Effects of aspen (Populus tremuloides) sucker removal on postfire conifer regeneration in central Alaska

2005 ◽  
Vol 35 (2) ◽  
pp. 483-486 ◽  
Author(s):  
Jill F Johnstone
Keyword(s):  
Seed Germination ◽  
Populus Tremuloides ◽  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Negative Response ◽  
Treatment Results ◽  
Conifer Species ◽  
Canopy Development

This experiment tests the effects of early canopy development by asexually regenerating aspen (Populus tremuloides Michx.) on conifer recruitment after fire in central Alaska. The establishment and growth of three conifer species were observed in response to aboveground removal of aspen suckers for three seasons after burning by wildfire. Of the three species, Pinus contorta Dougl. ex Loud. had the most widespread seed germination and showed the strongest negative response to the presence of the aspen canopy. Picea mariana (Mill.) BSP and Picea glauca (Moench) Voss had low germination and weak or neutral responses to aspen removal. Seedlings of all species accumulated more biomass in the removal treatment. Results from the experiment suggest that competition by aspen early after disturbance can significantly reduce conifer recruitment and growth, an effect that may reinforce the long-term dominance of aspen in asexually regenerating stands.

The Douglas-fir forests of Banff and Jasper National Parks, Canada

1970 ◽  
Vol 48 (10) ◽  
pp. 1703-1726 ◽  
Author(s):  
Paul W. Stringer ◽  
George H. La Roi
Keyword(s):  
National Parks ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Vegetation Change ◽  
Floristic Composition ◽  
Stand Age ◽  
Physical Habitat ◽  
Regression Equations ◽  
Habitat Differences

Twenty stands of uniform, mature, undisturbed Pseudotsuga menziesii var. glauca forest were selected in Banff and Jasper National Parks, using a combination of airphoto and ground surveys. Quantitative sampling methods were used to describe their floristic composition, vegetation structure, and physical habitats.Scattered trees of Pinus contorta, Picea glauca, and Populus tremuloides occurred in the Pseudotsuga forests. The poorly developed shrub strata contained Shepherdia canadensis, Rosa acicularis, Spiraea lucida, Juniperus communis. Major herb, dwarf shrub, bryophyte, and lichen species were Elymus innovatus, Calamagrostis rubescens, Fragaria virginiana, Astragalus decumbens, Aster conspicuus; Arctostaphylos uva-ursi, Linnaea borealis; Hylocomium splendens, Abietinella abietina, Tortula ruralis; Peltigera canina. A cyclical pattern of vegetation change is related to the death, replacement, and maturation of Pseudotsuga trees.Relations between vegetation and physical habitat were analyzed by simple correlation and multiple regression. Available potassium in soil, stand age, and slope exposure were most influential in regression equations for tree stratum development. Understory strata were primarily correlated with tree stratum development.A two-dimensional stand ordination based on the vegetational similarity of subordinate vascular strata showed a pronounced separation of Banff and Jasper Pseudotsuga forests, and prompted recognition of two new climax associations (sensu Daubenmire): Pseudotsuga / Elymus innovatus in Jasper; Pseudotsuga / Calamagrostis rubescens – Elymus innovatus in Banff. Habitat differences between the two associations include macroclimate, parent materials, and soil moisture.

Decadal observations of tree regeneration following fire in boreal forests

2004 ◽  
Vol 34 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Jill F Johnstone ◽  
F S Chapin III ◽  
J Foote ◽  
S Kemmett ◽  
K Price ◽  
...  
Keyword(s):  
British Columbia ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
Boreal Forests ◽  
Pinus Contorta ◽  
Stand Structure ◽  
Stand Density ◽  
Tree Regeneration ◽  
Direct Observations ◽  
Highly Correlated

This paper presents data on early postfire tree regeneration. The data were obtained from repeated observations of recently burned forest stands along the Yukon – British Columbia border and in interior Alaska. Postfire measurements of tree density were made periodically for 20–30 years, providing direct observations of early establishment patterns in boreal forest. Recruitment rates of the dominant tree species in both study areas were highest in the first 5 years after fire, and additional net establishment was not observed after 10 years. The postfire population of spruce (Picea mariana (Mill.) BSP and Picea glauca (Moench) Voss s.l.) remained constant after the first decade in the two study areas. Populations of aspen (Populus tremuloides Michx.) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) both declined after 10 years in mixed-species stands along the Yukon – British Columbia border. Mortality rates of aspen and pine were positively correlated with their initial densities, indicating that thinning occurred as a density-dependent process. At all sites, measurements of stand density and composition made early were highly correlated with those made late in the monitoring period, indicating that patterns of stand structure initiated within a few years after fire are maintained through subsequent decades of stand development.

Fungi that cause sapstain in Canadian softwoods

1999 ◽  
Vol 45 (11) ◽  
pp. 914-922 ◽  
Author(s):  
A Uzunovic ◽  
D -Q Yang ◽  
P Gagné ◽  
C Breuil ◽  
L Bernier ◽  
...  
Keyword(s):  
Picea Mariana ◽  
Picea Glauca ◽  
Pinus Banksiana ◽  
Pinus Contorta ◽  
Abies Balsamea ◽  
Forest Products ◽  
Fungal Species ◽  
Forest Products Industry ◽  
Diverse Range ◽  
Commercially Important

The Canadian forest products industry suffers considerable losses due to discoloration caused by sapstain fungi. Although studied for a number of years, the identity, biology, and ecology of these fungi are still only partly understood. To determine which fungi caused stain problems, a detailed survey was conducted at seven selected sawmills across Canada. In summer 1997, fresh logs and lumber were set aside in the mills 1 month prior to sampling for fungi. We excluded bark-beetle-attacked wood and our logs remained free from their attack during storage. Five commercially important softwood species, Abies balsamea (L.) Mill., Picea mariana (Mill.) B.S.P., Picea glauca (Moench) Voss, Pinus contorta Dougl., and Pinus banksiana Lamb., were included in the studies. A total of 1863 isolates were isolated from stained and adjacent areas on test wood, and were identified based on their morphological and physiological characteristics and mating compatibility to 13 different species representing five genera. The most commonly encountered genus, Ophiostoma (97%), was represented by nine species. A more diverse range of fungi was found in logs than in lumber; some species were more frequently isolated from one type of substrate and rarely (or not at all) from the other. No fungal species occurred exclusively in a particular region or wood substrate.Key words: bluestain, lumber, logs, Ophiostoma, Ceratocystis.

scholarly journals Regeneration of aspen following partial and strip understory protection harvest in boreal mixedwood forests

2009 ◽  
Vol 85 (4) ◽  
pp. 631-638 ◽  
Author(s):  
Alison D Lennie ◽  
Simon M Landhäusser ◽  
Victor J Lieffers ◽  
Derek Sidders
Keyword(s):  
Forest Management ◽  
Key Words ◽  
Populus Tremuloides ◽  
Picea Glauca ◽  
Basal Area ◽  
White Spruce ◽  
Mixedwood Forests ◽  
Partial Harvest ◽  
Second Year

Trembling aspen regeneration was studied in 2 types of partial harvest systems designed to harvest mature aspen but protect immature spruce and encourage natural aspen regeneration. Two partial harvest systems, where the residual aspen was either left in strips or was dispersed uniformly, were compared to traditional clearcuts. After the first and second year since harvest, aspen sucker density and growth was similar between the 2 partial harvests, but was much lower than in the clearcuts. However, in the partial cuts the regeneration density was very much dependent on the location relative to residual trees. The density of regeneration was inversely related to the basal area of residual aspen; however, sucker height was inversely related to the basal area of the residual spruce. Although there were adequate numbers of suckers after partial harvest, their viability and contribution to the long-term productivity of these mixedwood stands is not clear. Key words: silvicultural systems, forest management, residual canopy, white spruce, Populus tremuloides, Picea glauca, traffic

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.

scholarly journals Tree Growth Response Along Seismic Lines in Alberta

1986 ◽  
Vol 62 (1) ◽  
pp. 29-34 ◽  
Author(s):  
I. E. Bella
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Forest Cover ◽  
Black Spruce ◽  
Rocky Mountain ◽  
Radial Increment ◽  
Growth Data ◽  
Breast Height ◽  
Seismic Lines

Stem growth data from breast height were collected from about 2000 trees on 192 sample transects (plots) located adjacent to seismic lines. Sampled stands represented the most important forest cover types between 10 and 100 years of age over a range of site conditions in the foothills of western Albetra from Rocky Mountain House to Grande Prairie. Line clearing stimulated breast height radial increment fairly consistently in the 20% range of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) B.S.P.) trees. This improvement expressed in terms of stand growth, however, fell far short of that required to make up for the loss of wood production over these lines if the cut trees are not utilized. The lack of significant stimulation from line clearing in aspen (Populus tremuloides Michx.) stands indicates a complete loss of production due to the lines.

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.

A biophysical process model of tree mortality in surface fires

2008 ◽  
Vol 38 (7) ◽  
pp. 2013-2029 ◽  
Author(s):  
S. T. Michaletz ◽  
E. A. Johnson
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Process Model ◽  
Tree Mortality ◽  
Mortality Data ◽  
Sapwood Area ◽  
First Order ◽  
Surface Fires ◽  
Engelmann Spruce

The mechanisms governing tree mortality in surface fires are poorly understood, owing in large part to the absence of a process-based framework for defining and evaluating these mechanisms. This paper begins the development of such a framework by deriving a first-order process model of tree mortality in surface fires (intensities less than approximately 2500 kW·m–1). A buoyant line-source plume model is used to drive heat transfer models of vascular cambium and vegetative bud necroses, which are linked to tree mortality using an allometrically-based sapwood area budget. Model predictions are illustrated for white spruce ( Picea glauca ), lodgepole pine ( Pinus contorta ), and trembling aspen ( Populus tremuloides ) and are compared with independent mortality data for Engelmann spruce ( Picea engelmannii Parry ex Engelm.) and Pinus contorta Dougl. Results help define first-order mortality mechanisms and suggest second-order mortality mechanisms that should be incorporated into future modeling efforts.

A comparison of ectomycorrhiza communities from three conifer species planted on forest gap edges

1999 ◽  
Vol 77 (8) ◽  
pp. 1193-1198 ◽  
Author(s):  
J M Kranabetter ◽  
S Hayden ◽  
E F Wright
Keyword(s):  
Tree Species ◽  
Picea Glauca ◽  
Pinus Contorta ◽  
Abies Lasiocarpa ◽  
Community Similarity ◽  
Conifer Species ◽  
Host Preferences ◽  
The North ◽  
Wide Range ◽  
Species Comparisons

We examined the ectomycorrhiza communities on lodgepole pine (Pinus contorta var. latifolia Engelm), white spruce (Picea glauca (Moench) Voss), and subalpine fir (Abies lasiocarpa (Hook.) Nutt) seedlings planted together on mature-forest edges in northwestern British Columbia. We examined 32 seedlings of each tree species, grouped by pairs along the north and south edges of eight gaps. We found 74 morphotypes in total, with an average of 52 morphotypes per tree species. Morphotypes with emanating hyphae or strands made up 60% of the overall ectomycorrhiza community. Multihost fungi averaged almost 60% of total morphotypes in species comparisons, although some of the multihost fungi appeared to have tree host preferences. The average community similarity, based on morphotype abundance, was 52% between conifer species, and 37% for morphotypes with emanating hyphae or strands. Within planted groups, between seedlings 1-2 m apart, community similarity ranged from 2 to 40% for morphotypes with emanating hyphae or strands. In mature, mixed forests, the infrequent occurrence of many multihost ectomycorrhizae created a wide range in the probability of hyphal linkages between neighboring seedlings.Key words: ectomycorrhizae, community similarity, multiple host, host specificity, Pinus contorta, Picea glauca, Abies lasiocarpa

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