scholarly journals Vegetation of the Continental Northwest Territories at 6 ka BP

2007 ◽  
Vol 49 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Glen M. MacDonald
Keyword(s):  
Northwest Territories ◽  
Populus Tremuloides ◽  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Arctic Tundra ◽  
Range Limits ◽  
Mackenzie Delta ◽  
Delta Region ◽  
Low Arctic

ABSTRACTPollen records are used to reconstruct vegetation in the continental Northwest Territories at 6 ka (6000 14C yr BP). Picea glauca, P mariana, Larix laricina, Populus tremuloides, P. balsamifera, Alnus crispa and A. incana were present throughout their modern ranges in the Boreal and Subarctic Forest Zones by 6000 BP. Pinus banksiana, however, had not yet reached its present northern limits. Population densities of the dominant trees, Picea glauca and Picea mariana, were close to, or as high as, present. In the Mackenzie Delta region the range limit of Picea glauca was approximately 25 km north of its modern location just prior to 6000 BP. In contrast, the northern limits of the forest in central Canada were similar to present. The tundra vegetation close to the edge of the forest was similar to modern Low Arctic Tundra. Development of extensive Sphagnum peatlands had begun in the forested areas and the adjacent Low Arctic Tundra. Palaeoecological information regarding vegetation at 6000 BP remains lacking for the northeastern half of the study area. Therefore, the nature of the vegetation in much of the area now occupied by Low Arctic and Middle Arctic Tundra remains unknown. Important vegetation changes that occurred following 6 ka include : (1) the advance of Pinus banksiana to its present northern range limits, (2) the retreat of the northern range limits of Picea glauca in the Mackenzie Delta region between 6000 and 3500 BP and (3) the rapid and marked increase in the population density of Picea mariana in the treeline zone of the central Northwest Territories at 5000 BP followed by a decline at 4000 BP.

Classification and ordination of southern boreal forests from the Hondo – Slave Lake area of central Alberta

1992 ◽  
Vol 70 (3) ◽  
pp. 614-628 ◽  
Author(s):  
George H. La Roi
Keyword(s):  
Plant Species ◽  
Populus Tremuloides ◽  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Vascular Plant ◽  
Percent Cover ◽  
Lake Area ◽  
Vascular Plant Species ◽  
Community Types

Sixty-five undisturbed stands, spanning a wide range of physical habitats in the southern boreal subzone, were sampled in central Alberta using relevés, then classified with two-way indicator species analysis (TWINSPAN) and ordinated with detrended correspondence analysis (DECORANA), based on the estimated midsummer percent cover of 100 vascular plant species. Six floristically and ecologically distinct community types were recognized along soil-moisture and texture–nutrient gradients: oligotrophic PINUS BANKSIANA/ASTER LAEVIS on warm, xeromesic, nutrient-poor sand deposits; oligo-mesotrophic PINUS BANKSIANA/CORNUS CANADENSIS on cooler, xeromesic to submesic, low-nutrient sands; mesotrophic PICEA GLAUCA – POPULUS TREMULOIDES/ELYMUS INNOVATUS on mesic, medium-nutrient tills; eu-mesotrophic PICEA GLAUCA – POPULUS TREMULOIDES/RIBES TRISTE on mesic to hygromesic, nutrient-rich alluvium and till; oligotrophic PICEA MARIANA/RUBUS CHAMAEMORUS on cool, hygromesic to hygric, nutrient-poor peatlands; oligotrophic PICEA MARIANA/CAREX AQUATILIS on hygric to hydric, low-nutrient peatlands. The six community types and 19 species groups elucidated by TWINSPAN occupy distinct sectors on the two-dimensional DECORANA ordination that are associated with differences in moisture and nutrient availability. The community types are ecologically vicarious with boreal forest assemblages previously described for Alaska, central and eastern Canada, and northwestern Europe. Key words: cover, ecological series, gradient, moisture, nutrients, plant community, soil, vascular plant species, vegetation.

Forestry Operations in the Canadian Subarctic: an Ecological Argument Against Clear-cutting

1974 ◽  
Vol 1 (2) ◽  
pp. 87-92
Author(s):  
Don Gill
Keyword(s):  
Northwest Territories ◽  
Environmental Degradation ◽  
Picea Glauca ◽  
Secondary Succession ◽  
White Spruce ◽  
Arctic Tundra ◽  
Alnus Crispa ◽  
Clear Cutting ◽  
Low Arctic ◽  
Salix Spp

Environmental and floristic evidence is presented to show that, after removal of the White Spruce (Picea glauca) and willow-alder (Salix spp.–Alnus crispa) canopies from exposed sites within the boreal woodland of the Mackenzie River Delta, Northwest Territories, Canada, environmental degradation is such that secondary succession of low-arctic tundra heath, mosses, and lichens, takes place. The extreme exposure of cleared sites enables a hardy group of tundra plants to compete with the local flora and invade the previously forested location.

scholarly journals Assessing the Translucence and Color-Change Methods for Estimating Sapwood Depth in Three Boreal Species

Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 686 ◽  
Author(s):  
M. Quiñonez-Piñón ◽  
Caterina Valeo
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Wood Anatomy ◽  
Color Change ◽  
Microscopic Analysis ◽  
Forest Monitoring ◽  
Statistical Comparison ◽  
The Face ◽  
Species Specific

The translucence and color change in wood methods, which are commonly used to differentiate sapwood from heartwood in tree cores, are compared against the microscopic analysis of wood anatomy method for determining sapwood depth. The translucence method was tested on collected wood cores of White Spruce (Picea glauca (Moench) Voss) and Jack Pine (Pinus banksiana Lamb.). The color change in wood method was tested on Trembling Aspen (Populus tremuloides Michx.). For every statistical comparison, sapwood depth values obtained with the translucence or color-change methods were significantly different from those obtained using the microscopic analysis. Using the sapwood depth values obtained with microscopy as a reference, the bias associated with the translucence or color-change methods used on Picea glauca, Pinus banksiana and Populus tremuloides constantly under- or overestimated sapwood depths within −0.3 cm to 1.6 cm; −4.9 cm to 0.5 cm; and 0 to 1.8 cm, respectively. The different ranges of over- and underestimation arise from species-specific anatomical characteristics. Estimates for the errors in sapwood depth, when the depth is measured using either the translucence or color-change methods, are presented. These relationships and research outcomes will lead to more efficient forest monitoring and improved estimates of forest water balance, which in turn will lead to improved forest management in the face of climate change.

scholarly journals Taper Equations for Five Major Commercial Tree Species in Manitoba, Canada

2007 ◽  
Vol 22 (3) ◽  
pp. 163-170 ◽  
Author(s):  
Ryan J. Klos ◽  
G. Geoff Wang ◽  
Qing-Lai Dang ◽  
Ed W. East
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
White Spruce ◽  
Jack Pine ◽  
Volume Estimation ◽  
Trembling Aspen ◽  
Stem Form ◽  
Taper Equation ◽  
Taper Equations

Abstract Kozak's variable exponent taper equation was fitted for balsam poplar (Populus balsamifera L.), trembling aspen (Populus tremuloides Michx.), white spruce (Picea glauca [Moench] Voss), black spruce (Picea mariana [Mill.] B.S.P.), and jack pine (Pinus banksiana Lamb.) in Manitoba. Stem taper variability between two ecozones (i.e., Boreal Shield and Boreal Plains) were tested using the F-test. Regional differences were observed for trembling aspen, white spruce, and jack pine, and for those species, separate ecozone-specific taper equations were developed. However, the gross total volume estimates using the ecozone-specific equations were different from those of the provincial equations by only 2 percent. Although the regional difference in stem form was marginal within a province, a difference of approximately 7 percent of gross total volume estimation was found when our provincial taper equations were compared with those developed in Alberta and Saskatchewan. These results suggest that stem form variation increases with spatial scale and that a single taper equation for each species may be sufficient for each province.

The effect of pedogenetic processes on the distribution of phosphorus, calcium and magnesium in Gray Luvisols

1991 ◽  
Vol 71 (4) ◽  
pp. 397-410 ◽  
Author(s):  
X. J. Xiao ◽  
D. W. Anderson ◽  
J. R. Bettany
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Mineral Soil ◽  
Coniferous Forest ◽  
Soil Formation ◽  
Podzolic Soils ◽  
Exchangeable Ca ◽  
Phosphorus Losses

Pedogenesis and its effect on calcium (Ca), magnesium (Mg) and phosphorus (P) was studied on a sequence of seven Gray Luvisol soils in central Saskatchewan. The soils were formed on calcareous glacial till under trembling aspen (Populus tremuloides Michx), mixedwood (aspen and white spruce) (Picea glauca (Moench) Voss)) and coniferous (black spruce and jack pine) (Picea mariana (Mill) BSP and Pinus banksiana Lamb) forests. Soils under aspen had the highest concentration of total and exchangeable Ca and Mg in litter layers and Ae horizons, and had Ae and Bt horizons that were least acidic. The most acidic Ae and Bt horizons and lowest amounts of Ca and Mg occurred under coniferous forests, whereas the soils under mixedwood stands were intermediate. The thickness of eluvial (Ae and AB) horizons increased along the aspen to coniferous sequence. All soils had about 40% less P in their A and B horizons than was calculated to have been present at the start of soil formation. The greatest decrease in P was observed in the thickest and most acidic soil under coniferous forest. The present litter layers and vegetation make up only a small proportion of the P removed from the mineral soil. Unusually large amounts of P appear to have been translocated from A and B horizons during development of Gray Luvisols, in comparison to Chernozemic or even Podzolic soils. Our hypothesis proposes that P is ineffectively retained in the solum as P-clay-humus, or iron-P complexes and that organic P moves along with the soil water, laterally and downslope through permeable Ae horizon over less permeable Bt horizons, or vertically through macropores. Key words: Boreal forest, nutrient cycling, phosphorus losses, weathering, soil formation

Short-term effects of cut-to-length versus full-tree harvesting on conifer regeneration in jack pine, mixedwood, and black spruce forests in Manitoba

2004 ◽  
Vol 34 (9) ◽  
pp. 1938-1945 ◽  
Author(s):  
Isobel Waters ◽  
Steven W Kembel ◽  
Jean-François Gingras ◽  
Jennifer M Shay
Keyword(s):  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Jack Pine ◽  
Tree Regeneration ◽  
Understorey Vegetation ◽  
Advance Regeneration ◽  
The Impact

This study compares the effects of full-tree versus cut-to-length forest harvesting methods on tree regeneration in jack pine (Pinus banksiana Lamb.), mixedwood (Picea glauca (Moench) Voss – Populus tremuloides Michx. – Abies balsamea (L.) Mill.), and black spruce (Picea mariana (Mill.) BSP) sites in southeastern Manitoba, Canada. We surveyed tree regeneration densities, disturbance characteristics, and understorey vegetation in replicated control and harvested plots in each site type preharvest (1993) and 1 and 3 years postharvest (1994, 1996). In jack pine sites, the full-tree harvest method promoted regeneration of Pinus banksiana through increased disturbance of soil and the moss layer, and decreased slash deposition relative to the cut-to-length method. Conversely, in mixedwood sites the cut-to-length method resulted in less damage to advance regeneration and proved better at promoting postharvest regeneration of Abies balsamea and Picea glauca relative to the full-tree method. In black spruce sites, there were few differences in the impact of the two harvesting methods on regeneration of Picea mariana, which increased in frequency and density after both types of harvesting.

The influence of light quality and carbon dioxide enrichment on the growth and physiology of seedlings of three conifer species. I. Growth responses

1996 ◽  
Vol 74 (3) ◽  
pp. 383-390 ◽  
Author(s):  
John Hoddinott ◽  
Rickey Scott
Keyword(s):  
Growth Rates ◽  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Light Quality ◽  
Flux Ratio ◽  
Growth Period ◽  
Growth Responses ◽  
Relative Growth ◽  
Relative Growth Rates

Plant growth responds to light quality, as evaluated by the red/far-red (R/FR) quantum flux ratio, and to the level of CO2. Pinus banksiana, Picea mariana and Picea glauca seedlings were raised at 350, 700, or 1050 μL∙L−1 CO2 and high or low R/FR ratios and growth was measured over a 16-week growth period. Far-red rich light enhanced the whole plant and height relative growth rates of Pinus banksiana. The three species showed species specific responses in plant organ relative growth rates and partitioning ratios. On the basis of their biomass partitioning the species would be ranked Pinus banksiana < Picea mariana < Picea glauca for shade tolerance. In commercial operations, seedlings grown for outplanting are selected, in part, on the basis of plant form as described by the stem height/diameter ratio. More desirable ratios were obtained at ambient CO2 concentrations for Pinus banksiana and Picea mariana in red rich light and for Picea glauca in far-red rich light. Keywords: seedling growth, light quality, CO2 enrichment.

Coarse root biomass allometric equations for Abies balsamea, Picea mariana, Pinus banksiana, and Populus tremuloides in the boreal forest of Ontario, Canada

2011 ◽  
Vol 35 (10) ◽  
pp. 4189-4196 ◽  
Author(s):  
Brian W. Brassard ◽  
Han Y.H. Chen ◽  
Yves Bergeron ◽  
David Paré
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Picea Mariana ◽  
Root Biomass ◽  
Pinus Banksiana ◽  
Abies Balsamea ◽  
Allometric Equations ◽  
Coarse Root

Bottom-fast ice delineation with PolSAR and InSAR techniques in the Mackenzie Delta region, Northwest Territories, Canada

2013 ◽  
Vol 39 (4) ◽  
pp. 341-353 ◽  
Author(s):  
Bing Yue ◽  
Joseph Chamberland ◽  
John Mulvie
Keyword(s):  
Northwest Territories ◽  
Mackenzie Delta ◽  
Delta Region ◽  
Fast Ice
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