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The relationship between forest stand composition in southern interior British Columbia and fluorescent pseudomonad bacteria populations was investigated using seedling bioassays. The objectives of this study were to (i) compare the relative population sizes of fluorescent pseudomonads baited from soils in pure paper birch (Betula papyrifera Marsh.), pure Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and mixed stands of the two species and (ii) determine if fluorescent pseudomonads from these soils have inhibitory effects against the root pathogen Armillaria ostoyae (Romagn.) Herink in vitro. Soil from birch stands supported four times more pseudomonads on seedling baits than soil from Douglas-fir stands, with the mixed stands intermediate. Soil from young stands yielded twice as many rhizosphere pseudomonads as soil from mature stands. Pseudomonad population size was positively correlated with percent cover and density of birch, and negatively correlated with basal area of Douglas-fir, percent cover of Douglas-fir, and carbon/nitrogen ratio of the soil. Greater than 50% of the fluorescent isolates reduced radial growth of A. ostoyae by more than 20% and greater than 90% reduced biomass of the fungus in dual culture tests. Cell-free bacterial culture filtrates added to the growth medium also reduced growth of A. ostoyae. This study provides evidence that paper birch provides a more favorable environment for fluorescent pseudomonads than Douglas-fir and suggests a mechanism by which paper birch can positively influence the susceptibility of managed forest stands to Armillaria root disease. [ABSTRACT FROM AUTHOR]

Reports on the measured rates of decomposition at three sites representing the major mixedwood forest types of British Columbia: (i) boreal forests of white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuloides Michx.), (ii) coastal forests of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and red alder (Alnus rubra Bong.), and (iii) a wet interior forest of Douglas-fir, paper birch (Betula papyrifera Marsh.), and lodgepole pine (Pinus contorta Doug. ex Loud.). Mass loss of litter of each species (both pure and in combination with the other species) that was measured in forests of each species to determine (i) if broadleaf litter decomposed faster than needle litter, (ii) if litter decomposed faster in broadleaf or mixedwood forests than in coniferous forests, and (iii) if mixing with broadleaf hastened decomposition of needle litter; Broadleaf litters that decomposed faster than needles during the first year but, thereafter, decomposed more slowly; Litter that tended to decompose faster in the broadleaf forests than in the coniferous forests; No evidence to indicate that the addition of broadleaf litter hastened decomposition of needle litter; Results that indicate that the mixing of needle litter with broadleaf litter is unlikely to hasten decomposition in mixedwood forests of British Columbia.

In 1996 we initiated a study to evaluate several techniques for measuring light under broadleaf canopies. Hourly average photosynthetic photon flux density and percent transmittance were measured 1 m above the ground at four points in each of three canopy densities created by a spacing experiment in a 35-year-old paper birch (Betula papyrifera Marsh.) dominated stand located near Prince George, B.C. At each point, fisheye photographs were taken and LAI-2000 plant canopy analyzer (LAI-2000), spherical densiometer, and competition index (Lorimer'sindex) measurements were made. Percent transmittance measurements onan overcast day (1-h average), transmittance measured over periods of 3 h or longer on a clear day, LAI-2000 diffuse noninterceptance measurements, and gap light index determined from fisheye photographs were strongly correlated with growing season percent transmittance (r2>= 0.96) as was competition index (r2 = 0.928). Concave spherical densiometer measurements and midday percent transmittance measurements on clear days were also well correlated with measured percent transmittance (r2>= 0.89). Estimates of understory light by the LITE model were strongly correlated with growing season percent transmittance. Correlations improved with increasing length of the period simulated (r2 = 0.755 for a point measurement on a clear day; r2 = 0.936 for an entire sunny day;and, r2 = 0.953 for the entire growing season). However, this version of the model underestimated percent transmittance in these spaced birch stands by 34-90%. [ABSTRACT FROM AUTHOR]

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Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

New bedrock mapping completed as part of the Nechako NATMAP Project indicates that the area between Babine and Takla lakes in central British Columbia is underlain by rocks of the Early Permian Asitka, Late Triassic Takla, and Early to Middle Jurassic Hazelton volcanic-arc assemblages of the Stikine Terrane. These are cut by large composite stocks of quartz diorite, granodiorite, and quartz monzonite previously mapped as the Late Triassic to Early Jurassic Topley intrusions. New U/Pb (n = 6) and laser [sup 40] Ar/[sup 39] Ar (n = 10) isotopic age dates reported in this paper suggest there are two distinct ages of plutons: the Topley intrusive suite with isotopic ages between 218 and 193 Ma; and, east of Babine Lake, the new Spike Peak intrusive suite with isotopic ages ranging from 179 to 166 Ma. West of the main plutonic belt is a thick volcanic succession of subaerial, porphyritic andesite flows, volcanic breccias, and rhyolitic ash-flow tuffs that have isotopic ages between 185 and 174 Ma. These rocks are assigned to the Saddle Hill Formation of the Hazelton Group. The plutonic roots of this proximal arc assemblage are most likely the coeval and compositionally similar plutons of the Spike Peak intrusive suite that have been unroofed in the area east of the Takla Fault. Major oxide and trace element data support the interpretation that the Topley and Spike Peak granitic rocks formed in a juvenile volcanic-arc environment and that magmatism is related to melts generated above a long-lived subduction zone of unknown orientation.Une nouvelle cartographie effectuée dans le cadre du projet NATMAP Nechako indique que la région entre les lacs Babine et Takla au centre de la Colombie-Britannique est recouverte de roches des assemblages d'arcs volcaniques du terrane de Stikine, soit Asitka du Permien précoce, Takla du Trias tardif et Hazelton du Jurassique précoce à moyen. Ces assemblages sont recoupés par des petits massifs intrusifs composites de diorite quartzique, de granodiorite et de monzonite quartzique qui avaient auparavant été cartographiés en tant que les intrusions Topley, du Trias tardif au Jurassique précoce. De nouvelles datations U-Pb (n = 6) et isotopes laser [sup 40] Ar/[sup 39] Ar (n = 10) présentées dans cet article suggèrent deux âges distincts de plutons, soit la suite intrusive de Topley avec des âges isotopiques entre 218 et 193 Ma et, à l'est du lac Babine, la nouvelle suite intrusive de Spike Peak dont les âges isotopiques varient de 179 à 166 Ma. À l'ouest de la ceinture plutonique principale se trouve une séquence volcanique épaisse d'écoulements subaériens d'andésite porphyrique, des brèches volcanique et des tufs d'écoulement de cendre rhyolitique dont les âges isotopiques varient entre 185 et 174 Ma. Ces roches sont assignées à la Formation de Saddle Hill du Groupe Hazelton. Les racines plutoniques de cet assemblage d'arc proximal sont fort probablement les plutons contemporains et à composition similaire de la suite intrusive de Spike Peak qui ont été décapés dans la région à l'est de la faille de Takla. Les données sur les principaux oxydes et les éléments traces corroborent l'interprétation que les roches granitiques de Topley et de Spike Peak se sont formées dans un environnement d'arc volcanique juvénile et que le magmatisme est relié aux fusions qui se sont produites au-dessus d'une ligne de subduction de longue durée mais dont l'orientation est inconnue.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

New U/Pb and [sup 40] Ar/[sup 39] Ar isotopic dating in the Babine porphyry copper district of central British Columbia documents three distinct magmatic events at 107–104, 85–78, and 54–50 Ma. The earliest event involved emplacement of rhyolite domes into submarine volcanic rocks of the Rocky Ridge Formation. The rhyolite domes and related dacitic to basaltic volcanic rocks gave a U–Pb age of 107.9 ± 0.2 Ma and an [sup 40] Ar/[sup 39] Ar age of 104.8 ± 1.2 Ma. The rhyolites, which were previously mapped as Eocene, are reinterpreted to be part of a previously unrecognized mid-Cretaceous cauldron subsidence complex. The regionally extensive Late Cretaceous magmatic event is also recognized in the Babine district and is represented by [sup 40] Ar/[sup 39] Ar ages of 85.2 ± 2.8 and 78.3 ± 0.8 Ma on two Bulkley intrusions, one of which has associated porphyry copper mineralization. The final magmatic event is the most widespread and involved emplacement of the Babine intrusions and formation of numerous porphyry copper deposits including the Bell and Granisle past producers. Twenty-one new [sup 40] Ar/[sup 39] Ar isotopic ages for these intrusions and coeval andesites of the Newman Formation have a narrow range from 53.6 ± 0.9 to 49.9 ± 0.6 Ma, whereas previous K–Ar isotopic dating had a possible range of 15 Ma. The mid-Cretaceous, Late Cretaceous, and Eocene magmatic suites in the Babine district are interpreted to be part of a long-lived volcano-plutonic complex that was the site of periodic magmatism and porphyry copper mineralization over a 60 Ma time period. This complex may have evolved within a zone of extension (pull-apart basins) situated between dextral strike-slip faults that were active during periods of rapid oblique plate convergence.De nouvelles datations U–Pb et isotopiques [sup 40] Ar/[sup 39] Ar dans le district de cuivre porphyrique Babine, du centre de la Colombie-Britannique, documentent trois événements magmatiques distincts à 107–104 Ma, 85–78 Ma et 54–50 Ma. L'événement le plus précoce impliquait la mise en place de dômes de rhyolite dans les roches volcaniques sous-marines de la Formation de Rocky Ridge. Les dômes de rhyolite et les roches volcaniques apparentées dacitiques à basaltiques ont donné un âge U–Pb de 107,9 ± 0,2 Ma et un âge [sup 40] Ar/[sup 39] Ar de 104,8 ± 1,2 Ma. Les rhyolites, antérieurement cartographiées comme datant de l'Éocène, sont réinterprétées comme faisant partie d'un complexe de cuvettes d'effondrement auparavant non reconnues et qui dateraient du Crétacé moyen. Le magmatisme extensif régional du Crétacé tardif est aussi reconnu dans le district de Babine et il est représenté par des âges [sup 40] Ar/[sup 39] Ar de 85,2 ± 2,8 et 78,3 ± 0,8 Ma sur deux intrusions Bulkley, dont l'une présente une minéralisation associée de cuivre porphyrique. L'événement magmatique final est le plus répandu et il comprend la mise en place des intrusions Babine et la formation de nombreux gisements de cuivre porphyrique incluant les anciens gisements productifs de Bell et de Granisle. Vingt et un nouveaux âges [sup 40] Ar/[sup 39] Ar pour ces intrusions et des andésites contemporaines de la Formation Newman ont une plage étroite de 53,6 ± 0,9 à 49,9 ± 0,6 alors que des datations antérieures d'isotopes K–Ar avaient une plage de 15 Ma. Les suites magmatiques du Crétacé moyen, du Crétacé tardif et de l'Éocène dans le district de Babine sont interprétées comme faisant partie d'un complexe volcano-plutonique de longue durée où s'est produit du magmatisme périodique et de la minéralisation en cuivre porphyrique durant une période de 60 Ma. Ce complexe peut avoir évolué à l'intérieur d'une zone d'extension (basins d'extension) située entre des failles dextres à décrochement horizontal qui étaient actives durant les périodes de convergence rapide et oblique des plaques.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Twenty-six years ago, in response to regionally devastating fisheries collapses in Canada, Hutchings et al. asked "Is scientific inquiry incompatible with government information control?" Now, a quarter-century later, we review how government science advice continues to be influenced by non-science interests, particularly those with a financial stake in the outcome of the advice. We use the example of salmon aquaculture in British Columbia, Canada, to demonstrate how science advice from Fisheries and Oceans Canada (DFO) can fail to be impartial, evidence-based, transparent, and independently reviewed—four widely implemented standards of robust science advice. Consequently, DFO's policies are not always supported by the best available science. These observations are particularly important in the context of DFO having struggled to sustainably manage Canada's marine resources, creating socio-economic uncertainty and putting the country's international reputation at risk as it lags behind its peers. We conclude by reiterating Hutchings et al.'s unheeded recommendation for a truly independent fisheries-science advisory body in Canada to be enshrined in the decision-making process. [ABSTRACT FROM AUTHOR]

Microplastics are a global contaminant of concern, but we have little information on the characteristics and bioavailability of these pollutants in western Canadian lakes. Here, we quantify and characterize microplastics in subsurface water and zooplankton from eight lakes in BC, Canada. By sampling water and zooplankton, we provide insight into the fraction of microplastics entering the food web. We found 0.607 ± 0.153 microplastics per litre in subsurface water, 0.01 ± 0.011 microplastics per copepod, and 0.02 ± 0.014 microplastics per Daphnia. Microplastic pollution was similar in all lakes sampled and showed no relationship with local population density. Fibers were the dominant morphology observed in all lakes, and Raman spectroscopy identified polyester as the dominant polymer found both in lakes and within zooplankton. Zooplankton generally ingested microplastics that were shorter than their body length and that fell on the smaller end of the range of available microplastics. The prominence of polyester fibers and PET films and fragments suggests that the likely sources of microplastics to these lakes are recreational activities and atmospheric deposition. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper examines suspended sediment concentration and stream discharge during freshet in three small sub-boreal forest streams (<1.5 m in width) in the central interior of British Columbia for 1 year prior to (1996) and for 5 years following forest harvesting (1997-2001). Harvesting prescriptions in a 20-m strip beside one stream required complete removal of merchantable timber (>15 cm diameter at breast height (DBH) for pine and >20 cm for spruce), while all stems <30 cm DBH were retained beside a second stream. A third stream remained unharvested as a control. The two riparian treatments were prescribed to test the efficacy of current British Columbia legislation that allows for varying amounts of riparian retention as best management practices for the management of windthrow. Both treated watersheds were clear-cut harvested (approximately 55% removal) in January 1997, and in the following year, temporary access roads were deactivated, including two stream crossings in the low-retention watershed. An increase in peak snowmelt and total freshet discharge was first noted in the second spring following harvest in both treatments and remained above predicted in all subsequent years. Suspended sediment also increased during freshet following harvest but returned to levels at or below preharvest predictions within 3 years or less in the high-retention watershed. [ABSTRACT FROM AUTHOR]

Presents a study that measured and described in detail and sampled for conodont microfossils of the lower to middle Devonian deserter formation, Road River Group in northeastern British Columbia. Regional and economic geology of the area; Lithostratigraphy of the Road River Group; Distribution of conodont elements recovered from Ospika River section.

The paper presents the results of laboratory triaxial compression tests to study the stiffness of very loose Fraser River sands. The stiffness has been shown to be very dependent on the time of confinement prior to shearing and the stress ratio at which the sample is aged. Higher stress ratios resulted in very low initial moduli with no ageing, but the moduli increased by several hundred percent during the first 1000 min of ageing. For ageing at a stress ratio of 1.0 (i.e., isotropic ageing), the initial moduli were higher than those for ageing at high stress ratios, but the stiffness increased by only about 60% during the first 1000 min of ageing. The rate of stiffness increase was approximately linear with the logarithm of time up to ageing times of 10 000 min (>1 week). Ageing at any stress ratio resulted in reduced contractive volumetric strain during subsequent shearing, reflecting a change in soil structure during ageing. The dℇ[sub v] /dℇ[sub a] ratio under triaxial compression loading decreased as the ageing stress ratio increased. The results suggest that close attention must be paid to the age of laboratory samples prepared to study the stress–strain response of sands at strains up to about 0.1%, particularly in studies on loose sand.Key words: sands, ageing, creep, modulus.Cet article présente les résultats d'un programme d'essais en laboratoire pour étudier la rigidité de sables très lâches du fleuve Fraser au moyen d'essais de compression triaxiale. On a montré que la rigidité était très dépendante du temps de confinement antérieur au cisaillement et du rapport des contraintes sous lequel l'échantillon a vieilli. Des rapports de contraintes plus élevés ont donné des modules initiaux très faibles sans vieillissement, mais les modules ont augmenté de plusieurs 100 % au cours des mille premières minutes de vieillissement. Sous un vieillissement isotrope, les modules initiaux étaient plus élevés que pour des rapports de contraintes plus élevés mais la rigidité a augmenté de seulement environ 60 % durant les 1000 premières minutes de vieillissement. La vitesse d'augmentation de la rigidité était approximativement linéaire en fonction du logarithme du temps jusqu'à des temps de vieillissement de 10 000 minutes (>1 semaine). Le vieillissement sous n'importe quel rapport de contraintes a donné des déformations volumétriques de contraction réduites durant le cisaillement subséquent, ce qui indiquait un changement dans la structure du sol durant le vieillissement. Le rapport dℇ[sub v] /dℇ[sub a] sous chargement triaxial en compression a diminué lorsque le rapport de contraintes de vieillissement augmentait. Les résultats suggèrent que l'on doit porter un attention particulière à l'âge des échantillons préparés en laboratoire pour étudier la réponse contrainte-déformation des sables jusqu'à des déformations de 0,1 %, particulièrement dans les études sur le sable lâche.Mots clés : sables, vieillissement, fluage, module.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Irrigated agriculture in semi-arid regions is expected to increase in the future, which puts greater demands on scarce water resources. Sustainable irrigation strategies in semi-arid regions will support agricultural resilience to climatic change. The response of "Sweetheart"/Mazzard sweet cherry trees (Prunus avium L.) to postharvest deficit irrigation (PDI), as a water conservation method, was studied over three seasons (2019–2022) in the semi-arid Okanagan Valley of British Columbia, at five commercial orchards. The following irrigation treatments were applied; (i) a control of full irrigation, irrigated according to conventional growers' practice at each orchard, (ii) PDI-30: 27%–33% reduction in irrigation volume, after harvest (67%–73% of control), and (iii) PDI-50: 47%–52% reduction in irrigation volume, after harvest (48–53% of control). Spring phenology (the timing of flower bud development, from side green to full bloom), flower bud moisture content and cold hardiness, and fruit yield and quality (before and after cold storage and shelf-life conditions) were assessed to determine if PDI altered fruit development over the subsequent growing season. Neither PDI-30 nor PDI-50 caused changes in the timing of flower bud phenology, cold hardiness or moisture content relative to the control. PDI treatments also had no effect on fruit yield or fruit quality at harvest or after storage and shelf-life conditions. These results suggest PDI could be used to reduce irrigation water use in semi-arid regions, like the Okanagan Valley, without affecting sweet cherry production or fruit quality. [ABSTRACT FROM AUTHOR]

An unusually intense atmospheric river affected the southern coastal region of British Columbia in mid-November 2021. Flooding and several ground failures such as landslides and riverbank erosion caused significant damage and interrupted the main transportation corridors, including major highways and railroads, severing land connectivity between Metro Vancouver and the rest of Canada. In this short note, we summarize and describe slope and riverbank ground failures in the Lower Mainland and connecting corridors to the interior such as the Fraser Canyon and the Coquihalla Valley, with focus on those that produced damage on highways. Field observations are discussed in the context of potential future similar disasters in the region due to more frequent extreme climatic events associated with climate change. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The presence of Watinoceras reesidei Warren, Watinoceras coloradoense (Henderson), Watinoceras thompsonense Cobban, and Mytiloides mytiloides (Mantell) within the Tuskoola sandstone beds of the Vimy Member of the Kaskapau (Blackstone) Formation, places these strata within the lower Turonian stage of the Upper Cretaceous, within the Watinoceras reesidei Zone. International discoveries of Watinoceras in the United States, the Arctic, west Africa, northern Africa, Europe, and Asia, in the past fifty years has allowed the authors, while updating the stratigraphy and taxonomy, to refine correlation of the Tuskoola sandstone, a sandy facies of the "Second White Specks" horizon of Western Canada.La présence de Watinoceras reesidei Warren, Watinoceras coloradoense (Henderson), Watinoceras thompsonense Cobban et Mytiloides mytiloides (Mantell) dans les lits de grès de Tuskoola du membre Vimy de la Formation de Kaskapau (Blackstone), place ces strates à l'étage Turonien inférieur du Crétacé supérieur, à l'intérieur de la zone à Watinoceras reesidei. Des découvertes internationales de Watinoceras aux États-Unis, dans l'Arctique, en Afrique occidentale, en Afrique du Nord, en Europe et en Asie au cours des cinquante dernières années ont permis aux auteurs, tout en mettant à jour la stratigraphie et la taxonomie, de préciser la corrélation du grès de Tuskoola, un faciès gréseux de l'horizon « Second White Specks » de l'Ouest du Canada.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

To investigate the utility of short visits to seabird colonies to gauge nestling growth performance and diet, in four consecutive years from 1995 to 1998, the paper measures the nestling development and diet of rhinoceros auklets or cerorhinca monocerata at three colonies in British Columbia: Seabird Rocks, Triangle Island and SGaang Gwaii (Anthony Island).

A new fauna of fossil marine reptiles is described from the Late Cretaceous Nanaimo Group of Vancouver Island. The fossils are from the Haslam and Pender formations (upper Santonian) near Courtenay, British Columbia, and include elasmosaurid plesiosaurs, turtles, and mosasaurs. This is only the second fauna of Late Cretaceous marine reptiles known from the Pacific Coast, the other being from the Moreno Formation of California (Maastrichtian). The new Nanaimo Group fossils are some 15 million years older than those from the Moreno Formation. However, like the California fauna, there are no polycotylid plesiosaurs, and one of the mosasaurs is a new genus. This reinforces the provinciality of the Pacific faunas and their isolation from contemporaneous faunas in the Western Interior Seaway.Une nouvelle faune de reptiles marins est décrite en provenance du Groupe de Nanaimo (Crétacé tardif) de l'île de Vancouver. Les fossiles proviennent des formations de Haslam et de Pender (Santonien supérieur), près de Courtenay, en Colombie-Britannique et ils comprennent des plésiosaures Elasmosauridae, des tortues et des mosasaures. Cette faune est seulement la deuxième de reptiles marins du Crétacé tardif connue sur la côte du Pacifique, l'autre provenant de la Formation de Moreno (Maastrichtien) en Californie. Les nouveaux fossiles du Groupe de Nanaimo sont quelque 15 millions d'années plus âgés que ceux de la formation de Moreno. Toutefois, tout comme la faune de la Californie, il n'y a pas de plésiosaures Polycotylidae et l'un des mosasaures représente un nouveau genre. Cela donne du poids à l'idée de provincialisme des faunes du Pacifique et leur isolation des faunes contemporaines de la « Western Interior Seaway ».[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The upper Middle Jurassic to Lower Cretaceous Relay Mountain Group is the lower part of the northern Tyaughton–Methow basin, southwestern British Columbia. The Relay Mountain Group consists of ~2700–3400 m of clastic rocks that we subdivide into three formal formations. The Callovian and lower Oxfordian Tyoax Pass Formation is marine shale and sandstone turbidites. The Teepee Mountain Formation consists of upper Oxfordian to Valanginian shallow marine clastic rocks with common Buchia and fluvial and marginal marine facies in the upper part of the unit in the northwest. These rocks overlie the lower formation across an abrupt conformable to disconformable contact. The Hauterivian (and Barremian?) Potato Range Formation consists of clastic rocks that are marine in the southeast, mainly nonmarine to the northwest, and derived from the west. This unit displays an abrupt conformable to disconformable contact with the middle formation and locally rests above the lower formation across an angular unconformity. The Relay Mountain Group and correlative strata of the southeastern Coast Belt form an overlap assemblage above the Bridge River and Cadwallader (including Methow) terranes and link them by late Middle Jurassic time. The early Relay Mountain Group appears to have been a fore-arc basin, possibly along an oblique–convergent margin in the middle unit. The upper unit indicates major changes to a back-arc basin linked to the Ottarasko, and possibly Gambier, arc to the west. This is the oldest probable link (~130 Ma) between the southeastern and southwestern Coast belts.Le Groupe de Relay Mountain (Jurassique moyen au Crétacé inférieur) forme la partie inférieure du bassin Tyaughton–Methow septentrional, dans le sud-ouest de la Colombie-Britannique. Le Groupe de Relay Mountain comprend ~2700–3400 m de roches clastiques que nous subdivisons en trois formations formelles. La Formation de Tyoax Pass, du Callovien et de l'Oxfordien inférieur, est formée de shales marins et de turbidites de grès. La Formation de Teepee Mountain comprend des roches clastiques marines d'eau peu profonde, de l'Oxfordien supérieur au Valanginien, dans lesquelles on retrouve fréquemment Buchia, et des faciès fluviaux et de bordure marine dans la partie supérieure de l'unité au nord-ouest. Ces roches reposent sur la formation inférieure chevauchant un contact abrupt concordant à non concordant. La Formation de Potato Range, du Hauterivien (et Barremien?), comprend des roches clastiques qui sont marines vers le sud-est, surtout non marines vers le nord-ouest et qui proviennent de l'ouest. Cette unité montre un contact abrupt concordant à non concordant avec la formation centrale et, par endroits, repose sur la formation inférieure en discordance angulaire. Le Groupe de Relay Mountain et les strates corrélatives de la ceinture côtière sud-est forment un assemblage de transgression au-dessus des terranes de Bridge River et de Cadwallader (incluant Methow) et les relient au Jurassique moyen tardif. Le Groupe de Relay Mountain initial semble avoir été un bassin d'avant-arc, possiblement le long d'une marge à convergence oblique dans l'unité centrale. L'unité supérieure indique des changements majeurs à un bassin d'arrière-arc relié à l'arc Ottarasko, et possiblement à l'arc Gambier, vers l'ouest. Cela représente le lien probable le plus ancien (~130 Ma) entre les ceintures côtières du sud-est et du sud-ouest.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The Cariboo Mountains, British Columbia, contain an intracontinental dextral strike-slip fault system that crosscuts the regional fold structures. This fault system accounts for a minimum of 120 km and a maximum of 200 km of dextral strike-slip displacement. This probably accommodates some of the motion associated with the southern termination of the Northern Rocky Mountain Trench Fault and is part of a step-over zone between the Northern Rocky Mountain Trench Fault and the Fraser River – Straight Creek fault systems. The Isaac Lake Synclinorium is a kilometre-scale Jurassic fold structure that is bounded by the dextral oblique Isaac Lake and Winder strike-slip faults. These faults are part of the regional strike-slip fault system that is found throughout the Cariboo Mountains. Deformation associated with the strike-slip faults is complex and is partitioned into motion along the faults and into the formation of kilometre-scale folds that are found in areas between the faults. The angular relationship between the strike-slip faults and folds conforms to models developed for dextral strike-slip fault systems with drag on high-friction faults. We interpreted these structures to have formed during a continuous deformation event. Timing constraints indicate that faulting started by the Late Cretaceous and may have had a long and protracted history into the Tertiary.La chaîne Cariboo, en Colombie-Britannique, possède un système intracontinental de failles décrochantes dextres qui recoupe les structures de pli régionales. Ce système de failles est responsable d'un déplacement horizontal dextre d'au moins 120 km et d'au plus 200 km. Il est aussi probablement responsable d'une partie du mouvement associé à l'extrémité sud de la faille du sillon des Rocheuses septentrionales et il fait partie de la zone empiétant sur la faille du sillon des Rocheuses septentrionales et les systèmes de failles Fraser River – Straight Creek. Le synclinorium de Isaac Lake est une structure de pli d'ordre kilométrique, datant du Jurassique; il est limité par les failles décrochantes dextres obliques de Isaac Lake et de Winder. Ces failles font partie du système de failles décrochantes régionales que l'on retrouve à travers toute la chaîne Cariboo. La déformation associée aux failles décrochantes est complexe et elle est répartie en mouvement le long des failles et en formation de plis d'échelle kilométrique qui se retrouvent dans certaines régions entre les failles. La relation angulaire entre les failles décrochantes et les plis est conforme aux modèles développés pour des systèmes de failles décrochantes dextres comportant du frottement pour les failles à coefficient de frottement élevé. Nous croyons que ces structures ont été formées au cours d'un événement de déformation continue. Les contraintes de temps indiquent que les failles ont débuté au Crétacé tardif et qu'elles ont pu avoir une longue histoire qui s'est prolongée jusqu'au Tertiaire.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The character of the Paleozoic basement of Quesnel Terrane and the position of the terrane accretion surface that separates Quesnel and Kootenay terranes from rocks of the ancient North American margin are subjects of debate. To address these problems, detailed mapping and U–Pb geochronologic studies were carried out in the Christina Lake area to define the relationship of the Mollie Creek assemblage, Josh Creek diorite, and Fife diorite to similar lithologies in the Greenwood – Grand Forks and Rossland regions, and to place limits on the ages of regional deformation and local position of the terrane accretion surface. Deformed metasedimentary rocks of the Mollie Creek assemblage may correlate with sedimentary rocks of the Pennsylvanian to Early Triassic Mount Roberts Formation in the Rossland area. The Mollie Creek assemblage is intruded by the foliated Late Triassic Josh Creek diorite. The Josh Creek diorite and Mollie Creek assemblage have been deformed together as a result of phase two deformation, following the intrusion of the Josh Creek diorite in the Late Triassic and prior to the intrusion of the Fife diorite and deposition of the overlying Rossland Group in the Early Jurassic. Based on relative age, structural position, and lithological similarities to other units within Quesnel Terrane, the Mollie Creek assemblage, Josh Creek diorite, and Fife diorite are a part of Quesnel Terrane and lie above the terrane accretion surface in the Christina Lake area. Therefore, Quesnel Terrane does not unconformably overlie basement rocks of known North American affinity in this region.Le caractère du socle paléozoïque du terrane de Quesnel et la position de la surface d'accrétion du terrane qui sépare les terranes de Quesnel et de Kootenay des roches de l'ancienne marge nord-américaine sont sujets à discussion. Afin d'aborder ces problèmes, de la cartographie de détail et des études géochronologiques U–Pb ont été entreprises dans la région du lac Christina afin de définir la relation entre l'assemblage de Mollie Creek, la diorite de Josh Creek, la diorite de Fife et des lithologies similaires dans les régions de Greenwood–Grand Forks et de Rossland et de circonscrire les âges de la déformation régionale ainsi que la position locale de la surface d'accrétion du terrane. Des roches métasédimentaires déformées de l'assemblage de Mollie Creek correspondent peut-être à des roches sédimentaires de la Formation de Mount Roberts (Pennsylvanien à Trias précoce) dans la région de Rossland. La diorite foliée de Josh Creek (Trias tardif) pénètre dans l'assemblage de Mollie Creek. La diorite de Josh Creek et l'assemblage de Mollie Creek ont été déformés ensemble à la suite d'une déformation de phase deux, après l'intrusion de la diorite de Josh Creek au Trias tardif et avant l'intrusion de la diorite de Fife et la déposition du Groupe de Rossland sus-jacent, au Jurassique précoce. Selon les âges relatifs, la position structurale et les similitudes lithologiques aux autres unités à l'intérieur du terrane de Quesnel, l'assemblage de Mollie Creek, la diorite de Josh Creek et la diorite de Fife font partie du terrane de Quesnel et reposent au-dessus de la surface d'accrétion du terrane dans la région du lac Christina. Le terrane de Quesnel ne repose donc pas en discordance sur les roches du socle d'affinité nord-américaine connue dans cette région.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The Spa Creek assemblage is a distinctive thin pericratonic succession that crosses the Okanagan Valley in the hinterland of the southern Cordilleran Orogen in Canada. The succession was ductilely deformed and metamorphosed before deposition of overlying Triassic dark metaclastic strata. A metaconglomerate within the succession, locally composed of more than 90% biotite granite clasts, yielded five fractions of euhedral zircon that define a precise U–Pb upper intercept of 555.6 ± 2.5 Ma, inferred to be the age of a nearby pluton. Other clasts in the metaconglomerate are generally more abundant, consisting of quartzite, amphibole schist, chlorite schist, sericite schist, biotite schist, and quartz–feldspar porphyry. They are likely host rocks of the pluton and, if so, are Late Proterozoic or older. The granite is interpreted as a terminal product of the Eocambrian rifting that preceded Paleozoic miogeoclinal sedimentation farther inboard. The continuity of pericratonic rocks west of the miogeocline and the occurrence of Proterozoic cratonic rocks at the surface west of the Okanagan Valley show that the ancient continental margin extends into a region where most of the crustal lithosphere was until now thought to consist of accreted Phanerozoic arc and accretionary complexes.L'assemblage de Spa Creek constitue une séquence distincte, mince et péri-cratonique qui recoupe la vallée de l'Okanagan dans l'arrière pays de l'orogène de la Cordillère sud, au Canada. La séquence a subi une déformation ductile et du métamorphisme avant d'être recouverte par les strates métaclastiques foncées du Trias. Un métaconglomérat à l'intérieur de la séquence, composé localement de plus de 90 % de fragments de granite à biotite, a donné cinq fractions de zircon automorphe qui définissent un paramètre cristallographique U–Pb supérieur précis de 555,6 ± 2,5 Ma, que l'on croit être l'âge d'un pluton avoisinant. D'autres fragments dans le métaconglomérat sont généralement plus abondants et comprennent du quartzite, du schiste à amphibole, du schiste à chlorite, du schiste à séricite, du schiste à biotite et des porphyres de quartz–feldspath. Ils sont probablement des roches encaissantes du pluton et, si c'est le cas, datent du Protérozoïque tardif ou sont plus anciens. Le granite serait un produit terminal d'une distension à l'Éocambrien qui a précédé la sédimentation miogéoclinale plus à l'intérieur. La continuité des roches péricratoniques à l'ouest du miogéocline et l'occurrence de roches cratoniques datant du Protérozoïque en surface, à ouest de la vallée de l'Okanagan, montrent que l'ancienne marge continentale s'étendait à l'intérieur d'une région où, jusqu'à présent, on croyait que la plus grande partie de la lithosphère crustale consistait de l'accrétion de complexes d'accrétion et de complexes d'arcs datant du Phanérozoïque.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

New palynological data from peaty sediments deposited during the Port Moody Interstade, at about 18 000 [sup 14] C years, indicate that the environment in the western Fraser Lowland of British Columbia consisted of subalpine forest and parkland with abundant fir and spruce that grew under a temperate and moist climate, similar to the wetter subzones of the present-day Engelmann Spruce – Subalpine Fir biogeoclimatic zone. The moist conditions interpreted for the Port Moody Interstade are consistent with recent computer modelling and earlier palynological data from unglaciated western Washington State, but appear to contradict regional Cooperative Holocene Mapping Project (COHMAP) reconstructions and some earlier palaeoenvironmental studies that support dry conditions. Strong seasonality is suggested as part of the explanation, with Pacific storms in summer following the southern margin of the last Cordilleran ice sheet, bringing abundant moisture to the study area during the growing season, but probably not in winter, when storm tracks were displaced to the south. The cold and dry anticyclonic winds postulated by COHMAP were probably also relatively weak in summer, resulting in stronger expression of moist Pacific air masses than previously thought. The timing of the Port Moody Interstade coincides with that of a short climatic fluctuation reported from several other sites in both the northern and southern hemispheres. These events, if causally related, suggest a rapidly propagated atmospheric–oceanic signal.De nouvelles données palynologiques provenant de sédiments tourbeux déposés durant l'interstade de Port Moody, il y a environ 18 000 [sup 14] C années, indiquent, pour l'ouest des basses terres de la rivière Fraser en Colombie-Britannique, un environnement de forêt subalpine et de prairie-parc avec beaucoup de sapins et d'épinettes qui ont crû dans un climat tempéré et humide, semblable aux sous-zones plus humides de la présente zone biogéoclimatique de l'épinette Engelmann – sapin subalpin. Les conditions humides trouvées pour l'interstade de Port Moody concordent avec les récents modèles informatiques et les données palynologiques antérieures de l'ouest de l'État de Washington qui n'a pas subi la glaciation, mais elles semblent contredire les reconstructions régionales COHMAP et quelques études paléoenvironnementales antérieures qui supportaient des conditions sèches. De forts cycles saisonniers pourraient fournir une explication partielle : en été, des tempêtes dans le Pacifique suivent la limite sud du dernier inslandis de la Cordillère, amenant ainsi beaucoup d'humidité à la région sous étude durant la saison de croissance, mais probablement pas en hiver, alors que les trajectoires des tempêtes sont déplacées vers le sud. Les vents anticycloniques frais et secs postulés par COHMAP étaient aussi probablement relativement faibles en été, donnant plus de force aux masses d'air humide du Pacifique que ce qui avait été postulé antérieurement. L'interstade Port Moody coïncide avec une courte fluctuation climatique enregistrée à plusieurs autres sites dans les hémisphères nord et sud. Si ces événements sont reliés par une cause commune, cela suggère un signal atmosphère/océan qui a été rapidement propagé.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

New U–Pb ages and K–Ar dates, primarily for rocks proximal to mineral occurrences in the Fawnie Range of central British Columbia, document latest Cretaceous (ca. 74–66 Ma) continental-arc igneous activity and date associated base and precious metal mineralization. U–Pb ages of ca. 73–69 Ma for the Capoose pluton and hypabyssal to extrusive garnet rhyolites at the Capoose prospect demonstrate a latest Cretaceous age for mineralization and a likely plutonic source for mineralizing fluids. A U–Pb age of ca. 67 Ma for a late mineralized felsic dyke and two K–Ar dates (ca. 70 and 68 Ma) for hornfelsed Jurassic volcanic rocks at the Blackwater–Davidson prospect constrain a latest Cretaceous age for mineralization. A U–Pb age of ca. 74 Ma for a fine grained diorite sill that cuts a significant epithermal gold vein at the Tsacha prospect places a minimum age on mineralization at this probable Jura-Cretaceous deposit and documents latest Cretaceous magmatism. Latest Cretaceous K–Ar dates are reported for an andesite flow adjacent to the Eocene Holy Cross deposit (ca. 66 Ma), about 35 km north of the Fawnie Range, and a Kasalka Group rhyolite (ca. 68 Ma) exposed near the western margin of the Nechako Plateau. Latest Cretaceous magmatism and mineralization in the Fawnie Range represent the waning stages of Bulkley suite magmatism and porphyry-style mineralization, which was concentrated along the western margin of the Nechako Plateau at circa 88–70 Ma. The distribution of latest Cretaceous arc igneous rocks along the North American Cordilleran is reviewed and tectonic implications discussed.De nouveaux âges U–Pb et de nouvelles datations K–Ar, surtout pour des roches à proximité d'occurrences minérales dans la chaîne Fawnie du centre de la Colombie-Britannique documentent la plus récente activité ignée d'arc continental au Crétacé (ca. 74–66 Ma) et datent la minéralisation associée de métaux précieux et de métaux de base. Des âges U–Pb d'environ 73–69 Ma pour le pluton de Capoose et les rhyolites grenatifères hypabyssales à extrusives dans la zone d'intérêt Capoose démontrent un âge Crétacé terminal pour la minéralisation et une source plutonique probable pour les fluides minéralisateurs. Un âge U–Pb d'environ 67 Ma pour un dyke felsique à minéralisation tardive et deux datations K–Ar (ca. 70 et 68 Ma) pour des roches volcaniques au faciès des cornéennes, datant du Jurassique, à la zone d'intérêt Blackwater–Davidson limitent l'âge de la minéralisation au Crétacé terminal. Un âge U–Pb d'environ 74 Ma pour un filon-couche de diorite à grains fins qui recoupe une importante veine d'or épithermale à la zone d'intérêt Tsacha donne un âge minimum pour la minéralisation de ce dépôt, probablement au Jurassique–Crétacé, et documente le magmatisme au Crétacé terminal. Des datations K–Ar de Crétacé terminal sont rapportées pour un écoulement d'andésite adjacent au gisement de Holy Cross, datant de l'Éocène (ca. 66 MA), situé à environ 35 km au nord de la chaîne Fawnie et pour une rhyolite du Groupe de Kasalka (ca. 68 Ma) affleurant près de la bordure ouest du plateau Nechako. Du magmatisme et de la minéralisation dans la chaîne Fawnie, au Crétacé terminal, représentent les dernières phases du magmatisme de la suite Bulkley et de la minéralisation de type porphyrique, qui a été concentrée le long de la bordure ouest du plateau Nechako il y a environ 88–70 Ma. On passe en revue la distribution des roches ignées d'arc au Crétacé terminal le long de la Cordillère nord-américaine et on discute des implications tectoniques.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

The Quaternary stratigraphy of the Nechako River – Cheslatta Lake area of central British Columbia is described and interpreted to reconstruct the late Quaternary history of the region. Exposures of glacial and nonglacial sediments deposited prior to the last glaciation (Fraser) are limited to three sites. Pollen assemblages from pre-Fraser nonglacial sediments at two of these sites reveal forested conditions around 39 000 BP. During the advance phase of the Fraser Glaciation, glacial lakes were ponded when trunk glaciers blocked some tributary valleys. Early in the glaciation, the drainage was free in easterly draining valleys. Subsequently, the easterly drainage was blocked either locally by sediments and ice or as a result of impoundment of the Fraser River and its tributaries east of the study area. Ice generally moved east and northeast from accumulation zones in the Coast Mountains. Ice flow was influenced by topography. Major late-glacial lakes developed in the Nechako River valley and the Knewstubb Lake region because potential drainage routes were blocked by ice.La stratigraphie du Quaternaire de la région de la rivière Nechako et du lac Cheslatta sise au centre de la Colombie Britannique est décrite et interprétée dans le but de reconstruire l'histoire du Quaternaire tardif de cette région. Seul trois coupes stratigraphiques mettent en évidence des sédiments glaciaires et non-glaciaires mis en place avant la dernière glaciation (Fraser). À deux sites, l'assemblage pollinique des sédiments non-glaciaires prédatant la Glaciation de Fraser reflète un environnement forestier aux environs de 39 000 BP. Lors de l'avancée des glaciers au début de la Glaciation de Fraser, des lacs glaciaires furent retenus dans les vallées secondaires par les glaciers qui occupaient les vallées primaires. Au début de cette glaciation, le drainage vers l'est fut tout d'abord ouvert mais subséquemment, il fut bloqué soit localement par des sédiments et de la glace ou en raison du blocage du fleuve Fraser et ses tributaires à l'est de la région d'étude. Les glaciers se sont écoulés vers l'est et le nord-est à partir de zones d'accumulation centrées sur la Chaîne Côtière. Les écoulements glaciaires furent influencés par la topographie. Des lacs post-glaciaires se sont formés dans la vallée de la rivière Nechako et dans la région du lac Knewstubb suite au blocage du drainage potentiel par la glace.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Provides information on the 4th International Workshop on Disturbance Dynamics in Boreal Forest held at the University of Northern British Columbia on August 9 to 12, 2002. Issues involving forest management discussed at the event; Keynote speakers who were present in the workshop; Discussion on the importance and role of disturbance in shaping boreal forest.

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Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper synthesizes data extracted from the literature and data collected in various studies by the author on the quantity, characteristics, and functional importance of coarse woody debris (CWD) in the old-growth forests of British Columbia (B.C.). There is little agreement in the literature about the minimum diameter of CWD or the number of decay classes recognized. In western North America, five decay classes are commonly used, but recent studies suggest fewer decay classes are preferable. Comparisons among decay classes and biogeoclimatic zones and subzones in B.C. reveal that quantities and volumes are greatest (up to approximately 60 kg/m[sup 2] and approximately 1800 m[sup 3] /ha, respectively), and CWD persists the longest (sometimes in excess of 1000 years) in the Coastal Western Hemlock (CWH) biogeoclimatic zone. The quantity and ground cover of CWD increase with forest productivity. Persistence of CWD has varied from less than 100 to over 800 years in two coastal (CWH and Mountain Hemlock (MH)) and three interior (Interior Douglas-fir (IDF), Interior Cedar–Hemlock (ICH), and Engelmann Spruce – Subalpine Fir (ESSF)) biogeoclimatic zones. Trends in CWD quantity with forest age in managed coastal B.C. forests suggest a U-shaped curve, with greater quantities occurring in recent cutovers than in old-growth forests, and lowest quantities occurring in middle-aged forests. This may be the normal trend in CWD with forest age, with departures from this trend resulting from disturbance- or environment-specific factors. Relatively large amounts of data exist on the characteristics of CWD in the CWH, IDF, ICH, ESSF, and Boreal White and Black Spruce (BWBS) biogeoclimatic zones, but such data for the Coastal Douglas-fir, Sub-Boreal Pine–Spruce, Sub-Boreal Spruce (SBS), and Spruce–Willow–Birch biogeoclimatic zones appear relatively sparse. There have been few studies of the functional role of CWD in B.C. forests, but those studies that have been completed indicate that CWD is an important habitat component for some plant and animal species. A total of 169 plant species, including >95% of all lichens and liverworts, were found to grow on CWD in old-growth forests in the CWH, MH, IDF, ICH, and ESSF biogeoclimatic zones. One third of these species were restricted to CWD. Studies in several biogeoclimatic zones have found that CWD provided preferred habitat for and was associated with higher populations of some small animal species, such as shrews, some voles, and some salamanders, in old-growth forests, but the effects varied with species and biogeoclimatic zone. The nutrient cycling role of CWD is not yet well known, but it currently appears to be relatively insignificant in B.C. old-growth forests. Although it has been considered that CWD could increase mineral soil acidification and eluviation, no evidence for this was found in a study of the CWH, MH, IDF, ICH, ESSF, BWBS, and SBS biogeoclimatic zones. Future studies of the functional role of CWD should consider both scale (square metre vs. hectare) and temporal (changes in CWD with forest age) issues, as studies including these are sparse and both may be important. Key words: biogeoclimatic zones, British Columbia, coarse woody debris, old-growth forests.Cette communication résume les données tirées de la littérature et celles recueillies par l'auteur dans diverses études sur la quantité, les caractéristiques et l'importance fonctionnelle des débris ligneux grossiers (DLG) dans les forêts anciennes de la Colombie-Britannique (C.-B.). Dans la littérature, on ne s'entend pas sur le diamètre minimum des DLG, ou le nombre de classes de décomposition. Dans l'ouest de l'Amérique du Nord, on emploie le plus souvent cinq classes, mais des études récentes portent à croire qu'un nombre de classes inférieur serait préférable. Les comparaisons entre les classes de décomposition et les zones et sous-zones biogéoclimatiques de la C.-B. révèlent que les DLG sont plus abondants (pouvant atteindre environ 60 kg/m[sup 2] et 1800 m[sup 3] /ha) et persistent le plus longtemps (parfois pendant plus de 1000 ans) dans la zone biogéoclimatique cótière de la pruche de l'Ouest (CWH). L'abondance des DLG et la superficie de sol qu'ils couvrent augmentent avec la productivité de la forêt. La persistance des DLG varie de moins de 100 ans à plus de 800 ans dans cinq zones biogéoclimatiques : deux zones côtières (la CWH et la zone de la pruche subalpine (MH)) et trois zones intérieures (celle du douglas taxifolié de l'intérieur (IDF), celle des cèdres et des pruches de l'intérieur (ICH) et celle de l'épinette d'Engelmann et du sapin subalpin (ESSF)). Dans les forêts côtières aménagées de la C.-B., l'abondance des DLG en fonction de l'âge de la forêt suivrait une courbe en U, les débris étant plus abondants sur les parterres de coupe récents que dans les forêts anciennes, et moins abondants dans les forêts d'âge moyen. Cette relation entre les DLG et l'âge de la forêt est peut-être la tendance normale, et les écarts par rapport à celle-ci pourraient être le résultat de facteurs propres à chaque perturbation ou milieu. Il existe beaucoup de données sur les caractéristiques des DLG dans la CWH, la IDF, la ICH, la ESSF et la zone boréale des épinettes blanche et noire (BWBS), mais il en existe relativement peu pour la zone côtière du douglas taxifolié, la zone subboréale des pins et des épinettes, la zone subboréale de l'épinette (SBS) et la zone de l'épinette, du saule et du bouleau. Peu d'études ont été consacrées au rôle fonctionnel des DLG dans les forêts de la Colombie-Britannique, mais d'après celles qui ont été réalisées, les DLG constitueraient une composante importante de l'habitat de certaines espèces végétales et animales. On a recensé 169 espèces végétales poussant sur ces débris, dont plus de 95 % de tous les lichens et hépatiques, dans les forêts anciennes de la CWH, de la MH, de la IDF, de la ICH et de la ESSF. Le tiers de ces espèces ne poussent que sur les DLG. D'après des études effectuées dans plusieurs zones biogéoclimatiques, ces débris constituent l'habitat préféré de certains petits animaux présents dans les forêts anciennes, tels que les musaraignes, certains campagnols et certaines salamandres, et sont associés à de plus fortes populations de ces animaux, mais les effets varient selon l'espèce et la zone biogéoclimatique. Le rôle des DLG dans le recyclage des éléments nutritifs n'est pas bien connu, mais il semble qu'il soit relativement négligeable dans les forêts anciennes de la C.-B. Il a été avancé que les débris ligneux grossiers pourraient accroître l'acidification et le lessivage des sols minéraux, mais de tels effets n'ont pas été mis en évidence dans une étude de la zone CWH, de la MH, de la IDF, de la ICH, de la ESSF, de la BWBS et de la SBS. À l'avenir, les études sur le rôle fonctionnel des DLG devraient tenir compte des aspects liés à l'échelle (m[sup 2] ou ha) et temporels (modifications des DLG avec le vieillissement de la forêt) puisque les études impliquent ces paramètres potentiellement importants sont rares. Mots clés : zones biogéoclimatiques, Colombie-Britannique, débris ligneux grossiers, forêts anciennes. [Traduit par la rédaction] [ABSTRACT FROM AUTHOR]

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Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Presents a correction to the study 'An 1800-Year Record of the Spatial and Temporal Distribution of Fire From the West Coast of Vancouver Island, Canada,' by Daniel G. Gavin, Linda Brubaker and Kenneth P. Lertzman.

Laboratory experiments were conducted with the millipede Harpaphe haydeniana haydeniana Wood (Polydesmida: Xystodesmidae) to determine (i) its litter feeding preferences, (ii) rates of leaf litter consumption, (iii) feeding effects on available nitrogen, and (iv) functional microbial diversity. The millipede exhibited a preference for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and, to a lesser extent, Sitka spruce (Picea sitchensis (Bong.) Carriere) litter compared withwestern hemlock (Tsuga heterophylla (Raf.) Sarg.) and western redcedar (Thuja plicata Donn ex D. Don) litter when given a choice. When only one litter type was provided, millipedes consumed considerably more western redcedar than Douglas-fir, Sitka spruce, or western hemlock. Among the six broadleaf species tested, paper birch (Betula papyrifera Marsh.), bigleaf maple (Acer macrophyllum Pursh), vine maple (Acer circinatum Pursh), and red alder (Alnus rubra Bong.) were consumed at much higher rates than swordfern (Polystichum munitum (Kaulf.) Presl.) or salal (Gaultheria shallon Pursh). Daily rates of conifer litter consumption ranged between 10 and 20% of the millipede's fresh biomass and may translate to 36% of the annual litter fall. Our results suggest that transformation of conifer litter into millipede frass can increase rates of litter decomposition and N mineralization, as well as influence microbial activity and diversity in coastal forests. [ABSTRACT FROM AUTHOR]

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Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Fisheries & Aquatic Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)