| a comparative toxicity assessment of materials used in aquatic construction. | comparative toxicity testing was performed on selected materials that may be used in aquatic construction projects. the tests were conducted on the following materials: (1) untreated wood species (hemlock [tsuga ssp], western red cedar (thuja plicata), red oak [quercus rubra], douglas fir [pseudotsuga menziesii], red pine [pinus resinosa], and tamarack [larix ssp]); (2) plastic wood; (3) ecothermo wood hemlock stakes treated with preservatives (e.g., chromated copper arsenate [cca], creosote, al ... | 2011 | 21222116 |
| the isolation, characterization and effect of lignin isolated from steam pretreated douglas-fir on the enzymatic hydrolysis of cellulose. | douglas-fir was so(2)-steam pretreated at different severities (190, 200, and 210°c) to assess the possible negative effect of the residual and isolated lignins on the enzymatic hydrolysis of the steam pretreated substrates. when various isolated lignins were added to the avicel hydrolysis reactions, the decrease in glucose yields ranged from 15.2% to 29.0% after 72 h. it was apparent that the better hydrolysis yields obtained at higher pretreatment severities were more a result of the greater a ... | 2010 | 21256740 |
| ectomycorrhizal hyphae structure components of the soil bacterial community for decreased phosphatase production. | ectomycorrhizal fungi (emf) provide nutrients to their hosts by means of hyphae that extend beyond nutrient-depleted rhizosphere soil. soil bacteria may compete with emf for nutrients or may act synergistically to enhance nutrient supply to hosts. to assess the interactions between hyphae and bacteria, two types of small, sand-filled mesh bags were incubated in a pseudotsuga menziesii/betula papyrifera forest. the bags allowed ingrowth by emf (35-µm mesh) or excluded hyphae (0.5-µm mesh), while ... | 2011 | 21265870 |
| climate-related trends in sapwood biophysical properties in two conifers: avoidance of hydraulic dysfunction through coordinated adjustments in xylem efficiency, safety and capacitance. | in the pacific north-west, the cascade mountain range blocks much of the precipitation and maritime influence of the pacific ocean, resulting in distinct climates east and west of the mountains. the current study aimed to investigate relationships between water storage and transport properties in populations of douglas-fir (pseudotsuga menziesii) and ponderosa pine (pinus ponderosa) adapted to both climates. sapwood thickness, capacitance, vulnerability to embolism, and axial and radial conducti ... | 2011 | 21309793 |
| cellulose accessibility limits the effectiveness of minimum cellulase loading on the efficient hydrolysis of pretreated lignocellulosic substrates. | a range of lignocellulosic feedstocks (including agricultural, softwood and hardwood substrates) were pretreated with either sulfur dioxide-catalyzed steam or an ethanol organosolv procedure to try to establish a reliable assessment of the factors governing the minimum protein loading that could be used to achieve efficient hydrolysis. a statistical design approach was first used to define what might constitute the minimum protein loading (cellulases and ß-glucosidase) that could be used to achi ... | 2011 | 21310050 |
| vertical and seasonal variation in the {delta}13c of leaf-respired co2 in a mixed conifer forest. | the c-isotopic composition (δ(13)c) of leaf respiration (δ(lr)) has previously been shown to vary among functional groups, plant organs and times of day. we here investigated vertical and seasonal variation in δ(lr) through deep (∼35 m) forest canopies. we measured δ(lr), δ(13)c of leaf bulk organic matter (δ(lb)), specific leaf area, net photosynthesis (a) and dark respiration in shade, middle and sun foliage in four conifer species from may to august. we used keeling plots to estimate δ(lr); w ... | 2011 | 21551356 |
| estimation of canopy average mesophyll conductance using δ(13) c of phloem contents. | conductance to co(2) inside leaves, known as mesophyll conductance (g(m) ), imposes large limitations on photosynthesis. because g(m) is difficult to quantify, it is often neglected in calculations of (13) c photosynthetic discrimination. the "soluble sugars method" estimates g(m) via differences between observed photosynthetic discrimination, calculated from the δ(13) c of soluble sugars, and discrimination when g(m) is infinite. we expand upon this approach and calculate a photosynthesis-weigh ... | 2011 | 21554329 |
| assessment of uncertainty in functional-structural plant models. | background and aims constructing functional-structural plant models (fspms) is a valuable method for examining how physiology and morphology interact in determining plant processes. however, such models always have uncertainty concerned with whether model components have been selected and represented effectively, with the number of model outputs simulated and with the quality of data used in assessment. we provide a procedure for defining uncertainty of an fspm and how this uncertainty can be re ... | 2011 | 21593061 |
| multiple resonance damping or how do trees escape dangerously large oscillations? | to further understand the mechanics of trees under dynamic loads, we recorded damped oscillations of a douglas fir (pseudotsuga menziesii) tree and of its stem without branches. eigenfrequencies of the branches were calculated and compared to the oscillation frequency of the intact tree. the term eigenfrequency is used here to characterize the calculated resonance frequency of a branch fixed at the proximal end to a solid support. all large branches had nearly the same frequency as the tree. thi ... | 2007 | 21636359 |
| the ecology of tick-transmitted infections in the redwood chipmunk (tamias ochrogenys). | the redwood chipmunk contributes to the maintenance of tick-borne diseases in northern california. the range of redwood chipmunks overlaps that of western black-legged ticks and tick-borne disease, including granulocytic anaplasmosis and lyme borreliosis. chipmunks have high anaplasma phagocytophilum pcr- and seroprevalence, are infested with a diversity of ixodes spp. ticks, and are reservoir competent for borrelia burgdorferi. we hypothesized that chipmunks could maintain tick-borne disease on ... | 2011 | 21643481 |
| female parthenogenetic apomixis and androsporogenesis in douglas-fir embryonal initials in an artificial sporangium. | control of female parthenogenetic apomixis and androsporogenesis of douglas-fir embryonal initials was studied using an experimental culture system in which changes in growth condition can mediate changes in cell identity and outcomes. this culture system constitutes an artificial sporangium in which myriad culture conditions can be simulated and should be applicable for research on a variety of gymnosperms. in this study, embryonal initials from developing seeds from two douglas-fir trees were ... | 2011 | 21644002 |
| climate determines upper, but not lower, altitudinal range limits of pacific northwest conifers. | does climate determine species' ranges? rapid rates of anthropogenic warming make this classic ecological question especially relevant. we ask whether climate controls range limits by quantifying relationships between climatic variables (precipitation, temperature) and tree growth across the altitudinal ranges of six pacific northwestern conifers on mt. rainier, washington, usa. results for three species (abies amabilis, callitropsis nootkatensis, tsuga mertensiana) whose upper limits occur at t ... | 2011 | 21797160 |
| genotypic variation among douglas-fir tussock moth nucleopolyhedrovirus (opnpv) isolates in the western united states. | periodic outbreaks of the douglas-fir tussock moth (orgyia pseudotsugata) in forests of western north america generally end with a sudden collapse due primarily to an epizootic caused by a nucleopolyhedrovirus (npv) that occurs naturally within o. pseudotsugata populations. we genotypically characterized npv populations from washington state, oregon, idaho, new mexico and california for the first time. of 159 infected tussock moth samples, restriction fragment length polymorphism (rflp) analysis ... | 2011 | 21684287 |
| mycorrhizal networks affect ectomycorrhizal fungal community similarity between conspecific trees and seedlings. | ectomycorrhizal (em) networks (mn) are thought to be an important mode of em fungal colonization of coniferous seedlings. how mns affect em communities on seedlings, and how this varies with biotic and abiotic factors, is integral to understanding their importance in seedling establishment. we examined em fungal community similarity between mature trees and conspecific interior douglas-fir (pseudotsuga menziesii var. glauca) seedlings in two experiments where seed and nursery-grown seedlings ori ... | 2011 | 21822679 |
| bordered pit structure and function determine spatial patterns of air-seeding thresholds in xylem of douglas-fir (pseudotsuga menziesii; pinaceae) trees. | the air-seeding hypothesis predicts that xylem embolism resistance is linked directly to bordered pit functioning. we tested this prediction in trunks, roots, and branches at different vertical and radial locations in young and old trees of pseudotsuga menziesii. dimensions of bordered pits were measured from light and scanning electron micrographs, and physiological data were from published values. consistent with observations, calculations showed that earlywood tracheids were more resistant to ... | 2006 | 21642104 |
| do gymnosperm needles pull water through the xylem produced in the same year as the needle? | this research investigated the longevity of functional connections between leaf traces and stem xylem in 16 species of conifers to better understand the spatial use of sapwood for water transport. the first question was which ring(s) stained when a vacuum was applied to the distal end of the cut surface of a needle attached to a short stem segment. the vacuum was applied to either 1- or 2-yr-old foliage taken from 4-6-yr-old saplings. the 16 species were then categorized based on the growth ring ... | 2005 | 21652392 |
| density-independent high moisture content measurement using phase shifts at two microwave frequencies. | density-independent high moisture content measurement is required in actual production line. in this paper, the experimental results for high moisture content measurement using microwave free-space technique are presented. the method is based on a ratio of phase shifts at two microwave frequencies after propagating through a sample. the experiments were performed with three kinds of sawdust named momizai, cedar and douglas fir. in the high moisture content above 130%, the root mean square error ... | 2010 | 21721335 |
| water stress, shoot growth and storage of non-structural carbohydrates along a tree height gradient in a tall conifer. | we analysed concentrations of starch, sucrose, glucose and fructose in upper branch wood, foliage and trunk sapwood of douglas-fir trees in height classes ranging from ôê+2 to ôê+57ôçâm. mean concentrations of non-structural carbohydrates (nsc) for all tissues were highest in the tallest height class and lowest in the lowest height class, and height-related trends in nsc were most pronounced in branches. throughout a 17-month sampling period, mean values of branch nsc from the 57ôçâm trees range ... | 2011 | 21722142 |
| evaluation of hemicellulose removal by xylanase and delignification on shf and ssf for bioethanol production with steam-pretreated substrates. | steam-pretreated sweet sorghum bagasse (ssb) and douglas-fir (df) were employed for shf and ssf to evaluate the effects of xylanase supplementation and delignification on ethanol production. results indicated final ethanol concentration in shf could reach 28.4g/l (ssb) and 20.4g/l (df) by xylanase supplementation with the increase of 46% and 61% in comparison with controls. the delignification could significantly enhance final ethanol concentration to 31.2g/l (ssb) and 30.2g/l (df) with the incr ... | 2011 | 21816609 |
| role of relative humidity in colony founding and queen survivorship in two carpenter ant species. | conditions necessary for optimal colony foundation in two carpenter ant species, camponotus modoc wheeler and camponotus vicinus mayr, were studied. camponotus modoc and c. vicinus queens were placed in douglas-fir, pseudotsuga menziesii (mirb. franco) and styrofoam blocks conditioned in sealed chambers at 70, 80, or 100% rh. nanitic workers produced after 12 wk were used to assess the effects of substrate and moisture content on colony initiation. queens of c. vicinus in douglas-fir and styrofo ... | 2011 | 21735888 |
| sea sand disruption method (ssdm) as a valuable tool for isolating essential oil components from conifers. | essential oils are one of nature's most precious gifts with surprisingly potent and outstanding properties. coniferous oils, for instance, are nowadays being used extensively to treat or prevent many types of infections, modify immune responses, soothe inflammations, stabilize moods, and to help ease all forms of non-acute pain. given the broad spectrum of usage of coniferous essential oils, a fast, safe, simple, and efficient sample-preparation method is needed in the estimation procedure of es ... | 2011 | 22083917 |
| Metal stress and decreased tree growth in response to biosolids application in greenhouse seedlings and in situ Douglas-fir stands. | To assess physiological impacts of biosolids on trees, metal contaminants and phytochelatins were measured in Douglas-fir stands amended with biosolids in 1982. A subsequent greenhouse study compared these same soils to soils amended with fresh wastewater treatment plant biosolids. Biosolids-amended field soils had significantly higher organic matter, lower pH, and elevated metals even after 25 years. In the field study, no beneficial growth effects were detected in biosolids-amended stands and ... | 2012 | 22035937 |
| accounting for density reduction and structural loss in standing dead trees: implications for forest biomass and carbon stock estimates in the united states. | abstract: background: standing dead trees are one component of forest ecosystem dead wood carbon (c) pools, whose national stock is estimated by the u.s. as required by the united nations framework convention on climate change. historically, standing dead tree c has been estimated as a function of live tree growing stock volume in the u.s.'s national greenhouse gas inventory. initiated in 1998, the usda forest service's forest inventory and analysis program (responsible for compiling the nation ... | 2011 | 22115425 |
| fire history and tree recruitment in the colorado front range upper montane zone: implications for forest restoration. | forests experiencing moderate- or mixed-severity fire regimes are presumed to be widespread across the western united states, but few studies have characterized these complex disturbance regimes and their effects on contemporary forest structure. restoration of pre-fire-suppression open-forest structure to reduce the risk of uncharacteristic stand-replacing fires is a guiding principle in forest management policy, but identifying which forests are clear candidates for restoration remains a chall ... | 2011 | 21939055 |
| the heterogeneous levels of linkage disequilibrium in white spruce genes and comparative analysis with other conifers. | in plants, knowledge about linkage disequilibrium (ld) is relevant for the design of efficient single-nucleotide polymorphism arrays in relation to their use in population and association genomics studies. previous studies of conifer genes have shown ld to decay rapidly within gene limits, but exceptions have been reported. to evaluate the extent of heterogeneity of ld among conifer genes and its potential causes, we examined ld in 105 genes of white spruce (picea glauca) by sequencing a panel o ... | 2011 | 21897435 |
| The lignin present in steam pretreated softwood binds enzymes and limits cellulose accessibility. | The influence of cellulose accessibility and protein loading on the efficiency of enzymatic hydrolysis of steam pretreated Douglas-fir was assessed. It was apparent that the lignin component significantly influences the swelling/accessibility of cellulose as at low protein loadings (5FPU/g cellulose), only 16% of the cellulose present in the steam pretreated softwood was hydrolyzed while almost complete hydrolysis was achieved with the delignified substrate. When lignin (isolated from steam pret ... | 2012 | 22047660 |
| biogeochemistry of a temperate forest nitrogen gradient. | wide natural gradients of soil nitrogen (n) can be used to examine fundamental relationships between plant-soil-microbial n cycling and hydrologic n loss, and to test n-saturation theory as a general framework for understanding ecosystem n dynamics. we characterized plant production, n uptake and return in litterfall, soil gross and net n mineralization rates, and hydrologic n losses of nine douglas-fir (pseudotsuga menziesii) forests across a wide soil n gradient in the oregon coast range (u.s. ... | 2011 | 21870622 |
| orientation behavior of the predator laricobius nigrinus (coleoptera: derodontidae) to hemlock woolly adelgid and host tree odors in a multi-chambered olfactometer. | we studied the adult ambulatory response of the predator, laricobius nigrinus fender (coleoptera: derodontidae), to odors from its prey, adelges tsugae annand, the hemlock woolly adelgid, and foliage of hemlock woolly adelgid, host hemlocks (tsuga spp.), and other conifers. both the predator and hemlock woolly adelgid are apparently native to western north america, but the predator is being released in the eastern united states, which has different hemlock species, for biological control of a l ... | 2011 | 22251687 |
| do mycorrhizal network benefits to survival and growth of interior douglas-fir seedlings increase with soil moisture stress? | facilitation of tree establishment by ectomycorrhizal (em) networks (mns) may become increasingly important as drought stress increases with climate change in some forested regions of north america. the objective of this study was to determine (1) whether temperature, co(2) concentration ([co(2)]), soil moisture, and mns interact to affect plant establishment success, such that mns facilitate establishment when plants are the most water stressed, and (2) whether transfer of c and water between p ... | 2011 | 22393502 |
| pseudomonas fluorescens bbc6r8 type iii secretion mutants no longer promote ectomycorrhizal symbiosis. | the mycorrhiza helper bacterium (mhb) pseudomonas fluorescens bbc6r8 promotes the ectomycorrhizal symbiosis between douglas fir roots and laccaria bicolor. in this study, we identified a non-flagellar type iii secretion system (t3ss) in the draft genome of bbc6r8 similar to that described in the biocontrol strain p. fluorescens sbw25. we examined whether this t3ss plays a role in the bbc6r8 mycorrhizal helper effect by creating a deletion in the rscrst genes encoding the central channel of the i ... | 2011 | 23761252 |
| soil microbe active community composition and capability of responding to litter addition after 12 years of no inputs. | one explanation given for the high microbial diversity found in soils is that they contain a large inactive biomass that is able to persist in soils for long periods of time. this persistent microbial fraction may help to buffer the functionality of the soil community during times of low nutrients by providing a reservoir of specialized functions that can be reactivated when conditions improve. a study was designed to test the hypothesis: in soils lacking fresh root or detrital inputs, microbial ... | 2012 | 23263952 |
| ectomycorrhizal fungal community assembly on regenerating douglas-fir after wildfire and clearcut harvesting. | wildfire severity in forests is projected to increase with warming and drying conditions associated with climate change. our objective was to determine the impact of wildfire and clearcutting severity on the ectomycorrhizal fungal (emf) community of douglas-fir seedlings in the dry forests of interior british columbia, canada. we located our study within and surrounding the area of the mclure fire (august 2003). we hypothesized that disturbance would affect emf community assembly due to reductio ... | 2012 | 23263530 |
| a snp resource for douglas-fir: de novo transcriptome assembly and snp detection and validation. | douglas-fir (pseudotsuga menziesii), one of the most economically and ecologically important tree species in the world, also has one of the largest tree breeding programs. although the coastal and interior varieties of douglas-fir (vars. menziesii and glauca) are native to north america, the coastal variety is also widely planted for timber production in europe, new zealand, australia, and chile. our main goal was to develop a snp resource large enough to facilitate genomic selection in douglas- ... | 2013 | 23445355 |
| belowground legacies of pinus contorta invasion and removal result in multiple mechanisms of invasional meltdown. | plant invasions can change soil biota and nutrients in ways that drive subsequent plant communities, particularly when co-invading with belowground mutualists such as ectomycorrhizal fungi. these effects can persist following removal of the invasive plant and, combined with effects of removal per se, influence subsequent plant communities and ecosystem functioning. we used field observations and a soil bioassay with multiple plant species to determine the belowground effects and post-removal leg ... | 2014 | 25228312 |
| transient gene expression of microprojectile-introduced dna in douglas-fir cotyledons. | plasmid dna containing the reporter gene uida encoding β-glucuronidase (gus), driven by the cauliflower mosaic virus 35s promoter, was introduced on high-velocity microprojectiles into cultured cotyledons of douglas-fir [pseudotsuga menziesii (mirb.) franco]. transient gene expression was measured by counting the number of distinct loci of gus activity per cotyledon. contrary to published results on angiosperms, repeated bombardments did not increase expression in douglas-fir. expression varied ... | 1991 | 24221286 |
| phosphite shifts physiological and hormonal profile of monterey pine and delays fusarium circinatum progression. | fusarium circinatum is the causal agent of pitch canker disease affecting pinus spp. and pseudotsuga menziesii worldwide. under strict quarantine measures, alternative approaches for disease control are necessary. phosphite (phi) salts are known for their fungicidal activity and as plant resistance elicitors; however, its potential is yet to be acknowledged in the pinus-f. circinatum model. the main aim of this study was to assess whether the application of a phi-based commercial formulation wou ... | 2017 | 28284060 |
| plants promote mating and dispersal of the human pathogenic fungus cryptococcus. | infections due to cryptococcus are a leading cause of fungal infections worldwide and are acquired as a result of environmental exposure to desiccated yeast or spores. the ability of cryptococcus to grow, mate, and produce infectious propagules in association with plants is important for the maintenance of the genetic diversity and virulence factors important for infection of animals and humans. in the western united states and canada, cryptococcus has been associated with conifers and tree spec ... | 2017 | 28212396 |
| characterization of condensed tannins and carbohydrates in hot water bark extracts of european softwood species. | condensed tannins extracted from european softwood bark are recognized as alternatives to synthetic phenolics. the extraction is generally performed in hot water, leading to simultaneous extraction of other bark constituents such as carbohydrates, phenolic monomers and salts. characterization of the extract's composition and identification of the extracted tannins' molecular structure are needed to better identify potential applications. bark from silver fir (abies alba [mill.]), european larch ... | 2015 | 26547588 |
| comparison of δ(18)o and δ(13)c values between tree-ring whole wood and cellulose in five species growing under two different site conditions. | we investigated the applicability of tree-ring whole-wood material for δ(18)o and δ(13)c analysis in comparison with the more time- and resource-intensive use of cellulose, by considering possible variability between (i) five different tree species (fagus sylvatica, quercus robur, picea abies, abies alba, pseudotsuga menziesii), (ii) two sites that differ in soil moisture, and (iii) climate conditions within a 10-year period. | 2015 | 26522315 |
| mapped dna probes from loblolly pine can be used for restriction fragment length polymorphism mapping in other conifers. | a high-density genetic map based on restriction fragment length polymorphisms (rflps) is being constructed for loblolly pine (pinus taeda l.). consequently, a large number of dna probes from loblolly pine are potentially available for use in other species. we have used some of these dna probes to detect rflps in 12 conifers and an angiosperm. thirty complementary dna and two genomic dna probes from loblolly pine were hybridized to southern blots containing dna from five species of pinus (p. elli ... | 1994 | 24186006 |
| an extractive removal step optimized for a high-throughput α-cellulose extraction method for δ13c and δ18o stable isotope ratio analysis in conifer tree rings. | stable isotope ratios (δ(13)c and δ(18)o) of tree-ring α-cellulose are important tools in paleoclimatology, ecology, plant physiology and genetics. the multiple sample isolation system for solids (msiss) was a major advance in the tree-ring α-cellulose extraction methods, offering greater throughput and reduced labor input compared to traditional alternatives. however, the usability of the method for resinous conifer species may be limited by the need to remove extractives from some conifer spec ... | 2016 | 27672185 |
| the population biology of bromus tectorum in forests: distinguishing the opportunity for dispersal from environmental restriction. | with increasing elevation and corresponding changes in the macroclimate, forest zones in the intermountain region of western north america are often dominated in turn by pinus ponderosa, pseudotsuga menziesii, abies grandis, an thuja plicata. bromus tectorum (cheatgrass), and introduced annual grass now abundant in the region's steppe, is uncommon in mature stands representative of these forest zones. in order to determine whether b. tectorum is largely excluded from these forests by insufficien ... | 1990 | 28312969 |
| altitude trends in conifer leaf morphology and stable carbon isotope composition. | the natural ratio of stable carbon isotopes (δ(13)c) was compared to leaf structural and chemical characteristics in evergreen conifers in the north-central rockies, united states. we sought a general model that would explain variation in δ(13)c across altitudinal gradients. because variation in δ(13)c is attributed to the shifts between supply and demand for carbon dioxide within the leaf, we measured structural and chemical variables related to supply and demand. we measured stomatal density, ... | 2000 | 28308741 |
| autumn stomatal closure in six conifer species of the central rocky mountains. | environmental and water relations parameters during fall were monitored for six conifer tree species common to the central rocky mountains growing naturally at the same location (pinus contorta, pinus ponderosa, pinus flexilus, pseudotsuga menziesii, abies lasiocarpa, picea engelmannii). subsequent to what appeared to be the beginning of seasonal stomatal closure, leaf conductance to water vapor declined sharply following the onset of freezing air temperatures at night. a coincident rapid declin ... | 1984 | 28311019 |
| inter- and intraspecific polymorphism at chloroplast ssr loci and the inheritance of plastids in pinus radiata d. don. | dna sequence analysis of chloroplast genomes has revealed many short nucleotide repeats analogous to nuclear microsatellites, or simple sequence repeats (ssrs). we designed pcr primers flanking five of these regions identified in the chloroplast sequence from pinus thunbergii and tested them for amplification in pinus radiata, p. elliotii, p. taeda, p. strobus, pseudotsuga menziesii, cupressus macrocarpa, four new zealand native conifer species (podocarpus totara, podocarpus hallii, podocarpus n ... | 1996 | 24162352 |
| species-mediated soil moisture availability and patchy establishment of pseudotsuga menziesii in chaparral. | the occurrence of mature individuals of pseudotsuga menziesii in stands of arctostaphylos species mark the initial stages of mixed evergreen forest invasion into chaparral in central coastal california. we planted two cohorts of p. menziesii seeds at three sites under stands of two arctostaphylos species and adenostoma fasciculatum in order to determine whether first-year seedling emergence and survival, particularly during the regular summer drought, underlie the spatial distribution of mature ... | 1999 | 28308157 |
| forest floor leachate fluxes under six different tree species on a metal contaminated site. | trees play an important role in the biogeochemical cycling of metals, although the influence of different tree species on the mobilization of metals is not yet clear. this study examined effects of six tree species on fluxes of cd, zn, doc, h(+) and base cations in forest floor leachates on a metal polluted site in belgium. forest floor leachates were sampled with zero-tension lysimeters in a 12-year-old post-agricultural forest on a sandy soil. the tree species included were silver birch (betul ... | 2013 | 23376521 |
| the population biology of bromus tectorum in forests: effect of disturbance, grazing, and litter on seedling establishment and reproduction. | the effect of tree canopy, understory, herbivores, and litter depth on seedling establishment, survival, and reproduction of the alien grass, bromus tectorum (cheatgrass), was examined in a series of experiments in four forest habitat types in western north america. higher recruitment, survival, and reproduction on clearcuts, which would be expected if the overstory alone is limiting the distribution of cheatgrass in forests, were not observed. removing the understory in an otherwise undisturbed ... | 1990 | 28312970 |
| chloroplast dna restriction fragment length polymorphism in sequoia sempervirens d. don endl., pseudotsuga menziesii (mirb.) franco, calocedrus decurrens (torr.), and pinus taeda l. | the extent and type of chloroplast dna restriction fragment length polymorphism was determined among individual tree samples of coast redwood, douglas fir, incense-cedar, and loblolly pine. a total of 107 trees was surveyed for three restriction enzymes (bamhi, ecori, hindiii) and six chloroplast dna probes from petunia (p3, p4, p6, p8, p10, s8). the probes comprise 64% of the petunia chloroplast genome. polymorphisms were detected in all species but loblolly pine. coast redwood and incense-ceda ... | 1991 | 24221163 |
| comparative quantitation of abscisic acid in plant extracts by gas-liquid chromatography and an enzyme-linked immunosorbent assay using the avidin-biotin system. | in this report we describe an enzyme-linked immunosorbent assay (elisa) for the quantitation of abscisic acid (aba) in plant extracts. a microtitration plate is coated with an aba-protein complex. the aba, standard or sample, is then added to each well with a limiting quantity of rabbit anti-aba antibodies. during the following incubation period, antibodies bind either to free or to bound aba on the plates. after washing, bound antibodies are indirectly labelled in two steps by the means of biot ... | 1985 | 24241618 |
| novel resistance measurement method: analysis of accuracy and thermal dependence with applications in fiber materials. | material resistance is important since different physicochemical properties can be extracted from it. this work describes a novel resistance measurement method valid for a wide range of resistance values up to 100 gω at a low powered, small sized, digitally controlled and wireless communicated device. the analog and digital circuits of the design are described, analysing the main error sources affecting the accuracy. accuracy and extended uncertainty are obtained for a pattern decade box, showin ... | 2016 | 27983652 |
| application of proteomics to the study of pollination drops. | | 2013 | 25202539 |
| defoliation of interior douglas-fir elicits carbon transfer and stress signalling to ponderosa pine neighbors through ectomycorrhizal networks. | extensive regions of interior douglas-fir (pseudotsuga menziesii var. glauca, idf) forests in north america are being damaged by drought and western spruce budworm (choristoneura occidentalis). this damage is resulting from warmer and drier summers associated with climate change. to test whether defoliated idf can directly transfer resources to ponderosa pine (pinus ponderosae) regenerating nearby, thus aiding in forest recovery, we examined photosynthetic carbon transfer and defense enzyme resp ... | 2015 | 25683155 |
| role of douglas fir (pseudotsuga menziesii) carbohydrates in resistance to budworm (choristoneura occidentalis). | the current year's growth of douglas fir contains galactose, unusual in that this carbohydrate makes up 78.7% of the total carbohydrate fraction. an agar diet study was undertaken to determine the effects of galactose, other carbohydrates, and terpenes on western spruce budworm larval mortality, growth rate, and adult biomas production. all concentrations of the carbohydrates and terpenes tested, as well as other mineral elements not tested, were typical of the current year's foliage of douglas ... | 1994 | 24242063 |
| technique for using microencapsulated terpenes in lepidopteran artificial diets. | we have developed and tested a technique to microencapsulate terpene compounds by forming gelatin-walled microcapsules around the terpene essential oils. eight terpenes that are common constituents of douglas fir (pseudotsuga menziesii) oleoresin were encapsulated, including five monoterpenes (α-pinene,β-pinene, camphene, myrcene, and limonene) and three oxygenated monoterpenes (bornyl acetate, linalool, andβ-citronellol). the encapsulated terpenes were mixed into artificial diets to determine t ... | 1992 | 24253865 |
| responses of the western spruce budworm to varying levels of nitrogen and terpenes. | an agar diet study using western spruce budworm populations from idaho and new mexico was carried out to determine the effects of varying concentrations of nitrogen, beta-pinene, and bornyl acetate on larval growth and survival. increased availability of nitrogen resulted in increased larval growth rate and survival to the adult stage. larval growth rates from the idaho population were higher on the high-nitrogen diet than were growth rates from the new mexico population. the high level of beta- ... | 1987 | 28312304 |
| douglas-fir (pseudotsuga menziesii)-spruce budworm (choristoneura occidentalis) interactions: the effect of nutrition, chemical defenses, tissue phenology, and tree physical parameters on budworm success. | measurements of foliage quality, physiological, and phenological condition of sample trees were used as independent variables in multiple correlation analyses to determine their effect on female and male spruce budworm larval dry weights. female budworm from trees high in foliar concentrations of beta-pinene, myrcene and total nitrogen weighed less than those from trees lacking these characteristics. male budworm from trees high in foliar concentrations of alpha-pinene, myrcene, terpinolene, cit ... | 1984 | 28310739 |
| chemical compositions of essential oils of five introduced conifers in corsica. | the aim of this survey was to determine the chemical composition of essential oils (eo) of five conifers acclimated in corsica by gc(ri), gc-ms and (13)c nmr. l. decidua needle and wood eos contained as majors components: α- and β-pinenes, germacrene d (needles) and bornyl acetate (wood). the eos of needles, wood and cones of p. menziesii were characterised by β- and α-pinenes, terpinen-4-ol, sabinene, terpinolene (needles and wood), δ-3-carene (wood) and limonene (cones). needles and wood eos o ... | 2017 | 28278672 |
| diversity and inheritance of inter-simple sequence repeat polymorphisms in douglas-fir (pseudotsuga menziesii) and sugi (cryptomeria japonica). | we studied inter-simple sequence repeat (issr) polymorphism and inheritance in douglas-fir [pseudotsuga menziesii (mirb.) franco] and sugi (cryptomeria japonica d. don) megagametophytes using primers that anneal to simple repeats of various lengths, sequences, and non-repetitive motifs at the 5' and 3' ends. products were visualized on agarose gels with ethidium bromide staining. more than 60% of the 96 primers tested gave interpretable banding patterns in both douglas-fir and sugi, and the usef ... | 1996 | 24166114 |
| shoot excision has no effect on net flux of protons, ammonium or nitrate in seedling roots of a conifer and three crop species. | a high-flux region, 5mm from the root tips of seedlings of coastal douglas-fir (pseudotsuga menziesii), soybean (glycine max), zucchini (cucurbita pepo) and pea (pisum sativum), was monitored using a microelectrode ion flux measurement system, for changes in the net fluxes of h(+), nh(4)(+) and no(3)(-) in response to shoot removal. in all species, careful excision of the seedling shoot had no significant effect on the net fluxes of h(+), nh(4)(+) or no(3)(-) measured 5mm from the root tip. expe ... | 2012 | 22494824 |
| fortifying the forest: thinning and burning increase resistance to a bark beetle outbreak and promote forest resilience. | fire frequency in low-elevation coniferous forests in western north america has greatly declined since the late 1800s. in many areas, this has increased tree density and the proportion of shade-tolerant species, reduced resource availability, and increased forest susceptibility to forest insect pests and high-severity wildfire. in response, treatments are often implemented with the goal of increasing ecosystem resilience by increasing resistance to disturbance. we capitalized on an existing repl ... | 2016 | 27755724 |
| volatile and within-needle terpene changes to douglas-fir trees associated with douglas-fir beetle (coleoptera: curculionidae) attack. | mass attack by tree-killing bark beetles (curculionidae: scolytinae) brings about large chemical changes in host trees that can have important ecological consequences. for example, mountain pine beetle (dendroctonus ponderosae hopkins) attack increases emission of terpenes by lodgepole pine (pinus contorta dougl. ex loud.), affecting foliage flammability with consequences for wildfires. in this study, we measured chemical changes to douglas-fir (pseudotsuga menziesii var. glauca (mirb.) franco) ... | 2016 | 27231258 |
| bark beetle effects on fuel profiles across a range of stand structures in douglas-fir forests of greater yellowstone. | consequences of bark beetle outbreaks for forest wildfire potential are receiving heightened attention, but little research has considered ecosystems with mixed-severity fire regimes. such forests are widespread, variable in stand structure, and often fuel limited, suggesting that beetle outbreaks could substantially alter fire potentials. we studied canopy and surface fuels in interior douglas-fir (pseudotsuga menziesii v. glauca) forests in greater yellowstone, wyoming, usa, to determine how f ... | 2013 | 23495632 |
| leaf water (18) o and (2) h enrichment along vertical canopy profiles in a broadleaved and a conifer forest tree. | distinguishing meteorological and plant-mediated drivers of leaf water isotopic enrichment is prerequisite for ecological interpretations of stable hydrogen and oxygen isotopes in plant tissue. we measured input and leaf water δ(2) h and δ(18) o as well as micrometeorological and leaf morpho-physiological variables along a vertical gradient in a mature angiosperm (european beech) and gymnosperm (douglas fir) tree. we used these variables and different enrichment models to quantify the influence ... | 2017 | 28042668 |
| nitrogen addition enhances drought sensitivity of young deciduous tree species. | understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. although there is evidence on the mode of nitrogen (n) and drought (d) effects on tree growth, our understanding of the interplay of these factors is still limited. simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of n addition and d on the productivity of three tree specie ... | 2016 | 27499761 |
| comparison of leaf gas exchange and stable isotope signature of water-soluble compounds along canopy gradients of co-occurring douglas-fir and european beech. | combined δ(13) c and δ(18) o analyses of water-soluble leaf and twig phloem material were used to determine intrinsic water-use efficiency (iwue) and variability of stomatal conductance at different crown positions in adult european beech (fagus sylvatica) and douglas-fir (pseudotsuga menziesii) trees. simultaneous gas exchange measurements allowed evaluation of the differences in calculating iwue from leaf or phloem water-soluble compounds, and comparison with a semi-quantitative dual isotope m ... | 2012 | 22292498 |
| evolution of the yabby gene family in seed plants. | members of the yabby gene family of transcription factors in angiosperms have been shown to be involved in the initiation of outgrowth of the lamina, the maintenance of polarity, and establishment of the leaf margin. although most of the dorsal-ventral polarity genes in seed plants have homologs in non-spermatophyte lineages, the presence of yabby genes is restricted to seed plants. to gain insight into the origin and diversification of this gene family, we reconstructed the evolutionary history ... | 2016 | 26763689 |