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Wood discoloration was investigated in 721 paper birch (Betula papyrifera Marsh.) trees from 146 sites across the managed forest of Quebec, Canada. Discoloration was present at breast height in 85% of trees, but its impact was limited in terms of tree basal area and volume, with proportions of 6.4% and 3.6%, respectively. These two measures were strongly correlated. Discoloration changed wood appearance but had no effect on microfibril angle and modulus of elasticity. Discolored wood was nevertheless denser, probably due to the accumulation of colored extractives. Predictive models were also developed and applied to 415 711 paper birch trees from 51 689 inventory plots across the province to study regional variation. Higher proportions of discolored basal area were obtained in the southwestern areas of the province where the climate is warmer and drier. In these areas, paper birch trees are larger and, likely, support bigger branches which can cause larger columns of discoloration when broken. Lower proportions were found in eastern regions where snowfall is more abundant. Smaller, more flexible branches in trees growing in these areas could explain this result. This study confirms the feasibility of large-scale mapping of wood discoloration in standing trees based on forest inventory and climate data. [ABSTRACT FROM AUTHOR]

Presents a study that examined the role of papermill sludge in the organic forest carbon cycle of paper products. Prediction on the global production of papermill sludge; Impact of paper production and wastepaper recycling trends on the woody carbon components of sludge; Implications of the organic content and carbon content of sludge for dealing with disposal policy and problems.

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]

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]

Forests are the locus of conflict in Canada, where the rights and interests of Indigenous peoples can collide with those of the province (Crown) and the forest industry. Efforts to achieve "forest justice" — or sufficient forest rights to meet the self-governance goals of Indigenous peoples, and in ways that ensure collective resilience — have typically been driven by the principle of reconciliation. In this paper, these "forest justice" efforts were examined through a tripartite justice theory, involving recognition, representation, and redistribution pathways. This paper documents that recognition involves Crown efforts to recognize Indigenous peoples' forest rights, including ownership, and access and use rights; representation includes improved participation in forest governance; and redistribution covers the allocation of timber harvesting rights and forest lands to Indigenous peoples. This study documents that the bulk of "forest justice" activity is focused on the redistribution of timber harvesting licences, the volume of which has doubled over the last two decades. These three paths to justice must all be pursued together to deliver "forest justice", and to move towards "reconciliation in the woods". Recommendations are offered to support forest justice in practice. [ABSTRACT FROM AUTHOR]

In several gymnosperm tree species of the circumboreal forest, reproductive development is closely associated with the accumulation of degree-days during the growing season. We wanted to verify whether this pattern holds for a widespread angiosperm species such as paper birch (Betula papyrifera Marsh), a broadleaf tree distributed throughout the North American boreal forest. Stations to simultaneously measure the thermal sum (degree-days > 5 °C, DD) and the reproductive development (anatomical development and seed germination) were installed in four sites along an altitudinal thermal gradient totalling 541 m a.s.l. in the eastern Appalachian Mountains (Canada). In 2004, sites 1, 2, 3 and 4, received 973, 1099, 1266 and 1359 DD, respectively. A strong relationship was found between thermal sum and reproductive development (anatomical development: r2 > 0.90; seed germination r2 > 0.72). This relationship seems to be based on the absolute value of heat-sum received because (i) rates of reproductive development are twice as high in colder sites (1 and 2) than in warmer sites (3 and 4), and (ii) total seed germination did not differ among the sites. Along with this, we noted a lesser production of full seeds in colder sites, coupled with a higher success of germination in the coldest site (site 1), which appears to be a mechanism of phenotypic adaptation to cold. [ABSTRACT FROM AUTHOR]

In recent years, increasing attention has been drawn to improving productivity in logging passages while reducing negative impact on soil and water. The position of landings and extraction routes is crucial in these efforts, as it has a huge impact on efficient and sustainable forwarder passages. In this paper, we propose a two-phase approach to identify the best possible landing locations integrated with log extraction route design. The first phase identifies potential landing zones adjacent to forest roads. It considers practical restrictions such as slopes, stoniness, and closeness to infrastructure. The second phase uses an optimization model to evaluate the potential impact of each zone and aggregate zones, selecting one or two complete landings. This model is a relaxation of a formulation for an extraction route design; it is used to minimize a weighted objective of the total driving distance, avoid steep terrains and impact on soil and water. The proposed approach has been tested on a set of harvest areas in southern Sweden. The results not only show the potential to identify feasible landing zones but also identify a shorter driving distance and hence lower contractual cost with optimized positioning. The possibility to increase efficiency in forest operations by performing scenario analysis and thus forwarding distances with different landing sites is among the results. [ABSTRACT FROM AUTHOR]

Ecological forestry is based on the idea that forest patterns and processes are more likely to persist if harvest strategies produce stand structures, return intervals, and severities similar to those from natural disturbances. Taylor et al. (2020) reviewed forest natural disturbance regimes in Nova Scotia, Canada, to support implementation of ecological forestry. In this follow-up paper, we (i) review the use of natural disturbance regimes to determine target harvest rotations, age structures, and residual stand structures; and (ii) describe a novel approach for use of natural disturbance regimes in ecological forestry developed for Nova Scotia. Most examples of ecological forestry consider only the local, dominant disturbance agent, such as fire in boreal regions. Our approach included: (i) using current ecological land classification to map potential natural vegetation (PNV) community types; (ii) determining cumulative natural disturbance effects of all major disturbances, in our case fire, hurricanes, windstorm, and insect outbreaks for each PNV; and (iii) using natural disturbance regime parameters to derive guidelines for ecological forestry for each PNV. We analyzed disturbance occurrence and return intervals based on low, moderate, and high severity classes (<30, 30–60, and >60% of biomass of living trees killed, respectively), which were used to determine mean annual disturbance rates by severity class. Return intervals were used to infer target stand age-class distributions for high, moderate, and low severity disturbances for each PNV. The range of variation in rates of high severity disturbances among PNVs was from 0.28%·year–1 in Tolerant Hardwood to 2.1%·year–1 in the Highland Fir PNV, equating to return intervals of 357 years in Tolerant Hardwood to 48 years in Highland Fir PNVs. As an example, this return interval for the Tolerant Hardwood PNV resulted in target rotation lengths of 200 years for 35% of the PNV area, 500 years for 40%, and 1000 years for 25%. The proposed approach of determining natural disturbance regimes for PNV communities and calculating target disturbance rates and corresponding harvest rotation lengths or entry times appears to be a feasible method to guide ecological forestry in any region with a strong ecological land classification system and multiple disturbance agents. [ABSTRACT FROM AUTHOR]

The aim of the present synthesis paper was to determine whether concentration changes and net release of manganese (Mn), as related to accumulated litter mass loss, are related to initial Mn concentration, mean annual temperature (MAT), mean annual precipitation (MAP), and tree genus or species. We also examined whether limit values for decomposition are related to initial litter Mn concentration, MAT, and MAP. We compiled 84 foliar litter decomposition studies, conducted mainly in boreal and temperate forest ecosystems, for which Mn dynamics had been well documented. Manganese concentration and amount were related to accumulated litter mass loss at each sampling time for each single study, as well as for ( i) all studies combined ( n = 748) and ( ii) for species groups viz. Norway spruce ( Picea abies (L.) Karst.) ( n = 284), pine ( Pinus) species ( n = 330), and deciduous species ( n = 214). The changes in Mn concentration with accumulated mass loss followed quadratic functions showing significantly higher Mn concentrations for Norway spruce vs. Scots pine ( Pinus sylvestris L.) ( p < 0.0001) and vs. deciduous species ( p < 0.01), as well as significantly higher for deciduous species vs. Scots pine ( p < 0.0001). Manganese release rates were different among the three species groups ( p < 0.001). Still, rates were related to initial Mn concentrations ( p < 0.001) for all litter types combined and for the three species groups. Norway spruce released Mn more slowly than pine and deciduous species. Rates were related to climatic factors for litter of Norway spruce and deciduous species. Limit values for all litter and for pine species separately were related to Mn ( p < 0.001) and MAT ( p < 0.001). For Norway spruce, limit values were related to MAT ( p < 0.001) and MAP ( p < 0.01). It appears that Norway spruce litter retains Mn more strongly in the litter structure, producing humus richer in Mn than does litter of pine and deciduous species. [ABSTRACT FROM AUTHOR]

Climate-smart forestry (CSF) is considered a promising approach for climate change adaptation and mitigation strategies, as highlighted in several European policy documents. This paper describes a prospective approach to introducing an incentive-based scheme to facilitate the implementation of CSF through a case study in Iceland. It is argued that the payments for ecosystem services (PES) scheme allows for effective CSF management and long-term sustainability if introduced in compliance with local, cultural, and social values. In a case study of an Icelandic afforestation programme, we conducted an institutional analysis of the PES scheme and assessed its effect on the sustainable provision of forest ecosystem services for the long term. We provide preliminary findings on the application of CSF in the 30-year-old Icelandic afforestation programme scheme. The perspectives of forest and policy experts, as well as local farmers participating in the scheme, were crucial for assessing the effectiveness of PES scheme performance in Iceland. [ABSTRACT FROM AUTHOR]

Rehabilitation of cutover stands is often a management objective of landowners who desire improved stand conditions and increased value from future harvest revenues. We evaluated crop tree growth response and quality following precommercial rehabilitation treatments in mixedwood stands degraded through repeated exploitive cutting in Maine, USA. Treatments included control (no rehabilitation), moderate rehabilitation (crop tree release), and intensive rehabilitation (crop tree release plus timber stand improvement). Paper birch (Betula papyrifera Marsh.), red spruce (Picea rubens Sarg.), and eastern hemlock (Tsuga canadensis (L.) Carriere) crop tree diameter increments 0 to 9 years after treatment were greater following rehabilitation than in the control. Diameter increment did not differ between intensities of rehabilitation for any species. For conifers in the lower strata, crop tree height growth and change in crown length were negatively correlated with basal area in larger trees. The occurrence of epicormic branches on paper birches was greater in the rehabilitation treatments than the control. However, most epicormic branches occurred above the height corresponding to the first sawlog. These findings indicate that rehabilitation of mixedwood stands with similar characteristics can result in improved growth of crop trees without jeopardizing the quality of the lower bole in paper birches. [ABSTRACT FROM AUTHOR]

This paper describes the development and implementation of a model to measure and compare transaction costs in situations of multiple land use, where interdependence prevails between the agents — thus actions of one agent affects others. Transaction costs typically occur in situations where limited resources are used by more than one agent and bargaining of the use is conducted to mitigate conflict. The model of the paper is empirically tested on one such situation: forestry and reindeer husbandry, which is pursued in northern Sweden where transaction costs occur in common land use as a result of consultations. The results indicate that transaction costs are unevenly distributed between the two agents, where reindeer husbandry carries the highest costs, resulting in uneven power relations. Transaction costs are driven by the presence of Land Use Plans of reindeer husbandry, interestingly enough driving the costs in different directions for the two agents. The model illustrates the elements of transaction costs in a common pool resource situation, and the results are not only useful for this specific situation in policymaking, but also for other similar situations. [ABSTRACT FROM AUTHOR]

Sustaining the structure, function, and services provided by forest ecosystems in the face of changing climate and disturbance regimes represents a grand challenge for forest managers and policy makers. To address this challenge, a range of adaptation approaches have been proposed centered on conferring ecosystem resilience and adaptive capacity; however, considerable uncertainty exists regarding how to translate these broad and often theoretical adaptation frameworks to on-the-ground practice. Complicating this issue has been movement away, in some cases, from other recent advances in forest management, namely ecological silviculture strategies that often focus on restoration. In this paper, we highlight the areas of compatibility and conflict between these two frameworks by reviewing the four principles of ecological silviculture (continuity, complexity and diversity, timing, and context) from the perspective of global change adaptation. We conclude that given many commonalities between the outcomes of ecological silviculture and conditions conferring adaptive capacity, the four principles remain a relevant starting point for guiding operationalization of often theoretical adaptation strategies. [ABSTRACT FROM AUTHOR]

Traditionally, forest management has focused on forestry-related practices whereas other industries have been managed separately. Forest management requires the integration of all natural resource development activities, along with other anthropogenic and natural forest disturbances (e.g., climate change, pollution, wildfire, pest disturbance) to understand how human activities can change forested ecosystems. The term cumulative effects has been used to describe these attempts to integrate all disturbances to develop an understanding of past, current, and future impacts on environmental, social, and economic components of the system. In this review, we focus on the science required to understand the past, current, and future impacts of the cumulative effects of anthropogenic and natural disturbances on forested ecosystems or their components. We have primarily focused on the terrestrial system with an emphasis on northern forests in Canada. Our paper is not intended to be a comprehensive review of all cumulative effects science but a synthesis of the challenges and approaches currently being used. Central repositories were identified as an approach to deal with issues of availability of remotely sensed data on anthropogenic and natural disturbances. Data integration projects, open data, and well-designed large-scale data collection efforts are needed to provide sufficient data on environmental responses to cumulative effects. As well, large-scale integrated, modularized ecosystem models are needed to bring stressor and environmental response data together to explore responses to, and interactions between, multiple stressors to project these effects into the future and to identify future data collection needs. [ABSTRACT FROM AUTHOR]

The recent economic downturn severely affected the US forest sector from a macroeconomic perspective but little is known about changes in firm-level performance. In this study we investigate the changes in financial, social and environmental performance of forest sector firms during a period that approximately corresponds to the downturn. We also assess industry dynamism and industry's view about social and environmental responsibility as a competitive tool. We conducted a national survey of wood, furniture, and paper companies. Approximately 60% of our respondents reported a decline in financial performance during the downturn. With respect to social and environmental performance, customer-oriented actions show mixed trends, employee matters remained somewhat unaltered, community engagement significantly decreased, and engagement in environmental activities significantly increased. Respondents view their operating business environment as highly dynamic and difficult and they do not view engagement in social and environmental responsibility activities leading to either financial or nonfinancial benefits. [ABSTRACT FROM AUTHOR]

Wood density, an important parameter for evaluating forest biomass productivity and wood product quality control, is influenced by a complex combination of variables of forest plantations, including environmental conditions and the management practices adopted. In this paper, we demonstrate that three site variables (annual rainfall, temperature, and soil texture) and 10 plantation variables (e.g., age and genetic material) are associated with basic wood density (evaluated in two situations: with and without bark) in 936 trees of different species of Eucalyptus L'Hér across five distinct edaphoclimatic regions in Brazil. A canonical correlation analysis was used to identify the most contributory variables affecting wood density. The variables globally associated with high basic wood densities were, in order of importance, the genetic material and area per tree (both under direct control of plantation managers), as well as mean annual temperature and soil texture of the site. These results confirmed the advantage of using clonal material (instead of seedling origin material) planted in larger spacings in sites with higher mean annual temperatures and clayey soils to obtain higher basic wood densities. Conversely, low basic wood densities were associated with high-productivity sites, higher rainfall, and plantations with a higher basal area per stem in second rotation. [ABSTRACT FROM AUTHOR]

The increased pressure on timber supply due to a reduced forest land base urges the development of new approaches to fully capture the value of forest products. This paper investigates the effects of knowing the position of knots on lumber volume, value, and grade recoveries in curve sawing of 31 white spruce (Picea glauca (Moench) Voss) and 22 jack pine (Pinus banksiana Lamb.) trees. Internal knot position was evidenced by X-ray computed tomography (CT) imaging, followed by the application of a knot-detection algorithm allowing log reconstruction for use as input in the Optitek sawing simulation software. Comparisons of the three levels of sawing optimization (sweep up, shape optimized, and knot optimized) revealed that considering internal knots before log sawing (e.g., knot optimized) generated 23% more lumber value for jack pine and 15% more for white spruce compared with the traditional sweep-up sawing strategy. In terms of lumber quality, the knot-optimized strategy produced 38% more pieces of grade No. 2 and better in jack pine and 15% more such pieces in white spruce compared with the sweep-up strategy. These results indicate a great potential to increase manufacturing efficiency and profitability by implementing the CT scanning technology, which should aid in developing a strong bioeconomy based on an optimized use of wood. [ABSTRACT FROM AUTHOR]

Do fast-growing trees produce lower density wood? To determine the relationship between growth rate and wood density in plantation-grown aspen (Populus tremuloides Michx.), 199 trees in 20 clones were sampled from a 15-year-old clonal trial. This study found no evidence that fast-grown trees produce less dense wood. Phenotypic and genetic correlations between height, diameter, volume, and biomass were all high and significant. Wood density was not correlated with height or volume, but there were small and significant (p ≤ 0.05) positive phenotypic correlations with stem diameter. Genetic correlations between breast-height wood density and all three growth measures (height, DBH, and volume) were not significantly different from zero. This suggests that selection for growth will not influence wood density and vice versa. This paper discusses some possible reasons for the contradictions in the literature about the relationship between growth rate and wood density in aspen. The anatomy of juvenile or core wood is different from that of mature wood, and the relationship between density and growth rate also differs. The changing relative proportion of juvenile core wood with tree size may explain many of the apparent contradictions. [ABSTRACT FROM AUTHOR]

Public advisory committees (PACs) are a dominant form of public participation in Canada's Crown forests, providing a venue in which members of the local public can engage and influence sustainable forest management decision-making. In this paper, we examine the experiences of Indigenous participants (relative to non-Indigenous participants) concerning the success of PAC processes. We focus on issues of fairness, equity, and inclusion of Indigenous voices along with an assessment of forest values diversity. Findings from surveys in 2004 and 2016 indicate statistically significant differences between Indigenous and non-Indigenous PAC members regarding their forest values and their evaluation of the success of PAC processes. This work draws attention to the relative experiences of survey participants and the identification of persistent challenges associated with public engagement over the last two decades. Policy recommendations include substantial changes to how we define and measure sustainable forest management in Canada. [ABSTRACT FROM AUTHOR]

Contemporary fire regimes of Canadian forests have been well documented based on forest fire records between the late 1950s to 1990s. Due to known limitations of fire datasets, an analysis of changes in fire-regime characteristics could not be easily undertaken. This paper presents fire-regime trends nationally and within two zonation systems, the homogeneous fire-regime zones and ecozones, for two time periods, 1959–2015 and 1980–2015. Nationally, trends in both area burned and number of large fires (≥200 ha) have increased significantly since 1959, which might be due to increases in lightning-caused fires. Human-caused fires, in contrast, have shown a decline. Results suggest that large fires have been getting larger over the last 57 years and that the fire season has been starting approximately one week earlier and ending one week later. At the regional level, trends in fire regimes are variable across the country, with fewer significant trends. Area burned, number of large fires, and lightning-caused fires are increasing in most of western Canada, whereas human-caused fires are either stable or declining throughout the country. Overall, Canadian forests appear to have been engaged in a trajectory towards more active fire regimes over the last half century. [ABSTRACT FROM AUTHOR]

The challenges faced recently by the North American forest products industry have forced it to review many of its key operations. Implementing logistics centers for such a context may therefore help in allocating the wood fibre more efficiently and in reducing sorting and transportation costs. This paper aims to better understand the interaction between a forest logistics center and a complex forest network while exploring the business environment favoring the use of such a structure. A profit maximization model is proposed and applied to a real case in the Mauricie region in Quebec, Canada. A total of 18 groups of scenarios are tested, based on the use of a sort yard and of backhauling. Results show that a logistics center already in operation adds $0.52 in profits for each cubic metre of wood available for harvest (over 2 580 411 m3 per year) for the network under study ($1.4 million annually). A sensitivity analysis also highlights that higher prices and sorting error rates have the greatest impact on the logistics center's profitability. [ABSTRACT FROM AUTHOR]

Cross-sector collaboration has gained attention from researchers in different fields of science in recent years because it represents significant business potential for forest companies to work with sectors possessing a more positive demand outlook, including those facing increasing pressure to detach from oil derivatives. Despite this, there is a lack of research regarding company-level, cross-sector collaboration in the forest-sector literature. This paper seeks to enhance the understanding of the cross-sector collaboration concept in the forest-sector literature and explore alternatives for forest companies to collaborate with other industries, rather than to compete. A systematic literature review is conducted to explore the relevance of cross-sector collaboration in the forest industry. Furthermore, the main drivers, benefits, and challenges of collaboration in the forest industry are identified. Results show that the literature has emphasized the importance of cross-sector collaboration for forest companies, but little empirical work has been done regarding the link between forest companies and other industrial sectors. Cost reduction, competitiveness, and environmental sustainability are among the principal drivers and benefits. Forest business culture, lack of trust, and lack of parameters to evaluate costs and savings generated are key challenges to forest companies implementing cross-sector collaboration. [ABSTRACT FROM AUTHOR]

Quantifying the age characteristics of a forest can provide valuable information about the forest’s impact on the environment. For instance, the age of a forest can affect the ecosystem’s carbon exchange, soil enzyme activity, and biodiversity. In this paper, we investigate the use of different sampling methods to estimate the age characteristics of three simulated ponderosa pine (Pinus ponderosa Dougl. ex P. Lawson & C. Lawson) forests having different spatial and age patterns. This includes estimating the mean tree age and the age-class distribution of the trees in the forest. The trees in the sample are selected using k-tree sampling, fixed-radius plot sampling, or variable-radius plot sampling, and we compare the properties of the resulting estimators via design-based and model-based approaches. Analyses of the different sampling methods applied to the three forests suggest that the estimator associated with k-tree sampling, with the addition of a few extra trees per plot, is feasible for forests having a spatially mosaic or random spatial pattern. The estimator associated with fixed-radius plot sampling performed well for the forest having a clustered spatial pattern. [ABSTRACT FROM AUTHOR]

In this paper, we present an approach employing multiobjective optimization to support decision making in forest management planning under risk. The primary objectives are biodiversity and timber cash flow, evaluated from two perspectives: the expected value and the value-at-risk (VaR). In addition, the risk level for both the timber cash flow and biodiversity values are included as objectives. With our approach, we highlight the trade-off between the expected value and the VaR, as well as between the VaRs of the two objectives of interest. We employ an interactive method in which a decision maker iteratively provides preference information to find the most preferred management plan and learns about the interdependencies of the objectives at the same time. The method is illustrated with a case study in which biodiversity is assessed through an index calculated from the characteristics of the forest. Uncertainty is included both through modifying the input data according to the accuracy of current inventory methods and through growth model errors. This uncertainty is described using a set of 25 scenarios. Involving multiple components of risk is a highly relevant approach in multiobjective forestry; however, estimation of the uncertainty of biodiversity needs further attention. [ABSTRACT FROM AUTHOR]

The article presents the emerging forest bioeconomy as an integrated, multi-product industrial ecosystem, where the traditional pulp mills allocate the use of side streams to independent biochemical companies manufacturing bioproducts in the vicinity of the pulp mills. Topics include the biochemical benefit from the proximity by receiving wood-based side streams at lower costs, and at the same time, and the pulp mills benefit from having a new source of revenue from selling side streams.

The USDA Forest Service, the Canadian Forest Service, and US and Canadian forest products industries are committed to the principles of sustainable forestry with a major focus on protecting soil productivity. The USDA Forest Service has developed and adopted soil quality standards to evaluate the effects of forest use and management activities on forest soils and, if necessary, prescribe remedial or preventive actions to avoid adverse impacts on soil productivity. Similarly, the Canadian Forest Service has adopted a series of criteria and indicators with which to monitor the impacts of management on soil resources. The policies of both public agencies reflect the recommendations of the Montréal Process Working Group (1999). Many forest industries have adopted the Sustainable Forestry Initiative developed by the American Forest and Paper Association (2000). Standards of the Sustainable Forestry Initiative clearly state the vision and direction for achieving sustainable forest management, goals, and objectives to be attained and performance measures for judging whether a goal or objective has been achieved. However, both public and private entities recognize that current standards, criteria, and indicators represent first approximations. Continuing revision and adjustment based on information from long-term research studies are vital to protecting soil productivity while deriving optimum public benefits from our forest-based resources. [ABSTRACT FROM AUTHOR]

Using survey data and an equilibrium displacement model, we estimate the market and economic impacts of the American Forest and Paper Association's Sustainable Forestry Initiative (SFI) on stumpage markets in the US South. We examine four timber product markets: softwood pulpwood, softwood sawtimber, hardwood pulpwood, and hardwood sawtimber. In each market we calculate changes in producer and consumer welfare using the equilibrium displacement model that accounts for reductions in timber inventories caused by SFI compliance. We find that SFI compliance costs the US South's economy about $36 million annually. SFI-compliant stumpage producers lose more than $33 million each year in producer surplus as a result of SFI compliance, and consumers lose about $12 million annually in consumer surplus due to higher product prices. These costs are offset partially by benefits to nonindustrial private forest producers, non-SFI-compliant industry producers, and public forest producers, who collectively gain about $10 million in producer surplus annually as a result of higher stumpage prices. [ABSTRACT FROM AUTHOR]

The purpose of the paper is to analyse the extent of policy change and learning in the 20 years following the implementation of Ontario's forest sustainability legislation. Extent of policy learning and change towards sustainable forest management are measured using a combination of content, co-occurrence, and textual analysis of the previous Crown Timber Act and the new Crown Forest Sustainability Act, as well as the latter's 1996 and 2009 forest planning manuals. There were four key findings. First, policy change towards sustainable forest management has been limited. Second, although there was an increased number of values mentioned in new legislation and planning manuals, the frequency of timber values remained dominant. Third, although integration occurred among a greater range of values, integration with timber values continued to dominate. Fourth, with respect to policy learning, the achievement of sustainable forest management is now explicit and judged based on evidence regarding the inclusion of a range of values beyond timber. The paper concludes that the transition to the more integrative and responsive policies of sustainable forest management remains a work in progress. [ABSTRACT FROM AUTHOR]

In this paper, we inquire into whether, and by how much, the use in tactical planning of a dense set versus a sparse set of candidate roads can reduce the two major costs (construction and transportation) of forest operations. This inquiry is conducted by using an optimal road location model to generate dense and sparse sets of candidate roads for three different problem instances. These problem instances were then solved using a mixed integer representation of the integrated tactical planning problem. The results show that the use of a dense set versus a sparse set of candidate roads, for all three problem instances, yielded solutions with a mean decrease in transportation and construction costs of 34.34% and 6.94%, respectively. The mean increase in revenue was 1.06%, and the mean increase in the objective function value (revenue minus the total road construction and transportation costs) was 5.62%. In addition, the mapped solutions reveal the spatial attributes of a lower versus a higher cost road network: straighter roads and more efficiently located forks within the road network. These results were obtained to illustrate how reductions in the costs of transportation and road construction can be achieved in tactical planning. [ABSTRACT FROM AUTHOR]

Studying intra-annual growth dynamics through a modelling approach has proved useful for characterizing differences in wood phenology between species and deviations from the expected tree growth due to climate change. The aim of this paper was to determine the climatic factors and the inter- and intra-specific competition traits that drive intra-annual secondary growth dynamics in three Mediterranean tree species that naturally co-exist in the Spanish Northern Plateau ( Pinus pinea L., Juniperus thurifera L., and Quercus ilex subsp. ballota (Desf.) Samp.). For this purpose, we obtained girth increment data from band dendrometers installed on 58 trees from May 2012 to April 2015. Half of them were located in a high-density plot and half were in a low-density plot. These data were analysed through a nonlinear multifactorial model considering daily and cumulative climatic effects together with inter- and intra-specific competition indices. Our results provide evidence of a spatiotemporal niche separation between species. Compared with other species, Q. ilex subsp. ballota showed a wider thermal amplitude, a higher mean optimum temperature for growth, and a milder effect of drought on its secondary growth. Under current climate change projections, simulations based on our model predict a secondary growth reduction for P. pinea and a growth enhancement for Q. ilex subsp. ballota in these Mediterranean mixtures. [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]

The Canadian forest industry is facing several challenges including high fibre cost, decline in commodity profitability, and low investment levels at relatively old manufacturing plants. To enable transformation of the industry, innovations are needed to develop value-added products and to shift to an efficient integrated value chain. In this regard, improved logistics for better handling of raw material, forest biomass utilization, and use of new technologies are some promising avenues. In this paper, we propose a generic value chain model that includes locating new sorting yards and biorefineries maximizing the overall profit of the value chain. This integrated planning problem deals with strategic decisions including investments in new facilities and technologies and tactical decisions comprising backhaul transportation and fibre flows across the value chain. To solve such a problem, we developed a mixed integer programming model to design the forest value chain network. This model is used in an industrial case study in the province of Newfoundland, Canada. We have generated and analyzed 32 scenarios evaluated on 12 predefined key performance indicators. The results show that collaboration through backhauling, common terminals, and new assortments are important opportunities to improve the profitability and efficiency of the value chain. The potential improvement over the current situation is as high as 23% considering the aforementioned actions. [ABSTRACT FROM AUTHOR]

The Russian Federation is one of many countries that have signed the Montreal Protocol and Pan-European Forest Process. These initiatives are aimed at harmonizing national forest inventory systems with criteria and indicators for sustainable forest management. In Russia, the classification of forest type is at the heart of national forest inventory systems. For various historical reasons, Russian scientific advancements in the field of forest typology remain little known in the rest of the world. This paper is aimed at addressing this deficiency. Here, we provide an overview of the main trends in the field of forest typology studies in the previous political states of the Russian Empire, the Soviet Union, and the Russian Federation from the end of the nineteenth century to the beginning of the twenty-first century. We detail the principles that formed the basis of the most significant forest type classifications. We also perform similarity and differences analyses comparing approaches used by members of different scientific schools in the field of forest typology. The historical relationship between ecological, phytocoenotic, genetic, and dynamic forest type classifications are discussed as well as the reasons for the prevalence of certain forest type classifications in different regions of Russia. [ABSTRACT FROM AUTHOR]

The boreal zone and its ecosystems provide numerous provisioning, regulating, cultural, and supporting services. Because of its resources and its hydroelectric potential, Canada's boreal zone is important to the country's resource-based economy. The region presently occupied by Canada's boreal zone has experienced dramatic changes during the past 3 million years as the climate cooled and repeated glaciations affected both the biota and the landscape. For about the past 7000 years, climate, fire, insects, diseases, and their interactions have been the most important natural drivers of boreal ecosystem dynamics, including rejuvenation, biogeochemical cycling, maintenance of productivity, and landscape variability. Layered upon natural drivers are changes increasingly caused by people and development and those related to human-caused climate change. Effects of these agents vary spatially and temporally, and, as global population increases, the demands and impacts on ecosystems will likely increase. Understanding how humans directly affect terrestrial and aquatic ecosystems in Canada's boreal zone and how these effects and actions interact with natural disturbance agents is a prerequisite for informed and adaptive decisions about management of natural resources, while maintaining the economy and environment upon which humans depend. This paper reports on the genesis and present condition of the boreal zone and its ecosystems and sets the context for a detailed scientific investigation in subsequent papers published in this journal on several key aspects: carbon in boreal forests; climate change consequences, adaptation, and mitigation; nutrient and elemental cycling; protected areas; status, impacts, and risks of non-native species; factors affecting sustainable timber harvest levels; terrestrial and aquatic biodiversity; and water and wetland resources. [ABSTRACT FROM AUTHOR]

Some ideas of neuro-dynamic programming (NDP) are illustrated by considering the problem of optimally managing a forest stand under uncertainty. Because reasonable growth models require state information such as height (or age), basal area, and stand diameter, as well as an indicator variable for treatments that have been performed on the stand, they can easily lead to very large state spaces that include continuous variables. Realistic stand management policies include silvicultural options such as pre-commercial and commercial thinning as well as post-harvest treatments. We are interested in problems that are stochastic in their basic growth dynamics, in market prices, and in disturbances, ranging from insects to fire to hurricanes. NDP algorithms are appropriate for problems with large dimensions that may lack a simple model of dynamics and stochastic processes. This paper looks at applying these ideas in the context of a multispecies model. Results show that policies obtained using NDP are optimal within a 95% confidence interval or better. The set of states and controls incorporated into our NDP model allows us to develop optimal policies with a level of detail not typically seen in the forestry literature. [ABSTRACT FROM AUTHOR]

This paper presents a model for optimizing the management of single-species, even-aged stands. The model comprises a number of state variables, given by functions initially differentiable with respect to time, which cease to be due to the discontinuities that cause instant silvicultural treatments. Nevertheless, the proposed model maintains its differentiability with respect to the decision variables (timing, type, and intensity of each thinning, and rotation age). This allows for formulation of the problem of optimal management of this type of stands as a linearly constrained smooth optimization problem, which can be efficiently solved by any derivative-based optimization method. The effectiveness of this formulation is shown by using a sequential quadratic programming (SQP) algorithm to design the optimal management of Pinus pinaster Ait. in Asturias (northwestern Spain) from an economic perspective. These results are compared with those obtained using two methods that do not require derivatives. The SQP, as representative of gradient-type methods, proved robust and much more efficient than the derivative-free methods. [ABSTRACT FROM AUTHOR]

This paper presents a simulation-based analysis of a multiple-round timber combinatorial auction in the timber industry. Currently, most timber auctions are single-unit auctions (i.e., each forest stand is sold separately). However, other types of auctions could be applied to take advantage of the various needs of the bidders with respect to species, volumes, and quality. This study aims to analyze the use of combinatorial auction to this specific context using a simulation approach. Various number of auctions per year, periodicity, lot size, and number of bidders are considered as parameters to set up the different market configurations. The outcomes of both combinatorial auction and single-unit auction are compared with respect to different setup configurations. This analysis shows that combinatorial auction can bring more profit for both seller and buyer when the market is less competitive. [ABSTRACT FROM AUTHOR]

Traditionally, in the initial stage of the forest supply chain, most applications deal with sawlogs to sawmills, pulpwood to pulp mills, or forest residues to heating plants. In this paper, we develop a model that accounts for all raw materials in the forest, i.e., sawlogs, pulpwood, and forest residues, and byproducts from sawmills. They exist in an integrated market where pulpwood can be sent to heating plants as bioenergy. The model represents a multiperiod multicommodity network planning problem with multiple sources of supply, i.e., preselected harvest areas, and multiple types of destinations, i.e., sawmills, pulp mills, and heating plants. Different from the classic wood procurement problem, we take the unit purchasing costs of raw materials as variables on which the corresponding supplies of different assortments depend linearly. The objective of the problem is to minimize the total cost for the integrated market including the purchasing cost of raw materials. Therefore, it is a quadratic programming problem. A large case study in southern Sweden, under different scenario assumptions, is implemented to simulate the integrated market and to study how price restriction, market regulation, harvest flexibility, demand fluctuation, and exogenous change in the price for fossil fuel will influence the entire wood flows. [ABSTRACT FROM AUTHOR]

We respond to the comment by Messier et al. (2011. Can. J. For. Res. 41: 649-653) on our recent paper questioning the possible influence of the base status of soils in the present-day expansion of American beech (Fagus grandifolia Ehrh.) in Quebec (2009. Can. J. For. Res. 39: 2273-2282). From our observations, as well as from a large body of scientific evidence reporting on the high sensitivity of sugar maple (Acer saccharum Marsh.) to the acid-base status of soils, we hypothesized that soil base cation depletion, caused in part by atmospheric deposition, is among the main factors involved in the present-day expansion of American beech over large areas in Quebec. Clearly, we suggested in our paper that acid deposition might act with other factors to explain the expansion of American beech. In this context, our conclusions are far from any oversimplified explanation, as stated by Messier et al., but rather, they point out a level of complexity above the one currently discussed. Nous répondons au commentaire de Messier et al. (2011. Rev. can. rech. for. 41: 649-653) au sujet de notre article publié récemment (2009. Rev. can. rech. for. 39: 2273-2282) traitant de l'influence potentielle de la teneur en cations basiques du sol sur l'expansion actuelle du hêtre à grandes feuilles (Fagus grandifolia Ehrh.) au Québec. Sur la base de nos observations et d'une masse de données scientifiques concernant la grande sensibilité de l'érable à sucre (Acer saccharum Marsh.) à l'équilibre acides-bases dans le sol, nous avons émis l'hypothèse que l'épuisement des cations basiques du sol, causé en partie par les dépôts atmosphériques acides, serait un des principaux facteurs responsables de l'expansion actuelle du hêtre à grandes feuilles sur de vastes superficies au Québec. Nous avons clairement indiqué dans notre article que les dépôts acides pourraient interagir avec d'autres facteurs pour expliquer l'expansion du hêtre à grandes feuilles. Dans ce contexte, nos conclusions sont loin d'être des explications simplistes comme l'affirment Messier et al.; elles font plutôt ressortir un degré de complexité supérieur à celui qui fait présentement l'objet des discussions. [ABSTRACT FROM AUTHOR]

Following centuries of deforestation, Ireland has undergone a substantial afforestation programme in the last 40 years. This paper presents the results of a case study undertaken to examine local response to afforestation. The study is set in Arigna, a region in northwestern Ireland that has traditionally depended on agriculture but has experienced relatively high rates of afforestation in recent decades. Relying on documentary evidence and in-depth qualitative interviews conducted with local stakeholders, the results suggest more local resistance to afforestation than one might expect in a country that has historically experienced such massive deforestation. Among the reasons uncovered for this resistance is the history of land tenure in rural Ireland, the institutional means by which afforestation has been conducted, the tree species used, and the aesthetic appearance of the forest stands once established. Underlying all of this is an apparently widespread local perception that forestry has benefited outsiders more than locals. Yet, the study also documents local perceptions that those responsible for afforestation have responded to concerns and that resistance to afforestation may be declining, as well as the reasons for this decline. The paper concludes with a discussion of the importance of local history and community involvement in developing socially acceptable forestry. [ABSTRACT FROM AUTHOR]

Forest planning models have increased in size and complexity as planners address a growing array of economic, ecological, and societal issues. Hierarchical production models offer a means of better managing these large and complex models. Hierarchical production planning models decompose large models into a set of smaller linked models. For example, in this paper, a Lagrangian relaxation formulation and a modified Dantzig–Wolfe decomposition – column generation routine are used to solve a hierarchical forest planning model that maximizes the net present value of harvest incomes while recognizing specific geographical units that are subject to harvest flow and green-up constraints. This allows the planning model to consider forest-wide constraints such as harvest flow, as well as address separate subproblems for each contiguous management zone for which detailed spatial plans are computed. The approach taken in this paper is different from past approaches in forest hierarchical planning because we start with a single model and derive a hierarchical model that addresses integer subproblems using Dantzig–Wolfe decomposition. The decomposition approach is demonstrated by analyzing a set of randomly generated planning problems constructed from a large forest and land inventory data set. [ABSTRACT FROM AUTHOR]

Vegetation-management practices are applied in temperate-zone forests on the assumption that changing the competitive environment between conifers and unwanted vegetation will improve conifer productivity. We review this assumption using research examining interactions between paper birch (Betula papyrifera Marsh.) and conifers in the highly productive Interior Cedar Hemlock zone of British Columbia. We have found that both competition and facilitation are important in young plantations, where paper birch competes for light, reducing growth of shade-intolerant conifers, but having a facilitative effect on shade-tolerant conifers. This facilitative effect may result from greater ectomycorrhizal diversity, population sizes of Armillaria ostoyae (Romagn.) Herink antagonistic bacteria, and associative nitrogen fixation in plantations where interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) is mixed with paper birch. Where paper birch is manually cut or girdled, conifers grow faster in diameter, but more die as a result of A. ostoyae root disease, and these responses increase with increasing weeding intensity. The weeding treatments do not affect plant community species richness but reduce paper birch dominants and increase understory structural diversity. British Columbia forest policy has been slow to respond to these findings, and we suggest that as a result, the forested landscape incurs substantial risk. We propose additional pathways for managing Interior Cedar Hemlock mixtures to ensure that the natural mix of forest types in the landscape is maintained. [ABSTRACT FROM AUTHOR]

Despite its role as a keystone species, few studies have investigated the habitat requirements of the Yellow-bellied Sapsucker (Sphyrapicus varius (L., 1766)) in the northwestern part of its range, where the current forest harvesting rotation schedule and targets for reducing the prevalence of old and mixedwood stands may reduce the optimal habitat for this species. We studied nesting and foraging habitat requirements of nesting sapsuckers in a boreal mixedwood forest of northwestern Canada by collecting data on nesting sites and foraging substrates on twenty-four 16- to 56-ha plots distributed among four habitat types in 1998 and 2002. Nests (n = 68) were generally found in large (≥22 cm diameter at breast height) trembling aspen (Populus tremuloides Michx) that were alive but declining and that showed high incidence (81.1%) of heartwood rot infection (Phellinus tremulae (Bondarzev) Bondarzev & Borisov in Bondarzev). Nest-site use by sapsuckers was predicted mainly by the presence of external fungal conks and tree diameter. Among tree species used as foraging substrates, paper birch (Betula papyrifera Marsh.) (65.6%) and green alder (Alnus viridis (Vill.) Lam. & DC.) (21.3%) were used most frequently. The use of birch was strongly correlated with its availability. Mature forests had higher densities of nesting sites and foraging substrates than immature aspen stands. In addition to reconfirming the importance of mature mixedwood forests for Yellow-bellied Sapsuckers, our study also indicates that forest harvest rotations in northwestern Canada should exceed 90 years to promote the keystone role of this species. [ABSTRACT FROM AUTHOR]

A previous study by Schmid and Kazda (I. Schmid and M. Kazda. 2001. Can. J. For. Res. 31: 539–548) evaluated the vertical distribution and radial growth of coarse roots greater than 2 mm diameter in pure and mixed stands of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.). The vertical distribution of roots of Norway spruce was fitted by an exponential function, while the root distribution of European beech was approximated by a gamma distribution. Now, in the present paper, planar point process models have been applied to investigate the spatial (two-dimensional) distribution of data for roots between 2 and 5 mm diameter. After a homogenization with respect to the vertical axis, the pair correlation function and the L function were estimated to fit Matérn-cluster point process models to the given root data. The models were finally vertically retransformed to provide information on the inhomogeneous spatial patterns of small roots as well as on the original shape and size of the root clusters. All models based on vertically transformed data confirmed that the root distribution patterns are not completely random, as they indicated root clustering for both species, with different degrees of exploitation intensity (clustering) between the two species. According to the Matérn-cluster models, Norway spruce had stronger clustering in smaller cluster regions, while roots of European beech formed weaker clusters in larger cluster regions. Furthermore, beech root clusters seemed to avoid overlapping. Together with previous studies on the root system of both species, the present study indicates more intensive belowground intraspecific competition for spruce than for beech. On the other hand, the clustering characteristics described indicate that European beech has a more sophisticated rooting system than Norway spruce. The spatial distribution of the inhomogeneous raw data is characterized by the clustering properties analysed in the present paper and by the vertical distribution previously studied. [ABSTRACT FROM AUTHOR]

There is an increasing demand for active public involvement in forestry decision making, but there are as yet few established models for achieving this in the new sustainable forest management (SFM) context. At the level of the working forest, the fields of forest sustainability assessment, public participation, decision support, and computer technology in spatial modelling and visualization need to be integrated. This paper presents the results of a literature review of public participation and decision-support methods, with emphasis on case study examples in participatory decision support. These suggest that emerging methods, such as public multicriteria analysis of alternative forest management scenarios and allied tools, may lend themselves to public processes addressing sustainability criteria and indicators. The paper develops a conceptual framework for participatory decision support to address the special needs of SFM in tactical planning at the landscape level. This framework consists of principles, process criteria, and preliminary guidelines for designing and evaluating SFM planning processes with community input. More well-documented studies are needed to develop comprehensive, engaging, open, and accountable processes that support informed decision making in forest management, and to strengthen guidance for managers. [ABSTRACT FROM AUTHOR]

Understanding tree susceptibility to wind damage is central to natural disturbance and succession studies. Susceptibility depends on the wind loads experienced by trees and their ability to resist these loads. In this study, we investigated the wind force or "drag" acting on the crowns of juvenile specimens of three hardwood species common to northwestern North America, black cottonwood (Populus trichocarpa Torr. & A. Gray), red alder (Alnus rubra Bong.), and paper birch (Betula papyrifera Marsh.). Ten freshly cut crowns of each species were exposed to wind speeds from 4 to 20 m/s in a wind tunnel. At 20 m/s, streamlining reduced the frontal area to 28% of its initial value for black cottonwood, 37% for red alder, and 20% for paper birch. Crown drag coefficients calculated using frontal area in still air varied with wind speed. At 20 m/s they ranged from 0.15 to 0.22 for these species. Drag was proportional to the product of mass and wind speed, and to the product of wind speed squared and wind-speed-specific frontal area. Removing branches by whole-branch pruning had little effect on drag per unit branch mass. To further investigate the effect of leaf size, we also used smaller samples of bigleaf maple (Acer macrophyllum Pursh) and trembling aspen (Populus tremuloides Michx.). Whole-crown drag coefficients did not vary systematically with leaf size, but drag per unit of crown mass increased with leaf size. Bigleaf maple had a higher drag per unit of crown mass than other species. [ABSTRACT FROM AUTHOR]

The SB distributional model of Johnson's 1949 paper was introduced by a transformation to normality, that is, z ~ N(0, 1), consisting of a linear scaling to the range (0, 1), a logit transformation, and an affine transformation, z = γ + δu. The model, in its original parameterization, has often been used in forest diameter distribution modelling. In this paper, we define the SB distribution in terms of the inverse transformation from normality, including an initial linear scaling transformation, u = γ′ + δ′z (δ′ = 1/δ and γ′ = –γ/δ). The SB model in terms of the new parameterization is derived, and maximum likelihood estimation schema are presented for both model parameterizations. The statistical properties of the two alternative parameterizations are compared empirically on 20 data sets of diameter distributions of Changbai larch (Larix olgensis Henry). The new parameterization is shown to be statistically better than Johnson's original parameterization for the data sets considered here. [ABSTRACT FROM AUTHOR]

Variation in canopy composition can influence ecosystem processes, such as nutrient cycling and light transmittance, even when environmental soil conditions are similar. To determine whether forest cover type influences species composition of the understory vegetation (herbs and shrubs), the composition of this layer was studied on two different surface deposits, clay and till, and under four different forest cover types dominated, respectively, by Populus tremuloïdes Michx. (aspen), Betula papyrifera Marsh. (white birch), Pinus banksiana Lamb. (jack pine), and Picea glauca (Moench) Voss – Abies balsamea (L.) Mill. (spruce–fir) over similar environmental conditions. Detrended correspondence analysis and analysis of variance performed on the ordination scores revealed that understory plant composition was highly affected by surface deposit and forest cover. The gradient observed in the correspondence analysis proceeds from aspen, white birch, spruce–fir, to jack pine. Indicator species were identified for each surface deposit and cover type, and most of them were associated with either jack pine or aspen. The richness, evenness, and diversity of the understory vegetation did not vary between cover types, but were affected by surface deposit. By controlling ecosystem processes such as light transmittance and nutrient cycling, forest cover influences understory composition.Key words: cover, understory, composition, boreal forest, environmental condition.La composition du peuplement peut affecter les processus écosystémiques, tels que le cycle des éléments nutritifs et la transmission lumineuse, malgré la présence de conditions environnementales similaires. Afin de vérifier si le couvert arborescent influence la composition de la strate de sous-bois, des relevés de la végétation herbacée et arbustive ont été effectués dans des conditions environnementales détendancées similaires, incluant deux dépôts de surface différents, till et argile, et quatre couverts forestiers dominés respectivement par les Populus tremuloïdes Michx. (peuplier faux-tremble), Betula papyrifera Marsh. (bouleau blanc), Pinus banksiana Lamb. (pin gris) et Picea glauca (Moench) Voss et Abies balsamea (L.) Mill. (épinette–sapin). L'analyse des correspondances détendancées et l'analyse de variance effectuées sur les coordonnées des axes de l'ordination révèlent un effet du dépôt de surface et du couvert arborescent. Le gradient observé en analyse des correspondances va du peuplier faux-tremble, bouleau blanc, mélange de conifères, au pin gris. Des espèces indicatrices ont été identifiées pour chacun des dépôts de surface et couverts forestiers, et la majorité d'entre-elles étaient associées soit au pin gris soit au peuplier faux-tremble. La richesse, l'équitabilité et la diversité de la strate de sous-bois ne varient pas en fonction du couvert forestier, mais sont significativement affectées par le dépôt de surface. Les différents processus écosystémiques, tels que la transmission de la lumière et le cycle des éléments nutritifs, semblent expliquer l'influence du couvert forestier sur la composition de la strate de sous-bois.Mots clés : couvert, sous-bois, composition, forêt boréale, condition environnementale. [ABSTRACT FROM AUTHOR]

Maritime pine ( Pinus pinaster Aiton) forests in the Aquitaine region, southwestern France, suffered catastrophic damage from storms Martin (1999) and Klaus (2009), and more damage is expected in the future due to forest structural change and climate change. Thus, developing risk assessment methods is one of the keys to finding forest management strategies to reduce future damage. In this paper, we evaluated two approaches to calculate wind damage risk to individual trees using data from different damage data sets from two storm events. Airflow models were coupled either with a mechanistic model (GALES) or a bias-reduced logistic regression model to discriminate between damaged and undamaged trees. The mechanistic approach was found to successfully discriminate the trees for different storms but only in locations with soil conditions similar to where the model parameters were obtained from previous field experiments. The statistical approach successfully discriminated the trees only when applied to similar data as that used for creating the models, but it did not work at an acceptable level for other data sets. One variable, decade of stand establishment, was a significant variable in all statistical models, suggesting that site preparation and tree establishment could be a key factor related to wind damage in this region. [ABSTRACT FROM AUTHOR]