900-1200 m) in eastern North America has evoked concern about the effects of anthropogenic deposition upon terrestrial ecosystems. In many high-elevation forests across New England, as many as 50...

  1. Pathogenicity Of Nosema fumiferanae (Thomson) (Microsporida) In Spruce Budworm, Choristoneura Fumiferana (Clemens), And Implications Of Diapause Conditions

    Treesearch

    Leah S. Bauer; Gerald L. Nordin

    1988-01-01

    A standardized bioassay procedure was used to determine median lethal doses (LD 50) of the microsporidium, Nosema fumiferanae (Thom.), on newly molted fourth- and fifth-instar eastern spruce budworm larvae (Choristoneura fumiferana (Clem.)). The LD50 for fifth-instar larva was 1.23 x 10...

  2. Calcium status of the forest floor in red spruce forests of the northeastern U.S. - past, present and future

    Treesearch

    Mark B. David; Gregory B. Lawrence; Walter C. Shortle; Scott W. Bailey

    1996-01-01

    Dieback and growth decline of red spruce (Picea rubens) in the eastern U.S. coincides with the period of acidic deposition, and has led to much speculation as to whether this decline is caused by decreased root-available Ca in the soil.

  3. Aerial field tests of five insecticides on western spruce budworm in Idaho and Montana, 1978-1980

    Treesearch

    George P. Markin; David R. Johnson

    1986-01-01

    Each of five insecticides was applied at two or three application rates by helicopter to 20-ha plots. Effectiveness of each application rateagainst eastern spruce budworm (Choristoneura occidentalis) was judged by comparing larval population reduction at 15 or 20 days aftertreatment against populations in untreated check plots. Performance of each...

  4. Crafting a competitive edge: white spruce regeneration in Alaska.

    Treesearch

    Jonathan. Thompson

    2005-01-01

    Over the past two decades, unprecedented levels of disturbance have occurred in the white spruce forests of Alaska. Spruce bark beetles, fires, and timber harvests have left millions of acres of dead spruce with little spruce regeneration. To assist public and private landowners, Pacific Northwest Research (PNW) Station scientists are testing various approaches to...

  5. Spruce aphid (Elatobium abietinum Walker) (Hemiptera: Aphididae) [Chapter XXIV

    Treesearch

    Ann M. Lynch

    2014-01-01

    Elatobium abietinum Walker is a spruce-feeding aphid that in Europe is referred to as the green spruce aphid (Day et al., 1998a) (Fig. 1). However, in North America E. abietinum is known simply as the spruce aphid, while the common name "green spruce aphid" refers to a different species, Cinara fornacula Hottes (Hemiptera: Aphididae) (http://www.entsoc.org/...

  6. Structural model of the eastern Achara-Trialeti fold and thrust belt using seismic reflection profiles

    NASA Astrophysics Data System (ADS)

    Alania, Victor; Chabukiani, Alexander; Enukidze, Onise; Razmadze, Alexander; Sosson, Marc; Tsereteli, Nino; Varazanashvili, Otar

    2017-04-01

    Our study focused on the structural geometry at the eastern Achara-Trialeti fold and thrust belt (ATFTB) located at the retro-wedge of the Lesser Caucasus orogen (Alania et al., 2016a). Our interpretation has integrated seismic reflection profiles, several oil-wells, and the surface geology data to reveal structural characteristics of the eastern ATFTB. Fault-related folding theories were used to seismic interpretation (Shaw et al., 2004). Seismic reflection data reveal the presence of basement structural wedge, south-vergent backthrust, north-vergent forethrust and some structural wedges (or duplex). The rocks are involved in the deformation range from Paleozoic basement rocks to Tertiary strata. Building of thick-skinned structures of eastern Achara-Trialeti was formed by basement wedges propagated from south to north along detachment horizons within the cover generating thin-skinned structures. The kinematic evolution of the south-vergent backthrust zone with respect to the northward propagating structural wedge (or duplexes). The main style of deformation within the backthrust belt is a series of fault-propagation folds. Frontal part of eastern ATFTB are represent by triangle zone (Alania et al., 2016b; Sosson et al., 2016). A detailed study was done for Tbilisi area: seismic refection profiles, serial balanced cross-sections, and earthquakes reveal the presence of an active blind thrust fault beneath Tbilisi. 2 & 3-D structural models show that 2002 Mw 4.5 Tbilisi earthquake related to a north-vergent blind thrust. Empirical relations between blind fault rupture area and magnitude suggest that these fault segments could generate earthquakes of Mw 6.5. The growth fault-propagation fold has been observed near Tbilisi in the frontal part of eastern ATFTB. Seismic reflection profile through Ormoiani syncline shows that south-vergent growth fault-propagation fold related to out-of-the-syncline thrust. The outcrop of fault-propagation fold shown the geometry of the

  7. Turbulence parameter inside and above a tall spruce site

    NASA Astrophysics Data System (ADS)

    Biermann, T.; Staudt, K.; Serafimovich, A.; Foken, T.

    2009-04-01

    In the EGER (ExchanGE processes in mountainous Regions) project, different physical, chemical and biological processes in the soil-vegetation-boundary-layer system were investigated. Field experiments were performed at the BayCEER research site Waldstein/Weidenbrunnen, a spruce site located in the Fichtelgebirge Mountains in North-Eastern Bavaria, which are challenging for their heterogeneity and orographically structured terrain. Turbulence structure, advection, flux gradients of meteorological and chemical quantities were observed within the first intensive observation period (IOP 1) in September and October 2007. Observations of turbulence structure were obtained by a vertical profile of sonic anemometers covering all parts of the forest up to the lower part of the roughness sub layer. Field observations are complemented by simulations of ACASA model (Advanced Canopy-Atmosphere-Soil Algorithm). Integral turbulence characteristics, the normalized standard deviation of a turbulent quantity, can be used to describe the structure of turbulence. A comparison between measured and predicted values shows whether turbulence is fully developed or not and is therefore used in quality assessment. For this quality control and as an input for models, when measurements are not available, parameterizations for profiles are needed. Since there is no uniform theory for those parameterizations inside a forest available, different approaches were tested with data collected during the EGER IOP1. In order to parameterize the integral turbulence characteristics of the wind components inside the roughness sub layer a dimensionless height ζ = hc L-1 should be used instead of ζ = z L-1, which is used above short vegetation. Profiles of integral turbulence characteristics from different ecosystems show that the decrease inside the roughness sub layer is similar but that parameterizations of profiles can not be generalized due to different stand structures. Selecting the profiles of the

  8. SPRUCE experiment data infrastructure development

    NASA Astrophysics Data System (ADS)

    Krassovski, Misha

    2013-04-01

    The SPRUCE experiment (http://mnspruce.ornl.gov) is the primary component of the Terrestrial Ecosystem Science Scientific Focus Area of ORNL's Climate Change Program, focused on terrestrial ecosystems and the mechanisms that underlie their responses to climatic change. The experimental work is to be conducted in a Picea mariana [black spruce] - Sphagnum spp. bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The site is located at the southern margin of the boreal peatland forest. It is an ecosystem considered especially vulnerable to climate change, and anticipated to be near its tipping point with respect to climate change. Responses to warming and interactions with increased atmospheric CO2 concentration are anticipated to have important feedbacks on the atmosphere and climate, because of the high carbon stocks harbored by such ecosystems. Both direct and indirect effects of these experimental perturbations will be analyzed to develop and refine models needed for full Earth system analyses. The Carbon Dioxide Information Analysis Center (CDIAC) at Oak Ridge National Laboratory (ORNL) provides data management support for the SPRUCE experiment including data infrastructure design, development, long-term storage and dissemination. This presentation is going to show how the whole data infrastructure was designed, discuss major problems that are common for remote observational systems and unique for this particular implementation. It will demonstrate the dataflow starting from the sensors and ending at the archiving/distribution points, discuss types of hardware and software used, and examine considerations that were used to choose them.

  9. Damage by the Sitka spruce weevil (Pissodes strobi) and growth patterns for 10 spruce species and hybrids over 26 years in the Pacific Northwest.

    Treesearch

    Russel G. Mitchell; Kenneth H. Wright; Norman E. Johnson

    1990-01-01

    Ten species and hybrids of spruce (Picea spp.) were planted and observed annually for 26 years at three coastal locations in Oregon and Washington to evaluate growth rates and susceptibility to the Sitka spruce weevil (= white pine weevil), Pissodes strobi The 10 spruce were: Sitka spruce, Norway spruce, Lutz spruce, black...

  10. Clinal Variation at Phenology-Related Genes in Spruce: Parallel Evolution in FTL2 and Gigantea?

    PubMed Central

    Chen, Jun; Tsuda, Yoshiaki; Stocks, Michael; Källman, Thomas; Xu, Nannan; Kärkkäinen, Katri; Huotari, Tea; Semerikov, Vladimir L.; Vendramin, Giovanni G.; Lascoux, Martin

    2014-01-01

    Parallel clines in different species, or in different geographical regions of the same species, are an important source of information on the genetic basis of local adaptation. We recently detected latitudinal clines in SNPs frequencies and gene expression of candidate genes for growth cessation in Scandinavian populations of Norway spruce (Picea abies). Here we test whether the same clines are also present in Siberian spruce (P. obovata), a close relative of Norway spruce with a different Quaternary history. We sequenced nine candidate genes and 27 control loci and genotyped 14 SSR loci in six populations of P. obovata located along the Yenisei river from latitude 56°N to latitude 67°N. In contrast to Scandinavian Norway spruce that both departs from the standard neutral model (SNM) and shows a clear population structure, Siberian spruce populations along the Yenisei do not depart from the SNM and are genetically unstructured. Nonetheless, as in Norway spruce, growth cessation is significantly clinal. Polymorphisms in photoperiodic (FTL2) and circadian clock (Gigantea, GI, PRR3) genes also show significant clinal variation and/or evidence of local selection. In GI, one of the variants is the same as in Norway spruce. Finally, a strong cline in gene expression is observed for FTL2, but not for GI. These results, together with recent physiological studies, confirm the key role played by FTL2 and circadian clock genes in the control of growth cessation in spruce species and suggest the presence of parallel adaptation in these two species. PMID:24814465

  11. SPRUCE: Spruce and Peatland Responses under Climatic and Environmental Change

    DOE Data Explorer

    SPRUCE is an experiment to assess the response of northern peatland ecosystems to increases in temperature and exposures to elevated atmospheric CO2 concentrations. It is the primary component of the Terrestrial Ecosystem Science Scientific Focus Area of ORNL's Climate Change Program, focused on terrestrial ecosystems and the mechanisms that underlie their responses to climatic change. The experimental work is to be conducted in a Picea mariana [black spruce] - Sphagnum spp. bog forest in northern Minnesota, 40 km north of Grand Rapids, in the USDA Forest Service Marcell Experimental Forest (MEF). The site is located at the southern margin of the boreal peatland forest. It is an ecosystem considered especially vulnerable to climate change, and anticipated to be near its tipping point with respect to climate change. Responses to warming and interactions with increased atmospheric CO2 concentration are anticipated to have important feedbacks on the atmosphere and climate, because of the high carbon stocks harbored by such ecosystems.[copied from http://mnspruce.ornl.gov/] While some data files are restricted to access by project members only, others are available for public download now, even as research is being actively conducted.

  12. N cycling in SPRUCE (Spruce Peatlands Response Under ...

    EPA Pesticide Factsheets

    Peatlands located in boreal regions make up a third of global wetland area and are expected to have the highest temperature increases in response to climate change. As climate warms, we expect peat decomposition may accelerate, altering the cycling of nitrogen. Alterations in the nitrogen cycle can have consequences on NO3, NH4 availability or pollution, and potentially increase nitrous oxide (N2O) emissions, a persistent greenhouse gas (GHG). These consequences can cascade to altering whole ecosystem functions and effecting human health.We are investigating nitrogen cycling response to elevated temperature and CO2 in a boreal peatland. Spruce and Peatland Responses Under Climate and Environmental Change (SPRUCE) project initiated soil warming in 2014 in ten peatland mesocosms (five temperature treatments from ambient (+0°C) to +9°C) and elevated CO2 in half of the mesocosms in 2016. Peat cores at three depths (acrotelm, catotelm, deep peat) were analyzed in the laboratory for denitrification, nitrification, and ammonification. We expect denitrification, nitrification, and ammonification rates to increase, and denitrification efficiency to decrease with rising temperatures- potentially contaminating water resources with NO3, NH4 and increase N2O concentrations in our atmosphere. This research will enhance the scientific understanding of how nitrogen cycling, an important functional eco-service, responds under environmental conditions including elevated CO2

  13. Seismic Velocity Structure Beneath the Eastern United States and Northern Mississippi Embayment

    NASA Astrophysics Data System (ADS)

    Chai, C.; Ammon, C. J.; Herrmann, R. B.; Mostafanejad, A.; Langston, C. A.

    2016-12-01

    The unprecedented high-quality seismic data from the EarthScope Transportable Array, the New Madrid Cooperative Seismic Network, and the Northern Embayment Lithosphere EarthScope Flex Array experiment provide us a great opportunity to investigate and compare the subsurface structure beneath the eastern U.S. and the northern Mississippi embayment with high resolution. The Mississippi embayment located in the south part of the eastern U.S. has undergone three episodes of major plate disruption and an enigmatic thermal event in the Cretaceous that modified the lithospheric structure beneath it. The northern part of the embayment hosts the New Madrid seismic zone, which was struck by three M7 or greater intraplate earthquakes in 1811-1812. Previous geophysical surveys suggest significant crustal heterogeneity and substantial velocity variations in the upper mantle beneath the seismic zone. However, the seismic structure differences between the northern embayment and the broader eastern U.S. region are poorly constrained, which undoubtedly exerts significant control on the lithospheric strain accumulation and release through earthquakes. Our goal is to determine seismic structure in both regions and compare the differences in terms of seismic speed variations. We construct subsurface seismic images using multiple types of complementary geophysical observations beneath both the eastern U.S. region and the northern embayment with a higher lateral resolution in the embayment. Specifically, we invert spatially smoothed P-wave receiver functions together with Rayleigh-wave group and phase velocities, and high-resolution gravity observations to construct robust estimates of the subsurface 3D seismic structure using a linearized inversion. Preliminary results include many first-order patterns of eastern US structure, including thick sedimentary cover beneath the coast plains, Mississippi Embayment, and Appalachian and midwestern basins, thicker crust beneath the Appalachians

  14. Mortality of spruce and fir in Maine in 1976-78 due to the spruce budworm outbreak

    Treesearch

    Donald W. Seegrist; Stanford L. Arner

    1982-01-01

    The spruce budworm population in Maine's spruce-fir forests has been at epidemic levels since the early 1970's. Spruce-fir mortality in 1976-78 is compared with predictions of what mortality would have been had the natural mortality rates remained at the levels experienced before the budworm outbreak. It appears that mortality of spruce and fir has increased...

  15. Uppermost mantle structure beneath eastern China and its surroundings from Pn and Sn tomography

    NASA Astrophysics Data System (ADS)

    Sun, Weijia; Kennett, B. L. N.

    2016-04-01

    The Pn and Sn residuals from regional events provide strong constraints on the structure and lithological characteristics of the uppermost mantle beneath eastern China and its surroundings. With the dense Chinese Digital Seismic Network in eastern China, separate Pn and Sn tomographic inversions have been exploited to obtain P and S velocities at a resolution of 2° × 2° or better. The patterns of P velocities are quite consistent with the S velocities at depth of 50 and 60 km, but the amplitude of P wave speed anomalies are a little larger than those of S wave speed. The low P wave speed, high S wave speed, and low Vp/Vs ratio beneath the northern part of Ordos Basin are related to upwelling hot material. Abrupt changes in material properties are indicated from the rapid variations in the Vp/Vs ratio.

  16. Structural and tectonic evolution of the eastern Cayman Trough (Caribbean Sea) from seismic reflection data

    SciTech Connect

    Leroy, S.; Mauffret, A.; Pubellier, M.

    1996-02-01

    The eastern Cayman Trough preserves a record of the Late Cretaceous to Paleogene Caribbean history that is largely affected by Neogene strike-slip tectonics of the current plate boundary. We conducted an analysis of seismic data within the eastern Cayman Trough, based upon single and multi-channel seismic reflection profiles collected during the Seacarib II cruise in 1987 and the Casis cruise in 1992. These data show that the basement of the eastern Cayman Trough can be divided into four domains from east to west, with distinct morphologic and sedimentary character and inferred older to younger ages: (1) a province of rifted Mesozoic continental crust exhibiting seven parallel horst blocks striking northeast-southwest; (2) a continent-ocean transition between provinces 1 and 3 that exhibits seamounts, small hills, and sedimentary basins; (3) an Eocene oceanic crust with rough basement but smoother relief than the rifted crust; basement trends are roughly north-south and oblique to the northwest trend in domain 1, and (4) the northern Jamaica slope, which forms an east-west-trending slope, with northward-dipping strata that flank the three deeper water domains of the Cayman Trough. The domains are interpreted to be the product of the Eocene east-west opening of the Cayman Trough as a pull-apart basin in a left-lateral strike-slip setting. Closure of the 1100 km of Eocene and younger oceanic crust of the Cayman Trough places the fault-block province adjacent to the Belize margin of Central America. A Neogene phase of transpression has reactivated structures in the four domains, along with on-land structures described by previous authors in Jamaica. The proximity of the eastern margin of the Cayman Trough to petroliferous, continental rocks in Central America suggests an improved possibility of hydrocarbon potential. Unfortunately, sediment thicknesses of less than 1 km probably are not conducive to hydrocarbon formation.

  17. Crustal structure beneath western and eastern Iceland from surface waves and receiver functions

    USGS Publications Warehouse

    Du, Z.; Foulger, G.R.; Julian, B.R.; Allen, R.M.; Nolet, G.; Morgan, W.J.; Bergsson, B.H.; Erlendsson, P.; Jakobsdottir, S.; Ragnarsson, S.; Stefansson, R.; Vogfjord, K.

    2002-01-01

    We determine the crustal structures beneath 14 broad-band seismic stations, deployed in western, eastern, central and southern Iceland, using surface wave dispersion curves and receiver functions. We implement a method to invert receiver functions using constraints obtained from genetic algorithm inversion of surface waves. Our final models satisfy both data sets. The thickness of the upper crust, as defined by the velocity horizon Vs = 3.7 km s-1, is fairly uniform at ???6.5-9 km beneath the Tertiary intraplate areas of western and eastern Iceland, and unusually thick at 11 km beneath station HOT22 in the far south of Iceland. The depth to the base of the lower crust, as defined by the velocity horizon Vs = 4.1 km s-1 is ???20-26 km in western Iceland and ???27-33 km in eastern Iceland. These results agree with those of explosion profiles that detect a thinner crust beneath western Iceland than beneath eastern Iceland. An earlier report of a substantial low-velocity zone beneath the Middle Volcanic Zone in the lower crust is confirmed by a similar observation beneath an additional station there. As was found in previous receiver function studies, the most reliable feature of the results is the clear division into an upper sequence that is a few kilometres thick where velocity gradients are high, and a lower, thicker sequence where velocity gradients are low. The transition to typical mantle velocities is variable, and may range from being very gradational to being relatively sharp and clear. A clear Moho, by any definition, is rarely seen, and there is thus uncertainty in estimates of the thickness of the crust in many areas. Although a great deal of seismic data are now available constraining the structures of the crust and upper mantle beneath Iceland, their geological nature is not well understood.

  18. Tectonic inversion in the Wandel Sea Basin: A new structural model of Kilen (eastern North Greenland)

    NASA Astrophysics Data System (ADS)

    Svennevig, Kristian; Guarnieri, Pierpaolo; Stemmerik, Lars

    2016-12-01

    The seminunatak Kilen in eastern North Greenland, with its complexly deformed Carboniferous-Cretaceous strata, is a key area to understand the tectonic history of the transform plate boundary between eastern North Greenland and Svalbard. Detailed 3-D geological mapping from oblique photogrammetry along with limited ground fieldwork and interpretation of previously published data forms the basis for a new structural model of Kilen. Previous structural models interpreted rhombic-shaped fault patterns as the evidence for strike-slip tectonics. These structures are here interpreted to be the result of a post-Coniacian NE-SW extension with NW-SE trending normal faults followed by later, N-S compression of presumable Paleocene-Eocene age, folding the faults passively and suggesting the presence of a basal detachment. Furthermore, two thrust sheets have been distinguished on Kilen: a lower Kilen Thrust Sheet and an upper Hondal Elv Thrust Sheet separated by a subhorizontal fault: the Central Detachment. The style of deformation and the structures described are interpreted as the result of Paleocene-Eocene N-S directed compression resulting in basin inversion with strike-slip faults only having minor status. This indicates that the Greenland margin as exposed on Kilen and the conjugate Svalbard margin in the West Spitsbergen fold-and-thrust belt are more similar than previously anticipated.

  19. Factors affecting spruce establishment and recruitment near western treeline, Alaska

    NASA Astrophysics Data System (ADS)

    Miller, A. E.; Sherriff, R.; Wilson, T. L.

    2015-12-01

    Regional warming and increases in tree growth are contributing to increased productivity near the western forest margin in Alaska. The effects of warming on seedling recruitment has received little attention, in spite of forecasted forest expansion near western treeline. Here, we used stand structure and environmental data from white spruce (Picea glauca) stands (n = 95) sampled across a longitudinal gradient to explore factors influencing white spruce growth, establishment and recruitment in southwest Alaska. Using tree-ring chronologies developed from a subset of the plots (n = 30), we estimated establishment dates and basal area increment (BAI) for trees of all age classes across a range of site conditions. We used GLMs (generalized linear models) to explore the relationship between tree growth and temperature in undisturbed, low elevation sites along the gradient, using BAI averaged over the years 1975-2000. In addition, we examined the relationship between growing degree days (GDD) and seedling establishment over the previous three decades. We used total counts of live seedlings, saplings and live and dead trees, representing four cohorts, to evaluate whether geospatial, climate, and measured plot covariates predicted abundance of the different size classes. We hypothesized that the relationship between abundance and longitude would vary by size class, and that this relationship would be mediated by growing season temperature. We found that mean BAI for trees in undisturbed, low elevation sites increased with July maximum temperature, and that the slope of the relationship with temperature changed with longitude (interaction significant with 90% confidence). White spruce establishment was positively associated with longer summers and/or greater heat accumulation, as inferred from GDD. Seedling, sapling and tree abundance were also positively correlated with temperature across the study area. The response to longitude was mixed, with smaller size classes

  20. Structurally controlled 'teleconnection' of large-scale mass wasting (Eastern Alps)

    NASA Astrophysics Data System (ADS)

    Ostermann, Marc; Sanders, Diethard

    2015-04-01

    In the Brenner Pass area (Eastern Alps) , closely ahead of the most northward outlier ('nose') of the Southern-Alpine continental indenter, abundant deep-seated gravitational slope deformations and a cluster of five post-glacial rockslides are present. The indenter of roughly triangular shape formed during Neogene collision of the Southern-Alpine basement with the Eastern-Alpine nappe stack. Compression by the indenter activated a N-S striking, roughly W-E extensional fault northward of the nose of the indenter (Brenner-normal fault; BNF), and lengthened the Eastern-Alpine edifice along a set of major strike-slip faults. These fault zones display high seismicity, and are the preferred locus of catastrophic rapid slope failures (rockslides, rock avalanches) and deep-seated gravitational slope deformations. The seismotectonic stress field, earthquake activity, and structural data all indicate that the South-Alpine indenter still - or again - exerts compression; in consequence, the northward adjacent Eastern Alps are subject mainly to extension and strike-slip. For the rockslides in the Brenner Pass area, and for the deep-seated gravitational slope deformations, the fault zones combined with high seismic activity predispose massive slope failures. Structural data and earthquakes mainly record ~W-E extension within an Eastern Alpine basement block (Oetztal-Stubai basement complex) in the hangingwall of the BNF. In the Northern Calcareous Alps NW of the Oetztal-Stubai basement complex, dextral faults provide defacement scars for large rockfalls and rockslides. Towards the West, these dextral faults merge into a NNW-SSE striking sinistral fault zone that, in turn, displays high seismic activity and is the locus of another rockslide cluster (Fern Pass cluster; Prager et al., 2008). By its kinematics dictated by the South-Alpine indenter, the relatively rigid Oetztal-Stubai basement block relays faulting and associated mass-wasting over a N-S distance of more than 60

  1. Impact of endochitinase-transformed white spruce on soil fungal communities under greenhouse conditions.

    PubMed

    Lamarche, Josyanne; Stefani, Franck O P; Séguin, Armand; Hamelin, Richard C

    2011-05-01

    Chitinase genes isolated from plants, bacteria or fungi have been widely used in genetic engineering to enhance the resistance of crops and trees to fungal pathogens. However, there are concerns about the possible effect of chitinase-transformed plants on nontarget fungi. This study aimed at evaluating the impact of endochitinase-transformed white spruce on soil fungal communities. Endochitinase-expressing white spruce and untransformed controls were transplanted in soils from two natural forests and grown for 8 months in a greenhouse. Soil fungal biomass and diversity, estimated through species richness and Shannon and Rao diversity indices, were not different between transgenic and control tree rhizospheres. The fungal phylogenetic community structure was the same in soil samples from control and transgenic white spruces after 8 months. Soil type and presence of seedlings had a much more significant impact on fungal community structure than the insertion and expression of the ech42 transgene within the white spruce genome. The results suggest that the insertion and constitutive expression of the ech42 gene in white spruce did not significantly affect soil fungal biomass, diversity and community structure. © 2011 Her Majesty the Queen in Right of Canada FEMS Microbiology Ecology © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd.

  2. Relationship between deep structure and oil-gas in the eastern Tarim Basin

    NASA Astrophysics Data System (ADS)

    Yu, Changqing; Qu, Chen; Han, Jianguang

    2017-04-01

    The Tarim Basin is a large composite superimposed basin which developed in the Presinian continental basement. It is an important area for oil and gas replacement in China. In the eastern part of Tarim Basin, the exploration and research degree is very low and less system, especially in the study of tectonic evolution and physical property change. Basing on the study of geophysics, drilling and regional geological data in this area, analysis of comprehensive geophysical, geological and geophysical analysis comparison are lunched by new methods and new technology of geophysical exploration. Fault, tectonic evolution and change of deep character in the eastern Tarim Basin are analyzed in system. Through in-depth study and understanding of the deep structure and physical changes of the eastern region, we obtain the fault characteristics in the study area and the deep structure and physical change maps to better guide the oil and gas exploration in this area. The east area is located in the eastern Tarim Basin, west from the Garr Man depression, Well Kunan 1 - Well Gucheng 4 line to the East, north to Kuruketage uplift group near Qunke 1 wells, south to Cherchen fault zone, east to Lop Nor depression, an area of about 9 * 104 square kilometres, Including the East of Garr Man sag, Yingjisu depression, Kongquehe slope, Tadong low uplift and the Lop Nor uplift, five two grade tectonic units. The east area of Tarim is belonging to Tarim plate. It changes with the evolution of the Tarim plate. The Tarim plate is closely related to the collision between the Yining - the Junggar plate, the Siberia plate and the southern Qiangtang - the central Kunlun plate. Therefore, it creates a complex tectonic pattern in the eastern Tarim basin. Earth electromagnetic, gravity, deep seismic and other geophysical data are processed by a new generation of geophysical information theory and method, including multi-scale inversion of potential field inversion (Hou and Yang, 2011), 3D

  3. 2-D modelling of the anticlinal structures and structural development of the eastern fold belt of the Bengal Basin, Bangladesh

    NASA Astrophysics Data System (ADS)

    Sikder, Arif Mohiuddin; Alam, M. Mustafa

    2003-02-01

    Structural architecture of the Bengal Basin has been strongly controlled by the collision pattern of the Indian plate with the Burma and Tibetan plates. The eastern fold belt (EFB) of the basin, comprising a series of north-south-trending curvilinear anticlines and synclines, represents a fold-and-thrust belt that constitutes the westward continuation of Arakan-Chin fold system of the Indo-Burman Ranges. The present study is mainly concerned with the 2-D modelling of the anticlinal structures in order to develop an understanding about the process-response relationships between the structural style and tectonic evolution of the eastern fold belt. The dominant fold-generating mechanism is believed to be the east-west-directed compressional force arising from oblique subduction of the Indian plate beneath the Burma plate that resulted in the growth of fault-propagation folds above a detachment or decollement at depth, giving rise to the Neogene accretionary prism complex development. A prominent feature of the region is the major east-dipping thrusts separating successive accretionary wedges. In seismic sections, evidence for several phases of compressional deformation suggests that multiphase stress conditions were responsible for the structural expression of the fold belt. Deep seismic sections reveal that the base of folding is characterized by a low-interval velocity horizon that represents a detachment separating the upper folded zone from the lower, seismically coherent, nearly unfolded zone. This detachment coincides with the undercompacted pressured shale unit, which is thought to have played an important role in the structural development of the eastern fold belt. Clay mineralogical analysis reveals the presence of a low-density shale horizon within the dense and thick shale sequence that is thought to be an undercompacted pressured shale during the geological past, and was responsible for the initiation of decollement and incipient diapirism involving thin

  4. From glacial refugia to modern populations: new assemblages of organelle genomes generated by differential cytoplasmic gene flow in transcontinental black spruce.

    PubMed

    Gérardi, Sébastien; Jaramillo-Correa, Juan P; Beaulieu, Jean; Bousquet, Jean

    2010-12-01

    Assessing species' range-wide cytoplasmic diversity provides valuable insights regarding their dispersal and adaptive potential in a changing environment. Transcontinental chloroplast (cpDNA) and mitochondrial DNA (mtDNA) population structures were compared to identify putative ancestral and new cytoplasmic genome assemblages in black spruce (Picea mariana), a North American boreal conifer. Mean within-population diversity and allelic richness for cpSSR markers were 0.80 and 4.21, respectively, and diminished westward. Population differentiation based on G(ST) was lower for cpDNA than for mtDNA (G(ST) =0.104 and 0.645, respectively) but appeared comparable when estimated using Jost differentiation index (D=0.459 and 0.537, respectively). Further analyses resulted in the delineation of at least three genetically distinct cpDNA lineages partially congruent with those inferred from mtDNA data, which roughly corresponded to western, central and eastern Canada. Additionally, the patterns of variation in Alaska for both cpDNA and mtDNA markers suggested that black spruce survived the last glacial maximum in this northern region. The range-wide comparison of the geographic extent of cytoplasmic DNA lineages revealed that extensive pollen gene flow between ancestral lineages occurred preferentially from west to east during the postglacial expansion of the species, while seed-mediated gene flow remained geographically restricted. This differential gene flow promoted intraspecific cytoplasmic capture that generated new assemblages of cpDNA and mtDNA genomes during the Holocene. Hence, black spruce postglacial colonization unexpectedly resulted in an increase in genetic diversity with possible adaptive consequences. © 2010 Blackwell Publishing Ltd.

  5. Efficacy of Chlorantraniliprole in Controlling Structural Infestations of the Eastern Subterranean Termite in the USA.

    PubMed

    Jones, Susan C; Vargo, Edward L; Keefer, T Chris; Labadie, Paul; Scherer, Clay W; Gallagher, Nicola T; Gold, Roger E

    2017-08-31

    Subterranean termites are the most economically important structural pests in the USA, and the eastern subterranean termite, Reticulitermes flavipes (Kollar) (Dictyoptera: Rhinotermitidae) is the most widely distributed species. Soil treatment with a liquid termiticide is a widely used method for controlling subterranean termites in structures. We assessed the efficacy of a nonrepellent termiticide, Altriset(®) (active ingredient: chlorantraniliprole), in controlling structural infestations of R. flavipes in Texas, North Carolina, and Ohio and determined the post-treatment fate of termite colonies in and around the structures. In all three states, microsatellite markers indicated that only one R. flavipes colony was infesting each structure. A single chlorantraniliprole treatment provided effective structural protection as there was no further evidence of termite activity in and on the majority of structures from approximately 1 month to 2 years post-treatment when the study concluded. Additionally, the treatment appeared to either severely reduce the infesting colony's footprint at monitors in the landscape or eliminate colony members from these monitors. A supplemental spot-treatment was conducted at one house each in Texas and North Carolina at 5 and 6 months post-treatment, respectively; no termites were observed thereafter in these structures and associated landscaping. The number of colonies found exclusively in the landscape (not attacking the structure) varied among the states, with the largest number of colonies in Texas (0-4) and North Carolina (0-5) as compared to 0-1 in Ohio, the most northern state.

  6. Growth strategy of Norway spruce under air elevated [CO2

    NASA Astrophysics Data System (ADS)

    Pokorny, R.; Urban, O.; Holisova, P.; Sprtova, M.; Sigut, L.; Slipkova, R.

    2012-04-01

    Plants will respond to globally increasing atmospheric CO2 concentration ([CO2]) by acclimation or adaptation at physiological and morphological levels. Considering the temporal onset, physiological responses may be categorized as short-term and morphological ones as long-term responses. The degree of plant growth responses, including cell division and cell expansion, is highly variable. It depends mainly on the specie's genetic predisposition, environment, mineral nutrition status, duration of CO2 enrichment, and/or synergetic effects of other stresses. Elevated [CO2] causes changes in tissue anatomy, quantity, size, shape and spatial orientation and can result in altered sink strength. Since, there are many experimental facilities for the investigation of elevated [CO2] effects on trees: i) closed systems or open top chambers (OTCs), ii) semi-open systems (for example glass domes with adjustable lamella windows - DAWs), and iii) free-air [CO2] enrichments (FACE); the results are still unsatisfactory due to: i) relatively short-term duration of experiments, ii) cultivation of young plants with different growth strategy comparing to old ones, iii) plant cultivation under artificial soil and weather conditions, and iv) in non-representative stand structure. In this contribution we are discussing the physiological and morphological responses of Norway spruce trees cultivated in DAWs during eight consecutive growing seasons in the context with other results from Norway spruce cultivation under air-elevated [CO2] conditions. On the level of physiological responses, we discuss the changes in the rate of CO2 assimilation, assimilation capacity, photorespiration, dark respiration, stomatal conductance, water potential and transpiration, and the sensitivity of these physiological processes to temperature. On the level of morphological responses, we discuss the changes in bud and growth phenology, needle and shoot morphology, architecture of crown and root system, wood

  7. Black spruce growth forms as a record of a changing winter environment at treeline, Quebec, Canada

    SciTech Connect

    Lavoie, C.; Payette, S. )

    1992-02-01

    The environmental conditions prevailing at treeline in subarctic Quebec have been reconstructed over the past 400 yr through a comparative analysis of tree rings and growth forms of black spruce (Picea mariana (Mill.) B.S.P.). Because black spruce growth forms are closely associated with the winter environment, they are a direct response to conditions of low temperature and windblown snow abrasion affecting living tissues at the snow-air interface. The age structure of supranival shoot populations was closely associated with periods of higher stem survival in winter most likely under snowier and windless conditions. Spruce growth on slopes and in the valley revealed periods of low tree-ring growth between 1601 and 1663 and between 1700 and 1904, respectively. A long-lasting period of low radial growth 1697 and 1939 prevailed in the hilltop site. During the 20th century, spruce height increased from 0.8 to 1.6 m on slopes and in the valley, while the basal level of abrasion from windblown snow increased from 0.1 to 0.5 m, suggesting an increasing trend towards warmer and snowier conditions. Abraded spruces growing during the Little Ice Age (1570-1880) were replaced by symmetrical trees during the 20th century. Supranival skirted and whorled spruces which dominated on the hilltop site during the 16th century reverted to infranival cushion and mat growth forms during the Little Ice Age. These stunted spruces were unable to recover during the recent warming because of their inability to catch enough drifting snow to allow vertical growth.

  8. Early Mesozoic structural evolution of the eastern West Qinling, northwest China

    NASA Astrophysics Data System (ADS)

    Wu, Guo-Li; Meng, Qing-Ren; Duan, Liang; Li, Lin

    2014-09-01

    This paper aims to reconstruct Early Mesozoic structural development of the eastern West Qinling by integrating structural and geochronologic analyses. The results show that the eastern West Qinling experienced two-phase deformations, separated by a period of tectonic quiescence. Large-scale south-directed displacement of thrust sheets in association with folding characterized the first-phase deformation in Late Triassic time, leading to the formation of the West Qinling fold-and-thrust belt that is composed primarily of Paleozoic-Triassic strata. This fold-and-thrust belt is in general south-convexing arc-shaped, with an accumulated south-directed displacement being over 100 km. The folding and thrusting ended up during the Norian of the Late Triassic Epoch and were immediately followed by widespread granite intrusions. Marked uplift and erosion occurred in the Early Jurassic, resulting in exhumation of the Late Triassic granites. Transpressional deformation took place in the eastern West Qinling in the Middle Jurassic on account of occurrences of strike-slip faulting and refolding. In the easternmost part of the West Qinling exists a Permian-Triassic turbidite wedge that is bordered by a right-slip fault on the northeast and by a left-slip fault on the south, indicating a westward movement that was accommodated by slip faulting. It is argued that collision of the North and South China blocks was responsible for formation of the West Qinling fold-and-thrust belt in the Late Triassic, whereas Middle Jurassic transgression is considered as the result of westward extrusion of Permian-Triassic turbiditic materials from the East Qinling owing to renewed intracontinental convergence between the North and South China blocks. A tectonic model is advanced for Early Mesozoic tectonic development of the West Qinling.

  9. An analytical method to assess spruce beetle impacts on white spruce resources, Kenai Peninsula, Alaska.

    Treesearch

    Willem W.S. van Hees

    1992-01-01

    Forest inventory data collected in 1987 fTom sample plots established on the Kenai Peninsula were analyzed to provide point-in-time estimates of the trend and current status of a spruce beetle infestation. Ground plots were categorized by stage of infestation. Estimates of numbers of live and dead white spruce trees, cubic-foot volume in those trees, and areal extent...

  10. Spectral evidence of early-stage spruce beetle infestation in Engelmann spruce

    Treesearch

    Adrianna C. Foster; Jonathan A. Walter; Herman H. Shugart; Jason Sibold; Jose Negron

    2017-01-01

    Spruce beetle (Dendroctonus rufipennis (Kirby)) outbreaks cause widespread mortality of Engelmann spruce (Picea engelmannii (Parry ex Engelm)) within the subalpine forests of the western United States. Early detection of infestations could allow forest managers to mitigate outbreaks or anticipate a response to tree mortality and the potential effects on ecosystem...

  11. Polyamines in embryogenic cultures of Norway spruce (Picea abies) and red spruce (Picea rubens)

    Treesearch

    Rakesh Minocha; Haarald Kvaalen; Subhash C. Minocha; Stephanie Long

    1993-01-01

    Embryogenic cultures of red spruce (Picea rubens Sarg.) and Norway spruce (Picea abies (L.) Karst.) were initiated from dissected mature zygotic embryos. The tissues were grown on either proliferation medium or maturation medium. On proliferation medium, the embryogenic tissue continued to produce early stage somatic embryos (...

  12. White Spruce Regeneration Following a Major Spruce Beetle Outbreak in Forests on the Kenai Peninsula, Alaska

    USDA-ARS?s Scientific Manuscript database

    Between 1987 and 2000, a spruce beetle (Dendroctonus rufipennis) epidemic infested 1.19 million hectares of spruce (Picea spp.) forests in Alaska, killing most of the large diameter trees. We evaluated whether these forests would recover to their pre-outbreak density, and determined the site conditi...

  13. Abundance of red spruce regeneration across spruce-hardwood ecotones at Gaudineer Knob, West Virginia

    Treesearch

    Albert E. Mayfield; Ray R. Hicks

    2010-01-01

    The abundance of red spruce (Picea rubens Sarg.) in the Central Appalachian Mountains has been drastically reduced over the past 100 to 150 years. The purpose of this study was to examine the potential for increases in the relative abundance of overstory red spruce in a Central Appalachian, high-elevation forest by measuring the abundance of red...

  14. Fertilization Affects Branching Pattern in Norway Spruce

    NASA Astrophysics Data System (ADS)

    Palmroth, S.; Stenberg, P.; Smolander, H.

    2001-12-01

    The increase in stand productivity from fertilization can be attributed to an increase in photosynthetic capacity, and a faster accumulation of leaf area index (LAI). Differences in the steady-state LAI are likely to reflect differences in PAR interception and/or conversion efficiency at shoot and leaf level. Furthermore, shoots ability to export carbohydrates to developing buds could be the mechanism responsible for light dependent branching. Within-canopy distribution of PAR and leaf area form the core in process-based models that are used to assess impacts of changes in the environment on production and resource use efficiency of forest stands. However, feedback between structure and radiation environment is not often incorporated in the models. We studied the relationships between light availability, shoot structure and branching pattern in Norway spruce (Picea abies (L.) Karst.) at a long-term fertilization experiment at Flakaliden research area in northern Sweden. Sampling of shoots was designed to cover the variation in canopy exposure within the live crown zone, where current shoots were still found. Canopy openness was used as a measure of the light availability at the shoot?s position. Our data showed that, at similar canopy openness, shoots of fertilized trees were longer and the number and total length of daughters were higher than in control trees. Fertilization increased the steady-state LAI and resulted in a deeper canopy, i.e. foliage is produced and survive at much lower light levels.

  15. Structural lineaments in the basement rocks of the central Eastern Desert, Egypt

    NASA Astrophysics Data System (ADS)

    Kamel, A. F.

    The Egyptian basement rocks outcrop in Eastern Desert, southern Sinai and southwestern Desert. The rocks belong to Precambrian and consist of igneous and metamorphic rocks which are characterized by crystalline character. Not much work has been done on the tectonics and structure of the basement rocks in Eastern Desert. The present work is a photogeological interpretation of the structural lineaments representing dykes, faults and joints in central Eastern Desert to differentiate between igneous and metamorphic rocks. The photogeological interpretation was carried out using normal aerial photographs scale 1:40 000 and photomosaics scale 50 000. The main trends of lineaments in the studied area are: E-W, ENE-WSW and WNW-ESE, constituting 58.4% of the total length and 54.5% of the total number. Correlating the structural lineaments in igneous rocks of Gebel El Bakriya locality with those in the metamorphic rocks of Gebel Abu Mireiwa shows that there is a marked difference between the two types. Lineaments in igneous rocks are elongated and widely spaced while those in metamorphic rocks are short and closely spaced. The different trends of joints in igneous rocks can be arranged as follows: WNW>E-W>NW>NNW>ENE>NE>N-S>NNE while the different trends of lineaments in metamorphic rocks can be arranged as follows: E-W>ENE>WNW>NW>NNW>NE>N-S>NNE. Comparison between the structural contour maps constructed for the total length of all lineaments and those representing joints in igneous and metamorphic rocks indicates that igneous rocks have lower density of lineaments than metamorphic rocks. The total length of all lineaments in Gebel El Bakriya amounts to 375 km, while lineaments representing joints have a total length of 150 km. In the metamorphic rocks of Gebel Abu Mireiwa, the total length of all lineaments is 425 km and those representing joints have a total length of 175 km. It was found that there is a relationship between the structural lineaments and radioactivity of

  16. Diet compositions and trophic guild structure of the eastern Chukchi Sea demersal fish community

    NASA Astrophysics Data System (ADS)

    Whitehouse, George A.; Buckley, Troy W.; Danielson, Seth L.

    2017-01-01

    Fishes are an important link in Arctic marine food webs, connecting production of lower trophic levels to apex predators. We analyzed 1773 stomach samples from 39 fish species collected during a bottom trawl survey of the eastern Chukchi Sea in the summer of 2012. We used hierarchical cluster analysis of diet dissimilarities on 21 of the most well sampled species to identify four distinct trophic guilds: gammarid amphipod consumers, benthic invertebrate generalists, fish and shrimp consumers, and zooplankton consumers. The trophic guilds reflect dominant prey types in predator diets. We used constrained analysis of principal coordinates (CAP) to determine if variation within the composite guild diets could be explained by a suite of non-diet variables. All CAP models explained a significant proportion of the variance in the diet matrices, ranging from 7% to 25% of the total variation. Explanatory variables tested included latitude, longitude, predator length, depth, and water mass. These results indicate a trophic guild structure is present amongst the demersal fish community during summer in the eastern Chukchi Sea. Regular monitoring of the food habits of the demersal fish community will be required to improve our understanding of the spatial, temporal, and interannual variation in diet composition, and to improve our ability to identify and predict the impacts of climate change and commercial development on the structure and functioning of the Chukchi Sea ecosystem.

  17. Seismotectonic characteristics of the northernmost Longitudinal Valley, eastern Taiwan: Structural development of a vanishing suture

    NASA Astrophysics Data System (ADS)

    Shyu, J. Bruce H.; Chen, Chun-Fu; Wu, Yih-Min

    2016-12-01

    The Longitudinal Valley in eastern Taiwan is generally considered as the suture of the collision between the Philippine Sea and the Eurasian plates, and has attracted numerous geologic and seismologic studies. In the northernmost part of the valley, however, constraints on how structures develop as the suture turns into the Ryukyu subduction system offshore are still very limited. Therefore, we analyzed relocated seismicity distributions and focal mechanisms of earthquake sequences, together with tectonic geomorphic investigations to further understand the seismotectonic characteristics of this area. In our seismologic observations, we found two previously unidentified reverse faults in the northernmost part of the Longitudinal Valley suture. One is an E-W striking, south-dipping reverse fault near the Liwu River fan delta, and the other is a N-S striking, east-dipping reverse fault near the eastern Central Range front. Both these structures connect with a detachment at 10 km deep, and may connect with each other to form a curved structural system. The Meilun fault, a well-known active structure that ruptured in a M7.3 earthquake in October 1951, is not seismically active in the past two decades, and may just be part of a secondary branch of the major structural system. In the northernmost part of the Longitudinal Valley suture, we propose that as the Coastal Range bedrocks subduct northward beneath the Eurasian plate with the Philippine Sea plate, the shallow sediments of the Longitudinal Valley, being a buoyant block, do not subduct, but overthrust northward and westward instead.

  18. Crustal structure beneath the eastern Nepal Himalayas and southern Tibet from receiver function analysis

    NASA Astrophysics Data System (ADS)

    Neupane, Arjun Sharma

    The Himalayas are the results of continental collision between the Indian plate and the Eurasian plate and serve as a natural site to study the physical causes and process of mountain building. The crustal structure beneath the Himalayas has been subject to numerous geophysical studies and the variation in the velocity structure across the Himalayan region suggests significant differences in the crustal structure between the southern and northern portion in that region. In this research, a P receiver function analysis has been conducted on data collected for 14 years (2000-2014) from 211 different stations in Eastern Nepal and Southern Tibet, to better understand the seismic velocity structure in the region. The stations cover a large area encompassing the south eastern plains of Nepal, Lesser and Greater Himalayas and the Southern Tibetan Plateau and provide an excellent geometry for seismic structure research. Following the rotation of the two horizontal components to the radial and transverse components and the time iterative deconvolution to obtain the receiver functions the H-K stacking method of Zhu and Kanamori(Zhu and Kanamori, 2000) has been used to convert the time domain receiver functions into H-K domain and obtain the values of crustal thickness and the ratio of the P and S wave velocities. The main trend in the receiver function analysis across the Himalaya from our study reflects the deepening of the moho from about 40 km beneath southern Nepal in the foothills of the Himalaya to about 80 km in southern Tibet. A locally steeper moho deep is obtained in the high range of Himalayas.

  19. Two-dimensional wavelet analysis of spruce budworm host basal area in the Border Lakes landscape

    Treesearch

    Patrick M. James; Brian R. Sturtevant; Phil Townsend; Pete Wolter; Marie-Josee. Fortin

    2011-01-01

    Increases in the extent and severity of spruce budworm (Choristoneura fumiferana Clem.) outbreaks over the last century are thought to be the result of changes in forest structure due to forest management. A corollary of this hypothesis is that manipulations of forest structure and composition can be used to reduce future forest vulnerability....

  20. Effect of seedbed preparation on natural reproduction of spruce and hemlock under dense shade

    Treesearch

    Grant Davis; Arthur C. Hart

    1961-01-01

    The cutting practices commonly recommended for spruce-fir stands in the Northeast involve uneven-aged management. The success of this type of management is predicated upon stand structures that have a range of size classes from seedlings to mature trees in intimate mixture. This kind of stand structure requires a continuous supply of reproduction of desirable species....

  1. A Contribution to the Understanding of the Regional Seismic Structure in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Di Luccio, F.; Thio, H.; Pino, N.

    2001-12-01

    Regional earthquakes recorded by two digital broadband stations (BGIO and KEG) located in the Eastern Mediterranean have been analyzed in order to study the seismic structure in this region. The area consists of different tectonic provinces, which complicate the modeling of the seismic wave propagation. We have modeled the Pnl arrivals using the FK-integration technique (Saikia, 1994) along different paths at the two stations, at several distances, ranging from 400 to 1500 km. Comparing the synthetics obtained by using several models compiled by other authors, we have constructed a velocity model, considering the informations deriving from group velocity distribution, in order to determine the finer structure in the analyzed paths. The model has been perturbed by trial and error until a compressional velocity profile has been found producing the shape of the observed waveforms. The crustal thickness, upper mantle P-wave velocity and 410-km discontinuity determine the shape of the observed waveform portions.

  2. The structure of the Ishtar Terra central and eastern parts and some tectonic problems of Venus

    NASA Technical Reports Server (NTRS)

    Bazilevskiy, A. T.

    1986-01-01

    Moving from the Maxwell Montes to the eastern edge of Ishtar Terra there is a gradual shift in submeridional meandering folded ranges in the western section of the area to straight intersecting disjunctive systems of connected faults and sublatitudinal shifts. These disjunctive systems evidently transform older structures; the major axis of the stresses created by them is primarily oriented sublatitudinally. Relative to younger structures, in the western they occupy a higher hypsometric position. The reason for the formation of this entire system may be a large astenospheric flow wihch rise in the region of Lakashmi Planum and Maxwell Montes and which spreads and plunges in an easterly direction, taking with it deformed blocks of the lithosphere.

  3. Mantle transition zone thinning beneath eastern Africa: Evidence for a whole-mantle superplume structure

    NASA Astrophysics Data System (ADS)

    Mulibo, Gabriel D.; Nyblade, Andrew A.

    2013-07-01

    to S conversions from the 410 and 660 km discontinuities observed in receiver function stacks reveal a mantle transition zone that is ~30-40 km thinner than the global average in a region ~200-400 km wide extending in a SW-NE direction from central Zambia, across Tanzania and into Kenya. The thinning of the transition zone indicates a ~190-300 K thermal anomaly in the same location where seismic tomography models suggest that the lower mantle African superplume structure connects to thermally perturbed upper mantle beneath eastern Africa. This finding provides compelling evidence for the existence of a continuous thermal structure extending from the core-mantle boundary to the surface associated with the African superplume.

  4. Electrical Resistivity Structure of the Arabia-Eurasia Collision Zone in Eastern Anatolia

    NASA Astrophysics Data System (ADS)

    Turkoglu, E.; Unsworth, M.; Caglar, I.; Tuncer, V.; Avsar, U.; Tank, B.; Turkoglu, E.; Demir, T.; Sener, A.

    2005-12-01

    The tectonics of eastern Anatolia is dominated by the collision of the Arabian and Eurasian plates. Recent passive seismic exploration has provided new constraints on the seismic velocity structure of this region and suggest that asthenosphere may be present at shallow depth within the collision zone. Magnetotelluric data can provide independent constraints on processes in regions of active tectonics by remotely sensing the electrical resistivity of the crust and upper mantle. From May to November 2005 magnetotelluric (MT) data were collected in Eastern Anatolia in a joint Canadian-Turkish project by the University of Alberta and Istanbul Technical University. Long period MT data give penetration to upper mantle depths and were collected on profiles extending from the Arabian plate to the Black Sea with a spacing of 10-15 km. More detailed broadband MT data were collected on shorter profiles crossing the North and East Anatolian Fault Zones with a spacing of 1-2 km. Preliminary resistivity models will be presented for each of the profiles and indicate that: (1) A mid-crustal conductor is present beneath the Anatolian Block in the vicinity of Elazig and terminates directly beneath the surface trace of the East Anatolian Fault. This geometry is very similar to that observed on major strike-slip faults in Northern and Eastern Tibet. (2)East of the Karliova triple junction, the Anatolian crust has a high resistivity. A low resistivity zone is present at depths of 40-50 km and may represent a shallow asthenosphere. (3)Low resistivity is observed in the upper mantle beneath Karacadag, a center of recent basaltic eruptions on the Arabian Plate, and in the crust beneath the Nemrut Golu - Suphan Dagi volcanic belt. The tectonic significance of these new MT data will be discussed in the context of other geological and geophysical data.

  5. 9. LOOKING NORTH ON SPRUCE STREET, SHOWING MILLWRIGHT SHOP, FITTING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. LOOKING NORTH ON SPRUCE STREET, SHOWING MILLWRIGHT SHOP, FITTING SHOP, ADMINISTRATION BUILDING AND ERECTING SHOP - UNION WORKS IN BACKGROUND. - Rogers Locomotive & Machine Works, Spruce & Market Streets, Paterson, Passaic County, NJ

  6. Structure, Kinematics, and Thermal/Erosion History of the eastern Central Range, Taiwan

    NASA Astrophysics Data System (ADS)

    Yeh, E.; Fisher, D. M.; Willett, S. D.; Greenan, S. L.

    2001-12-01

    Analyses of structure, incremental strain histories, and thermochronometry in the eastern Central Range of Taiwan provide insights into the kinematics within the metamorphic core of the Taiwan arc-continent collision. The results of these analyses are consistent with a three-dimensional displacement field that is fixed relative to the geometry of a thin-skinned double-sided wedge. The obliquity between the Luzon arc and the Asian passive margin results in a collision that propagates southward through time, and this time-space equivalence allows north to south variations in structural and thermal history to be evaluated in the context of mountain belt evolution. There are three general structural events in the eastern Central Range of Taiwan. D1 involves west-vergent folding and development of a slaty cleavage/schistosity with growth of fibrous overgrowths and ellipsoidal chlorite-mica aggregates. D2 is represented by east-vergent folds that deform the earlier fabrics and are associated with crenulation cleavages. D3 is defined by brittle normal faults that crosscut all the earlier fabrics. Strain analyses indicate 270 to 880 percentages of extension parallel to the mountain belt during D1. D1 strain histories, after restoring the rotations associated with D2 east-vergent folding, depict west-vergent thrusting followed by left-lateral shearing. This temporal variation in extension direction and shear direction from down-dip to along-strike is similar to the observed west-to-east variation in the orientation of the D1 stretching lineation across the Central Range. This observation, coupled with the reversal in vergence of structures from west-vergent during D1 to east-vergent during D2, indicates that the rocks of the Asian passive margin have advected from west to east relative to a displacement field that is fixed relative to the mountain belt topography. The consistency in D1 strain histories from south to north indicates that all the rocks of the eastern Central

  7. Origin and demographic history of the endemic Taiwan spruce (Picea morrisonicola)

    PubMed Central

    Bodare, Sofia; Stocks, Michael; Yang, Jeng-Chuann; Lascoux, Martin

    2013-01-01

    Taiwan spruce (Picea morrisonicola) is a vulnerable conifer species endemic to the island of Taiwan. A warming climate and competition from subtropical tree species has limited the range of Taiwan spruce to the higher altitudes of the island. Using seeds sampled from an area in the central mountain range of Taiwan, 15 nuclear loci were sequenced in order to measure genetic variation and to assess the long-term genetic stability of the species. Genetic diversity is low and comparable to other spruce species with limited ranges such as Picea breweriana, Picea chihuahuana, and Picea schrenkiana. Importantly, analysis using approximate Bayesian computation (ABC) provides evidence for a drastic decline in the effective population size approximately 0.3–0.5 million years ago (mya). We used simulations to show that this is unlikely to be a false-positive result due to the limited sample used here. To investigate the phylogenetic origin of Taiwan spruce, additional sequencing was performed in the Chinese spruce Picea wilsonii and combined with previously published data for three other mainland China species, Picea purpurea, Picea likiangensis, and P. schrenkiana. Analysis of population structure revealed that P. morrisonicola clusters most closely with P. wilsonii, and coalescent analyses using the program MIMAR dated the split to 4–8 mya, coincidental to the formation of Taiwan. Considering the population decrease that occurred after the split, however, led to a much more recent origin. PMID:24223271

  8. Phylogeography of spruce beetles (Dendroctonus rufipennis Kirby) (Curculionidae: Scolytinae) in North America.

    PubMed

    Maroja, Luana S; Bogdanowicz, Steven M; Wallin, Kimberly F; Raffa, Kenneth F; Harrison, Richard G

    2007-06-01

    Tree-feeding insects that are widespread in north temperate regions are excellent models for studying how past glaciations have impacted differentiation and speciation. We used mitochondrial DNA (mtDNA) sequences and allele frequencies at nine microsatellite loci to examine genetic population structure across the current range of the spruce beetle (Dendroctonus rufipennis), an economically important insect in North America. Two major haplotype groups occur across northern North America, from Newfoundland to Alaska, on white spruce (Picea glauca), and a third distinctive haplotype group occurs throughout the Rocky Mountains on Engelmann spruce (Picea engelmannii). The two mtDNA lineages found in northern populations are 3-4% divergent from each other and from the lineages found in the Rocky Mountains. Analyses of microsatellite data also suggest the existence of major population groupings associated with different geographical regions. In the Pacific Northwest, concordant contact zones for genetically distinct populations of spruce beetles and their principal hosts appear to reflect recent secondary contact. Although we could detect no evidence of historical mtDNA gene flow between allopatric population groups, patterns of variation in the Pacific Northwest suggest recent hybridization and introgression. Together with the pollen record for spruce, they also suggest that beetles have spread from at least three glacial refugia. A minimum estimate of divergence time between the Rocky Mountain and northern populations was 1.7 Myr (million years), presumably reflecting the combined effects of isolation during multiple glacial cycles.

  9. Microbial communities in the litter of middle taiga bilberry-spruce forests

    NASA Astrophysics Data System (ADS)

    Sizonenko, T. A.; Zagirova, S. V.; Khabibullina, F. M.

    2010-10-01

    The structure of the microbial communities in the litters of middle-taiga bilberry-spruce forests was studied. It was found that ammonifying and oligonitrophilic microorganisms predominate in these communities. Two maximums in the population density of the microorganisms were observed in June and August. The number of microorganisms increased in the direction from the spruce trunks to the periphery of the crowns. The species composition of the micromycetes in the litters under the spruce crowns and within the intercrown spaces differed. The maximum population density of the fungi was found in the litter under the periphery of the spruce crowns, whereas the maximum diversity of the micromycetes was observed within the intercrown spaces. The Trichoderma, Trichosporiella, Penicillium, Paecilomyces, and Chaetomium genera were most abundant in the litters of the bilberry spruce forests. The Penicillium genus had the maximum abundance during the entire growing period, and the amount of Mycelia sterilia increased in the fall. The maximum diversity of the fungi was observed in May and June.

  10. Origin and demographic history of the endemic Taiwan spruce (Picea morrisonicola).

    PubMed

    Bodare, Sofia; Stocks, Michael; Yang, Jeng-Chuann; Lascoux, Martin

    2013-09-01

    Taiwan spruce (Picea morrisonicola) is a vulnerable conifer species endemic to the island of Taiwan. A warming climate and competition from subtropical tree species has limited the range of Taiwan spruce to the higher altitudes of the island. Using seeds sampled from an area in the central mountain range of Taiwan, 15 nuclear loci were sequenced in order to measure genetic variation and to assess the long-term genetic stability of the species. Genetic diversity is low and comparable to other spruce species with limited ranges such as Picea breweriana, Picea chihuahuana, and Picea schrenkiana. Importantly, analysis using approximate Bayesian computation (ABC) provides evidence for a drastic decline in the effective population size approximately 0.3-0.5 million years ago (mya). We used simulations to show that this is unlikely to be a false-positive result due to the limited sample used here. To investigate the phylogenetic origin of Taiwan spruce, additional sequencing was performed in the Chinese spruce Picea wilsonii and combined with previously published data for three other mainland China species, Picea purpurea, Picea likiangensis, and P. schrenkiana. Analysis of population structure revealed that P. morrisonicola clusters most closely with P. wilsonii, and coalescent analyses using the program MIMAR dated the split to 4-8 mya, coincidental to the formation of Taiwan. Considering the population decrease that occurred after the split, however, led to a much more recent origin.

  11. Tectonic Structures offshore Trabzon-Rize Area in the Eastern Black Sea

    NASA Astrophysics Data System (ADS)

    Gündüz, Sermet; Okay, Seda; Çifçi, Günay; Dondurur, Derman; Kim, Dae-Choul; Bae, Sung-Ho

    2015-04-01

    Black Sea has attracted many researchers's attention due to the historical formation and geological structure and these are still under discussion. However general view suggest that Black Sea is a back arc basin model formed behind the Pontid volcanic arc. Even though there are many studies conducted by both Turkish and international researches and petroleum company, there are still unresolved scientific questions. To better understand the regional geology and investigate the geological formations and fault systems existing in the region, approximately 1700 km high resolution multi-channel seismic reflection data were collected in the Eastern Black Sea (around Rize and Trabzon) in 2010. This study was carried out within the scope of cooperation between Dokuz Eylul University Marine Science and Technology and Pukyong National University (PKNU). Collected lines include the continental slope and deep basin. After the data was processed by the data processing program, geological structures like slip structures, turbidity and sediment waves has attracted attention commonly seen in the Black Sea region. Location of the faults that exist in the region, their extension and characteristics were also investigated. Although the basin shows opening feature during the formation, many fold structures caused by compression structure was also observed around the continental slope. East-west trending fold belt observed by interpretation of the seismic lines was associated with Trabzon fault which is thought to exist in the region. In addition to these, mud volcanoes and volcanic dome structures were also observed in the study area.

  12. Influence of Mesozoic age structure on Miocene tectonic development in NE Anzoategui, Eastern Venezuela Basin

    SciTech Connect

    Sadler, P.; White, S.

    1996-08-01

    Structure within and surrounding the Quiamare-La Ceiba region, Eastern Venezuela Basin, is dominated by two major thrust fault systems. They were generated during Early-Middle Miocene time in response to oblique convergence of the Caribbean and South American plates. They are. respectively, the SE vergent NE-SW oriented Anaco fault system, and the SSE vergent ENE-WSW oriented Pirital fault system. The major structural feature associated with each fault system is a basement cored ramp anticline. New seismic data provides evidence that contributes to a better understanding of the sequence of tectonic development within and surrounding the Quiamare-La Ceiba region. Compressional structures in both the hanging wall and the footwall of the Pirital fault system appear to be inverted normal faults, that were previously active during Mesozoic time along the northern South America passive margin. A conjugate set of strike-slip faults is also present. They are oriented NNW-SSE, parallel to the Urica lineation, and SSW-NNE, respectively. A Mesozoic origin for these faults is suggested. Post-compressional relaxation during Plio-Pleistocene time resulted in the development of shallow, small scale normal faults. These normal faults appear to be localized by structural adjustments along the strike-slip fault sets. Existing oil and gas production within the Quiamare-La Ceiba region is from localized structural closures. Strike-slip faults dissect the prevailing structural grain, and may provide an additional hydrocarbon trapping mechanism.

  13. Structural and thermochronological evidence for Paleogene basement-involved shortening in the axial Eastern Cordillera, Colombia

    NASA Astrophysics Data System (ADS)

    Saylor, Joel E.; Horton, Brian K.; Stockli, Daniel F.; Mora, Andrés; Corredor, Jaime

    2012-11-01

    Although most recent studies regard the northern Andes primarily as a low-shortening inversion orogen, new mapping and thermochronology along the paired basement-involved Floresta massif and Floresta basin in the axial Eastern Cordillera of Colombia suggest major Paleogene shortening in a ramp-flat fold-thrust belt. Field mapping indicates that the hanging wall of the east-directed Soápaga fault system contains a series of upright thrust sheets with flat-on-flat cutoff relationships and a deformed footwall characterized by a complex triangle zone. These geometries necessitate roughly east-west shortening exceeding that of a previously mapped overturned hanging wall anticline and disharmonic footwall folds. Zircon (U-Th)/He (ZHe) ages indicate exhumation-induced cooling of the Soápaga hanging wall through the ˜180 °C closure temperature at 31-25 Ma. This cooling postdated documented shortening to the west and predated shortening to the east, suggesting an eastward progression of Paleogene deformation. Synorogenic Oligocene footwall strata of the Floresta basin contain distal fine-grained sediments and lack growth strata or Oligocene detrital ZHe ages, suggesting relatively high heave along the Soápaga fault system. These results are consistent with a rapidly eastward-propagating, basement-involved fold-thrust belt with ramp-flat structures that accommodated tens of km of shortening. Long-term stasis of the deformation front on the eastern and western flanks of the Eastern Cordillera due to localization of Neogene shortening along Mesozoic rift-bounding normal faults indicates a shift in deformational style in late Oligocene-early Miocene time. This geometric and temporal framework implies: 1) a total shortening in the northern Andes exceeding most current estimates; 2) Paleogene deformation in the Eastern Cordillera marked by rapid advances of the deformation front along a ramp-flat thrust system; and 3) focused Neogene reactivation (inversion) of master rift

  14. Patterns of Population Structure for Inshore Bottlenose Dolphins along the Eastern United States

    PubMed Central

    2013-01-01

    Globally distributed, the bottlenose dolphin (Tursiops truncatus) is found in a range of offshore and coastal habitats. Using 15 microsatellite loci and mtDNA control region sequences, we investigated patterns of genetic differentiation among putative populations along the eastern US shoreline (the Indian River Lagoon, Florida, and Charleston Harbor, South Carolina) (microsatellite analyses: n = 125, mtDNA analyses: n = 132). We further utilized the mtDNA to compare these populations with those from the Northwest Atlantic, Gulf of Mexico, and Caribbean. Results showed strong differentiation among inshore, alongshore, and offshore habitats (ФST = 0.744). In addition, Bayesian clustering analyses revealed the presence of 2 genetic clusters (populations) within the 250 km Indian River Lagoon. Habitat heterogeneity is likely an important force diversifying bottlenose dolphin populations through its influence on social behavior and foraging strategy. We propose that the spatial pattern of genetic variation within the lagoon reflects both its steep longitudinal transition of climate and also its historical discontinuity and recent connection as part of Intracoastal Waterway development. These findings have important management implications as they emphasize the role of habitat and the consequence of its modification in shaping bottlenose dolphin population structure and highlight the possibility of multiple management units existing in discrete inshore habitats along the entire eastern US shoreline. PMID:24129993

  15. Patterns of population structure for inshore bottlenose dolphins along the eastern United States.

    PubMed

    Richards, Vincent P; Greig, Thomas W; Fair, Patricia A; McCulloch, Stephen D; Politz, Christine; Natoli, Ada; Driscoll, Carlos A; Hoelzel, A Rus; David, Victor; Bossart, Gregory D; Lopez, Jose V

    2013-01-01

    Globally distributed, the bottlenose dolphin (Tursiops truncatus) is found in a range of offshore and coastal habitats. Using 15 microsatellite loci and mtDNA control region sequences, we investigated patterns of genetic differentiation among putative populations along the eastern US shoreline (the Indian River Lagoon, Florida, and Charleston Harbor, South Carolina) (microsatellite analyses: n = 125, mtDNA analyses: n = 132). We further utilized the mtDNA to compare these populations with those from the Northwest Atlantic, Gulf of Mexico, and Caribbean. Results showed strong differentiation among inshore, alongshore, and offshore habitats (ФST = 0.744). In addition, Bayesian clustering analyses revealed the presence of 2 genetic clusters (populations) within the 250 km Indian River Lagoon. Habitat heterogeneity is likely an important force diversifying bottlenose dolphin populations through its influence on social behavior and foraging strategy. We propose that the spatial pattern of genetic variation within the lagoon reflects both its steep longitudinal transition of climate and also its historical discontinuity and recent connection as part of Intracoastal Waterway development. These findings have important management implications as they emphasize the role of habitat and the consequence of its modification in shaping bottlenose dolphin population structure and highlight the possibility of multiple management units existing in discrete inshore habitats along the entire eastern US shoreline.

  16. Growth of white pine and red spruce trees after pruning

    Treesearch

    Grant Davis

    1958-01-01

    Are pines the only coniferous trees suitable for pruning in the Northeast, or is it feasible to prune red spruce as well? Although red spruce is an important lumber species in the spruce-fir region, it is seldom pruned because of its relatively slow rate of growth.

  17. Aluminum-induced calcium deficiency syndrome in declining red spruce

    Treesearch

    Walter C. Shortle; Kevin T. Smith

    1988-01-01

    Prolonged suppression of cambial growth has apparently caused a decline in radial growth in many mature red spruce, Picea rubens. Surveys indicate that this decline occurs in trees throughout the natural range of red spruce and is independent of elevation, tree size, and age class. In addition, crowns of mature red spruce at high elevations across...

  18. History of the spruce-fir forest in the Catskill Mountains of New York.

    PubMed

    Kudish, Michael

    2013-09-01

    Red spruce (Picea rubens Sarg.) and balsam fir (Abies balsamea (L.) Mill.) were present by 13,700 years B.C.E. in the Catskills Mountains of southeastern New York State. These conifers were, and still are, largely confined to the eastern and far western portions of the region. A gap in the distribution exists between these populations. Both species are absent from the intervening East Branch Delaware River watershed. No red spruce macrofossils were found in this watershed, suggesting that this conifer never colonized the gap postglacially. Rare macrofossils of balsam fir were found in only three of the 24 peatlands in this watershed, the conifer having disappeared between 11,300 and 8,200 years B.C.E. © 2013 New York Academy of Sciences.

  19. Climate-mediated changes in zooplankton community structure for the eastern Bering Sea

    NASA Astrophysics Data System (ADS)

    Eisner, Lisa B.; Napp, Jeffrey M.; Mier, Kathryn L.; Pinchuk, Alexei I.; Andrews, Alexander G.

    2014-11-01

    Zooplankton are critical to energy transfer between higher and lower trophic levels in the eastern Bering Sea ecosystem. Previous studies from the southeastern Bering Sea shelf documented substantial differences in zooplankton taxa in the Middle and Inner Shelf Domains between warm and cold years. Our investigation expands this analysis into the northern Bering Sea and the south Outer Domain, looking at zooplankton community structure during a period of climate-mediated, large-scale change. Elevated air temperatures in the early 2000s resulted in regional warming and low sea-ice extent in the southern shelf whereas the late 2000s were characterized by cold winters, extensive spring sea ice, and a well-developed pool of cold water over the entire Middle Domain. The abundance of large zooplankton taxa such as Calanus spp. (C. marshallae and C. glacialis), and Parasagitta elegans, increased from warm to cold periods, while the abundance of gelatinous zooplankton (Cnidaria) and small taxa decreased. Biomass followed the same trends as abundance, except that the biomass of small taxa in the southeastern Bering Sea remained constant due to changes in abundance of small copepod taxa (increases in Acartia spp. and Pseudocalanus spp. and decreases in Oithona spp.). Statistically significant changes in zooplankton community structure and individual species were greatest in the Middle Domain, but were evident in all shelf domains, and in both the northern and southern portions of the eastern shelf. Changes in community structure did not occur abruptly during the transition from warm to cold, but seemed to begin gradually and build as the influence of the sea ice and cold water temperatures persisted. The change occurred one year earlier in the northern than the southern Middle Shelf. These and previous observations demonstrate that lower trophic levels within the eastern Bering Sea respond to climate-mediated changes on a variety of time scales, including those shorter than

  20. Shallow crustal structure of eastern-central Trans-Mexican Volcanic Belt.

    NASA Astrophysics Data System (ADS)

    Campos-Enriquez, J. O.; Ramón, V. M.; Lermo-Samaniego, J.

    2015-12-01

    Central-eastern Trans-Mexican Volcanic Belt (TMVB) is featured by large basins (i.e., Toluca, Mexico, Puebla-Tlaxcala, Libres-Oriental). It has been supposed that major crustal faults limit these basins. Sierra de Las Cruces range separates the Toluca and Mexico basins. The Sierra Nevada range separates Mexico basin from the Puebla-Tlaxcala basin. Based in gravity and seismic data we inferred the Toluca basin is constituted by the Ixtlahuaca sub-basin, to the north, and the Toluca sub-basin to the south, which are separated by a relative structural high. The Toluca depression is more symmetric and bounded by sub-vertical faults. In particular its eastern master fault controlled the emplacement of Sierra de Las Cruces range. Easternmost Acambay graben constitutes the northern and deepest part of the Ixtlahuaca depression. The Toluca-Ixtlahuaca basin is inside the Taxco-San Miguel de Allende fault system, and limited to the west by the Guerrero terrane which continues beneath the TMVB up to the Acambay graben. Mexico basin basement occupies an intermediate position and featured by a relative structural high to the north-east, as established by previous studies. This relative structural high is limited to the west by the north-south Mixhuca trough, while to the south it is bounded by the east-west Copilco-Xochimilco-Chalco sub-basin. The Puebla-Tlaxcala basin basement is the shallowest of these 3 tectonic depressions. In general, features (i.e., depth) and relationship between these basins, from west to east, are controlled by the regional behavior of the Sierra Madre Oriental fold and thrust belt basement (i.e., Oaxaca Complex?). This study indicates that an active east-west regional fault system limits to the south the TMVB (from the Nevado de Toluca volcano through the Popocatepetl volcano and eastward along southern Puebla-Tlaxcala basin). The Tenango and La Pera fault systems constituting the western part of this regional fault system coincide with northern

  1. Lenticular stretch structures in eastern Nevada - possible trapping mechanism in supposed graben

    SciTech Connect

    Walker, C.T.; Dennis, J.G.; Lumsden, W.W.

    1986-04-01

    Eastern Nevada is widely recognized as a region of tectonic extension. The dominant structures are generally agreed to be low-dipping, younger over older faults and steeper listric faults that are responsible for the basins (grabens) and ranges (horsts). In the Schell Creek-Duck Creek Range, east of Ely, and in the White Pine Range, southwest of Ely, small lenticular structures bounded by tectonic discontinuities can be clearly seen in the field. These lenticular units, or stretch structures, range in length from a few meters to more than 200 m. All lenticular stretch structures that can be clearly seen in the field are stratigraphically restricted; the stretched formations are the Eureka Quartzite, the Pilot Shale, the Joana Limestone, and the Chainman Shale. Still larger stretch structures, which may include several formations, are inferred, and the authors suggest that extension has created lenticular structures at all scales. The Duck Creek and Schell Creek Ranges east of Ely consist mostly of Devonian and older rocks. They are separated by a topographically lower area containing mostly Mississippian and Pennsylvanian rocks. This structure, which separates the ranges, has been referred to as a graben, but field evidence suggests that it is a large-scale lenticular stretch structure. Unlike a true graben, the structure does not extend downward. For example, in several places within the supposed graben, Cambrian and Ordovician rocks project through a cover of Carboniferous Chainman Shale and Ely Limestone, suggesting the Chainman-Ely is a thin sheet underlain by Cambrian-Ordovician rocks. Accordingly, they suggest that extension in the Duck Creek-Schell Creek Ranges stretched the formations into lenticular bodies. Between the Duck Creek and Schell Creek Ranges, the Cambrian-Ordovician is attenuated, and the resulting tectonic depression is occupied by a lenticular mass of Carboniferous rocks.

  2. Old lower stem bark lesions apparently caused by unsuccessful spruce beetle attacks still evident on live spruce trees years later

    Treesearch

    John S. Hard; Ken P. Zogas

    2010-01-01

    We examined old bark lesions on Lutz spruce in young stands on the Kenai Peninsula, Alaska, to determine their cause. Distribution of these lesions along lower stems was similar to the distribution of spruce beetle attacks during epidemics. These lesions apparently resulted from unsuccessful attacks by spruce beetles during the late 1980s and early 1990s and appear to...

  3. Effect of increasing temperatures on the distribution of spruce beetle in Engelmann spruce forests of the Interior West, USA

    Treesearch

    R. Justin DeRose; Barbara J. Bentz; James N. Long; John D. Shaw

    2013-01-01

    The spruce beetle (Dendoctronus rufipennis) is a pervasive bark beetle indigenous to spruce (Picea spp.) forests of North America. In the last two decades outbreaks of spruce beetle have increased in severity and extent. Increasing temperatures have been implicated as they directly control beetle populations, potentially inciting endemic populations to build to...

  4. Structure of the lithosphere beneath the Eastern Alps (southern sector of the TRANSALP transect)

    NASA Astrophysics Data System (ADS)

    Castellarin, Alberto; Nicolich, Rinaldo; Fantoni, Roberto; Cantelli, Luigi; Sella, Mattia; Selli, Luigi

    2006-02-01

    supported by any significant uplifting of the Dolomites. The total average uplift of the Dolomites during the Neogene appears to be 6-7 times smaller than that recognized in the TW. Markedly the northward dip of the PL, reaching a depth of approximately 20 km, is proposed in our interpretation; finally, the Adriatic upper crustal evolution points to the late post-collision change in the tectonic grow-up of the Eastern Alps orogenic chain. The tectonic accretion of the northern frontal zone of the Eastern and Central Alps was interrupted from the Late Miocene (Serravallian-Tortonian) onward, as documented by the Molasse basin evolution. On the contrary, the structural nucleation along the S-vergent tectonic belt of the eastern Southern Alps ( Montello-Friuli thrust belt) severely continued during the Messinian and the Plio-Pleistocene. This structural evolution can be considered to be consistent with the deep under-thrusting and wedge indentation of the Adriatic lithosphere underneath the southern side of the Eastern Alps thrust-and-fold belt. Similarly, the significance of the magmatic activity for the construction of the Southern Alps crust and for its mechanical and geological differentiation, which qualified the evolution of the thrust-and-fold belt, is highlighted, starting with the Permian-Triassic magmatism and progressing with the Paleogene occurrences along the Periadriatic Lineament and in the Venetian Magmatic Province (Lessini-Euganei Hills).

  5. Seismic imaging of shallow reflectors in the eastern Kapuskasing structural zone, with correction of crossdip attitudes

    NASA Astrophysics Data System (ADS)

    Kim, Jisoo; Moon, Wooil M.; Percival, John A.; West, F. G.

    1992-10-01

    Cascaded processes of crossdip correction and residual statics are tested and applied in the reprocessing of regional data from LITHOPROBE Kapuskasing Transect line 2. The objective was to improve seismic imaging of shallow, gently dipping reflectors in the eastern Kapuskasing structural zone, a thrusted slice of Archean middle to lower crust. This focusing strategy proved to be very effective in improving the image of the reflected energy and in identifying a set of conformally dipping reflectors whose true crossdip is estimated to be approximately 17 deg NW. The estimated crossdip for a reflective, compositionally layered zone and for the basal thrust, the Ivanhoe Lake Fault zone, support the previously estimated average dip of 15-20 deg.

  6. Crustal structure across the eastern North American margin from ambient noise tomography

    NASA Astrophysics Data System (ADS)

    Lynner, Colton; Porritt, Robert W.

    2017-07-01

    Passive tectonic margins, like the eastern North American margin (ENAM), represent the meeting of oceanic and continental material where no active deformation is occurring. The recent ENAM Community Seismic Experiment provides an opportunity to examine the crustal structure across the ENAM owing to the simultaneous deployment of offshore and onshore seismic instrumentation. Using Rayleigh wave phase and group velocities derived from ambient noise data, we invert for shear velocity across the ENAM. We observe a region of transitional crustal thicknesses that connects the oceanic and continental crusts. Associated with the transitional crust is a localized positive gravitational anomaly. Farther east, the East Coast magnetic anomaly (ECMA) is located at the intersection of the transitional and oceanic crusts. We propose that underplating of dense magmatic material along the bottom of the transitional crust is responsible for the gravitational anomaly and that the ECMA demarks the location of initial oceanic crustal formation.

  7. Four New Sulfated Polar Steroids from the Far Eastern Starfish Leptasterias ochotensis: Structures and Activities

    PubMed Central

    Malyarenko, Timofey V.; Malyarenko (Vishchuk), Olesya S.; Ivanchina, Natalia V.; Kalinovsky, Anatoly I.; Popov, Roman S.; Kicha, Alla A.

    2015-01-01

    Three new sulfated steroid monoglycosides, leptaochotensosides A–C (1–3), and a new sulfated polyhydroxylated steroid (4) were isolated from the alcoholic extract of the Far Eastern starfish Leptasterias ochotensis. The structures of compounds 1–4 were established by extensive nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESIMS) analyses and chemical transformations. Although the isolated compounds did not show any apparent cytotoxicity against melanoma RPMI-7951 and breast cancer T-47D cell lines, leptaochotensoside A (1) demonstrated inhibition of T-47D cell colony formation in a soft agar clonogenic assay at nontoxic doses. In addition, this compound decreased the epidermal growth factor (EGF)-induced colony formation of mouse epidermal JB6 Cl41 cells. The cancer preventive action of 1 is realized through regulation of mitogen-activated protein kinase (MAPK) signaling pathway. PMID:26193286

  8. Four New Sulfated Polar Steroids from the Far Eastern Starfish Leptasterias ochotensis: Structures and Activities.

    PubMed

    Malyarenko, Timofey V; Malyarenko Vishchuk, Olesya S; Ivanchina, Natalia V; Kalinovsky, Anatoly I; Popov, Roman S; Kicha, Alla A

    2015-07-16

    Three new sulfated steroid monoglycosides, leptaochotensosides A-C (1-3), and a new sulfated polyhydroxylated steroid (4) were isolated from the alcoholic extract of the Far Eastern starfish Leptasterias ochotensis. The structures of compounds 1-4 were established by extensive nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESIMS) analyses and chemical transformations. Although the isolated compounds did not show any apparent cytotoxicity against melanoma RPMI-7951 and breast cancer T-47D cell lines, leptaochotensoside A (1) demonstrated inhibition of T-47D cell colony formation in a soft agar clonogenic assay at nontoxic doses. In addition, this compound decreased the epidermal growth factor (EGF)-induced colony formation of mouse epidermal JB6 Cl41 cells. The cancer preventive action of 1 is realized through regulation of mitogen-activated protein kinase (MAPK) signaling pathway.

  9. Monitoring larval populations of the Douglas-fir tussock moth and the western spruce budworm on permanent plots: sampling methods and statistical properties of data

    Treesearch

    A.R. Mason; H.G. Paul

    1994-01-01

    Procedures for monitoring larval populations of the Douglas-fir tussock moth and the western spruce budworm are recommended based on many years experience in sampling these species in eastern Oregon and Washington. It is shown that statistically reliable estimates of larval density can be made for a population by sampling host trees in a series of permanent plots in a...

  10. Compositional and structural constraints on the geologic history of eastern Tharsis Rise, Mars

    NASA Astrophysics Data System (ADS)

    Viviano-Beck, C. E.; Murchie, S. L.; Beck, A. W.; Dohm, J. M.

    2017-03-01

    Identification and mapping of distinct compositional units using high-resolution orbital imagery of the walls of Valles Marineris, Mars, provide key structural and environmental constraints on the geologic history of the eastern Tharsis Rise. Our results corroborate an overall vertical structure of the upper crust consistent with that inferred from previous studies. An upper unit spectrally consistent with basalt that has variable thickness is overlain on an early to possibly pre-Noachian substrate. The pre-/early-Noachian material is heterogeneous, dominated by low-calcium pyroxene-rich material but ranging locally from feldspathic to and olivine-rich. Aqueous alteration of pre-/early-Noachian rock to dominantly Fe/Mg-smectite is widespread and observed along the chasma walls from -4 to 1 km. However phyllosilicates outcrop discontinuously, suggesting that they were emplaced via impact excavation of even older altered material, or formed by non-uniform alteration driven by impact- or magma-related hydrothermal activity. A distinct, higher-temperature alteration assemblage identified by the presence of chlorite, zeolite, and associated carbonate (+/-serpentine) occurs on both the north and south walls of eastern Coprates Chasma in a confined longitudinal band, where the eastern margin of the Thaumasia Plateau intersects Valles Marineris. These secondary minerals are concentrated within a heavily fractured band exposed at a regional tectonic boundary along the margin of the Thaumasia Plateau, and likely record a regional zone of elevated crustal heat flow and fluid circulation. The generally north-south trending band exhibiting this distinct assemblage serves as a tracer for tectonic deformation; its continuity across Valles Marineris is incongruous with previously suggested lateral slip along the margin of a 'megaslide', and constrains left-lateral transtensional faulting to less than ∼25-50 km. Mapping of compositionally distinct outcrops to the west also

  11. Structural and petrologic evolution of the Lihue basin and eastern Kauai, Hawaii

    USGS Publications Warehouse

    Reiners, P.W.; Nelson, B.K.; Izuka, S.K.

    1999-01-01

    The topography of the eastern part of the Hawaiian island of Kauai is dominated by the Lihue basin, a large (???110 km2) semicircular depression bounded by steep cliffs and partly filled by late rejuvenated-stage (or post-erosional stage) volcanic material. As with other large, semicircular basins on ocean-island volcanoes, the subsurface geology and origin (e.g., structural collapse vs. fluvial erosion) of the Lihue basin are poorly understood. New analyses of samples collected from eastern Kauai and drill holes within the basin document several important features of the late-stage geologic evolution of Kauai. First, thick (>300 m) sequences of rejuvenated-stage Koloa Volcanics in the Lihue basin show systematic, basin-wide geochemical trends of increasingly incompatible elements with time, indicating a gradual decrease in the extent of partial melting of mantle sources with time. Second, beneath the rejuvenated-stage volcanics in the basin, a thin layer of postshield alkalic stage lavas (e.g., hawaiites and mugearites) overlies older shield-stage tholeiitic lavas of the Napali Member, indicating that the Lihue basin formed by structural collapse, not fluvial erosion. Third, a large (???2-5 km3) matrix-supported breccia, interpreted as deposits of one or more debris flows, is within the rejuvenated-stage volcanics throughout the basin, and correlates with surficial exposures of the Palikea Breccia west of the basin. Isotopic compositions of the bulk breccia are similar to those of tholeiites from the east side of Kauai, and distinct from those of west Kauai tholeiites. Clasts within the breccia are dominantly hawaiite and alkali gabbro. The source region of the breccia in the steep cliffs and highlands of the central massif to the west of the basin must contain magmatic products of an extensive postshield alkalic stage, including hawaiite flows and one or more large intrusive bodies or ponded sequences of alkali gabbro.

  12. Stable Isotopes Provide Insight into Population Structure and Segregation in Eastern North Atlantic Sperm Whales

    PubMed Central

    Borrell, Asunción; Velásquez Vacca, Adriana; Pinela, Ana M.; Kinze, Carl; Lockyer, Christina H.; Vighi, Morgana; Aguilar, Alex

    2013-01-01

    In pelagic species inhabiting large oceans, genetic differentiation tends to be mild and populations devoid of structure. However, large cetaceans have provided many examples of structuring. Here we investigate whether the sperm whale, a pelagic species with large population sizes and reputedly highly mobile, shows indication of structuring in the eastern North Atlantic, an ocean basin in which a single population is believed to occur. To do so, we examined stable isotope values in sequential growth layer groups of teeth from individuals sampled in Denmark and NW Spain. In each layer we measured oxygen- isotope ratios (δ18O) in the inorganic component (hydroxyapatite), and nitrogen and carbon isotope ratios (δ15N: δ13C) in the organic component (primarily collagenous). We found significant differences between Denmark and NW Spain in δ15N and δ18O values in the layer deposited at age 3, considered to be the one best representing the baseline of the breeding ground, in δ15N, δ13C and δ18O values in the period up to age 20, and in the ontogenetic variation of δ15N and δ18O values. These differences evidence that diet composition, use of habitat and/or migratory destinations are dissimilar between whales from the two regions and suggest that the North Atlantic population of sperm whales is more structured than traditionally accepted. PMID:24324782

  13. Stable isotopes provide insight into population structure and segregation in eastern North Atlantic sperm whales.

    PubMed

    Borrell, Asunción; Velásquez Vacca, Adriana; Pinela, Ana M; Kinze, Carl; Lockyer, Christina H; Vighi, Morgana; Aguilar, Alex

    2013-01-01

    In pelagic species inhabiting large oceans, genetic differentiation tends to be mild and populations devoid of structure. However, large cetaceans have provided many examples of structuring. Here we investigate whether the sperm whale, a pelagic species with large population sizes and reputedly highly mobile, shows indication of structuring in the eastern North Atlantic, an ocean basin in which a single population is believed to occur. To do so, we examined stable isotope values in sequential growth layer groups of teeth from individuals sampled in Denmark and NW Spain. In each layer we measured oxygen- isotope ratios (δ(18)O) in the inorganic component (hydroxyapatite), and nitrogen and carbon isotope ratios (δ(15)N: δ(13)C) in the organic component (primarily collagenous). We found significant differences between Denmark and NW Spain in δ(15)N and δ(18)O values in the layer deposited at age 3, considered to be the one best representing the baseline of the breeding ground, in δ(15)N, δ(13)C and δ(18)O values in the period up to age 20, and in the ontogenetic variation of δ(15)N and δ(18)O values. These differences evidence that diet composition, use of habitat and/or migratory destinations are dissimilar between whales from the two regions and suggest that the North Atlantic population of sperm whales is more structured than traditionally accepted.

  14. The effect of rearing environment on blue structural coloration of eastern bluebirds (Sialia sialis).

    PubMed

    Siefferman, Lynn; Hill, Geoffrey E

    2007-01-01

    We used a brood-size manipulation to test the effect of rearing environment on structural coloration of feathers grown by eastern bluebird (Sialia sialis) nestlings. Ultraviolet (UV)-blue structural coloration has been shown to be sexually selected in this species. Our experimental design took advantage of the growth of UV-blue wing feathers in nestlings that are retained as part of the first nuptial plumage. We cross-fostered nestlings to create enlarged and reduced broods with the purpose of manipulating parental feeding rates and measured the effect on nestling growth and plumage coloration. Brood size influenced feeding rates to offspring, but the effect varied with season. In general, male nestlings reared in reduced broods were fed more often, weighed more, and displayed brighter structural plumage compared to nestlings reared in enlarged broods. Female nestlings appeared to experience less adverse affects of brood enlargement, and we did not detect an effect of brood-size manipulation on the plumage coloration of female nestlings. Measures of plumage coloration in both males and females, however, were correlated to hatching date and nestling mass during feather development. These data provide empirical evidence that environmental quality can influence the development of the blue structural coloration of feathers and that males may be more sensitive to environmental fluctuations than females.

  15. The effect of rearing environment on blue structural coloration of eastern bluebirds (Sialia sialis)

    PubMed Central

    Hill, Geoffrey E.

    2009-01-01

    We used a brood-size manipulation to test the effect of rearing environment on structural coloration of feathers grown by eastern bluebird (Sialia sialis) nestlings. Ultraviolet (UV)-blue structural coloration has been shown to be sexually selected in this species. Our experimental design took advantage of the growth of UV-blue wing feathers in nestlings that are retained as part of the first nuptial plumage. We cross-fostered nestlings to create enlarged and reduced broods with the purpose of manipulating parental feeding rates and measured the effect on nestling growth and plumage coloration. Brood size influenced feeding rates to offspring, but the effect varied with season. In general, male nestlings reared in reduced broods were fed more often, weighed more, and displayed brighter structural plumage compared to nestlings reared in enlarged broods. Female nestlings appeared to experience less adverse affects of brood enlargement, and we did not detect an effect of brood-size manipulation on the plumage coloration of female nestlings. Measures of plumage coloration in both males and females, however, were correlated to hatching date and nestling mass during feather development. These data provide empirical evidence that environmental quality can influence the development of the blue structural coloration of feathers and that males may be more sensitive to environmental fluctuations than females. PMID:19655039

  16. Crustal structure of the Central-Eastern Greenland: results from the TopoGreenland refraction profile

    NASA Astrophysics Data System (ADS)

    Shulgin, Alexey; Thybo, Hans

    2014-05-01

    Until present, seismic surveys have only been carried out offshore and near the coasts of Greenland, where the crustal structure is affected by oceanic break-up. We present the deep seismic structure of the crust of the interior of Greenland, based on the new and the only existing so far seismic refraction/wide-angle reflection profile. The seismic data was acquired by a team of six people during a two-month long experiment in summer of 2011 on the ice cap in the interior of central-eastern Greenland. The presence of an up to 3.4 km thick ice sheet, permanently covering most of the land mass, made acquisition of geophysical data logistically complicated. The profile extends 310 km inland in E-W direction from the approximate edge of the stable ice cap near the Scoresby Sund across the center of the ice cap. 350 Reftek Texan receivers recorded high-quality seismic data from 8 equidistant shots along the profile. Explosive charge sizes were 1 ton at the ends and ca. 500 kg along the profile, loaded with about 125 kg at 35-85 m depth in individual boreholes. Given that the data acquisition was affected by the thick ice sheet, we questioned the quality of seismic records in such experiment setup. We have developed an automatic routine to check the amplitudes and spectra of the selected seismic phases and to check the differences/challenges in making seismic experiments on ice and the effects of ice on data interpretation. Using tomographic inversion and forward ray tracing modelling we have obtained the two-dimensional velocity model down to a 50 km depth. The model shows a decrease of crustal thickness from 47 km below the centre of Greenland in the western part of the profile to 40 km in its eastern part. Relatively high lower crustal velocities (Vp 6.8 - 7.3 km/s) in the western part of the TopoGreenland profile may result from past collision tectonics or, alternatively, may be related to the speculated passage of the Iceland mantle plume. Comparison of our results

  17. Geologic framework, structure, and hydrogeologic characteristics of the Knippa Gap area in eastern Uvalde and western Medina Counties, Texas

    USGS Publications Warehouse

    Clark, Allan K.; Pedraza, Diana E.; Morris, Robert R.

    2013-01-01

    By using data that were compiled and collected for this study and previous studies, a revised map was constructed depicting the geologic framework, structure, and hydrogeologic characteristics of the Knippa Gap area in eastern Uvalde and western Medina Counties, Tex. The map also shows the interpreted structural dip directions and interpreted location of a structural low (trough) in the area known as the Knippa Gap.

  18. Genetic diversity impacts of forest fires, forest harvesting, and alternative reforestation practices in black spruce (Picea mariana).

    PubMed

    Rajora, O P; Pluhar, S A

    2003-05-01

    Benchmarks were established for genetic diversity inherent in natural mature populations, and genetic diversity impacts of forest fires, clearcut harvesting and alternative natural and artificial silvicultural regeneration practices were determined in black spruce (Picea mariana). Allozymes of 32 loci were used to determine and compare genetic diversity and genetic relationships of adjacent or nearby four stand types: post-fire natural mature (FNM), post-fire natural young (FNR), post-harvest natural young (HNR) and post-harvest plantation (PLT), of black spruce at each of the four study sites located in two ecoregions in Manitoba: Ecoregion 90-Lac Seul Upland (Eastern) and Ecoregion 158 - Mid-Boreal Lowland (Northern). Both allelic- and genotypic-based genetic diversity parameters, as well as latent genetic potential, were determined. Black spruce populations showed typical moderate to high levels of allozyme genetic diversity. The mean genetic diversity parameters over the 16 black spruce populations sampled were as follows: percent loci polymorphic - 67%, mean number of alleles per locus - 2.52, effective number of alleles per locus - 1.70, observed heterozygosity - 0.222, expected heterozygosity - 0.308, mean number of observed genotypes per locus - 3.65, mean number of expected genotypes per locus - 5.03, genotype additivity (observed) - 116.8, genotype additivity (expected) - 161, genotype multiplicity (observed) - 6.16 x 10(15), genotype multiplicity (expected) - 2.06 x 10(19) and latent genetic potential - 26.12. The four stand types (FNM, FNR, HNR and PLT) had comparable and statistically similar genetic diversity levels at each of the four study sites as well as overall. No significant differences in black spruce genetic diversity levels were observed between the two ecoregions in Manitoba, as well as between the post-fire and post-harvest regenerated stands. No particular order of genetic relatedness among the four stand types was observed. Black spruce

  19. Comparison of tree size structure and growth for partially harvested and even-aged hemlock-spruce stands in southeast Alaska

    Treesearch

    Robert L. Deal; Troy Heithecker; Eric K. Zenner

    2010-01-01

    The effects of partial cutting on tree size structure and stand growth were evaluated in 52 plots in 13 stands in southeast Alaska that were partially harvested 53 to 96 years ago and compared with 50-year-old even-aged stands that developed after clearcutting. The net basal-area growth was greater in the partially cut plots than in the uncut plots, and basal-area...

  20. Lithospheric structure beneath Eastern Africa from joint inversion of receiver functions and Rayleigh wave velocities

    NASA Astrophysics Data System (ADS)

    Dugda, Mulugeta Tuji

    Crust and upper mantle structure beneath eastern Africa has been investigated using receiver functions and surface wave dispersion measurements to understand the impact of the hotspot tectonism found there on the lithospheric structure of the region. In the first part of this thesis, I applied H-kappa stacking of receiver functions, and a joint inversion of receiver functions and Rayleigh wave group velocities to determine the crustal parameters under Djibouti. The two methods give consistent results. The crust beneath the GEOSCOPE station ATD has a thickness of 23+/-1.5 km and a Poisson's ratio of 0.31+/-0.02. Previous studies give crustal thickness beneath Djibouti to be between 8 and 10 km. I found it necessary to reinterprete refraction profiles for Djibouti from a previous study. The crustal structure obtained for ATD is similar to adjacent crustal structure in many other parts of central and eastern Afar. The high Poisson's ratio and Vp throughout most of the crust indicate a mafic composition, suggesting that the crust in Afar consists predominantly of new igneous rock emplaced during the late synrift stage where extension is accommodated within magmatic segments by diking. In the second part of this thesis, the seismic velocity structure of the crust and upper mantle beneath Ethiopia and Djibouti has been investigated by jointly inverting receiver functions and Rayleigh wave group velocities to obtain new constraints on the thermal structure of the lithosphere. Crustal structure from the joint inversion for Ethiopia and Djibouti is similar to previously published models. Beneath the Main Ethiopian Rift (MER) and Afar, the lithospheric mantle has a maximum shear wave velocity of 4.1-4.2 km/s and extends to a depth of at most 50 km. In comparison to the lithosphere away from the East African Rift System in Tanzania, where the lid extends to depths of ˜100-125 km and has a maximum shear velocity of 4.6 km/s, the mantle lithosphere under the Ethiopian Plateau

  1. Nonlinear responses of white spruce growth to climate variability in interior Alaska

    Treesearch

    A.H. Lloyd; P.A. Duffy; D.H. Mann

    2013-01-01

    Ongoing warming at high latitudes is expected to lead to large changes in the structure and function of boreal forests. Our objective in this research is to determine the climatic controls over the growth of white spruce (Picea glauca (Moench) Voss) at the warmest driest margins of its range in interior Alaska. We then use those relationships to...

  2. Raman imaging of lignin and cellulose distribution in black spruce wood (Picea mariana) cell walls

    Treesearch

    Umesh P. Agarwal

    2005-01-01

    A detailed understanding of wood cell wall structure and organization is important from both fundamental and practical point of views. A state-of- the-art 633-nm laser based confocal Raman microscope was used in situ to investigate the cell wall organization of black spruce wood. Chemical information on lignin and cellulose from morphologically distinct cell wall...

  3. Determination of ethylenic residues in wood and TMP of spruce by FT-Raman spectroscopy

    Treesearch

    Umesh P. Agarwal; Sally A. Ralph

    2008-01-01

    A method based on FT-Raman spectroscopy is proposed for determining in situ concentrations of ethylenic residues in softwood lignin. Raman contributions at 1133 and 1654 cm-1, representing coniferaldehyde and coniferyl alcohol structures, respectively, were used in quantifying these units in spruce wood with subsequent conversion to concentrations in lignin. For...

  4. No evidence of an impact on the rhizosphere diazotroph community by the expression of Bacillus thuringiensis Cry1Ab toxin by Bt white spruce.

    PubMed

    Lamarche, Josyanne; Hamelin, Richard C

    2007-10-01

    Nitrogen fixation is one of the most important roles played by soil bacterial communities, as fixation supplies nitrogen to many ecosystems which are often N limited. As impacts on this functional group of bacteria might harm the ecosystem's health and reduce productivity, monitoring that particular group is important. Recently, a field trial with Bt white spruce, which constitutively expresses the Cry1Ab insecticidal toxin of Bacillus thuringiensis, was established. The Bt white spruce was shown to be resistant to spruce budworm. We investigated the possible impact of these genetically modified trees on soil nitrogen-fixing bacterial communities. The trial consisted of untransformed controls, GUS white spruce (transformed with the beta-glucuronidase gene), and Bt/GUS white spruce (which constitutively expresses both the Cry1Ab toxin and beta-glucuronidase) in a random design. Four years after planting, soil samples from the control and the two treatments from plantation as well as from two natural stands of white spruce were collected. Diazotroph diversity was assessed by extracting soil genomic DNA and amplifying a region of the nitrogenase reductase (nifH) gene, followed by cloning and sequencing. Analysis revealed that nitrogen-fixing communities did not differ significantly among the untransformed control, GUS white spruce, and Bt/GUS white spruce. Nevertheless, differences in diazotroph diversity were observed between white spruce trees from the plantation site and those from two natural stands, one of which grew only a few meters away from the plantation. We therefore conclude, in the absence of evidence that the presence of the B. thuringiensis cry1Ab gene had an effect on diazotroph communities, that either site and/or field preparation prior to planting seems to be more important in determining diazotroph community structure than the presence of Bt white spruce.

  5. Negative feedbacks on bark beetle outbreaks: widespread and severe spruce beetle infestation restricts subsequent infestation.

    PubMed

    Hart, Sarah J; Veblen, Thomas T; Mietkiewicz, Nathan; Kulakowski, Dominik

    2015-01-01

    Understanding disturbance interactions and their ecological consequences remains a major challenge for research on the response of forests to a changing climate. When, where, and how one disturbance may alter the severity, extent, or occurrence probability of a subsequent disturbance is encapsulated by the concept of linked disturbances. Here, we evaluated 1) how climate and forest habitat variables, including disturbance history, interact to drive 2000s spruce beetle (Dendroctonus rufipennis) infestation of Engelmann spruce (Picea engelmannii) across the Southern Rocky Mountains; and 2) how previous spruce beetle infestation affects subsequent infestation across the Flat Tops Wilderness in northwestern Colorado, which experienced a severe landscape-scale spruce beetle infestation in the 1940s. We hypothesized that drought and warm temperatures would promote infestation, whereas small diameter and non-host trees, which may reflect past disturbance by spruce beetles, would inhibit infestation. Across the Southern Rocky Mountains, we found that climate and forest structure interacted to drive the 2000s infestation. Within the Flat Tops study area we found that stands infested in the 1940s were composed of higher proportions of small diameter and non-host trees ca. 60 years later. In this area, the 2000s infestation was constrained by a paucity of large diameter host trees (> 23 cm at diameter breast height), not climate. This suggests that there has not been sufficient time for trees to grow large enough to become susceptible to infestation. Concordantly, we found no overlap between areas affected by the 1940s infestation and the current infestation. These results show a severe spruce beetle infestation, which results in the depletion of susceptible hosts, can create a landscape template reducing the potential for future infestations.

  6. Canopy gap dynamics of second-growth red spruce-northern hardwood stands in West Virginia

    USGS Publications Warehouse

    Rentch, J.S.; Schuler, T.M.; Nowacki, G.J.; Beane, N.R.; Ford, W.M.

    2010-01-01

    Forest restoration requires an understanding of the natural disturbance regime of the target community and estimates of the historic range of variability of ecosystem components (composition, structure, and disturbance processes). Management prescriptions that support specific restoration activities should be consistent with these parameters. In this study, we describe gap-phase dynamics of even-aged, second-growth red spruce-northern hardwood stands in West Virginia that have been significantly degraded following early Twentieth Century harvesting and wildfire. In the current stage of stand development, gaps tended to be small, with mean canopy gap and extended canopy gap sizes of 53.4m2 and 199.3m2, respectively, and a canopy turnover rate of 1.4%year-1. The majority of gaps resulted from the death of one or two trees. American beech snags were the most frequent gap maker, partially due to the elevated presence of beech-bark disease in the study area. Gaps ranged in age from 1 to 28 years, had a mean of 13 years, and were unimodal in distribution. We projected red spruce to be the eventual gap filler in approximately 40% of the gaps. However, we estimated that most average-sized gaps will close within 15-20 years before red spruce canopy ascension is projected (30-60 years). Accordingly, many understory red spruce will require more than one overhead release - an observation verified by the tree-ring record and consistent with red spruce life history characteristics. Based on our observations, silvicultural prescriptions that include overhead release treatments such as thinning from above or small gap creation through selection harvesting could be an appropriate activity to foster red spruce restoration in the central Appalachians. ?? 2010 Elsevier B.V.

  7. Negative Feedbacks on Bark Beetle Outbreaks: Widespread and Severe Spruce Beetle Infestation Restricts Subsequent Infestation

    PubMed Central

    Hart, Sarah J.; Veblen, Thomas T.; Mietkiewicz, Nathan; Kulakowski, Dominik

    2015-01-01

    Understanding disturbance interactions and their ecological consequences remains a major challenge for research on the response of forests to a changing climate. When, where, and how one disturbance may alter the severity, extent, or occurrence probability of a subsequent disturbance is encapsulated by the concept of linked disturbances. Here, we evaluated 1) how climate and forest habitat variables, including disturbance history, interact to drive 2000s spruce beetle (Dendroctonus rufipennis) infestation of Engelmann spruce (Picea engelmannii) across the Southern Rocky Mountains; and 2) how previous spruce beetle infestation affects subsequent infestation across the Flat Tops Wilderness in northwestern Colorado, which experienced a severe landscape-scale spruce beetle infestation in the 1940s. We hypothesized that drought and warm temperatures would promote infestation, whereas small diameter and non-host trees, which may reflect past disturbance by spruce beetles, would inhibit infestation. Across the Southern Rocky Mountains, we found that climate and forest structure interacted to drive the 2000s infestation. Within the Flat Tops study area we found that stands infested in the 1940s were composed of higher proportions of small diameter and non-host trees ca. 60 years later. In this area, the 2000s infestation was constrained by a paucity of large diameter host trees (> 23 cm at diameter breast height), not climate. This suggests that there has not been sufficient time for trees to grow large enough to become susceptible to infestation. Concordantly, we found no overlap between areas affected by the 1940s infestation and the current infestation. These results show a severe spruce beetle infestation, which results in the depletion of susceptible hosts, can create a landscape template reducing the potential for future infestations. PMID:26000906

  8. Serogenetic analysis in the study of the population structure of the eastern Adriatic (Croatia).

    PubMed

    Janićijević, B; Bakran, M; Papiha, S S; Chaventre, A; Roberts, D F

    1994-12-01

    The anthropogenetic structure of six island and peninsular populations (Brac, Hvar, Korcula, Peljesac, Silba, and Olib) of the eastern Adriatic, Croatia, is analyzed on the basis of the study of four different erythrocyte antigen systems or groups (ABO, Rhesus, Kell-Celano, P) and two erythrocyte isoenzyme systems (ACP, ESD). The average sample size was 555 individuals. Allele frequencies, genetic distances, and gene diversity values were computed. The results indicate that all the populations in question have preserved their separate characteristics over the course of their (micro)evolution to the present day; this is especially noticeable for the island populations of Korcula and Olib, as these are distinguished from the other four populations by a greater degree of isolation. Today's genetic structure of the six populations can be explained through the existing historical and cultural data for the region in question, which indicate that over the course of their ethnohistory they were all influenced by significant waves of immigration and selective emigrations that must have greatly shaped their present-day population structure.

  9. Structural pattern and emplacement mechanism of the Neka Valley nappe complex, eastern Alborz, Iran

    NASA Astrophysics Data System (ADS)

    Nabavi, Seyed Tohid; Rahimi-Chakdel, Aziz; Khademi, Mohsen

    2016-12-01

    The Neka Valley nappe complex is exposed in the south of Gorgan County in the eastern Alborz fold-and-thrust belt. We use the results of a regional survey of the structural data and their patterns to interpret the mechanisms that emplaced the unmetamorphosed nappes in the foreland fold-and-thrust belt of the Alborz Mountains. Most of the strain magnitudes are low in the study area but increase slightly towards what are probably their proximal ends. Strain ellipsoid is dominantly oblate with XY aligned along and across the belt (or the nappe complex). The average kinematic vorticity number, W k = 0.6 which indicates most of the strain partitioning resulted in a general shear. Most of Flinn's k values and α (the stretch along the shear plane) values are lower than 1. Structural indicators such as orthogonal extensional joints, pinch-and-swell structures, anastomosing cleavages, and listric normal and growth faults developed by push from the rear. Large-scale thrust complexes with opposed-dips such as triangle zones (as well as k and α-values <1) are compatible with the shear flow diverging distally and streamlines expected of the rear compression emplacement mechanism. Together with a later minor brittle deformation, these major ductile strains appears to provide a general model suitable for the emplacement of the nappes studied in a thin-skinned fold-and-thrust belt where the sedimentary cover strata shortened and imbricated in the upper crust.

  10. The rheological structure of the lithosphere in the Eastern Marmara region, Turkey

    NASA Astrophysics Data System (ADS)

    Oruç, Bülent; Sönmez, Tuba

    2017-05-01

    The aim of this work is to propose the geometries of the crustal-lithospheric mantle boundary (Moho) and lithosphere-asthenosphere boundary (LAB) and the 1D thermal structure of the lithosphere, in order to establish a rheological model of the Eastern Marmara region. The average depths of Moho and LAB are respectively 35 km and 51 km from radially averaged amplitude spectra of EGM08 Bouguer anomalies. The geometries of Moho and LAB interfaces are estimated from the Parker-Oldenburg gravity inversion algorithm. Our results show the Moho depth varies from 31 km at the northern part of North Anatolian Fault Zone (NAFZ) to 39 km below the mountain belt in the southern part of the NAFZ. The depth to the LAB beneath the same parts of the region ranges from 45 km to 55 km. Having lithospheric strength and thermal boundary layer structure, we analyzed the conditions of development of lithosphere thinning. A two-dimensional strength profile has been estimated for rheology model of the study area. Thus we suggest that the rheological structure consists of a strong upper crust, a weak lower crust, and a partly molten upper lithospheric mantle.

  11. The structure of the Africa-Anatolia plate boundary in the eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Vidal, Neus; Alvarez-Marrón, Joaquina; Klaeschen, Dirk

    2000-08-01

    New marine deep seismic reflection data from south of Cyprus to the Syrian coast provide images of the upper crustal structure of the Cyprean Arc indicating that the deformation is partitioned along strike-slip fault systems distributed over a wide zone, rather than forming a sharp plate boundary between African and Anatolian plates. Three major submarine strike-slip fault systems, tens of kilometers in length, are mapped, which follow bathymetric features and merge together toward the east. These structures exhibit the three-dimensional characteristics typical of strike-slip deformation zones throughout the seven pre-stack depth-migrated sections, including several sets of positive flower structures forming bathymetric ridges, and the intervening contemporaneous subbasins. Beneath the Plio-Quaternary sediments (500 m thick) that are blanketing the whole area and that reflect only the main surface traces of the fault systems, the subbasins are of varied dimensions and have rapid lateral changes in the thickness of the sedimentary fill. They include two major unconformities that have been correlated throughout the data marked by the M and K reflections. The M reflection is well imaged above varied thickness of Messinian evaporites, and the K reflection commonly appears at the base of syntectonic Tertiary age sediments. Within the eastern Cyprean Arc the K reflection corresponds to the basement-cover contact, indicating that the strike-slip tectonic scenario may have been active since the uppermost Cretaceous or lowermost Paleogene times to present. The active deformation front of the Alpine belt in the eastern Mediterranean corresponds to a strike-slip fault system that forms a 110° arc and coincides at the southern slope of the Hecateaus Rise, continuing along the Latakia Ridge to the Syrian coast. The mapped structures fit within a general kinematic framework of left-lateral transcurrent deformation that transfers slip from the subduction zone southwest of Cyprus

  12. Trophic size-structure of sailfish Istiophorus platypterus in eastern Taiwan estimated by stable isotope analysis.

    PubMed

    Tsai, C-N; Chiang, W-C; Sun, C-L; Shao, K-T; Chen, S-Y; Yeh, S-Z

    2014-02-01

    To examine trophic dynamics over different size classes, an isotopic study of sailfish Istiophorus platypterus life-history stages was carried out. Samples were collected from eastern Taiwan and the South China Sea during April 2009 and February 2012. A total of 263 samples (111-245 cm, lower jaw fork length, LLJFL ) were examined for changes in trophic structure in relation to LLJFL by using stable isotope analysis of carbon (δ(13) C) and nitrogen (δ(15) N). The δ(15) N values for I. platypterus ranged from 7·51 to 14·19‰ (mean ± s.d. = 12·06 ± 1·16‰) and the δ(13) C values ranged from -22·04 to -15·48‰ (mean ± s.d. = -17·62 ± 1·10‰). The δ(15) N values were positively dependent on LLJFL (r(2)  = 0·377), whereas δ(13) C were negatively dependent on LLJFL (r(2)  = 0·063). There were significantly different seasonal changes in nitrogen and carbon isotopic concentration, but no significant differences in concentrations between eastern Taiwan and the South China Sea were reported. The trophic level (TL ) of each LLJFL class was correlated, starting from 2·84 TL for size class I (LLJFL  < 140 cm) and reaching 5·03 TL for size class VI (LLJFL > 221 cm). The mean ± s.d. TL was 4·43 ± 0·19 for all samples. The results reveal that I. platypterus occupies a wide range of trophic levels and different size classes occupy different trophic positions in the pelagic ecosystem. © 2014 The Fisheries Society of the British Isles.

  13. Forest dynamics after successive spruce budworm outbreaks in mixedwood forests.

    PubMed

    Bouchard, Mathieu; Kneeshaw, Daniel; Bergeron, Yves

    2006-09-01

    In order to assess the long-term spatiotemporal influence of the spruce budworm in sub-boreal mixedwood forests, we studied the effect of three successive outbreaks in a region of western Quebec, Canada. We used dendrochronology to detect past outbreaks in three areas (111-185 ha), based on the recruitment age of balsam fir (Abies balsamea) and on growth patterns of white spruce (Picea glauca), the two main host species of this defoliating insect. We also used a series of aerial photographs taken between 1935 and 2003 to evaluate overstory mortality and post-outbreak succession patterns in these same areas. Individual outbreaks had a spatially homogenous impact on host species throughout the region, but successive outbreaks differed in intensity: the two outbreaks around 1910 and 1980 caused widespread mortality in the overstory, but an outbreak around 1945 had little impact, probably because the forest mosaic had not yet recuperated from the 1910 outbreak. No clear outbreak was detected in the later part of the 19th century. In portions of the study areas where the 1910 outbreak had a major impact, between 36% and 50% of the stands were reoccupied by balsam fir stands in the period up to the 1980 outbreak (cyclic succession), the rest being at least partly replaced by nonhost species such as Betula spp. Changes in forest composition after the 1910 outbreak were mostly associated with upper-slope positions in all study areas. The 1980 outbreak also had a higher impact than earlier outbreaks in lower-slope positions dominated by black spruce (Picea mariana)-balsam fir mixtures. These results suggest that, at the regional scale, the abundance of mature or over-mature balsam fir stands does not determine the outbreak cycle. When an outbreak occurs, however, its impact will be strongly constrained by forest characteristics such as stand composition and structure, which are themselves influenced by previous disturbances and slope position.

  14. The uppermost mantle shear wave velocity structure of eastern Africa from Rayleigh wave tomography: constraints on rift evolution

    NASA Astrophysics Data System (ADS)

    O'Donnell, J. P.; Adams, A.; Nyblade, A. A.; Mulibo, G. D.; Tugume, F.

    2013-08-01

    An expanded model of the 3-D shear wave velocity structure of the uppermost mantle beneath eastern Africa has been developed using earthquakes recorded by the AfricaArray East African Seismic Experiment in conjunction with data from permanent stations and previously deployed temporary stations. The combined data set comprises 331 earthquakes recorded on a total of 95 seismic stations spanning Kenya, Uganda, Tanzania, Zambia and Malawi. In this study, data from 149 earthquakes were used to determine fundamental-mode Rayleigh wave phase velocities at periods ranging from 20 to 182 s using the two-plane wave method, and then combined with the similarly processed published measurements and inverted for a 3-D shear wave velocity model of the uppermost mantle. New features in the model include (1) a low-velocity region in western Zambia, (2) a high-velocity region in eastern Zambia, (3) a low-velocity region in eastern Tanzania and (4) low-velocity regions beneath the Lake Malawi rift. When considered in conjunction with mapped seismicity, these results support a secondary western rift branch striking southwestwards from Lake Tanganyika, likely exploiting the relatively weak lithosphere of the southern Kibaran Belt between the Bangweulu Block and the Congo Craton. We estimate a lithospheric thickness of ˜150-200 km for the substantial fast shear wave anomaly imaged in eastern Zambia, which may be a southward subsurface extension of the Bangweulu Block. The low-velocity region in eastern Tanzania suggests that the eastern rift branch trends southeastwards offshore eastern Tanzania coincident with the purported location of the northern margin of the proposed Ruvuma microplate. Pronounced velocity lows along the Lake Malawi rift are found beneath the northern and southern ends of the lake, but not beneath the central portion of the lake.

  15. Above-ground space sequestration determines competitive success in juvenile beech and spruce trees.

    PubMed

    Kozovits, Alessandra R; Matyssek, Rainer; Winkler, J Barbro; Göttlein, Axel; Blaschke, Helmut; Grams, Thorsten E E

    2005-07-01

    A 2-yr phytotron study was conducted to investigate the intra- and inter-specific competitive behaviour of juvenile beech (Fagus sylvatica) and spruce (Picea abies). Competitiveness was analysed by quantifying the resource budgets that occur along structures and within occupied space of relevance for competitive interaction. Ambient and elevated CO(2) and ozone (O(3)) regimes were applied throughout two growing seasons as stressors for provoking changes in resource budgets, growth and allocation to facilitate the competition analysis. The hypothesis tested was that the ability to sequester space at low structural cost will determine the competitive success. Spruce was a stronger competitor than beech, as displayed by its higher above-ground biomass increments in mixed culture compared with monoculture. A crucial factor in the competitive success of spruce was its ability to enlarge crown volume at low structural costs, supporting the hypothesis. Interspecific competition with spruce resulted in a size-independent readjustment of above-ground allocation in beech (reduced leaf : shoot biomass ratio). The efficient use of resources for above-ground space sequestration proved to be a parameter that quantitatively reflects competitiveness.

  16. Crust and upper mantle resistivity structure at middle section of Longmenshan, eastern Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Wang, Xuben; Zhang, Gang; Fang, Hui; Luo, Wei; Zhang, Wei; Zhong, Qing; Cai, Xuelin; Luo, Haozhong

    2014-04-01

    Longmenshan is located in the eastern edge of the Tibetan Plateau. It is one of the hotspots of geophysical and geological studies in the world for its special tectonic characters and dynamic mechanism, especially after the 2008 Wenchuan earthquake (Ms 8.0). From 2008 to 2010, a 570 km Long-period magnetotelluric (LMT) and broadband magnetotelluric (MT) sounding profile across the Longmenshan fault zone has been carried out to investigate the crust and upper mantle resistivity structure. The coupling relationship of Longmenshan with the Songpan-Ganzi block and with the Sichuan basin of Yangtze block has been studied respectively. The analysis of the deep resistivity structure is of importance for the study of the geodynamic characteristics of the Wenchuan earthquake. The inversion reveals a high-low-high resistivity layer in the Songpan-Ganzi block, a low-high resistivity layer in the Sichuan basin and a complex resistivity structure in the Longmenshan area, respectively. There is a low resistivity layer in the middle and lower crust at the depth about 20-45 km beneath the Songpan-Ganzi block, which has shown that there may be a continuous slip layer in the crust, while there is no such a layer in the crust beneath the Sichuan basin. The thrust imbrication of resistivity structure in the upper crust beneath the Longmenshan indicates that the Songpan-Ganzi block is over thrusting onto the Yangtze block. And the low resistivity layer in the lower crust stretching downward to the bottom of the lithosphere beneath Longmenshan indicates that the Songpan-Ganzi block subducts below the lithosphere of Yangtze block. The complex structure of high resistivity massif in the lithosphere beneath Longmenshan provides some important evidence for the study of the mechanism of the 2008 Wenchuan earthquake.

  17. Top or Bottom-Heavy? Observational Constraints on the Vertical Structure of the Eastern Pacific ITCZ

    NASA Astrophysics Data System (ADS)

    Takahashi, K.; Huaman, L.

    2015-12-01

    The Intertropical Convergence Zone (ITCZ) is a key component of the eastern Pacific ocean-atmosphere system and its variability on seasonal to inter-annual and longer time scales. This feature is generally misrepresented in climate models, which show an excessively strong branch south of the equator. On the other hand, there is debate on what is the structure of the ITCZ in nature, particularly whether the latent heating and vertical velocity profiles are top or bottom-heavy. This knowledge is probably key to validate and improve the models. Most methods for estimating the vertical structure of the rate of latent heating
rely on profiles from field campaigns in other regions, combined with convective/stratiform fractions from the TRMM satellite.
In this study we use the precipitation profiles from the TRMM Precipitation Radar (PR), with approximations to the moisture conservation equation and the first law of thermodynamic, to directly estimate the vertical profiles of latent heating and vertical air velocity, respectively, in the ITCZ for the period 1998-2010. Due to limitations in the PR sensitivity and the inability to quantify solid precipitation, our results are restricted to the layer between the altitudes of 2 and 2.75 km. Nevertheless, we show that our results provide a strong constraint on the profiles and help determine which of the other estimates are more realistic. Our preliminary results for the northern hemisphere ITCZ in austral winter/spring are closer to the top-heavy estimations using TRMM-based algorithms (CSH, SLH and PRH) than to the bottom-heavy atmospheric reanalysis (ERA Interim and NCEP-NCAR), providing indirect evidence for a top-heavy profile. However, using the meridional wind measurements during the EPIC field campaign we find evidence that shallow ascent does exist below 2 km, consistent with the previously reported shallow meridional circulation but not as strong as the Reanalysis products indicate. Thus, our results support the

  18. Insights into Symbiont Population Structure among Three Vestimentiferan Tubeworm Host Species at Eastern Pacific Spreading Centers.

    PubMed

    Perez, Maëva; Juniper, S Kim

    2016-09-01

    The symbiotic relationship between vestimentiferan tubeworms and their intracellular chemosynthetic bacteria is one of the more noteworthy examples of adaptation to deep-sea hydrothermal vent environments. The tubeworm symbionts have never been cultured in the laboratory. Nucleotide sequences from the small subunit rRNA gene suggest that the intracellular symbionts of the eastern Pacific vent tubeworms Oasisia alvinae, Riftia pachyptila, Tevnia jerichonana, and Ridgeia piscesae belong to the same phylotype of gammaproteobacteria, "Candidatus Endoriftia persephone." Comparisons of symbiont genomes between the East Pacific Rise tubeworms R. pachyptila and T. jerichonana confirmed that these two hosts share the same symbionts. Two Ridgeia symbiont genomes were assembled from trophosome metagenomes from worms collected from the Juan de Fuca Ridge (one and five individuals, respectively). We compared these assemblies to those of the sequenced Riftia and Tevnia symbionts. Pangenome composition, genome-wide comparisons of the nucleotide sequences, and pairwise comparisons of 2,313 orthologous genes indicated that "Ca Endoriftia persephone" symbionts are structured on large geographical scales but also on smaller scales and possibly through host specificity. Remarkably, the intracellular symbionts of four to six species of eastern Pacific vent tubeworms all belong to the same phylotype of gammaproteobacteria, "Candidatus Endoriftia persephone." Understanding the structure, dynamism, and interconnectivity of "Ca Endoriftia persephone" populations is important to advancing our knowledge of the ecology and evolution of their host worms, which are often keystone species in vent communities. In this paper, we present the first genomes for symbionts associated with the species R. piscesae, from the Juan de Fuca Ridge. We then combine these genomes with published symbiont genomes from the East Pacific Rise tubeworms R. pachyptila and T. jerichonana to develop a portrait of the

  19. Insights into Symbiont Population Structure among Three Vestimentiferan Tubeworm Host Species at Eastern Pacific Spreading Centers

    PubMed Central

    Juniper, S. Kim

    2016-01-01

    ABSTRACT The symbiotic relationship between vestimentiferan tubeworms and their intracellular chemosynthetic bacteria is one of the more noteworthy examples of adaptation to deep-sea hydrothermal vent environments. The tubeworm symbionts have never been cultured in the laboratory. Nucleotide sequences from the small subunit rRNA gene suggest that the intracellular symbionts of the eastern Pacific vent tubeworms Oasisia alvinae, Riftia pachyptila, Tevnia jerichonana, and Ridgeia piscesae belong to the same phylotype of gammaproteobacteria, “Candidatus Endoriftia persephone.” Comparisons of symbiont genomes between the East Pacific Rise tubeworms R. pachyptila and T. jerichonana confirmed that these two hosts share the same symbionts. Two Ridgeia symbiont genomes were assembled from trophosome metagenomes from worms collected from the Juan de Fuca Ridge (one and five individuals, respectively). We compared these assemblies to those of the sequenced Riftia and Tevnia symbionts. Pangenome composition, genome-wide comparisons of the nucleotide sequences, and pairwise comparisons of 2,313 orthologous genes indicated that “Ca. Endoriftia persephone” symbionts are structured on large geographical scales but also on smaller scales and possibly through host specificity. IMPORTANCE Remarkably, the intracellular symbionts of four to six species of eastern Pacific vent tubeworms all belong to the same phylotype of gammaproteobacteria, “Candidatus Endoriftia persephone.” Understanding the structure, dynamism, and interconnectivity of “Ca. Endoriftia persephone” populations is important to advancing our knowledge of the ecology and evolution of their host worms, which are often keystone species in vent communities. In this paper, we present the first genomes for symbionts associated with the species R. piscesae, from the Juan de Fuca Ridge. We then combine these genomes with published symbiont genomes from the East Pacific Rise tubeworms R. pachyptila and T

  20. Rooting sitka spruce from southeast Alaska.

    Treesearch

    Donald L. Copes

    1987-01-01

    Rooting and shoot growth characteristics of 10-, 15-, and 20-year-old Sitka spruce cuttings were studied. Twigs from three branch orders were tested with or without 5000 parts per million indole-3-butyric acid (IBA) hormone treatment. Rooting success averaged 64 percent. The effect of ortet age on rooting success was not significant. Cuttings from first-order branch...

  1. Field Comparison of Spruce Budworm Pheromone Lures

    Treesearch

    David G. Grimble; David G. Grimble

    1987-01-01

    Four types of spruce budworm pheromone lures were tested to compare field longevity and efficiency. Biolures with three different pheromone release rates and Silk-PVC lures all caught male budworm moths throughout the moth flight period in proportion to the different release rates. Fumigant strips in traps to kill trapped moths were necessary.

  2. Helicopter Propwash Dislodges Few Spruce Budworms

    Treesearch

    Daniel T. Jennings; Mark W. Houseweart; Mark W. Houseweart

    1986-01-01

    Propwash treatments from a low-flying Bell 47-G2 helicopter dislodged few spruce budworm larvae and pupae from host balsam-fir trees. After propwash treatments, both larval-pupal densities on branch samples and in drop-tray collections near the ground were not significantly different between treated and control plots. Significantly more larvae were found in the lower...

  3. Red spruce restoration modeling in LANDIS

    Treesearch

    Melissa. Thomas-Van Gundy

    2010-01-01

    Scenarios for the restoration of red spruce (Picea rubens)-dominated forests on the Monongahela National Forest were created in the landscape simulation model LANDIS. The resulting landscapes were compared to existing habitat suitability index models for the Virginia northern flying squirrel (VNFS) and Cheat Mountain salamander (CMS) as a measure of...

  4. Photosynthetic capacity of red spruce during winter

    Treesearch

    P.G. Schaberg; J.B. Shane; P.F. Cali; J.R. Donnelly; G.R. Strimbeck

    1998-01-01

    We measured the photosynthetic capacity (Pmax) of plantation-grown red spruce (Picea rubens Sarg.) during two winter seasons (1993-94 and 1994-95) and monitored field photosynthesis of these trees during one winter (1993-94). We also measured Pmax for mature montane trees from January through May 1995....

  5. Structural studies of TiO2/wood coatings prepared by hydrothermal deposition of rutile particles from TiCl4 aqueous solutions on spruce (Picea Abies) wood

    NASA Astrophysics Data System (ADS)

    Pori, Pavel; Vilčnik, Aljaž; Petrič, Marko; Sever Škapin, Andrijana; Mihelčič, Mohor; Šurca Vuk, Angela; Novak, Urban; Orel, Boris

    2016-05-01

    A low temperature approach was developed for the deposition of rutile TiO2 particles on a wood surface by hydrolysis of TiCl4 in aqueous solutions acidified with HCl, and crystallization at 75 and 90 °C (1 h). Prior to hydrothermal treatment, Picea Abies wood was first soaked in a 0.5 mmol/l aqueous solution containing anionic surfactant sodium dodecyl sulphate (SDS, Sigma Aldrich) for 2 h at 80 °C. The crystal structure of the hydrothermally made rutile particles was determined with XRD, while the morphology of the deposited TiO2 particles and their distribution in the wood were examined with SEM and EDX measurements. The penetration and amount of deposited rutile particles could be modified by changing the deposition conditions. Thicker layers were obtained from more concentrated aqueous TiCl4 solutions with and without added HCl, and with longer deposition times and higher temperatures of the hydrothermal treatment. The interaction of TiO2 particles with hemicellulose and lignin in wood was established from infrared attenuated total reflection (FT-IR ATR) and Raman spectra measurements, from which the spectra of wood were subtracted. Analysis of the subtraction spectra showed the presence of titania particles on the wood surface, revealing also the establishment of TiO2-wood coordinative bonds of titanium ions with hemicellulose and lignin. The red frequency shift of the OH stretching modes suggested interaction of the TiO2 particles with water molecules of wood. TiO2 deposited on wood treated with SDS became hydrophobic (water contact angles (WCA) of 150°), contrasting the properties of untreated wood with a deposited TiO2 particle coating, which remained hydrophilic.

  6. Predicting community structure in snakes on Eastern Nearctic islands using ecological neutral theory and phylogenetic methods

    PubMed Central

    Burbrink, Frank T.; McKelvy, Alexander D.; Pyron, R. Alexander; Myers, Edward A.

    2015-01-01

    Predicting species presence and richness on islands is important for understanding the origins of communities and how likely it is that species will disperse and resist extinction. The equilibrium theory of island biogeography (ETIB) and, as a simple model of sampling abundances, the unified neutral theory of biodiversity (UNTB), predict that in situations where mainland to island migration is high, species-abundance relationships explain the presence of taxa on islands. Thus, more abundant mainland species should have a higher probability of occurring on adjacent islands. In contrast to UNTB, if certain groups have traits that permit them to disperse to islands better than other taxa, then phylogeny may be more predictive of which taxa will occur on islands. Taking surveys of 54 island snake communities in the Eastern Nearctic along with mainland communities that have abundance data for each species, we use phylogenetic assembly methods and UNTB estimates to predict island communities. Species richness is predicted by island area, whereas turnover from the mainland to island communities is random with respect to phylogeny. Community structure appears to be ecologically neutral and abundance on the mainland is the best predictor of presence on islands. With regard to young and proximate islands, where allopatric or cladogenetic speciation is not a factor, we find that simple neutral models following UNTB and ETIB predict the structure of island communities. PMID:26609083

  7. Predicting community structure in snakes on Eastern Nearctic islands using ecological neutral theory and phylogenetic methods.

    PubMed

    Burbrink, Frank T; McKelvy, Alexander D; Pyron, R Alexander; Myers, Edward A

    2015-11-22

    Predicting species presence and richness on islands is important for understanding the origins of communities and how likely it is that species will disperse and resist extinction. The equilibrium theory of island biogeography (ETIB) and, as a simple model of sampling abundances, the unified neutral theory of biodiversity (UNTB), predict that in situations where mainland to island migration is high, species-abundance relationships explain the presence of taxa on islands. Thus, more abundant mainland species should have a higher probability of occurring on adjacent islands. In contrast to UNTB, if certain groups have traits that permit them to disperse to islands better than other taxa, then phylogeny may be more predictive of which taxa will occur on islands. Taking surveys of 54 island snake communities in the Eastern Nearctic along with mainland communities that have abundance data for each species, we use phylogenetic assembly methods and UNTB estimates to predict island communities. Species richness is predicted by island area, whereas turnover from the mainland to island communities is random with respect to phylogeny. Community structure appears to be ecologically neutral and abundance on the mainland is the best predictor of presence on islands. With regard to young and proximate islands, where allopatric or cladogenetic speciation is not a factor, we find that simple neutral models following UNTB and ETIB predict the structure of island communities. © 2015 The Author(s).

  8. Biological structure and dynamics of fish assemblages in tributaries of eastern Lake Ontario

    USGS Publications Warehouse

    McKenna, James E.; Munawar, M.

    2003-01-01

    Interest in effective management of Great Lakes natural resources and restoration of native populations has stimulated interest in the conditions and ecological role of tributaries in the Great Lakes ecosystem. Rivers of Lake Ontario's eastern basin provide an excellent opportunity to examine important tributaries and their relationship to Lake Ontario. This paper reports on the results of an investigation of fish assemblage structure in lower reaches of the Salmon and Oswego Rivers and at their interfaces with Lake Ontario. These two systems represent conditions near the end points on a continuum from highly disturbed to pristine. They are also of great interest to resource managers for their important fisheries and other economic values. The objective was to identify distinct fish assemblages within these systems and relate their characteristics to biotic and abiotic conditions in an attempt to determine factors responsible for structuring and maintaining those species assemblages. This information is intended to provide baseline information for monitoring the status of these rivers and coastal systems and to aid in the development of models of ecological health.

  9. Intra-annual variability of anatomical structure and δ13C values within tree rings of spruce and pine in alpine, temperate and boreal Europe

    PubMed Central

    Vaganov, Eugene A.; Skomarkova, Marina V.; Knohl, Alexander; Brand, Willi A.; Roscher, Christiane

    2009-01-01

    Tree-ring width, wood density, anatomical structure and 13C/12C ratios expressed as δ13C-values of whole wood of Picea abies were investigated for trees growing in closed canopy forest stands. Samples were collected from the alpine Renon site in North Italy, the lowland Hainich site in Central Germany and the boreal Flakaliden site in North Sweden. In addition, Pinus cembra was studied at the alpine site and Pinus sylvestris at the boreal site. The density profiles of tree rings were measured using the DENDRO-2003 densitometer, δ13C was measured using high-resolution laser-ablation-combustion-gas chromatography-infra-red mass spectrometry and anatomical characteristics of tree rings (tracheid diameter, cell-wall thickness, cell-wall area and cell-lumen area) were measured using an image analyzer. Based on long-term statistics, climatic variables, such as temperature, precipitation, solar radiation and vapor pressure deficit, explained <20% of the variation in tree-ring width and wood density over consecutive years, while 29–58% of the variation in tree-ring width were explained by autocorrelation between tree rings. An intensive study of tree rings between 1999 and 2003 revealed that tree ring width and δ13C-values of whole wood were significantly correlated with length of the growing season, net radiation and vapor pressure deficit. The δ13C-values were not correlated with precipitation or temperature. A highly significant correlation was also found between δ13C of the early wood of one year and the late wood of the previous year, indicating a carry-over effect of the growing conditions of the previous season on current wood production. This latter effect may explain the high autocorrelation of long-term tree-ring statistics. The pattern, however, was complex, showing stepwise decreases as well as stepwise increases in the δ13C between late wood and early wood. The results are interpreted in the context of the biochemistry of wood formation and its linkage

  10. Intra-annual variability of anatomical structure and delta(13)C values within tree rings of spruce and pine in alpine, temperate and boreal Europe.

    PubMed

    Vaganov, Eugene A; Schulze, Ernst-Detlef; Skomarkova, Marina V; Knohl, Alexander; Brand, Willi A; Roscher, Christiane

    2009-10-01

    Tree-ring width, wood density, anatomical structure and (13)C/(12)C ratios expressed as delta(13)C-values of whole wood of Picea abies were investigated for trees growing in closed canopy forest stands. Samples were collected from the alpine Renon site in North Italy, the lowland Hainich site in Central Germany and the boreal Flakaliden site in North Sweden. In addition, Pinus cembra was studied at the alpine site and Pinus sylvestris at the boreal site. The density profiles of tree rings were measured using the DENDRO-2003 densitometer, delta(13)C was measured using high-resolution laser-ablation-combustion-gas chromatography-infra-red mass spectrometry and anatomical characteristics of tree rings (tracheid diameter, cell-wall thickness, cell-wall area and cell-lumen area) were measured using an image analyzer. Based on long-term statistics, climatic variables, such as temperature, precipitation, solar radiation and vapor pressure deficit, explained <20% of the variation in tree-ring width and wood density over consecutive years, while 29-58% of the variation in tree-ring width were explained by autocorrelation between tree rings. An intensive study of tree rings between 1999 and 2003 revealed that tree ring width and delta(13)C-values of whole wood were significantly correlated with length of the growing season, net radiation and vapor pressure deficit. The delta(13)C-values were not correlated with precipitation or temperature. A highly significant correlation was also found between delta(13)C of the early wood of one year and the late wood of the previous year, indicating a carry-over effect of the growing conditions of the previous season on current wood production. This latter effect may explain the high autocorrelation of long-term tree-ring statistics. The pattern, however, was complex, showing stepwise decreases as well as stepwise increases in the delta(13)C between late wood and early wood. The results are interpreted in the context of the biochemistry

  11. Significant role of structural fractures in Ren-Qiu buried-block oil field, eastern China

    SciTech Connect

    Fei, Q.; Xie-Pei, W.

    1983-03-01

    Ren-qui oil field is in a buried block of Sinian (upper Proterozoic) rocks located in the Ji-zhong depression of the western Bohai Bay basin in eastern China. The main reservoir consists of Sinian dolomite rocks. It is a fault block with a large growth fault on the west side which trends north-northeast with throws of up to 1 km (0.6 mi) or more. The source rocks for the oil are Paleogene age and overlie the Sinian dolomite rocks. The structural fractures are the main factor forming the reservoir of the buried-block oil field. Three structural lines, trending northeast, north-northeast, and northwest, form the regional netted fracture system. The north-northeast growth fault controlled the structural development of the buried block. The block was raised and eroded before the Tertiary sediments were deposited. In the Eocene Epoch, the Ji-zhong depression subsided, but the deposition, faulting, and related uplift of the block happened synchronously as the block was gradually submerged. At the same time, several horizontal and vertical karst zones were formed by the karst water along the netted structural fractures. The Eocene oil source rocks lapped onto the block and so the buried block, with many developed karst fractures, was surrounded by a great thickness of source rocks. As the growth fault developed, the height of the block was increased from 400 m (1300 ft) before the Oligocene to 1300 m (4250 ft) after. As the petroleum was generated, it migrated immediately into the karst fractures of the buried block along the growth fault. The karst-fractured block reservoir has an 800-m (2600-ft) high oil-bearing closure and good connections developed between the karst fractures.

  12. Seismic velocity structure and earthquake relocation for the magmatic system beneath Long Valley Caldera, eastern California

    NASA Astrophysics Data System (ADS)

    Lin, Guoqing

    2015-04-01

    A new three-dimensional (3-D) seismic velocity model and high-precision location catalog for earthquakes between 1984 and 2014 are presented for Long Valley Caldera and its adjacent fault zones in eastern California. The simul2000 tomography algorithm is applied to derive the 3-D Vp and Vp/Vs models using first-arrivals of 1004 composite earthquakes obtained from the original seismic data at the Northern California Earthquake Data Center. The resulting Vp model reflects geological structures and agrees with previous local tomographic studies. The simultaneously resolved Vp/Vs model is a major contribution of this study providing an important complement to the Vp model for the interpretation of structural heterogeneities and physical properties in the study area. The caldera is dominated by low Vp anomalies at shallow depths due to postcaldera fill. High Vp and low Vp/Vs values are resolved from the surface to ~ 3.4 km depth beneath the center of the caldera, corresponding to the structural uplift of the Resurgent Dome. An aseismic body with low Vp and high Vp/Vs anomalies at 4.2-6.2 km depth below the surface is consistent with the location of partial melt suggested by previous studies based on Vp models only and the inflation source locations based on geodetic modeling. The Sierran crystalline rocks outside the caldera are generally characterized with high Vp and low Vp/Vs values. The newly resolved velocity model improves absolute location accuracy for the seismicity in the study area and ultimately provides the basis for a high-precision earthquake catalog based on similar-event cluster analysis and waveform cross-correlation data. The fine-scale velocity structure and precise earthquake relocations are useful for investigating magma sources, seismicity and stress interaction and other seismological studies in Long Valley.

  13. Soft sediment deformation structures in the Lixian lacustrine sediments, eastern Tibetan Plateau and implications for postglacial seismic activity

    NASA Astrophysics Data System (ADS)

    Jiang, Hanchao; Zhong, Ning; Li, Yanhao; Xu, Hongyan; Yang, Huili; Peng, Xiaoping

    2016-10-01

    The eastern margin of the Tibetan Plateau is characterized by frequent earthquakes, which are closely associated with tectonic activity. To assess tectonic activity during the Late Pleistocene, we studied a well-exposed, 23-m-thick lacustrine sequence on the eastern margin of the plateau and found a variety of soft-sediment deformation (SSD) structures. Distributed in 24 stratigraphic levels, they comprise clastic dykes, ball-and-pillow structures, flame structures, clastic gravels, micro-faults, and slump folds. Most of the SSD structures indicate deformation mechanisms related to liquefaction and/or fluidization processes, most probably triggered by paleoseismic events. Given at least 4 historical earthquakes of M > 7 in the study area, most SSD structures in the Lixian lacustrine sequence indicate seismic events with M > 6 while simple flame structures point to some lower-magnitude earthquakes. OSL dating indicates that the sequence accumulated between 15.8 and 6.0 ka, giving a mean recurrence interval of 480 years for the 24 events, and demonstrating that lacustrine sediments in eastern Tibet have the potential to record a continuous seismic history on the centennial scale.

  14. Carbon sequestration by young Norway spruce monoculture

    NASA Astrophysics Data System (ADS)

    Pokorny, R.; Rajsnerova, P.; Kubásek, J.

    2012-04-01

    Many studies have been focused on allometry, wood-mass inventory, carbon (C) sequestration, and biomass expansion factors as the first step for the evaluation of C sinks of different plant ecosystems. To identify and quantify these terrestrial C sinks, and evaluate CO2 human-induced emissions on the other hand, information for C balance accounting (for impletion of commitment to Kyoto protocol) are currently highly needed. Temperate forest ecosystems have recently been identified as important C sink. Carbon sink might be associated with environmental changes (elevated [CO2], air temperature, N deposition etc.) and large areas of managed fast-growing young forests. Norway spruce (Pice abies L. Karst) is the dominant tree species (35%) in Central European forests. It covers 55 % of the total forested area in the Czech Republic, mostly at high altitudes. In this contribution we present C sequestration by young (30-35 year-old) Norway spruce monocultures in highland (650-700 m a.s.l., AT- mean annual temperature: 6.9 ° C; P- annual amount of precipitation: 700 mm; GL- growing season duration: 150 days) and mountain (850-900 m a.s.l.; AT of 5.5 ° C; P of 1300 mm; and GL of 120 days) areas and an effect of a different type of thinning. However, the similar stem diameter at the breast height and biomass proportions among above-ground tree organs were obtained in the both localities; the trees highly differ in their height, above-ground organ's biomass values and total above ground biomass, particularly in stem. On the total mean tree biomass needle, branch and stem biomass participated by 22 %, 24 % and 54 % in highland, and by 19 %, 23 % and 58 % in mountain area, respectively. Silvicultural management affects mainly structure, density, and tree species composition of the stand. Therefore, dendrometric parameters of a tree resulted from genotype, growth conditions and from management history as well. Low type of thinning (LT; common in highland) stimulates rather tree

  15. Spatial Variability of Atmospheric Boundary Layer Structure over the Eastern Equatorial Pacific.

    NASA Astrophysics Data System (ADS)

    Yin, Bingfan; Albrecht, Bruce A.

    2000-05-01

    Variations in the atmospheric boundary layer structure over the eastern equatorial Pacific are analyzed using 916 soundings collected during the First Global Atmospheric Research Program Global Experiment. Unstable boundary layer structures are observed much more frequently in soundings north of the ocean front located near 2.5°N in the eastern equatorial Pacific than in soundings south of the front. An objective criterion is applied to identify the presence of the transition layer, a weak stable layer near cloud base, in the soundings. The transition is observed in about 45% of the soundings in both the unstable and the inversion categories. A comparison of soundings over the cold tongue with those over the ITCZ indicates that differences in static stability between these regions are limited to the layer from the surface to about 850 mb, which is the mean height of the inversions capping the cloud layer over the cold tongue. The cold tongue soundings on average are found to be drier from the surface to 300 mb than the ITCZ soundings with the largest average difference (5 g kg1) between these two groups of soundings observed just above the inversion layer. Compensating subsidence from the ITCZ may account for some of the drying observed just above the cold tongue inversions, although horizontal advection may also be a factor. North-south cross sections (10°S-15°N) of potential temperature, mixing ratio, equivalent potential temperature, and meridional wind across the cold tongue-ITCZ complex (CTIC) were constructed for two longitudinal bands: 95°-105°W and 105°-115°W. There is little latitudinal variation of the average height of the trade inversion and the height of the transition layer across the CTIC. Although the average lifting condensation level (LCL) at 980 mb is located near the average top of the transition layers observed over the cold tongue, the average 980-mb LCL is close to the average height of the base of the transition layers observed over

  16. Third year effects of cloudwater and ozone on red spruce seedlings

    SciTech Connect

    Pier, P.A.; Thornton, F.C.; McDuffie, C. Jr. )

    1991-05-01

    The reduction in growth of high elevation red spruce in the eastern US has been attributed in part to greater exposure to atmospheric pollution which occurs at high elevation. The authors objective was to evaluate the impact of ambient ozone and cloudwater deposition on the growth of red spruce seedlings at a high elevation site. Potted native and Phyton-grown (Phyton Technologies) red spruce seedlings were exposed in open-top field chambers at Whitetop Mountain, Virginia (elevation 1,680) for the third season to treatments of: (1) exclusion of clouds and 50% reduction in ambient O{sub 3} (COE), (2) O{sub 3} with clouds excluded (CO), (3) exposure to clouds and O{sub 3}, as control chambers (CC), and (4) open plots (AA). Plant biomass components and diameter increment growth for both seedling types were not affected by treatments. Photosynthesis was not enhanced by removal of cloudwater and O{sub 3}. Respiration (R{sub d}) generally was not affected by treatments; however, R{sub d} in native seedling needles of previous year and two-year previous growth was significantly greater in CC than CO and COE on several sampling dates, indicating that cloudwater and O{sub 3} may be causing higher R{sub d}.

  17. Cloning and characterization of a Gasp homolog from the spruce budworm, Choristoneura fumiferana, and its putative role in cuticle formation.

    PubMed

    Nisole, A; Stewart, D; Bowman, S; Zhang, D; Krell, P J; Doucet, D; Cusson, M

    2010-10-01

    Proteins that are capable of binding chitin play essential roles in the synthesis and structural integrity of the insect cuticle and peritrophic matrix. In the course of developing expressed sequence tag (EST) libraries for the eastern spruce budworm, Choristoneura fumiferana, we identified an abundant cDNA encoding a homolog of the Drosophila "gasp" gene (Gene Analogous to Small Peritrophins). For the present work, we undertook the characterization of this new homolog, CfGasp, in an effort to identify its role during larval development. As shown for DmGasp, the C. fumiferana homolog was found to contain three type-2 chitin-binding domains (CBDs), which were also found in Gasp orthologs retrieved from GenBank. In a phylogenetic analysis, these Gasp proteins formed a tight cluster, distinct from the midgut-specific peritrophins with which they share the cysteine-containing CBDs so far considered absent from cuticular proteins. However, unlike what has been shown for peritrophins, CfGasp transcript levels were low in larval midguts and most abundant in epidermis, while they were low in trachea and ovaries. Transcript levels increased during larval molts in a pattern similar to that observed for exocuticular proteins in other insects. In addition, the recombinant protein was shown to be capable of binding chitin. Altogether, these results suggest a structural role for CfGasp in exocuticle formation.

  18. Structure and evolution of the Kerkennah high (eastern Tunisia) based on 3D seismic

    NASA Astrophysics Data System (ADS)

    Mastouri, R.; Marchant, R.; Jaboyedoff, M.; Bouaziz, S.; Marillier, F.

    2012-04-01

    The Kerkennah high is located in the near shore region of eastern Tunisia. It extends from the Jeffara-Djerba high in the south to the Medina-Lampadusa plateau in the north and encompasses the Kerkennah islands. A detailed knowledge of the tectonic processes affecting this area is essential in order to attempt to fully understand the controls of fracture development. In the Kerkennah islands, the marine and continental Plio-Quaternary series crop out affected by mojor faults trending NW-SE. In the subsurface, the stratigraphic section consists of an almost complete Mesozoic-Cenozoic sequence interbedded by major unconformities. The present-day Kerkennah high overlies an older basement lineament which may have been created during the Mesozoïc and Cenozoïc tectonic events. The 3D seismic reflection interpretation provides a good opportunity to analyze the subsurface images better than 2D seismic reflection. In fact, the geometrical characteristics of the different fault systems associated and the basin individualization are well established using 3D technique. In this paper we present, the NW-SE and NE-SW trending extensional faults, active during the Cenozoic and Quaternary in different phases. These faults form a series of grabens that vary in length from a few to several hundred kilometers. The structuring of NE-SW en echelon faults indicates a strike slip type of bordering faults. In this work, we focus on the evolution of the tectonic structures in the basin, in particular during the Eocene to Early Pliocene extension phase. The geodynamic evolution of Mesozoïc and Cenozoïc basins in the studied areas was dominated by several tectonic stages corresponding to a specific structural development in extension as well as in compression. This evolution will be discussed in the frame of major tectonic event that originated the opening of the Tethyan Ocean and the Mediterranean closing.

  19. Main eddy vertical structures observed in the four major Eastern Boundary Upwelling Systems

    NASA Astrophysics Data System (ADS)

    Pegliasco, Cori; Chaigneau, Alexis; Morrow, Rosemary

    2015-09-01

    In the four major Eastern Boundary Upwelling Systems (EBUS), mesoscale eddies are known to modulate the biological productivity and transport near-coastal seawater properties toward the offshore ocean, however little is known about their main characteristics and vertical structure. This study combines 10 years of satellite-altimetry data and Argo float profiles of temperature and salinity, and our main goals are (i) to describe the main surface characteristics of long-lived eddies formed in each EBUS and their evolution, and (ii) to depict the main vertical structure of the eddy-types that coexist in these regions. A clustering analysis of the Argo profiles surfacing within the long-lived eddies of each EBUS allows us to determine the proportion of surface and subsurface-intensified eddies in each region, and to describe their vertical structure in terms of temperature, salinity and dynamic height anomalies. In the Peru-Chile Upwelling System, 55% of the sampled anticyclonic eddies (AEs) have subsurface-intensified maximum temperature and salinity anomalies below the seasonal pycnocline, whereas 88% of the cyclonic eddies (CEs) are surface-intensified. In the California Upwelling System, only 30% of the AEs are subsurface-intensified and all of the CEs show maximum anomalies above the pycnocline. In the Canary Upwelling System, ˜40% of the AEs and ˜60% of the CEs are subsurface-intensified with maximum anomalies extending down to 800 m depth. Finally, the Benguela Upwelling System tends to generate ˜40-50% of weak surface-intensified eddies and ˜50-60% of much stronger subsurface-intensified eddies with a clear geographical distribution. The mechanisms involved in the observed eddy vertical shapes are discussed.

  20. Age, growth, and population structure of the smooth clam Callista chione in the eastern Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Ezgeta-Balić, Daria; Peharda, Melita; Richardson, Christopher A.; Kuzmanić, Marina; Vrgoč, Nedo; Isajlović, Igor

    2011-12-01

    The age, growth, and population structure of the smooth clam Callista chione were determined from samples collected by hydraulic dredge and SCUBA at four locations in the eastern Adriatic during 2007 and 2008. The age of 436 clam shells was determined from internal growth lines present in shell sections, and the timing of growth line formation was ascertained from monthly collections of clams to occur between August and September when sea water temperatures were maximal. In addition, age of 30 older individuals was verified with acetate peels of polished and etched shell sections. Differences were apparent in the age structure and growth rates of clams collected from the four locations studied. Von Bertalanffy growth (VBG) curves obtained for clams from these locations were L t = 72.4 (1-e-0.25(t - 2.68)) (Rab Island), L t = 74.5 (1-e-0.15(t + 0.57)) (Pag Bay), L t = 79.3 (1-e-0.34(t - 0.97)) (Cetina estuary), and L t = 82.5 (1-e-0.11(t + 2.88)) (Kaštela Bay). The age of the clams ranged between 3 and 44 years; median clam ages were similar at three of the four locations (14, 12, and 12 years, respectively), but was significantly lower in the Cetina estuary (4 years). The VBG growth constants recorded from clams were within the range of values obtained for this species by previous authors. The observed local differences in population structure indicate different levels of exploitation and illustrate the need to establish long-term strategies for a sustainable exploitation of smooth clams in the Croatian Adriatic.

  1. Structure of the Nemrut caldera (Eastern Anatolia, Turkey) and associated hydrothermal fluid circulation

    NASA Astrophysics Data System (ADS)

    Ulusoy, İnan; Labazuy, Philippe; Aydar, Erkan; Ersoy, Orkun; Çubukçu, Evren

    2008-07-01

    Plio-Quaternary volcanism played an important role in the present physical state of Eastern Anatolia. Mount Nemrut, situated to the west of Lake Van is one of the main volcanic centers in the region, with a spectacular summit caldera 8.5 × 7 km in diameter. The most recent eruptions of the volcano were in 1441, 1597 and 1692. Nemrut Lake covers the western half of the caldera; it is a deep, half-bowl-shaped lake with a maximum depth of 176 m. Numerous eruption centers are exposed within the caldera as a consequence of magma-water interaction. Current activity of Nemrut caldera is revealed as hot springs, fumaroles and a small, hot lake. Self-potential and bathymetric surveys carried out in the caldera were used to characterize the structure of the caldera and the associated hydrothermal fluid circulation. In addition, analyses based on digital elevation models and satellite imagery were used to improve our knowledge about the structure of the caldera. According to SP results, the flanks of the volcano represent "the hydrogeologic zone", whereas the intra-caldera region is an "active hydrothermal area" where the fluid circulation is controlled by structural discontinuities. There is also a northern fissure zone which exhibits hydrothermal signatures. Nemrut caldera collapsed piecemeal, with three main blocks. Stress controlling the collapse mechanism seems to be highly affected by the regional neotectonic regime. In addition to the historical activity, current hydrothermal and hydrogeologic conditions in the caldera, in which there is a large lake and shallow water table, increase the risk of the quiescent volcano.

  2. Habitat-independent spatial structure in populations of some forest birds in eastern North America.

    PubMed

    Ricklefs, Robert E

    2013-01-01

    The extent to which populations fill available ecological space is critical to evaluating niche-based theories of community assembly, but habitat suitability for populations is difficult to assess. The absence of a species from areas of otherwise suitable habitat might indicate localized species-specific influences, including biological interactions with competitors, consumers or pathogens, on local population persistence. I used Bray-Curtis ordination axis scores, based on the distributions of forest birds across census plots in eastern North America, as proxies of general features of habitat suitability to predict local abundances of each species of small land bird. I then applied spatial analysis to identify significant spatial structure (Moran's I) in residuals (positive or negative) from predicted local densities, which would indicate localized species-specific influences on population size. Fifty-eight of 79 species exhibited no significant spatial structure in residual abundances, indicating that the ordination axes reflect most of the spatial variation in environmental conditions and habitat characteristics that influence population distribution and density or that samples were too small to detect significant spatial variation. Twenty-one species exhibited significant habitat-independent spatial structure of residuals within distances of 100 km. Aggregations of residuals for these species were independently located, for the most part, and thus probably unrelated to general features of the environment that affect many species. Among factors considered as potential causes of spatial anomalies, positive density dependence (Allee effects), intraspecific social aggregation and area sensitivity in response to forest fragmentation find little support in this analysis. Because of the species-specific nature of these clustered residuals, specialized pathogens are potential candidates to drive spatial anomalies in host abundance.

  3. Contemporary Genetic Structure, Phylogeography and Past Demographic Processes of Wild Boar Sus scrofa Population in Central and Eastern Europe

    PubMed Central

    Kusza, Szilvia; Podgórski, Tomasz; Scandura, Massimo; Borowik, Tomasz; Jávor, András; Sidorovich, Vadim E.; Bunevich, Aleksei N.; Kolesnikov, Mikhail; Jędrzejewska, Bogumiła

    2014-01-01

    The wild boar (Sus scrofa) is one of the most widely distributed mammals in Europe. Its demography was affected by various events in the past and today populations are increasing throughout Europe. We examined genetic diversity, structure and population dynamics of wild boar in Central and Eastern Europe. MtDNA control region (664 bp) was sequenced in 254 wild boar from six countries (Poland, Hungary, Belarus, Ukraine, Moldova and the European part of Russia). We detected 16 haplotypes, all known from previous studies in Europe; 14 of them belonged to European 1 (E1) clade, including 13 haplotypes from E1-C and one from E1-A lineages. Two haplotypes belonged respectively to the East Asian and the Near Eastern clade. Both haplotypes were found in Russia and most probably originated from the documented translocations of wild boar. The studied populations showed moderate haplotype (0.714±0.023) and low nucleotide diversity (0.003±0.002). SAMOVA grouped the genetic structuring of Central and Eastern European wild boar into three subpopulations, comprising of: (1) north-eastern Belarus and the European part of Russia, (2) Poland, Ukraine, Moldova and most of Belarus, and (3) Hungary. The multimodal mismatch distribution, Fu's Fs index, Bayesian skyline plot and the high occurrence of shared haplotypes among populations did not suggest strong demographic fluctuations in wild boar numbers in the Holocene and pre-Holocene times. This study showed relatively weak genetic diversity and structure in Central and Eastern European wild boar populations and underlined gaps in our knowledge on the role of southern refugia and demographic processes shaping genetic diversity of wild boar in this part of Europe. PMID:24622149

  4. Contemporary genetic structure, phylogeography and past demographic processes of wild boar Sus scrofa population in Central and Eastern Europe.

    PubMed

    Kusza, Szilvia; Podgórski, Tomasz; Scandura, Massimo; Borowik, Tomasz; Jávor, András; Sidorovich, Vadim E; Bunevich, Aleksei N; Kolesnikov, Mikhail; Jędrzejewska, Bogumiła

    2014-01-01

    The wild boar (Sus scrofa) is one of the most widely distributed mammals in Europe. Its demography was affected by various events in the past and today populations are increasing throughout Europe. We examined genetic diversity, structure and population dynamics of wild boar in Central and Eastern Europe. MtDNA control region (664 bp) was sequenced in 254 wild boar from six countries (Poland, Hungary, Belarus, Ukraine, Moldova and the European part of Russia). We detected 16 haplotypes, all known from previous studies in Europe; 14 of them belonged to European 1 (E1) clade, including 13 haplotypes from E1-C and one from E1-A lineages. Two haplotypes belonged respectively to the East Asian and the Near Eastern clade. Both haplotypes were found in Russia and most probably originated from the documented translocations of wild boar. The studied populations showed moderate haplotype (0.714±0.023) and low nucleotide diversity (0.003±0.002). SAMOVA grouped the genetic structuring of Central and Eastern European wild boar into three subpopulations, comprising of: (1) north-eastern Belarus and the European part of Russia, (2) Poland, Ukraine, Moldova and most of Belarus, and (3) Hungary. The multimodal mismatch distribution, Fu's Fs index, Bayesian skyline plot and the high occurrence of shared haplotypes among populations did not suggest strong demographic fluctuations in wild boar numbers in the Holocene and pre-Holocene times. This study showed relatively weak genetic diversity and structure in Central and Eastern European wild boar populations and underlined gaps in our knowledge on the role of southern refugia and demographic processes shaping genetic diversity of wild boar in this part of Europe.

  5. ANOTHER LOOK AT THE EASTERN BANDED STRUCTURE: A STELLAR DEBRIS STREAM AND A POSSIBLE PROGENITOR

    SciTech Connect

    Grillmair, C. J.

    2011-09-01

    Using the Sloan Digital Sky Survey Data Release 7, we re-examine the Eastern Banded Structure (EBS), a stellar debris stream first discovered in Data Release 5 and more recently detected in velocity space by Schlaufman et al. The visible portion of the stream is 18{sup 0} long, lying roughly in the Galactic Anticenter direction and extending from Hydra to Cancer. At an estimated distance of 9.7 kpc, the stream is {approx}170 pc across on the sky. The curvature of the stream implies a fairly eccentric box orbit that passes close to both the Galactic center and to the Sun, making it dynamically distinct from the nearby Monoceros, Anticenter, and GD-1 streams. Within the stream is a relatively strong, 2{sup 0}-wide concentration of stars with a very similar color-magnitude distribution that we designate Hydra I. Given its prominence within the stream and its unusual morphology, we suggest that Hydra I is the last vestige of EBS's progenitor, possibly already unbound or in the final throes of tidal dissolution. Though both Hydra I and the EBS have a relatively high-velocity dispersion, given the comparatively narrow width of the stream and the high frequency of encounters with the bulge and massive constituents of the disk that such an eccentric orbit would entail, we suggest that the progenitor was likely a globular cluster and that both it and the stream have undergone significant heating over time.

  6. Conductivity structure of the lithosphere-asthenosphere boundary beneath the eastern North American margin

    NASA Astrophysics Data System (ADS)

    Attias, Eric; Evans, Rob. L.; Naif, Samer; Elsenbeck, Jimmy; Key, Kerry

    2017-02-01

    Tectonic plate motion and mantle dynamics processes are heavily influenced by the characteristics of the lithosphere-asthenosphere boundary (LAB), yet this boundary remains enigmatic regarding its properties and geometry. The processes involved in rifting at passive margins result in substantial alteration of the lithosphere through the transition from continental to oceanic lithologies. Here we employ marine magnetotelluric (MT) data acquired along a ˜135 km long profile, offshore Martha's Vineyard, New England, USA, to image the electrical conductivity structure beneath the New England continental margin for the first time. We invert the data using two different MT 2-D inversion algorithms and present a series of models that are obtained using three different parameterizations: fully unconstrained, unconstrained with an imposed LAB discontinuity and a priori constrained lithosphere resistivity. This suite of models infers variability in the depth of the LAB, with an average depth of 115 km at the eastern North America passive margin. Models robustly detect a ˜350 Ωm lithospheric anomalous conductivity zone (LACZ) that extends vertically through the entire lithosphere. Our preferred conductivity model is consistent with regional P-to-S receiver function data, shear-wave velocity, gravity anomalies, and prominent geological features. We propose that the LACZ is indicative of paleolithospheric thinning, either resulting from kimberlite intrusions associated with rifting and the New England Great Meteor hot spot track, or from shear-driven localized deformation related to rifting.

  7. Thrust structures in the eastern Dauphinois Zone (French Alps), north of the Pelvoux Massif

    NASA Astrophysics Data System (ADS)

    Beach, A.

    An examination of thrust structures in the eastern part of the Dauphinois Zone of the external French Alps (referred to in the literature as the Ultradauphinois Zone) shows that major basement thrusts climb up section to produce cover-basement synclines. These thrusts also climb laterally and are continuous with thrust in the cover rocks. The external basement massifs are recognized as thrust sheets with variably deformed and thrust cover sequences. The distinction made in the previous literature between the Dauphinois and Ultradauphinois Zones is no longer tenable. Cover thrusting proceeded by both smooth slip and rough slip, the latter producing a duplex of cover thrust slices. Restoration of this duplex indicates that a shortening of 70 km in the cover occured during its formation. Possible errors in this estimate include uncertainties in the original stratigraphic thickness and in the overall shape of the duplex. Another duplex is thought to have formed at a basement ramp created by the presence of an early basement normal fault. Partial footwall collapse of this basement ramp gave rise to a basement horse at the bottom of the duplex. The overall relation between cover and basement thrusting is indicated using a hanging wall sequence diagram. Recent geophysical studies suggest that the basement thrusts developed from a mid-crustal décollement which passes down dip to offset the Moho. Model studies of thin-skinned tectonics may not be appropriate to such thrust geometries.

  8. Thermocline Structure and ENSO Variability in the eastern equatorial Pacific during the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Clark, S.; Koutavas, A.; Lynch-Stieglitz, J.; Rustic, G.

    2015-12-01

    The mean state and variability of the eastern equatorial Pacific (EEP) during the Last Glacial Maximum (LGM) are of great interest because of the region's role in the El Niño-Southern Oscillation (ENSO) and global climate. We investigated changes in thermocline structure between the Late Holocene (LH) and LGM with stable isotopes of planktonic foraminifera in sediment cores from the Galápagos. We measured δ18O in two species—Globigerinoides ruber, inhabiting the surface mixed layer, and Neogloboquadrina dutertrei, inhabiting the deep thermocline—in order to evaluate the vertical temperature contrast between the two species. We also measured δ18O of individual N. dutertrei from modern (late 20th century) and LGM sediments in order to assess thermocline temperature variability related to ENSO activity. Our data indicate a reduced vertical contrast in the upper ocean during the LGM, which is most consistent with a deeper thermocline and thicker mixed layer. Additionally, δ18O of individual N. dutertrei shells shows 2.5 times greater population variance in the LGM than in the modern sample. This large variance indicates that thermocline temperatures were more variable during the LGM than today, consistent with more active ENSO. Together, these results imply that the mean state of the EEP was characterized by a deeper thermocline and greater ENSO variability. The results further show the potential for reconstructing ENSO variability from deep-sea sediments of the EEP, where other geological archives of ENSO are currently extremely limited.

  9. Shift of bacterial community structure along different coastal reclamation histories in Jiangsu, Eastern China.

    PubMed

    Hua, Jianfeng; Feng, Youzhi; Jiang, Qian; Bao, Xuewen; Yin, Yunlong

    2017-08-30

    Tideland reclamation has drastic effects on coastal ecosystem involved in soil microorganisms. However, the knowledge regarding temporal variations of microbial community along reclamation chronosequence and their environmental variable predictor is still poorly known. Using Illumina sequencing, we qualified bacterial community composition in soils collected from one tideland and four reclamation stages, i.e. 2-year, 7-year, 19-year and 39-year in Jiangsu, Eastern China. Across all samples, the dominant groups were Proteobacteria, Bacteroidete, Acidobacteria, Planctomycetes and Chloroflexi. Reclamation activity and its histories greatly altered bacterial community structure, and only 0.28% of phylotypes were shared by five soils. Specially, some typical marine bacteria (Gaetulibacter, Alcanivorax …) disappeared in reclamation soils, while other groups (Niabella, Flavisolibacter…) were gradually eminent. Generally, bacterial diversity and richness increased with reclamation histories. Bacterial community was correlated with most of soil physico-chemical properties. Amongst, mean weight diameter of soil aggregates (MWD) was detected as a primary factor predicting bacterial community composition. Together, our results indicated that effects of reclamation on bacterial community varied with diked histories, and MWD was a major factor predicting bacterial community during progressive reclamation. These findings offer predicting case study for understanding the impact of reclamation and its histories on microbial community in a coastal ecosystem.

  10. Adria-Europe crustal structure relationship in the Eastern Alps (project EASI)

    NASA Astrophysics Data System (ADS)

    Hetényi, György; Plomerová, Jaroslava; Bianchi, Irene; Kampfová Exnerová, Hana

    2016-04-01

    Project EASI is the first implemented Complementary Experiment within the AlpArray program (http://www.alparray.ethz.ch) and stands for Eastern Alpine Seismic Investigation. The seismological field experiment ran for one year, from Summer 2014 to Summer 2015, composed of 55 broadband stations deployed in zig-zag in a ca. 15 km-wide band along longitude 13.35°E, spanning 540 km from the Czech-German border to the Adriatic Sea. Here we present first results using P-to-S converted waves from teleseismic distances. The variation of Moho depth along the profile is analyzed and linked to the two colliding plates, Adria and Europe, as well as to the overlying lithospheric blocks of the Bohemian Massif. The suggested Moho "hole" between Adria and Europe is characterized. We investigate the anisotropic nature of the lower crust of both plates. We conclude on the structural relationship of Adria and Europe at the crustal level, and infer their respective positions at depth. Furthermore, preliminary S-to-P conversions illuminating the lithosphere-asthenosphere boundary test the significant depth variation of this boundary along the EASI transect and complement our receiver function study.

  11. Detectability of temporal changes in fine structures near the inner core boundary beneath the eastern hemisphere

    NASA Astrophysics Data System (ADS)

    Yu, Wen-che

    2016-04-01

    The inner core boundary (ICB), where melting and solidification of the core occur, plays a crucial role in the dynamics of the Earth's interior. To probe temporal changes near the ICB beneath the eastern hemisphere, I analyze differential times of PKiKP (dt(PKiKP)), double differential times of PKiKP-PKPdf, and PKiKP coda waves from repeating earthquakes in the Southwest Pacific subduction zones. Most PKiKP differential times are within ±30 ms, comparable to inherent travel time uncertainties due to inter-event separations, and suggest no systematic changes as a function of calendar time. Double differential times measured between PKiKP codas and PKiKP main phases show promising temporal changes, with absolute values of time shifts of >50 ms for some observations. However, there are discrepancies among results from different seismographs in the same calendar time window. Negligible changes in PKiKP times, combined with changes in PKiKP coda wave times on 5 year timescales, favor a smooth inner core boundary with fine-scale structures present in the upper inner core. Differential times of PKiKP can be interpreted in the context of either melting based on translational convection, or growth based on thermochemical mantle-inner core coupling. Small dt(PKiKP) values with inherent uncertainties do not have sufficient resolution to distinguish the resultant longitudinal (melting) and latitudinal (growth) dependencies predicted on the basis of the two models on 5 year timescales.

  12. Influences of forest structure, climate and species composition on tree mortality across the eastern US.

    PubMed

    Lines, Emily R; Coomes, David A; Purves, Drew W

    2010-10-13

    Few studies have quantified regional variation in tree mortality, or explored whether species compositional changes or within-species variation are responsible for regional patterns, despite the fact that mortality has direct effects on the dynamics of woody biomass, species composition, stand structure, wood production and forest response to climate change. Using bayesian analysis of over 430,000 tree records from a large eastern US forest database we characterised tree mortality as a function of climate, soils, species and size (stem diameter). We found (1) mortality is U-shaped vs. stem diameter for all 21 species examined; (2) mortality is hump-shaped vs. plot basal area for most species; (3) geographical variation in mortality is substantial, and correlated with several environmental factors; and (4) individual species vary substantially from the combined average in the nature and magnitude of their mortality responses to environmental variation. Regional variation in mortality is therefore the product of variation in species composition combined with highly varied mortality-environment correlations within species. The results imply that variation in mortality is a crucial part of variation in the forest carbon cycle, such that including this variation in models of the global carbon cycle could significantly narrow uncertainty in climate change predictions.

  13. Another Look at the Eastern Banded Structure: A Stellar Debris Stream and a Possible Progenitor

    NASA Astrophysics Data System (ADS)

    Grillmair, C. J.

    2011-09-01

    Using the Sloan Digital Sky Survey Data Release 7, we re-examine the Eastern Banded Structure (EBS), a stellar debris stream first discovered in Data Release 5 and more recently detected in velocity space by Schlaufman et al. The visible portion of the stream is 18° long, lying roughly in the Galactic Anticenter direction and extending from Hydra to Cancer. At an estimated distance of 9.7 kpc, the stream is ≈170 pc across on the sky. The curvature of the stream implies a fairly eccentric box orbit that passes close to both the Galactic center and to the Sun, making it dynamically distinct from the nearby Monoceros, Anticenter, and GD-1 streams. Within the stream is a relatively strong, 2°-wide concentration of stars with a very similar color-magnitude distribution that we designate Hydra I. Given its prominence within the stream and its unusual morphology, we suggest that Hydra I is the last vestige of EBS's progenitor, possibly already unbound or in the final throes of tidal dissolution. Though both Hydra I and the EBS have a relatively high-velocity dispersion, given the comparatively narrow width of the stream and the high frequency of encounters with the bulge and massive constituents of the disk that such an eccentric orbit would entail, we suggest that the progenitor was likely a globular cluster and that both it and the stream have undergone significant heating over time.

  14. Detectability of temporal changes in fine structures near the inner core boundary beneath the eastern hemisphere

    NASA Astrophysics Data System (ADS)

    Yu, W.

    2016-07-01

    The inner core boundary (ICB), where melting and solidification of the core occur, plays a crucial role in the dynamics of the Earth's interior. To probe temporal changes near the ICB beneath the eastern hemisphere, I analyze differential times of PKiKP (dt(PKiKP)), double differential times of PKiKP-PKPdf, and PKiKP coda waves from repeating earthquakes in the southwest Pacific subduction zones. dt(PKiKP) values are mostly within ±30 ms of one another, without systematic temporal dependence. Some observations of PKiKP coda waves have absolute time shifts of >50 ms relative to their main phases. The combination of temporal changes in PKiKP coda arrivals and negligible changes in PKiKP arrivals favors a smooth ICB with fine-scale structures in the upper inner core. dt(PKiKP) values are interpreted in the context of melting- or growth-induced ICB topography, based on dynamic models. Uncertainties in dt(PKiKP) prevent verification of ICB melting or growth on decadal time scales.

  15. Genetic variation and haplotype structures of innate immunity genes in eastern India

    PubMed Central

    Bairagya, Bijan B.; Bhattacharya, Paramita; Bhattacharya, Sujit K.; Dey, Biplab; Dey, Uposoma; Ghosh, Trina; Maiti, Sujit; Majumder, Partha P.; Mishra, Kankadeb; Mukherjee, Sinchita; Mukherjee, Souvik; Narayanasamy, K.; Poddar, Sonia; Roy, Neeta Sarkar; Sengupta, Priya; Sharma, Sangeeta; Sur, Dipika; Sutradhar, Debabrata; Wagener, Diane K.

    2009-01-01

    This study reports results of an extensive and comprehensive study of genetic diversity in 12 genes of the innate immune system in a population of eastern India. Genomic variation was assayed in 171 individuals by resequencing ~75 kb of DNA comprising these genes in each individual. Almost half of the 548 DNA variants discovered was novel. DNA sequence comparisons with human and chimpanzee reference sequences revealed evolutionary features indicative of natural selection operating among individuals, who are residents of an area with a high load of microbial and other pathogens. Significant differences in allele and haplotype frequencies of the study population were observed with the HapMap populations. Gene and haplotype diversities were observed to be high. The genetic positioning of the study population among the HapMap populations based on data of the innate immunity genes substantially differed from what has been observed for Indian populations based on data of other genes. The reported range of variation in SNP density in the human genome is one SNP per 1.19 kb (chromosome 22) to one SNP per 2.18 kb (chromosome 19). The SNP density in innate immunity genes observed in this study (>3 SNPs kb−1) exceeds the highest density observed for any autosomal chromosome in the human genome. The extensive genomic variation and the distinct haplotype structure of innate immunity genes observed among individuals have possibly resulted from the impact of natural selection. PMID:18396467

  16. Geological structure of the deep eastern Mediterranean Sea (east of 25 Degrees E)

    SciTech Connect

    Montadert, L.; Sage, L.; Letouzey, J. )

    1988-08-01

    The deformation fronts of the Cyprus arc and the Mediterranean ridge, extending from the Turkey-Syria boundary to north Cyrenacia, are the southernmost superficial expression of the convergence between the Eurasian and African plates. They separate the Eastern Mediterranean deep basin into two different structural units: (1) A thrust belt, northward, with the presence of Cenozoic sedimentary basins which could be considered piggy-back basins (Iskenderun, Adana, Cilicia, and Antalya basins). These basins, filled by 4,000 to 6,000 m of Cenozoic sediments, lie on a substratum composed of south-vergent nappes emplaced between the Late Cretaceous and the late Miocene. (2) A foreland area, southward, where the thick Herodotus and Levantine sedimentary basins, relatively undeformed, lie on the passive and subsident African continental margin initiated during Late Triassic or early Liassic time. Due to the still-active collision between the thrust belt and the Erathosthenes seamount, Cyprus was uplifted and today represents the emerged part of the deformation front. During the Messinian, with the isolation of the Mediterranean Sea, evaporitic deposits including a salt layer (sometimes more than 2,000 m thick) were widely distributed into the Iskenderun, Cilicia, Antalya, Levantine, and Herodotus basins. In these basins, the Messinian sedimentation was directly controlled by basin topography.

  17. Influences of Forest Structure, Climate and Species Composition on Tree Mortality across the Eastern US

    PubMed Central

    Lines, Emily R.; Coomes, David A.; Purves, Drew W.

    2010-01-01

    Few studies have quantified regional variation in tree mortality, or explored whether species compositional changes or within-species variation are responsible for regional patterns, despite the fact that mortality has direct effects on the dynamics of woody biomass, species composition, stand structure, wood production and forest response to climate change. Using Bayesian analysis of over 430,000 tree records from a large eastern US forest database we characterised tree mortality as a function of climate, soils, species and size (stem diameter). We found (1) mortality is U-shaped vs. stem diameter for all 21 species examined; (2) mortality is hump-shaped vs. plot basal area for most species; (3) geographical variation in mortality is substantial, and correlated with several environmental factors; and (4) individual species vary substantially from the combined average in the nature and magnitude of their mortality responses to environmental variation. Regional variation in mortality is therefore the product of variation in species composition combined with highly varied mortality-environment correlations within species. The results imply that variation in mortality is a crucial part of variation in the forest carbon cycle, such that including this variation in models of the global carbon cycle could significantly narrow uncertainty in climate change predictions. PMID:20967250

  18. Invasive symbiont bearing (and other) foraminifera altering the community structure of eastern Mediterranean rocky reefs environments

    NASA Astrophysics Data System (ADS)

    Hyams-Kaphzan, Orit; Perelis Grossowicz, Lydia; Almogi-Labin, Ahuva

    2015-04-01

    The rocky reefs of the Israeli eastern Mediterranean shelf constitute a highly diverse marine ecosystem rich in macroalgae and calcareous organisms. The benthic foraminiferal community living in this ecosystem is rapidly changing due to massive invasion of symbiont bearing foraminifera (SBF) as well as other foraminiferal species of tropical origin. This trend facilitated by the ongoing increase in temperature enables more tropical species to adjust to the eastern Mediterranean habitats. In order to document the status of the benthic foraminiferal community structure rocky reefs at Akhziv (AK) and Carmel Head (CH), northern Israel were sampled by scuba diving. Different macroalgae species, including invasive ones, accommodating the live epiphytic benthic foraminifera were sampled twice a year at AK and in each season at CH in three depth intervals between 5-20 m, during 2013-4. The numerical abundance of the group ranges between 170-3500 #/10cc (wet macroalgae volume) without any significant difference in standing stocks within regions, water depths or macroalgae preference. In total 77 benthic foraminiferal species were identified 71 in CH and only 43 at AK. Species richness per site varied between 3 and 42 with higher values at CH. 25% of all species were aliens, mostly Lessepsian, that comprise on average 70% - 84% of the numerical abundance of AK and CH respectively. Cluster analysis using benthic foraminifera relative abundance data did not correlate with the different macroalgae species, water depths or seasonality, indicating that the foraminiferal community in the two regions is quite homogenous. Amphistegina lobifera a Lessepsian migrant is by far the most common species on the Israeli rocky reefs occurring in all samples and comprising 18-93% of the foraminiferal community. Heterostegina depressa behaves similarly to A. lobifera though it occurs in lower numbers. Pararotalia calcariformata, a recently arriving SBF occupies mainly shallow water sites at CH

  19. Boreal peatland margins as repository sites of long-term natural disturbances of balsam fir/spruce forests

    NASA Astrophysics Data System (ADS)

    Lavoie, Martin; Filion, Louise; Robert, Élisabeth C.

    2009-05-01

    A multidisciplinary, high-resolution paleoecological study (Lepidoptera and plant remains, macroscopic charcoal, pollen) was conducted on a 4000-yr peat monolith extracted from the margin of an ombrotrophic peatland on Anticosti Island (Gulf of St. Lawrence, eastern Canada) to reconstruct the long-term natural disturbances (insect outbreaks, forest fires) of a balsam fir/spruce forest. We hypothesized that an activity of insect defoliators (spruce budworm, hemlock looper) was the main disturbance factor of conifer forests during the Late Holocene. The earliest remains of spruce budworm and hemlock looper were found ca. 3220 and 2350 cal yr BP, respectively. Peaks of insect head capsules occurred from ca. 1640 to ca. 625 cal yr BP. Low balsam fir pollen concentrations during this period suggest a lengthy episode (˜ 1000 yr) of high insect activity, resulting in extensive fir dieback and mortality. The long-term dynamics of the pristine balsam fir/spruce forests were mainly governed by the activity of insect defoliators. The limited extent and possibly the low occurrence of forest fires in the maritime environment of Anticosti Island allowed the development of mature coniferous stands propitious for insect infestations. Insect head capsules appeared to be a useful and effective tool for establishing insect presence and activity during the Holocene.

  20. Insect herbivory (Choristoneura fumiferana, Tortricidea) underlies tree population structure (Picea glauca, Pinaceae)

    PubMed Central

    Parent, Geneviève J.; Giguère, Isabelle; Germanos, Gaby; Lamara, Mebarek; Bauce, Éric; MacKay, John J.

    2017-01-01

    Variation in insect herbivory can lead to population structure in plant hosts as indicated by defence traits. In annual herbaceous, defence traits may vary between geographic areas but evidence of such patterns is lacking for long-lived species. This may result from the variety of selection pressures from herbivores, long distance gene flow, genome properties, and lack of research. We investigated the antagonistic interaction between white spruce (Picea glauca) and spruce budworm (SBW, Choristoneura fumiferana) the most devastating forest insect of eastern North America in common garden experiments. White spruces that are able to resist SBW attack were reported to accumulate the acetophenones piceol and pungenol constitutively in their foliage. We show that levels of these acetophenones and transcripts of the gene responsible for their release is highly heritable and that their accumulation is synchronized with the most devastating stage of SBW. Piceol and pungenol concentrations negatively correlate with rate of development in female SBW and follow a non-random geographic variation pattern that is partially explained by historical damage from SBW and temperature. Our results show that accumulation of acetophenones is an efficient resistance mechanism against SBW in white spruce and that insects can affect population structure of a long-lived plant. PMID:28205578

  1. Insect herbivory (Choristoneura fumiferana, Tortricidea) underlies tree population structure (Picea glauca, Pinaceae).

    PubMed

    Parent, Geneviève J; Giguère, Isabelle; Germanos, Gaby; Lamara, Mebarek; Bauce, Éric; MacKay, John J

    2017-02-16

    Variation in insect herbivory can lead to population structure in plant hosts as indicated by defence traits. In annual herbaceous, defence traits may vary between geographic areas but evidence of such patterns is lacking for long-lived species. This may result from the variety of selection pressures from herbivores, long distance gene flow, genome properties, and lack of research. We investigated the antagonistic interaction between white spruce (Picea glauca) and spruce budworm (SBW, Choristoneura fumiferana) the most devastating forest insect of eastern North America in common garden experiments. White spruces that are able to resist SBW attack were reported to accumulate the acetophenones piceol and pungenol constitutively in their foliage. We show that levels of these acetophenones and transcripts of the gene responsible for their release is highly heritable and that their accumulation is synchronized with the most devastating stage of SBW. Piceol and pungenol concentrations negatively correlate with rate of development in female SBW and follow a non-random geographic variation pattern that is partially explained by historical damage from SBW and temperature. Our results show that accumulation of acetophenones is an efficient resistance mechanism against SBW in white spruce and that insects can affect population structure of a long-lived plant.

  2. Relationships between prefire composition, fire impact, and postfire legacies in the boreal forest of Eastern Canada

    Treesearch

    Alain Leduc; Yves Bergeron; Sylvie Gauthier

    2007-01-01

    Canadian mixedwood forests have a high compositional and structural diversity. It includes both hardwood (aspen, balsam poplar, and white birch) and softwood (balsam fir, white spruce, black spruce, larch, and white cedar) species that can form pure stands or mixed stands. This heterogeneity results in a variety of vertical structural strata that can potentially...

  3. Convection and Easterly Wave Structure Observed in the Eastern Pacific Warm-Pool during EPIC-2001

    NASA Technical Reports Server (NTRS)

    Peterson, Walter A.; Cifelli, R.; Boccippio, D.; Rutledge, S. A.; Fairall, C. W.; Arnold, James E. (Technical Monitor)

    2002-01-01

    During September-October 2001, the East Pacific Investigation of Climate Processes in the Coupled Ocean-Atmosphere System (EPIC-2001) ITCZ field campaign focused on studies of deep convection in the warm-pool region of the East Pacific. In addition to the TAO mooring array, observational platforms deployed during the field phase included the NOAA ship RN Ronald H. Brown, the NSF ship RN Horizon, and the NOAA P-3 and NCAR C-130 aircraft. This study combines C-band Doppler radar, rawinsonde, and surface heat flux data collected aboard the RN Brown to describe ITCZ convective structure and rainfall statistics in the eastern Pacific as a function of 3-5 day easterly wave phase. Three distinct easterly wave passages occurred during EPIC-2001. Wind and thermodynamic data reveal that the wave trough axes exhibited positively correlated U and V winds and a slight westward phase tilt with height. A relatively strong (weak) northeasterly deep tropospheric shear followed the trough (ridge) axis. Temperature and humidity perturbations exhibited mid-to upper level cooling (warming) and drying (moistening) in the northerly (trough and southerly) phase. At low levels warming (cooling) occurred in the northerly (southerly) phase with little change in the relative humidity, though mixed layer mixing ratios were larger during the northerly phase. When composited, radar, sounding, lightning and surface heat flux observations suggest the following systematic behavior as a function of wave phase: approximately zero to one quarter wavelength ahead of (behind) the wave trough in northerly (southerly) flow, larger (smaller) CAPE, lower (higher) CIN, weaker (stronger) tropospheric shear, higher (lower) conditional mean rain rates, higher (lower) lightning flash densities, and more (less) robust convective vertical structure occurred. Latent and sensible heat fluxes reached a minimum in the northerly phase and then increased through the trough, reaching a peak during the ridge phase

  4. Structural and exhumational response to oroclinal bending at the Eastern Alps - Western Carpathian transition

    NASA Astrophysics Data System (ADS)

    Heberer, Bianca; Neubauer, Franz

    2017-04-01

    Curvature is an intriguing feature within many mountain belts worldwide. Several proposals have been made for deciphering the origin of curvature, however, there is still significant debate about the bend-forming mechanisms, the consequences as well as on how bending is accommodated within the lithosphere. Only few of the worldwide oroclines have been studied in detail and a variety of alternative controlling factors, such as the role of inherited structures, the rheological coupling between lower and upper plates, the presence of a basement promontory in the foreland and its particular geometry, and lateral orogen-parallel extrusion are likely underestimated or not considered at all. This study focuses on oroclinal bending at the transition from the W-E trending Eastern Alps to the SW-NE oriented Western Carpathians. There, the orogenic front is concave towards the Alpine foreland and the greatest degree of curvature (ca. 55°) is found adjacent to the Bohemian massif. The oroclinal axis runs from the Bohemian promontory to the South Burgenland high. Various competing mechanisms occurred, i.e. rotation around a stiff foreland promontory and lateral extrusion induced by tectonic escape due to the indentation of a microplate and extensional collapse due to slab-rollback beneath the Carpathians. Little is known for such cases, where bending around as well as overriding of a promontory occurs, particularly on how it controls the exhumational and structural architecture within the orogen itself. Based on a synthesis of low-T thermochronology and structural data we find a significant impact of oroclinal bending on exhumation and structures: Highest amounts of erosion occur in the immediate vicinity of the Bohemian promontory and along its prolongation in the South Burgenland high, corroborating that shortening and exhumation are most pronounced there and should decrease along-strike of the orogenic front. In the outer bend strong Miocene extensional thinning parallel to

  5. Three-dimensional structural evolution and kinematics of the Piedemonte Llanero, Central Llanos foothills, Eastern Cordillera, Colombia

    NASA Astrophysics Data System (ADS)

    Egbue, Obi; Kellogg, James

    2012-11-01

    The Piedemonte Llanero is a wedge duplex zone in the Llanos foothills on the eastern flank of the Eastern Cordillera of Colombia. It is located northeast of the Cusiana and Cupiagua hydrocarbon fields. The area is characterized by a series of moderate to high-angle duplexes with east-southeast verging thin-skinned and thick-skinned tectonics. We present a structural model constrained by 2-D and 3-D seismic reflection data, surface geology, and well data. The structural analysis is based on backward modeling (kinematic restoration) and forward modeling using transfer-flexural slip and fault slip fold algorithms. The structures are significantly tighter in the northern segment compared to the southern segment of the overthrust trend. We estimate approximately 17 km of shortening in the northern duplex zone, and about 26 km total shortening for the southern duplex zone. We propose that thin-skinned in-sequence imbricate thrust stack deformation produced most of the shortening. The main Andean deformation (80% of the total shortening) commenced in the Piedemonte area about 6 Ma with rapid shortening and uplift in the area resulting in the development of an active-roof duplex structure as the cover was bulldozed forward by a horse block (Monterralo anticline) ramping up to a detachment at the base of C2, then ramping to the surface as the Yopal thrust. Later the horse blocks in the wedge rose, underthrusting the cover in a passive-roof duplex triangle zone. This was followed by an out-of-sequence Laramide-style thick-skinned basement-uplift of the range which produced much of the structural relief of the Eastern Cordillera. Cenozoic deformation in the Eastern Cordillera has been primarily range-normal, but has involved an increasing component of mountain-parallel right-lateral shear in the last 2 Ma.

  6. EFFECTS OF EASTERN REDCEDAR ON SMALL MAMMAL COMMUNITY STRUCTURE IN THE OKLAHOMA CROSSTIMBERS

    EPA Science Inventory

    Increased abundance of eastern redcedar (Juniperus virginianus), a native but invasive species in the Great Plains, has been associated with reduced herbaceous biomass in the canopy zone, altered plant species composition, and reduced understory light and soil water content. By ...

  7. EFFECTS OF EASTERN REDCEDAR ON SMALL MAMMAL COMMUNITY STRUCTURE IN THE OKLAHOMA CROSSTIMBERS

    EPA Science Inventory

    Increased abundance of eastern redcedar (Juniperus virginianus), a native but invasive species in the Great Plains, has been associated with reduced herbaceous biomass in the canopy zone, altered plant species composition, and reduced understory light and soil water content. By ...

  8. Stem analysis of a long-lived black spruce clone at treeline

    SciTech Connect

    Payette, S.; Delwaide, A.; Morneau, C.; Lavoie, C. )

    1994-02-01

    Because of its ability to layer and to produce different phenotypes, black spruce (Picea mariana [Mill.] BSP.) develops a complex clonal structure ensuring its survival and longevity. Here we report tree stem development and demise of a black spruce clone at treeline over the last 500 yr. Since the 16th century, the apical meristems of the clonal spruce experienced three periods of stem development associated with brief warmings and two periods of stem decline corresponding to known cold spells of the Little Ice Age. Ortet development was particularly vigorous in the 16th century, while the two layered stems slowly developed in the late 17th century and in the 20th century, respectively. Stem decline appeared as a progressive process lasting for several decades in the form of a basipetal death-gradient along the bole amplified by the above/below snow-pack position. Stem elongation was possibly facilitated by lesser winter-snow abrasion and/or thicker snowpack. Clonal stem development may have important implications for spruce spread in the arctic tundra in a warmer world. 26 refs. 2 figs.

  9. Paleogene strata of the Eastern Los Angeles basin, California: Paleogeography and constraints on neogene structural evolution

    USGS Publications Warehouse

    McCulloh, T.H.; Beyer, L.A.; Enrico, R.J.

    2000-01-01

    Post-Paleogene dextral slip of 8-9 km is demonstrated for the southeastern part of the Whittier fault zone in the eastern Los Angeles basin area of southern California. A linear axis of greatest thickness for the combined upper Paleocene and lower to lower-middle Eocene clastic formations intersects the fault zone and is offset by it to give the new measure. Fragmentary evidence hints that the Whittier structural zone may have exerted control on bathymetric-topographic relief and sedimentation even in latest Paleocene (ca. 54 Ma). A clear topographic influence was exerted by 20-17 Ma. Strike-slip and present deformational style is younger than ca. 8 Ma. Our Paleogene isopach map extends as far west as long 117??58'W and is a foundation for companion zonal maps of predominant lithology and depositional environments. Integration of new palynological data with published biostratigraphic results and both new and published lithologic and sedimentological interpretations support the zonal maps. Reconstruction of marine-nonmarine facies and fragmented basin margins yields a model for the northeastern corner of a Paleogene coastal basin. Palinspastic adjustment for the Neogene-Quaternary Whittier fault offset and a reasoned westerly extension of the northern edge of the basin model yield a reconstruction of Paleogene paleogeography-paleoceanography. Our reconstruction is based partly on the absence of both Paleocene and Eocene deposits beneath the unconformable base of the middle Miocene Topanga Group in a region nowhere less than 15 km wide between the Raymond-Sierra Madre-Cucamonga fault zone and the northern edge of the Paleocene basin. Thus, Paleogene strata of the Santa Monica Mountains could not have been offset from the northern extension of the Santa Ana Mountains by sinistral slip on those boundary faults. Structural rearrangements needed to accommodate the clockwise rotation of the western Transverse Ranges from the early Miocene starting position are thereby

  10. Population genetic structure of two columnar cacti with a patchy distribution in eastern Brazil.

    PubMed

    Moraes, Evandro M; Abreu, Aluana G; Andrade, Sónia C S; Sene, Fabio M; Solferini, Vera N

    2005-11-01

    The genetic variability and population genetic structure of six populations of Praecereus euchlorus and Pilosocereus machrisii were investigated. The genetic variability in single populations of Pilosocereus vilaboensis, Pilosocereus aureispinus, and Facheiroa squamosa was also examined. All of these cacti species have a patchy geographic distribution in which they are restricted to small areas of xeric habitats in eastern Brazil. An analysis of genetic structure was used to gain insights into the historical mechanisms responsible for the patchy distribution of P. euchlorus and P. machrisii. High genetic variability was found at the populational level in all species (P=58.9-92.8%, A(p)=2.34-3.33, H(e)=0.266-0.401), and did not support our expectations of low variability based on the small population size. Substantial inbreeding was detected within populations (F(IS)=0.370-0.623). In agreement with their insular distribution patterns, P. euchlorus and P. machrisii had a high genetic differentiation (F(ST)=0.484 and F(ST)=0.281, respectively), with no evidence of isolation by distance. Accordingly, estimates of gene flow (N(m)) calculated from F(ST) and private alleles were below the level of N(m)=1 in P. machrisii and P. euchlorus. These results favored historical fragmentation as the mechanism responsible for the patchy distribution of these two species. The genetic distance between P. machrisii and P. vilaboensis was not compatible with their taxonomic distinction, indicating a possible local speciation event in this genus, or the occurrence of introgression events.

  11. The vertical structure of the eastern Pacific ITCZs and associated circulation using the TRMM Precipitation Radar and in situ data

    NASA Astrophysics Data System (ADS)

    Huaman, L.; Takahashi, K.

    2016-08-01

    The atmospheric circulation associated with the eastern Pacific single and double ITCZs, particularly its vertical structure, is little known due to the sparce observations. Using precipitation profiles from the Tropical Rainfall Measure Mission (TRMM) Precipitation Radar, with approximations to the liquid water and energy budget equations, we estimated vertical profiles of latent heating and vertical velocity in the far eastern Pacific (95°W-85°W) ITCZs in the 800-730 hPa layer. We combined this with Eastern Pacific Investigation of Climate campaign (EPIC2001) and other in situ data to produce a preliminary characterization of the meridional-vertical circulation. We found evidence of a double-cell structure in boreal fall between the ITCZ and the equator, with both shallow and upper level peaks in vertical velocity. In spring, the flow poleward of the two ITCZs has a single-cell structure, although around the equator it shows some hints of the double cells. Reanalysis and satellite-based data are shown to be unreliable for describing the vertical structure of the circulation.

  12. The P and S wave velocity structure of the mantle beneath eastern Africa and the African superplume anomaly

    NASA Astrophysics Data System (ADS)

    Mulibo, Gabriel D.; Nyblade, Andrew A.

    2013-08-01

    P and S relative arrival time residuals from teleseismic earthquakes recorded on over 60 temporary AfricaArray broadband seismic stations deployed in Uganda, Tanzania, and Zambia between 2007 and 2011 have been inverted, together with relative arrival time residuals from earthquakes recorded by previous deployments, for a tomographic image of mantle wave speed variations extending to a depth of 1200 km beneath eastern Africa. The image shows a low-wave speed anomaly (LWA) well developed at shallow depths (100-200 km) beneath the Eastern and Western branches of the Cenozoic East African rift system and northwestern Zambia, and a fast wave speed anomaly at depths ≤ 350 km beneath the central and northern parts of the East African Plateau and the eastern and central parts of Zambia. At depths ≥350 km the LWA is most prominent under the central and southern parts of the East African Plateau and dips to the southwest beneath northern Zambia, extending to a depth of at least 900 km. The amplitude of the LWA is consistent with a ˜150-300 K thermal perturbation, and its depth extent indicates that the African superplume, originally identified as a lower mantle anomaly, is likely a whole mantle structure. A superplume extending from the core-mantle boundary to the surface implies an origin for the Cenozoic extension, volcanism, and plateau uplift in eastern Africa rooted in the dynamics of the lower mantle.

  13. Space-time structure of the 2003 geomagnetic jerk at Mid-Eastern Asia

    NASA Astrophysics Data System (ADS)

    Ou, Jiaming; Du, Aimin; Xu, Wenyao; Yang, Dongmei

    2015-04-01

    The 2003 jerk has an abrupt change in the geomagnetic secular variation (SV), and was recognized as a local phenomenon of internal origin from the satellite observations (Olsen and Mandea, 2007). Notable strength of the 2003 jerk is located at Mid-Eastern Asia. The temporal and spatial features at this area are important to resolve the Earth's core fluid flow dynamics at local scale (e.g. Wardinski et al., 2008). We investigate the temporal-spatial development of the 2003 jerk in more detail at Mid-Eastern Asia with the ground-based observations and CHAOS-3 core field model. We select the data in the international geomagnetic quiet days to calculate the monthly means. In order to reduce the influence of the external field, we adopt a function comprising the terms associated with the indices of the geomagnetic activity, and the terms of the periodic signals on the observatory monthly means data (Stewart and Whaler, 1992). We then use an empirical AR-2 model to represent the internal field signals in the observatory data. The extreme detection is applied to identify the jerk in the SV time series. The onset time and the strength of the 2003 jerk are obtained through the detection for geomagnetic field component, X, Y and Z. The maximum of the strength of the 2003 jerk is located under the Indian mainland. The onset time of this jerk propagates approximately southeastward. Two jerks in 2001 and 2003 for the Z component are further compared and they are confirmed as independent processes. We suggest the jerk in 2001 identical to the well known 1999 jerk in Europe (Mandea et al., 2000). Our results reveal the fine structures of the 2003 jerk that corroborate the conclusions in previous studies. The larger scale time-spatial structure given by the AR-2 model constructed from ground observatory data (monthly values) is consistent with the results from the CHAOS-3 model. This structure can be applied for further inversion of the local core surface fluid flow motions

  14. Structural development of the Dieppe-Hampshire Basin (Eastern English Channel): Contribution of new seismic data

    NASA Astrophysics Data System (ADS)

    Jollivet-Castelot, Martin; Gaullier, Virginie; Paquet, Fabien; Chanier, Frank; Thinon, Isabelle; Lasseur, Eric; Averbuch, Olivier

    2017-04-01

    The Dieppe-Hampshire Basin is a Cenozoic basin crossing the eastern English Channel, between SE of England and the French coast. This basin and its borders developed during the Cenozoic, a period of overall tectonic inversion, in response to the opening of the North Atlantic Ocean and Pyrenean-alpine deformation episodes. Both extensional and subsequent compressional deformations within this area involve the reactivation of older major regional structures, inherited from the Variscan Orogeny. However, the detailed structural development of the Dieppe-Hampshire Basin still remains poorly constrained, as well as the detailed stratigraphic framework of Cenozoic series, notably in terms of seismic stratigraphy and sequence stratigraphy. New very high resolution seismic data, acquired during the oceanographic cruise "TREMOR" (R/V "Côtes de la Manche", 2014, 1800 kilometers of Sparker profiles), and bathymetric data from SHOM and UKHO, have allowed to image the sedimentary filling and tectonic structures of the Dieppe-Hampshire Basin and adjacent areas. The interpretation was first focused on a seismic facies analysis that led to evidence numerous unconformities and seismic units ranging from the Upper Cretaceous to the Bartonian (Late Eocene). The interpretation of the seismic profiles also allowed to map precisely many tectonic features, as faults, folds and monoclinal flexures. Thanks to the new data, we especially imaged the complexity of the deformation within the highest tectonized zones of the region, along the Nord-Baie de Seine Basin and offshore the Boulonnais coast with an unprecedented resolution. The expression of the deformation appears to be very different between the Mesozoic and the Cenozoic series, with prevailing folding affecting the Cenozoic strata whereas the Mesozoic series are predominantly faulted. This deformation pattern illustrates two major structural trends, respectively E-W and NW-SE directed, both syn- to post-Bartonian in age. The first

  15. On the formation of lignin polysaccharide networks in Norway spruce.

    PubMed

    Oinonen, Petri; Zhang, Liming; Lawoko, Martin; Henriksson, Gunnar

    2015-03-01

    In this study we were mirroring suggested in vivo phenomena of lignin-hemicellulose complex formation in vitro, by cross-linking Norway spruce (Picea abies) galactoglucomannans, xylans and lignin moieties to high molecular weight complexes by laccase treatment. We were able to observe the oxidation and cross-linking of non-condensed guaiacyl-type phenolic moieties attached to both of the hemicelluloses by (31)P NMR and size-exclusion chromatography. We suggest that hemicelluloses-lignin complexes form covalently linked structural units during the early stages of lignification via radical enzymatic cross-linking catalyzed by laccase. This work shows that the hemicellulose molecules in wood are covalently linked to two or more lignin units thereby making them suited for forming network structures.

  16. Growth trends in pruned red spruce trees

    Treesearch

    Barton M. Blum; Dale S. Solomon

    1980-01-01

    The diameter growth of red spruce with 1/6, 1/3, and 1/2 crown removed was compared with that of unpruned trees for 18 growing seasons. Although removal of 1/6 of the live crown did not adversely affect annual radial growth, compared with that of the controls, removal of 1/3 and 1/2 had a significant effect on the cumulative radial growth for 2 and 9 growing seasons,...

  17. Parallel and lineage-specific molecular adaptation to climate in boreal black spruce.

    PubMed

    Prunier, Julien; Gérardi, Sébastien; Laroche, Jérôme; Beaulieu, Jean; Bousquet, Jean

    2012-09-01

    In response to selective pressure, adaptation may follow different genetic pathways throughout the natural range of a species due to historical differentiation in standing genetic variation. Using 41 populations of black spruce (Picea mariana), the objectives of this study were to identify adaptive genetic polymorphisms related to temperature and precipitation variation across the transcontinental range of the species, and to evaluate the potential influence of historical events on their geographic distribution. Population structure was first inferred using 50 control nuclear markers. Then, 47 candidate gene SNPs identified in previous genome scans were tested for relationship with climatic factors using an F(ST) -based outlier method and regressions between allele frequencies and climatic variations. Two main intraspecific lineages related to glacial vicariance were detected at the transcontinental scale. Within-lineage analyses of allele frequencies allowed the identification of 23 candidate SNPs significantly related to precipitation and/or temperature variation, among which seven were common to both lineages, eight were specific to the eastern lineage and eight were specific to the western lineage. The implication of these candidate SNPs in adaptive processes was further supported by gene functional annotations. Multiple evidences indicated that the occurrence of lineage-specific adaptive SNPs was better explained by selection acting on historically differentiated gene pools rather than differential selection due to heterogeneity of interacting environmental factors and pleiotropic effects. Taken together, these findings suggest that standing genetic variation of potentially adaptive nature has been modified by historical events, hence affecting the outcome of recent selection and leading to different adaptive routes between intraspecific lineages. © 2012 Blackwell Publishing Ltd.

  18. Basement structural control on Cretaceous pull-apart basins of the central Eastern Egypt Desert

    NASA Astrophysics Data System (ADS)

    McCaffrey, K.; El Kazzaz, Y.; Holdsworth, B.

    2006-12-01

    The present-day Red Sea / Gulf of Suez rift system is attributed to extensional block faulting with along-axis segmentation into sub-basins with different dip polarities. The northwestern margin of the Red Sea - Gulf of Suez rift system is exposed for about 400 km along the northwestern Red Sea coast near Quseir to the tip of the Gulf of Suez at Suez City. This area contains elements of the pre-Red Sea structural pattern which has been viewed in similar terms as one of fault-related basin formation. Four distinct depocenters (sub-basins) separated by complex accommodation zones are present containing 500-700m thick section ranging in age from the Late Cretaceous to the Middle Eocene. Each sub-basin is asymmetric, bounded on one side by a major NW-trending border fault system with large throws (3-6 km in general) with a dominant strata dip direction toward the border fault system. These basins are arranged in en echelon patterns and now form separate elongated ridges surrounded by basement rocks. Our study of the tectonic evolution of the central eastern section of the Gulf of Suez rift and the Northwestern Red Sea has focused on the interaction of pre-existing basement fabrics with the pre-Red Sea structural development. The study involved analysis of LandsatTM images and aerial photographs integrated with results from reconnaissance geological mapping. Our provisional results indicate that the Gebel Um Hammad/Duwi and Hammadat sub-basins were sited in pull-apart structures created by dextral reactivation of E-W to ENE-WSW trending basement fault zones. We show how the basin-bounding fault systems, lower order normal faults and folds in both hangingwall sequences and in basement are compatible with a Late Cretaceous to Early Eocene strike-slip regime. In contrast, the main Red Sea Gulf of Suez rift shows no evidence for strike-slip influence with the main boundary faults cutting across basement fabrics, however, as pointed out by previous authors, rift segmentation

  19. Seismic velocity structure and seismotectonics of the eastern San Francisco Bay region, California

    USGS Publications Warehouse

    Hardebeck, J.L.; Michael, A.J.; Brocher, T.M.

    2007-01-01

    The Hayward Fault System is considered the most likely fault system in the San Francisco Bay Area, California, to produce a major earthquake in the next 30 years. To better understand this fault system, we use microseismicity to study its structure and kinematics. We present a new 3D seismic-velocity model for the eastern San Francisco Bay region, using microseismicity and controlled sources, which reveals a ???10% velocity contrast across the Hayward fault in the upper 10 km, with higher velocity in the Franciscan Complex to the west relative to the Great Valley Sequence to the east. This contrast is imaged more sharply in our localized model than in previous regional-scale models. Thick Cenozoic sedimentary basins, such as the Livermore basin, which may experience particularly strong shaking during an earthquake, are imaged in the model. The accurate earthquake locations and focal mechanisms obtained by using the 3D model allow us to study fault complexity and its implications for seismic hazard. The relocated hypocenters along the Hayward Fault in general are consistent with a near-vertical or steeply east-dipping fault zone. The southern Hayward fault merges smoothly with the Calaveras fault at depth, suggesting that large earthquakes may rupture across both faults. The use of the 3D velocity model reveals that most earthquakes along the Hayward fault have near-vertical strike-slip focal mechanisms, consistent with the large-scale orientation and sense of slip of the fault, with no evidence for zones of complex fracturing acting as barriers to earthquake rupture.

  20. Eastern Barents Sea: crustal structure of the craton-shelf transition.

    NASA Astrophysics Data System (ADS)

    Shulgin, Alexey; Mjelde, Rolf

    2015-04-01

    The former disputed area of the Barents Sea is a hot area for geophysical investigations, since little is known so far about its deep crustal structure, while the area is of a particular interest for hydrocarbon prospecting. Once the territorial disputes have been finally settled recently, a regional ocean bottom seismometer (OBS) survey was conducted in this area in summer 2012. The seismic line is a northeast-southwest trending profile located in the easternmost area of the Norwegian waters. The transect is approximately 600 km long and includes marine and onshore parts. The major part of the profile was recorded on the 38 OBS with an average spacing of 13 km. In addition, 80 land stations (with 1 km spacing) were deployed during the field campaign: 50 of them on the southern continuation of the marine profile, and 30 were deployed semi-parallel to the marine profile along the eastern coast of the Varanger Peninsula. We present the crustal model of the craton-shelf transition obtained from the seismic tomography and gravity modeling. The model shows the presence of six principally different crustal domains, which correlate with the near-surface observations. The interpretation of these changes along the profile links to the different tectonic settings along the profile. Presence of the large volumes of the underplated material is attributed to the rifting events on the shelf. The lateral variations in the seismic velocities in the onshore part of the transect is interpreted as a change from the typical cratonic crust to the continental type crust of the Varanger terrane. We also show the results of the ongoing work on the S-waves tomography modeling for the same profile. The combined interpretation of P and S data will provide additional details on the compositional differences between crustal domains and will give extra information on the origin of the underplating.

  1. Orogenic structure of the Eastern Alps, Europe, from TRANSALP deep seismic reflection profiling

    NASA Astrophysics Data System (ADS)

    Lüschen, Ewald; Lammerer, Bernd; Gebrande, Helmut; Millahn, Karl; Nicolich, Rinaldo; Transalp Working Group

    2004-09-01

    The TRANSALP Group, comprising of partner institutions from Italy, Austria and Germany, acquired data on a 340 km long deep seismic reflection line crossing the Eastern Alps between Munich and Venice. Although the field work was split into four campaigns, between fall 1998 and summer 2001, the project gathered for the first time a continuous profile across the Alps using consistent field acquisition and data processing parameters. These sections span the orogen itself, at its broadest width, as well as the editor Fred Davey and the two adjacent basins. Vibroseis and explosion data, complementary in their depth penetration and resolution characteristics, were obtained along with wide-angle and teleseismic data. The profile shows a bi-vergent asymmetric structure of the crust beneath the Alpine axis which reaches a maximum thickness of 55 km, and 80-100 km long transcrustal ramps, the southward dipping 'Sub-Tauern-Ramp' and the northward-dipping 'Sub-Dolomites-Ramp'. Strongly reflective patterns of these ramps can be traced towards the north to the Inn Valley and towards the south to the Valsugana thrust belt, both of which show enhanced seismicity in the brittle upper crust. The seismic sections do not reveal any direct evidence for the presence of the Periadriatic Fault system, the presumed equivalent to the Insubric Line in the Western Alps. According to our new evolutionary model, the Sub-Tauern-Ramp is linked at depth with remnants of the subducted Penninic Ocean. The 'crocodile'-type model describes an upper/lower crustal decoupling and wedging of both the European and the Adriatic-African continents.

  2. Analysis of Structural Styles in the High-dipping Tectonic Belts in the Eastern Sichuan area, China

    NASA Astrophysics Data System (ADS)

    He, D.; Wu, X.; Guo, Q.; Zhang, J.

    2016-12-01

    The Eastern Sichuan area, referred to here as the eastern part of the Sichuan Basin, is receiving increasing attention from the geologists and oil finders. At present, several structural models have been proposed for interpreting the complicated structures in the Eastern Sichuan area. One model considered the Eastern Sichuan structures as a result of progressive deformation along the basement detachments from wide-spaced to box-type to trough-like structures in the NE-SW trending compression. The other model based on regional structural evolution correlated them to fold styles that were built in earlier extension, middle inversion and later compression, and another model interpreted them as the double detachment-modification structures under such a structural context. The tectonic stress fields and main stress directions that these three models were established based on do not change, but the stress-propagation direction and structural styles are different significantly. The first model shows that the anticlines became narrow upward during the progressive detachment deformation along Middle-Upper Cambrian gypsum-mudstone layers, Lower Silurian mudstone layers and Lower Triassic gypsum-mudstone layers. The second model suggests that there were abundant thrust faults formed along the duplex thrusting front, constituting multiple flower-type faults with less development upward but more dipping folds. The third model is that the Middle-Upper Cambrian gypsum-mudstone layers, Lower Silurian mudstone layers and Lower Triassic gypsum-mudstone layers were controlled by SE-trending compression in the Indosinian period (T2-J1), forming sandwich structure and deforming along the three detachments. During the late Yanshanian to Himalayan periods (K2-N2), these structures developed further in SW-trending compression. The deep gypsum layer as detachment layer began to material transition in the buckling from wing to core part of the folds, triggering the formation of the wide

  3. Study of Reservoir Heterogencities and Structural Features Affecting Production in the Shallow Oil Zone, Eastern Elk Hills Area, California

    SciTech Connect

    Janice Gillespie

    2004-11-01

    Late Neogene (Plio-Pleistocene) shallow marine strata of the western Bakersfield Arch and Elk Hills produce hydrocarbons from several different reservoirs. This project focuses on the shallow marine deposits of the Gusher and Calitroleum reservoirs in the Lower Shallow Oil Zone (LSOZ). In the eastern part of the study area on the Bakersfield Arch at North and South Coles Levee field and in two wells in easternmost Elk Hills, the LSOZ reservoirs produce dry (predominantly methane) gas. In structurally higher locations in western Elk Hills, the LSOZ produces oil and associated gas. Gas analyses show that gas from the eastern LSOZ is bacterial and formed in place in the reservoirs, whereas gas associated with oil in the western part of the study area is thermogenic and migrated into the sands from deeper in the basin. Regional mapping shows that the gas-bearing LSOZ sands in the Coles Levee and easternmost Elk Hills area are sourced from the Sierra Nevada to the east whereas the oil-bearing sands in western Elk Hills appear to be sourced from the west. The eastern Elk Hills area occupied the basin depocenter, farthest from either source area. As a result, it collected mainly low-permeability offshore shale deposits. This sand-poor depocenter provides an effective barrier to the updip migration of gases from east to west. The role of small, listric normal faults as migration barriers is more ambiguous. Because our gas analyses show that the gas in the eastern LSOZ reservoirs is bacterial, it likely formed in-place near the reservoirs and did not have to migrate far. Therefore, the gas could have been generated after faulting and accumulated within the fault blocks as localized pools. However, bacterial gas is present in both the eastern AND western parts of Elk Hills in the Dry Gas Zone (DGZ) near the top of the stratigraphic section even though the measured fault displacement is greatest in this zone. Bacterial gas is not present in the west in the deeper LSOZ which

  4. Anatomical and physiological responses of Colorado blue spruce to vehicle exhausts.

    PubMed

    Qin, Xuebo; Sun, Nan; Ma, Lixin; Chang, Yingqiao; Mu, Liqiang

    2014-09-01

    In order to examine whether the leaves of the Colorado blue spruce (Picea pungens) are damaged or not by traffic pollution, the traits of the anatomy and physiology of its leaves are investigated by exposure to vehicle exhausts in a laboratory experiment lasting 30 days. The results show that both the anatomical structures and physiological traits of the leaves are significantly affected by vehicle exhausts. The anatomical structures, including epidermis, cuticle, palisade, and spongy parenchyma are modified when exposed to the high concentrations (≥ 0.4 mg/m(3)) of vehicle exhausts. However, physiological traits such as total chlorophyll content are not changed when exposed to different concentrations of vehicle exhaust. Unlike the total chlorophyll content, the electrical conductivities increased, whereas the POD activities decreased when presented in vehicle exhausts. The present study indicates that the Colorado blue spruce changes its anatomical structures and physiological traits to avoid possible damage by vehicle exhausts.

  5. Deep resistivity structure along the Longmen Mountain fault zone in the eastern Tibetan plateau of China

    NASA Astrophysics Data System (ADS)

    Wang, X.; Zhang, G.; Luo, W.; Luo, H.; Cai, X.; Zhou, Y.; Zhang, W.; Qin, Q.

    2012-12-01

    1.Introduction Many researchers (e.g.,Wang et al.,2009) have proposed the relevant knowledge of tectonic evolution and dynamic characteristics of the Longmen Mountain belt as well as the Songpan-Ganzi and Yangtze blocks in the past few decades, the knowledge of shallow thrust nappe tectonic along the belt has then been generally recognized. It's, however, still difficult to image the deep crust and mantle structures and reveal the dynamic mechanism of the crustal formation under the Longmen Mountain. In this study, we carried out the MT experiments along and across the Longmen mountain region and investigated the relationships between the crust structure and seismic activity basing on the latest MT geological results. 2. Field observations We conducted three MT experiment profiles in the eastern Tibetan Plateau. One is along the Mingshan-Guangyuan profile parallel with the structural direction, and another two profiles (Maqu-Gaoliangzhen and Luqu-Hechuan) perpendicular to the Longmen Mountain fault zone. In this study, we use the conventional magnetotelluric (MT) data combine with the long-period magnetotelluric (LMT) data to observe electromagnetic response. The MT and LMT data was observed by using the V8 instrument and LEMI-417, respectively. 3. Conclusion (1) According to the results of MT inversion, we find that the high concentration of stress process along the Songpan-Ganzi block and the Yangtze block colliding zone might result from the deep crust-mantle tough shear Zone of Longmen Mountain expanded to mid-upper crust, and finally leads to a new rupture. This could be one of the focal mechanisms of the Wenchuan earthquake (Ms 8.0) generating. The deep resistivity structure along the Longmen Mountain fault zone can be divided into southern,middle and northern segments from southwest to northeast. The total resistivity of southern segment is lower than the middle and northern portions. We suggest that the upper crust of the Longmen Mountain, south of Dayi

  6. Constrain the crust and upper mantle structure beneath the equatorial Eastern Pacific Rise from ambient noise and earthquake surface waves

    NASA Astrophysics Data System (ADS)

    Gao, C.; Yao, H.; Gouedard, P.; Collins, J. A.; McGuire, J. J.; van der Hilst, R.

    2012-12-01

    In this study we combine ambient noise and earthquake surface waves to jointly constrain the crust and upper mantle shear velocity structure beneath the equatorial eastern Pacific Rise using data from ocean bottom seismometers deployed in 2008. We measure the inter-station Rayleigh-wave phase velocity dispersion curves of the fundamental mode in the period band 2 - 30 s and the first higher mode in the period band 3 - 7 s from vertical component ambient noise cross-correlation functions. We also determine the inter-station phase velocity dispersion curves in the period band 20 - 100 s from an earthquake-based surface-wave two-station method. The average dispersion data from both ambient noise and earthquake surface waves are used to determine the average shear velocity structure in the crust and upper mantle using a global searching Neighborhood algorithm. Our results reveal a pronounced low velocity zone in the upper mantle with the shear wave speed as slow as 3.85 km/s beneath the equatorial eastern Pacific Rise, possibly caused by a combination of high temperature and the presence of partial melt beneath the mid-ocean ridges. We will also measure Love wave dispersion curves from transverse component ambient noise cross-correlation functions and earthquake surface waves. Together with Rayleigh-wave dispersion measurements, we will determine the radial anisotropy to constrain the deformation of the crust and upper mantle beneath the equatorial eastern Pacific Rise.

  7. Structures, microfabrics and textures of the Cordilleran-type Rechnitz metamorphic core complex, Eastern Alps☆

    PubMed Central

    Cao, Shuyun; Neubauer, Franz; Bernroider, Manfred; Liu, Junlai; Genser, Johann

    2013-01-01

    Rechnitz window group represents a Cordilleran-style metamorphic core complex, which is almost entirely located within nearly contemporaneous Neogene sediments at the transition zone between the Eastern Alps and the Neogene Pannonian basin. Two tectonic units are distinguished within the Rechnitz metamorphic core complex (RMCC): (1) a lower unit mainly composed of Mesozoic metasediments, and (2) an upper unit mainly composed of ophiolite remnants. Both units are metamorphosed within greenschist facies conditions during earliest Miocene followed by exhumation and cooling. The internal structure of the RMCC is characterized by the following succession of structure-forming events: (1) blueschist relics of Paleocene/Eocene age formed as a result of subduction (D1), (2) ductile nappe stacking (D2) of an ophiolite nappe over a distant passive margin succession (ca. E–W to WNW–ESE oriented stretching lineation), (3) greenschist facies-grade metamorphism annealing dominant in the lower unit, and (4) ductile low-angle normal faulting (D3) (with mainly NE–SW oriented stretching lineation), and (5) ca. E to NE-vergent folding (D4). The microfabrics are related to mostly ductile nappe stacking to ductile low-angle normal faulting. Paleopiezometry in conjunction with P–T estimates yield high strain rates of 10− 11 to 10− 13 s− 1, depending on the temperature (400–350 °C) and choice of piezometer and flow law calibration. Progressive microstructures and texture analysis indicate an overprint of the high-temperature fabrics (D2) by the low-temperature deformation (D3). Phengitic mica from the Paleocene/Eocene high-pressure metamorphism remained stable during D2 ductile deformation as well as preserved within late stages of final sub-greenschist facies shearing. Chlorite geothermometry yields two temperature groups, 376–328 °C, and 306–132 °C. Chlorite is seemingly accessible to late-stage resetting. The RMCC underwent an earlier large-scale coaxial

  8. Upper Mantle Discontinuity Structure Beneath the Western Atlantic Ocean and Eastern North America from SS Precursors

    NASA Astrophysics Data System (ADS)

    Schmerr, N. C.; Beghein, C.; Kostic, D.; Baldridge, A. M.; West, J. D.; Nittler, L. R.; Bull, A. L.; Montesi, L.; Byrne, P. K.; Hummer, D. R.; Plescia, J. B.; Elkins-Tanton, L. T.; Lekic, V.; Schmidt, B. E.; Elkins, L. J.; Cooper, C. M.; ten Kate, I. L.; Van Hinsbergen, D. J. J.; Parai, R.; Glass, J. B.; Ni, J.; Fuji, N.; McCubbin, F. M.; Michalski, J. R.; Zhao, C.; Arevalo, R. D., Jr.; Koelemeijer, P.; Courtier, A. M.; Dalton, H.; Waszek, L.; Bahamonde, J.; Schmerr, B.; Gilpin, N.; Rosenshein, E.; Mach, K.; Ostrach, L. R.; Caracas, R.; Craddock, R. A.; Moore-Driskell, M. M.; Du Frane, W. L.; Kellogg, L. H.

    2015-12-01

    Seismic discontinuities within the mantle arise from a wide range of mechanisms, including changes in mineralogy, major element composition, melt content, volatile abundance, anisotropy, or a combination of the above. In particular, the depth and sharpness of upper mantle discontinuities at 410 and 660 km depth are attributed to solid-state phase changes sensitive to both mantle temperature and composition, where regions of thermal heterogeneity produce topography and chemical heterogeneity changes the impedance contrast across the discontinuity. Seismic mapping of this topography and sharpness thus provides constraint on the thermal and compositional state of the mantle. The EarthScope USArray is providing unprecedented access to a wide variety of new regions previously undersampled by the SS precursors. This includes the boundary between the oceanic plate in the western Atlantic Ocean and continental margin of eastern North America. Here we use a seismic array approach to image the depth, sharpness, and topography of the upper mantle discontinuities, as well as other possible upper mantle reflectors beneath this region. This array approach utilizes seismic waves that reflect off the underside of a mantle discontinuity and arrive several hundred seconds prior to the SS seismic phase as precursory energy. In this study, we collected high-quality broadband data SS precursors data from shallow focus (< 30 km deep), mid-Atlantic ridge earthquakes recorded by USArray seismometers in Alaska. We generated 4th root vespagrams to enhance the SS precursors and determine how they sample the mantle. Our data show detection of localized structure on the discontinuity boundaries as well as additional horizons, such as the X-discontinuity and a potential reflection from a discontinuity near the depth of the lithosphere-asthenosphere boundary. These structures are related to the transition from predominantly old ocean lithosphere to underlying continental lithosphere, as while

  9. Yellowstone-Snake River Plain seismic profilling experiment: Crustal structure of the eastern Snake River Plain

    SciTech Connect

    Braile, L.W.; Smith, R.B.; Ansorge, J.; Baker, M.R.; Sparlin, M.A.; Prodehl, C.; Schilly, M.M.; Healy, J.H.; Mueller, S.; Olsen, K.H.

    1982-04-10

    Seismic refraction profiles recorded along the eastern Snake River Plain (ESRP) in southeastern Idaho during the 1978 Yellowstone-Snake River Plain cooperative seismic profiling experiment are interpreted to infer the crustal velocity and attenuation (Q-1) structure of the ESRP. Travel-time and synthetic seismogram modeling of a 250 km reversed refraction profile as well as a 100 km detailed profile indicate that the crust of the ESRP is highly anomalous. Approximately 3 to 6 km of volcanic rocks (with some interbedded sediments) overlie an upper-crustal layer (compressional velocity approx. =6.1 km/s) which thins southwestward along the ESRP from a thickness of 10 km near Island Park Caldera to 2 to 3 km beneath the central and southwestern portions of the ESRP. An intermediate-velocity (approx. =6.5 km/s) layer extends from approx. =10 to approx. =20 km depth. a thick (approx. =22 km) lower crust of compressional velocity 6.8 km/s, a total crustall thickness of approx. =42 km, and a P/sub n/ velocity of approx. =7.9 km/s is observed in the ESRP, similar to the western Snake River Plain and the Rocky Mountains Provinces. High attenuation is evident on the amplitude corrected seismic data due to low-Q values in the volcanic rocks (Q/sub p/ = 20 to 200) and throughout the crust (Q/sub p/ = 160 to 300). Based on these characteristics of the crustal structure and volcanic-age progression data, it is suggested that the ESRP has resulted from an intensitive period of intrusion of mantle-derived basaltic magma into the upper crust generating explosive silicic volcanism and associated regional uplift and caldera collapse. This activity began about 15 m.y. ago in southwestern Idaho and has migrated northeast to its present position at Yellowstone. Subsequent cooling of the intruded upper crust results in the 6.5 km/s velocity intermediate layer. Crustal subsidence and periodic basaltic volcanism as represented by the ESRP complete the sequence of crustal evolution.

  10. Structures, microfabrics and textures of the Cordilleran-type Rechnitz metamorphic core complex, Eastern Alps.

    PubMed

    Cao, Shuyun; Neubauer, Franz; Bernroider, Manfred; Liu, Junlai; Genser, Johann

    2013-11-26

    Rechnitz window group represents a Cordilleran-style metamorphic core complex, which is almost entirely located within nearly contemporaneous Neogene sediments at the transition zone between the Eastern Alps and the Neogene Pannonian basin. Two tectonic units are distinguished within the Rechnitz metamorphic core complex (RMCC): (1) a lower unit mainly composed of Mesozoic metasediments, and (2) an upper unit mainly composed of ophiolite remnants. Both units are metamorphosed within greenschist facies conditions during earliest Miocene followed by exhumation and cooling. The internal structure of the RMCC is characterized by the following succession of structure-forming events: (1) blueschist relics of Paleocene/Eocene age formed as a result of subduction (D1), (2) ductile nappe stacking (D2) of an ophiolite nappe over a distant passive margin succession (ca. E-W to WNW-ESE oriented stretching lineation), (3) greenschist facies-grade metamorphism annealing dominant in the lower unit, and (4) ductile low-angle normal faulting (D3) (with mainly NE-SW oriented stretching lineation), and (5) ca. E to NE-vergent folding (D4). The microfabrics are related to mostly ductile nappe stacking to ductile low-angle normal faulting. Paleopiezometry in conjunction with P-T estimates yield high strain rates of 10(- 11) to 10(- 13) s(- 1), depending on the temperature (400-350 °C) and choice of piezometer and flow law calibration. Progressive microstructures and texture analysis indicate an overprint of the high-temperature fabrics (D2) by the low-temperature deformation (D3). Phengitic mica from the Paleocene/Eocene high-pressure metamorphism remained stable during D2 ductile deformation as well as preserved within late stages of final sub-greenschist facies shearing. Chlorite geothermometry yields two temperature groups, 376-328 °C, and 306-132 °C. Chlorite is seemingly accessible to late-stage resetting. The RMCC underwent an earlier large-scale coaxial deformation

  11. The antifreeze potential of the spruce budworm thermal hysteresis protein.

    PubMed

    Tyshenko, M G; Doucet, D; Davies, P L; Walker, V K

    1997-09-01

    Antifreeze proteins (AFP) inhibit ice growth by surface adsorption that results in a depression of the freezing point below the melting point. The maximum level of this thermal hysteresis shown by the four structurally unrelated fish AFP is approximately 1.5 degrees C. In contrast, hemolymph and crude extracts from insects can have 5 degrees to 10 degrees C of thermal hysteresis. Based on the isolation, cloning, and expression of a thermal hysteresis protein (THP) from spruce budworm (Choristoneura fumiferana), the vastly greater activity is attributable to a 9 kDa protein. This novel, threonine- and cysteine-rich THP has striking effects on ice crystal morphology, both before and during freezing. It is also 10 to 30 times more active than any known fish AFP, offering the prospect of superior antifreeze properties in cryoprotective applications.

  12. Geology of the Plumtree area, Spruce Pine district, North Carolina

    USGS Publications Warehouse

    Brobst, Donald Albert

    1953-01-01

    This report describes the results of study and geologic mapping (1:12,000) in the 70-square-mile Plumtree area in the northeastern part of the Spruce Pine pegmatite district, on the Blue Ridge upland in western North Carolina. The district has been the chief domestic source of feldspar and sheet mica. The mining belt just west of the Blue Ridge Front trends northeast and is 25 miles long and 10 miles wide. The center of the Plumtree area lies 10 miles northeast of Spruce Pine pegmatite district, on the Blue Ridge upland in western North Carolina. The district has been the chief domestic source of feldspar and sheet mica. The mining belt just west of the Blue Ridge Front trends northeast and is 25 miles long and 10 miles wide. The center of the Plumtree area lies 10 miles northeast of Spruce Pine and includes parts of Mitchell and Avery Counties shown on the portions of the 7.5-minute Spruce Pine, Linville Falls, Newland, North Carolina, and Carvers Gap, North Carolina and Tennessee quadrangle. The topography varies from rugged mountains to rounded or flat topped hills near the entrenched, meandering master streams. Old erosion surfaces are approximately 600,1,100, 1,500, and 2,500 feet above the present master stream level. The area is in late youth or early maturity after rejuvenation.. The regionally metamorphosed rocks of the amophibolite facies form three mappable units: mica gneiss, mica schist, and hornblende rock. These rocks, perhaps of Precambrian age, are intimately interlayered with thicknesses of the individual layers ranging from less than one inch to several tons of feet. Field relationships and chemical data suggest that the mica (Carolina-type) rocks were derived from sandstones, graywackes, and shales and that the hornblende-rich (Roan-type) layers were derived from impure carbonate rocks. The igneous rocks include alaskite and associated pegmatite of early Paleozoic age (?), dunite and associated soapstone of a prepegmatite age, and a few diabasic

  13. Gravity field and structure of the Sorong Fault Zone, eastern Indonesia

    NASA Astrophysics Data System (ADS)

    Sardjono

    Gravity surveys along coastlines of islands in the region Banggai-Sula, Eastern Sulawesi, Halmahera, Bacan and Obi were carried out as part of the Sorong Fault Zone Project. Results of the Surveys were integrated with gravity data previously acquired by other projects, including on-land gravity data from the Bird Head area Irian Jaya (Dow et al 1986), Seram Island (Milsom 1977), Buru Island (Oemar and Reminton 1993) and Central Sulawesi (Silver et al. 1983) as well as marine gravity information within and surrounding the Sorong Fault Zone (Bowin et al. 1980). Gravity expeditions of the Sorong Fault Zone Project also include measurements in Mayu Island and the island group of Talaud, situated further north in the Central Molucca Sea region. A total of one hundred and forty two gravity data were acquired in the region of Banggai-Sula islands, forty seven in eastern part of Central Sulawesi, about four hundred in Halmahera, Bacan and Obi, and seventy nine in Mayu and Talaud. Surveys in the eastern part of Central Sulawesi were carried out for the purpose of tieing the older gravity data obtained from Silver et al. (1983) and the more recent data of the Sorong Fault Zone Project. About one thousand thirty hundred and thirty gravity data were acquired as part of the Irian Jaya Geological Mapping Project (IJGMP) in the period of 1978-1983, a project commissioned by the Indonesian Geological Research and Development Centre (GRDC) and the Australian Bureau of Mineral Resources (BMR). The remoteness of the survey areas of the Sorong Fault Zone Project necessitated a careful planning for travel arrangements and provision of logistics. A wide range of magnitude of gravity field was observed in the Sorong Fault Zone, extending from values below -250 mGal recorded in the southern part of the Molucca Sea to values in excess of +320 mGal measured near to sea level in the coastal areas south of Mangole and north of Sulabesi, the two islands of the Sula Group. Steep gradients of

  14. "Super" Spruce Seedlings Continue Superior Growth for 18 Years

    Treesearch

    Hans Nienstaedt

    1981-01-01

    White spruce seedlings--20, 19, 18, and 17 inches tall--were selected among 2-2 transplants; controls from the same beds averaged 7.7 inches tall. After 18 years in the field, the selected seedlings continued to have a 30 percent height growth advantage over the controls. This note discusses how to incorporate super spruce seedlings into a tree breeding program....

  15. Some observations on age relationships in spruce-fir regeneration

    Treesearch

    Barton M. Blum

    1973-01-01

    Measurement of the ages of seedlings of balsam fir (Abies balsamea (L) Mill.), red spruce (Picea rubens Sarg.), and white spruce (Picea glauca (Moench) Voss) 15 years after the first harvest of a two-cut shelterwood operation revealed that very few potential crop-tree seedlings in the sample occurred as advance...

  16. Status of viruses as biocontrol agents for spruce budworms

    Treesearch

    J. C. Cunningham

    1985-01-01

    Aerial spray trials with a variety of viruses have been conducted between 1971 and 1983 with 2656 ha (65 plots) treated to control spruce budworm in Ontario and Quebec and 424 ha (6 plots) treated to control western spruce budworm in British Columbia. Generally, results have been inconsistent and less than satisfactory, but research continues in an effort to develop a...

  17. Analyses of Great Smoky Mountain Red Spruce Tree Ring Data

    Treesearch

    Paul C. van Deusen; [Editor

    1988-01-01

    Four different analyses of red spruce tree ring data from the Great Smoky Mountains are presented along with a description of the spruce/fir ecosystem.The analyses use several techniques including spatial analysis, fractals, spline detrending, and the Kalman filter.

  18. Spruce reproduction dynamics on Alaska's Kenai Peninsula, 1987-2000.

    Treesearch

    Willem W.S. van Hees

    2005-01-01

    During the past 30 years, spruce forests of Alaska’s Kenai Peninsula have undergone dramatic changes resulting from widespread spruce bark beetle(Dendroctonus rufipennis (Kirby)) infestation. In 1987 and again in 2000, the Pacific Northwest Research Station's Forest Inventory and Analysis Program conducted initial and remeasurement inventories...

  19. Preliminary lumber recovery for dead and live Engelmann spruce.

    Treesearch

    James M. Cahill

    1980-01-01

    Lumber recovery, lumber grade distribution, and log values are presented for logs cut from dead and live Engelmann spruce (Picea engelmannii Parry ex Engelm.) trees. The dead sample includes standing and down trees killed by the Engelmann spruce beetle (Dendroctonus ruffipennis Kirby) over 20 years ago.

  20. Computer simulation for integrated pest management of spruce budworms

    Treesearch

    Carroll B. Williams; Patrick J. Shea

    1982-01-01

    Some field studies of the effects of various insecticides on the spruce budworm (Choristoneura sp.) and their parasites have shown severe suppression of host (budworm) populations and increased parasitism after treatment. Computer simulation using hypothetical models of spruce budworm-parasite systems based on these field data revealed that (1)...

  1. SPRUCE Discovery Manual, 169 Investigations Indoors and Outdoors.

    ERIC Educational Resources Information Center

    Busch, Phyllis S.

    Contained are instructional materials developed by the Science Project Related to Upgrading Conservation Education ("SPRUCE"). It is designed for use with the SPRUCE "Discovery Box" and contains twenty-one sets of investigations based on the twenty-one packets of specimens in the box; three sets are recommended for each of…

  2. Fertilization of black spruce or poor site peatland in Minnesota.

    Treesearch

    David H. Alban; Richard F. Watt

    1981-01-01

    Fertilization of poor site black spruce on organic soil with various rates of nitrogen and phosphorus increased height and diameter growth from 2 to 4 times. The growth response declined with time but was still apparent 16 years after fertilization. Shrub biomass and coverage, and nutrient levels of spruce foliage were strongly affected by fertilization.

  3. Kinematics, crustal structure and seismotectonics of the subducting northernmost Luzon arc in eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Lee, Jian-Cheng; Chen, Chia-Yu; Chen, Rou-Fei; Chen, Yue-Gau; Chen, Horng-Yue

    2015-04-01

    The Coastal Range in eastern Taiwan belongs to the northernmost Luzon arc system, which sits on the western edge of the NW-moving Philippine Sea plates (PSP). As the PSP subducting and colliding with the Eurasian continental margin in Taiwan, the northern part of the Coastal Range provides a crucial key for better understand the geological structures and processes at tectonic transition from collision to subduction at plate corner. In this study, we conducted a dense network of GPS measurements at the northern tip of the Coastal Range and compiled available geological and geophysical information, including surface geomorphic features, geological structures, seismological data, seismic tomography, in order to provide insights on kinematics, crustal structure and seismotectonics of the transition from waning collision to subduction of the northern Luzon arc system and its vicinity. Regional short-term geodetic data, including GPS and levelling, and long-term thousand-year scale geological vertical rates indicate that the Coastal Range is going down toward the north, which we interpret it as being pulling down by the north- subduction PSP. Combing with the local GPS measurements carried out at the northern tip of the Longitudinal Valley, the plate suture, which shows a significant clockwise rotation at a rate of 33° M/yr, we interpret the tectonic escape of the northernmost Longitudinal Valley as being initiated locally by the northwest indentation of the Coastal Range, which pushed the northern Longitudinal Valley to move upward and eastward to form a 2-km-wide, 8-km-long, 100-m-high Milun Tableland. No significant deformation was observed across the surface trace of the major active Milun fault on the western side of the tableland, which has been ruptured during the 1951 M=7.1 Hualien earthquake, indicating that the Milun fault is now probably locked in the near surface. As for the crustal structure, we anticipate that there exists a fore-arc basement of the Luzon

  4. The Structural Disempowerment of Eastern European Migrant Farm Workers in Norwegian Agriculture

    ERIC Educational Resources Information Center

    Rye, Johan Fredrik; Andrzejewska, Joanna

    2010-01-01

    Since the 2004 EU enlargement established one European common labour market, a large number of Eastern Europeans have taken up seasonal employment as hired farm workers in Norwegian agriculture. Much attention in the public has been given to the potential for "social dumping" of these migrating workers, as they are considered prone to…

  5. Structural Dimensions of Roma School Desegregation Policies in Central and Eastern Europe

    ERIC Educational Resources Information Center

    Rostas, Iulius; Kostka, Joanna

    2014-01-01

    Scrutiny of the socio-economic exclusion of the Roma in Central and Eastern Europe has brought attention to the widespread practice of school segregation of Romani children who are automatically placed in classes for the mentally disabled or shunted into separate and inferior schools and classrooms. It is now widely recognised that such practices…

  6. The Structural Disempowerment of Eastern European Migrant Farm Workers in Norwegian Agriculture

    ERIC Educational Resources Information Center

    Rye, Johan Fredrik; Andrzejewska, Joanna

    2010-01-01

    Since the 2004 EU enlargement established one European common labour market, a large number of Eastern Europeans have taken up seasonal employment as hired farm workers in Norwegian agriculture. Much attention in the public has been given to the potential for "social dumping" of these migrating workers, as they are considered prone to…

  7. Composition, structure, and sustainability of hemlock ecosystems in eastern North America

    Treesearch

    William H. McWilliams; Thomas L. Schmidt

    2000-01-01

    Across its natural range in North America, eastern hemlock (Tsuga Canadensis (L.) Carriere) is an important resource for people and wildlife, but it is seriously threatened by the hemlock woolly adelgid (HWA) (Adelges tsugae Annand). From 10 to 20 percent of the hemlock resource is found in the Canadian provinces of New Brunswick,...

  8. Structural Dimensions of Roma School Desegregation Policies in Central and Eastern Europe

    ERIC Educational Resources Information Center

    Rostas, Iulius; Kostka, Joanna

    2014-01-01

    Scrutiny of the socio-economic exclusion of the Roma in Central and Eastern Europe has brought attention to the widespread practice of school segregation of Romani children who are automatically placed in classes for the mentally disabled or shunted into separate and inferior schools and classrooms. It is now widely recognised that such practices…

  9. Rift Structure along the Eastern Continental Margin of India - new constraints on style of breakup of the Indian landmass from the eastern Gondwanaland

    NASA Astrophysics Data System (ADS)

    Ismaiel, M.; Krishna, K. S.; Karlapati, S.; Mishra, J.; D, S.

    2015-12-01

    The Eastern Continental Margin of India (ECMI), a classical passive margin has evolved after breakup of the Indian landmass from the East Antarctica during the Early Cretaceous. Anomalous thick sediments and lack of cohesive magnetic signatures in the Bay of Bengal hampered delineation of rift-structure and age assignment for the continental breakup between India and East Antarctica. Further, absence of lithological and geochronological information and a few seismic profiles from the margin led to put forward several competing models for the rift initiation and evolution of the ECMI. Here, we analyze long streamer seismic reflection data and deep-water drill well information from the western Bay of Bengal to infer the buried rift structure, crustal architecture and stratigraphy along the ECMI. Following the structural pattern of the margin, the region is divided into four domains as decoupled, coupled, exhumed and oceanic, which in turn helped us to demarcate the variations in rift structure from south to north along the margin. The southern segment in the vicinity of Cauvery Basin consists of steep continental shelf associated with few major normal faults, which indicates that the segment was evolved as mix shear-rifted margin. The central segment off southern part of the Krishna-Godavari Basin is controlled by a series of fault-bounded half-graben structures and presence of thinned continental crust over the exhumed mantle body, revealing that the segment was formed under hyper-rifting process. While the northern segment extends up to Mahanadi Basin shows relatively less gradient continental slope with a few major faults, suggesting that the segment was evolved by hypo-extended process. Variable crustal architecture lying along the ECMI supports each segment of the margin formed in a specific rift process. A breakup unconformity considered as important geological constraint for completion of rift process between India and East Antarctica is clearly mapped on

  10. Factors influencing northern spruce engraver colonization of white spruce slash in interior Alaska

    Treesearch

    Christopher J. Fettig; Roger E. Burnside; Chistopher J. Hayes; James J. Kruse; Nicholas J. Lisuzzo; Stephen R. McKelvey; Sylvia R. Mori; Stephen K. Nickel; Mark E. Schultz

    2013-01-01

    In interior Alaska, increased use of mechanical fuel reduction treatments, increased interests in the use of wood energy systems as alternatives to fossil fuels, and elevated populations of northern spruce engraver, Ips perturbatus (Eichhoff), have raised concerns regarding the impact of this bark beetle to forest resources. We conducted a large-...

  11. Mapping vulnerability of spruce-fir stands in the Northeast to spruce budworm attack

    Treesearch

    Thomas F. McLintock

    1949-01-01

    Once again a spruce budworm epidemic threatens to destroy large volumes of timber in the Northeast. One defense against the budworm is to cut and utilize trees in those stands in which the budworms are most apt to feed and breed. In this report the author presents three practical methods of determining what trees or stands should be cut first.

  12. Stand structural diversity rather than species diversity enhances aboveground carbon storage in secondary subtropical forests in Eastern China

    NASA Astrophysics Data System (ADS)

    Ali, Arshad; Yan, En-Rong; Chen, Han Y. H.; Chang, Scott X.; Zhao, Yan-Tao; Yang, Xiao-Dong; Xu, Ming-Shan

    2016-08-01

    Stand structural diversity, typically characterized by variances in tree diameter at breast height (DBH) and total height, plays a critical role in influencing aboveground carbon (C) storage. However, few studies have considered the multivariate relationships of aboveground C storage with stand age, stand structural diversity, and species diversity in natural forests. In this study, aboveground C storage, stand age, tree species, DBH and height diversity indices, were determined across 80 subtropical forest plots in Eastern China. We employed structural equation modelling (SEM) to test for the direct and indirect effects of stand structural diversity, species diversity, and stand age on aboveground C storage. The three final SEMs with different directions for the path between species diversity and stand structural diversity had a similar goodness of fit to the data. They accounted for 82 % of the variation in aboveground C storage, 55-59 % of the variation in stand structural diversity, and 0.1 to 9 % of the variation in species diversity. Stand age demonstrated strong positive total effects, including a positive direct effect (β = 0.41), and a positive indirect effect via stand structural diversity (β = 0.41) on aboveground C storage. Stand structural diversity had a positive direct effect on aboveground C storage (β = 0.56), whereas there was little total effect of species diversity as it had a negative direct association with, but had a positive indirect effect, via stand structural diversity, on aboveground C storage. The negligible total effect of species diversity on aboveground C storage in the forests under study may have been attributable to competitive exclusion with high aboveground biomass, or a historical logging preference for productive species. Our analyses suggested that stand structural diversity was a major determinant for variations in aboveground C storage in the secondary subtropical forests in Eastern China. Hence, maintaining tree DBH and

  13. Low temperature thermochronology in the Eastern Alps: Implications for structural and topographic evolution

    PubMed Central

    Wölfler, Andreas; Stüwe, Kurt; Danišík, Martin; Evans, Noreen J.

    2012-01-01

    According to new apatite fission track, zircon- and apatite (U–Th)/He data, we constrain the near-surface history of the southeastern Tauern Window and adjacent Austrolapine units. The multi-system thermochronological data demonstrate that age-elevation correlations may lead to false implications about exhumation and cooling in the upper crust. We suggest that isothermal warping in the Penninic units that are in the position of a footwall, is due to uplift, erosion and the buildup of topography. Additionally we propose that exhumation rates in the Penninic units did not increase during the Middle Miocene, thus during the time of lateral extrusion. In contrast, exhumation rates of the Austroalpine hangingwall did increase from the Paleogene to the Neogene and the isotherms in this unit were not warped. The new zircon (U–Th)/He ages as well as zircon fission track ages from the literature document a Middle Miocene exhumation pulse which correlates with a period of enhanced sediment accumulation during that time. However, enhanced sedimentation- and exhumation rates at the Miocene/Pliocene boundary, as observed in the Western- and Central Alps, cannot be observed in the Eastern Alps. This contradicts a climatic trigger for surface uplift, and makes a tectonic trigger and/or deep-seated mechanism more obvious to explain surface uplift in the Eastern Alps. In combination with already published geochronological ages, our new data demonstrate Oligocene to Late Miocene fault activity along the Möll valley fault that constitutes a major shear zone in the Eastern Alps. In this context we suggest a geometrical and temporal relationship of the Katschberg-, Polinik–Möll valley- and Mur–Mürz faults that define the extruding wedge in the eastern part of the Eastern Alps. Equal deformation- and fission track cooling ages along the Katschberg–Brenner- and Simplon normal faults demonstrate overall Middle Miocene extension in the whole alpine arc. PMID:27065501

  14. Low temperature thermochronology in the Eastern Alps: Implications for structural and topographic evolution.

    PubMed

    Wölfler, Andreas; Stüwe, Kurt; Danišík, Martin; Evans, Noreen J

    2012-05-14

    According to new apatite fission track, zircon- and apatite (U-Th)/He data, we constrain the near-surface history of the southeastern Tauern Window and adjacent Austrolapine units. The multi-system thermochronological data demonstrate that age-elevation correlations may lead to false implications about exhumation and cooling in the upper crust. We suggest that isothermal warping in the Penninic units that are in the position of a footwall, is due to uplift, erosion and the buildup of topography. Additionally we propose that exhumation rates in the Penninic units did not increase during the Middle Miocene, thus during the time of lateral extrusion. In contrast, exhumation rates of the Austroalpine hangingwall did increase from the Paleogene to the Neogene and the isotherms in this unit were not warped. The new zircon (U-Th)/He ages as well as zircon fission track ages from the literature document a Middle Miocene exhumation pulse which correlates with a period of enhanced sediment accumulation during that time. However, enhanced sedimentation- and exhumation rates at the Miocene/Pliocene boundary, as observed in the Western- and Central Alps, cannot be observed in the Eastern Alps. This contradicts a climatic trigger for surface uplift, and makes a tectonic trigger and/or deep-seated mechanism more obvious to explain surface uplift in the Eastern Alps. In combination with already published geochronological ages, our new data demonstrate Oligocene to Late Miocene fault activity along the Möll valley fault that constitutes a major shear zone in the Eastern Alps. In this context we suggest a geometrical and temporal relationship of the Katschberg-, Polinik-Möll valley- and Mur-Mürz faults that define the extruding wedge in the eastern part of the Eastern Alps. Equal deformation- and fission track cooling ages along the Katschberg-Brenner- and Simplon normal faults demonstrate overall Middle Miocene extension in the whole alpine arc.

  15. Development of White and Norway Spruce Trees from Several Seed Sources 29 Years After Planting

    Treesearch

    James P. King; Paul O. Rudolf

    1969-01-01

    A 29-year-old test of trees grown from seven white spruce and six Norway spruce seed sources and planted in Wisconsin and Minnesota demonstrates the importance of seed-source selection and indicates that trees from some Norway spruce sources equal or surpass the native white spruce.

  16. Analyses of Great Smoky Mountain red spruce tree-ring data. Forest Service general technical report

    SciTech Connect

    Van Deusen, P.C.

    1988-05-01

    Contents include: Southern Appalachian Red Spruce--Fraser Fir Forests; A tree ring analysis of Red Spruce in the Southern Appalachian Mountains; Utilizing time series models and spatial analysis of forecast residuals for tree-ring analysis of Red Spruce; A fractal approach to analysis of tree-ring increments; Red Spruce Tree Ring Analysis using a Kalman Filter.

  17. Putting community data to work: some understory plants indicate red spruce regeneration habitat

    Treesearch

    Alison C. Dibble; John C. Brissette; Malcolm L. Hunter

    1999-01-01

    When harvested, red spruce (Picea rubens) at low elevations is vulnerable to temporary displacement by balsam fir (Abies balsamea) and hardwoods. If indicator plants can be found by which to assess spruce regeneration habitat, then biota dependent on red spruce dominance could benefit. Associations between spruce seedlings (0.1-0.5...

  18. Managing white and Lutz spruce stands in south-central Alaska for increased resistance to spruce beetle.

    Treesearch

    J.S. Hard; E.H. Holsten

    1985-01-01

    Thinning is recommended for maintaining vigorous tree growth to minimize losses caused by spruce beetles (Dendroctonus rufipenni Kirby) and windthrow in residual stands of spruce in south-central Alaska. The anatomy of conifer stems, the variation in stem diameter growth, and the variability of tree response to wounding are discussed to explain why...

  19. Regionalization of Crustal and Upper Mantle Q Structure in Eastern Eurasia Using Multiple Regional Waves

    DTIC Science & Technology

    2007-02-05

    ABSTRACT We have mapped lateral variations in seismic Q in eastern Eurasia, including continental China, central Asia, Mongolia and Siberia, using...China. 3Department of Geology and Geophysics, University of Wisconsin- Madison, Madison, Wisconsin, USA. Copyright 2006 by the American Geophysical...Department of Geology and Geophysics, University of Wisconsin-Madison, 1215 W. Dayton St., Madison, WI 53706, USA. (yunfengl@geology.wisc.edu) D. Schaff

  20. Skate assemblage on the eastern Patagonian Shelf and Slope: structure, diversity and abundance.

    PubMed

    Arkhipkin, A; Brickle, P; Laptikhovsky, V; Pompert, J; Winter, A

    2012-04-01

    The eastern Patagonian Shelf and continental slope of the south-west Atlantic Ocean support a high biodiversity and abundance of skates. In this study, meso-scale differences in the assemblages, spatial and seasonal distributions of skates are revealed among six habitat zones of the eastern Patagonian Shelf characterized by distinctive oceanographic conditions. Most skates belonged to temperate fauna, and their abundance was much greater in habitats occupied by temperate waters (north-western outer shelf) or mixed waters (northern slope) than in habitats occupied by sub-Antarctic waters (SASW) (south-eastern outer shelf and southern slope). Sub-Antarctic skates were not abundant on the shelf even in habitats occupied by SASW, occurring mainly in deep areas of the lower continental slope. The majority of temperate skates migrated seasonally, shifting northward in winter and spreading southward with warming waters in summer. Most temperate species had two peaks in female maturity (mainly spring and autumn) and spawned in the same habitats where they fed. It is hypothesized that the high biodiversity and abundance of skates on the Patagonian Shelf and Slope are due to the practical absence of their natural competitors, flatfishes, which occupy similar eco-niches elsewhere.

  1. Structural coloration signals condition, parental investment, and circulating hormone levels in Eastern bluebirds (Sialia sialis).

    PubMed

    Grindstaff, Jennifer L; Lovern, Matthew B; Burtka, Jennifer L; Hallmark-Sharber, Alesia

    2012-08-01

    Many of the brilliant plumage coloration displays of birds function as signals to conspecifics. One species in which the function of plumage ornaments has been assessed is the Eastern bluebird (Sialia sialis). Studies of a population breeding in Alabama (USA) have established that plumage ornaments signal quality, parental investment, and competitive ability in both sexes. Here we tested the additional hypotheses that (1) Eastern bluebird plumage ornamentation signals nest defense behavior in heterospecific competitive interactions and (2) individual variation in plumage ornamentation reflects underlying differences in circulating hormone levels. We also tested the potential for plumage ornaments to signal individual quality and parental investment in a population breeding in Oklahoma (USA). We found that Eastern bluebirds with more ornamented plumage are in better condition, initiate breeding earlier in the season, produce larger clutches, have higher circulating levels of the stress hormone corticosterone, and more ornamented males have lower circulating androgen levels. Plumage coloration was not related to nest defense behavior. Thus, plumage ornamentation may be used by both sexes to assess the physiological condition and parental investment of prospective mates. Experimental manipulations of circulating hormone levels during molt are needed to define the role of hormones in plumage ornamentation.

  2. Orogen-perpendicular structures in the central Tasmanides and implications for the Paleozoic tectonic evolution of eastern Australia

    NASA Astrophysics Data System (ADS)

    Abdullah, Rashed; Rosenbaum, Gideon

    2017-01-01

    The curvilinear E-W structures of the southern Thomson Orogen are approximately orthogonal to the general N-S structural trend of the Tasmanides of eastern Australia. The origin of these orogen-perpendicular structures and their implications to tectonic reconstructions of eastern Gondwana are not fully understood. Here we use geophysical data to unravel the geometry, kinematics and possible timing of major structures along the boundary between the Thomson Orogen and the southern Tasmanides (Delamerian and Lachlan orogens). Aeromagnetic data from the southern Thomson Orogen show WNW, E-W and/or ENE trending structural grains, corresponding to relatively long wavelength linear geophysical anomalies. Kinematic analyses indicate strike-slip and transpressional deformation along these geophysically defined faults. Structural relationships indicate that faulting took place during the Benambran (Late Ordovician to Middle Silurian) and Tabberabberan (late Early to Middle Devonian) orogenies. However, some of the described crustal-scale structures may have developed in the Cambrian during the Delamerian Orogeny. Interpretation of deep seismic data shows that the crust of the southern Thomson Orogen is substantially thicker than the Lachlan Orogen crust, which is separated from the Thomson Orogen by the north-dipping Olepoloko Fault. A major lithospheric-scale change across this boundary is also indicated by a contrast in seismic velocities. Together with evidence for the occurrence of Delamerian deformation in both the Koonenberry Belt and northeastern Thomson Orogen, and a significant contrast in the width of the northern Tasmanides versus the southern Tasmanides, it appears that the southern Thomson Orogen may represent the locus of orogen-perpendicular segmentation, which may have occurred in response to along-strike plate boundary variations.

  3. Total OH reactivity emissions from Norway spruce

    NASA Astrophysics Data System (ADS)

    Nölscher, Anke; Bourtsoukidis, Efstratios; Bonn, Boris; Kesselmeier, Jürgen; Lelieveld, Jos; Williams, Jonathan

    2013-04-01

    Forest emissions represent a strong potential sink for the main tropospheric oxidant, the hydroxyl radical (OH). In forested environments, the comparison of the directly determined overall sink of OH radicals, the total OH reactivity, and the individually measured OH sink compounds often exposes a significant gap. This "missing" OH reactivity can be high and influenced by both direct biogenic emissions and secondary photo-oxidation products. To investigate the source of the missing OH sinks in forests, total OH reactivity emission rates were determined for the first time from a Norway spruce (Picea abies) throughout spring, summer and autumn 2011. The total OH reactivity was measured inside a branch enclosure using the Comparative Reactivity Method (CRM) with a Proton Transfer Reaction-Mass Spectrometer (PTR-MS) as the detector. In parallel, separate volatile organic compounds (VOC) emission rates were monitored by a second PTR-MS, including the signal of isoprene, acetaldehyde, total monoterpenes and total sesquiterpenes. The comparison of known and PTR-MS detected OH sink compounds and the directly measured total OH reactivity emitted from Norway spruce revealed unmeasured and possibly unknown primary biogenic emissions. These were found to be highest in late summer during daytime coincident with highest temperatures and ozone levels.

  4. [Richard Spruce, botanist-South America's explorer].

    PubMed

    Seaward, M R

    2000-01-01

    Between 1849 and 1864, the English botanist and explorer Richard Spruce carried out a detailed study of the Amazon flora and the costumes of the peoples who inhabited the region. To date a large part of the existing knowledge about several botanical families in the region stems from this scientist's efforts. His comprehensive interests, his detailed and precise descriptions were outstanding: nothing seems to have been left out of his scrutiny and recording aptitude. Not only was Spruce a remarkable botanist but he was also a distinctive anthropologist, linguist (he knew French, Spanish and Portuguese), geologist and geographer, as well as an acute sociological observer of the political systems and habits of the Amazonian and Andean trips in which has has been. He could thus make a considerable contribution to the understanding of indigenous beliefs and practices, as well as to the knowledge and uses of plants within the Amazonian context. Also important was his participation in the economic exploration of local species, particularly as regards the Hevea and the Cinchona genera.

  5. Structural differences between the western and eastern Qiongdongnan Basin: evidence of Indochina block extrusion and South China Sea seafloor spreading

    NASA Astrophysics Data System (ADS)

    Zhang, Cuimei; Wang, Zhenfeng; Sun, Zhipeng; Sun, Zhen; Liu, Jianbao; Wang, Zhangwen

    2013-12-01

    Located at the intersection between a NW-trending slip system and NE-trending rift system in the northern South China Sea, the Qiongdongnan Basin provides key clues for us to understand the proposed extrusion of the Indochina Block along with Red River Fault Zone and extensional margins. In this paper we for the first time systematically reveal the striking structural differences between the western and eastern sector of the Qiongdongnan Basin. Influenced by the NW-trending slip faults, the western Qiongdongnan Basin developed E-W-trending faults, and was subsequently inverted at 30-21 Ma. The eastern sector was dominated by faults with NE orientation before 30 Ma, and thereafter with various orientations from NE, to EW and NW during the period 30-21 Ma; rifting display composite symmetric graben instead of the composite half graben or asymmetric graben in the west. The deep and thermal structures in turn are invoked to account for such deformation differences. The lithosphere of the eastern Qiongdongnan Basin is very hot and thinned because of mantle upwelling and heating, composite symmetric grabens formed and the faults varied with the basal plate boundary. However, the Southern and Northern Uplift area and middle of the central depression is located on normal lithosphere and formed half grabens or simple grabens. The lithosphere in the western sector is transitional from very hot to normal. Eventually, the Paleogene tectonic development of the Qiongdongnan Basin may be summarized into three stages with dominating influences, the retreat of the West Pacific subduction zone (44-36 Ma), slow Indochina block extrusion together with slab-pull of the Proto-South China Sea (36-30 Ma), rapid Indochina block extrusion together with the South China Sea seafloor spreading (30-21 Ma).

  6. Status of the spruce; Fir cooperative research program

    SciTech Connect

    Hertel, G.D.; Zarnoch, S.J.; Arre, T. ); Eager, C. ); Mohnen, V. ); MedLarz, S. )

    1987-01-01

    Aside from the mixed conifer forest in the San Bernadino National Forest near the Los Angeles Basin, the only significant visible decline and mortality of a U.S. forest possibly caused by regional air pollution is found in the high elevation spruce/fir forests of the Appalachians (VA, NC, TN, W VA), Adirondacks (NY), Green Mountains (VT), and the White Mountains (NH). In January, most of the scientists that have or are currently studying Spruce-Fir conditions met in Philadelphia. They came to a consensus on the regional condition of the Spruce-Fir forests. The results of that meeting are summarized.

  7. [Structure of the gene pool of eastern Ukrainians from Y-chromosome haplogroups].

    PubMed

    Khar'kov, V N; Stepanov, V A; Borinskaia, S A; Kozhekbaeva, Zh M; Gusar, V A; Grechanina, E Ia; Puzyrev, V P; Khusnutdinova, E K; Iankovskiĭ, N K

    2004-03-01

    Y chromosomes from representative sample of Eastern Ukrainians (94 individuals) were analyzed for composition and frequencies of haplogroups, defined by 11 biallelic loci located in non-recombining part of the chromosome (SRY1532, YAP, 92R7, DYF155S2, 12f2, Tat, M9, M17, M25, M89, and M56). In the Ukrainian gene, pool six haplogroups were revealed: E, F (including G and I), J, N3, P, and R1a1. These haplogroups were earlier detected in a study of Y-chromosome diversity on the territory of Europe as a whole. The major haplogroup in the Ukrainian gene pool, haplogroup R1a1 (earlier designated HG3), accounted for about 44% of all Y chromosomes in the sample examined. This haplogroup is thought to mark the migration patterns of the early Indo-Europeans and is associated with the distribution of the Kurgan archaeological culture. The second major haplogroup is haplogroup F (21.3%), which is a combination of the lineages differing by the time of appearance. Haplogroup P found with the frequency of 9.6%, represents the genetic contribution of the population originating from the ancient autochthonous population of Europe. Haplogroups J and E (11.7 and 4.2%, respectively) mark the migration patterns of the Middle-Eastern agriculturists during the Neolithic. The presence of the N3 lineage (9.6%) is likely explained by a contribution of the assimilated Finno-Ugric tribes. The data on the composition and frequencies of Y-chromosome haplogroups in the sample studied substantially supplement the existing picture of the male lineage distribution in the Eastern Slav population.

  8. The Genetic Structure of Wild Orobanche cumana Wallr. (Orobanchaceae) Populations in Eastern Bulgaria Reflects Introgressions from Weedy Populations

    PubMed Central

    Pineda-Martos, Rocío; Pujadas-Salvà, Antonio J.; Fernández-Martínez, José M.; Stoyanov, Kiril; Pérez-Vich, Begoña

    2014-01-01

    Orobanche cumana is a holoparasitic plant naturally distributed from central Asia to south-eastern Europe, where it parasitizes wild Asteraceae species. It is also an important parasitic weed of sunflower crops. The objective of this research was to investigate genetic diversity, population structure, and virulence on sunflower of O. cumana populations parasitizing wild plants in eastern Bulgaria. Fresh tissue of eight O. cumana populations and mature seeds of four of them were collected in situ on wild hosts. Genetic diversity and population structure were studied with SSR markers and compared to weedy populations. Two main gene pools were identified in Bulgarian populations, with most of the populations having intermediate characteristics. Cross-inoculation experiments revealed that O. cumana populations collected on wild species possessed similar ability to parasitize sunflower to those collected on sunflower. The results were explained on the basis of an effective genetic exchange between populations parasitizing sunflower crops and those parasitizing wild species. The occurrence of bidirectional gene flow may have an impact on wild populations, as new physiological races continuously emerge in weedy populations. Also, genetic variability of wild populations may favour the ability of weedy populations to overcome sunflower resistance mechanisms. PMID:25143963

  9. STRUCTURAL AND HYDROGEOLOGIC APPLICATIONS OF REMOTE SENSING DATA, EASTERN YUCATAN PENINSULA, MEXICO.

    USGS Publications Warehouse

    Southworth, C. Scott; ,

    1984-01-01

    Landsat and Seasat satellite images and aerial photographs of eastern Yucatan Peninsula, Mexico, were analyzed to delineate geologic controls of ground water. Significant interpretation results include the delineation of linear topographic swales, interpreted as fractures, extending more than 50 km along strike from the previously known limit of the Holbox fracture system; the alignment of sink holes (cenotes) and inlets (caletas) on strike with existing faults and fracture systems; and the identification of tonal anomalies in Ingles Lagoon suggesting fresh-water discharge from a submarine spring.

  10. Shear-wave velocity structure of the south-eastern part of the Iberian Peninsula from Rayleigh wave analysis

    NASA Astrophysics Data System (ADS)

    Corchete, V.; Chourak, M.

    2011-10-01

    In this study, we present the lithospheric structure of the south-eastern part of the Iberian Peninsula by means of a set of 2D images of shear velocity, for depths ranging from 0 to 50 km. This goal will be attained by means of the inversion of the Rayleigh wave dispersion. For it, the traces of 25 earthquakes occurred on the neighbouring of the study area, from 2001 to 2003, will be considered. These earthquakes have been registered by 11 broadband stations located on Iberia. All seismic events have been grouped in source zones to get an average dispersion curve for each source-station path. The dispersion curves have been measured for periods between 2 and 45 s, by combination of two digital filtering techniques: Multiple Filter Technique and Time Variable Filtering. The resulting set of source-station averaged dispersion curves has been inverted according to the generalized inversion theory, to get S-wave velocity models for each source-station path. Later, these models have been interpolated using the method of kriging, to obtain a 2D mapping of the S-wave velocity structure for the south-eastern part of Iberia. The results presented in this paper show that the techniques used here are a powerful tool to investigate the crust and upper mantle structure, through the dispersion analysis and its inversion to obtain shear velocity distributions with depth. By means of this analysis, principal structural features of the south-eastern part of Iberia, such as the existence of lateral and vertical heterogeneity in the whole study area, or the location of the Moho discontinuity at 30 km of depth (with an average S-velocity of uppermost mantle of 4.7 km/s), have been revealed. Other important structural features revealed by this analysis have been that the uppermost of Iberian massif shows higher velocity values than the uppermost of the Alpine domain, indicating that the massif is old and tectonically stable. The average velocity of the crust in Betic cordillera is of

  11. A common fungal associate of the spruce bark beetle metabolizes the stilbene defenses of Norway spruce.

    PubMed

    Hammerbacher, Almuth; Schmidt, Axel; Wadke, Namita; Wright, Louwrance P; Schneider, Bernd; Bohlmann, Joerg; Brand, Willi A; Fenning, Trevor M; Gershenzon, Jonathan; Paetz, Christian

    2013-07-01

    Norway spruce (Picea abies) forests suffer periodic fatal attacks by the bark beetle Ips typographus and its fungal associate, Ceratocystis polonica. Norway spruce protects itself against fungal and bark beetle invasion by the production of terpenoid resins, but it is unclear whether resins or other defenses are effective against the fungus. We investigated stilbenes, a group of phenolic compounds found in Norway spruce bark with a diaryl-ethene skeleton with known antifungal properties. During C. polonica infection, stilbene biosynthesis was up-regulated, as evidenced by elevated transcript levels of stilbene synthase genes. However, stilbene concentrations actually declined during infection, and this was due to fungal metabolism. C. polonica converted stilbenes to ring-opened, deglycosylated, and dimeric products. Chromatographic separation of C. polonica protein extracts confirmed that these metabolites arose from specific fungal enzyme activities. Comparison of C. polonica strains showed that rapid conversion of host phenolics is associated with higher virulence. C. polonica is so well adapted to its host's chemical defenses that it is even able to use host phenolic compounds as its sole carbon source.

  12. Restoration of the depression structure at the eastern part of central Kyushu, Japan by means of dislocation modeling

    NASA Astrophysics Data System (ADS)

    Kusumoto, Shigekazu; Takemura, Keiji; Fukuda, Yoichi; Takemoto, Shuzo

    1999-02-01

    We have attempted to restore a subsurface structure in the eastern part of central Kyushu, Japan, by combining fault motions which were modeled as dislocation planes embedded in an elastic isotropic half space. The simulated crustal deformation pattern was compared with the subsurface structures estimated from gravity anomalies and/or seismic prospecting. The modeling procedure successfully restored all tectonic basins in the area without any need for motive forces for uplift or subsidence. The results also suggest that two major tectonic events have occurred in this region. Those are (1) the formation of half-graben caused by north-south extension, and (2) the formation of the pull-apart basin caused by east-west compression.

  13. Fluoroquinolone Resistance Mechanisms and population structure of Enterobacter cloacae non-susceptible to Ertapenem in North-Eastern France

    PubMed Central

    Guillard, Thomas; Cholley, Pascal; Limelette, Anne; Hocquet, Didier; Matton, Lucie; Guyeux, Christophe; Lebreil, Anne-Laure; Bajolet, Odile; Brasme, Lucien; Madoux, Janick; Vernet-Garnier, Véronique; Barbe, Coralie; Bertrand, Xavier; de Champs on behalf of CarbaFrEst Group, Christophe

    2015-01-01

    Fluoroquinolone (FQ) agents are a potential resort to treat infection due to Enterobacteriaceae producing extended spectrum β-lactamase and susceptible to FQ. In a context of increase of non-susceptibility to carbapenems among Enterobacteriaceae, we characterized FQ resistance mechanisms in 75 Enterobacter cloacae isolates non-susceptible to ertapenem in North-Eastern France in 2012 and describe the population structure by pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Among them, 14.7% (12/75) carried a carbapenemase-encoding gene. Except one isolate producing VIM-1, the carbapenemase-producing isolates carried the well-known IncL/M pOXA48a plasmid. Most of the isolates (59/75) harbored at least a FQ-R determinant. qnr genes were predominant (40%, 30/75). The MLST study revealed that E. cloacae isolates’ clonality was wide [24 different sequence types (STs)]. The more widespread STs were ST74, ST101, ST110, ST114, and ST133. Carbapenem MICs were higher for E. cloacae ST74 than for other E. cloacae isolates. Plasmid-mediated quinolone resistance determinants were more often observed in E. cloacae ST74 isolates. These findings showed that (i) pOXA-48a is spreading in North-Eastern France, (ii) qnr is preponderant in E. cloacae, (iii) E. cloacae comprised a large amount of lineages spreading in North-Eastern France, and (iv) FQ as an alternative to β-lactams to treat ertapenem non-susceptible Enterobacteriaceae are compromised. PMID:26557115

  14. Fluoroquinolone Resistance Mechanisms and population structure of Enterobacter cloacae non-susceptible to Ertapenem in North-Eastern France.

    PubMed

    Guillard, Thomas; Cholley, Pascal; Limelette, Anne; Hocquet, Didier; Matton, Lucie; Guyeux, Christophe; Lebreil, Anne-Laure; Bajolet, Odile; Brasme, Lucien; Madoux, Janick; Vernet-Garnier, Véronique; Barbe, Coralie; Bertrand, Xavier; de Champs On Behalf Of CarbaFrEst Group, Christophe

    2015-01-01

    Fluoroquinolone (FQ) agents are a potential resort to treat infection due to Enterobacteriaceae producing extended spectrum β-lactamase and susceptible to FQ. In a context of increase of non-susceptibility to carbapenems among Enterobacteriaceae, we characterized FQ resistance mechanisms in 75 Enterobacter cloacae isolates non-susceptible to ertapenem in North-Eastern France in 2012 and describe the population structure by pulsed field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). Among them, 14.7% (12/75) carried a carbapenemase-encoding gene. Except one isolate producing VIM-1, the carbapenemase-producing isolates carried the well-known IncL/M pOXA48a plasmid. Most of the isolates (59/75) harbored at least a FQ-R determinant. qnr genes were predominant (40%, 30/75). The MLST study revealed that E. cloacae isolates' clonality was wide [24 different sequence types (STs)]. The more widespread STs were ST74, ST101, ST110, ST114, and ST133. Carbapenem MICs were higher for E. cloacae ST74 than for other E. cloacae isolates. Plasmid-mediated quinolone resistance determinants were more often observed in E. cloacae ST74 isolates. These findings showed that (i) pOXA-48a is spreading in North-Eastern France, (ii) qnr is preponderant in E. cloacae, (iii) E. cloacae comprised a large amount of lineages spreading in North-Eastern France, and (iv) FQ as an alternative to β-lactams to treat ertapenem non-susceptible Enterobacteriaceae are compromised.

  15. Factors influencing the spatial and temporal dynamics of engelmann spruce mortality during a spruce beetle outbreak on the Markagunt Plateau, Utah

    Treesearch

    R. Justin DeRose; James N. Long

    2012-01-01

    Host conditions are known to influence spruce beetle population levels, but whether they influence the spatial and temporal patterns of beetle-caused mortality during an outbreak is unknown. Using dendrochronological techniques, we quantified the spatiotemporal dynamics of a modern (late 1980s through the early 2000s) spruce beetle outbreak in Engelmann spruce on the...

  16. Diapause disruption with tebufenozide for early-instar control of the spruce budworm, Choristoneura fumiferana.

    PubMed

    Doucet, Daniel; Frisco, Caroline; Cusson, Michel; Bauce, Eric; Palli, Subba Reddy; Tomkins, Bill; Arif, Basil; Retnakaran, Arthur

    2007-08-01

    In North America, the eastern spruce budworm, Choristoneura fumiferana Clem., is an important coniferous pest against which tebufenozide has proven effective as a control product. By acting as an ecdysone agonist, tebufenozide can induce precocious moulting in late (fifth-sixth) instars but can also be carried over to the next generation owing to its persistence on foliage. The authors conducted laboratory experiments on first-instar larvae treated with tebufenozide dissolved in acetone. Larvae exposed to doses equal to or above 0.1 microg cm(-2) displayed precocious moulting in the second instar after hibernaculum spinning, which effectively disrupted diapause. Larger doses induced moulting in first instars. Evidence is provided that this dose-response difference is related to whether or not an effective dose of tebufenozide is ingested by the first instar prior to the peak of moulting hormone (20-hydroxyecdysone) in first instars. Doses ineffective to kill first instars are carried over to the second instar, where they induce a precocious moult. This type of response to tebufenozide is dependent on the presence of a moulting machinery (the EcR-USP receptor complex) that is ready for ecdysone transduction. Interestingly, ecdysone levels are low in second instars, as measured by a radioimmunoassay, which suggests that diapause in spruce budworm is maintained by a suppression of ecdysone production. Thus, diapause disruption by tebufenozide may well provide an alternative control strategy for this important pest.

  17. Relationship between the regional tectonic activity and crustal structure in the eastern Tibetan plateau discovered by gravity anomaly

    NASA Astrophysics Data System (ADS)

    Xu, Xiao; Gao, Rui; Guo, Xiaoyu

    2016-04-01

    The eastern Tibetan plateau has been getting more and more attention because it combines active faults, uplifting, and large earthquakes together in a high-population region. Based on the previous researches, the most of Cenozoic tectonic activities were related to the regional structure of the local blocks within the crustal scale. Thus, a better understanding of the crustal structure of the regional tectonic blocks is an important topic for further study. In this paper, we combined the simple Bouguer gravity anomaly with the Moho depths from previous studies to investigate the crustal structure in this area. To highlight the crustal structures, the gravity anomaly caused by the Moho relief has been reduced by forward modeling calculations. A total horizontal derivative (THD) had been applied on the gravity residuals. The results indicated that the crustal gravity residual is compatible with the topography and the geological settings of the regional blocks, including the Sichuan basin, the Chuxiong basin, the Xiaojiang fault, and the Jinhe fault, as well as the Longmenshan fault zone. The THD emphasized the west margin of Yangtze block, i.e., the Longriba fault zone and the Xiaojiang fault cut through the Yangtze block. The checkboard pattern of the gravity residual in the Songpan-Garze fold belt and Chuandian fragment shows that the crust is undergoing a southward and SE-directed extrusion, which is coincident with the flowing direction indicated from the GPS measurements. By integrating the interpretations, the stepwise extensional mechanism of the eastern Tibetan plateau is supported by the southeastward crustal deformation, and the extrusion of Chuandian fragment is achieved by Xianshuihe fault.

  18. 3D shear-wave velocity structure of the eastern Tennessee seismic zone from ambient noise correlation data

    NASA Astrophysics Data System (ADS)

    Arroucau, Pierre; Kuponiyi, Ayodeji; Vlahovic, Gordana; Powell, Chris

    2013-04-01

    The Eastern Tennessee Seismic Zone (ETSZ) is an intraplate seismic region characterized by frequent but low magnitude earthquakes and is the second most active seismic area in the United States east of the Rocky Mountains. One key question in the ETSZ is the actual relationship between earthquake distribution and geological structure at depth. Seismicity is mostly confined in the Precambrian basement, below the Paleozoic cover of the southern Appalachian foreland fold-and-thrust belt and shows little to no correlation with surface geological features. Since the middle of the seventies, the Center for Earthquake Research and Information (CERI) has installed and maintained several seismic networks in central and eastern United States. In this work, we use Rayleigh wave group and phase velocity dispersion information obtained from cross-correlation of seismic ambient noise at 24 short-period stations located in the vicinity of the ETSZ. The 3D velocity structure is estimated in four steps. First, dispersion curves are obtained for simultaneously recording station pairs for periods ranging from 2 to 20 s. Then, 2D group and phase velocity maps are determined for each period. Those maps are further used to reconstruct dispersion curves at fixed, regularly spaced locations. For each of these locations, a 1D shear-wave velocity profile is finally inverted for, that takes velocity information from previous studies into account. By providing new information about the upper crustal structure of this region, this work is a contribution to the understanding of the seismic activity of the ETSZ, and -to a broader extent- of the structure and evolution of the North American lithosphere.

  19. Middle Raceway north bank and wall view northeast between Spruce ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Middle Raceway north bank and wall view northeast between Spruce Street and Glenroe Building (upper right), gas station at top center - Great Falls/S. U. M. Power Canal System, Paterson, Passaic County, NJ

  20. 36. Photocopied August 1978. SECTION III, LOOKING SOUTHWEST FROM SPRUCE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    36. Photocopied August 1978. SECTION III, LOOKING SOUTHWEST FROM SPRUCE STREET, JUNE 13, 1902, WITH TIMBER LINING ALMOST COMPLETED. (245) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  1. Yellowheaded spruce sawfly--its ecology and management.

    Treesearch

    Steven A. Katovich; Deborah G. McCullough; Robert A. Haack

    1995-01-01

    Presents the biology and ecology of the yellowheaded spruce sawfly, and provides survey techniques and management strategies. In addition, it provides information on identification, classification, host range, and the historical records of outbreaks in the Lake States.

  2. 3. View from northeast corner, Canisteo and Spruce Streets. Photo ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. View from northeast corner, Canisteo and Spruce Streets. Photo shows the garage area (Building #5) with sawtooth roofline and front elevation of Buildings #6 and #1. - Merrill Silk Mill, 233 Canisteo Street, Hornell, Steuben County, NY

  3. 20. GROVE OF TREES PINES, MULBERRY, JUNIPER, BLUE SPRUCE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. GROVE OF TREES -- PINES, MULBERRY, JUNIPER, BLUE SPRUCE -- TRANSPLANTED FROM NEW MEXICO MANZANO MOUNTAINS, WEST OF BUILDINGS 4 AND T-59, LOOKING NORTHWEST - U. S. Veterans Administration Medical Center, 2100 Ridgecrest Southeast, Albuquerque, Bernalillo County, NM

  4. Formation of ectomycorrhizae following inoculation of containerized Sitka spruce seedlings.

    Treesearch

    C.G. Shaw; R. Molina

    1980-01-01

    Containerized Sitka spruce, [Picea sitchensis (Bong.) Carr.] were inoculated at sowing with pure cultures of either Pisolithus tinctorius (Pers.) Coker & Couch, Laccaria laccata (Scop. ex Fr.) Berk. & Br., Astraeus pteridis (Shear) Feller, Amanita pantherina...

  5. Structural characteristic and origin of intra-continental fold belt in the eastern Sichuan basin, South China Block

    NASA Astrophysics Data System (ADS)

    Li, Chuanxin; He, Dengfa; Sun, Yanpeng; He, Jinyou; Jiang, Zaixing

    2015-11-01

    The fold-and-thrust belt in the eastern Sichuan basin is represented by a series of subparallel chevron anticlines. Under the orogenic tectonic setting within the South China Block in Meso-Cenozoic period and the influence of the multi-layer detachment fault, the deformation of the thrust belt exhibits remarkably layered and large-scale intracontinental thrusting structural characteristics. In this paper, we focus on the structural geometry and deformational mechanisms using the latest two-dimensional (2D) and three-dimensional (3D) seismic reflection data in combination with well and outcrop data. The multi-layer detachment faults, especially the upper gypsum-bearing detachment in the Middle Triassic Jialingjiang Formation and lower detachment with gypsum or shale in the Lower-Middle Cambrian system, directly control the deformational styles of the study area. Interpretation of seismic sections indicates that the fold-and-thrust belt has various deformational styles during folding, including fault-propagation fold, fault-bend fold, and detachment fold with box-fold or pop-up structural geometry. Regional location and structural boundaries play significant roles in controlling the deformational styles, and distinct differences exist among the different anticlines. The Huayingshan anticline located at the front of the thrust belt shows intense structural deformation with northwestward thrusting direction and a relatively weak opposite southeastward thrusting. In addition, the anticlines exhibit structural differences along strike and the fold-and-thrust belt in the northern segment is influenced by the North China Block.

  6. Structural geometry in the eastern Pyrenees and western Gulf of Lion (Western Mediterranean)

    NASA Astrophysics Data System (ADS)

    Mauffret, Alain; Durand de Grossouvre, Bernard; Tadeu Dos Reis, Antonio; Gorini, Christian; Nercessian, Alex

    2001-11-01

    We present new seismic data from the Gulf of Lion located east of the Pyrenees on the continental shelf of the Mediterranean Sea. The deep penetration LISA (Ligurian-Sardinia Sea) seismic lines, the shots of the LISA cruise recorded on land, and the high definition ELF seismic sections allow us to present a complete picture of the tectonics in this area from the surface to the Moho level, and also to document late Miocene-early Pliocene extensional tectonics in the area. Previous studies show a prominent thinning of the crust observed from the Pyrenees towards the Gulf of Lion. The Moho depth varies from 48 km beneath the Axial Range crust (thickened during the Pyrenean Eocene Orogeny) to 21 km below the Catalan Basin in the Gulf of Lion. This crustal thinning occurred mainly during the early Miocene extension of the Mediterranean Sea. Balanced reconstructed geological sections derived from reflection and refraction seismic data allow us to evaluate the stretching factors at the crustal level. A maximum extension of 25 km is computed for the Catalan Basin area. This extension is related to detachments that penetrate the crust as deep as 11 km to the base of the brittle crust. These intra basement detachments have been confused in the past with the Paleozoic acoustic basement. The detachments show a clear listric shape and the geometry of horst and grabens can be explained by a hanging wall and footwall configuration with isostatic rebound of the footwall. The uplift in the Eastern Pyrenees (Albères and Canigou Massifs), on the other hand, is related to the late Miocene-early Pliocene extension we mapped in the area. These elevated features, probably formed by isostatic rebound, are surrounded by deep basins such as the Roussillon and El Empordà depressions. A 1.7 km uplift during the late Miocene-early Pliocene is computed in the offshore part of the Albères Massif. The cause of this Late Miocene-early Pliocene extension is not well explained although an uplift

  7. Geographical structure of endosymbiotic bacteria hosted by Bathymodiolus mussels at eastern Pacific hydrothermal vents.

    PubMed

    Ho, Phuong-Thao; Park, Eunji; Hong, Soon Gyu; Kim, Eun-Hye; Kim, Kangchon; Jang, Sook-Jin; Vrijenhoek, Robert C; Won, Yong-Jin

    2017-05-30

    Chemolithoautotrophic primary production sustains dense invertebrate communities at deep-sea hydrothermal vents and hydrocarbon seeps. Symbiotic bacteria that oxidize dissolved sulfur, methane, and hydrogen gases nourish bathymodiolin mussels that thrive in these environments worldwide. The mussel symbionts are newly acquired in each generation via infection by free-living forms. This study examined geographical subdivision of the thiotrophic endosymbionts hosted by Bathymodiolus mussels living along the eastern Pacific hydrothermal vents. High-throughput sequencing data of 16S ribosomal RNA encoding gene and fragments of six protein-coding genes of symbionts were examined in the samples collected from nine vent localities at the East Pacific Rise, Galápagos Rift, and Pacific-Antarctic Ridge. Both of the parapatric sister-species, B. thermophilus and B. antarcticus, hosted the same numerically dominant phylotype of thiotrophic Gammaproteobacteria. However, sequences from six protein-coding genes revealed highly divergent symbiont lineages living north and south of the Easter Microplate and hosted by these two Bathymodiolus mussel species. High heterogeneity of symbiont haplotypes among host individuals sampled from the same location suggested that stochasticity associated with initial infections was amplified as symbionts proliferated within the host individuals. The mussel species presently contact one another and hybridize along the Easter Microplate, but the northern and southern symbionts appear to be completely isolated. Vicariance associated with orogeny of the Easter Microplate region, 2.5-5.3 million years ago, may have initiated isolation of the symbiont and host populations. Estimates of synonymous substitution rates for the protein-coding bacterial genes examined in this study were 0.77-1.62%/nucleotide/million years. Our present study reports the most comprehensive population genetic analyses of the chemosynthetic endosymbiotic bacteria based on high

  8. Pulpability of beetle-killed spruce. Forest Service research paper

    SciTech Connect

    Scott, G.M.; Bormett, D.W.; Sutherland, N.R.; Abubakr, S.; Lowell, E.

    1996-08-01

    Infestation of the Dendroctonus rufipennis beetle has resulted in large stands of dead and dying timber on the Kenai Peninsula in Alaska. Tests were conducted to evaluate the value of beetle-killed spruce as pulpwood. The results showed that live and dead spruce wood can be pulped effectively. The two least deteriorated classes and the most deteriorated class of logs had similar characteristics when pulped; the remaining class had somewhat poorer pulpability.

  9. SPRUCE: Systems and Software Producibility Collaboration and Experimentation Environment

    DTIC Science & Technology

    2009-04-01

    SYSTEMS AND SOFTWARE PRODUCIBILITY COLLABORATION AND EXPERIMENTATION ENVIRONMENT (CONT.) Data & Analysis Center for Software (DACS) 37 2 SPRUCE users to... Analysis Center for Software (DACS) 39 4 Figure 5 shows a wiki entry from an experiment conducted for the “cache false-sharing” problem of Figure 4...The wiki allows for free-form analysis of experiment results and generation of potential ideas for future research. SPRUCE users editing the wiki

  10. Forward Modeling of Receiver Functions to Determine Crustal Structure of the Eastern Limb in TheBushveld Complex, South Africa

    NASA Astrophysics Data System (ADS)

    Loza, E.; Ramirez, C.; Nyblade, A.; Durrheim, R. J.; Raveloson, A.

    2016-12-01

    The Bushveld Igneous Complex contains the largest layered mafic intrusion on Earth, about the size of England, and has been exploited for metals such as platinum since the 1950s. Several igneous bodies within and around the complex have been dated from 2.06 Ga, possibly representing a single massive magmatic event. The Rustenburg Layered Suite of the Bushveld Igneous Complex intruded into the Transvaal sedimentary sequence, with associated volcanic rocks of the Rooiberg Group forming the roof and part of the floor. The purpose of this study is to determine whether the Rustenburg Layered Suite is a continuous bowl-shaped formation or if it is made up of two separate dipping sheets that crop out in the western and eastern limbs. If the intrusion is connected at depth, then the Moho (crust-mantle boundary) would most likely be depressed due to the weight of the 7-8km of mafic material injected into the crust. Seismic stations were installed in the eastern and northern Bushveld in 2015 to collect teleseismic data. The use of receiver functions derived from seismic data collected since 2015 has helped determine the subsurface crustal structure of the Bushveld. Receiver functions have been used to trace the contact between the high-density mafic lower zone and the low-density Transvaal sediments. The new data gathered show the Moho boundary at about 47 km, and a 5.0 Gaussian width shows a backswing consistent with a mafic-sedimentary boundary at 8km.

  11. Trophic structure and pathways of biogenic carbon flow in the eastern North Water Polynya

    NASA Astrophysics Data System (ADS)

    Tremblay, Jean-Éric; Hattori, Hiroshi; Michel, Christine; Ringuette, Marc; Mei, Zhi-Ping; Lovejoy, Connie; Fortier, Louis; Hobson, Keith A.; Amiel, David; Cochran, Kirk

    2006-10-01

    In the eastern North Water, most of the estimated annual new and net production of carbon (C) occurred during the main diatom bloom in 1998. During the bloom, at least 30% of total and new phytoplankton production occurred as dissolved organic carbon (DOC) and was unavailable for short-term assimilation into the herbivorous food web or sinking export. Based on particle interceptor traps and 234Th deficits, 27% of the particulate primary production (PP) sank out of the upper 50 m, with only 7% and 1% of PP reaching the benthos at shallow (≈200 m) and deep (≈500 m) sites, respectively. Mass balance calculations and grazing estimates agree that ≈79% of PP was ingested by pelagic consumers between April and July. During this period, the vertical flux of biogenic silica (BioSi) at 50 m was equivalent to the total BioSi produced, indicating that all of the diatom production was removed from the euphotic zone as intact cells (direct sinking) or empty frustules (grazing or lysis). The estimated flux of empty frustules was consistent with rates of herbivory by the large, dominant copepods and appendicularians during incubations. Since the carbon demand of the dominant planktivorous bird, Alle alle, amounted to ≈2% of the biomass synthesized by its main prey, the large copepod Calanus hyperboreus, most of the secondary carbon production was available to pelagic carnivores. Stable isotopes indicated that the biomass of predatory amphipods, polar cod and marine mammals was derived from these herbivores, but corresponding carbon fluxes were not quantified. Our analysis shows that a large fraction of PP in the eastern North Water was ingested by consumers in the upper 50 m, leading to substantial carbon respiration and DOC accumulation in surface waters. An increasingly early and prolonged opening of the Artic Ocean is likely to promote the productivity of the herbivorous food web, but not the short-term efficiency of the particulate, biological CO 2 pump.

  12. Blue whale population structure along the eastern South Pacific Ocean: evidence of more than one population.

    PubMed

    Torres-Florez, J P; Hucke-Gaete, R; LeDuc, R; Lang, A; Taylor, B; Pimper, L E; Bedriñana-Romano, L; Rosenbaum, H C; Figueroa, C C

    2014-12-01

    Blue whales (Balaenoptera musculus) were among the most intensively exploited species of whales in the world. As a consequence of this intense exploitation, blue whale sightings off the coast of Chile were uncommon by the end of the 20th century. In 2004, a feeding and nursing ground was reported in southern Chile (SCh). With the aim to investigate the genetic identity and relationship of these Chilean blue whales to those in other Southern Hemisphere areas, 60 biopsy samples were collected from blue whales in SCh between 2003 and 2009. These samples were genotyped at seven microsatellite loci and the mitochondrial control region was sequenced, allowing us to identify 52 individuals. To investigate the genetic identity of this suspected remnant population, we compared these 52 individuals to blue whales from Antarctica (ANT, n = 96), Northern Chile (NCh, n = 19) and the eastern tropical Pacific (ETP, n = 31). No significant differentiation in haplotype frequencies (mtDNA) or among genotypes (nDNA) was found between SCh, NCh and ETP, while significant differences were found between those three areas and Antarctica for both the mitochondrial and microsatellite analyses. Our results suggest at least two breeding population units or subspecies exist, which is also supported by other lines of evidence such as morphometrics and acoustics. The lack of differences detected between SCh/NCh/ETP areas supports the hypothesis that eastern South Pacific blue whales are using the ETP area as a possible breeding area. Considering the small population sizes previously reported for the SCh area, additional conservation measures and monitoring of this population should be developed and prioritized.

  13. Negative impacts of high temperatures on growth of black spruce forests intensify with the anticipated climate warming.

    PubMed

    Girardin, Martin P; Hogg, Edward H; Bernier, Pierre Y; Kurz, Werner A; Guo, Xiao Jing; Cyr, Guillaume

    2016-02-01

    An increasing number of studies conclude that water limitations and heat stress may hinder the capacity of black spruce (Picea mariana (Mill.) B.S.P.) trees, a dominant species of Canada's boreal forests, to grow and assimilate atmospheric carbon. However, there is currently no scientific consensus on the future of these forests over the next century in the context of widespread climate warming. The large spatial extent of black spruce forests across the Canadian boreal forest and associated variability in climate, demography, and site conditions pose challenges for projecting future climate change responses. Here we provide an evaluation of the impacts of climate warming and drying, as well as increasing [CO2 ], on the aboveground productivity of black spruce forests across Canada south of 60°N for the period 1971 to 2100. We use a new extensive network of tree-ring data obtained from Canada's National Forest Inventory, spatially explicit simulations of net primary productivity (NPP) and its drivers, and multivariate statistical modeling. We found that soil water availability is a significant driver of black spruce interannual variability in productivity across broad areas of the western to eastern Canadian boreal forest. Interannual variability in productivity was also found to be driven by autotrophic respiration in the warmest regions. In most regions, the impacts of soil water availability and respiration on interannual variability in productivity occurred during the phase of carbohydrate accumulation the year preceding tree-ring formation. Results from projections suggest an increase in the importance of soil water availability and respiration as limiting factors on NPP over the next century due to warming, but this response may vary to the extent that other factors such as carbon dioxide fertilization, and respiration acclimation to high temperature, contribute to dampening these limitations.

  14. Negative impacts of high temperatures on growth of black spruce forests intensify with the anticipated climate warming

    NASA Astrophysics Data System (ADS)

    Girardin, M. P.; Hogg, T.; Kurz, W.; Bernier, P. Y.; Guo, X. J.; Cyr, G.

    2015-12-01

    An increasing number of studies conclude that water limitations and heat stress may hinder the capacity of black spruce (Picea mariana (Mill.) B.S.P.) trees, a dominant species of Canada's boreal forests, to grow and assimilate atmospheric carbon. However, there is currently no scientific consensus on the future of these forests over the next century in the context of widespread climate warming. The large spatial extent of black spruce forests across the Canadian boreal forest and associated variability in climate, demography and site conditions pose challenges for projecting future climate change responses. Here we provide an evaluation of the impacts of climate warming and drying, as well as increasing [CO2], on the aboveground productivity of black spruce forests across Canada south of 60ºN for the period 1971 to 2100. We use a new extensive network of tree-ring data obtained from Canada's National Forest Inventory, spatially-explicit simulations of Net Primary Productivity (NPP) and its drivers, and multivariate statistical modelling. We found that soil water availability is a significant driver of black spruce inter-annual variability in productivity across broad areas of the western to eastern Canadian boreal forest. Inter-annual variability in productivity was also found to be driven by autotrophic respiration in the warmest regions. In most regions, the impacts of soil water availability and respiration on inter-annual variability in productivity occurred during the phase of carbohydrate accumulation the year preceding tree ring formation. Results from projections suggest an increase in the importance of soil water availability and respiration as limiting factors on NPP over the next century due to warming, but this response may vary to the extent that other factors such as carbon dioxide fertilization, and respiration acclimation to high temperature, contribute to dampening these limitations.

  15. Canopy-Forming Seaweeds in Urchin-Dominated Systems in Eastern Canada: Structuring Forces or Simple Prey for Keystone Grazers?

    PubMed Central

    Blain, Caitlin; Gagnon, Patrick

    2014-01-01

    Models of benthic community dynamics for the extensively studied, shallow rocky ecosystems in eastern Canada emphasize kelp-urchin interactions. These models may bias the perception of factors and processes that structure communities, for they largely overlook the possible contribution of other seaweeds to ecosystem resilience. We examined the persistence of the annual, acidic (H2SO4), brown seaweed Desmarestia viridis in urchin barrens at two sites in Newfoundland (Canada) throughout an entire growth season (February to October). We also compared changes in epifaunal assemblages in D. viridis and other conspicuous canopy-forming seaweeds, the non-acidic conspecific Desmarestia aculeata and kelp Agarum clathratum. We show that D. viridis can form large canopies within the 2-to-8 m depth range that represent a transient community state termed “Desmarestia bed”. The annual resurgence of Desmarestia beds and continuous occurrence of D. aculeata and A. clathratum, create biological structure for major recruitment pulses in invertebrate and fish assemblages (e.g. from quasi-absent gastropods to >150 000 recruits kg−1 D. viridis). Many of these pulses phase with temperature-driven mass release of acid to the environment and die-off in D. viridis. We demonstrate experimentally that the chemical makeup of D. viridis and A. clathratum helps retard urchin grazing compared to D. aculeata and the highly consumed kelp Alaria esculenta. In light of our findings and related studies, we propose fundamental changes to the study of community shifts in shallow, rocky ecosystems in eastern Canada. In particular, we advocate the need to regard certain canopy-forming seaweeds as structuring forces interfering with top-down processes, rather than simple prey for keystone grazers. We also propose a novel, empirical model of ecological interactions for D. viridis. Overall, our study underscores the importance of studying organisms together with cross-scale environmental variability

  16. Nonlinearity Modulating Central Pacific- and Eastern Pacific-El Niño Events in Intensities and Spatial Structures

    NASA Astrophysics Data System (ADS)

    Duan, Wansuo; Huang, Chaoming; Xu, Hui

    2017-04-01

    The influence of nonlinearity on the intensities and spatial structures of central Pacific (CP-) El Niño and eastern Pacific (EP-) El Niño is comparatively investigated in the intermediate-complexity Zebiak-Cane model. The nonlinear component of the perturbed temperature advection (NTA), as the source of nonlinearities in the Zebiak-Cane model, shows warming rate in the central equatorial Pacific for CP-El Niño events and makes less contributions to the CP-El Niño structure selection; but it presents warming rate in the eastern equatorial Pacific for EP-El Niño event and significantly promotes EP-El Niño events in El Niño-type selection. The NTA associated with CP- and EP-El Niño events also shows to be different in amplitudes and the former is smaller than the latter, which causes that CP-El Niño are weakly modulated by small NTA in intensities and may be controlled by weak nonlinearity while EP-El Niño are significantly enhanced by large NTA in amplitudes and likely to be modulated by relative strong nonlinearity. Then the CP-El Niño is often weaker than the EP-El Niño. In terms of the NTA associated with CP- and EP-El Niño having different characteristics in spatial structures and intensities and its role in selecting El Niño modes, it can be thought of as that the diversity of El Niño events may be closely related to the change of nonlinear characteristics in the tropical Pacific.

  17. Structure, Aboveground Biomass, and Soil Characterization of Avicennia marina in Eastern Mangrove Lagoon National Park, Abu Dhabi

    NASA Astrophysics Data System (ADS)

    Alsumaiti, Tareefa Saad Sultan

    Mangrove forests are national treasures of the United Arab Emirates (UAE) and other arid countries with limited forested areas. Mangroves form a crucial part of the coastal ecosystem and provide numerous benefits to society, economy, and especially the environment. Mangrove trees, specifically Avicennia marina, are studied in their native habitat in order to characterize their population structure, aboveground biomass, and soil properties. This study focused on Eastern Mangrove Lagoon National Park in Abu Dhabi, which was the first mangrove protected area to be designated in UAE. In situ measurements were collected to estimate Avicennia marina status, mortality rate (%), height (m), crown spread (m), stem number, diameter at breast height (cm), basal area (m), and aboveground biomass (t ha-1 ). Small-footprint aerial light detection and ranging (LIDAR) data acquired by UAE were processed to characterize mangrove canopy height and aboveground biomass density. This included extraction of LIDAR-derived height percentile statistics, segmentation of the forest into structurally homogenous units, and development of regression relationships between in situ reference and remote sensing data using a machine learning approach. An in situ soil survey was conducted to examine the soils' physical and chemical properties, fertility status, and organic matter. The data of soil survey were used to create soil maps to evaluate key characteristics of soils, and their influence on Avicennia marina in Eastern Mangrove Lagoon National Park. The results of this study provide new insights into Avicennia marina canopy population, structure, aboveground biomass, and soil properties in Abu Dhabi, as data in such arid environments is lacking. This valuable information can help in managing and preserving this unique ecosystem.

  18. Monoterpene emissions from bark beetle infested Engelmann spruce trees

    NASA Astrophysics Data System (ADS)

    Amin, Hardik S.; Russo, Rachel S.; Sive, Barkley; Richard Hoebeke, E.; Dodson, Craig; McCubbin, Ian B.; Gannet Hallar, A.; Huff Hartz, Kara E.

    2013-06-01

    Bark beetle infestation impacts the health of coniferous forests, which are an important source of volatile organic compounds (VOCs) to the atmosphere. The types and amounts of VOCs emitted from forests can influence secondary organic aerosol (SOA) formation and impact overall air quality. In this initial work, the impact of bark beetle infestation on SOA precursors from Engelmann spruce is assessed. The VOCs emitted from the trunk of infested and healthy spruce trees were sampled using both sorbent traps and evacuated canisters that were analyzed by gas chromatography/mass spectroscopy. The samples from the infested spruce tree suggest a nine-fold enhancement in the total VOC emissions. The dominant VOCs in the infested spruce trees were 3-carene, β-pinene, and α-pinene. The increase observed in VOCs sampled at the trunk of the infested spruce was consistent with increases observed at infested lodgepole pine trunks. However, the types and amounts of VOCs emitted from Engelmann spruce and lodgepole pine are different, which suggests that additional measures of VOC emissions are needed to characterize the impact of bark beetle infestation on VOC emissions and SOA precursors.

  19. Labeling Feral Spruce Budworm (Lepidoptera: Tortricidae) Populations With Rubidium.

    PubMed

    MacKinnon, Wayne; Eveleigh, Eldon; Silk, Peter; Forbes, Glen

    2016-04-01

    Rubidium (Rb) is a trace element that occurs naturally in low concentrations and is easily absorbed by plants, making it a useful tool for labeling insect defoliators, such as spruce budworm (Choristoneura fumiferana Clemens). Balsam fir trees (Abies balsamea (L.) Miller) injected with either 8 or 16 g per tree of rubidium chloride (RbCl) showed quick uptake and distribution throughout the crown, with no negative effects on tree shoot growth or spruce budworm survival and development. Adult spruce budworm that fed as larvae on trees injected with RbCl were clearly labeled, with significantly higher Rb concentrations than the background levels found in adults that fed as larvae on control trees. Rb concentrations in feral spruce budworm adults for both the 8 g (9 µg/g) and 16 g (25 µg/g) per tree treatments were at least five times lower than those in laboratory-reared adults on 1,000 µg/g RbCl diet (125 µg/g); survival, development, pupal weight, sex ratio, and mating status of spruce budworm were not adversely affected by Rb treatment. Egg masses laid by feral females that fed as larvae on Rb-labeled trees were also labeled with Rb. Injecting trees with RbCl is a viable technique for labeling feral spruce budworm populations to help distinguish local populations from immigrants to better evaluate the success of early intervention strategies such as mating disruption. © Crown copyright 2016.

  20. Public health research support through the European structural funds in central and eastern Europe and the Mediterranean.

    PubMed

    McCarthy, Mark

    2012-04-05

    Public health research provides evidence for practice across fields including health care, health promotion and health surveillance. Levels of public health research vary markedly across European Union (EU) countries, and are lowest in the EU's new member states (in Central and Eastern Europe and the Mediterranean). However, these countries now receive most of the EU's Structural Funds, some of which are allocated to research. STEPS, an EU-funded study, sought to assess support for public health research at national and European levels. To identify support through the Structural funds, STEPS drew information from country respondents and internet searches for all twelve EU new member states. The EU allocates annually around €7 billion through the Structural Funds for member states' own use on research. These funds can cover infrastructure, academic employment, and direct research grants. The programmes emphasise links to business. Support for health research includes major projects in biosciences, but direct support for public health research was found in only three countries - Cyprus, Latvia and Lithuania. Public health research is not prioritised in the EU's Structural Funds programme in comparison with biomedicine. For the research dimension of the new European programme for Structural Funds 2014-2002, ministries of health should propose public health research to strengthen the evidence-base for European public health policy and practice.

  1. Characteristics of Shear Wave Velocity Structures Beneath the Gulf of St. Lawrence, Eastern Canada from Ambient Seismic Noise Tomography

    NASA Astrophysics Data System (ADS)

    Kuponiyi, A.; Kao, H.; Cassidy, J. F.; Dosso, S. E.; Spence, G.

    2016-12-01

    Continuous ambient seismic noise waveforms collected from 2005-2008 at 24 broadband stations located in and around the Gulf St. Lawrence (GSL) are processed to derive Rayleigh wave dispersion curves. We conduct both surface wave tomography inversion and trans-dimensional Bayesian inversion to characterize the 3-D shear wave velocity (Vs) structure beneath the GSL up to 20 km depth. Our results indicate that the entire GSL region can be divided into three broad sections. In the northern GSL, the Grenville Province (i.e., the Proterozoic edge) is dominated by high Vs. However, scattered low Vs structures can be found to correspond to well-known anorthorsite sites. In contrast, the central section corresponds to a weak belt with generally low Vs. The southernmost section of the GSL is characterized by high Vs structures belonging to the Meguma and Avalon terranes. The basement structure at the eastern segment of the Appalachian Structural Front is characterized by relatively low-Vs. Prominent low Vs are found to coincide with locations of most graben structures and sedimentary basins in the GSL. Both the depth of the sedimentary basement and the geometry of major sedimentary basins are well imaged with the thickest sedimentary layer (over 15 km) found near the western edge of the Magdalen basin. At both shallow and mid-crust depths, prominent high Vs are found near the boundaries of the Ordovician-Silurian Anticosti and the Carboniferous Magdalen Basins. The deepest prominent low Vs structures correspond to displaced/deformed Humber zone sediments buried deep beneath Dunnage zone of Newfoundland. High Vs structures with variable thicknesses are found to overlie parts of the Canadian Maritime Basins. These top high Vs structures are generally very thin (<3 km) and can be explained as the manifestation of top volcanic layers in the region.

  2. Climate-growth relationships for bog-grown black spruce in northern Minnesota

    SciTech Connect

    Vogel, K.J. )

    1993-06-01

    Black spruce (Picea mariana) tree-ring chronologies were derived for three bogs in northern Minnesota. Standard chronologies were highly intercorrelated (0.72 to 0.87). The ring-width variability attributable to a common signal ranged from 38.6 to 56.8 percent which is large for closed canopy eastern forests. These chronologies exhibited great serial correlation, therefore all chronologies were autoregressively modelled prior to climatic analyses. Each chronology was compared to monthly temperature and precipitation data from a nearby weather station. Strengths of linear relationships were measured by the product-moment correlation coefficient. May and August temperatures from the previous year and March precipitation of the current year were significantly correlated with ring-width indices. These data suggest that tree-ring chronologies from mid-continental peatlands may be a valuable, though presently ignored, source of paleoclimatic data.

  3. Vertical and horizontal transport of energy and matter by coherent motions in a tall spruce canopy

    NASA Astrophysics Data System (ADS)

    Serafimovich, A.; Siebicke, L.; Foken, T.

    2009-04-01

    In a forested ecosystem low frequency coherent events contribute significantly to the budgets of momentum, heat and matter. In the frame of EGER (ExchanGE processes in mountainous Regions) project the contribution of coherent structures to the vertical and horizontal transfer of energy and matter in a tall spruce canopy was investigated. Two measuring campaigns were carried out in North-Eastern Bavaria at the Waldstein site in the Fichtelgebirge mountains. Observations of coherent structures were obtained by a vertical profile of sonic anemometers equipped with fast CO2 and H2O analyzers covering all parts of the forest up to the lower part of the roughness sub layer. In addition five small masts were set up in the trunk space of the forest and equipped with sonic anemometers, humidity and temperature sensors as well as CO2 analyzers. Combination of measurements done in vertical and horizontal directions allows us to investigate coherent structures, their temporal scales, their role in flux transport and vertical coupling between the subcanopy, canopy and air above the canopy level. To extract coherent structures from the turbulent time series, the technique based on the wavelet transform has been used. Conditional sampling analysis showed a domination of coherent structure signatures in vertical wind measurements with probable temporal scales in the order of 10 s to 30 s. The mean temporal scale of coherent structures detected in the trunk space of the forest was 30 - 40 s. The number of coherent structures detected at the slim and tall tower was found to be 40% less than the number of coherent structures detected at the heavy main tower. In contrast to the slim tower the main tower is more massive and was equipped with more instruments resulting for additional generation of turbulence. The Reynolds-averaged flux and flux contribution of coherent structures were derived using a triple decomposition for the detected and conditionally averaged time series, when

  4. Soil-solution chemistry in a low-elevation spruce-fir ecosystem, Howland, Maine

    USGS Publications Warehouse

    Fernandez, Ivan J.; Lawrence, Gregory B.; Son, Yowhan

    1995-01-01

    Soil solutions were collected monthly by tension and zero-tension lysimeters in a low-elevation red spruce stand in east-central Maine from May 1987 through December 1992. Soil solutions collected by Oa tension lysimeters had higher concentrations of most constituents than the Oa zero-tension lysimeters. In Oa horizon soil solutions growing season concentrations for SO4, Ca, and Mg averaged 57, 43, and 30 μmol L−1 in tension lysimeters, and 43, 28, and 19 μmol L−1 in zero-tension lysimeters, respectively. Because tension lysimeters remove water held by the soil at tensions up to 10 kPa, solutions are assumed to have more time to react with the soil compared to freely draining solutions collected by zero-tension lysimeters. Solutions collected in the Bs horizon by both types of collectors were similar which was attributed to the frequency of time periods when the water table was above the Bs lysimeters. Concentrations of SO4 and NO3 at this site were lower than concentrations reported for most other eastern U.S. spruce-fir sites, but base cation concentrations fell in the same range. Aluminum concentrations in this study were also lower than reported for other sites in the eastern U.S. and Ca/Al ratios did not suggest inhibition of Ca uptake by roots. Concentrations of SO4, Ca, K, and Cl decreased significantly in both the Oa and Bs horizons over the 56-month sampling period, which could reflect decreasing deposition rates for sulfur and base cations, climatic influences, or natural variation. A longer record of measured fluxes will be needed to adequately define temporal trends in solution chemistry and their causes.

  5. Population structure of guppies in north-eastern Venezuela, the area of putative incipient speciation

    PubMed Central

    2014-01-01

    Background Geographic barriers to gene flow and divergence among populations in sexual traits are two important causes of genetic isolation which may lead to speciation. Genetic isolation may be facilitated if these two mechanisms act synergistically. The guppy from the Cumaná region (within the Cariaco drainage) of eastern Venezuela has been previously described as a case of incipient speciation driven by sexual selection, significantly differentiated in sexual colouration and body shape from the common guppy, Poecilia reticulata. The latter occurs widely in northern Venezuela, including the south-eastern side of Cordillera de la Costa, where it inhabits streams belonging to the San Juan drainage. Here, we present molecular and morphological analyses of differentiation among guppy populations in the Cariaco and San Juan drainages. Our analyses are based on a 953 bp long mtDNA fragment, a set of 15 microsatellites (519 fish from 20 populations), and four phenotypic traits. Results Both microsatellite and mtDNA data showed that guppies inhabiting the two drainages are characterised by a significant genetic differentiation, but a higher proportion of the genetic variance was distributed among populations within regions. Most guppies in the Cariaco drainage had mtDNA from a distinct lineage, but we also found evidence for widespread introgression of mtDNA from the San Juan drainage into the Cariaco drainage. Phenotypically, populations in the two regions differed significantly only in the number of black crescents. Phenotypic clustering did not support existence of two distinct groupings, but indicated a degree of distinctiveness of Central Cumaná (CC) population. However, CC population showed little differentiation at the neutral markers from the proximate populations within the Cariaco drainage. Conclusions Our findings are consistent with only partial genetic isolation between the two geographic regions and indicate that the geographic barrier of Cordillera de

  6. Influence of structural setting on sulphur isotopes in Archean orogenic gold deposits, Eastern Goldfields Province, Yilgarn, Western Australia

    NASA Astrophysics Data System (ADS)

    Hodkiewicz, P. F.; Groves, D. I.; Davidson, G. J.; Weinberg, R. F.; Hagemann, S. G.

    2009-02-01

    The published mean δ34S values of ore-related pyrites from orogenic gold deposits of the Eastern Goldfields Province, Yilgarn Craton lie between -4‰ and +4‰. As for orogenic gold deposits worldwide, most deposits have positive means and a restricted range of δ34S values, but some have negative means and wider ranges of δ34S values. Wall-rock carbonation and back-mixing of similar-source fluids with different fluid pathways can explain some of the more negative δ34S signatures. However, structural setting appears to be the most important factor controlling ore-fluid oxidation state and hence the distribution of δ34S values in gold-related pyrites. Shear-hosted deposits appear to have experienced fluid-dominated processes such as phase separation, whereas stockwork, vein-hosted or disseminated deposits formed under conditions of greater rock buffering. At Victory-Defiance, in particular, negative δ34S values are more common in gently dipping dilational structures, compared to more compressional steeply dipping structures. It appears most likely that fluid-pressure fluctuations during fault-valve cycles establish different fluid-flow regimes in structures with different orientations. Rapid fluid-pressure fluctuations in dilational structures during seismic activity can cause partitioning of reduced gas phases from the ore fluid during extreme phase separation and hence are an effective method of ore-fluid oxidation, leading to large, local fluctuations in oxidation state. It is thus not necessary to invoke mixing with oxidised magmatic fluids to explain δ34S signatures indicative of oxidation. In any case, available, robust geochronology in the Eastern Goldfields Province does not support the direct involvement of oxidised magmatic fluids from adjacent granitic intrusions in orogenic gold genesis. Thus, negative mean δ34S values and large variations in δ34S values of ore-related pyrites in world-class orogenic gold deposits are interpreted to result from

  7. Stand structure and composition provide differential tree-ring growth signals in eastern U.S. forests

    NASA Astrophysics Data System (ADS)

    Alexander, M. R.; Rollinson, C.; Dye, A.; Pederson, N.; Moore, D. J.; Trouet, V.

    2016-12-01

    The assumption that a single dominant climatic factor synchronizes regional forest growth response is the foundation of annually resolved climate reconstructions. However, growth-limiting factors affect individual trees and in complex forests, such as those in the eastern U.S., these limitations may not be uniform across the entire stand. Forest structure and composition can influence climate growth responses and result in multiple growth signals recorded in the tree rings that may not be isolated using conventional techniques. To address this issue, we collected tree cores from five eastern U.S. forest stands that are influenced by large-scale climate factors as well as small-scale ecological pressures, such as competition between individuals. We used generalized additive mixed models to form multivariate models of tree growth at the site-, species-, and canopy class-levels that account for the simultaneous influences that climate and size factors exert on growth through time. Species- and canopy position-specific models adhere more closely to observations (R2 = 0.73 and R2 = 0.71, respectively) than the site-level model (R2 = 0.60). Across all models, sensitivities to temperature and size are more dynamic through time than precipitation sensitivity. Size is the primary limiting factor as trees establish during the juvenile phase and temperature and precipitation limit growth as stands mature and individuals emerge into the canopy. We see that the species response to climate is relatively well conserved across all sites, but the dynamic nature of the size effect unique to each site alters the expressed limiting factor. We find that sub-canopy individuals show an opposite response to temperature than that the dominant and intermediate strata, likely due to the microclimate conditions created by a stratified canopy. Tree growth is thus limited by a combination of climatological and forest structural factors (i.e. canopy class) and growth limitations vary through

  8. Mother–offspring distances reflect sex differences in fine-scale genetic structure of eastern grey kangaroos

    PubMed Central

    King, Wendy J; Garant, Dany; Festa-Bianchet, Marco

    2015-01-01

    Natal dispersal affects life history and population biology and causes gene flow. In mammals, dispersal is usually male-biased so that females tend to be philopatric and surrounded by matrilineal kin, which may lead to preferential associations among female kin. Here we combine genetic analyses and behavioral observations to investigate spatial genetic structure and sex-biased dispersal patterns in a high-density population of mammals showing fission–fusion group dynamics. We studied eastern grey kangaroos (Macropus giganteus) over 2 years at Wilsons Promontory National Park, Australia, and found weak fine-scale genetic structure among adult females in both years but no structure among adult males. Immature male kangaroos moved away from their mothers at 18–25 months of age, while immature females remained near their mothers until older. A higher proportion of male (34%) than female (6%) subadults and young adults were observed to disperse, although median distances of detected dispersals were similar for both sexes. Adult females had overlapping ranges that were far wider than the maximum extent of spatial genetic structure found. Female kangaroos, although weakly philopatric, mostly encounter nonrelatives in fission–fusion groups at high density, and therefore kinship is unlikely to strongly affect sociality. PMID:26045958

  9. Species diversity of remnant calcareous grasslands in south eastern Germany depends on litter cover and landscape structure

    NASA Astrophysics Data System (ADS)

    Huber, Stephanie; Huber, Birgit; Stahl, Silvia; Schmid, Christoph; Reisch, Christoph

    2017-08-01

    Species diversity depends on, often interfering, multiple ecological drivers. Comprehensive approaches are hence needed to understand the mechanisms determining species diversity. In this study, we analysed the impact of vegetation structure, soil properties and fragmentation on the plant species diversity of remnant calcareous grasslands, therefore, in a comparative approach. We determined plant species diversity of 18 calcareous grasslands in south eastern Germany including all species and grassland specialists separately. Furthermore, we analysed the spatial structure of the grasslands as a result of fragmentation during the last 150 years (habitat area, distance to the nearest calcareous grassland and connectivity in 1830 and 2013). We also collected data concerning the vegetation structure (height of the vegetation, cover of bare soil, grass and litter) and the soil properties (content of phosphorous and potassium, ratio of carbon and nitrogen) of the grassland patches. Data were analysed using Bayesian multiple regressions. We observed a habitat loss of nearly 80% and increasing isolation between grasslands since 1830. In the Bayesian multiple regressions the species diversity of the studied grasslands depended negatively on cover of litter and to a lower degree on the distance to the nearest calcareous grassland in 2013, whereas soil properties had no significant impact. Our study supports the observation that vegetation structure, which strongly depends on land use, is often more important for the species richness of calcareous grasslands than fragmentation or soil properties. Even small and isolated grasslands may, therefore, contribute significantly to the conservation of species diversity, when they are still grazed.

  10. Peaceful Nuclear Explosion Seismogram Analysis: Constraining the Velocity Structure of Eastern Siberia

    NASA Astrophysics Data System (ADS)

    Burkhard, K. M.; Eriksen, Z. T.; Mackey, K. G.

    2016-12-01

    Peaceful Nuclear Explosions (PNEs), detonated by the former Soviet Union, are seismologically significant because they are so-called Ground Truth events, where the depth and geographic coordinates of energy release (detonation) are precisely known. Seismograms from about 20 regional stations for seven PNEs in eastern Siberia (Neva-1, Neva 2-1 and Neva 2-2 in Yakutia, and Rift-3, Batholith-1, Meteorite-5 and Kraton-3 in the Baikal region) were digitized from analog records, allowing modern processing techniques to be applied to the waveforms. Pn (P1 & P2), P*, Pg, Sn, Sg, and eU (unknown) phases were identified to investigate seismic velocities. Regional average velocities, dominated by paths within the Siberian Craton, are: Pn = 8.28 km/s, P* = 7.32 km/s, Pg = 6.20 km/s, Sn = 4.67 km/s, and Sg = 3.55 km/s. Travel paths located within the Siberian Craton are consistent with fast Pn and Sn travel-time residuals observed near the Laptev Sea. Additional PNE seismograms are being digitized to further differentiate path effects and to understand regional phase identification and velocities.

  11. Eastern Aphrodite Terra on Venus - Characteristics, structure, and mode of origin

    NASA Technical Reports Server (NTRS)

    Crumpler, L. S.

    1990-01-01

    Altimetric and radar-image cross-strike discontinuities (CSDs) are found to cut across the nearly east-west strike of Eastern Aphrodite (EA) Terra, dividing or segmenting it into offset domains. Each of these domains is characterized by a discontinuous central chasma or trough. These features have been mapped in the altimetric and radar image data of EA on the basis of abrupt termination of riftlike central chasma, offset, and segmentation of the center highlands, and radar image discontinuities previously mapped in Western Aphrodite in terms of length, orientation, and influence on the central highlands and adjacent lowlands. It is concluded that EA displays a variety of geological and geophysical characteristics similar to those occuring at divergent boundaries. The surface map characteristics are the result of a great horizontal motion of the crust diverging from a well-defined linear region, a process that can occur whether the surface is part of a thick and strong plate detached from mantle convection or part of a thin and weak layer attached to a deep convective limb.

  12. Maps Showing Geology and Shallow Structure of Eastern Rhode Island Sound and Vineyard Sound, Massachusetts

    USGS Publications Warehouse

    O'Hara, Charles J.; Oldale, Robert N.

    1980-01-01

    This report presents results of marine studies conducted by the U.S. Geological Survey (USGS) during the summers of 1975 and 1976 in eastern Rhode Island Sound and Vineyard Sound (fig. 1) located off the southeastern coast of Massachusetts. The study was made in cooperation with the Massachusetts Department of Public Works and the New England Division of the U.S. Army Corps of Engineers. It covered an area of the Atlantic Inner Continental Shelf between latitude 41 deg 12' and 41 deg 33'N, and between longitude 70 deg 37' and 71 deg 15'W (see index map). Major objectives included assessment of sand and gravel resources, environmental impact evaluation both of offshore mining of these resources and of offshore disposal of solid waste and dredge spoil material, identification and mapping of the offshore geology, and determination of the geologic history of this part of the Inner Shelf. A total of 670 kilometers (km) of closely spaced high-resolution seismic-reflection profiles, 224 km of side-scan sonar data, and 16 cores totaling 90 meters (m) of recovered sediment, were collected during the investigation. This report is companion to geologic maps published for Cape Cod Bay (Oldale and O'Hara, 1975) and Buzzards Bay, Mass. (Robb and Oldale, 1977).

  13. Pre-rift basement structure and syn-rift faulting at the eastern onshore Gulf of Corinth Rift

    NASA Astrophysics Data System (ADS)

    Kranis, Haralambos; Skourtsos, Emmanuel; Gawthorpe, Robert; Leeder, Mike; Stamatakis, Michael

    2015-04-01

    %B We present results of recent field-based research with a view to providing information about and constraints on the initiation and evolution of the Gulf of Corinth (GoC) Rift. The onshore geology and structure of the GoC rift has been studied intensively and extensively; however most research efforts have focused on the western and partly the central parts. The last few years, efforts are being made to extend the scope of research in less-studied areas, such as the eastern southern onshore part of the GoC rift, trying to address two major issues in rift initiation and evolution, namely syn-rift faulting and pre-rift basement structure. While fault spacing and length appears to be well-constrained for the western and central parts of the GoC Rift, further east -and especially in the uplifted onshore southern part- this is thought to increase dramatically, as there are practically no mapped faults. We argue, however, that this may be a false image, owing to (i) the difficulty in identifying fault structures within a thick, fairly monotonous syn-rift sequence; (ii) the lesser attention this part has drawn; and (ii) the fact that the published summary geological and tectonic maps of the GoC area are based on the dated geological maps that cover the eastern and northern onshore shoulders of the Rift. Moreover, new field data provide new information on pre-rift structure: while only the topmost thrust sheet of the Hellenide nappe stack (Pindos Unit) was thought to crop out at the eastern southern onshore part, we mapped the underlying, non-metamorphic carbonate Unit (Tripolis Unit), which crops out within the footwall of a key intra-basin block (Xylokastro block). A minor outcrop further east, may also belong to this Unit, providing basement control, in connection with recently published offshore fault data. The mapping of these outcrops, combined with a revised stratigraphical framework for the early syn-rift deposits, allows the identification and mapping of faults

  14. Near Real-time Ecological Forecasting of Peatland Responses to Warming and CO2 Treatment through EcoPAD-SPRUCE

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Jiang, J.; Stacy, M.; Ricciuto, D. M.; Hanson, P. J.; Sundi, N.; Luo, Y.

    2016-12-01

    Ecological forecasting is critical in various aspects of our coupled human-nature systems, such as disaster risk reduction, natural resource management and climate change mitigation. Novel advancements are in urgent need to deepen our understandings of ecosystem dynamics, boost the predictive capacity of ecology, and provide timely and effective information for decision-makers in a rapidly changing world. Our Ecological Platform for Assimilation of Data (EcoPAD) facilitates the integration of current best knowledge from models, manipulative experimentations, observations and other modern techniques and provides both near real-time and long-term forecasting of ecosystem dynamics. As a case study, the web-based EcoPAD platform synchronizes real- or near real-time field measurements from the Spruce and Peatland Responses Under Climatic and Environmental Change Experiment (SPRUCE), a whole ecosystem warming and CO2 enrichment treatment experiment, assimilates multiple data streams into process based models, enhances timely feedback between modelers and experimenters, and ultimately improves ecosystem forecasting and makes best utilization of current knowledge. In addition to enable users to (i) estimate model parameters or state variables, (ii) quantify uncertainty of estimated parameters and projected states of ecosystems, (iii) evaluate model structures, (iv) assess sampling strategies, and (v) conduct ecological forecasting, EcoPAD-SPRUCE automated the workflow from real-time data acquisition, model simulation to result visualization. EcoPAD-SPRUCE promotes seamless feedback between modelers and experimenters, hand in hand to make better forecasting of future changes. The framework of EcoPAD-SPRUCE (with flexible API, Application Programming Interface) is easily portable and will benefit scientific communities, policy makers as well as the general public.

  15. Host preference of the brown spruce longhorned beetle, Tetropium fuscum (Fabr.) on selected North American conifers

    Treesearch

    Jon Sweeney; Georgette Smith

    2003-01-01

    The brown spruce longhorn beetle, Tetropium fuscum (Fabr.) (Coleoptera: Cerambycidae), native to Europe, was recently discovered infesting and killing red spruce, Picea rubens Sarg. in Point Pleasant Park, Halifax, Nova Scotia.

  16. 75 FR 39691 - Announcement To Extend the Recommended Determination Preparation Period for the Spruce No. 1...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-12

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY Announcement To Extend the Recommended Determination Preparation Period for the Spruce No. 1... the Spruce No. 1 Proposed Determination or prepare a Recommended Determination within 30 days...

  17. Spruce budworm weight and fecundity: means, frequency distributions, and correlations for two populations (Lepidoptera: tortricidae)

    Treesearch

    Nancy Lorimer; Leah S. Bauer

    1983-01-01

    Pupal weights and fecundities of spruce budworm from Minnesota had different means, coefficients of variation, and frequency distributions than spruce budworm from New Hampshire. The two variables were correlated in one of the populations but not the other.

  18. Crustal structure of the eastern Qinling orogenic belt and implication for reactivation since the Cretaceous

    NASA Astrophysics Data System (ADS)

    Guo, Zhen; Chen, Y. John

    2016-06-01

    A high resolution crustal model of the eastern Qinling belt and central North China Craton (central NCC) is obtained along a N-S trending profile (corridor) by joint inversion of surface wave and receiver function. The NCC is one of the oldest cratons on Earth and the Qinling belt is the suture zone between the NCC and South China block (SCB). The Qinling belt is characterized by low crustal velocity (< 3.6 km/s) as well as low bulk Vp/Vs ratio (1.66-1.8), suggesting that the mid- to lower crust is predominantly felsic in composition, which could be the consequence of removal of mafic root by delamination in the past. The quartz-rich hence mechanically weak crust beneath the Qinling belt could be responsible for the strain focusing and significant reactivation since the Cretaceous. Beneath the central NCC, a 10 km thick high-velocity layer (3.9-4.1 km/s) is observed just above the Moho, consistent with the regional high bulk Vp/Vs ratio (> 1.8). The forward gravity modeling supports the presence of a high-density layer (3.05 g/cm3) at the base of the crust beneath the central NCC. We propose that the high velocity in the lowermost crust beneath the central NCC is most likely due to the repeated mafic underplating, which also results in high crustal Vp/Vs ratio and is responsible for the rapid crustal uplift during the late Mesozoic.

  19. Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Lampadariou, N.; Kalogeropoulou, V.; Sevastou, K.; Keklikoglou, K.; Sarrazin, J.

    2013-08-01

    Mud volcanoes are a~special type of cold seeps where life is based on chemoautotrophic processes. They are considered to be extreme environments and are characterized by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO (MEditerranean Deep-sea ECOsystems) cruise (2007) with the remotely operated vehicle (ROV) Victor-6000: Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field); and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Patterns of nematode diversity, the dominant meiofaunal taxon, varied, displaying both very high or very low species richness and dominance, depending on the microhabitat studied. The periphery of the Lamellibrachia and bivalve shell microhabitats of Napoli exhibited the highest species richness, while the reduced sediments of Amsterdam yielded a species-poor nematode community dominated by two successful species, one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that microhabitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold-seep ecosystems on the meiofaunal communities and nematode assemblages.

  20. Influence of chemosynthetic ecosystems on nematode community structure and biomass in the deep eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Lampadariou, N.; Kalogeropoulou, V.; Sevastou, K.; Keklikoglou, K.; Sarrazin, J.

    2012-12-01

    Mud volcanoes are a special type of cold seeps where life is based on chemoautotrophic processes. They are considered as extreme environments and are characterised by unique megafaunal and macrofaunal communities. However, very few studies on mud volcanoes taking into account the smaller meiobenthic communities have been carried out. Two mud volcanoes were explored during the MEDECO cruise (2007) with the Remotely Operated Vehicle (ROV) Victor-6000; Amsterdam, located south of Turkey between 1700 and 2000 m depth (Anaximander mud field) and Napoli, south of Crete, located along the Mediterranean Ridge at about 2000 m depth (Olimpi mud field). The major aim of this study was to describe distributional patterns of meiofaunal communities and nematode assemblages from different seep microhabitats. Meiofaunal taxa and nematode assemblages at both mud volcanoes differed significantly from other Mediterranean sites in terms of standing stocks, dominance and species diversity. Density and biomass values were significantly higher at the seep sites, particularly at Amsterdam. Nematodes, the dominant meiofaunal taxon, displayed deeper penetration vertically into the sediment at the seep areas, indicating that biological rather than physicochemical factors are responsible for their vertical distribution. Patterns of nematode diversity varied, displaying both very high or very low species richness and dominance, depending on the habitat studied. The Lamellibrachia periphery and mussel bed of Napoli exhibited the highest species richness while the reduced sediments of Amsterdam yielded a species-poor nematode community, dominated by two successful species; one belonging to the genus Aponema and the other to the genus Sabatieria. Analysis of β-diversity showed that habitat heterogeneity of mud volcanoes contributed substantially to the total nematode species richness in the eastern Mediterranean Sea. These observations indicate a strong influence of mud volcanoes and cold

  1. Paleoseismological analysis of an intraplate extensional structure: the Concud fault (Iberian Chain, eastern Spain)

    NASA Astrophysics Data System (ADS)

    Lafuente, P.; Arlegui, L. E.; Liesa, C. L.; Simón, J. L.

    2011-10-01

    The Concud fault is a 13.5 km long, NW-SE striking normal fault at the eastern Iberian Chain. Its recent (Late Pleistocene) slip history is characterized from mapping and trench analysis and discussed in the context of the accretion/incision history of the Alfambra River. The fault has been active since Late Pliocene times, with slip rates ranging from 0.07 to 0.33 mm/year that are consistent with its present-day geomorphologic expression. The most likely empirical correlation suggests that the associated paleoseisms have potential magnitudes close to 6.8, coseismic displacements of 2.0 m, and recurrence intervals from 6.1 to 28.9 ka. At least six paleoseismic events have been identified between 113 and 32 ka. The first three events (U to W) involved displacement along the major fault plane. The last three events (X to Z) encompassed downthrow and hanging-wall synthetic bending prompting fissure opening. This change is accompanied by a decrease in slip rate (from 0.63 to 0.08-0.17 mm/year) and has been attributed to activation of a synthetic blind fault at the hanging wall. The average coseismic displacement (1.9-2.0 m) and recurrence period (6.7-7.9 ka) inferred from this paleoseismic succession are within the ranges predicted from empirical correlation. Such paleoseismic activity contrasts with the moderate present-day seismicity of the area (maximum instrumental Mb = 4.4), which can be explained by the long recurrence interval that characterizes intraplate regions.

  2. Multi-scale variation in spatial heterogeneity for microbial community structure in an eastern Virginia agricultural field

    NASA Technical Reports Server (NTRS)

    Franklin, Rima B.; Mills, Aaron L.

    2003-01-01

    To better understand the distribution of soil microbial communities at multiple spatial scales, a survey was conducted to examine the spatial organization of community structure in a wheat field in eastern Virginia (USA). Nearly 200 soil samples were collected at a variety of separation distances ranging from 2.5 cm to 11 m. Whole-community DNA was extracted from each sample, and community structure was compared using amplified fragment length polymorphism (AFLP) DNA fingerprinting. Relative similarity was calculated between each pair of samples and compared using geostatistical variogram analysis to study autocorrelation as a function of separation distance. Spatial autocorrelation was found at scales ranging from 30 cm to more than 6 m, depending on the sampling extent considered. In some locations, up to four different correlation length scales were detected. The presence of nested scales of variability suggests that the environmental factors regulating the development of the communities in this soil may operate at different scales. Kriging was used to generate maps of the spatial organization of communities across the plot, and the results demonstrated that bacterial distributions can be highly structured, even within a habitat that appears relatively homogeneous at the plot and field scale. Different subsets of the microbial community were distributed differently across the plot, and this is thought to be due to the variable response of individual populations to spatial heterogeneity associated with soil properties. c2003 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

  3. Macro- and meso-fabric structures of peritidal tufa stromatolites along the Eastern Cape coast of South Africa

    NASA Astrophysics Data System (ADS)

    Edwards, Mark Joseph Kalahari; Anderson, Callum Robert; Perissinotto, Renzo; Rishworth, Gavin Midgley

    2017-08-01

    Stromatolites are rare in modern ecosystems due to factors associated with seawater chemistry or biological competition that restrict their formation. Actively calcifying stromatolites, near the Kei Mouth in the Eastern Cape, South Africa, were discovered in the early 2000s. Similar deposits were later described along a 200 km stretch on the south coast of Port Elizabeth. This study aims to describe the environmental setting, the macro- and meso-structures, as well as the evolution of the deposits near Port Elizabeth compared to other similar formations. Results show that the general environmental setting is consistent amongst peritidal stromatolites, including those described in this study. In all instances stromatolite growth occurs on a wave-cut rocky platform in and around rock pools. Growth is maximal within the intertidal to supratidal zone, as a result of freshwater inflow via emerging mineral springs at the base of landward slopes, and the periodic intrusion of seawater via storm surges or wave splash. In comparison with other systems, the South African stromatolite formations exhibit an additional macro-structure (beachrock/conglomerate) and four previously undescribed meso-structures: wrinkled laminar, laminar flat, rhizoliths, and blistered types. The South African stromatolites are also larger and more concentrated than other peritidal stromatolites, which could be due to this area having more suitable growth conditions.

  4. Continuity of subsurface fault structure revealed by gravity anomaly: the eastern boundary fault zone of the Niigata plain, central Japan

    NASA Astrophysics Data System (ADS)

    Wada, Shigeki; Sawada, Akihiro; Hiramatsu, Yoshihiro; Matsumoto, Nayuta; Okada, Shinsuke; Tanaka, Toshiyuki; Honda, Ryo

    2017-01-01

    We have investigated gravity anomalies around the Niigata plain, which is a sedimentary basin in central Japan bounded by mountains, to examine the continuity of subsurface fault structures of a large fault zone—the eastern boundary fault zone of the Niigata plain (EBFZNP). The features of the Bouguer anomaly and its first horizontal and vertical derivatives clearly illustrate the EBFZNP. The steep first horizontal derivative and the zero isoline of the vertical derivative are clearly recognized along the entire EBFZNP over an area that shows no surface topographic features of an active fault. Two-dimensional density structure analyses also confirm a relationship between the two first derivatives and the subsurface fault structure. Therefore, we conclude that the length of the EBFZNP as an active fault extends to 56 km, which is longer than previously estimated. This length leads to an estimation of a moment magnitude of 7.4 of an expected earthquake from the EBFZNP.[Figure not available: see fulltext.

  5. Subsurface structure of the eastern edge of the Zagros basin as inferred from gravity and satellite data

    SciTech Connect

    Bushara, M.N.

    1995-09-01

    A data set of 10,505 points of land gravity measurements from southeast Iran obtained from the Bureau Gravimetrique International, combined with Landsat imagery, was used to investigate crustal and Cenozoic lithospheric structure. Interpretation of the Bouguer anomalies reveals three primary structural features. The Zagros Mountain belt is characterized by a progressive decrease in gravity values from -70 mGal near the Persian Gulf to -160 mGal over the structure zone between the Arabian margin and central Iran crustal blocks. The second feature is marked by a backward-L-shaped pair of anomalies that extends from the eastern peripheries of the Zagros basin and wraps around southern Iranian shores. These 15- to 20-km-deep source anomalies, with amplitudes of as much as 10 mGal, are interpreted as intrabasement intrusions demarcating an ancient rift axis. The shallow (6-8)km east-west-trending anomalies are perhaps interbasement uplifts bordered by reverse faults. The third structure, observed on both gravity and Landsat displays, a north-striking eastward-facing topographic escarpment, has a gravity gradient of 0.85 mGal/km, and is right laterally offset approximately 100 km, and is right laterally offset approximately 100 km by the Zagros main recent fault. A comparison of gravity features with surface structures on Thematic Mapper and Landsat Multi-spectral Scanner imagery indicates that a northeast-trending fault system is the result of post-Miocene pervasive transpressive stress coupled with clockwise rotation of underlying basement blocks following the collision of Arabia and Iran. Accommodation structures such as forced folds and {open_quotes}rabbit-ear{close_quotes} anticlines may develop over and on the flanks of the basement blocks, providing remigration and trapping mechanisms for new oil and gas plays.

  6. Mechanical properties of spruce wood cell walls by nanoindentation

    NASA Astrophysics Data System (ADS)

    Gindl, W.; Gupta, H. S.; Schöberl, T.; Lichtenegger, H. C.; Fratzl, P.

    2004-12-01

    In order to study the effects of structural variability, nanoindentation experiments were performed in Norway spruce cell walls with highly variable cellulose microfibril angle and lignin content. Contrary to hardness, which showed no statistically significant relationship with changing microfibril angle and lignin content, the elastic modulus of the secondary cell wall decreased significantly with increasing microfibril angle. While the elastic moduli of cell walls with large microfibril angle agreed well with published values, the elastic moduli of cell walls with small microfibril angle were clearly underestimated in nanoindentation measurements. Hardness measurements in the cell corner middle lamella allowed us to estimate the yield stress of the cell-wall matrix to be 0.34±0.16 GPa. Since the hardness of the secondary cell wall was statistically not different from the hardness of the cell corner middle lamella, irrespective of high variability in cellulose microfibril angle, it is proposed that compressive yielding of wood-cell walls is a matrix-dominated process.

  7. Impact of Forest Harvesting on Trophic Structure of Eastern Canadian Boreal Shield Lakes: Insights from Stable Isotope Analyses

    PubMed Central

    Glaz, Patricia; Sirois, Pascal; Archambault, Philippe; Nozais, Christian

    2014-01-01

    Perturbations on ecosystems can have profound immediate effects and can, accordingly, greatly alter the natural community. Land-use such as forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. The objective of this study was to evaluate the impact of forest harvesting on trophic structure in eastern Canadian Boreal Shield lakes. We measured carbon and nitrogen stable isotopes values for aquatic primary producers, terrestrial detritus, benthic macroinvertebrates, zooplankton and brook trout (Salvelinus fontinalis) over a three-year period in eight eastern Boreal Shield lakes. Four lakes were studied before, one and two years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. Stable isotope mixing models showed leaf-litter to be the main food source for benthic primary consumers in both perturbed and unperturbed lakes, suggesting no logging impact on allochthonous subsidies to the littoral food web. Brook trout derived their food mainly from benthic predatory macroinvertebrates in unperturbed lakes. However, in perturbed lakes one year after harvesting, zooplankton appeared to be the main contributor to brook trout diet. This change in brook trout diet was mitigated two years after harvesting. Size-related diet shift were also observed for brook trout, indicating a diet shift related to size. Our study suggests that carbon from terrestrial habitat may be a significant contribution to the food web of oligotrophic Canadian Boreal Shield lakes. Forest harvesting did not have an impact on the diet of benthic primary consumers. On the other hand, brook trout diet composition was affected by logging with greater zooplankton contribution in perturbed lakes, possibly induced by darker-colored environment in these lakes one year after logging. PMID:24763366

  8. Impact of forest harvesting on trophic structure of eastern Canadian Boreal Shield lakes: insights from stable isotope analyses.

    PubMed

    Glaz, Patricia; Sirois, Pascal; Archambault, Philippe; Nozais, Christian

    2014-01-01

    Perturbations on ecosystems can have profound immediate effects and can, accordingly, greatly alter the natural community. Land-use such as forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. The objective of this study was to evaluate the impact of forest harvesting on trophic structure in eastern Canadian Boreal Shield lakes. We measured carbon and nitrogen stable isotopes values for aquatic primary producers, terrestrial detritus, benthic macroinvertebrates, zooplankton and brook trout (Salvelinus fontinalis) over a three-year period in eight eastern Boreal Shield lakes. Four lakes were studied before, one and two years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. Stable isotope mixing models showed leaf-litter to be the main food source for benthic primary consumers in both perturbed and unperturbed lakes, suggesting no logging impact on allochthonous subsidies to the littoral food web. Brook trout derived their food mainly from benthic predatory macroinvertebrates in unperturbed lakes. However, in perturbed lakes one year after harvesting, zooplankton appeared to be the main contributor to brook trout diet. This change in brook trout diet was mitigated two years after harvesting. Size-related diet shift were also observed for brook trout, indicating a diet shift related to size. Our study suggests that carbon from terrestrial habitat may be a significant contribution to the food web of oligotrophic Canadian Boreal Shield lakes. Forest harvesting did not have an impact on the diet of benthic primary consumers. On the other hand, brook trout diet composition was affected by logging with greater zooplankton contribution in perturbed lakes, possibly induced by darker-colored environment in these lakes one year after logging.

  9. Population structure and phylogeography reveal pathways of colonization by a migratory marine reptile (Chelonia mydas) in the central and eastern Pacific.

    PubMed

    Dutton, Peter H; Jensen, Michael P; Frey, Amy; LaCasella, Erin; Balazs, George H; Zárate, Patricia; Chassin-Noria, Omar; Sarti-Martinez, Adriana Laura; Velez, Elizabeth

    2014-11-01

    Climate, behavior, ecology, and oceanography shape patterns of biodiversity in marine faunas in the absence of obvious geographic barriers. Marine turtles are an example of highly migratory creatures with deep evolutionary lineages and complex life histories that span both terrestrial and marine environments. Previous studies have focused on the deep isolation of evolutionary lineages (>3 mya) through vicariance; however, little attention has been given to the pathways of colonization of the eastern Pacific and the processes that have shaped diversity within the most recent evolutionary time. We sequenced 770 bp of the mtDNA control region to examine the stock structure and phylogeography of 545 green turtles from eight different rookeries in the central and eastern Pacific. We found significant differentiation between the geographically separated nesting populations and identified five distinct stocks (F ST = 0.08-0.44, P < 0.005). Central and eastern Pacific Chelonia mydas form a monophyletic group containing 3 subclades, with Hawaii more closely related to the eastern Pacific than western Pacific populations. The split between sampled central/eastern and western Pacific haplotypes was estimated at around 0.34 mya, suggesting that the Pacific region west of Hawaii has been a more formidable barrier to gene flow in C. mydas than the East Pacific Barrier. Our results suggest that the eastern Pacific was colonized from the western Pacific via the Central North Pacific and that the Revillagigedos Islands provided a stepping-stone for radiation of green turtles from the Hawaiian Archipelago to the eastern Pacific. Our results fit with a broader paradigm that has been described for marine biodiversity, where oceanic islands, such as Hawaii and Revillagigedo, rather than being peripheral evolutionary "graveyards", serve as sources and recipients of diversity and provide a mechanism for further radiation.

  10. Population structure and phylogeography reveal pathways of colonization by a migratory marine reptile (Chelonia mydas) in the central and eastern Pacific

    PubMed Central

    Dutton, Peter H; Jensen, Michael P; Frey, Amy; LaCasella, Erin; Balazs, George H; Zárate, Patricia; Chassin-Noria, Omar; Sarti-Martinez, Adriana Laura; Velez, Elizabeth

    2014-01-01

    Climate, behavior, ecology, and oceanography shape patterns of biodiversity in marine faunas in the absence of obvious geographic barriers. Marine turtles are an example of highly migratory creatures with deep evolutionary lineages and complex life histories that span both terrestrial and marine environments. Previous studies have focused on the deep isolation of evolutionary lineages (>3 mya) through vicariance; however, little attention has been given to the pathways of colonization of the eastern Pacific and the processes that have shaped diversity within the most recent evolutionary time. We sequenced 770 bp of the mtDNA control region to examine the stock structure and phylogeography of 545 green turtles from eight different rookeries in the central and eastern Pacific. We found significant differentiation between the geographically separated nesting populations and identified five distinct stocks (FST = 0.08–0.44, P < 0.005). Central and eastern Pacific Chelonia mydas form a monophyletic group containing 3 subclades, with Hawaii more closely related to the eastern Pacific than western Pacific populations. The split between sampled central/eastern and western Pacific haplotypes was estimated at around 0.34 mya, suggesting that the Pacific region west of Hawaii has been a more formidable barrier to gene flow in C. mydas than the East Pacific Barrier. Our results suggest that the eastern Pacific was colonized from the western Pacific via the Central North Pacific and that the Revillagigedos Islands provided a stepping-stone for radiation of green turtles from the Hawaiian Archipelago to the eastern Pacific. Our results fit with a broader paradigm that has been described for marine biodiversity, where oceanic islands, such as Hawaii and Revillagigedo, rather than being peripheral evolutionary “graveyards”, serve as sources and recipients of diversity and provide a mechanism for further radiation. PMID:25540693

  11. Lithospheric structure of the eastern flank of the Rio Grande Rift via receiver function velocity analysis

    NASA Astrophysics Data System (ADS)

    Agrawal, M.; Pulliam, J.; Sen, M. K.; Grand, S.

    2015-12-01

    To better delineate a seismic anomaly beneath the eastern flank of the Rio Grande Rift identified by seismic tomography, we depth-migrated Ps and Sp receiver functions using data from the SIEDCAR (Seismic Investigation of Edge Driven Convection Association with Rio Grande Rift) and USArray Transportable Array (TA) deployments. We performed Common Conversion Point (CCP) stacking to improve the S/N ratio of receiver functions. Using an incorrect velocity model for depth migration of a stacked CCP image may generate an inaccurate picture of the subsurface. To find sufficiently accurate P- and S-velocity models for migration, we optimize the average correlation value of common receiver gathers for target features - in this case the Moho and the LAB - while perturbing the shear wave velocities in a process driven by simulated annealing. The technique simultaneously finds depths to major discontinuities (in this case the Moho and LAB) and S and P velocity profiles beneath each seismic station in a manner that is similar to velocity analysis in reflection seismology. An application to data acquired in southeastern New Mexico and west Texas, at an average station spacing of 35 km, reveals an abrupt increase in lithospheric thickness from west to east, from the Rio Grande Rift to the Great Plains craton. Previous studies found an elongated high velocity anomaly that extends to depths approaching 500 km in southeastern New Mexico and west Texas that is distinct from the thick Great Plains lithosphere. Our stacked 3-D image confirms the anomaly's existence and shows that it is more laterally extensive than was previously indicated. Recent numerical modeling suggests that an abrupt change in lithospheric thickness, which creates a step change in densities, may produce a gravitational instability that leads to thicker mantle lithosphere dripping off into the lower density asthenosphere. As the mantle deforms it alternately thickens and thins the crust, producing topographic

  12. 3D anisotropic surface wave and shear wave velocity structure beneath Eastern Tibet

    NASA Astrophysics Data System (ADS)

    Ceylan, S.; Ni, J. F.; Chen, Y. J.; Tilmann, F. J.; Sandvol, E. A.

    2011-12-01

    Recent studies have suggested that uplift of the northern Tibetan plateau may be related to removal of lithospheric mantle, resulting in emplacement of hotter, less dense asthenosphere. Other studies propose that plateau uplift and crustal thickening have occurred through a process of lateral mid-crustal flow or coherent deformation between crust and lithospheric mantle. Some authors attribute the geophysical properties of upper mantle beneath the plateau to either delamination of thickened lithosphere, or asthenospheric counterflow associated with subduction of continental Indian lithosphere beneath central Tibet. In order to study the evolution and dynamics of the Tibetan plateau, we deployed 74 broadband seismic stations throughout northeastern Tibet within the scope of ASCENT/INDEPTH-IV experiment. In conjunction with Namche Barwa data, we have calculated fundamental mode Rayleigh wave phase velocities utilizing two-plane wave approach, for periods between 20-143 seconds. We also obtained preliminary phase velocities using Love waves. To invert for shear wave velocities, we use partial derivatives from Saito (1988), assuming a constant Poisson's ratio. Our azimuthal anisotropy measurements agree well with SKS splitting results; both indicate significant (>2%) average azimuthal anisotropy throughout the upper mantle down to depths exceeding 250 km, with a dominantly EW fast directions. Although we observe variations of fast directions with depth, they are generally consistent (i.e., within 15 degrees) up to ~200 km, indicative of vertically coherent deformation. Furthermore at crustal depths, azimuthal fast directions tend be sub-parallel to the strikes of major strike slip faults, suggesting that shearing is the dominant deformation mechanism in eastern Tibet. Our tomographic models show an uppermost mantle low velocity anomaly north of Bangong-Nujiang Suture (BNS) in northeastern Tibet, and a high velocity anomaly extending ~200 km centered on the BNS. We

  13. Pervasive growth reduction in Norway spruce forests following wind disturbance.

    PubMed

    Seidl, Rupert; Blennow, Kristina

    2012-01-01

    In recent decades the frequency and severity of natural disturbances by e.g., strong winds and insect outbreaks has increased considerably in many forest ecosystems around the world. Future climate change is expected to further intensify disturbance regimes, which makes addressing disturbances in ecosystem management a top priority. As a prerequisite a broader understanding of disturbance impacts and ecosystem responses is needed. With regard to the effects of strong winds--the most detrimental disturbance agent in Europe--monitoring and management has focused on structural damage, i.e., tree mortality from uprooting and stem breakage. Effects on the functioning of trees surviving the storm (e.g., their productivity and allocation) have been rarely accounted for to date. Here we show that growth reduction was significant and pervasive in a 6.79 million hectare forest landscape in southern Sweden following the storm Gudrun (January 2005). Wind-related growth reduction in Norway spruce (Picea abies (L.) Karst.) forests surviving the storm exceeded 10% in the worst hit regions, and was closely related to maximum gust wind speed (R(2) = 0.849) and structural wind damage (R(2) = 0.782). At the landscape scale, wind-related growth reduction amounted to 3.0 million m(3) in the three years following Gudrun. It thus exceeds secondary damage from bark beetles after Gudrun as well as the long-term average storm damage from uprooting and stem breakage in Sweden. We conclude that the impact of strong winds on forest ecosystems is not limited to the immediately visible area of structural damage, and call for a broader consideration of disturbance effects on ecosystem structure and functioning in the context of forest management and climate change mitigation.

  14. Pervasive Growth Reduction in Norway Spruce Forests following Wind Disturbance

    PubMed Central

    Seidl, Rupert; Blennow, Kristina

    2012-01-01

    Background In recent decades the frequency and severity of natural disturbances by e.g., strong winds and insect outbreaks has increased considerably in many forest ecosystems around the world. Future climate change is expected to further intensify disturbance regimes, which makes addressing disturbances in ecosystem management a top priority. As a prerequisite a broader understanding of disturbance impacts and ecosystem responses is needed. With regard to the effects of strong winds – the most detrimental disturbance agent in Europe – monitoring and management has focused on structural damage, i.e., tree mortality from uprooting and stem breakage. Effects on the functioning of trees surviving the storm (e.g., their productivity and allocation) have been rarely accounted for to date. Methodology/Principal Findings Here we show that growth reduction was significant and pervasive in a 6.79·million hectare forest landscape in southern Sweden following the storm Gudrun (January 2005). Wind-related growth reduction in Norway spruce (Picea abies (L.) Karst.) forests surviving the storm exceeded 10% in the worst hit regions, and was closely related to maximum gust wind speed (R2 = 0.849) and structural wind damage (R2 = 0.782). At the landscape scale, wind-related growth reduction amounted to 3.0 million m3 in the three years following Gudrun. It thus exceeds secondary damage from bark beetles after Gudrun as well as the long-term average storm damage from uprooting and stem breakage in Sweden. Conclusions/Significance We conclude that the impact of strong winds on forest ecosystems is not limited to the immediately visible area of structural damage, and call for a broader consideration of disturbance effects on ecosystem structure and functioning in the context of forest management and climate change mitigation. PMID:22413012

  15. Decline of red spruce in the Adirondacks, New York

    SciTech Connect

    Scott, J.T.; Siccama, T.G.; Johnson, A.H.; Breisch, A.R.

    1984-01-01

    Thirty-two stands in the spruce-fir forests of Whiteface Mountain in the Adirondacks, originally sampled from 1964-66, were resurveyed in 1982. From 10-25 Bitterlich points were used in each stand in 1982 to obtain an estimate of basal area per hectare. Data were summarized for low elevation (<900m) and high elevation (> or = 900m) forests. Red spruce declined by 40-60% in basal area for the low elevation forests and by 60-70% above 900m. Balsam fir decreased by 35% at high elevations, due to natural disturbance in several of the stands, but was unchanged when only undisturbed stands were considered. The decline of red spruce accounted for about three quarters of the total decrease in basal area for both the high- and low-elevation forests. Spruce seedling frequency for the high-elevation sample decreased by 80%, but was unchanged below 900m. The pattern of spruce decline in the Adirondacks is similar to findings for New England. The cause of the decline is speculative at the time.

  16. Mathematical Methods of Modelling the Morphology of Spruce Trees

    NASA Astrophysics Data System (ADS)

    Janoutová, Růžena; Novotný, Jan; Pivovarník, Marek; Zemek, František

    2014-05-01

    Radiative transfer (RT) models are simulation tools which can be used to quantify relationships between vegetation canopy properties and observed remotely sensed data. This study aims at creating a spruce tree growth model as a key input for use in RT models. The spruce tree model is built on data obtained from terrestrial laser scanning of spruce trees. Each tree model is unique. This uniqueness is achieved by using L-systems which are able to simulate natural randomness while complying with the given tree parameters. L-systems are established on a theory of grammar that enables rewriting a string of symbols according to specified rewriting rules. In practice, our tree models are generated in Blender visualization software, implementing an algorithm written in Python. The algorithm generates the basic parameters of the whole tree and then creates the parameters of the spruce trunk and initial branches. The parameters are generated randomly within a range that is calculated from measured data. Then each branch is grown on the basis of annual increments defined by field measurements. Tree needles are distributed with respect to the age of individual branches; therefore, the needles have different colors according to their age. Cones and faces are graphical representations of the spruce model. Branches are represented by cones and needles are represented by faces around the branches. The faces are transparent, thus simulating light transmittance in-between the needles. The whole model is highly computationally demanding, especially with respect to computer memory.

  17. Effects of forest management legacies on spruce budworm (Choristoneura fumiferana) outbreaks

    Treesearch

    Louis-Etienne Robert; Daniel Kneeshaw; Brian R. Sturtevant

    2012-01-01

    The "silvicultural hypothesis" of spruce budworm (Choristoneura fumiferana Clem.) dynamics postulates that increasing severity of spruce budworm outbreaks over the last century resulted from forest conditions created by past management activities. Yet, definitive tests of the hypothesis remain elusive. We examined spruce budworm outbreak...

  18. Release of Suppressed Red Spruce Using Canopy Gap Creation--Ecological Restoration in the Central Appalachians

    Treesearch

    J.S. Rentch; W.M. Ford; Thomas Schuler; Jeff Palmer; C.A. Diggins

    2016-01-01

    Red spruce (Picea rubens) and red spruce-northern hardwood mixed stands once covered as much as 300,000 ha in the Central Appalachians, but now comprise no more than 21,000 ha. Recently, interest in restoration of this forest type has increased because red spruce forests provide habitat for a number of rare animal species. Our study reports the...

  19. Spruce aphid in high elevation habitats in the Southwest U.S.

    Treesearch

    Ann M. Lynch

    2003-01-01

    Spruce aphid, Elatobium abietinum (Walker) (Homoptera: Aphididae), is a new invasive pest in the interior Southwestern United States. This insect is causing extensive and severe damage on dormant Engelmann spruce, Picea engelmannii Parry, and Colorado blue spruce, P. pungens Engelm., in high elevation forests in...

  20. The current distribution, predictive modeling, and restoration potential of red spruce in West Virginia

    Treesearch

    Gregory Nowacki; Dan. Wendt

    2010-01-01

    The environmental relationships of red spruce (Picea rubens Sarg.) were assessed in east-central West Virginia. Although many significant relationships existed, red spruce was most strongly associated with elevation, climate, and soil moisture factors. Specifically, red spruce was positively associated with elevation, number of frost days, mean...

  1. Photosynthesis in black and red spruce and their hybrid derivatives: ecological isolation and hybrid adaptive inferiority

    Treesearch

    S.A.M Manley; F. Thomas Ledig

    1979-01-01

    Photosynthetic response5 of black and red spruce were used to define parameters of their fundamental niches. Grown at warm temperature, black spruce had highest rates of CO2 uptake at high light intensities, fitting it for a pioneering role, while red spruce had the lowest light compensation point, fitting it for a late successional role. Black...

  2. Comparison of naturally and synthetically baited spruce beetle trapping systems in the central Rocky Mountains

    Treesearch

    E. Matthew Hansen; Jim C. Vandygriff; Robert J. Cain; David Wakarchuk

    2006-01-01

    We compared naturally baited trapping systems to synthetically baited funnel traps and fallen trap trees for suppressing preoutbreak spruce beetle, Dendroctonus rufipennis Kirby, populations. Lures for the traps were fresh spruce (Picea spp.) bolts or bark sections, augmented by adding female spruce beetles to create secondary attraction. In 2003, we...

  3. Group velocity dispersion characteristics and one-dimensional regional shear velocity structure of the eastern Indian craton

    NASA Astrophysics Data System (ADS)

    Mandal, Prantik

    2017-02-01

    In the past three years, a semi-permanent network of fifteen 3-component broadband seismographs has become operational in the eastern Indian shield region occupying the Archean (∼2.5-3.6 Ga) Singhbhum-Odisha craton (SOC) and the Proterozoic (∼1.0-2.5 Ga) Chotanagpur Granitic Gneissic terrane (CGGT). The reliable and accurate broadband data for the recent 2015 Nepal earthquake sequence from 10 broadband stations of this network enabled us to estimate the group velocity dispersion characteristics and one-dimensional regional shear velocity structure of the region. First, we measure fundamental mode Rayleigh- and Love-wave group velocity dispersion curves in the period range of 7-70 s and then invert these curves to estimate the crustal and upper mantle structure below the eastern Indian craton (EIC). We observe that group velocities of Rayleigh and Love waves in SOC are relatively high in comparison to those of CGGT. This could be attributed to a relatively mafic-rich crust-mantle structure in SOC resulting from two episodes of magmatism associated with the 1.6 Ga Dalma and ∼117 Ma Rajmahal volcanisms. The best model for the EIC from the present study is found to be a two-layered crust, with a 14-km thick upper-crust (UC) of average shear velocity (Vs) of 3.0 km/s and a 26-km thick lower-crust (LC) of average Vs of 3.6 km/s. The present study detects a sharp drop in Vs (∼-2 to 3%) at 120-260 km depths, underlying the EIC, representing the probable seismic lithosphere-asthenosphere boundary (LAB) at 120 km depth. Such sharp fall in Vs below the LAB indicates a partially molten layer. Further, a geothermal gradient extrapolated from the surface heat flow shows that such a gradient would intercept the wet basalt solidus at 88-103 km depths, suggesting a 88-103 km thick thermal lithosphere below the EIC. This could also signal the presence of small amounts of partial melts. Thus, this 2-3% drop in Vs could be attributed to the presence of partial melts in the

  4. Genetic host-tree effects on the ectomycorrhizal community and root characteristics of Norway spruce.

    PubMed

    Velmala, S M; Rajala, T; Haapanen, M; Taylor, A F S; Pennanen, T

    2013-01-01

    A greenhouse experiment was used to study the effects of host genotype on short root formation and ectomycorrhizal (ECM) fungal community structure in Norway spruce (Picea abies (L.) Karst.). Rooted cuttings representing 55 clones were inoculated with a mix of vegetative hyphae of five ECM fungal species (Laccaria sp., Amphinema byssoides, Piloderma sp., Cadophora finlandia, Paxillus involutus). After one growing season, the ECM fungal community structure was determined by amplifying the fungal internal transcribed spacer (ITS) of ribosomal DNA directly from ECM root tips. Restriction profiles of obtained amplicons were then compared to those of the inoculated strains. Spruce clones differed in their ECM fungal community composition; we found a statistically significant clone-specific effect on ECM fungal diversity and dominating fungal species. Nevertheless, the broad sense heritabilities of the levels of Laccaria sp., Piloderma sp. and A. byssoides colonisations as well as the ECM fungal community structure were low (H(2) = 0.04-0.11), owing to the high within-clone variation. As nitrogen concentration of needles correlated negatively with ECM fungal richness, our results imply that in the experimental conditions nutrient acquisition of young trees may benefit from colonisation with only one or two ECM fungal species. The heritability of short root density was moderate (H(2) = 0.41) and highest among all the measured shoot and root growth characteristics of Norway spruce cuttings. We suggest that the genetic component determining root growth and short root formation is significant for the performance of young trees in natural environments as these traits drive the formation of the below-ground symbiotic interactions.

  5. Crustal structure and magnetic lineation along two geo-traverses from western continental margin of India to Eastern Somali Basin, NW Indian Ocean

    NASA Astrophysics Data System (ADS)

    Chaubey, A. K.; Anshu, A.; Sreejith, K.; Pandey, A.

    2012-12-01

    Shipborne gravity and magnetic data along two parallel geo-traverses spanning from western continental margin of India to off Seychelles are used to delineate crustal structure and magnetic pattern of major structural features - western continental margin of India, Laxmi Basin, Laxmi Ridge, Arabian Basin, slow spreading Carlsberg Ridge and Eastern Somali Basin. The seismically constrained gravity models along the geo-traverses suggest considerable variation in crustal thickness - about 38 km on continental shelf of western India to about 4 km of the Eastern Somali Basin. The Eastern Somali Basin is characterized by thin oceanic crustal thickness (~3 to 4 km) as compared to its conjugate Arabian Basin where thickness varies from 5 to 6 km. The magnetic anomalies along the geo-traverse reveal three distinct zones: (i) a zone of relative high frequency short wavelength younger anomalies over the axial parts of the Carlsberg Ridge, (ii) a zone of well developed Early Tertiary magnetic anomalies in both the Arabian and Eastern Somali basins, and (iii) relative magnetic quiet zone, between the above two zones, representing a hiatus in spreading. Based on the results, we present a comparative analysis of crustal configuration and magnetic pattern of major structural features of the study area and discuss its tectonic evolution.

  6. Integrated study of seismic and gravity data on the crustal structure across the Longmenshan range, eastern Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Xu, X.; Keller, G. R.; Gao, R.; Guo, X.; Wang, H.; Li, W.; Zhu, X.

    2013-12-01

    The mechanism for the uplift of the Tibetan plateau is still a matter of debate. There are two main models, 1) extrusion and 2) lower crustal flow. These two models have been tested by surface observations, but some defects are remained. The 2008 Ms 7.9 Wenchuan earthquake along the Longmenshan fault zone reminded us that the tectonic activity within the eastern Tibetan Plateau is complex and is accompanied by the dramatic uplift of the Longmen Shan fault zone, which is more than 0.5-0.6 mm/a since 10 Ma B.P. With support of SinoProbe-02, we collected reflection and refraction seismic data that are distributed from Sichuan basin to Ruo'ergai basin in 2011, and combined them with gravity and other previous research. In this effort, our goal is to determine the crustal structure across the Longmenshan fault zone via an integrated analysis of seismic and gravity data and to propose a crustal structure model to account for the uplift.

  7. Changes in soil microbial community structure following the abandonment of agricultural terraces in mountainous areas of Eastern Spain

    PubMed Central

    Zornoza, R.; Guerrero, C.; Mataix-Solera, J.; Scow, K.M.; Arcenegui, V.; Mataix-Beneyto, J.

    2012-01-01

    In Eastern Spain, almond trees have been cultivated in terraced orchards for centuries, forming an integral part of the Mediterranean forest scene. In the last decades, orchards have been abandoned due to changes in society. This study investigates effects of changes in land use from forest to agricultural land and the posterior land abandonment on soil microbial community, and the influence of soil physico-chemical properties on the microbial community composition (assessed as abundances of phospholipids fatty acids, PLFA). For this purpose, three land uses (forest, agricultural and abandoned agricultural) at four locations in SE Spain were selected. Multivariate analysis showed a substantial level of differentiation in microbial community structure according to land use. The microbial communities of forest soils were highly associated with soil organic matter content. However, we have not found any physical or chemical soil property capable of explaining the differences between agricultural and abandoned agricultural soils. Thus, it was suggested that the cessation of the perturbation caused by agriculture and shifts in vegetation may have led to changes in the microbial community structure. PLFAs indicative of fungi and ratio of fungal to bacterial PLFAs were higher in abandoned agricultural soils, whereas the relative abundance of bacteria was higher in agricultural soils. Actinomycetes were generally lower in abandoned agricultural soils, while the proportions of vesicular-arbuscular mycorrhyzal fungi were, as a general trend, higher in agricultural and abandoned agricultural soils than in forests. Total microbial biomass and richness increased as agricultural < abandoned agricultural < forest soils. PMID:22291451

  8. The influence of habitat structure on genetic differentiation in red fox populations in north-eastern Poland.

    PubMed

    Mullins, Jacinta; McDevitt, Allan D; Kowalczyk, Rafał; Ruczyńska, Iwona; Górny, Marcin; Wójcik, Jan M

    2014-01-01

    The red fox (Vulpes vulpes) has the widest global distribution among terrestrial carnivore species, occupying most of the Northern Hemisphere in its native range. Because it carries diseases that can be transmitted to humans and domestic animals, it is important to gather information about their movements and dispersal in their natural habitat but it is difficult to do so at a broad scale with trapping and telemetry. In this study, we have described the genetic diversity and structure of red fox populations in six areas of north-eastern Poland, based on samples collected from 2002-2003. We tested 22 microsatellite loci isolated from the dog and the red fox genome to select a panel of nine polymorphic loci suitable for this study. Genetic differentiation between the six studied populations was low to moderate and analysis in Structure revealed a panmictic population in the region. Spatial autocorrelation among all individuals showed a pattern of decreasing relatedness with increasing distance and this was not significantly negative until 93 km, indicating a pattern of isolation-by-distance over a large area. However, there was no correlation between genetic distance and either Euclidean distance or least-cost path distance at the population level. There was a significant relationship between genetic distance and the proportion of large forests and water along the Euclidean distances. These types of habitats may influence dispersal paths taken by red foxes, which is useful information in terms of wildlife disease management.

  9. Lithospheric Structure in Eastern Africa and the Arabian Plate from Joint Inversion of Surface Wave Dispersion Data and Receiver Functions

    NASA Astrophysics Data System (ADS)

    Dugda, M. T.; Nyblade, A. A.; Rodgers, A.; Al-Amri, A.; Julia, J.

    2006-12-01

    Lithospheric structure beneath Eastern Africa (Ethiopia, Kenya, and Djibouti) and the Arabian Shield and Platform has been investigated using a joint inversion of receiver functions and surface wave dispersion measurements from 10 to 175 s. Our models help to constrain the extent of modification made to the lithosphere in the region by hotspot tectonism. Most of the data for this study come from three major sources: the Ethiopia and Kenya Broadband Seismic Experiments which were carried out between 2000-2002 and 2001-2002, respectively, and data from the Saudi Arabia National Digital Seismic Network (KACST). We find that there is little or no seismic lid under the Main Ethiopian Rift and Afar. The results for the Ethiopian Plateau show that there has been thinning of the lithosphere by about ~30 40 km from typical Mozambique Belt lithosphere under Tanzania, which was reported to be up to 120 km thick, and that there has been a reduction in maximum shear wave velocity of the lid by about 7%. Replacement of the bottom of the former Mozambique Belt lithosphere by warm plume material with a partial erosion of the lithosphere can explain both the thinning of the lithosphere and the reduction of maximum velocity. Preliminary results suggest similar lithospheric structure beneath the Arabian Shield. The results from Kenya are similar to that of the results for the Mozambique Belt Lithosphere in Tanzania, showing 100-120 km thick lithosphere.

  10. Changes in soil microbial community structure following the abandonment of agricultural terraces in mountainous areas of Eastern Spain.

    PubMed

    Zornoza, R; Guerrero, C; Mataix-Solera, J; Scow, K M; Arcenegui, V; Mataix-Beneyto, J

    2009-07-01

    In Eastern Spain, almond trees have been cultivated in terraced orchards for centuries, forming an integral part of the Mediterranean forest scene. In the last decades, orchards have been abandoned due to changes in society. This study investigates effects of changes in land use from forest to agricultural land and the posterior land abandonment on soil microbial community, and the influence of soil physico-chemical properties on the microbial community composition (assessed as abundances of phospholipids fatty acids, PLFA). For this purpose, three land uses (forest, agricultural and abandoned agricultural) at four locations in SE Spain were selected. Multivariate analysis showed a substantial level of differentiation in microbial community structure according to land use. The microbial communities of forest soils were highly associated with soil organic matter content. However, we have not found any physical or chemical soil property capable of explaining the differences between agricultural and abandoned agricultural soils. Thus, it was suggested that the cessation of the perturbation caused by agriculture and shifts in vegetation may have led to changes in the microbial community structure. PLFAs indicative of fungi and ratio of fungal to bacterial PLFAs were higher in abandoned agricultural soils, whereas the relative abundance of bacteria was higher in agricultural soils. Actinomycetes were generally lower in abandoned agricultural soils, while the proportions of vesicular-arbuscular mycorrhyzal fungi were, as a general trend, higher in agricultural and abandoned agricultural soils than in forests. Total microbial biomass and richness increased as agricultural < abandoned agricultural < forest soils.

  11. Geology, structure, geochemistry and ASTER-based mapping of Neoproterozoic Gebel El-Delihimmi granites, Central Eastern Desert of Egypt

    NASA Astrophysics Data System (ADS)

    Asran, Asran Mohamed; Emam, Ashraf; El-Fakharani, Abdelhamid

    2017-06-01

    The Gebel El-Delihimmi granite intrusion, located in the Central Eastern Desert of Egypt, cuts the core of a major anticlinal structure of calc-alkaline metavolcanics and ophiolitic mélange rocks. The intrusion is microscopically differentiated into granodiorite, monzogranite, syenogranite and alkali-feldspar granite. Decorrelation stretch and band-ratio techniques were applied to Advanced Spaceborne Thermal Emission and Reflection Radiometer data. Processing of ASTER-SWIR bands enabled discrimination of El-Delihimmi granite phases and generation of a detailed lithologic map of the study area. The structural and microfabric data suggest that the El-Delihimmi granite underwent at least two phases of deformations. The first was related to the Najd fault system during which the older granodiorite phase of the intrusion was affected by sinistral ductile shearing. During the second phase, monzogranite and syenogranite in the intrusion were affected by brittle E-W compressional deformation. Geochemical data reported here reveal that the granodiorite phase has K2O/Na2O ratio < 1 and represents an evolved calc-alkaline granite. The monzogranite, syenogranite and alkali-feldspar granite phases have K2O/Na2O ratio > 1. The granite phases are generally I-type, metaluminous to slightly peraluminous and are interpreted as formed above subducted slabs of oceanic lithosphere rather than in continental collision zones.

  12. Daily precipitation and tropical moisture exports across the eastern United States: an application of archetypal analysis to identify spatiotemporal structure

    NASA Astrophysics Data System (ADS)

    Steinschneider, S.; Lall, U.

    2015-12-01

    This study examines the spatiotemporal variability of two sets of daily precipitation from the ERA-Interim reanalysis across the eastern United States between 1979-2013: 1) total precipitation, and 2) precipitation originating from tropical moisture exports (TMEs), which have been linked to extremes of midlatitude precipitation. We introduce archetypal analysis (AA) as a new method to decompose and characterize structures within the spatiotemporal climate data. AA is uniquely suited to identify extremal patterns and is a complementary method to Empirical Orthogonal Function (EOF) analysis. We provide a brief comparison between AA and EOF analysis and then examine the spatiotemporal variability, circulation anomalies, and sea surface temperature teleconnections associated with the archetypes of the two precipitation variables. Markovian structure, seasonal variability, and inter-annual trends in archetype occurrence are explored using nonparametric generalized linear models (GLMs). Results show that the modes of precipitation variability and their associated teleconnections are very similar between total and TME precipitation, suggesting that TMEs can help explain prevailing modes of total precipitation variability. Both total and TME precipitation shift longitudinally conditional on the phase of the Pacific Decadal Oscillation (PDO) and sea surface temperatures in the North Atlantic, and they are inhibited during strong, negative PDO and positive Atlantic Multidecadal Oscillation (AMO) regimes. The GLM analysis reveals distinct seasonal cycles and decadal trends in archetypes likely associated with the strength and position of the North Atlantic Subtropical High (NASH).

  13. Variation of Crustal Shear Velocity Structure Along the Eastern Lau Back-Arc Spreading Center Constrained By Seafloor Compliance

    NASA Astrophysics Data System (ADS)

    Zha, Y.; Webb, S. C.; Dunn, R. A.

    2014-12-01

    Measurements of seafloor compliance, the deformation under long period (typically 30-300 s) ocean wave forcing, are primarily sensitive to crustal shear velocity structure. We analyze seafloor compliance from data collected from a subset of 50 broadband Ocean Bottom Seismographs (OBS) deployed at the Eastern Lau spreading center (ELSC) from 2009 to 2010. The ELSC is a 400-km-long back-arc spreading center lying closely to the Tonga subduction trench in the southwestern Pacific. Seafloor morphology, crustal seismic structure and lava composition data show rapid variations along the ridge as the ridge migrates away from the volcanic arc front to the north, indicating a decreasing influence of the subducting slab. We calculate seafloor compliance functions by taking the spectral transfer function between the vertical displacement and pressure signal recorded by the 4-component OBSs, which are equipped with differential pressure gauges (DPGs). In the ridge perpendicular direction, compliance amplitude vary by more than an order of magnitude from the ridge crest to older seafloor covered by sediment. Along the spreading ridge, compliance measured from on-axis sites increases southwards, indicative of a decrease in the upper crustal shear velocity possibly due to increasing porosity and a thickening extrusive layer [Jacobs et al., 2007; Dunn et al., 2013]. We apply a Markov Chain Monte Carlo method to invert the compliance functions for crustal shear velocities at various locations along the ELSC.

  14. Experimental warming delays autumn senescence in a boreal spruce bog: Initial results from the SPRUCE experiment

    NASA Astrophysics Data System (ADS)

    Richardson, Andrew; Furze, Morgan; Aubrecht, Donald; Milliman, Thomas; Nettles, Robert; Krassovski, Misha; Hanson, Paul

    2016-04-01

    Phenology is considered one of the most robust indicators of the biological impacts of global change. In temperate and boreal regions, long-term data show that rising temperatures are advancing spring onset (e.g. budburst and flowering) and delaying autumn senescence (e.g. leaf coloration and leaf fall) in a wide range of ecosystems. While warm and cold temperatures, day length and insolation, precipitation and water availability, and other factors, have all been shown to influence plant phenology, the future response of phenology to rising temperatures and elevated CO2 still remains highly uncertain because of the challenges associated with conducting realistic manipulative experiments to simulate future environmental conditions. At the SPRUCE (Spruce and Peatland Responses Under Climatic and Environmental Change) experiment in the north-central United States, experimental temperature (0 to +9° C above ambient) and CO2 (ambient and elevated) treatments are being applied to mature, and intact, Picea mariana-Sphagnum spp. bog communities in their native habitat through the use of ten large (approximately 12 m wide, 10 m high) open-topped enclosures. We are tracking vegetation green-up and senescence in these chambers, at both the individual and whole-community level, using repeat digital photography. Within each chamber, digital camera images are recorded every 30 minutes and uploaded to the PhenoCam (http://phenocam.sr.unh.edu) project web page, where they are displayed in near-real-time. Image processing is conducted nightly to extract quantitative measures of canopy color, which we characterize using Gcc, the green chromatic coordinate. Data from a camera mounted outside the chambers (since November 2014) indicate strong seasonal variation in Gcc for both evergreen shrubs and trees. Shrub Gcc rises steeply in May and June, and declines steeply in September and October. By comparison, tree Gcc rises gradually from March through June, and declines gradually from

  15. Abundance and population structure of eastern worm snakes in forest stands with various levels of overstory tree retention

    Treesearch

    Zachary I. Felix; Yong Wang; Callie Jo Schweitzer

    2010-01-01

    In-depth analyses of a species’ response to canopy retention treatments can provide insight into reasons for observed changes in abundance. The eastern worm snake (Carphophis amoenus amoenus Say) is common in many eastern deciduous forests, yet little is known about the ecology of the species in managed forests. We examined the relationship between...

  16. Crustal and upper-mantle structure beneath eastern margin of Tibet from local and teleseismic traveltime data

    NASA Astrophysics Data System (ADS)

    Guo, B.; Liu, Q.; Chen, J.; van der Hilst, R. D.; Li, S.; Li, Y.

    2011-12-01

    The mechanism of Tibetan formation and evolution is debated, with rigid block extrusion, distributed thickening, injection of Indian crust into Tibetan lower crust, and channel flow. These competing models have been proposed for the uplift and deformation of Tibet, each with different implications for the eastern part of Tibet plateau. For investigating and verifying the dynamic model of eastern Tibet, during 2006 to 2009, Institute of Geology, CEA developed a dens seismic array in West Sichuan region, which have record many local and teleseismic events, including the great Wenchuan earthquake and the aftershocks. In this study, we determined the fast P-wave direction and three-dimensional P-wave velocity structure of crust and upper mantle down to 400km beneath the eastern Tibet margin area by simultaneously inverting local and teleseismic travel time data record by West Sichuan Seismic Array and local seismic network. Our data set is composed of over 85,000 P-wave arrival times from 4602 local and regional earthquakes and over 92,000 travel times from 2302 teleseismic events recorded by 472 seismic stations. We used a grid searching method to determined hypocenters of local events based on the traveltime field in 3-D velocity structure. Our tomography method is using Fast marching method for forward and LSQR method for inversion. The method also takes into account the variation of the Moho's depth. During the tomographic inversion, the Moho geometry is fixed and the velocities at the grid nodes anisotropic parameters at blocks in upper-mantle are determined. Our results show that: (1) the shallow velocity of surface is consistent correlates with the surface geological features, the Chuandian and Songpan-Ganzi block is imaged as high-velocity feature, and Sichuan basin imaged as low-velocity. (2) The middle-lower crustal velocities from 30 km to 50 km characterize a mechanically weak belts beneath Songpan-Ganzi and Chuandian blocks, but it is strong lateral

  17. The antineoplastic quassinoids of Simaba cuspidata spruce and Ailanthus grandis Prain.

    PubMed

    Polonsky, J; Varon, Z; Moretti, C; Pettit, G R; Herald, C L; Rideout, J A; Saha, S B; Khastgir, H N

    1980-01-01

    The South American Simaba cuspidata Spruce and North Indian Ailanthus grandis Prain were investigated as sources of potentially useful antineoplastic agents. Both of these Simaroubaceae plant species were found to produce 6 alpha-tigloyloxychaparrinone (4a) and the new quassinoid 6 alpha-tigloyloxychaparrin (3b). The latter structure was determined by interpretation of spectral data and oxidation to 6 alpha-tigloyloxychaparrinone (4a). While both glycol 3b and alpha-ketol 4a were found to significantly inhibit growth of the murine P388 lymphocytic leukemia cell line, only the alpha-ketol (4a) inhibited growth of the corresponding in vivo system.

  18. Structure and present-day compression in the offshore area between Alicante and Ibiza Island (Eastern Iberian Margin)

    NASA Astrophysics Data System (ADS)

    Maillard, Agnès; Mauffret, Alain

    2013-04-01

    This study deals with the structure and recent deformation of the Eastern Iberian margin, extending from basement to seafloor and including the south-western margin of the Valencia Basin, the Alicante Shelf, the Ibiza Channel and its southern margin descending into the Algerian Basin. This area underwent a complex tectonic evolution linked to the back-arc opening of the North-western Mediterranean and the concomitant contraction of the Betic belt due to the collision with blocks located between Africa and Europe. This Oligo-Miocene structural heritage gave rise to a complex and continuous deformation through times including Late Miocene post-orogenic extension and Pliocene to Quaternary compression in the western Balearic area and coeval extension in the Valencia basin. This study presents maps of the depth to basement and Base of the Pliocene, as well as bathymetry data and seismic lines, which provide a precise integrated 3D study of the offshore domain. It reveals a major reactivation of the area, represented by the N80 to N60 trending structures, small discontinuous folds and thrusts in the Ibiza Channel and a large flexure on the Alicante shelf. The structures are picked out by erosion surfaces or deposits linked to the Messinian Salinity Crisis (MSC). These markers are ubiquitous in the seismic sedimentary sequences and record the lateral and vertical deformation active from the Messinian Salinity Crisis to the Present. The contraction in the western Iberian margin and concomitant extension in the southern Valencia Basin are consistent with the regional stress field as determined from the focal mechanisms of offshore earthquakes or recent GPS measurements. The tectonic compression of the studied area casts doubt on the eventual propagation of the present-day compressive stress from the Algerian margin to the Western Balearic Promontory.

  19. Structure of the Maláguide Complex near Vélez Rubio (Eastern Betic Cordillera, SE Spain)

    NASA Astrophysics Data System (ADS)

    FernáNdez-FernáNdez, E. M.; Jabaloy-SáNchez, A.; Nieto, F.; GonzáLez-Lodeiro, F.

    2007-08-01

    The Maláguide Complex of the Betic Cordillera represents a tectonic element which mostly underwent brittle deformation during the Alpine orogeny, and that covers the high-pressure/low-temperature (HP/LT) complexes of the internal Betic Cordillera. The evolution of this complex can help to determine both when the lower HP/LT complexes began to exhume and the behavior of the upper plate during this process. Moreover, this complex is a key element to understanding the relationships between the late orogenic extension in the internal Betic Cordillera and the coeval compression in the External Zones of the same mountain chain. This paper focuses in the geometry and kinematics of the Alpine structures of this Maláguide Complex in the eastern Betic Cordillera, near the village of Vélez Rubio. We propose that these Alpine structures can be grouped into three main stages. First stage (Paleogene) began with a synmetamorphic slaty cleavage produced in anchizone conditions. This foliation is associated with northward vergent structures and was probably connected with the superposition of the Maláguide Complex over the Alpujárride during the middle Eocene. This first stage ended with the thinning of the Maláguide Complex (Oligocene) by an extensional detachment with a top-to-the-NNW sense of movement. Second stage records the convergence of the External and Internal Zones during the Aquitanian-Burdigalian. This convergence was a right-lateral transpression that produced back thrusts and extensional structures that exhumed the HP/LT rocks of the Alpujárride Complex. Third stage corresponds to the evolution from the late Burdigalian to the present-day, when the Internal and External zones were welded together.

  20. An unusual triangle structure associated with thrust front development in the thin-skinned Eastern Jura Mountains

    NASA Astrophysics Data System (ADS)

    Malz, Alexander; Madritsch, Herfried; Meier, Beat; Heuberger, Stefan; Kley, Jonas

    2014-05-01

    The Late Miocene to Early Pliocene Jura fold-and-thrust belt, stretching across northern Switzerland and eastern France, is a classical example of a thin-skinned foreland fold-and-thrust belt, its basal décollement being located in Mid- to Upper Triassic evaporites. The arcuate mountain range referred to as the Folded Jura is formed by mainly N-vergent thrusts and associated folds. In our study area, comprising the easternmost part of the thrust belt, the border between the Folded Jura and the non-detached autochthonous foreland (Tabular Jura) is not clearly defined. In most interpretations, the frontal thrust is taken to coincide with the northernmost anticline of the Folded Jura visible at the surface. Newly reprocessed, depth-migrated reflection seismic sections allow us to closer analyse the regional structural framework of the thrust front. Constant line-length and area cross section balancing techniques are applied to verify geometry of the interpreted structures. The best matching interpretation of the thin-skinned thrust belt front is a complex triangle structure, which traces an offset of the basal décollement by an inherited pre-exisiting normal fault that was previously associated with the border fault of a Late Paleozoic trough. This "unusual" triangle structure is defined by a number of (at least two) thrusts and backthrusts above each other associated with several secondary faults. The most characteristic feature of the fault zone is its low width with respect to the stratigraphic thickness influenced by the fault. The triangle structure shows a very uniform amount of shortening over much of its length. We interpret this uniform shortening to suggest that the configuration of the structure represents a maximum attainable, "saturated" amount of deformation achieved during an initial phase of Jura folding. To the west of our study area the triangle structure merges with the northernmost Jura anticline, which shows a conspicuous change in strike from

  1. An Expanded Chesapeake Bay Impact Structure, Eastern Virginia: New Corehole and Geophysical Data

    NASA Technical Reports Server (NTRS)

    Powars, D. S.; Johnson, G. H.; Edwards, L. E.; Horton, J. W., Jr.; Gohn, G. S.; Catchings, R. D.; McFarland, E. R.; Izett, G. A.; Bruce, T. S.; Levine, J. S.

    2002-01-01

    Data from several deep coreholes, seismic reflection surveys, and surface mapping indicate that the buried Chesapeake Bay impact structure is wider (160 km, due to 35-km-wide outer fracture zone) and deeper (2 miles) than previously reported. Additional information is contained in the original extended abstract.

  2. Biological structure and dynamics of littoral fish assemblages in the eastern Finger Lakes

    USGS Publications Warehouse

    McKenna, James E.

    2001-01-01

    Fish assemblages from three of the New York Finger Lakes were examined for structure within and between lakes and over time. Species-area relationships indicated that local fish assemblages are the result of recent, lake-specific events that altered the regional species pool. Fish assemblages varied among seasons and those occupying eutrophic waters had different characteristics from those in oligotrophic waters. Bluntnose minnows (Pimephales notatus) were a persistent and important component of most assemblages, but abundance of bluegill (Lepomis macrochirus) was the most distinguishing feature. Species associations indicated that interactions among the fishes had little influence on assemblage structure. Correlations between community structure and abiotic factors were identified. Ten abiotic variables were strongly associated with the species assemblages, but could not fully explain differences between assemblages. Results indicate that the abundance and diversity of water column feeders was related to productivity of lake habitat. In general, fish populations were smaller in oligotrophic waters and water column feeders were poorly represented in those assemblages. Productivity at various trophic levels was implicated as a major factor determining lake fish assemblage structure.

  3. Transverse zones controlling the structural evolution of the Zipaquira Anticline (Eastern Cordillera, Colombia): Regional implications

    NASA Astrophysics Data System (ADS)

    García, Helbert; Jiménez, Giovanny

    2016-08-01

    We report paleomagnetic, magnetic fabric and structural results from 21 sites collected in Cretaceous marine mudstones and Paleogene continental sandstones from the limbs, hinge and transverse zones of the Zipaquira Anticline (ZA). The ZA is an asymmetrical fold with one limb completely overturned by processes like gravity and salt tectonics, and marked by several axis curvatures. The ZA is controlled by at least two (2) transverse zones known as the Neusa and Zipaquira Transverse Zones (NTZ and ZTZ, respectively). Magnetic mineralogy methods were applied at different sites and the main carriers of the magnetic properties are paramagnetic components with some sites being controlled by hematite and magnetite. Magnetic fabric analysis shows rigid-body rotation for the back-limb in the ZA, while the forelimb is subjected to internal deformation. Structural and paleomagnetic data shows the influence of the NTZ and ZTZ in the evolution of the different structures like the ZA and the Zipaquira, Carupa, Rio Guandoque, Las Margaritas and Neusa faults, controlling several factors as vergence, extension, fold axis curvature and stratigraphic detatchment. Clockwise rotations unraveled a block segmentation following a discontinuos model caused by transverse zones and one site reported a counter clockwise rotation associated with a left-lateral strike slip component for transverse faults (e.g. the Neusa Fault). We propose that diverse transverse zones have been active since Paleogene times, playing an important role in the tectonic evolution of the Cundinamarca sub-basin and controlling the structural evolution of folds and faults with block segmentation and rotations.

  4. Litho-structural analysis of eastern part of Ilesha schist belt, Southwestern Nigeria

    NASA Astrophysics Data System (ADS)

    Fagbohun, Babatunde Joseph; Adeoti, Blessing; Aladejana, Olabanji Odunayo

    2017-09-01

    The Ilesha schist belt is an excellent example of high strain shear belt within basement complex of southwestern Nigeria which is part of the larger West African Shield. The Ilesha schist belt is characterised by metasediment-metavolcanic, migmatite-gneiss and older granite rocks and the occurrence of a Shear zone which has been traced to and correlated with the central Hoggar Neoproterozoic shear zone as part of the Trans-Saharan Belt. Although the area is interesting in terms of geologic-tectonic setting, however, detailed geological assessment and structural interpretation of features in this area is lacking due accessibility problem. For these reasons we applied principal component analysis (PCA) and band ratio (BR) techniques on Landsat 8 OLI data for lithological discrimination while for structural interpretation, filtering techniques of edge enhancement and edge detection was applied on digital elevation model (DEM) acquired by shuttle radar topographic mission (SRTM) sensor. The PCA outperform BR for discrimination between quartzite and granite which are the most exposed rock units in the area. For structural interpretation, DEM was used to generate shaded relief model and edge maps which enable detailed structural interpretation. Geologic fieldwork was further conducted to validate structures and units identified from image processing. Based image interpretation, three deformation events were identified. The first event (D1) which is majorly a ductile deformation produced foliations and folds whose axial planes trend in NNE-SSW. The second event (D2) resulted in reactivation and rotation of the D1 structures particularly the folds in the NE-SW. The third event (D3) produced a transgressive deformation starting with the ductile deformation resulting in the development of sigmoidal structures oriented in NE-SW to E-W direction and the brittle deformation occurring at later stages producing fractures oriented in the E-W to NE-SW directions. These results have

  5. 3D P-wave Velocity Structure Beneath the Eastern Canadian Shield and Northern Appalachian Region

    NASA Astrophysics Data System (ADS)

    Villemaire, M.; Darbyshire, F. A.; Bastow, I. D.

    2010-12-01

    Previous seismic studies of the upper mantle of the Canadian Shield have indicated some low-velocity anomalies within the cratonic lithosphere in the Abitibi-Grenville region. The lack of seismograph station coverage to the east and south-east of the studied area prevented definition of the 3D geometry of these anomalies. Adding new stations from the province of Quebec and from the northeastern United States allows us to carry out new studies of the P-wave velocity structure of the upper mantle, in order to better understand the complexity of the region and the interaction of the lithosphere with possible thermal anomalies in the underlying mantle. We analysed teleseismic P wave arrivals from almost 200 earthquakes, recorded at 45 stations deployed across the provinces of Quebec and Ontario and across the northeastern US. The relative arrival times of teleseismic P waves across the array were measured using the cross-correlation method of VanDecar & Crosson (1990). The travel time data were then inverted to estimate the 3D P-wave velocity structure beneath the region, using the least-squares tomographic inversion code of VanDecar (1991). The model shows some interesting features. We see a diffuse low-velocity structure beneath New-England that extends to at least 500 km depth, and that may be related to the Appalachian Mountain belt. There is also a linear low-velocity structure, flanked by higher velocities, perpendicular to the Grenville Front, and along the Ottawa Valley. We interpret this feature as a mantle signature of the Great Meteor Hotspot track. We have looked for systematic differences between the mantle underlying the Archean Superior craton and the Proterozoic Grenville Province but did not find a significant difference in the upper mantle. We investigate the role of thermal and compositional effects to interpret the velocity models and to relate the patterns of the anomalies to past and present tectonic structures.

  6. Possible red spruce decline: Contributions of tree-ring analysis

    SciTech Connect

    Van Deusen, P.C. ); Reams, G.A. ); Cook, E.R. )

    1991-01-01

    Debate continues about the cause of apparent unprecedented decreases in ring width at all elevations, and increasing levels of mortality at high elevations, in red spruce (Picea rubens) stands in the northeastern United States. These growth and mortality trends are often used as evidence of red spruce decline, but the possibility remains that they may be occurring naturally. Two hypotheses are being used to explain the causes of red spruce growth reduction across its range and increased levels of standing dead at some high-elevation sites. This article summarizes the basic evidence used by advocates of these hypotheses and discusses the strengths of their arguments. The information presented is based primarily on tree-ring studies sponsored by the Forest Response Program, which is part of the National Acid Precipitation Assessment Program.

  7. Response of Lutz, Sitka, and white spruce to attack by Dendroctonus rufipennis (Coleoptera: Scolytidae) and blue stain fungi

    Treesearch

    Richard A. Werner; Barbara L. Illman

    1994-01-01

    Mechanical wounding and wounding plus inoculation with a blue-stain fungus, Leptographium abietinum (Peck), associated with the spruce beetle, Dendroctonus rufipennis (Kirby), caused an induced reaction zone or lesion around the wound sites in Lutz spruce, Picea lutzii Little, Sitka spruce, P. sitchensis (Bong.) Carr., and white spruce, P. glauca (Moench) Voss, in...

  8. Structure and dynamics in the north Jizhong Depression, Bohai Bay Basin, Eastern China

    NASA Astrophysics Data System (ADS)

    Miao, Q.; Qi, J.; Zhang, J.

    2015-12-01

    Study of structural geology in the north Jizhong Depression, Bohai Bay has achieved great breakthroughs in recent years. However the studies of structure and dynamics still remain much controversy. Based on the 3D and partial 2D seismic data, combined with regional geology and well data, the characteristics of structures in the north Jizhong Deprssion are analyzed, the dynamics is discussed. Our analyses show that the Cenozoic structures in the north Jizhong Depression can be subdivided into extensional system and strike-slip system. Extensional system concludes series of normal faults and transfer faults. Normal faults are mainly trend NNE and NE. They control the Paleogene sediments in sub-depressions of hanging-wall, and bottom out into a sub-horizontal detachment zone in deep level shaped like listric. Transfer faults mainly adjust displacement of normal faults, yet some like Tongbozhen and Niutuozhen are transfer faults in Paleocene and Eocene but change to normal faults in Oligocene. Strike-slip system is predominantly consisted by sub-vertical right-lateral strike-slip faults such as Xin`anzhen and Maxi. From seismic profiles, Xin`anzhen and Maxi cut into basement but only influence the sediments of Ed of Paleogene and Lower Neogene. Based on the relation of sedimentary sequence and faults, the extensional system mainly develops from Paleocene to Late Oligocene, but strike-slip system predominantly develops from Late Oligocene to Miocene. From the superposed section of crustal structure and basin structure in Jizhong Depression, the Cenozoic sub-basin is just located on the thinner zones of crustal, corresponding with the location of mantle uplift. It indicates that the Paleogene development of Jizhong Depression is related to the horizontal tension caused by uplift of magma in mantle. The results illustrate that extensional deformation in Jizhong depression is caused by the uplift of magma. The right-lateral strike-slip deformation, same with Tancheng

  9. Excess growing-season water limits lowland black spruce productivity

    NASA Astrophysics Data System (ADS)

    Dymond, S.; Kolka, R. K.; Bolstad, P. V.; Gill, K.; Curzon, M.; D'Amato, A. W.

    2015-12-01

    The annual growth of many tree species is limited by water availability, with growth increasing as water becomes less scarce. In lowland bogs of northern Minnesota, however, black spruce (Picea mariana) is often exposed to excess water via high water table elevations. These trees grow in thick deposits of organic mucky peat and often have shallow rooting systems to avoid the complete submersion of roots in water. While it is generally believed that black spruce decrease growth rates with rising water table elevations, this hypothesis has not been tested in situ. We used a unique, 50-year record of daily bog water table elevations at the Marcell Experimental Forest (MEF) in northern Minnesota to investigate the relationship between climate and black spruce productivity. Nine 1/20th ha circular plots were established in five different bogs and tree height, diameter-at-breast-height (DBH), and crown class were recorded. Additionally, two perpendicular cores were collected on all trees greater than 10 cm diameter-at-breast-height. Tree cores were sanded, mounted, cross-dated, and de-trended according to standard dendrochronological procedures. Ring width measurements were correlated with precipitation, temperature, and water table elevation using package BootRes in R to determine the climatic variables most associated with stand level productivity. Across the different plots, we found that early growing season water table elevation (May and June) was negatively correlated with both individual and stand-level black spruce growth (p < 0.01), while growth was positively correlated with March temperatures (p < 0.01). No significant relationships existed between black spruce growth and monthly precipitation. If summer water table elevations in these peatland ecosystems rise as is anticipated with more extreme precipitation events due to climate change, we could see an overall decrease in the stand level productivity of black spruce.