Growth and chemical responses of trembling aspen to simulated browsing and ungulate saliva

Abstract In urban centres, leaves are customarily gathered and temporarily stored in large roadside piles prior to their transport to disposal sites. To simulate the release of total phosphorus to urban runoff, birch and trembling aspen leaves were leached with distilled water in laboratory flasks. There was no difference in rate of total phosphorus release between oven-dried and non-dried leaves. An empirical equation developed from these data and knowledge of the litterfall rates for southern Canada indicated that leaves yielded from 11 to 45 mg TP m−2 of forested watershed. This amount represents up to 5% of the total export of total phosphorus from urban catchments and has the potential to exacerbate eutrophication of municipal waters if leaf pickup is not promptly enforced.

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Ethylene enhances root water transport and aquaporin expression in trembling aspen (Populus tremuloides) exposed to root hypoxia

BMC Plant Biology ◽

10.1186/s12870-021-02995-7 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Xiangfeng Tan ◽

Mengmeng Liu ◽

Ning Du ◽

Janusz J. Zwiazek

Keyword(s):

Gas Exchange ◽

Water Transport ◽

Populus Tremuloides ◽

Leaf Gas Exchange ◽

Hydraulic Conductance ◽

Root Hydraulic Conductance ◽

Trembling Aspen ◽

Expression Levels ◽

Root Hypoxia ◽

Exogenous Ethylene

Abstract Background Root hypoxia has detrimental effects on physiological processes and growth in most plants. The effects of hypoxia can be partly alleviated by ethylene. However, the tolerance mechanisms contributing to the ethylene-mediated hypoxia tolerance in plants remain poorly understood. Results In this study, we examined the effects of root hypoxia and exogenous ethylene treatments on leaf gas exchange, root hydraulic conductance, and the expression levels of several aquaporins of the plasma membrane intrinsic protein group (PIP) in trembling aspen (Populus tremuloides) seedlings. Ethylene enhanced net photosynthetic rates, transpiration rates, and root hydraulic conductance in hypoxic plants. Of the two subgroups of PIPs (PIP1 and PIP2), the protein abundance of PIP2s and the transcript abundance of PIP2;4 and PIP2;5 were higher in ethylene-treated trembling aspen roots compared with non-treated roots under hypoxia. The increases in the expression levels of these aquaporins could potentially facilitate root water transport. The enhanced root water transport by ethylene was likely responsible for the increase in leaf gas exchange of the hypoxic plants. Conclusions Exogenous ethylene enhanced root water transport and the expression levels of PIP2;4 and PIP2;5 in hypoxic roots of trembling aspen. The results suggest that ethylene facilitates the aquaporin-mediated water transport in plants exposed to root hypoxia.

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The bacteria in sapwood, wetwood, and heartwood of trembling aspen (Populus tremuloides)

Canadian Journal of Botany ◽

10.1139/b73-060 ◽

1973 ◽

Vol 51 (2) ◽

pp. 498-500 ◽

Cited By ~ 15

Author(s):

Donald M. Knutson

Keyword(s):

Populus Tremuloides ◽

Trembling Aspen ◽

Indigenous Bacteria ◽

Large Populations ◽

Xylem Tissue

Bacteria (Erwinia, Bacillus) were consistently isolated from all samples of aspen sapwood and heartwood. In wetwood zones (water-soaked xylem tissue) or discolored heartwood, large populations often occur. No organisms unique to wetwood were isolated. Wetwood probably is formed by nonmicrobial means and, once formed, merely supports large populations of indigenous bacteria.

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The influence of competition from herbaceous vegetation and shade on simulated browsing tolerance of coniferous and deciduous saplings

Oikos ◽

10.1111/j.2007.0030-1299.16264.x ◽

2007 ◽

Vol 117 (3) ◽

pp. 415-423 ◽

Cited By ~ 28

Author(s):

Charlotte Vandenberghe ◽

François Freléchoux ◽

Alexandre Buttler

Keyword(s):

Herbaceous Vegetation ◽

Simulated Browsing

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Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

International Journal of Forestry Research ◽

10.1155/2012/573640 ◽

2012 ◽

Vol 2012 ◽

pp. 1-12

Author(s):

Teresa A. Newsome ◽

Jean L. Heineman ◽

Amanda F. Linnell Nemec

Keyword(s):

British Columbia ◽

Lodgepole Pine ◽

Geographic Range ◽

Regression Analyses ◽

Relative Height ◽

Trembling Aspen ◽

Ecosystem Productivity ◽

Height Ratio ◽

Critical Height ◽

South Central

Critical height ratios for predicting competition between trembling aspen and lodgepole pine were identified in six juvenile stands in three south-central British Columbia ecosystems. We used a series of regression analyses predicting pine stem diameter from the density of neighbouring aspen in successively shorter relative height classes to identify the aspen-pine height ratio that maximizedR2. Critical height ratios varied widely among sites when stands were 8–12 years old but, by age 14–19, had converged at 1.25–1.5. MaximumR2values at age 14–19 ranged from 13.4% to 69.8%, demonstrating that the importance of aspen competition varied widely across a relatively small geographic range. Logistic regression also indicated that the risk of poor pine vigour in the presence of aspen varied between sites. Generally, the degree of competition, risk to pine vigour, and size of individual aspen contributing to the models declined along a gradient of decreasing ecosystem productivity.

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Wounding of aspen roots promotes suckering

Canadian Journal of Botany ◽

10.1139/b04-009 ◽

2004 ◽

Vol 82 (3) ◽

pp. 310-315 ◽

Cited By ~ 25

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.

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Species specific growth responses of black spruce and trembling aspen may enhance resilience of boreal forest to climate change

Journal of Ecology ◽

10.1111/1365-2745.12007 ◽

2012 ◽

Vol 101 (1) ◽

pp. 231-242 ◽

Cited By ~ 47

Author(s):

Igor Drobyshev ◽

Sylvie Gewehr ◽

Frank Berninger ◽

Yves Bergeron

Keyword(s):

Climate Change ◽

Boreal Forest ◽

Specific Growth ◽

Black Spruce ◽

Trembling Aspen ◽

Growth Responses ◽

Species Specific

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THE BEHAVIOUR OF FIVE WOOD SPECIES IN COMPRESSION

IAWA Journal ◽

10.1163/22941932-90000298 ◽

2002 ◽

Vol 23 (2) ◽

pp. 201-211 ◽

Cited By ~ 11

Author(s):

Simon Ellis ◽

Paul Steiner

Keyword(s):

Young’S Modulus ◽

Populus Tremuloides ◽

Wood Species ◽

Young's Modulus ◽

Douglas Fir ◽

Thuja Plicata ◽

Trembling Aspen ◽

Moisture Contents ◽

Red Cedar ◽

Western Red Cedar

Five wood species, Oregon ash (Fraxinus latifolia Benth.), Balau (Shorea spp.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Western red cedar (Thuja plicata Donn ex D. Don), and Trembling aspen (Populus tremuloides Michx.) were loaded in compression longitudinally, radially and tangentially. The wood cubes were conditioned to one of four moisture contents prior to loading. Small cubes were loaded until no void space remained after which samples were released and soaked in water. Stress /strain curves were recorded over the whole range of strain and cube thicknesses were recorded at the end of the compression, after release from the testing apparatus, and after soaking in water. Denser woods resulted in a greater Young’s modulus, higher levels of stress and shorter time to densification than did less dense woods. Higher initial moisture contents apparently increased the plasticity of the wood leading to a lower Young’s modulus and lower levels of stress during compression, greater springback after release of stress and greater recovery after swelling in water. Differences observed in the radial and tangential behaviours were believed to be due to the supporting action of the rays when the wood was compressed in the radial direction in balau and trembling aspen and to the relative difference between the lower density earlywood and higher density latewood regions in ash, Douglas-fir and western red cedar.

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