| comparison of three cold hardiness tests for conifer seedlings. | greenhouse-cultured, container-grown ponderosa pine (pinus ponderosa var. scopulorum engelm.), interior douglas-fir (pseudotsuga menziesii var. glauca (beissn.) franco), and engelmann spruce (picea engelmannii (parry) engelm.) were cold acclimated and deacclimated in growth chambers over 19 weeks. cold hardiness was measured weekly by a whole-plant freeze test and by two quick tissue tests: freeze-induced electrolyte leakage of needles, and differential thermal analysis of buds. the whole-plant ... | 1990 | 14972928 |
| influence of shoot structure on light interception and photosynthesis in conifers. | the influence of shoot structure on net photosynthesis was evaluated under field conditions for the central rocky mountain (united states) conifers picea engelmannii (parry ex engelm.), abies lasiocarpa ([hook] nutt.), and pinus contorta (engelm.). in all species, the greater number of needles per unit stem length on sun shoots correlated with a smaller silhouette leaf area to total leaf area ratio (star). decreased star was due primarily to greater needle inclination toward the vertical, plus s ... | 1985 | 16664525 |
| the co-occurrence of ectomycorrhizal, arbuscular mycorrhizal, and dark septate fungi in seedlings of four members of the pinaceae. | although roots of species in the pinaceae are usually colonized by ectomycorrhizal (em) fungi, there are increasing reports of the presence of arbuscular mycorrhizal (am) and dark septate endophytic (dse) fungi in these species. the objective of this study was to determine the colonization patterns in seedlings of three pinus (pine) species (pinus banksiana, pinus strobus, pinus contorta) and picea glauca x picea engelmannii (hybrid spruce) grown in soil collected from a disturbed forest site. s ... | 2008 | 18157555 |
| use of temporal patterns in vapor pressure deficit to explain spatial autocorrelation dynamics in tree transpiration. | to quantify the relationship between temporal and spatial variation in tree transpiration, we measured sap flow in 129 trees with constant-heat sap flow sensors in a subalpine forest in southern wyoming, usa. the forest stand was located along a soil water gradient from a stream side to near the top of a ridge. the stand was dominated by pinus contorta dougl. ex loud. with picea engelmannii parry ex engelm and abies lasiocarpa (hook.) nutt. present near the stream and scattered individuals of po ... | 2008 | 18244950 |
| take me to your leader: does early successional nonhost vegetation spatially inhibit pissodes strobi (coleoptera: curculionidae)? | the spatial influences of host and nonhost trees and shrubs on the colonization patterns of white pine weevil pissodes strobi (peck) were studied within a stand of planted interior hybrid spruce [picea glauca (moench) voss x picea engelmannii (parry) ex engelm.]. planted spruce accounted for one third of all trees within the stand, whereas the remaining two thirds were comprised of early-successional nonhost vegetation, such as alder (alnus spp.), paper birch (betula papyrifera marsh.), black co ... | 2009 | 19689899 |
| effectiveness of bifenthrin (onyx) and carbaryl (sevin sl) for protecting individual, high-value conifers from bark beetle attack (coleoptera: curculionidae: scolytinae) in the western united states. | high-value trees, such as those located in residential, recreational, or administrative sites, are particularly susceptible to bark beetle (coleoptera: curculionidae: scolytinae) attack as a result of increased amounts of stress associated with drought, soil compaction, mechanical injury, or vandalism. tree losses in these unique environments generally have a substantial impact. the value of these individual trees, cost of removal, and loss of esthetics may justify protection until the main thru ... | 2006 | 17066800 |
| variability of cenococcum colonization and its ecophysiological significance for young conifers at alpine-treeline. | * plants establishing in environments that are marginal for growth could be particularly sensitive to mycorrhizal associations. we investigated ectomycorrhizal colonization and its significance for young conifers growing at, or above, their normal limits for growth, in the alpine-treeline ecotone. * colonization of seedlings (<1 yr old) and juveniles (2- to 10-yr-old) of picea engelmannii and abies lasiocarpa by cenococcum geophilum was determined in a field study, and effects of cenococcum on p ... | 2005 | 15720698 |
| relationships among cold hardiness, root growth potential and bud dormancy in three conifers. | greenhouse-cultured, container-grown ponderosa pine (pinus ponderosa var. scopulorum engelm.), interior douglas-fir (pseudotsuga menziesii var. glauca (beissn.) franco) and engelmann spruce (picea engelmannii (parry) engelm.) were cold acclimated and deacclimated in growth chambers over 19 weeks. stem cold hardiness, total new root length at 14 days and days to bud break were measured weekly. relationships among cold hardiness, root growth potential (rgp) and bud dormancy suggest that cold hardi ... | 1989 | 14972975 |
| performance of a canopy light interception model for conifer shoots, trees and stands. | a hierarchical approach was used to evaluate the behavior of a canopy light interception model using submodels for interception at levels of the shoot, crown and stand. mean silhouette areas of individual shoots of lodgepole pine (pinus contorta var. latifolia engelm.) calculated assuming spherical shoot orientation agreed well with silhouette areas measured with a video projection system. a theoretical mean silhouette to total leaf area ratio (star) calculated using measured shoot characteristi ... | 1991 | 14972866 |
| orographic cold-trapping of persistent organic pollutants by vegetation in mountains of western canada. | conifer needles from mountain areas of alberta and british columbia, canada, were collected from sites that ranged in altitude from 770 to 2200 masl and were analyzed for polychlorinated biphenyls (pcbs) and organochlorine pesticides (ocs) to determine if they are progressively concentrated in colder, more elevated mountain areas, where temperatures decrease as elevation increases. concentrations of ocs in needles ranged from 43 to 2430 pg g(-1), 55-17500 pg g(-1), and 11-2930 pg g(-1) (dry weig ... | 2003 | 12564889 |
| ectomycorrhizal specificity patterns in a mixed pinus contorta and picea engelmannii forest in yellowstone national park. | we used molecular genetic methods to test two hypotheses, (i) that host plant specificity among ectomycorrhizal fungi would be common in a closed-canopy, mixed pinus contorta-picea engelmannii forest in yellowstone national park and (ii) that specificity would be more common in the early successional tree species, p. contorta, than in the invader, p. engelmannii. we identified 28 ectomycorrhizal fungal species collected from 27 soil cores. the proportion of p. engelmannii to p. contorta ectomyco ... | 2000 | 11055953 |
| exposure to dust, resin acids, and monoterpenes in softwood lumber mills. | a study to assess exposure to potential respiratory hazards in a large lumber mill processing spruce (picea engelmannii and glauca), pine (pinus contorta), and fir (abies lasiocarpa) used a random sampling strategy to assess exposures for all jobs in the sawmill, planer mills, and yard. personal samples for inhalable particulate were collected to measure exposure to dust and resin acids (abietic acid and pimaric acid). to estimate wood dust exposure, rather than overall dust, the resin acid cont ... | 2000 | 10976682 |
| molecular evolution of cdc2 pseudogenes in spruce (picea). | the p34cdc2 protein and other cyclin-dependent protein kinases (cdk) are important regulators of eukaryotic cell cycle progression. we have previously cloned a functional cdc2 gene from picea abies and found it to be part of a family of related sequences, largely consisting of pseudogenes. we now report on the isolation of partial cdc2 pseudogenes from picea engelmannii and picea sitchensis, as well as partial functional cdc2 sequences from p. engelmannii, p. sitchensis and pinus contorta. a hig ... | 1998 | 9526509 |
| heterotrophic activity and biodegradation of labile and refractory compounds by groundwater and stream microbial populations. | the bacteriology and heterotrophic activity of a stream and of nearby groundwater in marmot basin, alberta, canada, were studied. acridine orange direct counts indicated that bacterial populations in the groundwater were greater than in the stream. bacteria that were isolated from the groundwater were similar to species associated with soils. utilization of labile dissolved organic material as measured by the heterotrophic potential technique with glutamic acid, phenylalanine, and glycolic acid ... | 1982 | 7125651 |
| engelmann spruce site index models: a comparison of model functions and parameterizations. | engelmann spruce (picea engelmannii parry ex engelm.) is a high-elevation species found in western canada and western usa. as this species becomes increasingly targeted for harvesting, better height growth information is required for good management of this species. this project was initiated to fill this need. the objective of the project was threefold: develop a site index model for engelmann spruce; compare the fits and modelling and application issues between three model formulations and fou ... | 2015 | 25853472 |
| fire severity unaffected by spruce beetle outbreak in spruce-fir forests in southwestern colorado. | 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 ... | 2016 | 27411244 |
| multiscale habitat relationships of snowshoe hares (lepus americanus) in the mixed conifer landscape of the northern rockies, usa: cross-scale effects of horizontal cover with implications for forest management. | snowshoe hares (lepus americanus) are an ecologically important herbivore because they modify vegetation through browsing and serve as a prey resource for multiple predators. we implemented a multiscale approach to characterize habitat relationships for snowshoe hares across the mixed conifer landscape of the northern rocky mountains, usa. our objectives were to (1) assess the relationship between horizontal cover and snowshoe hares, (2) estimate how forest metrics vary across the gradient of sn ... | 2017 | 28070281 |
| epiphytic lichen diversity on dead and dying conifers under different levels of atmospheric pollution. | based on literature data, epiphytic lichen abundance was comparably studied in montane woodlands on healthy versus dead or dying conifers of europe and north america in areas with different levels of atmospheric pollution. study sites comprised picea abies forests in the harz mountains and in the northern alps, germany, picea rubens-abies balsamea forests on whiteface mountain, adirondacks, new york, u.s.a. and picea engelmannii-abies lasiocarpa forests in the salish mountains, montana, u.s.a. d ... | 2005 | 15701398 |
| polyamine biosynthesis during somatic embryogenesis in interior spruce (picea glauca x picea engelmannii complex). | putrescine, spermidine, and spermine levels during somatic embryogenesis of interior spruce (picea glauca x picea engelmannii complex) were quantified on abscisic acid supplemented growth medium putrescine and spermidine levels increased two-fold coinciding with maturation of the early somatic embryos to globular embryos. polyclonal antibodies raised against escherichia coli arginine decarboxylase (adc) and ornithine decarboxylase (odc), following affinity purification specifically recognized sp ... | 1996 | 24178460 |
| pinus flexilis and picea engelmannii share a simple and consistent needle endophyte microbiota with a potential role in nitrogen fixation. | conifers predominantly occur on soils or in climates that are suboptimal for plant growth. this is generally attributed to symbioses with mycorrhizal fungi and to conifer adaptations, but recent experiments suggest that aboveground endophytic bacteria in conifers fix nitrogen (n) and affect host shoot tissue growth. because most bacteria cannot be grown in the laboratory very little is known about conifer-endophyte associations in the wild. pinus flexilis (limber pine) and picea engelmannii (eng ... | 2014 | 25071746 |
| weather and climate controls over the seasonal carbon isotope dynamics of sugars from subalpine forest trees. | we examined the environmental variables that influence the delta(13)c value of needle and phloem sugars in trees in a subalpine forest. we collected sugars from pinus contorta, picea engelmannii and abies lasiocarpa from 2006 to 2008. phloem and needle sugars were enriched in (13)c during the autumn, winter and early spring, but depleted during the growing season. we hypothesized that the late-winter and early-spring (13)c enrichment was due to the mobilization of carbon assimilated the previous ... | 2010 | 19843259 |
| spray deposition from ground-based applications of carbaryl to protect individual trees from bark beetle attack. | bark beetles (coleoptera: curculionidae, scolytinae) are recognized as the most important tree mortality agent in western coniferous forests. a common method of protecting trees from bark beetle attack is to saturate the tree bole with carbaryl (1-naphthyl methylcarbamate) using a hydraulic sprayer. in this study, we evaluate the amount of carbaryl drift (ground deposition) occurring at four distances from the tree bole (7.6, 15.2, 22.9, and 38.1 m) during conventional spray applications for pro ... | 2008 | 18453436 |
| controls of growth phenology vary in seedlings of three, co-occurring ecologically distinct northern conifers. | the objective of this study was to investigate the effects of temperature and seed-source elevation on height-growth phenology of three co-occurring and ecologically distinct northern conifers (pinus contorta dougl. ex loud. var. latifolia (lodgepole pine), picea glauca (moench) voss x picea engelmannii parry ex engelm. (interior spruce) and abies lasiocarpa (hook.) nutt. (subalpine fir)). seed from populations of the three indigenous and co-occurring species was collected across an elevational ... | 2007 | 17472945 |
| evaluation of season, temperature, and water stress effects on stomata using a leaf conductance model. | a model was developed earlier describing conductance for three conifers (picea engelmannii parry ex engelm., abies lasiocarpa [hook.] nutt., and pinus contorta var. latifolia engelm.) and one hardwood (populus tremuloides michx.) using only two terms, photosynthetic photon flux density (ppfd) and absolute humidity difference from leaf to air (dah). using residual analysis techniques (actual minus estimated conductance), it was determined that no seasonal or temperature effects existed that were ... | 1982 | 16662337 |
| leaf conductance as a function of photosynthetic photon flux density and absolute humidity difference from leaf to air. | for an entire season of stomatal activity, leaf or needle conductance was observed on four species, each in a different genus: engelmann spruce (picea engelmannii parry ex engelm.), subalpine fir (abies lasiocarpa [hook.] nutt.), lodgepole pine (pinus contorta var. latifolia engelm.), and aspen (populus tremuloides michx.). conductance in the natural environment was described for all species by photosynthetic photon flux density (ppfd) and absolute humidity difference from leaf to air (dah), as ... | 1982 | 16662336 |
| physiographic, stand, and environmental effects on individual tree growth and growth efficiency in subalpine forests. | annual volume growth of subalpine trees in the central rocky mountains was studied in relation to site and stand conditions. growth of individual trees was most strongly influenced by estimated potential absorbed radiation, which varied with physiographic conditions and tree leaf area. growth efficiency was estimated by the ratio of annual volume growth to potential radiation absorption by the crown. growth efficiency was higher in young lodgepole pine (pinus contorta var. latifolia engelm.) tha ... | 1986 | 14975841 |
| pollen management for intensive seed orchard production. | artificially increasing pollen supply (supplemental mass pollination (smp)) to conifer seed orchards has the potential to increase seed yields and improve the genetic worth of seed crops that would otherwise suffer from the detrimental effects of pollen contamination and unbalanced paternal contribution. however, success rates, measured as the proportion of seed fertilized by smp, have been low. this review examines the concepts underlying smp and presents data for two smp field trials with doug ... | 1995 | 14965935 |
| sapling leaf trait responses to light, tree height and soil nutrients for three conifer species of contrasting shade tolerance. | we developed models to describe the responses of four commonly examined leaf traits (mass per area, weight, area and nitrogen (n) concentration) to gradients of light, soil nutrients and tree height in three conifer species of contrasting shade tolerance. our observational dataset from the sub-boreal spruce forests of british columbia included subalpine fir (abies lasioscarpa [hook.] nutt; high shade tolerance), interior spruce (picea glauca × picea engelmannii [moench] voss; intermediate shade ... | 2014 | 25422385 |
| negative feedbacks on bark beetle outbreaks: widespread and severe spruce beetle infestation restricts subsequent infestation. | 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) i ... | 2015 | 26000906 |
| carbon isotopic composition of forest soil respiration in the decade following bark beetle and stem girdling disturbances in the rocky mountains. | bark beetle outbreaks are widespread in western north american forests, reducing primary productivity and transpiration, leading to forest mortality across large areas and altering ecosystem carbon cycling. here the carbon isotope composition (δ(13) c) of soil respiration (δj ) was monitored in the decade after disturbance for forests affected naturally by mountain pine beetle infestation and artificially by stem girdling. the seasonal mean δj changed along both chronosequences. we found (a) enr ... | 2016 | 26824577 |
| saitoella coloradoensis sp. nov., a new species of the ascomycota, subphylum taphrinomycotina. | saitoella coloradoensis sp. nov. (nrrl yb-2330, cbs 12360, type strain, mycobank accession number 563858) is described. this new member of the phylum ascomycota, subphylum taphrinomycotina was isolated from insect frass occurring in an engelmann spruce (picea engelmannii) that was growing in colorado, usa. multigene sequence analysis showed that s. coloradoensis is distinct from saitoella complicata, the only other known species of saitoella. the two species may be separated phenotypically from ... | 2012 | 22246589 |
| phylogeography of spruce beetles (dendroctonus rufipennis kirby) (curculionidae: scolytinae) in north america. | 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 new ... | 2007 | 17561913 |
| post-fire spatial patterns of soil nitrogen mineralization and microbial abundance. | stand-replacing fires influence soil nitrogen availability and microbial community composition, which may in turn mediate post-fire successional dynamics and nutrient cycling. however, fires create patchiness at both local and landscape scales and do not result in consistent patterns of ecological dynamics. the objectives of this study were to (1) quantify the spatial structure of microbial communities in forest stands recently affected by stand-replacing fire and (2) determine whether microbial ... | 2012 | 23226324 |
| abiotic factors limiting photosynthesis in abies lasiocarpa and picea engelmannii seedlings below and above the alpine timberline. | most research on the occurrence and stability of alpine timberlines has focused on correlations between adult tree growth and mean temperatures rather than on specific mechanisms. timberline migration to higher altitude is dependent on new seedling establishment in the tree-line ecotone; however, reductions in photosynthetic carbon gain in establishing seedlings have previously been interpreted solely in terms of decreased seedling survival. our objective was to evaluate the impact of abiotic fa ... | 2004 | 14757577 |
| dependence of winter water relations of mature high-elevation picea engelmannii and abies lasiocarpa on summer climate. | water relations of engelmann spruce (picea engelmannii parry) and subalpine fir (abies lasiocarpa (hook.) nutt.) trees growing at an elevation of 3230 m on mt. evans, colorado, usa, were studied during the winters of 1995-1996 and 1996-1997. during both winters, current-year and 1-year-old shoots were collected weekly and their relative water contents (rwc) determined. measured meteorological parameters were used in a conifer winter water relations model, winwat, to simulate changes in shoot rwc ... | 2000 | 11269959 |
| 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 |
| influence of krummholz mat microclimate on needle physiology and survival. | microclimate and photosynthesis of krummholz mat growth forms of picea engelmanii (parry) and abies lasiocarpa [hook.] nutt. were investigated to determine structural features which may aid survival in alpine environments. the structure of krummholz mats was described in terms of the vertical distribution of leaf area index and leaf area density, which exceeded 50 m(-1) (based on total leaf surface area) near the canopy surface and approached zero below 30 cm from the surface in both species. ph ... | 1987 | 28311409 |
| deep undercooling of tissue water and winter hardiness limitations in timberline flora. | deep undercooled tissue water, which froze near -40 c, was found in winter collected stem and leaf tissue of the dominant timberline tree species of the colorado rocky mountains, engelmann spruce (picea engelmannii (parry) engelm.) and subalpine fir (abies lasiocarpa (hook.) nutt.), and in numerous other woody species in and below the subalpine vegetation zone. previous work on numerous woody plants indicates that deep undercooling in xylem makes probable a -40 c winter hardiness limit in stem t ... | 1981 | 16661852 |
| structural scaling of light interception efficiency in picea engelmannii and abies lasiocarpa. | sunlight interception efficiency was compared at the leaf, shoot, branch and crown levels for picea engelmannii (parry) and abies lasiocarpa ((hook.) nutt.), dominant tree species of the central rocky mountains, usa. the ratio of silhouette to total leaf area (star) was used to quantify the efficiency of direct-beam sunlight interception at each structural scale. total mean reductions in star from the leaf to the crown level were 0.39 to 0.06 in p. engelmannii and 0.46 to 0.02 in a. lasiocarpa. ... | 1994 | 14967624 |
| 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 |
| nitrogen uptake and turnover in riparian woody vegetation. | the nutrient balance of streams and adjacent riparian ecosystems may be modified by the elimination of anadromous fish runs and perhaps by forest fertilization. to better understand nitrogen (n) dynamics within stream and riparian ecosystems we fertilized two streams and their adjacent riparian corridors in central idaho. on each stream two nitrogen doses were applied to a swathe approximately 35 m wide centered on the stream. the fertilizer n was enriched in 15n to 18 per thousand. this enrichm ... | 2004 | 15133732 |