Snow damage to boreal mixedwood stands in northern Alberta

1974 ◽  
Vol 50 (2) ◽  
pp. 70-73 ◽  
Author(s):  
Don Gill
Keyword(s):  
Snow Damage ◽  
Northern Alberta ◽  
Mixedwood Stands

not available

scholarly journals Influence of stand size on pattern of live trees in mixedwood landscapes following wildfire

2005 ◽  
Vol 81 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Cheryl Smyth ◽  
Jim Schieck ◽  
Stan Boutin ◽  
Shawn Wasel
Keyword(s):  
Key Words ◽  
Ecosystem Management ◽  
Natural Disturbance ◽  
Aerial Photographs ◽  
Large Fire ◽  
Forest Harvest ◽  
Burned Areas ◽  
Live Tree ◽  
Northern Alberta ◽  
Mixedwood Stands

Burned areas and patches of residual live trees were mapped from post-fire aerial photographs of 168 mixedwood stands (a total of 9367 ha), in eight large wildfires in the boreal forest of northern Alberta. The stands were stratified into three size classes: small (<10 ha), medium (10–60 ha), and large (>60 ha).We described the area occupied by single live residual trees, unburned patches of live trees and partially burned patches of live trees within these mixedwood stands. Although results from individual stands were highly variable, there was proportionally more area covered by live residual trees in large fire-killed stands compared to medium stands, which in turn had proportionally more than small stands. For most sizes and types of live tree patches, larger fire-killed stands had a greater proportion of live tree area compared to smaller stands. Results of this study are compared to similar studies and current harvest guidelines. We outline the amount and distribution of live tree patches that would be needed to create harvest areas similar to that found after wildfire. Key words: natural disturbance, wildfire, live residual trees, ecosystem management, forest harvest pattern, boreal mixedwood

scholarly journals Rubella Immunity among Pregnant Women in a Canadian Provincial Screening Program

2009 ◽  
Vol 20 (3) ◽  
pp. 73-77 ◽  
Author(s):  
Mark J Kearns ◽  
Sabrina S Plitt ◽  
Bonita E Lee ◽  
Joan L Robinson
Keyword(s):  
Public Health ◽  
Screening Program ◽  
Study Data ◽  
Test Results ◽  
Childbearing Age ◽  
Younger Women ◽  
The Public ◽  
Health Significance ◽  
Health Database ◽  
Northern Alberta

BACKGROUND: There are limited recent data on rubella immunity in women of childbearing age in Canada. In the present paper, the proportion of rubella seroreactivity and redundant testing (testing of women previously seropositive when tested by the same physician) in the Alberta prenatal rubella screening program were studied.METHODS: In the present retrospective observational study, data on all specimens submitted for prenatal screening in Alberta between August 2002 and December 2005 were extracted from the Provincial Laboratory for Public Health database. The proportion of rubella screening and immunoglobulin G (IgG) seroreactivity were determined. Demographic variables were compared between rubella seroreactors and nonseroreactors. The proportion of redundant testing was determined.RESULTS: Of 159,046 prenatal specimens, 88.3% (n=140,473) were screened for rubella immunity. In total, 8.8% of specimens tested negative for rubella IgG. Younger women (23.2% of women younger than 20 years of age versus 4.7% of women between 35 and 39 years of age; P<0.001) and women from northern Alberta (11.9% versus 8.1% [overall]; P<0.001) were significantly more likely to have seronegative specimens. Of the 20,044 women who had multiple rubella immunity screenings, 88.1% (n=17,651) had multiple positive test results. In total, 20.7% of the 42,274 specimens submitted from women with multiple screenings were deemed redundant.DISCUSSION: Younger women were most likely to be seronegative for rubella. The public health significance of women entering their childbearing years with low or undetectable rubella IgG levels remains to be determined. A large number of women with documented rubella immunity were unnecessarily retested.

VARIATION AMONG BRITISH COLUMBIA AND NORTHERN ALBERTA POPULATIONS OF RASPBERRIES, RUBUS IDAEUS SUBSPP. STRIGOSUS MICHX.

1972 ◽  
Vol 52 (6) ◽  
pp. 1067-1072 ◽  
Author(s):  
M. C. J. VAN ADRICHEM
Keyword(s):  
British Columbia ◽  
Seed Weight ◽  
Fruit Weight ◽  
Winter Hardiness ◽  
Rubus Idaeus ◽  
Specific Character ◽  
Positive Correlation ◽  
Total Seed ◽  
Northern Alberta ◽  
Number Of Seeds

Several population samples of Rubus idaeus subspp. strigosus Michx. (raspberries) were collected in British Columbia and northern Alberta and a number of characters were studied and compared with the cultivar Trent. Significant differences between populations were found for cane length, number of buds per cane, percentage of buds growing, number of inflorescences and flowers per bud, fruit and seed weight. There was a positive correlation between the total seed weight and the number of seeds, and between the total seed and fruit weight. No distinct types could be established based on location or elevation. None of the populations showed significantly better winter hardiness than the cultivar Trent, and although some had a specific character that was superior, none was found to have overall superiority.

scholarly journals Precommercial Thinning Increases Spruce Yields in Boreal Mixedwoods in Alberta, Canada

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 412
Author(s):  
Ivan Bjelanovic ◽  
Phil Comeau ◽  
Sharon Meredith ◽  
Brian Roth
Keyword(s):  
Growth Models ◽  
Growth And Yield ◽  
Diameter Growth ◽  
Growth Responses ◽  
Projection System ◽  
Precommercial Thinning ◽  
Thinning Intensity ◽  
Boreal Mixedwoods ◽  
Using Data ◽  
Mixedwood Stands

A few studies in young mixedwood stands demonstrate that precommercial thinning of aspen at early ages can improve the growth of spruce and increase stand resilience to drought. However, information on tree and stand responses to thinning in older mixedwood stands is lacking. To address this need, a study was initiated in 2008 in Alberta, Canada in 14 boreal mixedwood stands (seven each at ages 17 and 22). This study investigated growth responses following thinning of aspen to five densities (0, 1000, 2500, 5000 stems ha−1 and unthinned (control)). Measurements were collected in the year of establishment, and three and eight years later. Mortality of aspen in the unthinned plots was greater than in the thinned plots which were not significantly different amongst each other. Eight years following treatment, aspen diameter was positively influenced by thinning, while there was no effect on aspen height. The density of aspen had no significant effect on the survival of planted spruce. Spruce height and diameter growth increased with both aspen thinning intensity and time since treatment. Differentiation among treatments in spruce diameter growth was evident three years from treatment, while differentiation in height was not significant until eight years following treatment. Yield projections using two growth models (Mixedwood Growth Model (MGM) and Growth and Yield Projection System (GYPSY)) were initialized using data from the year eight re-measurements. Results indicate that heavy precommercial aspen thinning (to ~1000 aspen crop trees ha−1) can result in an increase in conifer merchantable volume without reducing aspen volume at the time of harvest. However, light to moderate thinning (to ~2500 aspen stems ha−1 or higher), is unlikely to result in gains in either deciduous or conifer merchantable harvest volume over those of unthinned stands.

scholarly journals Telephone consultations with otolaryngology – head and neck surgery reduced emergency visits and specialty consultations in northern Alberta

2020 ◽  
Vol 49 (1) ◽  
Author(s):  
Peter George Jaminal Tian ◽  
Dean Eurich ◽  
Hadi Seikaly ◽  
Douglas Boisvert ◽  
John Montpetit ◽  
...  
Keyword(s):  
Head And Neck ◽  
Neck Surgery ◽  
Head And Neck Surgery ◽  
Emergency Visits ◽  
Northern Alberta
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