Influence of Age and Growth Rate on Radial Anatomy of Annual Rings of Thuja occidentalis L. (Eastern White Cedar)

1993 ◽  
Vol 154 (3) ◽  
pp. 406-411 ◽  
Author(s):  
Christopher H. Briand ◽  
Usher Posluszny ◽  
Douglas W. Larson
Keyword(s):  
Growth Rate ◽  
Age And Growth ◽  
Annual Rings ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Eastern White Cedar

Evidence of high self-fertilization in natural populations of eastern white cedar (Thuja occidentalis)

1990 ◽  
Vol 68 (3) ◽  
pp. 663-668 ◽  
Author(s):  
Daniel J. Perry ◽  
Peggy Knowles
Keyword(s):  
Natural Populations ◽  
Outcrossing Rate ◽  
Significant Heterogeneity ◽  
Embryo Survival ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Northwestern Ontario ◽  
Outcrossing Rates ◽  
Self Fertilization ◽  
Eastern White Cedar

Arrays of open-pollinated seeds were assayed for allozyme polymorphisms at four loci (Mdh-1, Me, 6Pg-2, and Pgm) to obtain estimates of outcrossing rates for three eastern white cedar populations in northwestern Ontario, Canada. Multilocus population outcrossing rate estimates were low, ranging from 0.507 to 0.745, with significant heterogeneity among populations. Low stand densities and relatively high selfed embryo survival may have contributed to the low effective outcrossing rates observed. Single-tree multilocus outcrossing rate estimates were obtained for nine trees from one population. When estimated jointly with outcross pollen pool allele frequencies, these outcrossing rate estimates ranged from 0.253 to 1.023 with significant heterogeneity among trees. Key words: mating system, outcrossing rate, Thuja occidentalis L.

Patterns of Architectural Variation in Thuja occidentalis L. (Eastern White Cedar) from Upland and Lowland Sites

1991 ◽  
Vol 152 (4) ◽  
pp. 494-499 ◽  
Author(s):  
Christopher H. Briand ◽  
Usher Posluszny ◽  
Douglas W. Larson ◽  
Uta Matthes-Sears
Keyword(s):  
Thuja Occidentalis ◽  
White Cedar ◽  
Eastern White Cedar

Concentration of highway deicing agents along roadsides near London

1978 ◽  
Vol 56 (8) ◽  
pp. 1081-1085 ◽  
Author(s):  
A. C. Foster ◽  
M. A. Maun
Keyword(s):  
Filter Paper ◽  
Strong Correlation ◽  
Soil Samples ◽  
Freezing Rain ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
The Road ◽  
Eastern White Cedar ◽  
Snow Storms ◽  
Deicing Agents

Analysis of snow and soil samples showed that the concentrations of Na and Cl were higher near the road and decreased with increasing distance from the pavement. The level of calcium in soil did not change with distance. The concentration of calcium in the foliage of eastern white cedar trees (Thuja occidentalis L.) facing the highway was not significantly different from the concentration in the foliage on the opposite side. The filter paper discs attached to the foliage accumulated significantly high amounts of salts on days with freezing rain or snow storms. A strong correlation was found between element levels in the foliage and the levels found in filter paper discs.

Comparative seed morphology of Thuja occidentalis (eastern white cedar) from upland and lowland sites

1992 ◽  
Vol 70 (2) ◽  
pp. 434-438 ◽  
Author(s):  
Christopher H. Briand ◽  
Usher Posluszny ◽  
Douglas W. Larson
Keyword(s):  
Significant Variation ◽  
Morphological Characters ◽  
Seed Morphology ◽  
Right Wing ◽  
Habitat Types ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Character Variation ◽  
Eastern White Cedar ◽  
Individual Trees

As part of an investigation of the extent of habitat-specific variation in Thuja occidentalis L., cones were collected from cliff (dry upland) and swamp (wet lowland) sites in southern Ontario. The number of seeds per cone, number of fully developed seeds per cone, seed fresh weight, length, and width, length and width of embryo area, and length and width of right wing were determined. Seed yield on a per cone basis did not vary between habitat types or among sites within habitats. There was, however, significant variation among trees within sites. Individual seed characters did not vary between habitat types, but significant variation existed among sites within habitats, among trees within sites, and among cones within trees. Only the width of right wing failed to show cone to cone variation within individual trees. The majority of explainable variance for all characters could be apportioned to trees within sites. This and a relatively low degree of cone to cone variation suggest that the seed morphological characters were under strong maternal control. Differences among sites are thought to be the result of local environmental variation rather than genetic differences. The lack of habitat-specific seed character variation indicates that contrasting moisture regimes have little effect on quantitative seed morphology. No evidence exists for ecotypic variation with respect to seed morphology. Key words: Thuja occidentalis, eastern white cedar, seed morphology, ecotypes, cliff, swamp.

Decreased fire frequency and increased water levels affect riparian forest dynamics in southwestern boreal Quebec, Canada

2008 ◽  
Vol 38 (5) ◽  
pp. 1083-1094 ◽  
Author(s):  
Bernhard Denneler ◽  
Hugo Asselin ◽  
Yves Bergeron ◽  
Yves Bégin
Keyword(s):  
Riparian Forest ◽  
Fire Frequency ◽  
Water Levels ◽  
Ice Age ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Fraxinus Nigra ◽  
Eastern White Cedar ◽  
Black Ash ◽  
Forest Fringe

The relative importance of fire and flooding on the population dynamics of eastern white-cedar ( Thuja occidentalis L.) and black ash ( Fraxinus nigra Marsh.) was evaluated in eight old-growth riparian stands of southwestern boreal Quebec, Canada. Rising water levels and decreasing fire frequency since the end of the Little Ice Age (ca. 1850) were expected to have favoured an inland migration of the riparian forest fringe, with the flood-tolerant black ash colonizing the lower parts of the shore terraces and eastern white-cedar the upper parts. Black ash was found to be restricted to the riparian zone (<200 cm elevation), whereas eastern white-cedar trees did not occur below 100 cm above lake level. Gaps of postfire eastern white-cedar recruitment were noted in stands exposed to riparian disturbances, whereas relatively continuous recruitment occurred at protected sites. Black ash, more tolerant to flooding and ice push, invaded the shore terrace sites left vacant by eastern white-cedar. The riparian forest fringe surrounding Lake Duparquet is currently migrating upland and this trend is expected to continue as water levels continue to increase and fire frequency continues to decrease during the 21st century.

In vitro plantlet formation from embryonic explants of eastern white cedar (Thuja occidentalis L.)

1987 ◽  
Vol 3 (3) ◽  
pp. 273-283 ◽  
Author(s):  
I. S. Harry ◽  
M. R. Thompson ◽  
C.-Y. Lu ◽  
T. A. Thorpe
Keyword(s):  
Thuja Occidentalis ◽  
White Cedar ◽  
Plantlet Formation ◽  
Eastern White Cedar

Growth responses of riparian Thuja occidentalis to the damming of a large boreal lake

Botany ◽  
2008 ◽  
Vol 86 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Bernhard Denneler ◽  
Yves Bergeron ◽  
Yves Bégin ◽  
Hugo Asselin
Keyword(s):  
Water Level ◽  
Ring Width ◽  
High Water ◽  
Water Levels ◽  
Growth Responses ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Physiological Limit ◽  
Eastern White Cedar ◽  
Canadian Boreal Forest

Growth responses of riparian eastern white cedar trees ( Thuja occidentalis L.) to the double damming of a large lake in the southeastern Canadian boreal forest was analyzed to determine whether the shoreline tree limit is the result of physiological flood stress or mechanical disturbances. The first damming, in 1915, caused a rise in water level of ca. 1.2 m and resulted in the death of the trees that formed the ancient shoreline forest, as well as the wounding and tilting of the surviving trees (by wave action and ice push) that constitute the present forest margin. The second damming, in 1922, did not further affect the water level, but did retard the occurrence of spring high water levels, as well as reduce their magnitude. However, this did not injure or affect the mortality of riparian eastern white cedars. Radial growth was not affected by flooding stress, probably because inundation occurred prior to the start of the growing season (1915–1921) or was of too short duration to adversely affect tree metabolism (after 1921). It follows that (i) the shoreline limit of eastern white cedar is a mechanical rather than a physiological limit, and (ii) disturbance-related growth responses (e.g., ice scars, partial cambium dieback, and compression wood) are better parameters than ring width for the reconstruction of long-term water level increases of natural, unregulated lakes.

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