La végétation postglaciaire du Témiscamingue, Québec, durant l'épisode glaciolacustre Barlow

1989 ◽  
Vol 67 (2) ◽  
pp. 544-558 ◽  
Author(s):  
Pierre J. H. Richard ◽  
Alayn C. Larouche
Keyword(s):  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Sediment Accumulation ◽  
Abies Balsamea ◽  
Betula Papyrifera ◽  
Populus Balsamifera ◽  
Conifer Forest ◽  
General Sequence ◽  
Ice Retreat ◽  
Organic Deposits

The 14C ages of the basal organic deposits accumulated in 32 small lakes located higher than or near the altitudinal limit of proglacial Lake Barlow, in Témiscamingue, span the period between 10400 and 6490 years BP. A regional pollen zonation has been established, allowing the rejection of the 14C ages younger than 8500 years BP, as minimum ages for local ice retreat. From 10400 to 8500 BP, whatever the age of the lake, the same general sequence of vegetation has spread over the deglaciated landscapes. The initial vegetation was dominated by Picea and Larix (pollen, macrofossils) and included Quercus, Ostrya, Ulmus, and Fraxinus (pollen influxes equal or greater than what they are today) along with plants having a present-day mainly arctic distribution such as Dryas integrifolia and Silene acaulis (macrofossils). The initial proglacial vegetational environment on the islands or around Lake Barlow was thus an open conifer forest with arctic plants and groves of relatively thermophilous deciduous trees, whatever the age of the onset of sediment accumulation in the lakes studied, between 10400 and 8500 years BP. After the initial vegetation was established and within a few centuries, Betula papyrifera, Populus tremuloides, Populus balsamifera, Pinus banksiana, and Abies balsamea (macrofossils, pollen) joined the other trees around each lake, whatever the age or location.

Photosynthetic and morphological responses of white birch, balsam poplar, and trembling aspen to freezing and artificial defoliation

Botany ◽  
2013 ◽  
Vol 91 (6) ◽  
pp. 343-348 ◽  
Author(s):  
Rongzhou Man ◽  
Pengxin Lu ◽  
Steve Colombo ◽  
Junlin Li ◽  
Qing-Lai Dang
Keyword(s):  
Populus Tremuloides ◽  
Betula Papyrifera ◽  
Populus Balsamifera ◽  
Trembling Aspen ◽  
White Birch ◽  
Continuous Growth ◽  
Balsam Poplar ◽  
Warming Climate ◽  
Morphological Responses ◽  
Spring Frosts

Comparative stress resistance of 1-year-old white birch (Betula papyrifera Marsh.), balsam poplar (Populus balsamifera L.), and trembling aspen (Populus tremuloides Michx.) seedlings was evaluated after exposure to freezing or defoliation. Photosynthesis in leaves surviving freezing (−5 °C) declined immediately after treatment, but nearly fully recovered within 3 weeks. Defoliation did not significantly increase photosynthesis in the remaining leaves. Refoliation occurred after freezing that killed terminal shoots and released current buds from apical dominance, while new leaves of larger size were produced through continuous growth of terminal shoots in 50% or 100% defoliation. Freezing and complete defoliation significantly reduced diameter and height growth in all species, whereas 50% defoliation did not affect growth. These results indicate some of the physiological and morphological responses to foliage loss in broadleaved boreal species that can help to maintain growth and productivity under a warming climate, which may result in more frequent damaging spring frosts and insect defoliation.

Early winter food habits of Manitoba moose as determined by three rumen analysis methods

1982 ◽  
Vol 60 (6) ◽  
pp. 1300-1304 ◽  
Author(s):  
R. Zach ◽  
V. F. J. Crichton ◽  
J. M. Stewart ◽  
K. R. Mayoh
Keyword(s):  
Populus Tremuloides ◽  
Food Habits ◽  
Abies Balsamea ◽  
Food Habit ◽  
Dry Weight ◽  
Early Winter ◽  
Populus Balsamifera ◽  
Winter Food ◽  
Cornus Stolonifera ◽  
Game Hunting

Early winter food habits of moose (Alces alces) from Hecla Island and Manitoba game hunting area 26 in southeastern Manitoba were studied in 1978 and 1979. Twenty-five plant taxa were identified in 86 rumen samples. In decreasing order of importance, moose fed mainly on red-osier dogwood (Cornus stolonifera), balsam fir (Abies balsamea), willow (Salix spp.), mountain maple (Acer spicatum), trembling aspen (Populus tremuloides), bog birch (Betula glandulifera), and balsam poplar (Populus balsamifera). These taxa constituted about 98% of the diet by weight. Most rumens contained several of these taxa, with some containing traces of the uncommon ones. The diet of moose from the two study areas was similar, but Hecla Island moose showed a shift in diet from 1978 to 1979. The diet was not influenced by sex or age of the moose.Three methods of food habit determination were used: presence/absence, abundance score, and dry weight. All three methods yielded very similar results. Although some rumen samples had a volume of only 0.13 L, sampling volume was not significantly correlated with the number of taxa identified per sample. Gains curves showing the cumulative total number of taxa versus successive samples collected indicated that the number of samples analyzed was adequate.

scholarly journals Effects of Gypsy Moth Defoliation on Softwood and Hardwood Growth and Mortality in New Brunswick, Canada

2007 ◽  
Vol 24 (2) ◽  
pp. 138-145 ◽  
Author(s):  
Chris Richard Hennigar ◽  
David A. MacLean ◽  
Chris James Norfolk
Keyword(s):  
New Brunswick ◽  
Populus Tremuloides ◽  
Gypsy Moth ◽  
Tree Mortality ◽  
Abies Balsamea ◽  
Growth Patterns ◽  
Betula Papyrifera ◽  
Growth Reduction ◽  
White Birch ◽  
Insecticide Spray

Abstract The first major European gypsy moth (Lymantria dispar L.) outbreak occurred in central New Brunswick, Canada, on over 3,000 ha of forestland, from 2001ߝ2003. The outbreak was severe enough to result in considerable landowner concern and a privately funded aerial insecticide spray program to protect trees. Defoliation was unexpectedly severe on several tree species thought to be resistant or immune, as indicated from studies in the northeastern United States. Fifty plots (564 trees) were established and measured for standard mensurational characteristics, defoliation, and annual tree mortality, and after the cessation of defoliation, 44 trees were destructively stem analyzed to determine growth patterns. Balsam fir (Abies balsamea [L.] Mill.) with defoliation of more than 75% sustained specific volume increment reduction averaging 55% and 25% mortality after 2 years of severe defoliation. Red oak (Quercus rubra L.) sustained about 40% growth reduction, similar to results of previous studies. However, white birch (Betula papyrifera Marsh.) and trembling aspen (Populus tremuloides Michx.), with more than 75% defoliation for 2 years, sustained 43ߝ48% growth reduction, higher than in previous studies, and 4ߝ12% mortality. The gypsy moth range in Canada appears to be gradually expanding beyond previous climatic (cold winter temperature) limitations, and these results will help to predict future impacts.

scholarly journals Canopy, snow, and lichens on woodland caribou range in southeastern Manitoba

Rangifer ◽  
1996 ◽  
Vol 16 (4) ◽  
pp. 239 ◽  
Author(s):  
James A. Schaefer
Keyword(s):  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Rangifer Tarandus ◽  
Abies Balsamea ◽  
Jack Pine ◽  
Percent Cover ◽  
Woodland Caribou ◽  
Canopy Composition ◽  
Selection For ◽  
Mixed Communities

I examined the relationships among snow cover (api), lichen abundance, and canopy composition on the range of the Aikens Lake population of woodland caribou (Rangifer tarandus caribou) in southeastern Manitoba. Percent cover of forage lichens (Cladina spp.) was positively correlated with maximum total thickness and with maximum vertical hardness of api. Mixed communities of trembling aspen (Populus tremuloides), spruce (Picea spp.), and balsam fir (Abies balsamea) showed the most favourable nival conditions for caribou but had low lichen abundance; those dominated by jack pine (Pinus banksiana) were the converse. The results suggest an energetic compromise for woodland caribou when foraging for terrestrial lichens. During winter, caribou exhibited significant selection for jack pine communities whereas mixed communities were avoided.

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.

Laboratory assessment of the effect of forest floor ash on conifer germination

2010 ◽  
Vol 40 (4) ◽  
pp. 822-826 ◽  
Author(s):  
Kevin J. Kemball ◽  
A. Richard Westwood ◽  
G. Geoff Wang
Keyword(s):  
Populus Tremuloides ◽  
Forest Floor ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Abies Balsamea ◽  
White Spruce ◽  
Jack Pine ◽  
Balsam Fir ◽  
Laboratory Assessment ◽  
The Impact

Mineral soils exposed by fire are often covered by a layer of ash due to complete consumption of the forest floor (litter and duff). To assess the possible effects of ash on seed germination and viability of jack pine ( Pinus banksiana Lamb.), black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.), white spruce ( Picea glauca (Moench) Voss), and balsam fir ( Abies balsamea (L.) Mill.), a laboratory experiment was conducted using ash derived from three types of forest floor samples. The samples represented areas of high conifer concentration, high aspen concentration, and mixed aspen and conifer and were collected from five mature aspen ( Populus tremuloides Michx.) – conifer mixedwood stands in southeastern Manitoba. Ash derived from each forest floor type neither prohibited nor delayed conifer germination, except that of balsam fir. Balsam fir had significantly less germination on ash derived from forest floor samples with high aspen concentration. When corrected for seed viability, balsam fir had significantly less germination on all three ash types compared with jack pine, black spruce, and white spruce. However, the impact of ash on balsam fir is unlikely to have meaningful ecological implications, as balsam fir is a climax species and will establish in undisturbed mature forests.

Responses of ectomycorrhizal Populus tremuloides and Betula papyrifera seedlings to salinity

2008 ◽  
Vol 62 (3) ◽  
pp. 357-363 ◽  
Author(s):  
Huang Yi ◽  
Mónica Calvo Polanco ◽  
Michael D. MacKinnon ◽  
Janusz J. Zwiazek
Keyword(s):  
Populus Tremuloides ◽  
Betula Papyrifera

Effects of open-range cattle grazing on deciduous tree regeneration, damage, and mortality following patch logging

2014 ◽  
Vol 44 (7) ◽  
pp. 777-783 ◽  
Author(s):  
Jillian Kaufmann ◽  
Edward W. Bork ◽  
Michael J. Alexander ◽  
Peter V. Blenis
Keyword(s):  
Populus Tremuloides ◽  
Sustainable Forest Management ◽  
Deciduous Forest ◽  
Total Mortality ◽  
Cattle Grazing ◽  
Tree Regeneration ◽  
Deciduous Tree ◽  
Populus Balsamifera ◽  
Haul Road ◽  
The Impact

The impact of summer cattle grazing on deciduous tree regeneration within uncut forests, clearcuts, partially harvested areas, and in-block haul road habitats was examined in four experimental pastures of central Alberta during 2008 and 2009. Sampling of 233 field plots, both inside and outside cattle exclosures, was used to document sapling densities, height, and type of damage. Tree densities (primarily aspen (Populus tremuloides Michx.)) differed among habitats but less so with exposure to cattle. Densities were greatest in clearcuts, followed by partially harvested areas and then uncut forest and haul roads. While exposure to cattle reduced total tree regeneration, sapling densities and sizes remained sufficient to meet postharvest standards for deciduous forest regeneration in Alberta, even with exposure to cattle. Cattle damage in harvested areas was primarily from browsing (≤3.2% of saplings), with proportionally more trees affected in uncut forests (8.6%). Browsing was particularly high on balsam poplar (Populus balsamifera L.) (25%) during 2008. Although sapling damage increased with high cattle stocking in 2008 (to 10.5%), total mortality was limited to 15.5% through 2009. These findings show that despite cattle impacts to some saplings, damage levels were insufficient to alter deciduous regeneration, highlighting the compatibility of cattle grazing and sustainable forest management on public lands in this region.

scholarly journals Evaluating the Performance of a Forest Succession Model to Predict the Long-Term Dynamics of Tree Species in Mixed Boreal Forests Using Historical Data in Northern Ontario, Canada

Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1181
Author(s):  
Guy R. Larocque ◽  
F. Wayne Bell
Keyword(s):  
Populus Tremuloides ◽  
Boreal Forests ◽  
Forest Ecosystems ◽  
Forest Succession ◽  
Regional Scale ◽  
Abies Balsamea ◽  
Forest Growth ◽  
Northern Ontario ◽  
Phase Dynamics

Environmental concerns and economic pressures on forest ecosystems have led to the development of sustainable forest management practices. As a consequence, forest managers must evaluate the long-term effects of their management decisions on potential forest successional pathways. As changes in forest ecosystems occur very slowly, simulation models are logical and efficient tools to predict the patterns of forest growth and succession. However, as models are an imperfect representation of reality, it is desirable to evaluate them with historical long-term forest data. Using remeasured tree and stand data from three data sets from two ecoregions in northern Ontario, the succession gap model ZELIG-CFS was evaluated for mixed boreal forests composed of black spruce (Picea mariana [Mill.] B.S.P.), balsam fir (Abies balsamea [L.] Mill.), jack pine (Pinus banksiana L.), white spruce (Picea glauca [Moench] Voss), trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.), northern white cedar (Thuja occidentalis L.), American larch (Larix laricina [Du Roi] K. Koch), and balsam poplar (Populus balsamefera L.). The comparison of observed and predicted basal areas and stand densities indicated that ZELIG-CFS predicted the dynamics of most species consistently for periods varying between 5 and 57 simulation years. The patterns of forest succession observed in this study support gap phase dynamics at the plot scale and shade-tolerance complementarity hypotheses at the regional scale.

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