Seasonal changes in the major ash constituents of leaves and some woody components of trembling aspen and red osier dogwood

1978 ◽  
Vol 56 (15) ◽  
pp. 1798-1803 ◽  
Author(s):  
T. D. W. James ◽  
D. W. Smith
Keyword(s):  
Populus Tremuloides ◽  
Seasonal Changes ◽  
Growing Season ◽  
Early Spring ◽  
Reverse Direction ◽  
Trembling Aspen ◽  
Southern Ontario ◽  
Cornus Stolonifera ◽  
Nutrient Changes ◽  
Nutrient Variability

Concentrations of N, P, K, Ca, and Mg were determined at monthly intervals over the growing season in the leaves, twig bark, and twig wood of Populus tremuloides Michx. (trembling aspen) and in the leaves and stems of Cornus stolonifera Michx. (red osier dogwood) in southern Ontario. Concentrations of N, P, and K in the leaves of both species decreased from May to August. Levels of Mg and Ca increased. Nutrient changes in aspen twigs during the May to September period, with the exception of magnesium, followed the reverse direction to those in the leaves. Seasonal changes in all of the nutrients in twigs were very small. Seasonal nutrient variability in red osier stems was also slight, but concentrations of Mg and Ca showed a July peak, and K showed a peak in June. N and P declined from early spring to midsummer but by September in dogwood the levels had returned to the April values.

Seasonal changes in the caloric value of the leaves and twigs of Populus tremuloides

1978 ◽  
Vol 56 (15) ◽  
pp. 1804-1805 ◽  
Author(s):  
T. D. W. James ◽  
D. W. Smith
Keyword(s):  
Populus Tremuloides ◽  
Environmental Effects ◽  
Seasonal Changes ◽  
Dry Weight ◽  
Forest Tree ◽  
Trembling Aspen ◽  
Seasonal Fluctuations ◽  
Southern Ontario ◽  
Caloric Value ◽  
Second Peak

Seasonally averaged caloric values (kilocalories per gram dry weight) of Populus tremuloides Michx. (trembling aspen) in southern Ontario were 5.17 for leaves, 5.04 for twig bark, and 4.55 for twig wood. The marked difference between leaves and twig wood reflects the differing composition of these tissues. The caloric levels of all the aspen components were highest in May. Levels decreased markedly from May to June, increased to a second peak in August, and then declined again between August and September. The caloric value of twig bark and wood also showed a decline from September to November. Seasonal fluctuations in caloric value of trembling aspen leaves and twigs were large compared with changes reported for other forest tree species and it is suggested that aspen is relatively sensitive to environmental effects.

Wounding of aspen roots promotes suckering

2004 ◽  
Vol 82 (3) ◽  
pp. 310-315 ◽  
Author(s):  
Erin C Fraser ◽  
Victor J Lieffers ◽  
Simon M Landhäusser
Keyword(s):  
Populus Tremuloides ◽  
Growth Rates ◽  
Growing Season ◽  
Organic Layer ◽  
Trembling Aspen ◽  
Layer Depth ◽  
Injury Type ◽  
Organic Layers ◽  
Root Injury ◽  
Root Sucker

In early May, 1-m sections of trembling aspen (Populus tremuloides Michx.) roots in a forest cutblock were carefully exposed and examined for damage. Undamaged roots were subjected to one of three wounding treatments (scrape, sever, or uninjured control) and were then reburied to either the full normal organic layer depth or to one third of the normal depth. Following one growing season, the roots were reexposed and assessed for aspen sucker numbers and growth rates. Results indicate that injured roots produced suckers nearly twice as often as uninjured roots. Further, injured roots produced more suckers per root, and these suckers were taller and had greater leaf area. Roots buried under shallow organic layers also generated more suckers, regardless of injury type. The side of injury (distal or proximal) did not affect any of the measured variables. The present study suggests that moderate wounding of aspen roots increases initial sucker numbers and growth rates.Key words: trembling aspen, root sucker, root injury, regeneration.

Changes in the shrub and herb layers of vegetation after prescribed burning in Populus tremuloides woodland in southern Ontario

1978 ◽  
Vol 56 (15) ◽  
pp. 1792-1797 ◽  
Author(s):  
D. W. Smith ◽  
T. D. W. James
Keyword(s):  
Species Richness ◽  
Populus Tremuloides ◽  
Prescribed Burning ◽  
Canopy Cover ◽  
Abundant Species ◽  
Southern Ontario ◽  
Calamagrostis Canadensis ◽  
Cornus Stolonifera ◽  
Shrub Canopy ◽  
Microscale Heterogeneity

The undisturbed condition in the shrub and herb layers of a Populus tremuloides woodland in southern Ontario was characterized by a mosaic of two main vegetation groupings, one being relatively species rich and the other species poor. Their distribution was related chiefly to two environmental variables: (a) relative degree of shrub canopy cover, and (b) microtopographic position. Species-poor vegetation was associated with those sites having a closed shrub canopy and low, wet positions on the microtopographic gradient.Prescribed burning added a further dimension to the clumped pattern and species richness of the vegetation. Microscale heterogeneity created by the burns tended to increase species richness, but in general, richness was reduced by burning. Rapid postburn changes in the vegetation were largely restricted to shifts in dominance by the three most abundant species; Cornus stolonifera Michx., Calamagrostis canadensis (Michx.) Beauv., and Carex stricta var. strictior Lam. The changes in the dominants after burning appeared to be short lived but affected the overall structure of the shrub and herb vegetation.

Net nitrogen mineralization and nitrification in trembling aspen forest soils on the Boreal Plain

2003 ◽  
Vol 33 (11) ◽  
pp. 2262-2268 ◽  
Author(s):  
N Carmosini ◽  
K J Devito ◽  
E E Prepas
Keyword(s):  
Populus Tremuloides ◽  
N Mineralization ◽  
Growing Season ◽  
Large Contribution ◽  
Net N Mineralization ◽  
Trembling Aspen ◽  
Mineral Horizon ◽  
Net Nitrification ◽  
Winter Activity ◽  
Aspen Forest

In situ net N mineralization and net nitrification rates were measured in organic forest floor (LFH) and mineral horizons of mature and logged trembling aspen (Populus tremuloides Michx.) stands on the Boreal Plain in western Canada. Cumulative May to September mineralization for mature and logged plots was 1354 ± 534 and 1631 ± 1584 mg N·m–2, respectively, in the LFH horizon and 810 ± 394 and –305 ± 3957 mg N·m–2, respectively, in the mineral horizon. Net nitrification in mature and logged plots was 86 ± 142 and 658 ± 435 mg NO3-N·m–2, respectively, in the LFH horizon and 67 ± 50 and 409 ± 325 mg NO3-N·m–2, respectively, in the mineral horizon. Monthly mean NH4-N concentrations in the LFH tended to be higher in logged plots than in mature plots. Winter net N mineralization and nitrification rates in the LFH of mature plots were up to 7% and 11% of growing season net rates, respectively. In comparison, these rates in logged plots were up to 127% and 59% of the growing season net rates, respectively, indicating that winter activity may make a large contribution to annual net mineralization and nitrification after logging.

Weekly xylem production in trembling aspen (Populus tremuloides) in response to artificial defoliation

2004 ◽  
Vol 82 (5) ◽  
pp. 590-597 ◽  
Author(s):  
Brin Jones ◽  
Jacques Tardif ◽  
Richard Westwood
Keyword(s):  
Populus Tremuloides ◽  
Radial Growth ◽  
Regression Models ◽  
Wood Anatomy ◽  
Ring Width ◽  
Growing Season ◽  
Early Growth ◽  
Trembling Aspen ◽  
Forest Sites ◽  
Significant Difference

The present study investigated the effect of artificial defoliation on weekly radial xylem production in trembling aspen (Populus tremuloides Michx.). It was hypothesized that defoliated trees would show reduced xylem and vessel production and thinner secondary walls in fibres. Two adjacent natural forest sites were selected within Winnipeg, Manitoba. Microcores were extracted weekly from the stems of 30 aspen trees from May to October 2002. Ten aspen trees were defoliated using pole pruners between 22 June and 6 July. Measurements included weekly xylem increment, annual vessel characteristics, and late growing season fibre dimensions. No significant difference in overall ring width was observed; however, trees from both groups showed a significant reduction in ring width in 2002. The ratio of radial growth in 2002 / radial growth in 2001 was significantly less in defoliated trees, suggesting a higher reduction in radial growth due to defoliation. Sigmoidal regression models suggested early growth cessation in defoliated trees. No significant differences in vessel characteristics were observed between groups; however, the diameter and lumen width of fibres was significantly reduced in defoliated trees. It is speculated that a shorter radial growing season may have led to a reduced cell elongation period. An early cessation of the radial growing season associated with a reallocation of carbohydrates to produce a second flush of leaves could explain the reduced size of fibres from defoliated trees.Key words: wood anatomy, diffuse porous, image analysis, radial growth, cell dimension, dendrochronology.

Impact of simulated aspen shoot blight on trembling aspen

2007 ◽  
Vol 37 (4) ◽  
pp. 719-725 ◽  
Author(s):  
P.V. Blenis
Keyword(s):  
Populus Tremuloides ◽  
Tree Height ◽  
Growing Season ◽  
Common Disease ◽  
Trembling Aspen ◽  
Mechanical Wounding ◽  
Tree Form ◽  
Shoot Blight ◽  
The Difference ◽  
Intensively Managed

Although aspen shoot blight (ASB), caused by Pollaccia americana Ondrej, is a common disease of trembling aspen ( Populus tremuloides Michx.), its impact is uncertain. Mechanical wounding, previously shown to be a reliable surrogate for ASB infection, was used to assess ASB impact in two experiments. In the first experiment, the effect of date of wounding on impact was studied by wounding 1-year-old aspen on four dates between 29 June and 10 August 2001. Tree form at the end of the 2001 growing season varied with wounding date, and for each of the wounding dates, tree height was reduced relative to that of unwounded, control trees. After the 2005 growing season, only trees wounded on 17 July were shorter than unwounded trees and the difference in heights was only 62 cm. In the second experiment, trees spaced at 2.0 or 0.67 m were wounded in four successive seasons to determine the effect of multiple years of infection on trees growing at different densities. Simulated ASB reduced tree height by an average of 16 cm, whereas branchiness was not increased by ASB, even at the lower density. Although ASB should not be ignored, these results suggest that it is unlikely to be amongst the most destructive pests of intensively managed aspen.

scholarly journals 134 Seasonal Variation in Composition and Total Load of Leaf Blade Epicuticular Waxes on Hosta

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 412D-412
Author(s):  
Jessie Keith ◽  
Carole H. Gaston ◽  
Matthew A. Jenks
Keyword(s):  
Seasonal Variation ◽  
Seasonal Changes ◽  
Leaf Blade ◽  
Growing Season ◽  
Early Spring ◽  
Gas Chromatography Mass Spectrometry ◽  
Epicuticular Waxes ◽  
Primary Alcohols ◽  
Total Load ◽  
Detailed Chemical

Hosta variants for epicuticular waxes were selected based on variation in surface glaucousness, from highly glaucous to highly glossy. In an effort to determine seasonal variation in hosta waxes, gas-chromatography mass-spectrometry was used to perform detailed chemical analysis of the adaxial and abaxial leaf blade waxes four times points during the growing season, early spring, mid-spring, mid-summer, and autumn. These studies revealed that in all variants, the total wax loads increased dramatically during the period of leaf expansion in the spring, dropped roughly five fold by midsummer, and then accumulated slightly above summer levels into the fall season. The dominant wax constituent class on all hosta cultivars was primary alcohols. Changes in these alcohols were primarily responsible for seasonal changes in total wax load. In some variants, the shorter chain length alcohols were unusually high compared with alcohol distributions normally found on other plants. Besides primary alcohols, significant amounts of acids, aldehydes, and alkanes, were also found and shown to vary during the growing season. A possible association between these seasonal changes in wax profiles and hosta resistance to slugs is discussed.

Photosynthesis of black spruce, jack pine, and trembling aspen after artificially induced frost during the growing season

1998 ◽  
Vol 28 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Manuel Lamontagne ◽  
Hank Margolis ◽  
Francine Bigras
Keyword(s):  
Populus Tremuloides ◽  
Picea Mariana ◽  
Tree Species ◽  
Pinus Banksiana ◽  
Black Spruce ◽  
Recovery Period ◽  
Growing Season ◽  
Jack Pine ◽  
Trembling Aspen ◽  
Monitoring Period

Light-saturated photosynthesis following artificial frosts was monitored for black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), and trembling aspen (Populus tremuloides Michx.). None of the species exposed to -9°C in May or to -6 and -9°C in August recovered within the 23- and 14-day monitoring periods, respectively. Black spruce and jack pine treated at -6°C in May recovered within 5 and 23 days, respectively. Black spruce treated at -3°C in August recovered within 10 days. Frosts were applied to the upper and lower canopies of mature black spruce and jack pine in June and to mature trembling aspen in July. For black spruce, the lower canopy did not recover whereas the upper canopy partially recovered over the 10-day monitoring period. For jack pine and trembling aspen, there were no differences in recovery between canopy levels. Jack pine treated at -5.5°C recovered within the 10-day monitoring period whereas at -8.5°C, it only partially recovered. Although recovery period varied with species, phenological state, and frost temperature, gradual recovery of photosynthesis over 5-21 days seems a reasonable modelling algorithm for boreal tree species when growing season frosts lower than -3°C occur. However, cooling rates in our experiments were greater than those that normally occur in nature.

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