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This installment of 'Atomic Perspectives' is the second in a series describing the educational components and processes necessary in teaching and learning the technique of X-ray fluorescence (XRF) spectroscopy. Although [...]

This column installment is the first in a series describing the educational components and processes necessary in learning the technique of X-ray fluorescence (XRF) spectroscopy. Here, we discuss the main [...]

In theory, linkages between hierarchical forest management planning levels ensure coherent disaggregation of long-term wood supply allocation as input for short-term demand-driven harvest planning. In practice, these linkages may be ineffective, and solutions produced may be incoherent in terms of volume and value-creation potential of harvested timber. Systematic incoherence between planned and implemented forest management activities may induce drift of forest system state (i.e., divergence of planned and actual system state trajectories), thus compromising credibility and performance of the forest management planning process. We describe hierarchical forest management from a game-theoretic perspective and present an iterative two-phase model simulating interaction between long- and short-term planning processes. Using an illustrative case study, we confirm the existence of a systematic drift effect, which we attribute to ineffective linkages between long- and short-term planning. In several simulated scenarios, the planning process fails to ensure long-term wood supply sustainability, fails to reliably meet industrial fiber demand over time, and exacerbates incoherence between wood supply and fiber demand over several planning iterations. We show that manipulating linkages between long- and short-term planning processes can reduce incoherence and describe future work on game-theoretic planning process model formulations that may improve hierarchical planning process performance. Resume: En theorie, les systemes de planification hierarchiques integrent des mecanismes de liaison efficaces, assurant ainsi une desaggregation coherente de l'attribution de volumes aux usines lors de la planification detaillee des operations de recolte. En pratique, les mecanismes de liaison entre la planification a long-et a court-terme peuvent etre inefficaces, menant donc a des plans incoherents en termes du volume recolte, de la representation des essences, et du potentiel de creation de valeur des billes livrees aux usines. Cette incoherence entre la planification et l'execution de la recolte peut induire une derive systematique de l'etat du systeme forestier (c.-a-d. divergence entre les trajectoires projetees et realisees), compromettant donc la credibilite et la performance du processus de planification de l'amenagement forestier. Nous decrivons le processus de planification forestiere en termes de la theorie du jeu, et nous simulons l'interaction entre la planification de l'approvisionnement et la planification de la recolte a l'aide d'un modele iteratif a deux phases. Nous presentons une etude de cas, et nous montrons l'existence d'un effet de derive systematique, que nous attribuons a l'innefficacite des mecanismes reliant la planification long- et court-terme. Nous montrons qu'il est possible d'ameliorer la coherence des plans en manipulant les mecanismes de liaison, et proposons des avenues de recherche futures pouvant potentiellement ameliorer la performance du processus de planification hierarchique a l'aide de nouvelles formulations de modeles bases sur la theorie du jeu., 1. Introduction Hierarchical forest management (HFM) on public land may currently be failing on two levels. At the top level, HFM may not be providing credible assurance of long-term sustainability [...]

We evaluated spruce budworm (Choristoneura fumiferana (Clem.)) outbreak effects in nine study areas (60-86 ha each) located in the boreal forest of eastern Quebec (Canada). In each area, spruce budworm outbreak effects were measured from vegetation plots, dominant canopy and understory tree age structures, retrospective analysis of aerial photographs, defoliation records, and host tree growth reductions (dendrochronology). Large-scale synchronous outbreaks were detected across the region around the years 1880, 1915. 1950. and 1980. Overall, contrarily to what was expected for a region where host species (balsam fir (Abies balsamea (L.) Mill.). Picea spp.) content is relatively high, these spruce budworm outbreaks seemed to have a relatively minor influence on stand dynamics, with the exception of the most recent outbreak ( 1980). This outbreak resulted in major stand mortality in the southern part of the region and favored the establishment of extensive tracts of young even-aged stands with few residual mature trees. This very abrupt increase in outbreak severity compared with earlier outbreaks, perhaps due to climatic or random factors, suggests that historical trends in successive outbreak severity should be extrapolated very cautiously and that the study of several outbreak cycles is needed to establish a range of natural variability that can be used to develop an ecosystem forest management strategy. Resume: Nous avons evalue les effets des epidemics de tordeuse des bourgeons de l'epinette (Choristoneura fumiferana (Clem.)) dans neuf aires d'etude (de 60-86 ha chaque) situees dans la foret boreale de Test du Quebec, au Canada. Dans chaque aire d'etude. les effets des epidemies de tordeuse des bourgeons de l'epinette ont ete mesures a partir de pincettes de vegetation, de la structure d'age des arbres de la canopee dominante et du sous-bois. d'une analyse retrospective de photographies aeriennes, de releves de defoliation et des reductions de croissance des arbres botes (dendrochronologie). Des epidemies synchrones out ete detectees sur I'ensemble de la region autour des annees 1880. 1915, 1950 et 1980. Contrairement a ce qui etait anticipe dans une region ou les especes botes (sapin baumier (Abies balsamea (L.) Mill.), Picea spp.) sont relativement abondantes. ces epidemies de tordeuse des bourgeons de l'epinette semblent avoir eu un impact relativement limite sur la dynamique des peuplements. a 1'exception de l'epidemie la plus recente (1980). Cette epidemie a cause une forte mortalite dans les peuplements situes dans la partie sud de la region et a favorise I'etablissement, sur de vastes etendues, de jeunes peuplements equiennes contenant peu d'arbres matures residuels. La hausse tres abrupte de l'in-tensite de cette epidemie comparativement aux epidemies precedentes est probablement attribuable a des facteurs climati-ques ou aleatoires et indique que les tendances historiques de I'intensite des epidemies successives devraient etre extrapolees avec beaucoup de prudence. Ce resultat indique aussi qu'il faut etudier plusieurs cycles epidemiques pour defi-nir les limites de la variabilite naturelle qui peuvent etre utilisees pour mettre au point une strategic d'amenagement fores-tier ecosystemique. [Traduit par la Redaction], Introduction Spruce budworm (Choristoneura fumiferana (Clem.); SBW) outbreaks are one of the most important large-scale disturbances in the boreal and subboreal forests of eastern North America (MacLean 2004). These outbreaks [...]

The frequency of stand-replacing windthrow has rarely been evaluated over large spatio-temporal scales in boreal forests. This study examines stand-replacing windthrow that occurred within a forested area of 3 061 000 ha, both at the regional scale and at the scale of individual windthrow events. We specifically examined windthrow that covered at least 5 ha and for which mortality affected >75% of pre-windthrow canopy cover. At the regional scale, we found that windthrow affected, on average, 0.0255% of the area per year between 1971 and 2000. Logistic regressions indicate that stand age was the most important predictor variable at this scale, with severe windthrow less likely to occur in relatively young stands ( La frequence des chablis entrainant le remplacement des peuplements a rarement ete estimee a grande echelle spatio-temporelle en foret boreale. Nous avons etudie les chablis entrainant le remplacement des peuplements qui sont survenus sur une superficie forestiere de 3 061 000 ha a l'echelle regionale et a l'echelle des episodes individuels de chablis. Nous n'avons considere que les chablis couvrant au moins 5 ha et ayant cause la mortalite de plus de 75 % du couvert initial du peuplement. A l'echelle regionale, la moyenne annuelle de la superficie affectee par des chablis etait de 0,0255 % entre 1971 et 2000. Des regressions logistiques indiquent que la variable predictive la plus importante a l'echelle regionale etait l'age des peuplements avec de plus faibles probabilites d'occurrence de chablis severes dans les peuplements relativement jeunes ( [Traduit par la Redaction], 1. Introduction The types of natural disturbances that are the most often mentioned in the boreal forest are fire and insect outbreaks. Windthrow is considered an important disturbance at the [...]

Abstract: We evaluated geographic variations in mean fire return intervals and postfire forest succession within a 66497 [km.sup.2] land area located in the eastern Quebec boreal forest. Fire return intervals [...]

Abstract: The effects of 20th century spruce budworm (Choristoneura fumiferana (Clem.)) outbreaks on forest dynamics was examined in the southern and northern parts of the mixedwood forest zone in central [...]

Many modelling approaches have been developed to project climate change impacts on forests. By analysing 'comparable' yet distinct variables (e.g. productivity, growth, dominance, biomass, etc.) through different structures, parameterizations and assumptions, models can yield different outcomes to rather similar initial questions. This variability can lead to some confusion for forest managers when developing strategies to adapt forest management to climate change. In this study, we standardized results from seven different models (Habitat suitability, trGam, StandLEAP, Quebec Landscape Dynamics, PICUS, LANDIS‐II and LPJ‐LMfire) to provide a simple and comprehensive assessment of the uncertainty and consensus in future performance (decline, status quo, improvement) for six tree species in Quebec under two radiative forcing scenarios (RCP 4.5 and RCP 8.5). Despite a large diversity of model types, we found a high level of agreement (73.1%) in projected species' performance across species, regions, scenarios and time periods. Low agreements in model outcomes resulted from small dissensions among models. Model agreement was much higher for cold‐tolerant species (up to 99.9%), especially in southernmost forest regions and under RCP 8.5, indicating that these species are especially sensitive to increased climate forcing in the southern part of their distribution range. Lower agreement was found for thermophilous species (sugar maple, yellow birch) in boreal regions under RCP 8.5 mostly as a result of the way the different models are handling natural disturbances (e.g. wildfires) and lags in the response of populations (forest inertia or migration capability) to climate change. Agreement was slightly higher under high anthropogenic climate forcing, suggesting that important thresholds in species‐specific performance might be crossed if radiative forcing reach values as high as those projected under RCP 8.5. We expect that strong agreement among models despite their different assumptions, predictors and structure should inspire the development of forest management strategies to be better adapted to climate change. [ABSTRACT FROM AUTHOR]

Tree-ring time series provide long-term, annually resolved information on the growth of trees. When sampled in a systematic context, tree-ring data can be scaled to estimate the forest carbon capture and storage of landscapes, biomes, and—ultimately—the globe. A systematic effort to sample tree rings in national forest inventories would yield unprecedented temporal and spatial resolution of forest carbon dynamics and help resolve key scientific uncertainties, which we highlight in terms of evidence for forest greening (enhanced growth) versus browning (reduced growth, increased mortality). We describe jump-starting a tree-ring collection across the continent of North America, given the commitments of Canada, the United States, and Mexico to visit forest inventory plots, along with existing legacy collections. Failing to do so would be a missed opportunity to help chart an evidence-based path toward meeting national commitments to reduce net greenhouse gas emissions, urgently needed for climate stabilization and repair. [ABSTRACT FROM AUTHOR]

Climate change is causing northward shifts in species ranges. For mobile species such as insects, this will increase their access to forest ecosystems where in the past their presence and [...]

This article develops an experimental platform to select production planning policy in demand-driven wood remanufacturing industry. This industry is characterised by divergent co-production, alternative processes, a make-to-order philosophy and short order cycle times. Under such complex characteristics, the selection of an efficient production plan is a complex task. Previous work has failed to address all the industrial characteristics encountered in wood remanufacturing mills. After defining key performance indicators (KPIs) to measure the production plan efficiency, our methodology uses a periodic re-planning strategy based on a rolling horizon. Then, mixed-integer programming models are formulated leading to different planning approaches. Finally, the resulting decision framework is experimented to prescribe the best planning policy based on the selected KPI. Each production planning is characterised by its planning approach and factors related to the re-planning interval and the planning horizon length. Simulations are conducted using multiple best subset selections combined with an experimental design approach. Using industrial data from a wood remanufacturing mill in Eastern Canada, results indicate that the manufacturing mill should use a planning approach that minimises cost, while utilising the full system capacity. Results also quantify the benefit of using lower re-planning intervals and higher planning horizons. [ABSTRACT FROM AUTHOR]