Search

The boreal forest ecosystem is one of the largest frontier forests of the world, providing many ecological services to society. Boreal forests are also economically important, but forest harvesting and management become increasingly difficult when one moves from south to north in boreal environments. An approach was thus developed to assess the suitability of land units for timber production in a sustainable forest management (SFM) context in the northern boreal forest of Quebec (Canada). This area includes all of Quebec's spruce--feather moss bioclimatic domain (closed forest), as well as the southern portion of the spruce-lichen bioclimatic domain (open woodland). Four criteria specific to the biophysical aspects of SFM were evaluated in 1114 land districts: physical environment, timber production capacity, forest vulnerability to fire (e.g., probability that it reaches maturity), and conservation of biodiversity. Indicators and acceptability cutoff values were determined for each selected criterion, and a sequential analysis was developed to evaluate if a land district has the potential to be sustainably managed. This analytical process led to the classification of land districts into three categories: slightly sensitive (SFM possible); moderately sensitive (SFM possible under certain conditions); and highly sensitive (SFM not possible). The results show that 354 land districts were highly sensitive, 62 due to physical constraints (7.5% of the area), 130 due to insufficient potential productivity (15.4% of the area), 92 due to insufficient potential productivity to account for the fire risk (13.8% of the area), and 70 due to an insufficient proportion of tall and dense forest habitats (7.7% of the area--biodiversity criterion). This work provides scientific background to proposing a northern limit for forest management act ivities in Quebec. The developed approach could be useful in other jurisdictions to address similar issues. Key words: northern limit of timber allocation, sustainable forest management, biophyscical conditions, boreal forest, black spruce forest. La foret boreale est l'une des plus grandes forets naturelles du monde et fournit de nombreux services ecologiques a la societe. La foret boreale est egalement economiquement importante, mais la recolte du bois et son amenagement deviennent de plus en plus difficiles a mesure que l'on progresse du sud vers le nord. Une approche a donc ete developpee pour evaluer l'adequation de districts ecologiques pour la production de bois dans un contexte d'amenagement durable des forets (ADF) dans la foret boreale du nord de la province de Quebec (Canada). Cette region inclut l'entierete du domaine de la pessiere noire a mousses (foret fermee) ainsi que la portion sud de la pessiere noire a lichens (foret ouverte). Quatre criteres specifiques aux aspects biophysiques de l'ADF ont ete evalues dans 1114 districts ecologiques : l'environnement physique, la capacite de production de bois, la vulnerabilite de la foret au feu (e.g., la probabilite qu'elle arrive a maturite) et la conservation de la biodiversite. Des indicateurs et des valeurs seuils ont ete determines pour chaque critere et une analyse sequentielle a ete developpee pour evaluer si un district a le potentiel d'etre amenage de maniere durable. Ce processus analytique a permis la classification de ces districts en trois categories, soit legerement sensibles (ADF possible), moderement sensibles (ADF possible sous certaines conditions) et fortement sensibles (ADF impossible). Les resultats montrent que 354 districts sont tres sensibles, 62 du fait de contraintes physiques (7.5 % de la superficie), 130 du fait d'une productivite insuffisante (15.4 % de la superficie), 92 du fait d'une productivite potentielle insuffisante pour permettre de tenir compte du risque de feu (13.8 % de la superficie) et 70 du fait d'une insuffisance de peuplements denses et hauts (7.7 % de la superficie--critere de la biodiversite). Ce travail fournit une assise scientifique pour proposer une limite nordique des activites d'amenagement forestier au Quebec. L'approche proposee pourrait etre utile a d'autres juridictions pour aborder des questions similaires. Mots-cles: limite nordique des forets attribuables, amenagement forestier durable, conditions biophysiques, foret boreale, foret d'epinette noire., Introduction The boreal forest ecosystem is one of the largest frontier forests of the world (Potapov et al. 2008). On a global scale, this ecosystem provides several key provisioning and [...]

Abstract: Conifer-regeneration failure is often observed on sites invaded by ericaceous shrubs. In northeastern Quebec, Canada, these sites are frequently characterized by dense Kalmia angustifolia L.--Rhododendron groenlandicum (Oeder) K.A. Kron [...]

Many countries around the world manage forest lands composed of commercially productive and nonproductive forest types. Large forest areas are situated in northern, alpine, and semi-arid zones. Determining the limits [...]

The boreal forest ecosystem is one of the largest frontier forests of the world, providing many ecological services to society. Boreal forests are also economically important, but forest harvesting and management become increasingly difficult when one moves from south to north in boreal environments. An approach was thus developed to assess the suitability of land units for timber production in a sustainable forest management (SFM) context in the northern boreal forest of Quebec (Canada). This area includes all of Quebec's spruce - feather moss bioclimatic domain (closed forest), as well as the southern portion of the spruce-lichen bioclimatic domain (open woodland). Four criteria specific to the biophysical aspects of SFM were evaluated in 1114 land districts: physical environment, timber production capacity, forest vulnerability to fire (e.g., probability that it reaches maturity), and conservation of biodiversity. Indicators and acceptability cutoff values were determined for each selected criterion, and a sequential analysis was developed to evaluate if a land district has the potential to be sustainably managed. This analytical process led to the classification of land districts into three categories: slightly sensitive (SFM possible); moderately sensitive (SFM possible under certain conditions); and highly sensitive (SFM not possible). The results show that 354 land districts were highly sensitive, 62 due to physical constraints (7.5% of the area), 130 due to insufficient potential productivity (15.4% of the area), 92 due to insufficient potential productivity to account for the fire risk (13.8% of the area), and 70 due to an insufficient proportion of tall and dense forest habitats (7.7% of the area - biodiversity criterion). This work provides scientific background to proposing a northern limit for forest management activities in Quebec. The developed approach could be useful in other jurisdictions to address similar issues. [ABSTRACT FROM AUTHOR]

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

It is necessary to evaluate how large seedling stock, used as an alternative to chemical herbicide for vegetation management, interacts with the timing of mechanical release (MR) and if use of such stock offers a broader window of intervention for release than conventional stock. Such a context is present in Quebec (Canada), where chemical herbicides were banned from use on public lands in 2001. We thus evaluated the impact of delaying MR on the performance of large spruce seedlings established in a gradient of vegetation zones and competition environments. Fourteen experiments were conducted in Picea glauca or P. mariana plantations in the temperate hardwood (TH), temperate mixedwood or boreal mixedwood vegetation zones. On each site, we established a completely randomized block design with 5–8 replicates, each divided into four plots: (1) control; (2) MR applied the year during which light availability to the planted seedlings averaged 60 per cent of full sunlight (EARLY); (3) MR at EARLY + 1 year (LATE1); and (4) MR at EARLY + 2 years (LATE2). Vegetation data collected in controls 8 years after MR was submitted to a correspondence analysis to group the sites according to their competing species dominance. Seedling responses to the timing of MR, 5–8 years after treatment, varied across competing vegetation dominance, vegetation zone or a combination of both. On sites where intolerant hardwoods were dominant, postponing MR 1 year after light availability had reached 60 per cent of full sunlight had a positive effect on seedling dimensions, especially in the TH zone. However, the LATE2 treatment resulted in significant stem volume losses on these sites. Whereas treatment effects were limited on ericaceous dominated sites, MR promoted seedling growth on sites dominated by shrub/herbaceous species, with no difference between EARLY, LATE1 and LATE2. [ABSTRACT FROM PUBLISHER]

Genetic diversity was studied in four Canadian ecological populations, each corresponding to a Canadian ecozone, of Chondrostereum purpureum, including 93 isolates of various host origin. Pseudo-allelic frequencies were estimated at each of 22 putative RAPD loci by scoring for presence or absence of amplicons in haploid mycelial cultures. The analysis of the hierarchical population structure did not reveal any trend with regard to ecological or host origin. Total gene diversity (HT+ = 0.288) was mostly attributable to diversity within populations (Hst = 0.269). In addition, the AMOVA analysis detected most of the molecular variability within subpopulations (89.3%; P < 0.001) whereas a significant (7.3%; P =0.001) proportion of the gene diversity was found among subpopulations, within ecozones. The results indicate that C. purpureum is a highly heterogeneous pathogen with a continuously distributed population across Canada (Gst = 0.048) and underscore the importance of considering the population structure in the process of its registration as a microbial control agent. A genotype isolated in either central of eastern Canada (ecozones 2,4, and 5 populations) and selected for its potential as a biophytocide should be considered indigenous in any of these regions of intended use. [ABSTRACT FROM AUTHOR]

The effectiveness of manual release to favor growth and survival of black spruce seedlings was determined in eastern Quebec plantations. Up to three releases over as many consecutive years, and two weed cutting methods, were tested for two types of competing vegetation composed of either raspberry and fireweed (Squatec site) or shade intolerant deciduous trees (Lake Anna site). Five weed cutting periods, from June through October, were also tested at this last site. Seedling growth and survival were not affected by the number of releases. At theSquatec site, seedlings released with a brush cutter were 24% largerin diameter at the collar, and on average 12% higher, than untreatedseedlings after 10 years. Weed cutting during the growth season (June through September) enhanced seedling growth. At the Lake Anna site,the best growth enhancement was produced by cutting out all competing vegetation. Seedlings in these plots were 53% larger in diameter atthe collar and on average 79% higher than control seedlings. Effectsof the release treatments on height and diameter growth increased with time relative to untreated seedlings, showing that treatments had a long-lasting effect. Furthermore, a variance analysis of skewness and kurtosis coefficients was used to determine the effect of competition on the structure of seedling dimensions. After 10 years at the Squatec site, diameter and height distributions were skewed to the leftand to the right, respectively. After the same lapse of time at LakeAnna, height and diameter distributions in released plots were skewed to the right opposite to the left in untreated plots. At both experimental sites, seedling dimensions were arranged in a hierarchical manner nearly always similar between released and control plots as a result of competition effects that were lasting since the time of release. Results suggest that release effects should be examined not only on the average growth of seedlings but also on stand structure. [ABSTRACT FROM AUTHOR]