Influence de quelques défauts externes sur la stabilité des arbres face à une simulation mécanique de l'action du vent

1998 ◽  
Vol 28 (1) ◽  
pp. 123-131
Author(s):  
G Silva ◽  
J -C Ruel ◽  
M Samson ◽  
D Pin
Keyword(s):  
Populus Tremuloides ◽  
Maximum Stress ◽  
No Reduction ◽  
Abies Balsamea ◽  
The Other ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
Wind Action ◽  
Significant Difference ◽  
Standing Trees

A simulation of wind action was achieved to test the influence of some external defects on the resistance of standing trees of balsam fir (Abies balsamea (L.) Mill.), yellow birch (Betula alleghaniensis Britton), and trembling aspen (Populus tremuloides Michx.). The methodology used consisted of applying a force on the tree with a winch. Every tree was filmed during winching, and the geometrically corrected images were used to compute displacement. Balsam fir trees tended to break more than uproot, and in most cases, breakage occurred at the crack level. Even though maximum turning moment did not differ between control and defective balsam fir trees, a significant difference was found for maximum stress, showing a reduction in resistance associated with cracks. No reduction in resistance could be seen for the other species, but trees were relatively young and care should be taken before extending these results to older trees.

Dynamique de la sapinière à bouleau jaune de l'est après une épidémie de tordeuse des bourgeons de l'épinette

1999 ◽  
Vol 75 (3) ◽  
pp. 515-534 ◽  
Author(s):  
Pierre Pominville ◽  
Stéphane Déry ◽  
Louis Bélanger
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
The Other ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
White Birch ◽  
Yellow Birch ◽  
Mixed Stands ◽  
The Dead

An outbreak of spruce budworm, Choristoneura fumiferana (Clem.), occurred between 1974 and 1987, in Quebec, in the eastern balsam fir, Abies balsamea (L.) Mill, - yellow birch, Betula alleghaniensis Britton, ecoclimatic sub-domain. The effect of this disruption has been assessed in mesic balsam fir stands killed during the outbreak, in mesic balsam fir stands partially damaged and in the following stands, also partially damaged: mesic yellow birch – balsam fir stands, mesic white birch, Betulapapyrifera Marsh., - balsam fir stands, mesic balsam fir – yellow birch stands, mesic balsam fir – white birch stands and xeric balsam fir stands. To that effect, surveys were led before, immediately after, and about five years after the outbreak in two blocks that have not been protected with insecticides. These blocks, located in Charlevoix and in Shipshaw management units, are second growth stands originating from clearcuts which occured about 50 years ago. Approximately five years after the outbreak, abundant coniferous regeneration was found everywhere except in the mesic yellow birch –balsam fir stand and in the dead mesic balsam fir stand, where softwood represented less than 50% of the regeneration. On the other hand, young softwood stems were located under the regeneration of white birch and of mountain maple, Acer spicatum Lam, in dead balsam fir stands, in balsam fir – white birch stands, as well as in living balsam fir stands and under mountain maple in yellow birch – balsam fir stands and in balsam fir – yellow birch stands. Our age structures indicate that softwood advance growth was relatively rare in these stands. Thus, during the opening of the canopy by the spruce budworm, intolerant hard-woods and shrubs invaded the still available microsites. In the dead balsam fir stands, stocking of the dominant hardwood regeneration stems is equivalent to that of softwood. Thus, dead balsam fir stands are turning to mixed stands. Xeric stands will remain softwood stands since they show luxuriant softwood regeneration dominating in height. In the other stands, we will have to wait the harvest period before we can adequately assess succession.

Succession forestière après feu dans la sapinière à bouleau jaune du Bas-Saint-Laurent, Québec

1997 ◽  
Vol 73 (6) ◽  
pp. 702-710 ◽  
Author(s):  
Louis Archambault ◽  
Jacques Morissette ◽  
Michèle Bernier-Cardou
Keyword(s):  
Populus Tremuloides ◽  
Sugar Maple ◽  
Abies Balsamea ◽  
Acer Rubrum ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
Vegetation Composition ◽  
White Birch ◽  
Yellow Birch ◽  
Hardwood Species

Forest successions following a forest fire that occurred in 1932 were studied on mesic sites of the boreal mixedwood forest of the Bas-Saint-Laurent region of Quebec, Canada. Physiographic, soil and vegetation data were collected in 28 ecosystems distributed on a topographic gradient. The vegetation composition of the main canopy, 64 years after the fire, varied according to topographic situation. The proportion of tolerant hardwood species (yellow birch (Betula alleghaniensis Britton), sugar maple (Acer saccharum Marsh.), red maple (Acer rubrum L.)) increased toward upper slopes whereas it was the opposite for coniferous species (white spruce (Picea glauca [Moench] Voss), balsam fir (Abies balsamea [L.] Mill.)), as their proportion increased toward lower slopes. Intolerant hardwood species (white birch (Betula papyrifera Marsh.), trembling aspen (Populus tremuloides Michx.)) were abundant in all ecosystems. The distribution pattern of regeneration density and stocking of tolerant hardwoods and conifers was similar to that of the main canopy. The majority of commercial species, including tolerant species, established rapidly after the fire. Only eastern white cedar (Thuya occidentalis L.), which is a species typical of late succession, did not grow back. Ten years after the fire, 78% of the sampled dominant trees were established. Competition caused by mountain maple (Acer spicatum Lam.) did not seem to be as important after fire compared with the situation after clearcutting. Results showed that after the elimination of intolerant species, the vegetation composition should evolve toward the potential vegetation (climax) of the toposequence, that is, the sugar maple - yellow birch type on upper slopes, the balsam fir - yellow birch type on midslopes and the balsam fir - yellow birch - cedar type on lower slopes. Key words: succession, fire, yellow birch, balsam fir, mountain maple.

scholarly journals Gap dynamics in Balsam Fir, Abies balsamea - Yellow Birch, Betula alleghaniensis, forests of Québec

2009 ◽  
Vol 123 (2) ◽  
pp. 117 ◽  
Author(s):  
Rémi Hébert ◽  
Jean Huot
Keyword(s):  
Natural Regeneration ◽  
Forest Cover ◽  
Abies Balsamea ◽  
Woody Species ◽  
Balsam Fir ◽  
Regeneration Process ◽  
Betula Alleghaniensis ◽  
Gap Dynamics ◽  
Yellow Birch ◽  
Gap Characteristics

To determine if gap dynamics can play an important role in the natural regeneration process of Balsam Fir (Abies balsamea)-Yellow Birch (Betula alleghaniensis) forests and to determine the effects of gap characteristics on regenerating woody species, we sampled 119 gaps from 64 forest stands in La Mauricie National Park. Gaps averaged 184.5 m² in size. The mean gap age was 7.8 years. Gaps were usually created by broken or uprooted trees and only rarely resulted from Spruce Budworm (Choristoneura fumiferana) outbreaks. We found 25 species that regenerated in the gaps or under the forest cover. When considering all species, significantly more stems/ha were in gaps than under the forest cover. Gap characteristics generally did not influence regenerating woody species. We present a comprehensive model of gap dynamics in Balsam Fir-Yellow Birch forests, starting from a dense canopy, continuing with the creation and colonization of gaps, and ending to the closure of the canopy. Gap dynamics play an important role in the natural regeneration process of Balsam Fir-Yellow Birch forests.Afin de déterminer si la dynamique par trouée peut jouer un rôle important comme processus naturel de régénération de la sapinière à Bouleau Jaune et aussi afin de déterminer les effets des caractéristiques des trouées sur la régénération, nous avons échantillonné 119 trouées dans 64 peuplements forestiers au parc national de la Mauricie. Ces ouvertures avaient une superficie moyenne de 184,5 m². L’âge moyen des ouvertures était de 7,8 ans. Elles étaient généralement créées par un arbre cassé ou déraciné. Peu d’ouvertures étaient créées par des épidémies de la Tordeuse des Bourgeons de l’Épinette. Au total, 25 espèces en régénération ont été rencontrées dans les ouvertures ou sous le couvert forestier. En considérant toutes les espèces, il y avait significativement plus de tiges/ha dans les ouvertures que sous le couvert forestier. Les caractéristiques des trouées n’influençaient généralement pas la régénération. Nous présentons un modèle complet sur la dynamique par trouée dans la sapinière à Bouleau jaune, commençant avec une canopée dense, continuant avec la création et la colonisation des trouées, et se terminant avec la fermeture de la canopée. La dynamique par trouée joue un rôle important dans le régime de perturbations de la sapinière à Bouleau jaune.

Évaluation de la coupe avec protection de la régénération et des sols comme méthode de régénération de peuplements mélangés du domaine bioclimatique de la sapinière à bouleau jaune de l'est du Québec, Canada

2000 ◽  
Vol 76 (4) ◽  
pp. 653-663 ◽  
Author(s):  
Vincent Laflèche ◽  
Jean-Claude Ruel ◽  
Louis Archambault
Keyword(s):  
Abies Balsamea ◽  
Soil Disturbance ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
Short Period ◽  
Commercial Species ◽  
Paper Birch ◽  
Growth Projection ◽  
The Impact

The effect of careful logging to preserve advance growth was studied in mixedwood stands of the balsam fir (Abies balsamea (L.) Mill.) - yellow birch (Betula alleghaniensis Britton) eco-climatic domain in eastern Quebec, Canada. The study is based on 19 sites harvested five years earlier. In each cutover, 50 sample plots have been established to quantify the abundance of regeneration five years after logging. This cutting method proved to be ineffective in limiting the invasion of competiting species such as mountain maple (Acer spicatum Lam.) and pin cherry (Prunus pensylvanica (L.), which fully occupied the sites with 25 092 and 5619 stems ha−1 respectively. Balsam fir was abundant after five years in the study area with 13 500 stems ha−1 but two thirds of the seedlings were smaller than 30 cm. Soil disturbance was minimal, probably limiting the establishment of yellow birch, which reached a density of 1416 stems ha−1 five years after logging. Height growth projection of regeneration over five years showed that competiting species should still dominate the sites. Commercial species should improve their position but would still account for only 40% of dominant stems. It is therefore unlikely that this regeneration method will be successful in bringing back the initial stand composition in a short period of time. The next stands will probably contain a high proportion of intolerant species with a dominance of paper birch (Betula papyrifera Marsh.) over yellow birch. In the near future, cleaning operations should be conducted to reduce the impact of competing vegetation and make sure that balsam fir will remain in the main canopy.

Artificial inoculation with Armillaria ostoyae in established conifers stressed by defoliation, planting, and thinning in Newfoundland

2000 ◽  
Vol 30 (11) ◽  
pp. 1758-1765 ◽  
Author(s):  
M D Piercey-Normore ◽  
J A Bérubé
Keyword(s):  
Black Spruce ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Root Infection ◽  
Armillaria Ostoyae ◽  
Significant Difference ◽  
Balsam Woolly Adelgid ◽  
Pathogenicity Tests ◽  
Mill Stand ◽  
Hemlock Looper

Armillaria ostoyae (Romagnesi) Herink causes root disease in conifers of the northern hemisphere. Pathogenicity tests of established conifer trees with A. ostoyae, has never been done in the boreal forest. Seven forest plots were selected in Newfoundland; a black spruce (Picea mariana (Mill.) BSP) plantation, a naturally regenerated black spruce stand, a balsam fir (Abies balsamea (L.) Mill.) stand with hemlock looper (Lambdina fiscellaria (Guen.)) defoliation, two balsam woolly adelgid (Adelges piceae (Ratz.)) infested balsam fir stands (thinned and unthinned sites), a balsam fir sawfly (Neodiprion abietis Harris) defoliated balsam fir stand, and an artificially defoliated black spruce stand. Roots of fir and spruce trees were inoculated with two isolates of A. ostoyae and re-examined after 2 years. The purpose of this study was to compare differences in root infection within plots for different types of host stress to examine the response of trees to controlled inoculations of A. ostoyae. There was a statistically significant difference in number of infected roots between the two isolates used as inoculum. There was significantly more root response with severity of infection within all sites except both adelgid plots. A marginally significant relationship between tree health and root infection was present in the balsam fir sawfly plot. There was a significantly larger number of infected roots associated with rhizomorphs in the naturally regenerated black spruce stand and the artificially defoliated balsam fir stand. These results suggest that stress prediposes the host tree to root infection by A. ostoyae.

Insect–host relationships influencing disturbance by the spruce budworm in a boreal mixedwood forest

2004 ◽  
Vol 34 (9) ◽  
pp. 1870-1882 ◽  
Author(s):  
V G Nealis ◽  
J Régnière
Keyword(s):  
Life Cycle ◽  
Populus Tremuloides ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Host Tree ◽  
Balsam Fir ◽  
Insect Host ◽  
Boreal Mixedwood Forest

Demographic data from a 15-year outbreak of the spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae), in a boreal mixedwood forest in Ontario, Canada, are used to interpret stand-level ecological disturbance in terms of susceptibility and vulnerability (mortality) of balsam fir (Abies balsamea (L.) Mill.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) BSP). All three host-tree species are highly susceptible for oviposition by the spruce budworm and all are suitable for completion of the budworm life cycle. Host-related differences in susceptibility arise from the degree of synchrony between spruce budworm phenology during the feeding stages and host-tree phenology. Spruce budworm density was highest on white spruce throughout the budworm's life cycle and over the course of the outbreak, but more rapid flushing and growth of current-year buds in white spruce reduced damage relative to that on balsam fir. Conversely, later flushing of current-year buds on black spruce led to a reduction in budworm density early in the season and a corresponding reduction in defoliation. The combination of high budworm densities and severe defoliation caused mortality first on balsam fir. By the end of the outbreak, 89% of the balsam fir component >10 cm DBH was eliminated compared with 49% of the white spruce in the same size class. The lower susceptibility of black spruce resulted in survival of all but the smallest size classes of that species. Nonhost species such as trembling aspen (Populus tremuloides Michx.) nearly doubled their basal area during the outbreak. The results link processes inherent in the insect–host relationship with the population ecology of the insect and the disturbance ecology of the forest.

La végétation forestière du delta de Lanoraie, Québec

1991 ◽  
Vol 69 (8) ◽  
pp. 1839-1852 ◽  
Author(s):  
L. Lamontagne ◽  
C. Camiré ◽  
C. Ansseau
Keyword(s):  
Populus Tremuloides ◽  
Acer Saccharum ◽  
Abies Balsamea ◽  
Acer Rubrum ◽  
Fagus Grandifolia ◽  
The Other ◽  
Moisture Regime ◽  
Acidic Ph ◽  
Mature Trees ◽  
Forest Sites

The vegetation and the soil characteristics of the sandy terraces of the Lanoraie Delta, Quebec, were sampled at 84 forest sites using the methods of Whittaker and Canada Soil Information System. The ordination results show that the soil moisture regime (xeric–hydric) and the pH (3.5–5.0) are the main factors responsible for the spatial distribution of the vegetation. When these results (ordination analysis) and those of the cluster analysis are superimposed, the relationship between the five vegetation groups studied and particular ecological conditions can be seen. Thus, two groups of vegetation dominated by conifers are found in the middle of the terraces. One of these is dominated by Tsuga canadensis and the other by Abies balsamea and Picea rubens. These two groups are found on podzolic, gleyed soils with a mounded microrelief, which are strongly acidic (pH < 3.5) and have a hydric–mesic moisture regime. The remaining three vegetation groups are dominated by deciduous species. Among these, two groups arise from human activities such as logging or farming. One of these is dominated by Fagus grandifolia, Acer saccharum, Acer rubrum, and Quercus rubra and is composed of mature trees. The other is dominated by Pinus strobus, Polulus grandidentata, Populus tremuloides, or Betula papyrifera and is composed of young trees. These two types occupy the edge of the terraces where the topography is flat and the soil podzolic with a moderately to slightly acidic pH (4.0–5.0) and a xeric–mesic moisture regime. Finally the third group, dominated by Acer rubrum, is found on medium acidic (pH = 4.0), gleyed soils with a hydric–mesic moisture regime. This study shows that Acer rubrum is the best suited species for sandy, acidic, and nutrient-poor sites of the Lanoraie Delta. Key words: Lanoraie Delta, multivariate analysis, vegetation classification, Acer rubrum.

Fifty years of forest dynamics following diameter-limit cuttings in balsam fir – yellow birch stands of the Lower St. Lawrence region, Quebec

2006 ◽  
Vol 36 (11) ◽  
pp. 2745-2755 ◽  
Author(s):  
Louis Archambault ◽  
Claude Delisle ◽  
Guy R Larocque ◽  
Luc Sirois ◽  
Pierre Belleau
Keyword(s):  
Forest Dynamics ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
Cover Type ◽  
Advance Regeneration ◽  
Observation Area ◽  
Winter Logging

The long-term effects of high-intensity diameter-limit cuttings conducted in the winter and summer of the 1940s and 1950s on the dynamics of softwood and mixedwood stands in southeastern Quebec were compared. Changes in composition and stand structure over a 50 year period were studied using 18 permanent sample plots located in the Lac-Métis Seigneury observation area measured in 1950, 1960, 1970, and 2003. Winter logging operations were conducted between 1942 and 1949, and summer logging operations were conducted between 1958 and 1960. The interaction between cuttings and the 1950s and 1970s spruce budworm (Choristoneura fumiferana (Clemens)) outbreaks that occurred in the area affected forest dynamics. For the two logging operation types, the most abundant softwood species observed before logging and in 2003 was balsam fir (Abies balsamea (L.) Mill.), whereas white birch (Betula papyrifera Marsh.) and yellow birch (Betula alleghaniensis Britt.) were the most abundant hardwood species. Changes in the overstory composition were more significant in the summer logging operations than in the winter ones. The softwood cover type observed before winter logging was maintained in 2003. Following summer logging, an important increase in the proportion of birch species was observed. The softwood cover type observed before logging had changed to a mixedwood cover type by 2003. Forest dynamics differences between the two types of logging were the result of interactions between the density and composition of advance regeneration, the microsite conditions after logging, and the length and severity of spruce budworm outbreaks.

Variations, selon la progression de l'hiver, dans le choix de l'habitat et du régime alimentaire chez trois groupes d'orignaux (Alces alces) en milieu agro-forestier

1986 ◽  
Vol 64 (7) ◽  
pp. 1475-1481 ◽  
Author(s):  
Robert Joyal ◽  
Claude Bourque
Keyword(s):  
Populus Tremuloides ◽  
Snow Depth ◽  
Alces Alces ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Régime Alimentaire ◽  
Trembling Aspen ◽  
Plant Composition ◽  
Core Areas ◽  
Settlement Areas

Three distinct groups of moose (Alces alces) were followed for one winter in settlement areas of northwestern Quebec to investigate changes in their choice of diet and habitat over the winter. No trend was observed in structure and plant composition of winter yards over the season. From December to March, each group used at least three different core areas intensively, these areas totalling 1.02 (first group), 1.28 (second group), and 2.48 km2 (third group). The size of the winter yards diminished in March but this decrease was not due to an increase in snow depth, which reached its maximum of 88 cm in February. The total areas used by the three groups were 1.7, 2.6, and 6.6 km2, respectively. No trend was found in the diet during the winter, except that trembling aspen (Populus tremuloides) was most heavily used by the three groups in March. Twenty-three species of browse were used but 6 species formed nearly 95% of the diet; balsam fir (Abies balsamea) and mountain maple (Acer spicatum) were almost completely absent from the diet.

scholarly journals WEEKLY RADIAL INCREMENT OF BALSAM FIR IN QUEBEC AS RELATED TO McLINTOCK'S TREE CLASSIFICATION

1963 ◽  
Vol 39 (3) ◽  
pp. 318-321
Author(s):  
J. D. Gagnon
Keyword(s):  
Abies Balsamea ◽  
Growing Season ◽  
The Other ◽  
Balsam Fir ◽  
Radial Increment ◽  
Total Height ◽  
Better Than

Radial increments of 38 balsam fir trees (Abies balsamea (L.) Mill.) differing in height, crown class and vigour, were studied to determine if their correlation with the McLintock classification was better than that with either total height, crown class, vigour class or crown ratio. Measurements at weekly intervals during the 1961 growing season have shown the superiority of the McLintock tree classification over the other four. It seems, therefore, that the interaction of the factors involved in McLintock classification is essentially valid even for very short predictions.

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