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Red heartwood, a dark nonhomogenous discolouration in paper birch trees ( Marsh.), limits the applications and uses of sawn boards to nonvisible low-value products, thus resulting in substantial value loss. The occurrence and distribution of red heartwood were investigated in 12 paper birch trees grown in the province of Quebec, Canada. The youngest tree was 62 years old at breast height and the oldest 86 years old for an average of 75 years old. In this study, 225 occurrences of external traits, relating to branch scars and forks, previously proposed as initiation points for red heartwood were identified and measured. The distribution of red heartwood was digitally mapped and the effect of these external traits on the red heartwood surface and shape inside each tree was examined. Results show that red heartwood initiates from an external trait and that multiple external traits can contribute to the development of a red heartwood column following the longitudinal axis of the stem. Red heartwood appeared to initiate mainly from external traits at the base of the tree. A modelling exercise indicated that the width of the red heartwood column inside a standing tree can be estimated from branch scar width and height from the ground. Tree vigour could not be linked to the proportion of red heartwood inside standing trees. A three-dimensional analysis of log shape could potentially be used to detect red heartwood presence in a log before processing to optimize the log sawing pattern. [ABSTRACT FROM AUTHOR]

Normal paper birch (Betula papyrifera Marsh.) wood has a clear and uniform color. However, some paper birch trees contain reddish-brown-, discolored wood known as red heartwood. Its occurrence, proportion, and vertical distribution were investigated. One hundred and fifty trees were randomly sampled from three stands located at the Montmorency Forest, 75 km north of Quebec City, Quebec, Canada. A subsample of 18 trees showing occurrence of red heartwood at stump height were felled, and 5 cm thick disks were cut at every 0.5 m of height. Red heartwood volume, proportion, and vertical distribution were determined from the disks. Trees with larger diameter at breast height and lower tree height had a higher probability of red heartwood occurrence. Red heartwood starts occurring in 40-year-old trees on average in the stands studied. The volume of red heartwood was positively correlated with tree age, and the proportion of red heartwood was positively related to tree age, and negatively related to the amount of sunlight on the live crown. Red heartwood proportion was 13.3% of the tree merchantable volume, mostly located under the live crown. Le bois de bouleau à papier (Betula papyrifera Marsh.) est normalement clair et uniforme. Toutefois, le bois de couleur brun-rougeâtre présent chez certains bouleaux est appelé cœur rouge. Sa présence, sa proportion et sa distribution verticale dans l’arbre ont été étudiées. Cent cinquante arbres furent sélectionnés aléatoirement dans trois peuplements de la Forêt Montmorency à 75 km au nord de la ville de Québec, Québec, Canada. Un sous-échantillon de 18 arbres présentant du cœur rouge à hauteur de souche ont été abattus et découpés en disques de 5 cm d’épaisseur à tous les 5 m afin de mesurer le volume, la proportion et la distribution verticale du cœur rouge. La probabilité de présence de cœur rouge était plus élevée chez les arbres petits et de fort diamètre. Le cœur rouge était présent dans les arbres de 40 ans et plus en moyenne dans les peuplements étudiés. Le volume de cœur rouge était corrélé positivement avec l’âge de l’arbre. Sa proportion était corrélée positivement avec l’âge de l’arbre et négativement avec la quantité de lumière atteignant la cime vivante. La proportion moyenne de cœur rouge était 13,3 % du volume marchand de l’arbre et il était principalement situé sous la cime vivante. [ABSTRACT FROM AUTHOR]

Ecosystem management requires good knowledge of preindustrial ecosystems and their dynamics. However, in most regions of Québec, the original forested landscape has been altered by human activities. To validate the ecosystem management conducted in the lower Mauricie region, the preindustrial landscape of the high hills of the lower Saint-Maurice region was characterized from the study of 18 historical forest surveys conducted by the pulp and paper industry in the early 20th century. The analysis of these surveys showed the predominance of irregular mature stands. Two-thirds of these stands were of mixedwood type, while a very small proportion was of hardwood type. Softwood volume was mainly constituted of balsam fir (Abies balsamea (L.) Mill.) and red (Picea rubens Sarg.) and black spruces (Picea mariana (Mill.) BSP). Lastly, the analysis of these inventories showed the occurrence, in the preindustrial landscape, of a mixed disturbance regime, where severe fires and insect outbreaks coexisted with gap dynamics. From a broader perspective, we can fully appreciate with this study the importance and usefulness for ecosystem management of conserving forest inventory archives, because in many cases they are the only references to the preindustrial landscape. [ABSTRACT FROM AUTHOR]

The article offers information about several research papers related to various aspects of food and nutrition. It includes food security of Syrian refugee households in Canada, maternal mental health and infant feeding style, childcare director perceptions on healthy food consumption, the effect of food advertisements on food intake, and associations between intuitive eating levels and desire to eat during pregnancy.

This paper presents an experimental program to justify the barrier design at the barrier-deck junction when compared to the factored applied transverse vehicular loading specified in the Canadian Highway Bridge Design Code (CHBDC). Compared to the dimensioning and the glass fibre reinforced polymer (GFRP) bar detailing of a recently crash-tested GFRP-reinforced barrier, the adopted barrier configurations in this paper were similar to those specified by Ministry of Transportation of Québec (MTQ) for TL-5 barrier except that the base of the barrier was 40 mm narrower and the deck slab is of 200 mm thickness, leading to reduction in the GFRP embedment depth into the deck slab. Four full-scale TL-5 barrier specimens were tested to collapse. Correlation between the experimental findings and the factored applied moments from CHBDC equivalent vehicle impact forces resulting from the finite-element modelling of the barrier-deck system was conducted followed by recommendations for use of the proposed design in highway bridges in Québec. [ABSTRACT FROM AUTHOR]

Quebec's forests represent 20% of Canadian forests and 2% of the world forests. Over the entire planet, forests play a major role in habitat preservation and in supplying goods and services to the population. However, climate change will have an impact on the forest through inter alia increased droughts, forest fires, warmer weather, and infestations. In this paper, we analyze the economic impact of climate change on the forest industry in Quebec over a 40-year period using a recursive dynamic computable general equilibrium model. We find that the climate change effects will be relatively weak on most macroeconomic variables as agents adjust their behavior over time and factors are reallocated across sectors. We find that climate change could generate losses in gross domestic product of up to Can$300 million (0.12% of gross domestic product) at the end of a 40-year period for Quebec's economy. However, we find relatively more important effects within the sectors of the forest industry, with losses ranging from 3% to 7.5%. [ABSTRACT FROM AUTHOR]

This paper presents development of a multivariate forest structural complexity index based on relationships between field-based structural variables and geospatial data. Remote sensing has been widely used to model individual forest structural attributes at many scales. As opposed to, or in addition to, individual structural parameters such as leaf area index or tree height, overall structural complexity information can enhance forest inventories and provide a variety of information to forest managers, including identifying damage and disturbance as well as indicators of habitat or biodiversity. In this study, a multivariate modelling technique, redundancy analysis, was implemented to derive a model incorporating both horizontal and vertical structural attributes as predicted by an ensemble of high-resolution multispectral airborne imagery and topographic variables. The first redundancy analysis axis of the final model explained 35% of the total variance of the field variables and was used as the complexity index. With a root mean squared error of 19.9%, the model was capable of differentiating four to five relative levels of complexity. This paper presents the forest ecological and modelling aspects of the research. A related paper presents the remote sensing aspects, including application of the model to map predicted structural complexity, map validation, and testing of the method at multiple scales. Cet article présente le développement d'un indice multivarié de complexité de la structure de la forêt basé sur les relations entre des variables structurales mesurées sur le terrain et des données géospatiales. La télédétection a été largement utilisée pour modéliser les attributs structuraux de la forêt à plusieurs échelles. Contrairement à, ou en plus, des paramètres structuraux individuels comme l'indice de surface foliaire ou la hauteur des arbres, une information globale au sujet de la complexité structurale peut améliorer les inventaires forestiers et fournir une variété de renseignements aux aménagistes forestiers, incluant l'identification des dommages et des perturbations aussi bien que des indicateurs d'habitat ou de biodiversité. Dans cette étude, une technique de modélisation multivariée, l'analyse de redondance, a été appliquée pour dériver un modèle qui incorpore des attributs, tant horizontaux que verticaux de la structure, prédits par un ensemble d'images aériennes multispectrales à haute résolution et des variables topographiques. Le premier axe de l'analyse de redondance du modèle final expliquait 35 % de la variance totale des variables terrain et a été utilisé comme indice de complexité. Avec une erreur quadratique moyenne de 19,9 %, le modèle était capable de différencier quatre à cinq niveaux de complexité. Cet article présente les aspects de la recherche reliés à la modélisation et à l'écologie forestière. Un autre article présente les aspects reliés à la télédétection, incluant l'application du modèle pour cartographier la complexité structurale prédite, la validation de la cartographie et l'essai de la méthode à plusieurs échelles. [ABSTRACT FROM AUTHOR]

To assess nutrient dynamics in decomposing logs of trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.), white spruce (Picea glauca (Moench) Voss), and jack pine (Pinus banksiana Lamb.), we monitored mass losses and changes in N and P contents in dead boles from a chronosequence of sites following stand-replacing disturbances. To assess the importance of wood decomposition to nutrient cycling, we compared net estimates of nutrient release from logs with net nutrient immobilization in live-tree biomass of stands as a function of time since disturbance. Mineralization rates were 0.060, 0.053, 0.038, and 0.020·year–1 for trembling aspen, white birch, white spruce, and jack pine logs, respectively. Trembling aspen boles released large quantities of N and P during the first year of decomposition (51 kg·ha–1 of N and 7 kg·ha–1 of P, assuming a bole volume of 150 m3·ha–1). White birch boles acted initially as a nutrient sink and delayed the release of immobilized nutrients until a period when the stand's net nutrient immobilization rates were highest. Jack pine boles appeared to be intermediate in terms of their contribution as a sink or a source of nutrients but, in mature stands, provided up to 40% of N and 26% of P immobilized annually in tree biomass. As pure stands of white spruce are rare in boreal Quebec, information on nutrient accumulation in white spruce stands was not available. [ABSTRACT FROM AUTHOR]

There is evidence that extreme ice loads combined with moderately high winds may cause catastrophic damage to overhead power lines and prolonged periods of electrical power outage. In this paper, a probabilistic model for combined wind and ice loads was developed for establishing realistic and conservative criteria for design and normalization. The proposed model combines icing of extreme thickness with a moderate wind speed, Vice, reduced by a reduction factor, kr, with respect to the extreme wind speed, Vmax. The evaluation of kr, which is the main purpose of this paper, is done by means of statistical analysis of samples taken from the same initial distribution of hourly wind speeds, Vh. The size of samples corresponds to the average annual icing persistency period, Tipp, observed in the climatic conditions of Quebec. This period, which was established in an earlier study by the authors using statistical analysis of data from the Hydro-Québec passive ice meter (PIM) network, is evaluated to be on average 144 h/year. It was found that kr ranges from 0.4 to 0.7, mainly as a function of the coefficient of variation (COV) of the initial distribution of wind speeds and the return period prescribed for extreme climatic loads. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to describe the characteristics of brash ice in the St. Lawrence River downstream of Montréal over a period of three winters. We used two instruments deployed in the St. Lawrence River navigation channel through Lake St. Pierre to measure ice parameters: an acoustic Doppler current profiler (ADCP) and an ice-profiling sonar (IPS). This paper discusses the capacities of these instruments to quantify ice characteristics and to predict the risk of ice congestion. It was found that wind velocity and air temperature play major roles in the variation in ice parameters and, consequently, in the occurrence of ice congestion in the navigation channel through Lake St. Pierre. Comparison of the IPS and ADCP data showed good agreement and demonstrated that these two instruments can be very effective for certain ice applications. [ABSTRACT FROM AUTHOR]

The Kamouraska Formation is a quartz-arenitic unit of latest Cambrian - earliest Ordovician age in the Quebec Appalachians that was deposited by hyperconcentrated to concentrated density flows in a meandering submarine canyon on the continental slope bordering the Iapetus Ocean, as outlined in a companion paper. Detailed petrographic study of the quartz arenites of the Kamouraska Formation combined with scanning electron microscopy of grain surface textures suggests that the quartz sands are of eolian origin having been derived from an inland desert or, less likely, a barrier beach dune system. Transport of the mature quartz-arenitic sand onto the shelf and deposition into the deep sea was not accompanied by substantial mixing with material from other sources thus preserving the inherited eolian characteristics. A modern analogue for the eolian interpretation of the deep-sea quartz-arenite beds is as follows: thick, Late Pleistocene eolian sand beds on a modern abyssal plain in the East Atlantic referred to as eolian-sand turbidites that were deposited in the deep sea during glacial sea level lowstands when eolian sand transport to canyon heads was enabled by an exposed and shortened shelf. Similarly, an established sea level lowstand at the Cambro-Ordovician boundary would have facilitated the introduction of eolian sand of the Kamouraska Foundation into canyon heads on the upper slope from where turbidity currents and related density flows were triggered. Correlation of the Kamouraska Formation with the quartz arenites of the Cairnside Formation of Quebec (Keeseville Formation in northern New York State, Nepean Formation in southern Ontario) links the deep-sea deposits with remnants of an inland dune system. [ABSTRACT FROM AUTHOR]

The poor seismic performance of schools has made their assessment and retrofit a priority in moderate and high seismic zones. Given the large building inventory to evaluate, rapid seismic screening methods are often implemented to prioritize detailed interventions. This paper describes schools' specific characteristics to be considered when applying these procedures, and shows how the FEMA154 approach can be modified to consider them. The adapted method is a score assignment procedure based on the following six essential characteristics: seismicity, lateral load resisting system, construction year, potential structural weaknesses (or irregularities), potential for pounding of adjacent buildings, and local soil conditions. The method is illustrated with case studies, applied to 101 school buildings in Quebec. Results show that most of the parameters considered influence the final scores. In particular, the treatment of structural weaknesses and potential for pounding proved effective in differentiating the likely seismic performance of the buildings. [ABSTRACT FROM AUTHOR]

In many northern forest ecosystems, the postfire transition from a closed-crown forest to open woodland is often observed but poorly understood. This paper looks at the effect of interactions between surficial deposit, climate, and fire cycle on postfire forest recovery within a large territory (190 000 km2) of the boreal forest of eastern Canada. Postfire recovery was estimated using the time elapsed to move from the burnt stage to the regenerated stage and the young forest stage. The main objective was to determine if forests situated in dry regions (characterized by a high proportion of dry coarse surficial deposits, low precipitation, and short fire cycle) tend to reestablish more slowly after fire, obtaining a more open stand compared with wetter regions characterized by a longer fire cycle. To identify the best explanatory model for postfire recovery, multinomial logistic regressions with the Akaike information criterion were conducted using a combination of physicoclimatic factors. Our best model suggests that the most significant predictors of postfire recovery are time since fire (χ2 = 1370.06), surficial deposit type (χ2 = 651.95), the Canadian Drought Code (χ2 = 247.75), and the growing season precipitation (χ2 = 102.80). Fast recovery and dense forest regeneration are associated with subhydric till deposits only in the regions characterized by a long fire cycle (>500 years). Conversely, slow regeneration conducive to a sparse young forest was usually associated with regions characterized by a short fire cycle (<200 years) underlain by dry coarse deposits such as juxtaglacial but also mesic deposits in some cases. Our results also show that slow recovery and reduced forest regeneration are most likely to occur following fires that occurred in dry years, regardless of the deposit type and region. [ABSTRACT FROM AUTHOR]

Sewer deterioration, prevalent in municipalities throughout Canada, prompted the Quebec provincial government to implement a 1% renewal rate of the conduit facilities as to meet the goals of the national water plan adopted in 2002. Some of the most affected municipalities are usually the ones already under tight budget constraints, and cannot therefore afford the use of CCTV inspections in assessing the state of their sewage systems. This paper proposes a probabilistic model devised to survey the current conduit deterioration state caused by maintenance and operational conditions. Based on the multinomial logistic regression, this model - successfully applied to a case study in Quebec - shows the temporal deterioration of conduits for different material types. On average, it correctly predicted 54% of outcomes for transition probabilities involving both condition classes 1 (excellent) and 2 (good), and it showed a 59% correct prediction for class 3 condition (fair). This model is a recommended tool - applicable in combination with current exploratory techniques - for an effective prevention of conduits failure. [ABSTRACT FROM AUTHOR]

This paper examines the problem of finding an optimal operating policy for Hydro-Quebec's Manicouagan River and Outardes River hydroelectric installations. The solution method is based on the sampling dynamic programming (SSDP) algorithm. We use a new hydrologic state variable to capture the inflows regime, and this variable is given by a linear combination of the snow water equivalent and soil moisture. In real-time operation, this variable is calculated by a hydrologic model and incorporated in the operating policy to calculate the water released at each power plant. The algorithm is compared to the lag-1 stochastic dynamic programming (SDP) already implemented at Hydro-Québec, through a statistical analysis with a set of 40 synthetic historical inflow scenarios obtained by hydrologic modeling, using synthetic temperature and precipitation produced by a stochastic weather generator. The results of the analysis show that the SSDP operating policy is statistically superior to the operating policy of the lag-1 SDP model. The SSDP operating policy does not underestimate the volume of runoff occurring during the spring season contrary to SDP. Consequently, there is a reduction in the hm3 of water spilled, while the average annual generation is increased. [ABSTRACT FROM AUTHOR]

The Archean Blake River Group (BRG) of Ontario and Quebec is dominated by submarine mafic to intermediate lavas, with more restricted felsic volcanic rocks. Given the good quality of outcrop, and high level of preservation of some BRG rocks, the mafic to intermediate lavas were used in the 1970s and 1980s to better understand the evolution of massive and pillowed submarine flows, and their associated fragmental facies (pillow breccias, hyaloclastite). Potentially, the BRG could also represent a useful volcanic succession for the study of explosive submarine eruption products in the ancient record. Before this is possible, however, a regional inventory of the mafic to intermediate volcaniclastic units is needed to clarify their characteristics and origins. In this paper, we compare and contrast volcaniclastic rocks from three areas within the same formation of the northern BRG in Quebec: the Monsabrais area, the Lac Duparquet area, and the D'Alembert tuff area. Close examination reveals pronounced differences in terms of lateral continuity, thickness, grading, bedding, clast shapes, textures, etc. in the volcaniclastic rocks. These differences are interpreted to reflect vastly different emplacement processes, ranging from hyaloclastite generation as a result of self-fragmentation and lava contact with water (dominant in the Monsabrais and Lac Duparquet areas) to aqueous density currents likely fed directly by explosive submarine eruptions (dominant in the D'Alembert tuff). [ABSTRACT FROM AUTHOR]

In the Archean Blake River Group, mafic to intermediate fragmental units have controversially been proposed to have formed during the collapse of a giant submarine caldera. This paper describes and interprets these rocks, summarizing their physical characteristics, inferred origins, age relationships, and geochemical signatures. The widespread Stadacona member, south of Rouyn-Noranda, consists of several hundred metres of bedded volcaniclastic rocks interpreted to have been mostly deposited from aqueous density currents fed directly by explosive eruptions. The magmas involved in these eruptions were plagioclase-phyric, tholeiitic to transitional basalts. The similarly widespread D'Alembert tuff, in the northern part of the Blake River Group, shares many physical characteristics with the Stadacona member and is thought to have a similar origin. However, the D'Alembert tuff is approximately six million years younger than the Stadacona member. It is composed mostly of transitional to calc-alkaline andesites and basaltic andesites with very distinct trace element profiles. Volcaniclastic rocks from other areas, such as Tannahill Township in Ontario and the Monsabrais area in Quebec, are interpreted to represent mostly in situ to remobilized hyaloclastite, with no explosive eruptions involved in their genesis. Our observations and interpretations are not compatible with models in which the volcaniclastic units are emplaced during a catastrophic event in relation with the collapse of a giant caldera. Instead, the fragmental rocks were produced by various mechanisms at many distinct times during the evolution of the Blake River Group. [ABSTRACT FROM AUTHOR]

This paper presents the results of an exploratory analysis of falling weight deflectometer (FWD) data collected on a large project about the spring thaw behaviour of pavements. The test site includes four test sections, two of which are conventional flexible pavement structures, whereas the other two are built with a cement-treated base. The aim of this study is to verify the applicability of using FWD time history data to evaluate damage to a road during the thawing period. The applicability of the analysis techniques is verified through the phase angle and dissipated energy. The data analyzed were obtained from tests conducted with an FWD on one flexible pavement test section. The results obtained showed a clear difference between the winter, thawing, and summer periods. It was found that the phase angle and dissipated energy can be used to evaluate the road damage during the thawing period through quantification of the phase angle and dissipated energy. These factors can also be used to describe the pavement behaviour in terms of elasticity and viscoelasticity. Cet article présente les résultats d'une analyse exploratoire de données de déflectomètre à masse tombante (FWD) colligées lors d'un grand projet sur le comportement des chaussées lors du dégel du printemps. Le site d'essai comprend quatre sections : deux ont des structures conventionnelles de chaussée flexible et les deux autres sont construites sur une fondation traitée au ciment. L'objectif de l'étude est de vérifier l'applicabilité des données historiques FWD pour évaluer le dommage à la route durant la période de dégel. L'applicabilité des techniques d'analyse est vérifiée par l'angle de phase et l'énergie dissipée. Les données analysées ont été obtenues lors d'essais réalisés avec le déflectomètre à masse tombante sur une section d'essai de chaussé flexible. Les résultats montrent une différence évidente entre les périodes d'hiver, de dégel et d'été. Il s'est avéré que l'angle de phase et l'énergie dissipée peuvent être utilisés pour évaluer les dommages à la route durant la période de dégel en quantifiant l'angle de phase et l'énergie dissipée et en décrivant le comportement de la chaussée en termes d'élasticité et de viscoélasticité. [ABSTRACT FROM AUTHOR]

This paper describes a study of the seismic behaviour of taller eccentrically braced frames (EBFs). Chevron-type EBFs with shear-critical links are designed for 14-, 20-, and 25-storey buildings in Montreal and Vancouver. For each location the importance of different design criteria is discussed and an appropriate design sequence is proposed. It was found that ductility requirements did not control design. For Vancouver, buildings member selection was mostly influenced by the inelastic inter-storey drift requirements whereas for Montreal ensuring the global frame stability was critical. The seismic response of these frames to the sets of earthquake records calibrated to match design spectra is described. The seismic performance for Vancouver frames was found to be adequate, except that in the upper storeys the inelastic link deformations and shear forces exceeded values anticipated in design. For the Montreal structures, all global and local response indicators remained well below the design limits. [ABSTRACT FROM AUTHOR]

The boreal forest of higher latitudes constitutes a reservoir of trees of great ecological importance and unknown economic potential, but the stand dynamics in these regions still remain essentially unexplored. This paper examines the change in age and size structures during stand development on the northern border of the natural closed boreal forest in Quebec, Canada. Height, diameter, and age of trees were measured in 18 plots with stand ages between 77 and 340 years. The occurrence, size, and origin (layer or seed) of seedlings and saplings were assessed in subplots. Tree density ranged from 600 to 3750 trees·ha–1. Picea mariana (Mill.) BSP was the dominant species, mainly originating by layering. A cluster analysis segregated plots into even-aged and uneven-aged stands according to tree age, but size distribution of trees, saplings, and seedlings did not differ statistically between the two groups. Even-aged stands exhibited a 60% probability of assuming an uneven-aged structure between 120 and 200 years after stand initiation. At high latitudes, the closed boreal forest of P. mariana appears homogeneously sized, with similar distributions of diameter and height across all stages of stand development. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to evaluate whether future climate change would trigger an increase in the fire activity of the Waswanipi area, central Quebec. First, we used regression analyses to model the historical (1973–2002) link between weather conditions and fire activity. Then, we calculated Fire Weather Index system components using 1961–2100 daily weather variables from the Canadian Regional Climate Model for the A2 climate change scenario. We tested linear trends in 1961–2100 fire activity and calculated rates of change in fire activity between 1975–2005, 2030–2060, and 2070–2100. Our results suggest that the August fire risk would double (+110%) for 2100, while the May fire risk would slightly decrease (–20%), moving the fire season peak later in the season. Future climate change would trigger weather conditions more favourable to forest fires and a slight increase in regional fire activity (+7%). While considering this long-term increase, interannual variations of fire activity remain a major challenge for the development of sustainable forest management. [ABSTRACT FROM AUTHOR]

Modelling volumes by log grades in standing hardwood trees is often hindered by the nature of the response variable. In this paper, we used a two-part conditional model to account for the excess of zero responses for some log grades. Moreover, this approach was used as a framework to compare three different tree classifications in their ability to predict volumes by log grades in standing yellow birch (Betula alleghaniensis Britton) and sugar maple (Acer saccharum Marsh.) trees. A tree grade classification was compared with two preharvest tree classifications based on mortality risk assessment. A cross-validation was also carried out to evaluate the two parts of the model. The results showed that the two-part conditional approach was efficient in this case study. Compared with a general model, the three classifications improved the maximum likelihood. According to the Akaike and Bayesian information criteria, the tree grade classification was the “best” one. All three classifications proved to be better able to distinguish log grade occurrence than log grade volume. Although it implies additional cost, the implementation of the tree grade classification into the preharvest inventories would improve the prediction of volumes by log grades for yellow birch and sugar maple trees. [ABSTRACT FROM AUTHOR]

This paper presents soil fluxes of methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) from 12 sites located in four major forest types, black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), aspen (Populus spp.), and alder (Alnus spp.) stands, in the Eastmain and Chibougamau regions of Quebec. Fluxes were determined with closed chambers during the snow-free period from May to October 2007. Well-drained black spruce, jack pine, and aspen forest soils were net sinks of atmospheric CH4 (–0.33 ± 0.11 mg·m–2·day–1), while alder-dominated wetland soils were sources of CH4 (0.45 ± 0.12 mg·m–2·day–1). The cut-over alder wetland soil produced 131 times more CH4 than the undisturbed wetland soil. Soil moisture and temperature mainly regulated CH4 fluxes. N2O fluxes from these forest soils were highly variable and smaller (1.6 ± 0.33 µg N·m–2·h–1) than those from deciduous forest soils. N2O emission from the cut-over black spruce forest soil was 2.7 times greater than that from the mature black spruce forest soil. Large C/N ratios (27 to 78) and slow soil N mineralization and nitrification rates in these forest soils may have led to small N2O fluxes. CO2 emissions from these forest soils, ranging from 0.20 to 2.7 g·m–2·day–1, were mainly controlled by soil temperature. [ABSTRACT FROM AUTHOR]

The objective of this paper is to compare field test results obtained in a stiff sensitive clay from Quebec using prebored, instrumented sharp cone tests (ISCTs) with those deduced from prebored and self-boring pressuremeter tests (PMTs and SBPMTs, respectively) and vane shear tests (VSTs). Comparisons are also made with triaxial test results. It is shown that undrained shear strengths Su deduced from PMTs and ISCTs are greatly overestimated with respect to the values inferred from SBPMTs and VSTs. As for the shear modulus G, the opposite is true. These discrepancies are considered to arise from initial disturbance and unloading caused by drilling of pilot holes in the case of PMTs and ISCTs. Interpretation problems may be also related to the existence of very high lateral pressures at rest in the clay deposit. L’objectif de cet article est de comparer les résultats d’essais in situ obtenus dans une argile sensible raide du Quebec à l’aide d’essais au cône effilé instrumenté préforé « ISCT »avec ceux déduits d’essais au pressiomètre autoforeur et préforé « SBPMT et PMT, respectivement , et d’essais scissométriques de chantier « VST ». Une comparaison est effectuée aussi avec les résultats obtenus au laboratoire au moyen d’essais triaxiaux. Il est montré que les valeurs de la résistance au cisaillement non drainé Su, déduites des essais pressiométriques et au cône effilé préforés, sont beaucoup plus élevées que celles obtenues au pressiomètre autoforeur et au scissomètre. Par contre, les modules de cisaillement G sont beaucoup plus faibles dans les essais pressiométriques et au cône effilé préforés. Ces différences sont probablement dues au remaniement et au déchargement initial du sol, causés par le forage des avant-trous utilisés pour effectuer les essais au pressiomètre et au cône effilé préforés. Les problèmes d’interprétation peuvent être aussi le résultat de l’existence de pressions latérales au repos très élevées dans le dépôt argileux. [ABSTRACT FROM AUTHOR]

This paper presents the construction details, field testing, and analytical results of six innovative concrete bridges reinforced with fibre-reinforced-polymer (FRP) bars recently constructed in North America, namely Wotton, Magog, Cookshire-Eaton, Val-Alain, and Melbourne bridges in Quebec, Canada, and Morristown bridge in Vermont, USA. All six bridges are girder type, with main girders made of either steel or prestressed concrete. The main girders are supported over spans ranging from 26.2 to 50.0 m. The deck is a 200–230 mm thick concrete slab continuous over spans of 2.30–3.15 m. Different types of glass- and carbon-FRP reinforcing bars and conventional steel were used as reinforcement for the concrete deck slab. The six bridges are located on different highway categories, which means different traffic volume and environmental conditions. The bridges are well instrumented at critical locations for internal temperature and strain data collection using fibre optic sensors. These sensors are used to monitor the deck behaviour from the time of construction to several years after the completion of construction. The bridges were tested for service performance using calibrated truckloads. In parallel, a finite element analysis (FEA) was conducted and verified against the results of the field load tests. The FEA was then used to run parametric studies to investigate the effect of several important parameters such as FRP reinforcement type and ratio on the service and ultimate behaviour of these bridge decks. The analytical and field results under real service conditions, in terms of deflections, cracking, and strains in reinforcement and concrete, were comparable to those of concrete bridge deck slabs reinforced with steel. [ABSTRACT FROM AUTHOR]

Post-earthquake inspection is required by many dam safety regulations. Typically, based on the magnitude of the earthquake, the guidelines define an area within which dams should be inspected. The areas are established on ground-motion relations derived for the western United States. In eastern North America (ENA), the attenuation is slower with distance from the earthquake epicentre, and as a consequence the inspection area should be significantly larger than that recommended by the current guidelines. We review the state of knowledge on earthquake damage to dams, the factors used to define post-earthquake inspections, and the earthquake characteristics used to define the guidelines. We recommend new radii of inspections for dams applicable in ENA, including the Province of Quebec. Derived from historical earthquake information, the proposed new radii of inspections are twofold to sixfold larger than the 1988 guidelines of the International Commission on Large Dams. It is also suggested that a half-magnitude unit be added to every magnitude “rapidly” released by seismological organizations to include the intrinsic uncertainty in magnitude values and types. Our proposed approach is only one avenue that dam owners can follow to comply with dam safety regulations. Irrespective of the avenue chosen, however, this paper emphasizes the need for dam owners to consider the lower ground motion attenuation in ENA. [ABSTRACT FROM AUTHOR]

This paper examines structural changes and the dynamics of price relationships in the United States (US), British Columbia, Quebec, and Ontario lumber markets. With monthly price series from 1981 to 2002, I used Perron's method to identify structural shifts and the Johansen cointegration analysis and vector-error correction model to determine both short- and long-run price relationships. I found that because of restrictions on federal timber harvests in the Pacific Northwest, price instability experienced in 1992 has caused structural shifts for the US and Canadian lumber prices. I also found that the North American lumber market is indeed integrated, with the US price significantly affecting Canadian prices in both the short and long run. This further indicates that the US market plays a dominant role in price setting in the North American lumber market, as Canadian prices respond to the US price change, but the reverse situation does not occur. [ABSTRACT FROM AUTHOR]

Located some 90 km north of the town of Sept-Îles, Quebec, the Sainte-Marguerite-3 (SM-3) hydroelectric project was one of the most ambitious in eastern North America in recent years. The project included the construction of a 171 m high dam that created a 140 km long reservoir, some 120 m deep near the dam toe. Although the reservoir is located in a weakly seismic area of the Canadian Shield, reservoir-induced earthquakes occurred. A first event (mN 1.3) was recorded in September 1999, ~17 months after the reservoir started filling. Between October 2000 and March 2001, four additional events were detected by the Canadian National Seismograph Network, the largest being mN 1.7. During a field survey that took place between July and October 2001, 276 events of magnitude mN ≤ 1.2 were detected within 30 km of a three-component seismograph. Single-station locations, confirmed by agreement between P phase and S phase azimuths, were determined for 182 events. Most earthquakes fall in four areas with estimated focal depths mostly shallower than 2 km. Since the field survey completion, more events have taken place, but the largest one is mN 2.2 as of March 2006. This paper presents a detailed analysis of the reservoir-triggered events, together with a summary of seismic hazard evaluation of the dam site, the seismic parameters selected for dynamic analysis, and the selection of the design earthquake. [ABSTRACT FROM AUTHOR]

Safe dam design, especially when the dam is likely to erode when submerged, must take into account wave surge. The lack of data for small structures built in a forest environment is a problem when assessing this surge. This paper proposes an approach to assess wave surge for these structures. The proposed approach is based on relationships developed by Saville et al. (1962) for inland lakes. An example to illustrate the application of this approach is discussed in the framework of the Quebec Dam Safety Regulation (Quebec Government 2002). [ABSTRACT FROM AUTHOR]

We studied community development and mortality among tree species at multiple spatial scales in a 236-year mixedwood chronosequence at Lake Duparquet, Quebec. Spatial relationships, species associations, and understory–overstory replacement patterns were studied using spatial statistics, patch indices, G tests, and transition matrices. Results of these analyses showed that shade-intolerant and shade-tolerant tree communities formed increasingly fine-grained patches in midsuccession. These fine-grained associations appear to be partly due to suppressed stems being released into a slowly thinning canopy and partly due to new recruitment of shade-tolerant conifers. In 1-ha plots, tree species richness and evenness peaked in 25-, 100-, and 400-m2 subplots during midsuccession. Forest cover type diversity also peaked in midsuccessional landscapes assessed using aerial photographs. The oldest 1-ha plot was dominated by monospecific patches of eastern white cedar (Thuja occidentalis L.), which was the most likely replacement for live and dead trees and the most abundant species in the numerous subplots that were occupied by trees smaller than 8 cm DBH. In spite of this dominance, long-lived paper birch (Betula papyrifera Marsh.) and residual fir (Abies balsamea (L.) Mill.) seedlings may maintain the mixedwood character of this stand into the future. The implications of our findings for stand management and conservation are discussed. [ABSTRACT FROM AUTHOR]

The paper presents research conducted following an investigation carried out by the Quebec Ministry of Transportation's Roadwork Service on the effects of tire width. The study looked at the impact of tires on the surface layer of pavement and the pavement behaviour as a result of this impact. The strains at a depth of 25 mm in the pavement, at the base of the pavement, and at the top of the subgrade were measured. Measurements were taken over two seasons representative of conditions prevailing in Quebec, in spring and in summer. Three parameters, the type of tire, the inflation pressure of the tire, and finally the load, were varied. The amplitude of damage produced by the circulation of a vehicle was then quantified to evaluate and compare the overall impact of various types of tires on pavement according to the various configurations. [ABSTRACT FROM AUTHOR]

The hydraulic conductivity of six compacted tills from northern Quebec with different grain-size distributions has been studied in saturated conditions in the laboratory. The results show that compaction conditions play an important role in hydraulic conductivity. When considering the hydraulic conductivities of specimens compacted at degrees of saturation greater than the optimum, there is a good correlation with the content of clay-size particles. This paper provides a good practical tool for evaluating preliminary hydraulic conductivity values of compacted tills from northern Quebec on the basis of their grain-size distribution and compaction conditions.Key words: till, hydraulic conductivity, grain-size distribution, compaction conditions.La conductivité hydraulique de six tills du nord québécois présentant des granulométries différentes a été étudiée en conditions saturées, en laboratoire. Les résultats montrent que les conditions de compactage jouent un rôle important dans la conductivité hydraulique qui en résulte. Lorsque l'on considère les conductivités hydrauliques mesurées sur des échantillons compactés à des degrés de saturation plus élevés que celui à l'optimum, on obtient une bonne corrélation avec le pourcentage de particules de dimensions argileuses. Cet article fournit donc un bon outil pratique pour une évaluation préliminaire de la conductivité hydraulique des tills du nord québécois sur la base de leur granulométrie et des conditions de compactage.Mots clés : till, conductivité hydraulique, granulométrie, conditions de compactage. [ABSTRACT FROM AUTHOR]

This paper concerns the petrogenesis of the 504 ± 3 Ma Mont Chagnon massif, the southern extension of the Orford ophiolite in the Quebec Appalachians. The evolution of this massif is summarized in three stages marked by different magmatic series. In the Late Cambrian, the onset of southeastern subduction of the Iapetus basin generated an immature oceanic island arc made up of light rare-earth-element-depleted tholeiites, now preserved in the massif as a portion of the intrusive crustal unit, the dyke complex, and part of the lower volcanic unit. A phase of arc splitting, and concomitant partial erosion of the crustal section, was shortly followed by the eruption of rhyolite genetically related to felsic and low-Ti dykes, and trondhjemite. The geochemistry of these magmas bear some similarities with boninitic series. We believe these liquids derived from the partial melting of the Iapetus amphibolitized oceanic crust, with that of its Laurentian-derived sediments and nearby peridotite, either found as a trapped sliver above the subducting slab or as the slab itself. The final stage, preserved in the massif as a part of the intrusive section, the upper volcanic rocks, and the late-stage dykes, represents the back-arc opening. An ocean-island component is involved in the back-arc related petrogenetic processes, producing magmas with compositions intermediate between arc tholeiites and enriched back-arc basin basalts. This is the first report that the Iapetus basin was locally closing as early as Late Cambrian in the southern Quebec area.Cet article traite de la pétrogenèse du massif du mont Chagnon, daté à 504 ± 3 Ma, qui est l'extension méridionale de l'ophiolite d'Orford dans les Appalaches du Québec. L'évolution de ce massif est résumée en trois étapes déterminées par des suites magmatiques différentes. Au Cambrien tardif, le début de la subduction vers le sud-est d'Iapetus a crée un arc insulaire océanique immature composé de tholéiites appauvries en terres rares légères, maintenant préservées dans le massif en tant qu'une portion de l'unité crustale intrusive, le complexe de dykes et une partie de l'unité volcanique inférieure. Une phase de division de l'arc, et l'érosion partielle concomitante de la section de la croûte, a été suivie de près par l'éruption de rhyolite, génétiquement reliée aux dykes felsiques et à ceux faibles en Ti, de même qu'à la trondhjémite. La géochimie de ces magmas comporte des similitudes avec les séries boninitiques. Nous croyons que ces liquides proviennent de la fusion partielle de la croûte amphibolitisée d'Iapetus, de ses sédiments dérivés du craton Laurentia et de la péridotite avoisinante, qui se trouvent soit coincés en tant qu'écaille au-dessus de la lithosphère en subduction ou soit en tant que lithosphère subductée elle-même. L'étape finale, préservée dans le massif en tant qu'une partie de la section intrusive, les roches volcaniques supérieures et les dykes tardifs, représente l'ouverture de l'arrière-arc. Une composante d'île océanique est impliquée dans les processus pétrogénétiques reliés à l'arrière-arc, produisant des magmas dont les compositions sont intermédiaires entre les tholéiites d'arc et les basaltes enrichis de bassins d'arrière-arc. Ceci est le premier rapport qu'Iapetus se refermait localement aussi tôt que le Cambrien tardif dans le sud du Québec.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Highlights the Peptide Receptors: From Gene to Therapy, an international multidisciplinary symposium held in Montreal, Quebec from July 29 to August 2, 2001. Contents of the symposium; Sponsors of the symposium; List of papers presented in the symposium.

Highlights the Peptide Receptors: From Gene to Therapy, an international multidisciplinary symposium held in Montreal, Quebec in 2001. Topics discussed in the symposium; List of papers presented in the symposium.

The preconsolidation pressure and overconsolidation ratio profiles are the most important factors related to the mechanical behaviour of clay deposits. They are interpreted on the basis of a limited number of laboratory tests, but the near-continuous information provided by the piezocone can allow local data to be extrapolated to an entire site. Numerous methods have been proposed for relating piezocone data to preconsolidation pressure and the overconsolidation ratio, but their validity is still uncertain. In this paper, nine methods are compared on the basis of data collected on 31 sensitive clay sites in Quebec whose preconsolidation pressure profiles are well known. Each method is briefly presented and the most promising are identified. The simplest method, which directly relates preconsolidation pressure to net tip resistance, also appears to be the most effective.Key words: clay, preconsolidation pressure, overconsolidation ratio, piezocone, correlations.Les profils de pression de préconsolidation et du rapport de surconsolidation constituent les éléments les plus importants en ce qui concerne le comportement mécanique des dépôts argileux. Leur évaluation se fait par un nombre limité d'essais de laboratoire, mais les données fournies par le piézocône de manière presque continue peuvent permettre une extrapolation à l'ensemble du site de ces données locales. De nombreuses méthodes ont été proposées pour corréler les données du piézocône et la pression de préconsolidation ou le rapport de surconsolidation mais leur validité est encore incertaine. Dans le présent article, neuf méthodes sont examinées à partir de données provenant de 31 sites d'argile sensible de la province du Québec pour lesquels les profils de pression de préconsolidation sont bien connus. Chaque méthode est brièvement présentée et les méthodes les plus intéressantes sont identifiées. Il semble que la relation entre la pression de préconsolidation et la résistance en pointe nette, qui est la plus simple, est aussi la plus efficace.Mots clés : argile, pression de préconsolidation, rapport de surconsolidation, piézocône, corrélations. [ABSTRACT FROM AUTHOR]

This paper presents the results of an extensive field investigation of several instrumented road sections in the Province of Quebec, Canada. Falling-weight deflectometer tests, static load tests on embedded plates at different depths, large dynamic cone penetration (DCP) tests, and piezocone tests (CPTU) were performed to study the mechanical response of the pavement. A correlation between elastic deformation modulus inferred from the plate load tests and DCP penetration index was obtained for nine different sites. A correlation between the equivalent elastic modulus of uniform subgrade soils and piezocone tip resistance was also established using data from the falling-weight deflectometer. A procedure for calculating the deflection basin for any pavement system placed over a more complex subgrade stratigraphy was proposed using these correlations. The proposed procedure was validated on two sites and its performance was adequate, since the calculated deflection basins agreed well with the measured deflection basins.Key words: penetration test, piezocone, deflection, pavement, in situ.Cet article présente les résultats d'une étude élaborée sur le terrain de plusieurs sections de route instrumentées dans la Province de Québec, Canada. Des essais au déflectomètre à masse tombante, de chargement statique sur des plaques enfouies à différentes profondeurs, de pénétration dynamique d'un gros cône (DCP), et de piézocône (CPTU) ont été réalisés pour étudier la réponse mécanique de la chaussée. Une corrélation entre le module de déformation élastique déduit des essais de chargement de plaques et l'indice de pénétration DCP a été obtenue pour neuf sites différents. Une corrélation entre le module élastique équivalent des sols de fondations uniformes et la résistance en pointe du piézocône a aussi été établie au moyen des données du déflectomètre à masse tombante. En partant de ces corrélations, on a proposé une procédure pour calculer le bassin de déflexion pour n'importe quel système de chaussée reposant sur une stratigraphie d'infrastructure complexe. La procédure proposée a été validée sur deux sites et sa performance a été adéquate puisque les bassins de déflexion calculés concordaient bien avec les valeurs mesurées.Mots clés : essai de pénétration, piézocône, déflexion, chaussée, in situ.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

To analyze the effects of strain rate and viscoplastic strain on consolidation of natural clay, this paper presents a nonlinear viscoplastic model in which viscoplastic behaviour is modeled by a unique effective stress (σ'[sub v] ) – viscous strain (ℇ[sub v] ) – viscous strain rate (ℇ[sup ·] [sub v] ) relationship. The proposed model can consider the effects of strain rate and viscoplastic strain on consolidation, to take into account the difference in strain rate between laboratory and field conditions, and the combined processes of generation and dissipation of pore pressure during consolidation. This model can also predict the behaviour of clay during stepwise loading, constant rate of strain, and relaxation of effective stress. The predicted values using numerical analysis are compared with measured values in laboratory tests and in situ, under an embankment built on soft clay at Berthierville, Quebec. It is possible to estimate the consolidation behaviour of natural clay with reasonable accuracy using the proposed nonlinear viscoplastic model.Key words: consolidation, soft clay, strain rate, viscoplastic, relaxation.Dans le but d'analyser les effets de la vitesse de déformation et de la déformation viscoplastique sur la consolidation de l'argile naturelle, cet article présente un modèle viscoplastique non linéaire dans lequel le comportement est modélisé par une relation unique contrainte effective-déformation visqueuse-vitesse de déformation visqueuse σ'[sub v] – ℇ[sub v] – ℇ[sup ·] [sub v] . Le modèle proposé peut prendre en considération les effets de la vitesse de déformation et de la déformation viscoplastique sur la consolidation pour tenir compte de la différence dans les vitesses de déformation entre les conditions en laboratoire et sur le chantier, de même que les processus combinés de génération et de dissipation de la pression interstitielle durant la consolidation. Ce modèle peut aussi prédire le comportement de l'argile en incluant le chargement par étape, la vitesse de déformation constante, et la relaxation de la contrainte effective. Les valeurs prédites au moyen de l'analyse numérique sont comparées avec celles mesurées dans les essais en laboratoire et in situ sous un remblai construit sur de l'argile molle à Berthierville, Québec. Il est possible d'estimer le comportement en consolidation de l'argile naturelle avec une précision raisonnable au moyen du modèle viscoplastique non linéaire proposé. Mots clés : consolidation, argile molle, vitesse de déformation, viscoplastique, relaxation.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

This article presents information about the articles published in the August 1, 2004 issue of the journal "Canadian Journal of Botany." This issue is a collection of invited, peer-reviewed symposium papers from the 4th International Conference on Mycorrhizae held in Montreal, Quebec, in August 2003.