Publications

effect of elemental sulphur on the vegetation of a lodgepole pine stand.	shrub and herb cover decreased 98% and diversity 76% after particulate elemental sulphur was deposited in a pinus contorta loudon var. latifolia engelm. forest in west-central alberta, canada. decreases were measured over four years and, initially, were greater for the herbs than they were for the shrubs. the decline in the herbs occurred one year before decreases in half the shrub species. the dramatic decline of the vegetation appeared related to the changes in the soil chemistry of the surfac ...	1988	15092632
young's modulus of sections of living branches and tree trunks.	young's modulus along the grain (elasticity, e) was measured on 10 sections of branches and three tree trunks, with bark, of picea sitchensis (bong.) carr., pinus contorta dougl. ex loud., larix decidua mill. and betula pendula roth. syn. verrucosa ehrh. the sections were simply supported and corrections were made for taper and deflection due to shear. the e values for trunks were at the lower end of the range reported for green timber (2.4-7.5 gpa), and those for branches were still lower (0.7- ...	1987	14975919
biochemistry of oleoresinosis : monoterpene and diterpene biosynthesis in lodgepole pine saplings infected with ceratocystis clavigera or treated with carbohydrate elicitors.	elevated levels of monoterpenes and diterpene resin acids are produced in the stems of lodgepole pine (pinus contorta var latifolia) saplings when wounded and inoculated with the blue-stain fungus ceratocystis clavigera or when wounded and treated with a pectic fragment from tomato leaves (piif) or a fungal cell wall fragment (chitosan). this induced defensive response (hyperoleoresinosis) is the result of a transient rise in the ability to biosynthesize cyclic monoterpenes and diterpene resin a ...	1987	16665815
investigations on the nature of the auxin-wave in the cambial region of pine stems : validation of iaa as the auxin component by the avena coleoptile curvature assay and by gas chromatography-mass spectrometry-selected ion monitoring.	the major auxin of scots pine (pinus silvestris l.) which is transported basipetally into agar strips from the cambial region of the stem was quantified by the went avena coleoptile curvature assay before and after reversed phase c(18) high performance liquid chromatography (hplc), and then identified by full spectrum gas chromatography-mass spectrometry (gc-ms) as indole-3-acetic acid (iaa). the iaa was subsequently quantified by gc-ms-selected ion monitoring (sim) using an internal standard of ...	1987	16665387
linkage disequilibrium between allozymes in natural populations of lodgepole pine.	pairwise linkage disequilibrium values (d) were estimated for 14 allozyme loci in two natural populations of lodgepole pine (pinus contorta ssp. latifolia). maternal multilocus genotypes were inferred from samples of (haploid) megagametophytic seed-endosperms. coupling/repulsion double heterozygotes were distinguished for closely linked pairs of loci. assays of seven of the loci in seed embryos allowed estimates of d for these loci in the outcross pollen pool (estimates of outcrossing rates indi ...	1987	17246370
chloroplast dna polymorphisms in lodgepole and jack pines and their hybrids.	samples taken from throughout the ranges of distribution of lodgepole pine (pinus contorta dougl. ex. loud.) and jack pine (pinus banksiana lamb.) were assayed for sal i and sst i chloroplast dna restriction fragment variation. although the chloroplast genome is often regarded as highly conserved, at least 2 distinct sal i and 13 distinct sst i restriction fragment banding patterns occur in these closely related species. none of the chloroplast dna restriction fragment banding patterns observed ...	1987	3470779
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
stomatal responses to humidity in selected conifers.	stomatal response to changes in leaf-to-air water vapor pressure difference (d) was studied in needles of the current year's shoot of three-year-old seedlings of picea sitchensis (bong.) carr., pinus contorta dougl. ex loud., larix x eurolepis henry, and pinus sylvestris l. both eight-week- and ten-month-old shoots of p. sylvestris were studied. stomata of all the species responded by closing to some degree as d was increased over the range 0.4-2.0 kpa. ten-month-old shoots of p. sylvestris show ...	1986	14975844
a dynamic model for studying flow of water in single trees.	flow of water in a single tree was modeled in terms of the darcy equation using a catena of four compartments: root, stem (further divided into discs), branches and leaves. within each compartment or disc, water content was related to both water potential and conductivity of the xylem tissue using power or logarithmic functions, thus introducing both capacitance and variable resistance to flow in the model. transpiration from the leaves to the atmosphere was used as the upper boundary to the mod ...	1986	14975885
sex-specific production of ipsdienol and myrcenol bydendroctonus ponderosae (coleoptera: scolytidae) exposed to myrcene vapors.	male mountain pine beetles,dendroctonus ponderosae hopkins, produced ipsdienol [97.0% ± 0.3s-(+)] and myrcenol (90.3% ± 4.0e) when exposed to myrcene vapors. females which were exposed to myrcene vapors did not produce any ipsdienol, but did produce low levels of myrcenol (98.0% ± 0.7e). neither sex produced detectable levels of ipsdienol or myrcenol when fed for 24 hr on lodgepole pine,pinus contorta var.latifolia engelmann. the sex-specific conversion of myrcene to ipsdienol and myrcenol sugge ...	1986	24305835
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
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
gas chromatography-mass spectroscopy identification of 1-aminocyclopropane-1-carboxylic acid in compressionwood vascular cambium of pinus contorta dougl.	following cation and anion exchange chromatography, 1-aminocyclopropane-1-carboxylic acid (acc) was converted to the 2,4-dinitrophenyl derivative and then purified by high-performance liquid chromatography (hplc). after three hplc steps, endogenous acc was identified by gcms in the vascular cambium on the lower side of pinus contorta dougl. ssp. latifolia branches in association with compressionwood differentiation, but acc was not detected in the opposite wood cambial region on the upper sides ...	1983	16662843
the role of plant hormones in higher plant cellular differentiation. ii. experiments with the vascular cambium, and sclereid and tracheid differentiation in the pine, pinus contorta.	in sterile-cultured explants of stems of the pine pinus contorta dougl., fusiform cambial cells differentiated entirely into axial parenchyma cells when exogenous indol-3yl-acetic acid (iaa) was omitted. the normal appearance of the cambial zone was maintained when iaa was included in the medium. the iaa-maintained stability of cambial structure suggests physiological rather than epigenetic control over vascular cambium structure. iaa was essential for the occurrence of callus growth in stem exp ...	1983	6223902
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
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
the fate of fenitrothion in a stream environment and its effect on the fauna, following aerial spraying of a scottish forest.	in order to control an infestation of pine beauty moth (panolis flammea schiff.) fenitrothion was applied at a rate of 300 g ha-1 to a forest plantation consisting primarily of lodgepole pine (pinus contorta loud.) and sitka spruce (picea sitchensis carriere) using the ultra-low volume spraying technique. the concentration of fenitrothion in the forest stream rose to a maximum of 18 micrograms l-1 within the treated area an hour after spraying, but fell to 0.5 microgram l-1 after 24 hs. there wa ...	1981	7280656
thermal ir exitance model of a plant canopy.	a thermal ir exitance model of a plant canopy based on a mathematical abstraction of three horizontal layers of vegetation was developed. canopy geometry within each layer is quantitatively described by the foliage and branch orientation distributions and number density. given this geometric information for each layer and the driving meteorological variables, a system of energy budget equations was determined and solved for average layer temperatures. these estimated layer temperatures, together ...	1981	20309167
simulation of solar radiation absorption in vegetation canopies.	a solar radiation canopy absorption model, including multiple scattering effects, was developed and tested for a lodgepole pine (pinus contorta) canopy. reflectance above the canopy, spectral transmittance to the ground layer, and geometric and spectral measurements of canopy elements were made. relatively large differentials occurred in spectral absorption by canopy layers, especially in the photosynthetically active region, as a function of solar zenith angle. in addition, the proportion of to ...	1980	20234510
importance of aerodynamic resistance to water use efficiency in three conifers under field conditions.	the quantitative importance of aerodynamic resistance to h(2)o vapor and co(2) exchange was determined for shoots from saplings of three conifers (abies lasiocarpa [hook] nutt., pinus contorta dougl., juniperus communis l.) under natural conditions in the field. a combination of relatively low stomatal resistances (<300 seconds per centimeter) and low wind speeds (<30 centimeters per second) led to substantial contributions of the aerodynamic resistance (r(wv) (a)) to water use efficiency (wue = ...	1980	16661128
soil temperature influences on root resistance of pinus contorta seedlings.	the influence of low temperature in the root zone on water uptake in lodgepole pine (pinus contorta dougl. ex loud.) was studied under laboratory conditions. to remove soil hydraulic influences, two-year-old seedlings were transferred to solution cultures and maintained in temperature controlled water baths. short term measurements of leaf conductance, leaf water potential and tritiated water movement were taken at root temperatures from 22 c down to 0 c. root resistance was calculated to be 67% ...	1980	16661254
characterization of the bacterial flora associated with root systems of pinus contorta var. latifolia.	root systems of young and mature lodgepole pine (pinus contorta dougl. var. latifolia englem.) were removed from forest stands and the associated aerobic bacterial flora isolated. characterization of rhizoplane and control soil isolates from these tree root systems demonstrated differences from that reported for agricultural crops. ammonifying, proteolytic, and amylolytic organisms were proportionately reduced within the rhizoplane. the rhizoplane organisms grew more slowly than the control soil ...	1978	747813
quantitative assessment of the bacterial rhizosphere flora of pinus contorta var. latifolia.	the bacterial flora associated with root systems of young and mature lodgepole pine was investigated by sampling forest-grown trees. counts were performed and expressed on a surface-area basis to give a more realistic comparison of organism density or activity within the control soil, rhizosphere soil, and rhizoplane. on this basis, densities increased by an order of 10(4)- to 10(6)-fold from control soil to rhizoplane, with the degree of stimulation being inversely related to root radius.	1975	1220866
pollen sequence from late quaternary sediments in yellowstone park.	a radiocarbon-dated pollen diagram from a depression near the end of the southeast arm of yellowstone lake, wyoming, records the vegetation sequence from the retreat of late wisconsin (pinedale) ice to the present time. the tundra picea-abies-pinus albicaulis (spruce-fir-whitebark pine) parkland vegetation inferred during late glacial time changed rapidly to a pinus contorta (lodgepole pine) forest shortly before 11,550 carbon-14 years ago, suggesting a warming trend at that time. the pinus cont ...	1970	17731592