Impact à court terme d'une coupe avec protection de la régénération sur la gélinotte huppée (Bonasa umbellus) en forêt boréale

1998 ◽  
Vol 28 (3) ◽  
pp. 468-477 ◽  
Author(s):  
Christian Dussault ◽  
Réhaume Courtois ◽  
Jean Ferron
Keyword(s):  
Populus Tremuloides ◽  
Basal Area ◽  
Total Density ◽  
Canopy Closure ◽  
Betula Papyrifera ◽  
Ruffed Grouse ◽  
Bonasa Umbellus ◽  
Short Term ◽  
Paper Birch ◽  
Deciduous Shrubs

We studied the short-term impact of cutting with the protection of regeneration (CPR) on ruffed grouse (Bonasa umbellus) and its habitat. Drumming males were surveyed in the boreal forest of western Quebec between 1990 and 1994 in 5 control stands and 10 stands that were cut in 1992. Cutting caused a 50% decline in total density and basal area of trees. In harvested stands, shrubs were less abundant than in control stands. Lateral cover between 1 and 2 m and canopy closure were also lower in cut stands. In the harvested stands, the density varied between 14.1 and 22.6 drummers/km2 between 1990 and 1992 before the CPR. In 1993, density declined to 10.1 but was reestablished at 21.5 in 1994. Densities did not differ significantly before or after the CPR nor between cut and uncut stands (p > 0.05). After the CPR, the grouse generally established their drumming sites in the periphery of cut areas. There they found lateral cover and canopy closure similar to those measured in control stands by choosing sites where deciduous shrubs were more abundant than in the remainder of the stand. However, the characteristics of the tree stratum were not optimal; their overall density, that of Betulaceae, and that of Salicaceae were higher near drumming sites located in control stands than those in harvested stands. In harvested stands, drumming sites had a lower total basal area of trees, and namely that of deciduous trees, than in control sites. To maintain ruffed grouse populations immediately after cutting in mixed and deciduous stands of public lands, we suggest that CPRs be in 15-ha blocks while maintaining a basal area of at least 7.5 m2/ha, half of which should be in trembling aspen (Populus tremuloides Michx.) and paper birch (Betula papyrifera Marsh.).

scholarly journals Contrasting Release Approaches for a Mixed Paper Birch (Betula papyrifera)–Quaking Aspen (Populus tremuloides) Stand

2008 ◽  
Vol 25 (3) ◽  
pp. 124-132 ◽  
Author(s):  
Eric K. Zenner ◽  
Klaus J. Puettmann
Keyword(s):  
Populus Tremuloides ◽  
Basal Area ◽  
Complete Removal ◽  
Quaking Aspen ◽  
Betula Papyrifera ◽  
Mixed Stands ◽  
Early Release ◽  
Paper Birch ◽  
Area And Volume

Abstract Early release from competitors can be used to influence the species composition, quality, and rate of development of young stands. Release strategies can vary in intensity, ranging from complete removal of competitors and infrequent future entries (early, heavy, infrequent [EHI]) to lighter entries that are repeated more frequently (early, light, often [ELO]). It is unclear, however, which strategy is more successful for producing high-quality birch sawtimber (Betula papyrifera Marsh.) in mixed stands with aspen (Populus tremuloides Michx.). We evaluated the effects of various release intensities on the growth and mortality of a 16–18-ft-tall natural aspen–paper birch stand in Minnesota following density reductions from 1,500–3,000 trees ac−1 (trees per acre [TPA]) to 750 (ELO750), 500 (EHI500), and 250 (EHI250) TPA. After 6 years, paper birch was overtopped by aspen and contributed only 14% of basal area in control plots, but it occupied all diameter classes and contributed 77–87% of basal area in release plots. The basal area and volume of all paper birch and of only paper birch crop trees (100 largest TPA) were highest in lightly released ELO750 and lowest in control plots. Growth of mean quadratic diameter, basal area, and volume of paper birch was 2–3 times higher in release plots but independent of release intensity. Early release is necessary to maintain paper birch dominance, but there is no short-term advantage among treatment intensities. Long-term growth simulations using the Forest Vegetation Simulator suggest that merchantable timber production was unaffected by release strategy but that the EHI250 strategy produced the most birch sawtimber (40 times as much as in ELO750).

Consequences of elevated carbon dioxide and ozone for foliar chemical composition and dynamics in trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera)

2001 ◽  
Vol 115 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Richard L. Lindroth ◽  
Brian J. Kopper ◽  
William F.J. Parsons ◽  
James G. Bockheim ◽  
David F. Karnosky ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Chemical Composition ◽  
Populus Tremuloides ◽  
Elevated Carbon Dioxide ◽  
Betula Papyrifera ◽  
Trembling Aspen ◽  
Paper Birch

Productivity of aspen forests in northeastern Minnesota, U.S.A., as related to stand composition and canopy structure

2001 ◽  
Vol 31 (6) ◽  
pp. 1019-1029 ◽  
Author(s):  
Christopher B Edgar ◽  
Thomas E Burk
Keyword(s):  
Populus Tremuloides ◽  
Vertical Structure ◽  
Canopy Structure ◽  
Abies Balsamea ◽  
Basal Area ◽  
Balsam Fir ◽  
Annual Increment ◽  
Tree Species Composition ◽  
Residual Variation ◽  
Paper Birch

Relationships among stand composition, stemwood productivity, and canopy structure were investigated for 55 study areas in northeastern Minnesota. Tree species composition among study areas was deliberately allowed to vary. Aspen, primarily quaking (Populus tremuloides Michx.) and to a lesser degree bigtooth (Populus grandidentata Michx.), was a significant component of every study area. The two most common associates were paper birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill.). Productivity was defined as mean annual increment of tree stemwood volume and ranged from 3.3 to 12.6 m3·ha–1·year–1. A multiple-regression approach was used to investigate the relationships between productivity, stand composition, and canopy structure. Base models relating productivity to aspen site index, aspen cohort age, and total basal area were developed. Measures of stand composition and canopy vertical structure were added to the base models, and their significance in explaining residual variation in productivity was tested. Productivity was found to be negatively correlated with stand composition and canopy vertical structure, with all other factors held constant. Pure aspen and single-canopied stands were expected to be the most productive. Exceptions were present in the data: the two most productive stands were vertically stratified, aspen – balsam fir – paper birch mixtures.

Cydia strobilella (Lepidoptera: Tortricidae): antennal and behavioral responses to host and nonhost volatiles

2002 ◽  
Vol 134 (6) ◽  
pp. 793-804 ◽  
Author(s):  
C. Bédard ◽  
R. Gries ◽  
G. Gries ◽  
R. Bennett
Keyword(s):  
Populus Tremuloides ◽  
Betula Papyrifera ◽  
Populus Balsamifera ◽  
Black Cottonwood ◽  
Acer Macrophyllum ◽  
Host Seeking ◽  
Baited Traps ◽  
Seed Cone ◽  
Electroantennographic Detection ◽  
Paper Birch

AbstractFemale spruce seed moths, Cydia strobilella (L.) (Lepidoptera: Tortricidae), oviposit on seed cones of most North American spruces (Picea spp.) (Pinaceae) at the time of pollination, and larvae feed on seeds in the maturing cones. We tested the hypothesis that host-seeking moths respond to volatiles from both host and nonhost trees. In coupled gas chromatographic – electroantennographic detection (GC–EAD) analyses of extracts of spruce seed cone volatiles, > 17 compounds elicited antennal responses from male and female C. strobilella. A blend of seven compounds, including (−)-α-pinene and (−)-β-pinene, α-longipinene and α-humulene, Z3-hexenol, methyl eugenol, and cymen-8-ol, was more attractive to female C. strobilella in laboratory bioassay experiments than the complete seed cone volatile blend, containing these compounds at equivalent quantities and ratios. In GC–EAD analyses of volatile extracts from nonhost angiosperm trees, EAD-activity was associated with compounds present in (almost) every volatile source, including trembling aspen, Populus tremuloides (Michx.) (Salicaceae), paper birch, Betula papyrifera (Marsh.) (Betulaceae), black Cottonwood, Populus balsamifera trichocarpa (Torr. and Gray) (Salicaceae), and bigleaf maple, Acer macrophyllum (Pursh.) (Aceraceae). In a field experiment in the interior of British Columbia, the antennally active nonhost aldehydes, alcohols, and (±)-conophthorin all reduced captures of male C. strobilella in pheromone-baited traps. Collectively, our data suggest that host selection by C. strobilella is mediated, in part, by semiochemicals from both host and nonhost trees.

scholarly journals Birch (Betula papyrifera) × white spruce (Picea glauca) interactions in mixedwood stands: implications for management

2013 ◽  
Vol 59 (No. 4) ◽  
pp. 137-149 ◽  
Author(s):  
Ch.D.B. Hawkins ◽  
A. Dhar
Keyword(s):  
Regression Analysis ◽  
Picea Glauca ◽  
Mixed Model ◽  
Basal Area ◽  
White Spruce ◽  
Betula Papyrifera ◽  
Vegetation Control ◽  
Mixed Model Anova ◽  
Paper Birch ◽  
The Impact

Current British Columbia forest regulations drive the regeneration management towards pure conifer stands rather than remaining in a mixed-species condition. This approach may result in unnecessary vegetation control. The main objective of this investigation was to study the impact of variable paper birch densities on white spruce growth in 15&ndash;20 years old stands for management implications. Regression analysis was used to examine the effect of birch density and two competition indices to predict spruce growth. A mixed model ANOVA showed that spruce mean annual DBH and basal area increment differed significantly among sites and density. From the regression analysis it appears that birch density up to 4,000 stems&middot;ha<sup>&ndash;1</sup> had no significant influence on spruce growth which is much higher than the current BC reforestation guideline (1,000 stems&middot;ha<sup>&ndash;1</sup> broadleaves). Similarly, birch relative density index (RDI) had to exceed 3 to affect spruce DBH growth significantly on all sites except one. On most sites, spruce had a larger DBH than birch. Our results also suggest that rather than following the current broadcast approach to vegetation management, a targeted approach could enhance forest productivity and stand diversity. &nbsp;

scholarly journals Effects of a Short-Term Trampling Experiment on Alpine Vegetation in the Tatras, Slovakia

2021 ◽  
Vol 13 (5) ◽  
pp. 2750
Author(s):  
Veronika Piscová ◽  
Michal Ševčík ◽  
Juraj Hreško ◽  
František Petrovič
Keyword(s):  
Outdoor Recreation ◽  
Plant Cover ◽  
Short Term ◽  
Recreational Activities ◽  
Small Areas ◽  
Management Plans ◽  
Deciduous Shrubs ◽  
Negative Impacts ◽  
Potential Damage ◽  
Alpine Communities

Over the past decades, outdoor recreation in mountains has become progressively more important and as a result human induced potential damage has increased. Alpine communities are particularly susceptible to human recreational activities, such as tourist trampling. Although there are a number of studies that explicitly assess the effects of trampling on alpine communities, they do not reflect on terrains with a rich topography and the presence of more communities in very small areas. In this study, effects of short-term trampling on some alpine communities in the Tatras, the highest mountains of the Carpathians, were studied experimentally. Vulnerability to disturbance was compared among plant communities in terms of resistance and resilience, which are based on cover measurements. With proximity to trampling intensity, we found a significant decrease in plant cover and abundance of deciduous shrubs, lichens, and mosses. These results demonstrate that human trampling in alpine communities has major negative impacts on lichen and moss abundance and species richness. A short-term trampling experiment required several years of community regeneration. Therefore, management plans should discourage hiking activity off paths and restrict recreational activities.

Trypanosoma ontarioensis n.sp. and T. paddae from Corvus brachyrhynchos brachyrhynchos in Ontario, Canada, with notes on the biology of T. ontarioensis n.sp.

1982 ◽  
Vol 60 (9) ◽  
pp. 2107-2115 ◽  
Author(s):  
Patrick T. K. Woo ◽  
Cheryl M. Bartlett
Keyword(s):  
Agar Medium ◽  
Gallus Domesticus ◽  
Blood Agar ◽  
Melopsittacus Undulatus ◽  
Ruffed Grouse ◽  
Bonasa Umbellus ◽  
Southern Ontario ◽  
Corvus Brachyrhynchos ◽  
Domestic Chicks ◽  
Serinus Canarius

Two morphologically distinct trypanosomes (Trypanosoma ontarioensis n.sp. and Trypanosoma paddae) were found by the haematocrit centrifuge technique in the blood of 53% (64 of 121) of Corvus brachyrhynchos brachyrhynchos wintering in southern Ontario. Trypanosoma ontarioensis n.sp. is a small trypanosome with subterminal kinetoplast. It is monomorphic and not host specific. It was readily cultured in diphasic blood-agar medium. Two-week cultures were infective and contained dividing sphaeromastigotes, epimastigotes, and trypomastigotes. Blood trypomastigotes were detected in low numbers in the blood of inoculated birds (Corvus brachyrhynchos brachyrhynchos, Bonasa umbellus, Gallus domesticus, Melopsittacus undulatus, and Serinus canarius) at 28 and 48 days postinfection. The crows, ruffed grouse, and domestic chicks were laboratory raised while the budgerigars and canaries were from pet stores. One canary that was further examined at 180, 360, 540, 730, and 910 days postinfection still had detectable numbers of trypanosomes in its blood.

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