Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
liquid chromatographic determination of rh-5992, an ecdysone agonist, in some forestry matrixes.a liquid chromatographic method is described for the analysis of rh-5992 (n'-t-butyl-n'-[3,5-dimethyl-benzoyl]-n- [-ethylbenzoyl]hydrazine) from various terrestrial and aquatic forestry matrixes and stream water. the processed soils, litter, oak foliage, sediment, aquatic plants, and fish were extracted with a mixture of acetone and water; balsam fir needles were extracted with acidified methanol solution; stream water was extracted with dichloromethane. aliquots of crude extracts were solvent p ...20088318862
element mobility and partitioning along a soil acidity gradient in central ontario forests, canada.the potential environmental risk posed by metals in forest soils is typically evaluated by modeling metal mobility using soil-solution partitioning coefficients (k(d)), although such information is generally restricted to a few well-studied metals. soil-solution partitioning coefficients were determined for 17 mineral elements (al, as, be, ba, ca, cr, cu, fe, ga, k, li, mg, rb, sr, tl, u and v) in a-horizon (0-5 cm) soil at 46 forested sites that border the precambrian shield in central ontario, ...200818058024
ecophysiology and growth of advance red spruce and balsam fir regeneration after partial cutting in yellow birch-conifer stands.we investigated ecophysiological and growth responses of short (0.4 to 1.3 m in height) advance regeneration of red spruce (picea rubens sarg.) and balsam fir (abies balsamea l.) six years after removal of 0, 40, 50, 60 and 100% of the overstory basal area (ba) in two yellow birch-conifer stands. partial cuts significantly increased stomatal conductance of red spruce only. light-saturated photosynthesis (leaf-area basis) of both species increased with ba removal, but unlike red spruce, specific ...200818519253
seasonal changes in abundance and phosphorylation status of photosynthetic proteins in eastern white pine and balsam fir.during winter, the light-harvesting complexes of evergreen plants change function from energy-harvesting to energy-dissipating centers. the goal of our study was to monitor changes in the composition of the photosynthetic apparatus that accompany these functional changes. seasonal changes in chlorophyll fluorescence, pigment concentration, and abundance and phosphorylation status of photosynthetic proteins in pinus strobus l. (sun-exposed trees) and abies balsamea (l.) p. mill. (sun-exposed and ...200919203960
host tree age as a selective pressure leading to local adaptation of a population of a polyphagous lepidoptera in virgin boreal forest.we tested the hypothesis that host tree age may act as a selective factor and lead to local adaptation of the hemlock looper (lambdina fiscellaria), a geometrid lepidoptera that has a wide geographical distribution and has evolved in different eco-zones characterized by different levels of floristic composition, age structure and fragmentation level. considering that hemlock looper outbreaks mainly occurred in old forests, we compared the biological performances of two populations. the first pop ...200919224661
anti-insect secondary metabolites from fungal endophytes of conifer trees.choristoneura fumiferana is the most economically-important insect pest in eastern north america. historically, strategies to control epidemics have relied on chemical pesticides that are no longer approved for use. the presence of fungal endophytes in cool area grass species and their role in reducing the impact of herbivorous insects is well understood. recent work has demonstrated that foliar endophytes of conifers also produce anti-insect toxins. field and nursery studies testing trees infec ...200919967982
wood formation in abies balsamea seedlings subjected to artificial defoliation.we determined the cambial sensitivity and quantified the anatomical differences in xylem of abies balsamea (l.) mill. seedlings subjected to artificial defoliation to simulate spruce budworm feeding. defoliation was performed by removing two-thirds of needles of all current-year shoots for up to four consecutive growth cycles to account for inter- and intra-annual xylem formation. in experiment 1, xylem development was studied from may to october 2005 in seedlings defoliated at the end of june. ...200919203970
boring in response to bark and phloem extracts from north american trees does not explain host acceptance behavior of orthotomicus erosus (coleoptera: scolytidae).when invasive herbivorous insects encounter novel plant species, they must determine whether the novel plants are hosts. the mediterranean pine engraver, orthotomicus erosus (wollaston), an exotic bark beetle poised to expand its range in north america, accepts hosts after contacting the bark. to test the hypothesis that o. erosus accepts hosts on the basis of gustatory cues, we prepared bark and phloem extracts from logs of four north american tree species that we had used in previous host acce ...201020388300
forest restoration in a mixed-ownership landscape under climate change.the extent to which current landscapes deviate from the historical range of natural variability (rnv) is a common means of defining and ranking regional conservation targets. however, climate-induced shifts in forest composition may render obsolete restoration strategies and conservation targets based on historic climate conditions and disturbance regimes. we used a spatially explicit forest ecosystem model, landis-ii, to simulate the interaction of climate change and forest management in northe ...201020405791
wood losses and economical threshold of btk aerial spray operation against spruce budworm.spruce budworm, choristoneura fumiferana (clem.), causes cumulative defoliation and hence annual growth loss of the balsam fir, abies balsamea (l.) mill, host tree. annual growth increments of mixed balsam fir stands were measured by stem analysis over a 9 year period (1994-2002), when bacillus thuringiensis ssp. kurstaki (btk) was applied to control spruce budworm defoliation. with this approach, it was possible to quantify the change in stand volume growth after aerial spray applications of bt ...201019938000
selected beetle assemblages captured in pitfall traps baited with deer dung or meat in balsam fir and sugar maple forests of central quebec.vertebrate dung and carrion are rich and strongly attractive resources for numerous beetles that are often closely linked to them. the presence and abundance of beetles exploiting such resources are influenced by various ecological factors including climate and forest cover vegetation. we studied selected assemblages of coprophilous and necrophagous beetles in quebec along a 115-km north-south transect in three balsam fir (abies balsamea (l.) miller) forest sites and in a fourth forest site dom ...201022127165
optimization of spray drying process for bacillus thuringiensis fermented wastewater and wastewater sludge.response surface methodology was used to optimize spray drying process for producing biopesticide powders of bacillus thuringiensis by using fermented broth of starch industry wastewater and wastewater sludge. analysis of variance was carried out using number of viable spores in the powder as dependent variable. the determination coefficients of models were 92 and 94% for fermented broth of starch industry wastewater and wastewater sludge, respectively. under the optimal conditions of the operat ...201120835715
cree antidiabetic plant extracts display mechanism-based inactivation of cyp3a4.seventeen cree antidiabetic medicinal plants were studied to determine their potential to inhibit cytochrome p450 3a4 (cyp3a4) through mechanism-based inactivation (mbi). the ethanolic extracts of the medicinal plants were studied for their inhibition of cyp3a4 using the substrates testosterone and dibenzylfluorescein (dbf) in high pressure liquid chromatography (hplc) and microtiter fluorometric assays, respectively. using testosterone as a substrate, extracts of alnus incana, sarracenia purpur ...201121186373
host associations between fungal root endophytes and boreal trees.fungal root endophytes colonize root tissue concomitantly with mycorrhizal fungi, but their identities and host preferences are largely unknown. we cultured fungal endophytes from surface-sterilized cenococcum geophilum ectomycorrhizae of betula papyrifera, abies balsamea, and picea glauca from two boreal sites in eastern canada. isolates were initially grouped on the basis of cultural morphology and then identified by internal transcribed spacer ribosomal dna sequencing or by pcr restriction fr ...201121475991
site factors and management influence short-term host resistance to spruce budworm, choristoneura fumiferana (clem.), in a species-specific manner.background: this study examined the interactions between thinning and soil drainage classes on the resistance of balsam fir, abies balsamea (l.) mill, white spruce, picea glauca (moench) voss, and black spruce, p. mariana (mill.) bsp, to spruce budworm, choristoneura fumiferana (clem.), defoliation 1 year after treatment. to estimate host tree resistance, foliage production and larval foliage consumption were determined to generate an index of resistance quantifying the amount of residual foliag ...201121796758
two-dimensional wavelet analysis of spruce budworm host basal area in the border lakes landscape.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. however, to what extent historical forest management has influenced current spatial patterns of spruce budworm host species is unknown. to identify landsc ...201121939054
effects of soil moisture manipulations on fine root dynamics in a mature balsam fir (abies balsamea l. mill.) forest.we tested the hypothesis that moisture stress affects fine root dynamics during and after the stress. to this end, we investigated the effects of soil moisture on annual and seasonal fine root production and mortality over 4 years in a mature balsam fir (abies balsamea l. mill.) stand using a minirhizotron and soil coring. droughting and irrigating treatments were imposed for 17 weeks during the third year of the study, and post-treatment recovery was measured during the fourth year. monthly fin ...201121489968
transcriptomic responses of the softwood-degrading white-rot fungus phanerochaete carnosa during growth on coniferous and deciduous wood.to identify enzymes that could be developed to reduce the recalcitrance of softwood resources, the transcriptomes of the softwood-degrading white-rot fungus phanerochaete carnosa were evaluated after growth on lodgepole pine, white spruce, balsam fir, and sugar maple and compared to the transcriptome of p. carnosa after growth on liquid nutrient medium. one hundred fifty-two million paired-end reads were obtained, and 63% of these reads were mapped to 10,257 gene models from p. carnosa. five-hun ...201121441342
species composition of saproxylic fungal communities on decaying logs in the boreal forest.coarse woody debris supports large numbers of saproxylic fungal species. however, most of the current knowledge comes from scandinavia and studies relating the effect of stand or log characteristics on the diversity and composition of decomposer fungi have not been conducted in northeastern canada. logs from five tree species were sampled along a decomposition gradient in nine stands representing three successional stages of the boreal mixed forest of northwestern quebec, canada. using a molecul ...201121246195
episodic recruitment of the seedling banks in balsam fir and white spruce. 201223204491
comparing modern and presettlement forest dynamics of a subboreal wilderness: does spruce budworm enhance fire risk?insect disturbance is often thought to increase fire risk through enhanced fuel loadings, particularly in coniferous forest ecosystems. yet insect disturbances also affect successional pathways and landscape structure that interact with fire disturbances (and vice-versa) over longer time scales. we applied a landscape succession and disturbance model (landis-ii) to evaluate the relative strength of interactions between spruce budworm (choristoneura fumiferana) outbreaks and fire disturbances in ...201222827135
abibalsamins a and b, two new tetraterpenoids from abies balsamea oleoresin.abibalsamins a (1) and b (2), two unprecedented tetraterpenoids featuring a 3,4-seco-rearranged lanostane system fused with a β-myrcene lateral chain via a [4 + 2] diels-alder cycloaddition, were isolated from the oleoresin of abies balsamea. their structures were elucidated by means of extensive 2d nmr, ir, and ms spectroscopy analyses. the absolute configuration of 1 was determined by single-crystal x-ray diffraction. both compounds exhibited significant cytotoxic activity against cancer cell ...201222394397
bifunctional cis-abienol synthase from abies balsamea discovered by transcriptome sequencing and its implications for diterpenoid fragrance production.the labdanoid diterpene alcohol cis-abienol is a major component of the aromatic oleoresin of balsam fir (abies balsamea) and serves as a valuable bioproduct material for the fragrance industry. using high-throughput 454 transcriptome sequencing and metabolite profiling of balsam fir bark tissue, we identified candidate diterpene synthase sequences for full-length cdna cloning and functional characterization. we discovered a bifunctional class i/ii cis-abienol synthase (abcas), along with the pa ...201222337889
mode of coniferous wood decay by the white rot fungus phanerochaete carnosa as elucidated by ftir and tof-sims.the softwood degrading white-rot fungus, phanerochaete carnosa, was investigated for its ability to degrade two coniferous woods: balsam fir and lodgepole pine. p. carnosa grew similarly on these wood species, and like the hardwood-degrading white-rot fungus ceriporiopsis subvermispora, p. carnosa demonstrated selective degradation of lignin, as observed by fourier transform infrared spectroscopy and time-of-flight secondary ion mass spectrometry (tof-sims). lignin degradation across cell walls ...201222290642
transmission of a gammabaculovirus within cohorts of balsam fir sawfly (neodiprion abietis) larvae.nucleopolyhedroviruses (npv: gammabaculovirus: baculoviridae) of diprionid sawflies (diprionidae: hymenoptera) are highly host specific and only infect the midgut epithelium. while still alive, infected sawfly larvae excrete npv-laden diarrhea that contaminates food sources. the diarrhea can then be consumed by conspecific larvae, resulting in rapid horizontal transmission of the virus. to better understand the efficacy of gammabaculovirus-based biological control products, the horizontal spread ...201226466722
spread of a gammabaculovirus within larval populations of its natural balsam fir sawfly (neodiprion abietis) host following its aerial application.field trials and assessments of the balsam fir sawfly (neodiprion abietis) nucleopolyhedrovirus (neabnpv: baculoviridae, gammabaculovirus) against its natural host were conducted in july and august 2002 near corner brook, newfoundland and labrador, canada, in naturally regenerated, precommercially thinned stands dominated by balsam fir (abies balsamea). two experimental blocks, each with its own untreated control, were established. the purpose of the island pond block was to examine the spread o ...201226466719
carry-over effect of host nutritional quality on performance of spruce budworm progeny.the effect of host nutritional quality on spruce budworm (choristoneura fumiferana (clemens)) parental and offspring performance was studied using field and laboratory rearing experiments, and foliar chemical analyses. foliage of balsam fir (abies balsamea (l.) mill.), white spruce (picea glauca (moench) voss) and black spruce (p. mariana (mill.) bsp) was used to rear the parental generation in the field, whereas an artificial diet was used to rear the progeny under laboratory conditions. import ...201222077965
recovery kinetics of photochemical efficiency in winter stressed conifers: the effects of growth light environment, extent of the season and species.evergreens undergo reductions in maximal photochemical efficiency (f(v)/f(m)) during winter due to increases in sustained thermal energy dissipation. upon removing winter stressed leaves to room temperature and low light, f(v)/f(m) recovers and can include both a rapid and a slow phase. the goal of this study was to determine whether the rapid component to recovery exists in winter stressed conifers at any point during the season in a seasonally extreme environment. additional goals were to comp ...201322575048
ontogeny and stand condition influence the dispersal behavior of a defoliating specialist caterpillar.a 4-yr field study was carried out to study the dispersal behavior of young larvae of the eastern spruce budworm (choristoneura fumiferana clemens) (lepidoptera: tortricidae) within and between crowns of balsam fir (abies balsamea (l.) miller), through the peak to decline of an outbreak. newly hatched neonates, searching for overwintering sites in the fall, were frequently captured in sticky traps as they dispersed via "ballooning" (on silken threads) between and within tree crowns. a relatively ...201324216325
a large herbivore triggers alternative successional trajectories in the boreal forest.alternative successional trajectories (ast) may result in multiple climax states within an ecosystem when disturbances affect colonization history. in the boreal forest, ungulates have been proposed to drive ast because, under herbivore pressure, preferred species may go extinct and apparent competition may benefit browsing-resistant species. over a 15-year period following logging, we tested whether deer herbivory altered plant species composition and whether the competitive advantage of resist ...201324597230
interspecific coordination and intraspecific plasticity of fine root traits in north american temperate tree species.fine roots play an important role in nutrient and water absorption and hence overall tree performance. however, current understanding of the ecological role of belowground traits lags considerably behind those of aboveground traits. in this study, we used data on specific root length (srl), fine root diameter (d) and branching intensity (bi) of two datasets to examine interspecific trait coordination as well as intraspecific trait variation across ontogenetic stage and soil conditions (i.e., pla ...201323874347
the action of antidiabetic plants of the canadian james bay cree traditional pharmacopeia on key enzymes of hepatic glucose homeostasis.we determined the capacity of putative antidiabetic plants used by the eastern james bay cree (canada) to modulate key enzymes of gluconeogenesis and glycogen synthesis and key regulating kinases. glucose-6-phosphatase (g6pase) and glycogen synthase (gs) activities were assessed in cultured hepatocytes treated with crude extracts of seventeen plant species. phosphorylation of amp-dependent protein kinase (ampk), akt, and glycogen synthase kinase-3 (gsk-3) were probed by western blot. seven of th ...201323864882
initial responses of rove and ground beetles (coleoptera, staphylinidae, carabidae) to removal of logging residues following clearcut harvesting in the boreal forest of quebec, canada.increased interest in biomass harvesting for bioenergetic applications has raised questions regarding the potential ecological consequences on forest biodiversity. here we evaluate the initial changes in the abundance, species richness and community composition of rove (staphylinidae) and ground beetles (carabidae), immediately following 1) stem-only harvesting (soh), in which logging debris (i.e., tree tops and branches) are retained on site, and 2) whole-tree harvesting (wth), in which stems, ...201323653498
the effects of throughfall exclusion on xylogenesis of balsam fir.a 20-40% reduction in soil moisture is projected for the boreal forest of eastern canada for the period 2070-99 relative to 1971-2000. in order to better predict the effects of a reduced water supply on the growth of balsam fir (abies balsamea (l.) mill.), a dominant tree species of the boreal forest, we simulated 2 consecutive years of summer droughts (starting in july) by means of throughfall exclusion. four 100-m(2) plots were established in 2010 with polyethylene sheets maintained 1.3-2 m ab ...201323604743
antioxidant potential of bark extracts from boreal forest conifers.the bark of boreal forest conifers has been traditionally used by native americans to treat various ailments and diseases. some of these diseases involve reactive oxygen species (ros) that can be prevented by the consumption of antioxidants such as phenolic compounds that can be found in medicinal plants. in this study, ultrasonic assisted extraction has been performed under various solvent conditions (water:ethanol mixtures) on the bark of seven boreal forest conifers used by native americans i ...201326784337
fenitrothion and aminocarb residues in water and balsam fir foliage following spruce budworm spraying programs in quebec, 1979 to 1982. 20133697537
lanostane- and cycloartane-type triterpenoids from abies balsamea oleoresin.phytochemical analysis of a. balsamea oleoresin led to the isolation of three new 3,4-seco-lanostane triterpenoids 1-3, one new cycloartane triterpenoid 4 along with fourteen known terpenoids. structure determinations were based on extensive 1d/2d nmr, ir and ms spectroscopic analyses, and comparison with literature data. the isolated compounds were evaluated in vitro for their cytotoxicity against human cell lines (a549, dld-1, ws1) and their antibacterial activity against e. coli and s. aureus ...201323946828
molecular and microscopic analysis of the gut contents of abundant rove beetle species (coleoptera, staphylinidae) in the boreal balsam fir forest of quebec, canada.experimental research on beetle responses to removal of logging residues following clearcut harvesting in the boreal balsam fir forest of quebec revealed several abundant rove beetle (staphylinidae) species potentially important for long-term monitoring. to understand the trophic affiliations of these species in forest ecosystems, it was necessary to analyze their gut contents. we used microscopic and molecular (dna) methods to identify the gut contents of the following rove beetles: atheta caps ...201324294095
biodiversity elements vulnerable to climate change in the catskill high peaks subecoregion (ulster, delaware, sullivan, and greene counties, new york state).climate change is expected to affect biodiversity elements in the catskill high peaks subecoregion of new york state with effects that are difficult to predict. the present communication details the species and communities of greatest conservation concern in this portion of the state and makes recommendations for monitoring the most pressing climate change-biodiversity vulnerabilities. specifically, we present sites for monitoring representative old-growth and successional stands of red spruce/b ...201325098491
history of the spruce-fir forest in the catskill mountains of new york.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 c ...201325098490
xylem formation can be modeled statistically as a function of primary growth and cambium activity.primary (budburst, foliage and shoot) growth and secondary (cambium and xylem) growth of plants play a vital role in sequestering atmospheric carbon. however, their potential relationships have never been mathematically quantified and the underlying physiological mechanisms are unclear. we monitored primary and secondary growth in picea mariana and abies balsamea on a weekly basis from 2010 to 2013 at four sites over an altitudinal gradient (25-900 m) in the eastern canadian boreal forest. we de ...201424861414
influence of partial cutting on parasitism of endemic spruce budworm (lepidoptera: tortricidae) populations.silvicultural treatments such as thinning have been suggested as management tools against the spruce budworm, choristoneura fumiferana (clemens) (lepidoptera: tortricidae). among other things, parasitoids are also proposed to be influenced by silvicultural procedures, but the effect of thinning on spruce budworm's natural enemies has not been tested yet. in this study, the influence of partial cutting on parasitism of endemic spruce budworm populations has been investigated in mature balsam fir- ...201424780195
a molecular identification protocol for roots of boreal forest tree species. 201425383267
inhibition of insect glutathione s-transferase (gst) by conifer extracts.insecticide synergists biochemically inhibit insect metabolic enzyme activity and are used both to increase the effectiveness of insecticides and as a diagnostic tool for resistance mechanisms. considerable attention has been focused on identifying new synergists from phytochemicals with recognized biological activities, specifically enzyme inhibition. jack pine (pinus banksiana lamb.), black spruce (picea mariana (mill.) bsp.), balsam fir (abies balsamea (l.) mill.), and tamarack larch (larix l ...201425270601
biogeographic variation in evergreen conifer needle longevity and impacts on boreal forest carbon cycle projections.leaf life span is an important plant trait associated with interspecific variation in leaf, organismal, and ecosystem processes. we hypothesized that intraspecific variation in gymnosperm needle traits with latitude reflects both selection and acclimation for traits adaptive to the associated temperature and moisture gradient. this hypothesis was supported, because across 127 sites along a 2,160-km gradient in north america individuals of picea glauca, picea mariana, pinus banksiana, and abies b ...201425225397
soil response to a 3-year increase in temperature and nitrogen deposition measured in a mature boreal forest using ion-exchange membranes.the projected increase in atmospheric n deposition and air/soil temperature will likely affect soil nutrient dynamics in boreal ecosystems. the potential effects of these changes on soil ion fluxes were studied in a mature balsam fir stand (abies balsamea [l.] mill) in quebec, canada that was subjected to 3 years of experimentally increased soil temperature (+4 °c) and increased inorganic n concentration in artificial precipitation (three times the current n concentrations using nh4no3). soil el ...201425139238
genetic evidence for three discrete taxa of melampsora (pucciniales) affecting willows (salix spp.) in new york state.rust fungi in the genus melampsora (pucciniales) are the most important pathogens of shrub willows (salix spp.) cultivated for biomass in new york state and temperate regions worldwide. the taxonomy and species identification of these fungi historically have been problematic as they are morphologically indistinguishable on willow and often have complex life histories. melampsora of salix in north america, therefore, have been circumscribed to the collective species melampsora epitea thüm. and fu ...201425110133
the persistence and fate of fenitrothion insecticide in a forest environment. ii. accumulation of residues in balsam fir foliage. 20144433873
physiology and growth of advance picea rubens and abies balsamea regeneration following different canopy openings.we examined the ecophysiology and growth of 0.3-1.3 m tall advance red spruce (picea rubens sarg.) and balsam fir (abies balsamea [l.] mill.) regeneration during a 5-year period following the application of different harvest types producing three sizes of canopy openings: (i) small gaps (<100 m(2) in area; sma) created by partial uniform single-tree harvest; (ii) irregular gaps of intermediate size (100-300 m(2); int) created by group-selection harvest (removal of groups of trees, mainly balsam ...201424443326
repellent effectiveness of seven plant essential oils, sunflower oil and natural insecticides against horn flies on pastured dairy cows and heifers.plant essential oils (basil, geranium, balsam fir, lavender, lemongrass, peppermint, pine and tea tree), mixed with either sunflower oil or ethyl alcohol, were applied at 5% concentrations to the sides of holstein cattle. pastured cattle treated with essential oils diluted in sunflower oil had less flies than the untreated control for a 24-h period. however, the essential oil treatments were not significantly different than the carrier oil alone. barn-held heifers treated with essential oils and ...201424382265
seedling ontogeny and environmental plasticity in two co-occurring shade-tolerant conifers and implications for environment-population interactions.seedling success is determined by evolved strategies of intrinsic genetic programming and plasticity that are regulated by extrinsic pathways. we tested the relative importance of these mechanisms in red spruce (picea rubens sarg.) and balsam fir (abies balsamea lin.), which share understory regeneration niches in northeastern north america. although its reproductive effort is adequate, spruce has decreased in abundance, in relation to fir, in seedling and sapling populations, even in forests th ...201424368754
canadian boreal pulp and paper feedstocks contain neuroactive substances that interact in vitro with gaba and dopaminergic systems in the brain.pulp and paper wood feedstocks have been previously implicated as a source of chemicals with the ability to interact with or disrupt key neuroendocrine endpoints important in the control of reproduction. we tested nine canadian conifers commonly used in pulp and paper production as well as 16 phytochemicals that have been observed in various pulp and paper mill effluent streams for their ability to interact in vitro with the enzymes monoamine oxidase (mao), glutamic acid decarboxylase (gad), and ...201424041600
composition of the spruce budworm (choristoneura fumiferana) midgut microbiota as affected by rearing conditions.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 insec ...201526636571
understanding the physiology of postharvest needle abscission in balsam fir.balsam fir (abies balsamea) trees are commonly used as a specialty horticultural species for christmas trees and associated greenery in eastern canada and united states. postharvest needle abscission has always been a problem, but is becoming an even bigger challenge in recent years presumably due to increased autumn temperatures and earlier harvesting practices. an increased understanding of postharvest abscission physiology in balsam fir may benefit the christmas tree industry while simultaneo ...201526635863
dft calculations and roesy nmr data for the diastereochemical characterization of cytotoxic tetraterpenoids from the oleoresin of abies balsamea.eight non-carotenoid tetraterpenoids, abibalsamins c-j (3-10), were isolated from the oleoresin of abies balsamea. their chemical structures were determined based on analysis of 1d/2d nmr and ms data. the assignment of their relative configurations was accomplished using homonuclear coupling constants in tandem with roesy data. however, the presence of two stereogenic centers on a flexible side chain complicated the characterization. in silico models and roesy data were analyzed in order to assi ...201526592897
combining near infrared spectra of feces and geostatistics to generate forage nutritional quality maps across landscapes.an important asset for the management of wild ungulates is recognizing the spatial distribution of forage quality across heterogeneous landscapes. to do so typically requires knowledge of which plant species are eaten, in what abundance they are eaten, and what their nutritional quality might be. acquiring such data, however, may be difficult and time consuming. here, we are proposing a rapid and cost-effective forage quality monitoring tool that combines near infrared (nir) spectra of fecal sam ...201526552270
spruce budworm (lepidoptera: tortricidae) oral secretions ii: chemistry.as sessile organisms, plants have evolved different methods to defend against attacks and have adapted their defense measures to discriminate between mechanical damage and herbivory by insects. one of the ways that plant defenses are triggered is via elicitors from insect oral secretions (os). in this study, we investigated the ability of second-instar (l2) spruce budworm [sbw; choristoneura fumiferana (clemens)] to alter the volatile organic compounds (vocs) of four conifer species [abies balsa ...201526454474
synchronisms and correlations of spring phenology between apical and lateral meristems in two boreal conifers.phenological synchronisms between apical and lateral meristems could clarify some aspects related to the physiological relationships among the different organs of trees. this study correlated the phenological phases of bud development and xylem differentiation during spring 2010-14 in balsam fir (abies balsamea mill.) and black spruce [(picea mariana mill. (bsp)] of the monts-valin national park (quebec, canada) by testing the hypothesis that bud development occurs after the reactivation of xyle ...201526377874
regulation of liver cell glucose homeostasis by dehydroabietic acid, abietic acid and squalene isolated from balsam fir (abies balsamea (l.) mill.) a plant of the eastern james bay cree traditional pharmacopeia.in our previous study, abies balsamea (l.) mill., a plant used in cree traditional medicine, had a strong effect on the regulation of glucose homeostasis in liver cells. this study aimed to isolate and identify its active constituents using a bioassay-guided fractionation approach as well as to elucidate their mechanism(s) of action. the effect of the crude extract and its constituents was evaluated on the activity of glucose-6-phosphatase (g6pase) and glycogen synthase (gs) and phosphorylation ...201526164238
carbon allocation during defoliation: testing a defense-growth trade-off in balsam fir.during repetitive defoliation events, carbon can become limiting for trees. to maintain growth and survival, the resources have to be shared more efficiently, which could result in a trade-off between the different physiological processes of a plant. the objective of this study was to assess the effect of defoliation in carbon allocation of balsam fir [abies balsamea (l.) mill.] to test the presence of a trade-off between allocation to growth, carbon storage, and defense. three defoliation inten ...201526029235
integrating phylogeography and paleoecology to investigate the origin and dynamics of hybrid zones: insights from two widespread north american firs.secondary contact between closely related taxa routinely occurs during postglacial migrations. after initial contact, the location of hybrid zones may shift geographically or remain spatially stable over time in response to various selective pressures or neutral processes. studying the extent and direction of introgression using markers having contrasted levels of gene flow can help unravel the historical dynamics of hybrid zones. thanks to their contrasted maternal and paternal inheritance, res ...201525865063
less pollen-mediated gene flow for more signatures of glacial lineages: congruent evidence from balsam fir cpdna and mtdna for multiple refugia in eastern and central north america.the phylogeographic structure and postglacial history of balsam fir (abies balsamea), a transcontinental north american boreal conifer, was inferred using mitochondrial dna (mtdna) and chloroplast dna (cpdna) markers. genetic structure among 107 populations (mtdna data) and 75 populations (cpdna data) was analyzed using bayesian and genetic distance approaches. population differentiation was high for mtdna (dispersed by seeds only), but also for cpdna (dispersed by seeds and pollen), indicating ...201525849816
composition, antimicrobial and antioxidant activities of seven essential oils from the north american boreal forest.essential oils (eos) were steam-extracted from the needles and twigs of balsam fir, black spruce, white spruce, tamarack, jack pine and eastern white cedar that remained after logging in eastern canada. these eos, similarly to that from labrador tea and other commercial eos from chinese cinnamon, clove and lemon eucalyptus, exhibited many common constituent compounds (mainly α-pinene, β-pinene, limonene and bornyl acetate) making up 91% of each oil based on gas chromatography-mass spectrometry a ...201525801172
new antibacterial hydrophobic assay reveals abies balsamea oleoresin activity against staphylococcus aureus and mrsa.oleoresin of abies balsamea (l.) mill. was used by native americans of the boreal forest of canada and french canadians to treat various infections, suggesting that oleoresin has antibacterial properties.201627769946
tree demography suggests multiple directions and drivers for species range shifts in mountains of northeastern united states.climate change is expected to lead to upslope shifts in tree species distributions, but the evidence is mixed partly due to land-use effects and individualistic species responses to climate. we examined how individual tree species demography varies along elevational climatic gradients across four states in the northeastern united states to determine whether species elevational distributions and their potential upslope (or downslope) shifts were controlled by climate, land-use legacies (past logg ...201627935175
tree phyllosphere bacterial communities: exploring the magnitude of intra- and inter-individual variation among host species.the diversity and composition of the microbial community of tree leaves (the phyllosphere) varies among trees and host species and along spatial, temporal, and environmental gradients. phyllosphere community variation within the canopy of an individual tree exists but the importance of this variation relative to among-tree and among-species variation is poorly understood. sampling techniques employed for phyllosphere studies include picking leaves from one canopy location to mixing randomly sele ...201627635335
host species identity, site and time drive temperate tree phyllosphere bacterial community structure.the increasing awareness of the role of phyllosphere microbial communities in plant health calls for a greater understanding of their structure and dynamics in natural ecosystems. since most knowledge of tree phyllosphere bacterial communities has been gathered in tropical forests, our goal was to characterize the community structure and assembly dynamics of phyllosphere epiphytic bacterial communities in temperate forests in quebec, canada. we targeted five dominant tree species: acer saccharum ...201627316353
allometric exponents as a tool to study the influence of climate on the trade-off between primary and secondary growth in major north-eastern american tree species.trees invest in both primary (e.g. height) and secondary (e.g. diameter) growth. the trade-off between these investments varies between species and changes with the tree growing environment. to better establish this trade-off, readily available allometric exponents relating height to diameter at breast height (γ(h,dbh)) and stem volume to diameter at breast height (α(v,dbh)) were simultaneously studied.201626975315
cyanobacterial gardens: the liverwort frullania asagrayana acts as a reservoir of lichen photobionts.cyanobacteria are important mediators of unrelated lichen species, which form epiphytic communities that share the same cyanobiont. no study to date, however, has considered the role of cyanobacteria as mediator between lichens and bryophytes. in the present study, dna barcoding (16s rdna, rbclx) was used to identify filamentous cyanobacteria living in close association with members of an epiphytic liverwort-lichen community on balsam fir in newfoundland. this study is the first to confirm the p ...201626929112
labeling feral spruce budworm (lepidoptera: tortricidae) populations with rubidium.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 spru ...201626920559
demographic controls of aboveground forest biomass across north america.ecologists have limited understanding of how geographic variation in forest biomass arises from differences in growth and mortality at continental to global scales. using forest inventories from across north america, we partitioned continental-scale variation in biomass growth and mortality rates of 49 tree species groups into (1) species-independent spatial effects and (2) inherent differences in demographic performance among species. spatial factors that were separable from species composition ...201626913575
pheromone-based monitoring of spruce budworm (lepidoptera: tortricidae) larvae in relation to trap position.the local abundance of male spruce budworm, choristoneura fumiferana (clemens) (lepidoptera: tortricidae), was evaluated in the province of quebec at 112 locations between 2002–2012 using pheromone-baited traps deployed on lower branches near the ground level (gl) or in the tree canopy (tc; three traps at gl and tc for each location); in addition, the presence of second instars (l2) was assessed at each location on three balsam fir branches. numbers of moths captured at gl and tc were highly cor ...201626721289
ectomycorrhizal fungal response to warming is linked to poor host performance at the boreal-temperate ecotone.rising temperatures associated with climate change have been shown to negatively affect the photosynthetic rates of boreal forest tree saplings at their southern range limits. to quantify the responses of ectomycorrhizal (em) fungal communities associated with poorly performing hosts, we sampled the roots of betula papyrifera and abies balsamea saplings growing in the b4warmed (boreal forest warming at an ecotone in danger) experiment. em fungi on the root systems of both hosts were compared fro ...201727658686
modelling moose-forest interactions under different predation scenarios at isle royale national park, usa.loss of top predators may contribute to high ungulate population densities and chronic over-browsing of forest ecosystems. however, spatial and temporal variability in the strength of interactions between predators and ungulates occurs over scales that are much shorter than the scales over which forest communities change, making it difficult to characterize trophic cascades in forest ecosystems. we applied the landis-ii forest succession model and a recently developed ungulate browsing extension ...201728263421
incorporating interspecific competition into species-distribution mapping by upward scaling of small-scale model projections to the landscape.there are a number of overarching questions and debate in the scientific community concerning the importance of biotic interactions in species distribution models at large spatial scales. in this paper, we present a framework for revising the potential distribution of tree species native to the western ecoregion of nova scotia, canada, by integrating the long-term effects of interspecific competition into an existing abiotic-factor-based definition of potential species distribution (psd). the ps ...201728207782
Refresh
firstprev
12
nextlast
Displaying items 101 - 175 of 175