La coupe de jardinage est utilisée en forêt tempérée nordique dans les peuplements dont la dynamique de régénération est assurée par les trouées. En créant des ouvertures dans le couvert forestier, elle modifie également le couvert arbustif, qui est un critère important dans la sélection de l’habitat hivernal du lièvre d’Amérique (Lepus americanus Erxleben, 1777), une espèce clé des forêts nord-américaines. L’objectif de cette étude était de déterminer les impacts des coupes de jardinage sur l’habitat du lièvre et d’évaluer le rétablissement de la qualité de l’habitat dans le temps. Pour ce faire, des indices de présence du lièvre (crottins et pistes) ont été modélisés selon des paramètres de qualité d’habitat pour 22 peuplements feuillus traités par une coupe de jardinage entre 1993 et 2007, ainsi que 30 sites non traités (15 témoins feuillus et 15 témoins mixtes), en Abitibi-Témiscamingue, Québec. La sélection de modèles basée sur le critère d’information d’Akaike de second ordre (AICc) a permis d’identifier le couvert latéral comme le seul paramètre de structure d’habitat ayant un effet positif sur l’abondance du lièvre dans les sites étudiés. Les indices de présence du lièvre étaient les plus élevés dans les témoins mixtes, mais étaient plus élevés dans les sites jardinés que dans les témoins feuillus. Nous avons également noté que l’utilisation des sites jardinés augmentait avec le temps écoulé depuis la coupe. Nous concluons que la coupe de jardinage a un effet positif sur la fréquentation des peuplements feuillus par le lièvre d’Amérique.

Gendered knowledge, roles and responsibilities in Indigenous cultures have historically been based on reciprocity and complementarity. By excluding Indigenous women from decision-making, colonial policies have reduced the knowledge base on which decisions are made. Indigenous women’s voices have also been largely excluded from research, and researchers have played a substantial role in their marginalization. It is within this context, and in a research decolonization effort, that we present a case study of the process of co-constructing a data collection tool with Atikamekw women. While preparing a research project on Indigenous women’s roles in the governance of land and natural resources, we worked with three Atikamekw women who gave particularly high importance to the process of obtaining participant consent. We designed the consent form together, so that it would address their concerns about trust, transparency, and community involvement throughout the research process. If research is to be decolonized, research tools should not be developed within university offices, but through meaningful collaboration with research participants.

In 2004, Dr. Marlene Brant-Castellano published a well-received, and now widely cited article entitled "Ethics of Aboriginal research" in the inaugural issue of the Journal of Aboriginal Health. About a decade after this inspirational publication, we asked her to reflect on (1) the progress made in terms of ethics of research with aboriginal people; (2) her views on concrete ways to decolonize research; and (3) challenges yet to overcome in terms of ethical conduct of research with aboriginal people

Marginal stands of balsam fir (Abies balsamea [L.] Mill.) and eastern white cedar (Thuja occidentalis L.) are found north of their limits of continuous distribution in eastern North America. Regional-scale paleoecological studies have suggested that fir and cedar populations could have had larger extents in the past. This study aimed at verifying this hypothesis at the local scale. Wood charcoal fragments were collected from the soils of two marginal fir and cedar stands as well as from 15 sites in the surrounding forest matrix where the species are absent currently. Anatomical identification and radiocarbon-dating showed that fir was more extensive in the study area until about 680 cal. BP, representing up to 31% of the charcoal assemblages at sites where it is currently absent. The evidence is less conclusive for cedar, however, although some of the charcoal fragments from the matrix sites could have been either fir or cedar (undistinguishable). Most of the dated fir/cedar charcoal in the matrix were from the ‘Medieval Warm Period’ (ca. 1000 cal. BP), suggesting contraction may have occurred at that time. Marginal fir – and possibly cedar – stands are thus relics of once more extensive populations. Fire is likely the main factor having contributed to the contraction of the species’ distributions. Fir and cedar are now relegated to areas where fires are less frequent and severe, such as the shores of lakes and rivers.

We present a comparative analysis of fire reconstructions from tree rings and from wood charcoal preserved in forest soils, peat and lake sediments. Our objective is to highlight the benefits and limits of different archives and proxies to reconstruct fire histories. We propose guidelines to optimize proxy and archive choice in terms of spatial and temporal scales of interest. Comparisons were performed for two sites in the boreal forest of northeastern North America. Compared to others archives, tree-ring analysis remains the best choice to reconstruct recent fires (<1000 years). For longer periods (from several centuries to millennia), lake charcoal can be used to reconstruct regional or local fire histories depending on the method used, but the focus should be on historical trends rather than on the identification of individual fire events. Charcoal preserved in peat and soils can be used to identify individual fire, but sometimes cover shorter time periods than lake archives.

Purpose

Aboriginal people in Canada are disproportionately affected by chronic illnesses, compared to non-Aboriginal Canadians. The purpose of this review was to determine whether differences exist between the two groups with respect to chronic non-cancer pain (CNCP) in order to better inform clinical practice and to identify research gaps.

Data sources

Four electronic databases were searched for the period of 1990–2015.

Study selection

Only English and French language original studies that examined CNCP prevalence, assessment tools and beliefs among Aboriginal people in Canada were considered.

Data extraction

Data extracted included Aboriginal group, geographic location, study setting and pain definition (for prevalence studies only).

Results of data synthesis

A total of 11 studies matched the selection criteria: 10 reported estimates of chronic pain prevalence among Aboriginal people in Canada, 1 was about a culturally adapted pain assessment tool, and no study was found about CNCP beliefs within Aboriginal people.

Conclusion

CNCP among Aboriginal people is still a largely unexplored research field. The limited evidence available so far does not allow us to conclude that CNCP affects a higher proportion of Aboriginal than non-Aboriginal people in Canada. However, arthritis, a specific condition associated with chronic pain, is more prevalent in Aboriginal than non-Aboriginal people. Additional research is needed on other CNCP types and conditions. Furthermore, pain assessment tools are not culturally adapted and clinicians should inquire more about the beliefs of Aboriginal patients to make them feel safer and to better target interventions.

Local people and scientists both hold ecological knowledge, respectively stemming from prolonged day-to-day contact with the environment and from systematic inquiry based on the scientific method. As the complementarity between scientific ecological knowledge (SEK) and local ecological knowledge (LEK) is increasingly acknowledged, LEK is starting to be involved in all branches of ecology, including ecological modeling. However, the integration of both knowledge types into ecological models raises methodological challenges, among which (1) consistency between the degree of LEK involvement and modeling objectives, (2) combination of concepts and methods from natural and social sciences, (3) reliability of the data collection process, and (4) model accuracy. We analyzed how 23 published studies dealt with those issues. We observed LEK reaches its full potential when involved at all steps of the research process. The validity of a modeling exercise is enhanced by an interdisciplinary approach and is jeopardized when LEK elicitation lacks rigor. Bayesian networks and fuzzy rule-based models are well suited to include LEK.

The impacts of climate change in remote communities of the Himalaya have been relatively underexplored. This study combines traditional knowledge of people from three Village Development Committees (VDCs) of three districts of the high altitudinal regions in Nepal with scientific data to document the changes in climatic patterns, natural hazards, ecological systems and agricultural practices. The respondents perceived notable changes in the local climatic conditions, the frequency of natural disasters and ecological processes. Their perception of warming over the past 15–20 years parallels the increase in mean annual temperature recorded in the Thehe VDC of the Humla district, Tukuche VDC of the Mustang district and Lelep VDC of the Taplejung district from 1973 to 2012 by 0.02°C/year, 0.04°C/year and 0.01°C/year, respectively. Most respondents perceived an increase in the frequency of floods and landslides. The recorded average frequency of natural hazards including fire, flooding, landslide and avalanche has increased significantly from 1.5?±?0.61 incidences/year for the period 1972–1991 to 10.4?±?2.91 incidences/year for the period 1992–2011. Increased occurrence of pests and insects was also noted. The results show that climate change has already affected local communities and they are responding by spontaneously developing adaptive livelihood strategies.

Introduction Indigenous elders have traditionally played an important role in maintaining social cohesion within their communities. Today, part of this role has been taken over by government social and healthcare services, but they are having limited success in addressing social challenges. Increasing elders’ social participation and intergenerational solidarity might foster community development and benefit young people, families, communities and the elders themselves. However, knowledge of the contribution of elders’ social participation and intergenerational solidarity to wellness is scattered and needs to be synthesised. This protocol presents a scoping review on the social participation of indigenous elders, intergenerational solidarity and their influence on individual and community wellness.

Methods and analysis This scoping review protocol is based on an innovative methodological framework designed to gather information from the scientific and grey literature and from indigenous sources. It was developed by an interdisciplinary team including indigenous scholars/researchers, knowledge users and key informants. In addition to searching information databases in fields such as public health and indigenous studies, an advisory committee will ensure that information is gathered from grey literature and indigenous sources.

Ethics The protocol was approved by the Ethics Review Board of the Université du Québec en Abitibi-Témiscamingue and the First Nations of Quebec and Labrador Health and Social Services Commission.

Discussion The comprehensive synthesis of the scientific and grey literature and indigenous sources proposed in this protocol will not only raise awareness within indigenous communities and among healthcare professionals and community organisations, but will also enable decision-makers to better meet the needs of indigenous people.

Conclusion The innovative methodological framework proposed in this scoping review protocol will yield richer information on the contribution of elders to community wellness. This work is an essential preliminary step towards developing research involving indigenous communities, drawing on the social participation of elders and intergenerational solidarity.

Background
Monitoring of fur-bearing species populations is relatively rare due to their low densities. In addition to catch data, trappers' experience provides information on the ecology and status of the harvested species. Fisher (Pekania pennanti) and American marten (Martes americana) are mustelids that are sensitive to forest management and therefore considered to be ecological indicators of forest health. Fisher populations have increased in eastern North America since the early 2000s and this could have resulted in a northeastern extension of the species' range and increased overlap with marten's range. Moreover, habitats of both species are subject to natural and anthropogenic disturbances. The objective of this study was to document the knowledge held by local trappers in the northern area of sympatry between fisher and marten to identify factors that could explain variation in populations of the two species and interactions between them.

Method
Forty-one semi-directed interviews with Indigenous and non-Indigenous trappers in the Abitibi-Témiscamingue region of western Quebec (Canada), at the northern limit of the overlapping ranges of the two mustelid species.

Results
Trappers highlighted the lack of exclusivity of marten and fisher to coniferous forests, although marten is more closely associated with them than is fisher. Fisher apparently also takes advantage of open environments, including agroforestry systems. Moreover, climate change increases the frequency of freeze-thaw events that cause the formation of an ice crust on the snow surface, which favors fisher movements.

Conclusion
The fisher was identified as a competitor and even a predator of the marten. Furthermore, the fisher is less affected than the marten by forest management, and it also seems to benefit from climate change to a greater extent.

Eastern white pine (Pinus strobus L.) is a cultural keystone tree species in the forests of eastern North America, providing numerous ecosystem services to Indigenous people. White pine abundance in the landscape has considerably decreased over the last few centuries due to overharvesting, suppression of surface fires, extensive management, and plantation failure. The Kitcisakik Algonquin community of western Quebec is calling for restoration and sustainable management of white pine on its ancestral territory, to ensure provision of associated ecosystem services. We present five white pine restoration and management scenarios taking into account community needs and ecological types: (1) natural regeneration of scattered white pines to produce individuals of different sizes and ages used as medicinal plants; (2) protection of supercanopy white pines used as landmarks and for providing habitat for flagship wildlife species, and younger individuals left as regeneration and future canopy trees; (3) the uniform shelterwood system to create white pine-dominated stands that provide habitat for flagship wildlife species and support cultural activities; (4) under-canopy plantations to yield mature white pine stands for timber production; (5) mixed plantations to produce forests with aesthetic qualities that provide wildlife habitat and protect biodiversity.

Questions

We investigated whether the gap disturbance rate (percentage area disturbed by canopy gaps per year) differed at the northern range limit of sugar maple (Acer saccharum)–yellow birch (Betula alleghaniensis) forests compared to broad-leaf temperate deciduous forests located more to the south. As an ancillary question, we assessed the relationship between species composition and gap disturbance rate at the stand scale.

Location

Late successional sugar maple–yellow birch forests at their northern range limit in western Quebec, Canada.

Methods

To reconstruct past gap disturbances, we identified growth releases using the boundary line method applied to tree-ring chronologies obtained from 0.25-ha plots sampled within 11 late successional forest stands. We reconstructed past canopy gaps using release events, calculated historical gap disturbance rates and used redundancy analysis to evaluate the relationship between gap disturbance rate and species composition at the stand scale.

Results

The mean gap disturbance rate across the 11 late successional stands was 0.96 ± 0.51%·yr−1. Mean gap size was 39 ± 44 m2 and almost 85% of the gaps were <50 m2. Stands with smaller gaps and lower gap disturbance rates had high importance values for balsam fir (Abies balsamea) and/or yellow birch.

Conclusions

The gap disturbance rate at the northern limit of sugar maple–yellow birch forest was similar to that reported in broad-leaf temperate deciduous forests located ca. 575–1300 km to the south. However, gaps were more numerous and smaller, which could be related to latitudinal differences in allometric traits of the dominant tree species and climate.

Traditional ecological knowledge (TEK) garners increasing attention in science-based wildlife management. We used the TEK of 16 First Nation hunters from the Eagle Village Algonquin community (Quebec, Canada) to evaluate moose (Alces americanus) habitat suitability in temperate deciduous forests, compared with a habitat suitability index (HSI) model. We found moderate to strong agreement between TEK and the HSI using Cohen’s kappa (? = 0.46–0.63). According to the Algonquin hunters, wetlands and lakes are frequented by moose to feed and to avoid temperature stress during warm summer days, something not taken into account by the HSI. Algonquin hunters also mentioned that unproductive areas are actively frequented by moose in the summer and during the rutting period, although they have a low weight in the HSI calculation. Also according to Algonquin hunters, mature coniferous stands and large-size regenerating areas are rarely used by moose. While the moose HSI model was developed in boreal mixed and coniferous forests, we have shown that it could also be used in temperate deciduous forests. It could be improved, however, to better correspond to TEK, notably by including wetlands and lakes, increasing the weight of unproductive stands and reducing weights of mature coniferous and regenerating stands.

Les savoirs écologiques traditionnels (SET) sont de plus en plus utilisés en gestion de la faune. Nous avons utilisé les SET de 16 chasseurs autochtones de la communauté algonquine de Eagle Village (Québec, Canada) pour évaluer la qualité de l’habitat de l’orignal (Alces americanus) en forêt tempérée feuillue, comparativement à un indice de qualité d’habitat (IQH). Nous avons mesuré un accord modéré à fort entre les SET et l’IQH à l’aide du Kappa de Cohen (? = 0,46–0,63). Selon les chasseurs algonquins, l’orignal fréquente les milieux humides et les lacs pour s’alimenter et éviter le stress thermique durant les chaudes journées d’été, ce qui n’est pas pris en compte par l’IQH. Les chasseurs algonquins ont aussi mentionné que les peuplements improductifs sont fréquentés activement par l’orignal durant l’été et en période de rut, mais ont un faible poids dans le calcul de l’IQH. Toujours selon les chasseurs algonquins, les peuplements résineux matures et les grandes superficies en régénération sont peu utilisés par l’orignal. Bien que le modèle d’IQH de l’orignal ait été développé en forêts boréales mixtes et résineuses, nous avons montré qu’il est aussi approprié pour la forêt tempérée feuillue. Il pourrait toutefois être bonifié pour être plus en phase avec les SET, notamment en tenant compte des milieux humides et aquatiques, en augmentant le poids attribué aux milieux improductifs, et en diminuant les poids attribués aux peuplements résineux matures et aux grandes aires en régénération.

In boreal ecosystems, wildfire severity (i.e., the extent of fire-related tree mortality) is affected by environmental conditions and fire intensity. A burned area usually includes tree patches that partially or entirely escaped fire. There are two types of post-fire residual patches: (1) patches that only escaped the last fire; and (2) patches with lower fire susceptibility, also called fire refuges, that escaped several consecutive fires, likely due to particular site characteristics. The main objective of this study was to test if particular environmental conditions and stand characteristics could explain the presence of fire refuges in the mixedwood boreal forest. The FlamMap3 fire behavior model running at the landscape scale was used on the present-day Lake Duparquet forest mosaic and on four other experimental scenarios. FlamMap3 was first calibrated using BehavePlus and realistic rates of fire spread obtained from the Canadian Fire Behavior Prediction system. The results, based on thousands of runs, exclude the effects of firebreaks, topography, fuel type, and microtopography to explain the presence of fire refuges, but rather highlight the important role of moisture conditions in the fuel beds. Moist conditions are likely attributed to former small depressions having been filled with organic matter rather than present-day variations in ground surface topography.

Food insecurity is a growing concern for indigenous communities worldwide. While the risk of heavy metal contamination associated to wild food consumption has been extensively studied in the Arctic, data are scarce for the Boreal zone. This study addressed the concerns over possible heavy metal exposure through consumption of traditional food in four Anishnaabeg communities living in the Eastern North American boreal forest. Liver and meat samples were obtained from 196 snowshoe hares (Lepus americanus) trapped during winter 2012 across the traditional lands of the participating communities and within 56–156 km of a copper smelter. Interviews were conducted with 78 household heads to assess traditional food habits, focusing on snowshoe hare consumption. Concentrations in most meat and liver samples were below the detection limit for As, Co, Cr, Ni and Pb. Very few meat samples had detectable Cd and Hg concentrations, but liver samples had mean dry weight concentrations of 3.79 mg/kg and 0.15 mg/kg respectively. Distance and orientation from the smelter did not explain the variability between samples, but percent deciduous and mixed forest cover had a marginal negative effect on liver Cd, Cu and Zn concentrations. The estimated exposition risk from snowshoe hare consumption was low, although heavy consumers could slightly exceed recommended Hg doses. In accordance with the holistic perspective commonly adopted by indigenous people, the nutritional and sociocultural importance of traditional food must be considered in risk assessment. Traditional food plays a significant role in reducing and preventing serious health issues disproportionately affecting First Nations, such as obesity, diabetes, and cardiovascular diseases.

Objective

Chronic pain is more prevalent in indigenous populations who often prefer traditional remedies over allopathic drugs. Our objective was to investigate the traditional uses of medicinal plants from the Canadian boreal forest for the management of chronic pain syndromes.

Methods

We reviewed the most extensive database on medicinal plants used by aboriginal people of the Canadian boreal forest to investigate the plants used in the management of 3 of the most common chronic pain syndromes: arthritis/rheumatism; back pain; and headache/migraine. We also reviewed the pharmacology and phytochemistry literature to investigate concordance with indigenous knowledge.

Results

A total of 114 medicinal plant species were reported, of which 27 (23.5%) were used to treat more than 1 chronic pain syndrome. Pharmacological or phytochemical evidence to explain plant function as chronic pain remedy was available in the literature for only 38 species (33%), with several species reported to have anti-inflammatory and analgesic properties effective in treating chronic pain syndromes.

Conclusions

Our study showed the potential of boreal plants as alternative and complementary medicines for the treatment of chronic pain syndromes that could be enhanced by further research on efficacy and safety issues.

Mineral exploration has experienced significant growth over the past decade. Characterized by the absence of production revenues, mineral exploration companies rely on investors, who are increasingly concerned about environmental compliance and social acceptability. Although several guidelines have been developed (e.g. e3 Plus, ISO 26000, BNQ 21000), none provides for third-party evaluation and issuing of a certificate of compliance with sustainable development principles. Given the specificities of the mineral exploration industry, a sectorial certification standard would be better suited to frame their activities. This study suggests a set of principles and criteria of sustainable development that could be the basis for developing a sectorial standard for the mineral exploration industry. Available sustainable development guidelines were analyzed in order to obtain a preliminary list of principles and criteria. A Delphi survey involving 44 experts then allowed to obtain a final, consensual list of 8 principles (Environmental quality, Quality of life, Work environment, Local investment, Business ethics, Transparency and reporting, Innovation, Economic efficiency) and 27 criteria.

In order to embrace the sustainable development challenge, the mining industry must balance economic, environmental and social costs and benefits. Collaboration between the industry, governments and local populations requires an understanding of each other’s needs and views. This paper examines the case of the Kettara abandoned mine in Morocco, comparing perceptions of sustainable mining among the local population, governmental representatives, and industrial developers. All stakeholder groups agreed that sustainable mining is a shared responsibility. Converging themes were mostly environmental: (1) a clear and effective legal framework is needed to ensure adequate environmental protection; (2) best environmental management practices should be employed; and (3) the post-mine closure has to be planned before the beginning of a mining project. Differences in viewpoints were mostly related to socioeconomic issues, and included (1) the role (direct or indirect) of mining companies in fostering community sustainability; (2) the magnitude of the social impacts of mine closure; (3) the risks to the security of employees; (4) the measures to be taken to minimize health impacts on local populations; (5) the amount of investment to be requested from mining companies to guarantee the long-term viability of local communities; and (6) the understanding of inter-generational equity.

La principale stratégie d'aménagement en forêt boréale—les coupes agglomérées (CA)—est de plus en plus critiquée par plusieurs parties prenantes, incluant les peuples autochtones. Deux stratégies alternatives ont été proposées: les coupes dispersées (CD) et l'aménagement écosystémique (AE). Nous avons modélisé les effets à long terme et à l’échelle du paysage de CA, CD et AE sur un ensemble d'indicateurs d'aménagement forestier durable liés aux valeurs d'une communauté autochtone: (1) la structure d’âge de la forêt; (2) la configuration spatiale des peuplements forestiers; (3) la densité du réseau routier; et, (4) la perte d'habitat forestier due aux coupes totales. AE a créé une structure d’âge plus proche de celle qui résulterait d'un régime naturel de perturbations, comparativement à CA et CD. Les blocs de coupe étaient répartis plus uniformément sur le territoire avec AE et CD. Le réseau routier était moins étendu et se développait moins vite avec AE, réduisant ainsi le potentiel de conflits entre usagers de la forêt. AE a aussi maintenu plus de couvert forestier (et donc plus d'habitat faunique potentiel) que CA ou CD. Le scenario AE a obtenu de meilleurs scores pour les quatre indicateurs mesurés, en partie parce que les contraintes imposées à l'exercice de modélisation ont résulté en moins de coupes que dans les autres scénarios. La possibilité forestière annuelle devrait par conséquent être un facteur clé à considérer pour assurer une meilleure conformité aux critères autochtones d'aménagement forestier durable.

Background

Cumulative impacts of wildfires and forest harvesting can cause shifts from closed-crown forest to open woodland in boreal ecosystems. To lower the probability of occurrence of such catastrophic regime shifts, forest logging must decrease when fire frequency increases, so that the combined disturbance rate does not exceed the Holocene maximum. Knowing how climate warming will affect fire regimes is thus crucial to sustainably manage the forest. This study aimed to provide a guide to determine sustainable forest harvesting levels, by reconstructing the Holocene fire history at the northern limit of commercial forestry in Quebec using charcoal particles preserved in lake sediments.

Methods

Sediment cores were sampled from four lakes located close to the northern limit of commercial forestry in Quebec. The cores were sliced into consecutive 0.5 cm thick subsamples from which 1 cm3 was extracted to count and measure charcoal particles larger than 150 microns. Age-depth models were obtained for each core based on accelerator mass spectroscopy (AMS) radiocarbon dates. Holocene fire histories were reconstructed by combining charcoal counts and age-depth models to obtain charcoal accumulation rates and, after statistical treatment, long-term trends in fire occurrence (expressed as number of fires per 1000 years).

Results

Fire occurrence varied between the four studied sites, but fires generally occurred more often during warm and dry periods of the Holocene, especially during the Holocene Thermal Maximum (7000–3500 cal. BP), when fire occurrence was twice as high as at present.

Conclusions

The current fire regime in the study area is still within the natural range of variability observed over the Holocene. However, climatic conditions comparable to the Holocene Thermal Maximum could be reached within the next few decades, thus substantially reducing the amount of wood available to the forest industry.

Objective

Chronic pain is more prevalent in indigenous populations who often prefer traditional remedies over allopathic drugs. Our objective was to investigate the traditional uses of medicinal plants from the Canadian boreal forest for the management of chronic pain syndromes.

Methods

We reviewed the most extensive database on medicinal plants used by aboriginal people of the Canadian boreal forest to investigate the plants used in the management of 3 of the most common chronic pain syndromes: arthritis/rheumatism; back pain; and headache/migraine. We also reviewed the pharmacology and phytochemistry literature to investigate concordance with indigenous knowledge.

Results

A total of 114 medicinal plant species were reported, of which 27 (23.5%) were used to treat more than 1 chronic pain syndrome. Pharmacological or phytochemical evidence to explain plant function as chronic pain remedy was available in the literature for only 38 species (33%), with several species reported to have anti-inflammatory and analgesic properties effective in treating chronic pain syndromes.

Conclusions

Our study showed the potential of boreal plants as alternative and complementary medicines for the treatment of chronic pain syndromes that could be enhanced by further research on efficacy and safety issues.

Wildfires in boreal forest ecosystems usually spare tree stands called post-fire residual patches. There are two types of post-fire residual patches: (1) patches that only escaped fire by chance, probably due to local meteorological conditions unsuitable for fire spread at the moment fire reached their surroundings (random post-fire residual patches), and (2) patches with lower fire susceptibility, that escaped several consecutive fires, likely due to particular site characteristics (fire refuges). Special conservation efforts could target fire refuges owing to their old age, long ecological continuity, and potential specific biological diversity. Here we compared the stand characteristics of 13 post-fire residual patches from the eastern Canadian boreal mixedwood forest to develop guidelines and information for forest managers to differentiate fire refuges from random post-fire residual patches. Two main structural characteristics differentiated fire refuges from random post-fire residual patches: mean tree diameter and thickness of the soil organic matter layer. Thick organic matter accumulation in fire refuges is likely linked to a paludification process, which in turn reduces stand productivity, and thus, mean tree diameter.

Ethnopharmacological relevance Gastrointestinal disorders cause morbidity and can lead to mortality, especially in the developing world where sanitation is deficient. A large part of the human population relies on medicinal plants for treating various diseases, including gastrointestinal disorders. The present review summarizes the traditional uses of medicinal plants of Nepal used to treat gastrointestinal disorders, and evaluates their bio-efficacy based on a review of the available phytochemical and pharmacological literature. Material and methods We searched different electronic databases and libraries for the literature on medicinal plants used in Nepal to treat gastrointestinal disorders. For each species, we also searched the literature for information on conservation status, as well as for phytochemical and pharmacological studies in support of the ethnobotanical information. We used principal component analysis to explore the relation among disorders and plant families, plant life forms, plant parts and preparation modes. We also performed permutation tests to determine if botanical families were used more often than expected considering their availability in the Nepali flora. Results We documented a total of 947 species belonging to 158 families and 586 genera used to treat gastrointestinal disorders in Nepal. Diarrhea was the disorder treated by the highest number of species (348), followed by stomachache (340) and dysentery (307). Among the reported species, five were endemic to Nepal, whereas 16 orchid species were protected under \{CITES\} Appendices \{II\} and III. The randomization test showed that species belonging to 14 families were used less often than expected, whereas plants belonging to 25 families were used more often than expected. The \{PCA\} scatter plot showed distinct groups of gastrointestinal disorders treated with similar plant life forms, plant parts, and/or preparation modes. We found 763 phytochemical studies on 324 species and 654 pharmacological studies on 269 species. Conclusion We showed the diversity and importance of medicinal plants used to treat gastrointestinal disorders in the traditional health care system of Nepal. As such disorders are still causing several deaths each year, it is of the utmost importance to conduct phytochemical and pharmacological studies on the most promising species. It is also crucial to increase access to traditional medicine, especially in rural areas. Threatened species need special attention for traditional herbal medicine to be exploited sustainably.

To evaluate the influence of long-distance transport of charcoal particles on the detection of local wildfires from lake sediment sequences, we tracked three consecutive years of charcoal deposition into traps set within seven boreal lakes in northeastern Canada. Peaks in macroscopic charcoal accumulation (>150?µm) were linked to both local (inside the watershed) and regional wildfires. However, regional fires were characterized by higher proportions of small particles (<0.1?mm2) in charcoal assemblages. We conclude that the analysis of particle size distribution is useful to discriminate “true” local fires from regional wildfires.

Relic old-growth forests are unique witnesses of long-term forest dynamics that can be used as reference conditions for ecosystem-based forest management. In temperate deciduous forests, catastrophic stand-replacing disturbances are rare, and stand dynamics are controlled by endogenous tree-by-tree replacement. Processes might be different at the northern distribution limit of temperate deciduous forests, because of differences in climate and disturbance regimes. We studied tree species composition, diameter, age, and spatial structures of 11 old-growth temperate deciduous stands across an age gradient. Stand characteristics differed from expectation, based on previous studies that were conducted in the central region of the range of temperate deciduous forests. Instead of increasing with age, tree species richness was higher in stands <120 years old because of the presence of relatively short-lived species such as Abies balsamea and Acer rubrum. All diameter distributions followed a two- or three-parameter Weibull model, instead of a rotated sigmoid. Some age structures showed recruitment pulses, contrary to the expectation of constant recruitment, and the spatial distribution of living trees was mostly random with regard to age and species at assessed distances (<14 m). In the context of ecosystem-based forest management, our results suggest that harvest levels should vary across harvesting blocks and selection silviculture should occasionally include larger, multiple-tree gaps in addition to single-tree gaps.

Les feux de forêt constituent une importante perturbation en forêt boréale. Le climat, la température, la topographie, la végétation, les dépôts de surface et les activités humaines représentent autant de facteurs pouvant les influencer. À l’inverse, les feux de forêt affectent le climat par l’émission de gaz et d’aérosols et modifient l’albédo de surface, les processus édaphiques et la dynamique de la végétation. On ne connaît pas encore très bien l’effet net de ces facteurs, mais ils semblent avoir exercé une rétroaction négative sur le climat au cours du XXe siècle. Cependant, on prédit une augmentation des feux de forêt vers la fin du XXIe siècle susceptible de modifier leurs effets sur le climat vers une rétroaction positive capable d’exacerber réchauffement planétaire. Cette synthèse présente (1) une revue d’ensemble des régimes des feux et de la succession de la végétation en forêts boréales, (2) les effets sur le climat des émissions de combustion et des changements du fonctionnement des écosystèmes après feu, (3) les effets des variations du régime de feu sur le climat, particulièrement sur les changements de stock de carbone et d’albédo de surface, (4) une approche intégrée des effets des feux sur la dynamique du climat et (5) l’implication de l’augmentation de l’activité des feux sur le réchauffement planétaire en calculant le forçage radiatif de plusieurs facteurs vers 2100 en région boréale, avant de discuter les résultats et d’exposer les limites des données. Généralement, les pertes en carbone occasionnées par les feux de forêt en région boréale augmenteront dans le futur et leur effet sur les stocks de carbone (0,37 W/m2/décennie) sera plus grand que l’effet du feu sur l’albédo de surface (−0,09 W/m2/décennie). L’effet net des émissions d’aérosols venant des feux en forêt boréale causera vraisemblablement une rétroaction positive sur le réchauffement planétaire. Cette synthèse met l’accent sur l’importance des rétroactions entre les feux et le climat en forêt boréale. Elle présente les limites et les incertitudes à aborder dans les prochaines études, surtout en relation avec les effets de la fertilisation par le CO2 sur la productivité forestière, laquelle pourrait contrebalancer ou atténuer les effets du feu.

Wildfires in boreal forest ecosystems usually spare tree stands called post-fire residual patches. There are two types of post-fire residual patches: (1) patches that only escaped fire by chance, probably due to local meteorological conditions unsuitable for fire spread at the moment fire reached their surroundings (random post-fire residual patches), and (2) patches with lower fire susceptibility, that escaped several consecutive fires, likely due to particular site characteristics (fire refuges). Special conservation efforts could target fire refuges owing to their old age, long ecological continuity, and potential specific biological diversity. Here we compared the stand characteristics of 13 post-fire residual patches from the eastern Canadian boreal mixedwood forest to develop guidelines and information for forest managers to differentiate fire refuges from random post-fire residual patches. Two main structural characteristics differentiated fire refuges from random post-fire residual patches: mean tree diameter and thickness of the soil organic matter layer. Thick organic matter accumulation in fire refuges is likely linked to a paludification process, which in turn reduces stand productivity, and thus, mean tree diameter.

Fire frequency is expected to increase in boreal forests over the next century owing to climate change. In Quebec (Canada), the location of the northern limit of commercial forests (c. 51 °N) was established in 2000 taking into account mainly forest productivity and fire risk. The location of the limit is currently under debate and is being re-evaluated based on a more extensive survey of the territory. We characterized the natural variability of fire occurrence (FO) in the area surrounding the northern limit, and these results are a useful contribution to discussions on the re-evaluation of its location. Regional FO over the last 7000 years was reconstructed from sedimentary charcoal records from 11 lakes located in three regions surrounding the northern limit (i.e. south, north and near the limit). Holocene simulated precipitation and temperature from a general circulation model (GCM) were used to identify the long-term interactions between climate and fire. Fire histories displayed similar trends in all three regions, with FO increasing from 7000 calibrated years before present (cal. years BP) to reach a maximum at 4000-3000 cal. years BP, before decreasing during the late-Holocene. This trend matches the simulated changes in climate, characterized by drier and warmer conditions between 7000 and 3500 cal. years BP and cooler and moister conditions between 3500 and 0 cal. years BP. Northern ecosystems displayed higher sensitivity to climate change. The natural variability of FO was narrower in the southern region compared with the limit and northern regions. An abrupt decrease in FO was recorded close to and north of the limit at 3000 cal. years BP, whereas the decrease was more gradual in the south. Synthesis and applications. We reconstructed the natural variability in fire activity over the last 7000 years near the current location of the northern limit of commercial forests in Quebec. Fire occurrences were more sensitive to climate change near to and north of the limit of commercial forestry. In the context of predicted increase in fire activity, the lower resilience of northern forests advocates against a northern repositioning of the limit of commercial forests. © 2014 The Authors.

We compared fire episodes over the past 150 years reconstructed using charcoal particles retrieved from well-dated sediment deposits from two small lakes in the eastern Canadian boreal forest, with dendrochronological reconstructions of fire events from the corresponding watersheds. Fire scars and age structure of living trees highlighted three fire events (AD 1890, 1941, and 1989). To explore the ability to detect these fire events based on sedimentary charcoal records, we explored the influence of two user-determined parameters of a widely used peak-detection algorithm (the CharAnalysis software): (1) the temporal resolution used to interpolate charcoal series and (2) the width of the smoothing window used to model background noise. The signal-to-noise index (SNI) is often used to evaluate the ability to detect peaks in sedimentary charcoal records, which can be related to fire events. SNI values >3 identify records appropriate for peak detection. Selecting standard settings in paleoecological studies (median temporal resolution of the entire sequence and 500- to 1000-year window width) yielded higher global SNI values but failed to detect most recent fire events. Instead, selecting a shorter reference period (the past ~150 years) to determine the temporal resolution to interpolate the charcoal series and a narrower smoothing window (100 years) best matched the tree-ring data despite lower SNI values (often <3.0). However, Holocene fire history differed markedly when reconstructed using different smoothing window widths (100–150 years vs >300 years). Consequently, we suggest using the smallest window width yielding a SNI >3. Practitioners must not necessarily focus on obtaining the highest possible SNI, usually related to wide smoothing windows. We also suggest that fire history reconstructions should focus on core sections presenting fairly constant sedimentation rates. Alternatively, sediments could be subsampled after age–depth models have been obtained.

Afin d’évaluer les facteurs environnementaux expliquant la limite nordique de répartition du bouleau jaune (Betula alleghaniensis Britton) dans l’est du Canada, nous avons analysé l’abondance, la structure d’âge, le taux d’accumulation de biomasse et la sensibilité de la croissance au climat de cette espèce dans 14 sites répartis le long d’un gradient latitudinal de 200 km couvrant trois domaines bioclimatiques et atteignant les populations les plus nordiques dans l’ouest du Québec. Nous avons observé une grande variabilité de la densité de plantules entre les domaines, ainsi que de la présence de sites avec une régénération abondante du bouleau jaune dans chaque domaine bioclimatique. La densité de plantules était corrélée positivement à l’âge moyen et à l’abondance des bouleaux jaunes mâtures dans la canopée, alors que la densité de gaulis était positivement associée aux habitats plus secs. Les patrons de croissance des arbres mâtures n’ont pas montré d’effet négatif de la température le long du gradient sud-nord. Les facteurs contrôlant la limite nordique de répartition du bouleau jaune agissaient sur la régénération, mais pas sur la croissance des arbres mâtures. À l’échelle du peuplement, la densité de régénération était fortement contrôlée par les conditions locales de site, et non par les différences climatiques entre les sites. A l’échelle régionale, la variabilité climatique pourrait indirectement contrôler la répartition du bouleau jaune en affectant la fréquence des perturbations et, conséquemment, la disponibilité de sites propices à la régénération.

Burned areas in boreal mixedwood forests usually include tree patches that partially or entirely escaped fire. Some of these post-fire residual stands – called fire refuges – can escape several consecutive fires due to particular microsite conditions. Despite their potential importance as biodiversity hotspots, the long-term forest dynamics of fire refuges is unknown. High-resolution analysis of plant macroremains retrieved from forest organic matter profiles sampled in five fire refuges allowed us to describe up to 8000 years of forest dynamics. Our results display the importance of local conditions in forest dynamics. Wildfire was probably prevented by high moisture, as indicated by the presence of aquatic taxa and moisture-tolerant tree species. Lack of stand-replacing fire, coupled with organic matter accumulation, favored the millennial persistence of late-successional tree species. Shifts from spruce/larch dominance to fir/cedar dominance were noted at different occasions during the Holocene, probably resulting from endogenous processes.

The abundance of eastern white pine (Pinus strobus L.) has been significantly reduced across its distribution range over the past few centuries. The species’ regeneration dynamics is well documented in the centre of its range, but is poorly understood at the northern limit of continuous distribution. To address this knowledge gap, we quantified natural white pine regeneration in unmanaged mature stands, identified the most important variables influencing it, and evaluated the impact of damaging agents, namely white pine blister rust (Cronartium ribicola J.C. Fisch.), white pine weevil (Pissodes strobi Peck), and herbivory. We also quantified the influence of remnant stands and residual trees on the spatial distribution of regeneration in logged sites. The results reveal continuous but low recruitment in mature stands. The basal area of balsam fir (Abies balsamea (L.) Miller) had a strong negative effect on white pine regeneration. Regeneration was more abundant than expected on moister substrates, including moss, decaying wood and organic matter. White pine regeneration was noted in recently logged areas, where distance from remnant stands had a significant effect on the abundance of white pine regeneration. The northern limit of continuous distribution holds potential for white pine restoration, for example by preserving remnant white pine stands that can provide seed sources for natural regeneration in a shelterwood cut system, or in adjacent clearcut areas. This study illustrates that different management strategies should be used near northern range limits, where effects of site conditions and disturbance agents are different than in the center of a species’ range.

Les effets sur l’approvisionnement en matière ligneuse découlant de l’implantation d’une stratégie d’aménagement écosystémique ont été analysés dans le cas d’une unité de la forêt boréale sous aménagement forestier dans l’est du Canada. Une programmation linéaire standard a été utilisée pour évaluer les effets de quatre principales politiques : (1) chercher à établir une structure d’âge cible de la forêt découlant du cycle naturel des feux de forêts et de la dynamique forestière (approche avec plusieurs cohortes), (2) rapprocher les blocs de coupe dans les zones exploitées afin de reproduire les patrons de perturbation naturelle à l’échelle du paysage, (3) maintenir les niveaux cumulatifs de coupe à blanc et de perturbations naturelles à l’intérieur de l’intervalle habituel de variabilité et (4) exclure les coupes d’exploitation dans les zones d’intérêt potentiel pour les peuples autochtones. La structure d’âge cible de la forêt a été atteinte suite à une réduction minime de l’approvisionnement périodique en matière ligneuse, mais seulement après 50 ans. Comparativement au scénario « usuel », l’inclusion des trois premières politiques a entraîné une réduction de 3% à 11% de l’approvisionnement planifié en matière ligneuse et une période de restauration nécessitant que 43% à 67% du territoire productif soit exclu des activités de coupe pour les 50 prochaines années. De tels résultats impliquent que les coupes partielles ne soient pas confinées dans les zones d’opération retenues pour la coupe à blanc. L’exclusion additionnelle du territoire forestier ayant un intérêt potentiel pour les peuples autochtones a provoqué une réduction supplémentaire de 4% à 10% de l’approvisionnement planifié en matière ligneuse. La validation des trois critères de base utilisés dans cette étude (les trois premières politiques) a été effectuée au moyen des exigences en matière d’habitat du caribou des bois (Rangifer tarandus caribou). Presque tous les scénarios ont engendré un niveau de perturbation permettant vraisemblablement le maintien des populations de caribou des bois en moins de 25 ans.

Les arbres et les forêts ont toujours joué un rôle important dans la culture et la spiritualité des sociétés. La compréhension de l'importance culturelle des espèces arborescentes est nécessaire pour développer des stratégies de restauration et d'aménagement socialement acceptables. Le pin blanc (Pinus strobus L.) était autrefois plus abondant dans les forêts du nord-est de l'Amérique du Nord, notamment sur le territoire ancestral de la communauté algonquine de Kitcisakik (Québec, Canada). La communauté revendique la restauration et l'aménagement durable du pin blanc sur son territoire ancestral. Un premier pas vers cet objetif a été franchi en réalisant des entrevues avec des informateurs clés de la communauté afin de documenter l'importance culturelle de l'espèce. Le pin blanc était perçu comme une composante importante de la vie traditionnelle, fournissant de nombreux biens et services. L'espèce figure dans des légendes, est utilisée comme plante médicinale, procure de l'habitat à des espèces fauniques d'intérêt, et est une constituante importante des paysages culturels. Le pin blanc est une espèce culturelle clé de la communauté algonquine de Kitcisakik. Les gens de la communauté ont identifié la surexploitation des forêts de pin blanc comme raison principale du déclin de l'espèce sur leur territoire ancestral. Ils ont suggéré que des plantations mixtes pourraient être utilisées dans une stratégie de restauration culturellement adaptée.

The effects on timber supply incurred by implementing an ecosystem-based management strategy were evaluated in an eastern Canadian boreal forest management unit. Standard linear programming was used to test the effects of four key policy issues: (1) aim for a targeted forest age structure inspired by natural fire regime and forest dynamics (multi-cohort approach), (2) agglomerate harvest blocks in operating areas to reproduce natural disturbance patterns at the landscape scale, (3) maintain cumulated clearcutting and natural disturbance rates inside the historical range of variability, and (4) exclude from harvest areas of potential interest to aboriginal people. The targeted forest age structure was achieved with a minimum reduction of periodic timber supply, but only after 50 years. Compared to a "business-as-usual" scenario, inclusion of the first three policy issues resulted in a 3% to 11% reduction in planned timber supply and a restoration period requiring that 43% to 67% of the productive area be excluded from clearcutting activities for the next 50 years. Such results require that partial cutting not be confined to operating areas eligible for clearcutting. Further exclusion of forest areas of potential interest to aboriginal people resulted in an additional 4% to 10% decrease in planned timber supply. Validation of the coarse filters used in this study (first three policy issues) was done using habitat requirements of woodland caribou (Rangifer tarandus caribou). Almost all scenarios induced a disturbance rate likely to allow a self-sustaining woodland caribou population within 25 years.

The boreal forest of Canada is home to several hundred thousands Aboriginal people who have been using medicinal plants in traditional health care systems for thousands of years. This knowledge, transmitted by oral tradition from generation to generation, has been eroding in recent decades due to rapid cultural change. Until now, published reviews about traditional uses of medicinal plants in boreal Canada have focused either on particular Aboriginal groups or on restricted regions. Here, we present a review of traditional uses of medicinal plants by the Aboriginal people of the entire Canadian boreal forest in order to provide comprehensive documentation, identify research gaps, and suggest perspectives for future research.

L'intérêt du secteur de la recherche et développement pour les connaissances traditionnelles est considérable. La contribution des savoirs traditionnels à la conservation et à l'aménagement est de plus en plus reconnue et des expériences terrain en ce sens sont en cours dans plusieurs pays. Le niveau de dégradation des écosystèmes justifie le besoin d'interventions de restauration. Il est de plus en plus reconnu que l'intégration des connaissances scientifiques et traditionnelles est nécessaire au succès des efforts de restauration. Cette synthèse évalue les contributions actuelles et potentielles des savoirs traditionnels à la restauration écologique. Malgré qu'un nombre croissant d'articles soient publiés à propos des connaissances traditionnelles, peu concernent la contribution à la restauration écologique. Les principales contributions des connaissances traditionnelles à la restauration écologique sont l'identification d'écosystèmes de référence, en particulier lorsque les informations historiques ne sont pas disponibles; la sélection d'espèces pour les plantations; la sélection de sites pour la restauration; la connaissance de l'historique local des pratiques d'aménagement; la gestion des espèces envahissantes; et le suivi post-restauration. Les connaissances traditionnelles et scientifiques sont complémentaires et devraient être utilisées conjointement dans les projets de restauration écologique. L'inclusion des connaissances traditionnelles peut contribuer à construire un partenariat solide pour le succès de mise en oeuvre de projets de restauration et pour en augmenter l'acceptabilité sociale, la faisabilité économique et la viabilité écologique.

A survey of plant biodiversity and ethnobotany was conducted along the Seti river banks in the Tanahun district of Western Nepal. This area, home of the Magar ethnic group, will be impacted by a major hydropower project, currently under feasibility study. The objective of the study was to document plant biodiversity and ethnobotany in order to suggest appropriate conservation and management strategies. Botanical sampling was conducted inside quadrats and along transects. A total of 221 plant species were recorded in the study area, distributed as herbs (80 species), trees (68), shrubs (28), climbers (19), pteridophytes (18), lianas (5), and epiphytes (3). Twelve of the inventoried species figure in one or more conservation categories identified by various national or international agencies. Group discussions and personal interviews allowed to find out that 43% of the species were ethnobotanically important for the local people and that most were used as medicine, food, or timber. We propose specific species for sustainable use programs based on certain criteria. The area is very important in terms of plant biodiversity and ethnobotany, and hence, immediate implementation of conservation measures is recommended to maintain the high social, ecological and economic values of the area.

Background: By revealing historical and present plant use, ethnobotany contributes to drug discovery and socioeconomic development. Nepal is a natural storehouse of medicinal plants. Although several ethnobotanical studies were conducted in the country, many areas remain unexplored. Furthermore, few studies have compared indigenous plant use with reported phytochemical and pharmacological properties.

Methods: Ethnopharmacological data was collected in the Rasuwa district of Central Nepal by conducting interviews and focus group discussions with local people. The informant consensus factor (FIC) was calculated in order to estimate use variability of medicinal plants. Bio-efficacy was assessed by comparing indigenous plant use with phytochemical and pharmacological properties determined from a review of the available literature. Criteria were used to identify high priority medicinal plant species.

Results: A total of 60 medicinal formulations from 56 plant species were documented. Medicinal plants were used to treat various diseases and disorders, with the highest number of species being used for gastro-intestinal problems, followed by fever and headache. Herbs were the primary source of medicinal plants (57% of the species), followed by trees (23%). The average FIC value for all ailment categories was 0.82, indicating a high level of informant agreement compared to similar studies conducted elsewhere. High FIC values were obtained for ophthalmological problems, tooth ache, kidney problems, and menstrual disorders, indicating that the species traditionally used to treat these ailments are worth searching for bioactive compounds: Astilbe rivularis, Berberis asiatica, Hippophae salicifolia, Juniperus recurva, and Swertia multicaulis. A 90% correspondence was found between local plant use and reported plant chemical composition and pharmacological properties for the 30 species for which information was available. Sixteen medicinal plants were ranked as priority species, 13 of which having also been prioritized in a country-wide governmental classification.

Conclusions: The Tamang people possess rich ethnopharmacological knowledge. This study allowed to identify many high value and high priority medicinal plant species, indicating high potential for economic development through sustainable collection and trade.

Abstract:

The relative importance of fire and flooding on the population dynamics of eastern white-cedar (Thuja occidentalis L.) and black ash (Fraxinus nigra Marsh.) was evaluated in eight old-growth riparian stands of southwestern boreal Quebec, Canada. Rising water levels and decreasing fire frequency since the end of the Little Ice Age (ca. 1850) were expected to have favoured an inland migration of the riparian forest fringe, with the flood-tolerant black ash colonizing the lower parts of the shore terraces and eastern white-cedar the upper parts. Black ash was found to be restricted to the riparian zone (<200 cm elevation), whereas eastern white-cedar trees did not occur below 100 cm above lake level. Gaps of postfire eastern white-cedar recruitment were noted in stands exposed to riparian disturbances, whereas relatively continuous recruitment occurred at protected sites. Black ash, more tolerant to flooding and ice push, invaded the shore terrace sites left vacant by eastern white-cedar. The riparian forest fringe surrounding Lake Duparquet is currently migrating upland and this trend is expected to continue as water levels continue to increase and fire frequency continues to decrease during the 21st century.© 2008 NRC Canada.

Résumé

L’importance relative de deux des principales perturbations de la forêt boréale, le feu et les crues, sur la dynamique des populations de thuya occidental (Thuja occidentalis L.) et de frêne noir (Fraxinus nigra Marsh.) a été évaluée dans huit peuplements riverains du sud-ouest de la forêt boréale du Québec (Canada). L’hypothèse était que l’augmentation des niveaux d’eau et la diminution de la fréquence de feux depuis la fin du Petit Âge Glaciaire (ca. 1850) auraient favorisé une migration vers l’intérieur des terres de la frange forestière riveraine, le frêne noir, tolérant aux inondations, colonisant les parties basses des terrasses et le thuya occidental les parties hautes. Le frêne noir était restreint à la zone riveraine (<200 cm au-dessus du niveau d’eau), tandis qu’aucun thuya occidental mature ne se trouvait sous 100 cm au-dessus du niveau d’eau. Des épisodes de faible recrutement ont été notés dans les peuplements de thuya occidental exposés aux perturbations riveraines, tandis que le recrutement était relativement continu dans les sites protégés. Le frêne noir, plus tolérant aux crues et aux poussées glacielles, a envahi les terrasses riveraines abandonnées par le thuya occidental. La frange forestière riveraine du lac Duparquet est présentement en migration vers l’intérieur des terres et la tendance devrait continuer suivant l’augmentation des niveaux d’eau et la diminution des fréquences de feu au XXIe siècle.© 2008 NRC Canada.

The coniferous boreal forest of northeastern North America is characterized by large and severe fire events and dominated by black spruce (Picea mariana), with scattered patches of balsam fir (Abies balsamea), a species otherwise predominant in the more southern mixedwood boreal forests, characterized by smaller and less severe fire events. Because balsam fir is a late-successional species ill-adapted to fire, this study aimed at determining if the scattered balsam-fir patches found in the coniferous forest were relics of a former fire regime characterized by less frequent and/or severe conflagrations. Fire and vegetation history were assessed for a coniferous forest site through analyses of charcoal, pollen and plant macroremains preserved in lake sediments, peat and hydromorphic forest soil. Pollen and macroremains analyses show that black spruce dominated the local vegetation since deglaciation (c. 8000 cal. yr BP). Balsam fir was abundant around the site during the warm and humid summers of the Hypsithermal (between c. 7000 and 3500 cal. yr BP), before gradually declining during the cool and dry Neoglacial, which was characterized by increased fire frequency and severity. Scattered balsam fir patches in the coniferous forest result from the fragmentation of formerly larger populations and are presently in disequilibrium with climate.© 2008 SAGE publications. All rights reserved.

La réaction des peuplements riverains de cèdre blanc (Thuja occidentalis L.) à la construction de deux barrages sur le lac Abitibi — un grand plan d’eau situé dans la région boréale méridionale de l’est du Canada — a été analysée afin de déterminer si la limite lacustre du cèdre blanc est déterminée par le stress physiologique dû à l’inondation ou par les perturbations riveraines. La hausse d’environ 1,2 m du niveau d’eau, engendrée par la construction du premier barrage en 1915, a causé la mort instantanée de tous les arbres qui formaient l’ancienne lisière de la forêt et provoqué des blessures et l’inclinaison des arbres survivants (formant la marge forestière actuelle), par l’action des vagues ou l’activité glacielle. La construction du deuxième barrage, en 1922, n’a pas augmenté significativement le niveau d’eau, mais a plutôt entraîné un retard et une baisse de magnitude des crues printanières, sans toutefois affecter la croissance des cèdres blancs riverains. La croissance radiale n’a pas été affectée par l’inondation, probablement parce que les crues printanières étaient déjà terminées avant le début de la saison de croissance (1915–1921), ou parce qu’elles étaient de trop courte durée pour nuire au métabolisme des arbres (après 1921). Il s’ensuit que (i) la limite lacustre du cèdre blanc est une limite mécanique liée à l’action des vagues et à l’activité glacielle, plutôt qu’une limite physiologique due à l’inondation, et (ii) que les paramètres de croissance reliés aux perturbations, tels les cicatrices glacielles, la formation de bois de compression et la mortalité partielle du cambium, sont de meilleurs indicateurs que la largeur des cernes de croissance, pour reconstituer l’augmentation à long terme du niveau d’eau de lacs naturels.

The reproductive potentials of balsam fir and white spruce (co-dominants in mixedwood forests) and black spruce (dominant in coniferous forests) were studied to explain the location of the ecotone between the two forest types in the boreal zone of Quebec. Four sites were selected along a latitudinal gradient crossing the ecotone. Cone crop, number of seeds per cone, percentage filled seeds, and percentage germination were measured for each species. Balsam fir and white spruce cone crops were significantly lower in the coniferous than in the mixedwood forest, while black spruce had greater crop constancy and regularity between both forest types. Mast years were more frequent for black spruce than for balsam fir in both forest types (mast year data not available for white spruce). The number of seeds per cone was more related to cone size than to forest type for all species. Black spruce produced more filled seeds in the coniferous forest than balsam fir or white spruce. The sum of growing degree-days and the maximum temperature of the warmest month (both for the year prior to cone production) significantly affected balsam fir cone production. The climate-related northward decrease in reproductive potential of balsam fir and white spruce could partly explain the position of the northern limit of the mixedwood forest. This could change drastically, however, as the ongoing climate warming might cancel this competitive advantage of black spruce.

The basic unit of the forest-tundra landscape is a toposequence extending from a wet, forested valley to a xeric, deforested hilltop; the contact zone between these two environments being called a subarctic tree line. Dendrochronological analysis of living, dead, and subfossil black spruce, and radiocarbon dating of peat samples were used to reconstruct the dynamics of a subarctic tree line since its post-fire origin about 1000 y ago. Fire is not the sole disturbance to have influenced the dynamics of the toposequence. A regional-scale flooding event ca. 1120 AD killed many black spruce trees, growth of permafrost during the Little Ice Age, and its subsequent degradation in the 20th century, also had major consequences. The climate was favourable to black spruce growth between ca. 300 and 1100 AD, as evidenced by large growth rings and tree growth forms. Ring widths then decreased markedly between the 12th and 19th centuries and trees were replaced by stunted growth forms. Although climate warming during the 20th century resulted in increased ring widths, black spruces have still not produced tree growth forms, a necessary condition for viable seed production and eventual re-colonization of deforested hilltops.

Depuis des décennies, plusieurs ont soutenu que les effets de la coupe forestière et des feux de forêts étaient significativement différents et que ceci aurait des effets significatifs sur les processus des écosystèmes et sur la biodiversité. Toutefois, c’est seulement récemment que des quantités appréciables de données scientifiques ont été amassées à ce propos. Dans ce rapport, nous présentons une revue des similarités et des différences entre les effets écologiques des perturbations associées aux incendies et à la coupe forestière qui ont été observées dans la littérature scientifique. Les comparaisons des effets de ces perturbations sur de nombreux attributs forestiers (les débris ligneux grossiers, les éléments nutritifs du sol, la productivité forestière, la diversité des plantes et la réponse de la faune) sont présentées selon deux échelles spatiales distinctes : celle du peuplement et celle du paysage.

À l’échelle du peuplement, notre revue a révélé des différences significatives entre les coupes forestières et les feux de forêts tôt après la perturbation. D’un point de vue de la structure des peuplements, les forêts après incendie sont caractérisées par un plus grand nombre de chicots et moins de débris ligneux au sol, de même qu’un humus forestier significativement plus mince que celui des sites récoltés. De plus, même si les deux perturbations génèrent une augmentation dans la quantité d’éléments nutritifs extractibles dans le sol, l’intensité de cette augmentation est plus grande après feu qu’après coupe. Également, on observe une augmentation du pH du sol après un incendie contrairement à peu de changement ou à une faible baisse après coupe.

Tôt après la perturbation, les éléments de biodiversité diffèrent significativement dans les sites incendiés comparativement aux sites récoltés. Des communautés différentes de plantes vasculaires et non vasculaires du sous-bois colonisent généralement les sites incendiés et récoltés quoique les différences soient habituellement une question d’abondance plutôt que d’absence/présence des espèces. Comparativement au feu, les assemblages fauniques, que ce soit les mammifères, les invertébrés ou les oiseaux, semblent tous répondre différemment à la récolte. Parmi ces groupes fauniques, les espèces spécifiquement associées aux chicots étaient les plus susceptibles de montrer une réponse différente selon la perturbation (coupe ou feu).

Les espèces d’arbres répondent différemment selon la perturbation (feu ou coupe), la récolte favorisant l’établissement d’espèces feuillues (notamment le peuplier faux-tremble, Populus tremuloides) et d’espèces de conifères qui ne sont pas adaptées aux incendies telles que le sapin baumier (Abies balsamea). Par ailleurs, il y a typiquement plus d’arbres feuillus résiduels suite aux coupes à blanc qu’après incendies. Étant donné ce fait et à cause de la réponse différentielle des espèces d’arbres à ces deux types de perturbations, des dynamiques de succession divergentes, pour ce qui est de la composition des arbres, peuvent être observés entre les peuplements incendiés et récoltés. Même si nous avons observé une certaine variabilité entre les études, la productivité forestière est généralement similaire dans les sites incendiés et récoltés.

Lorsqu’on compare les effets des perturbations associées à la récolte et aux feux de forêts à des échelles temporelles plus longues, notre revue indique que la plupart des attributs forestiers, qui étaient différents tôt après la perturbation, convergeaient quelques décennies après perturbation. Néanmoins, les humus forestiers plus épais observés après la récolte, comparativement à ceux observés après un incendie, semblaient persister plusieurs décennies après la perturbation. De plus, même si les communautés fauniques deviennent plus similaires avec le temps, plus tard dans la succession, certaines espèces présentes dans les peuplements incendiés sont soit significativement moins abondantes ou soit absentes dans les peuplements récoltés d’âge similaire. Enfin, plusieurs études soulignent que même si les effets des perturbations associées aux feux et à la récolte ne diffèrent pas significativement après quelques décennies, il y a certains doutes qui subsistent quant à la capacité des coupes forestières à recréer le large éventail de variabilité naturelle observée à la suite d’un incendie.

Malheureusement, peu de recherches se sont penchées sur la comparaison entre les interventions sylvicoles innovatrices (rétention variable, coupe partielle, etc.) ou des techniques de préparation de terrain (brûlage dirigé, scarifiage, etc.) et ceux des feux de forêts. Toutefois, les quelques études qui comparent les effets des brûlages dirigés et les différents niveaux de rétention indiquent que ces pratiques peuvent atténuer certaines différences observées entre les coupes forestière et le feu tôt après la perturbation. Notre revue indique que comparativement aux feux, la coupe de récupération après feu peut avoir des effets significatifs sur les processus écologiques, les legs biologiques et l’abondance des espèces généralement rencontrées seulement après un incendie. L’enlèvement des arbres morts à la suite d’un incendie peut affecter la régénération des arbres, la composition du sousbois, l’abondance et la distribution du bois mort, l’habitat faunique et les propriétés du sol. Néanmoins, plusieurs de ces effets sont spécifiques au site. Par conséquent, il est nécessaire de déployer des efforts de recherche additionnels afin de soutenir les décisions d’aménagement et l’élaboration des politiques.

À l’échelle du paysage, la principale différence entre les régimes d’incendie et de récolte s’avère la distribution des classes d’âges des peuplements. La proportion des peuplements plus âgés que la période de révolution (habituellement 100 ans) tend vers zéro sous un régime de récoltes complètement normalisé, tandis qu’elle se situe autour de 35% sous un régime d’incendies dont la période de révolution est similaire. Cette différence fondamentale donne lieu à une perte significative des forêts comportant des stages avancés de succession dans les paysages aménagés, ce qui affecte les organismes qui sont essentiellement associés à de tels peuplements. Fait intéressant, puisque la coupe forestière n’est pas en mesure de recréer les conditions généralement retrouvées dans les jeunes peuplements incendiés, les paysages sous l’influence de la récolte seront également caractérisés par une réduction des peuplements en mesure de remplacer le rôle écologique des jeunes peuplements incendiés. Malheureusement, seulement quelques études ont effectué la comparaison empirique des effets des feux de forêts et de la récolte à l’échelle du paysage sous des périodes de révolution similaires. Néanmoins, la recherche démontre que les incendies produisent habituellement des paysages plus hétérogènes que des coupes à blanc, incluant plus d’îlots résiduels. Les incendies possèdent également une forme plus complexes et des bordures qui sont plus graduelles que les coupes à blanc.

En conclusion, notre revue a révélé deux principaux défis auxquels font face les gestionnaires forestiers afin de générer des effets écologiques similaires à ceux produits lors d’un incendie. D’abord, les gestionnaires ont besoin d’améliorer les pratiques forestières dans le but de minimiser les différences observées entre les jeunes peuplements coupés et les jeunes peuplements incendiés, particulièrement en ce qui concerne les débris ligneux grossiers et les conditions au sol. Ensuite, les gestionnaires doivent maintenir au sein des paysages aménagés des peuplements forestiers dont la composition et la structure sont similaires à celles retrouvées dans des peuplements matures et surmatures. De tels peuplements peuvent occuper une portion significative des paysages affectés par le National Council for Air and Stream Improvement feu. Ceci peut impliquer le rallongement de la période de révolution d’une certaine portion des peuplements au sein des paysages aménagés ou alors nécessiter l’application de méthodes de récolte innovatrices qui peuvent recréer la structure et la composition des arbres caractéristiques des stages avancés de succession. Cette revue conclue en identifiant les besoins de recherche future qui sont susceptibles d’aider à faire face à ces défis.

For decades, many have hypothesised that the effects of harvesting and wildfire differed significantly and that this would have significant effects on ecosystem processes and biodiversity. However, it is only recently that an appreciable amount of scientific data has emerged on this topic. In this report, we present our review of the similarities and differences between the ecological effects of fire- and harvesting-induced disturbances that have been noted in the scientific literature. Comparisons of the effects of these disturbances on numerous forest attributes (coarse woody debris, soil nutrients, productivity, plant diversity, wildlife response) are presented at two distinct spatial scales: stand and landscape.

At the stand scale, our review noted significant differences between harvesting and wildfire early after disturbance. Structurally, young post-fire stands are characterized by more snags, less downed woody debris, and significantly thinner forest floors than logged sites. Additionally, while both disturbances generate a pulse of extractable nutrients, the intensity of the pulse is greater after wildfire than clearcut harvesting and an increase in soil pH is observed after fire as opposed to little change or a slight decrease after harvesting.

Early after disturbance, biodiversity elements significantly differ between burned and logged sites. Dissimilar understory vascular and non-vascular communities generally colonize burned and logged sites, although differences are usually a question of abundance rather than species absence/presence. As compared to fire, faunal assemblages, be it mammals, invertebrates or birds, all seem to respond differently to harvesting. Among these faunal groups, species specifically associated with snags were the most likely to show a contrasting response to harvesting- and wildfire-induced disturbances.

Tree species respond differently to fire- and harvesting-induced disturbances, with harvesting favouring the establishment of deciduous species (notably trembling aspen, Populus tremuloides) and of coniferous tree species not adapted to fire such as balsam fir (Abies balsamea). Furthermore, there are commonly more residual deciduous trees in clearcuts than in fires. Because of this and the differential response of tree species to these two types of disturbances, divergent successional patterns with respect to overstory tree species compositions can be observed in burned and harvested stands. While we noted some variability among studies, stand and tree productivity are generally similar in burned and logged sites.

When the effects of harvesting- and wildfire-induced disturbances are compared at longer temporal scales, our review noted that most forest attributes that were reported as dissimilar early after disturbance converged a few decades post-disturbance. Nonetheless, thicker forest floors observed after logging as compared to fire appear to persist numerous decades after disturbance. Additionally, while faunal communities do become less different as time passes, late in succession, some species present in burned stands are either significantly less abundant or absent in similarly aged logged stands. Finally, several studies warn that while the effects of wildfire- and harvesting-induced disturbances do not significantly differ after a few decades, there is some concern about the ability of harvesting-induced disturbances to recreate the full range of natural variability observed during post-fire stand succession.

Unfortunately, little research has compared the effects of alternative silvicultural interventions (partial retention, partial cutting, etc.) or site preparation techniques (controlled burning, scarification, etc.) to the effects of wildfires. However, the few studies comparing the effects of post-logging control burns and different levels of retention indicate that these practices may attenuate some of the differences observed early after disturbance. Our review indicates that as compared to wildfire alone, salvage logging can have significant effects on ecological processes, biological legacies and the abundance of species commonly encountered only after fire. Removal of fire-killed trees can affect tree regeneration, understory composition, the abundance and distribution of dead wood, wildlife habitat, and soil properties. Nonetheless, many of these effects are site-specific; hence, additional investments in research are needed to support management decisions and policy development.

At the landscape scale, the main difference between fire and harvesting regimes is the distribution of stand age classes. The proportion of stands older than the rotation period (usually 100 yrs) tends toward zero under a fully regulated harvesting regime, while it is around 35% under a fire regime of similar rotation period. This fundamental difference results in a significant loss of advanced seral stage forests in managed landscapes, thereby affecting organisms that are primarily associated with such stands. Interestingly, since harvesting-induced disturbances are unable to recreate the conditions commonly found in young burned stands, landscapes under the influence of harvesting will also be characterized by a reduction of stands capable of replacing the ecological role of young burned stands within landscapes. Unfortunately, only a few studies have empirically compared the effects of wildfire and harvesting at the landscape scale under similar rotation periods. Nonetheless, research demonstrates that fires usually produce more heterogeneous landscapes than clearcuts, with more remnant islands. Fires are also more complex in shape, and have edges that are more gradual than clearcuts.

In conclusion, our review reveals two main challenges faced by forest managers in order to generate similar ecological effects as produced by fire. First, managers need to improve management practices in order to minimize the differences observed between young post-harvest stands and young post-fire stands, particularly with respect to coarse woody debris and soil conditions. Second, managers need to maintain some areas with the tree species composition and structural attributes characteristic of over-mature fire-origin stands. Such stands can occupy a significant portion of fire-mediated landscapes. This may necessitate lengthening the rotation period of a certain proportion of stands within managed landscapes or may require the application of alternative harvesting methods that can recreate the structure and tree composition characteristic of advanced seral stage stands. This review concludes by identifying future research needs that might help meet these challenges.

Rock outcrops in the boreal forest of Quebec can show either of two different states: a forested state with >25% tree cover, and an unforested state (<25% tree cover). We tested three different hypotheses that might explain the co-occurrence of forested and unforested rock outcrops: (1) differences in bedrock geology, with unforested outcrops associated to bedrock types inimical to tree growth; (2) unforested outcrops as recently disturbed sites undergoing secondary succession towards a forested state; (3) unforested outcrops as an alternative stable state to forested outcrops, induced by post-fire regeneration failure. Digitized forest inventory maps were used along with bedrock geology maps and time-since-fire maps to compare forested and unforested outcrops for bedrock geology type and date of the last fire. Field surveys were conducted on 28 outcrops (14 forested, 14 unforested) to gather information regarding tree species composition and site characteristics (thickness of the organic matter layer, percent cover of lichens, mosses and ericaceous shrubs). None of the three hypotheses explain the co-occurrence of forested and unforested rock outcrops in the boreal forest of Que´ bec. Both outcrop types occur on the same bedrock geology types. Unforested outcrops are not recently disturbed sites in early-successional states, as no clear distinction could be made in tree species composition and date of the last fire between the two outcrop types. Forested and unforested outcrops are not alternative stable states, as unforested outcrops are unstable and cannot maintain themselves through time in the prolonged absence of fire. Hence, unforested rock outcrops could be viewed as degraded, diverging post-fire types maintained by the late Holocene disturbance regime, characterized by high fire frequencies.

Assessment of the impacts of future climate change on the boreal forest and forest–tundra biomes relies on a clear understanding of their past dynamics. Fire history information recorded in lake and peat sediments can be retrieved by counting charcoal particles on pollen slides, although it is still debated whether this is reliable at the scale of the watershed (i.e. local scale). Knowing that proportionately larger charcoal particles tend to settle closer to the fire compared to smaller particles, a new method of quantifying microscopic charcoal on pollen slides is presented, taking into account the size distribution of the charcoal fragments in each sample of a sediment core (the CSD method). The late-Holocene fire history of the surroundings of a small subarctic lake was reconstructed using this method and compared with results from four other methods (macroscopic charcoal counts, charcoal concentration, charcoal : pollen ratio, charcoal : Picea ratio). All methods were tested for accuracy by comparison with the fire history of the watershed reconstructed by dendrochronology and radiocarbon-dated soil charcoal. Only the CSD method allowed separation of local-scale fire episodes from background noise attributable to long-distance dispersal.

Anatomical identification of soil charcoal fragments was used to reconstruct the pre?fire vegetation composition of a tree line site that burned ca 930 cal. AD in northern Québec, Canada. Soil charcoal was also used as a proxy to estimate black spruce Picea mariana palaeo?cover. The site (a low?elevated hilltop) is presently devoid of spruce trees and dominated by dwarf birch Betula glandulosa, lichens, ericaceous shrubs (Ledum decumbens, Vaccinium vitis?idaea) and sedges. In contrast, black spruce dominated before the fire with an understory of Empetrum nigrum and Vaccinium vitis?idaea. Pre?fire black spruce cover was estimated at 32%, giving an indication of the potential for warming?induced natural reforestation of the forest?tundra.

Aim Present northern distribution limit of jack pine (Pinus banksiana Lamb.) follows the northern limit of continuous open boreal forest in western Canada, but not in eastern Canada where it is located further south. We tested the hypothesis that fire plays a more important role than climate in explaining the present position of the northern distribution limit of jack pine.

Location An experimental jack pine plantation was set up in 1992, c. 300?km north of the present distribution limit of the species, in the Boniface river area of northern Québec (57°43??N, 76°05??W).

Methods Climate and fire data were used to compare sites at and north of the present distribution limit of jack pine. In 2001, surviving individuals from the plantation were measured (total height, annual shoot elongation, basal diameter, and presence/absence of cones).

Results Climate data from the ten weather stations used in this study did not show major differences. The northern limit of jack pine distribution is closely associated with the occurrence of fires larger than 200?ha. Survival of the planted jack pines was 31%. About 25% of the surviving pines qualified as normal, single?stem individuals; the others were slightly uprooted and/or showed marks of erosion or foraging. Cones were produced, although no viable seeds were found.

Main conclusions The low number of degree?days above 5?°C at the plantation site could explain why the seeds were not viable. However, such climate conditions are not sufficient to prevent growth, as was shown by annual shoot elongation measurements. Most of the surviving jack pines from the Boniface river plantation are relatively healthy and follow a normal developmental programme. Low fire frequency and small fire size are amongst the main factors that prevented P. banksiana from migrating further north or east following deglaciation in northern Québec and Labrador.

Résumé :

La production annuelle moyenne de graines est proportionnelle à la surface terrière pour les arbres composant la canopée. Cependant, il reste à démontrer que des individus croissant sous couvert produisent moins de graines que prévu (en fonction de leur taille) en raison de la faible disponibilité de lumière. La production de cônes a été examinée pour le sapin baumier (Abies balsamea (L.) Mill.) et l'épinette blanche (Picea glauca (Moench) Voss) en 1998 et pour le sapin baumier en 2000 dans l'ouest du Québec. Les arbres étudiés poussaient sous couvert, près ou loin de la bordure forestière, ou (pour un site) faisaient partie d'une plantation. Un modèle très simple de transmission de la lumière à travers la canopée de peuplier faux-tremble (Populus tremuloides Michx.) et à travers les troncs en bordure de la forêt a été développé afin de quantifier l'effet de la disponibilité de lumière sur la production de cônes. L'augmentation de disponibilité de lumière près d'une bordure (par exemple une coupe forestière récente) entraîne un doublement de la production de cônes chez les arbres croissant sous couvert. La hauteur minimale pour la production de cônes chez des arbres croissant sous couvert et loin de la bordure forestière est d'environ 10 m pour le sapin baumier et 14 m pour l'épinette blanche, ces valeurs diminuant près de la bordure. En comparaison, la hauteur minimale pour la production de cônes pour les épinettes blanches d'une plantation (lumière = 100%) est d'environ 3 m. Une augmentation de la variance expliquée est obtenue en tenant compte de la disponibilité de lumière.

Abstract

Mean annual seed production is assumed to be proportional to basal area for canopy trees, but it is not known if subcanopy trees produce fewer seeds than expected (given their size) because of low light availability. Ovulate cone production was examined for balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) in 1998 and for balsam fir in 2000 in western Quebec using subcanopy stems, near or far from forest edges, or (at one site) planted white spruce trees in fully open conditions. A very simple light model for transmission through mature trembling aspen (Populus tremuloides Michx.) crowns and through boles near forest edges was developed to account for the effect of light receipt on cone production. The enhanced light near forest edges (e.g., recent clearcuts) leads to about a doubling of cone production for subcanopy stems. The minimum subcanopy height for cone production far from an edge is about 10 m for balsam fir and 14 m for white spruce, with these minima decreasing near edges. By contrast, the minimum height for white spruce in a plantation (full light) is about 3 m. Accounting for light receipt leads to an increase in the explained variance © 2008 NRC Canada.

Remnant tree stands left intact following a disturbance constitute the sole seed banks available for regeneration of coniferous species that neither bear serotinous cones nor reproduce vegetatively. The success of regeneration of tree species on these disturbed sites is, therefore, dependent on the distance from potential seed sources. The regeneration of balsam fir (Abies balsamea (L.) Mill.), white spruce (Picea glauca (Moench) Voss) and white cedar (Thuja occidentalis L.) was studied at two sites in Quebec's southwestern boreal forest in order to quantify the influence of remnant stands on spatial distribution of regeneration. The first site is located in an area that burned in 1944 while the second site is located in an area that was clear-cut in the mid-1980s. Canonical correspondence analyses were used to determine the respective contributions of environmental data and spatial variables to the pattern of spatial distribution of regeneration. The results reveal that distance from a remnant stand is the most important variable in explaining spatial distribution of regeneration when compared to environmental variables such as soil type, drainage, slope and altitude. The plots of regeneration density against distance from a remnant stand for both the burned site and logged site show that regeneration density decreases abruptly with distance from a remnant stand. Furthermore, spatial autocorrelation analyses (Moran's I) indicate that even small remnant zones can significantly influence the pattern of spatial distribution of regeneration for the three species studied. The results presented here suggest that where preestablished regeneration is not abundant enough, alternative silvicultural systems such as strip clear-cutting or seed-tree systems could be used instead of cuts with protection of regeneration and soils (CPRS). (C) 2001 Elsevier Science B.V. All rights reserved. © 2002 Elsevier B.V. All rights reserved.