Predicting sustained smouldering combustion in trembling aspen duff in Elk Island National Park, Canada

2007 ◽  
Vol 16 (6) ◽  
pp. 690 ◽  
Author(s):  
S. G. Otway ◽  
E. W. Bork ◽  
K. R. Anderson ◽  
M. E. Alexander
Keyword(s):  
Populus Tremuloides ◽  
Experimental Test ◽  
National Park ◽  
Clear Understanding ◽  
Trembling Aspen ◽  
Fire Weather Index ◽  
Inorganic Content ◽  
Elk Island National Park ◽  
Aspen Forest ◽  
Smouldering Combustion

Fire is one of the key disturbances affecting trembling aspen (Populus tremuloides Michx.) forest ecosystems within western Canadian wildlands, including Elk Island National Park in central Alberta, Canada. Although prescribed fire is a tool available to modify aspen forests, a clear understanding of its potential impact is necessary to successfully manage this disturbance. Undesirable social and ecological consequences of severe, deep-burning ground fires include smoke generation and impaired vegetation regrowth. Data on the duff moisture conditions under which ground or subsurface fires may ignite and spread in aspen forest duff layers are presented, as well as experimental test fire results. Different topographic positions, plant communities and seasonality were factored into the research design. The Duff Moisture Code (DMC) and Drought Code (DC) components of the Canadian Forest Fire Weather Index System were calculated and factors including duff moisture content, bulk density and inorganic content measured before ignition of experimental test fires. Probability of sustained smouldering combustion models were developed for the duff layer in the aspen forest fuel type in Elk Island National Park, with values of 27 for DMC and 300 for DC at the 50% probability level.

Relating changes in duff moisture to the Canadian Forest Fire Weather Index System in Populus tremuloides stands in Elk Island National Park

2007 ◽  
Vol 37 (10) ◽  
pp. 1987-1998 ◽  
Author(s):  
S. G. Otway ◽  
E. W. Bork ◽  
K. R. Anderson ◽  
M. E. Alexander
Keyword(s):  
Forest Fire ◽  
Populus Tremuloides ◽  
Index System ◽  
National Park ◽  
National Standard ◽  
Fire Weather ◽  
Weather Index ◽  
Fire Weather Index ◽  
Elk Island National Park ◽  
Topographic Positions

The manner in which trembling aspen ( Populus tremuloides Michx.) forest duff moisture changes during the growing season was investigated in Elk Island National Park, Alberta, Canada. A calibration–validation procedure incorporating one calibration site with moisture sampling across three topographic positions was used to develop predictive models, which were subsequently compared with 12 validation sites across three vegetation types throughout the Park. Duff moisture was modelled against the Duff Moisture Code and Drought Code components of the Canadian Forest Fire Weather Index System. Spring, summer, and fall rates of duff moisture change differed (P < 0.050) during calibration, with moisture loss greatest in spring. Additionally, while moisture changes on the south-facing and crest topographic positions were similar during spring, moisture losses were greater (P < 0.050) at these locations compared with the north-facing landscape position. Correlation analysis indicated that duff inorganic content and bulk density were both related to duff moisture but were limited in importance compared with weather-based influences. When compared with predicted values obtained from calibrated models, moderate predictability of duff moisture was found (mean absolute error = 20.7%–54.2%). Relative to the national standard equations, unique but very different empirical relationships were developed between the Duff Moisture Code and Drought Code and the moisture content of the duff layer in aspen forest stands found in Elk Island National Park.

NOTES ON HYLPOXYLON CANKER OF ASPEN IN ALBERTA

1967 ◽  
Vol 43 (4) ◽  
pp. 372-380 ◽  
Author(s):  
J. A. Baranyay
Keyword(s):  
Populus Tremuloides ◽  
National Park ◽  
Trembling Aspen ◽  
Infection Period ◽  
Elk Island National Park ◽  
Stem Cankers

The rate of canker growth, caused by HYPOXYLON PRUINATUM (Klotzsch) Cke. (H. MAMMATUM (Wahl.) Miller) and the intensification of the disease were investigated on trembling aspen, POPULUS TREMULOIDES Michx. in Elk Island National Park, Alberta. In 1963, 45.1 per cent of the trees on a 1/3-acre plot were either killed or infected. This number increased to 49.0 per cent during the following three years. All stem cankers were located below the 9 foot level and 75.0 per cent were facing north or northeast. The disease was not confined to a particular crown class. Infected, trees were killed in 4 to 8 years. Fifteen cankers were sectioned to study the nature of canker growth. The rate of girdling was not related to either the diameter or dominance of the tree. The cankers grew at a faster rate on dominant and co-dominant trees during the initial year of infection than on intermediate and overtopped trees. The disease did not cause increment loss during the infection period.

scholarly journals Prescribed Burning Has Limited Long-Term Effectiveness in Controlling Trembling Aspen (Populus tremuloides) Encroachment into Fescue Grassland in Prince Albert National Park

2013 ◽  
Vol 127 (1) ◽  
pp. 50 ◽  
Author(s):  
Digit D. Guedo ◽  
Eric G. Lamb
Keyword(s):  
Populus Tremuloides ◽  
National Park ◽  
Prescribed Burning ◽  
Woody Species ◽  
System Structure ◽  
Forest Transition ◽  
Trembling Aspen ◽  
Prescribed Burn ◽  
Grassland Community ◽  
Prince Albert National Park

Encroachment into grassland by woody species is a global ecological phenomenon, and it is of particular concern in remnant fescue (Festuca) prairie at the aspen parkland–boreal forest ecotone. Fire suppression is thought to encourage encroachment; however, prescribed burning as a means of controlling encroachment and restoring system structure, function, and composition has had variable success. The objective of this study was to determine the effects of different season of burn, number of annual burns, and number of years after burning treatments on Trembling Aspen (Populus tremuloides) encroachment into the fescue grasslands within Prince Albert National Park, Saskatchewan. Temporal changes in density and cover of Trembling Aspen in grassland and grassland–forest transition plant communities were evaluated using data from a prescribed burn study conducted in Prince Albert National Park from 1975 to 2010. The effect of year (indicating varying amounts of time relative to prescribed burning) and the interaction between spring burning and year reflect a stimulatory effect of burning on Trembling Aspen suckering. Increased Trembling Aspen cover in the forest transition community with more annual burns, burning in the fall, and the interaction between year and number of annual burns and increased Trembling Aspen cover in the grassland community with year indicate that none of the treatments had lasting control of Trembling Aspen encroachment. Ongoing Trembling Aspen encroachment despite prescribed burning may be due to important missing interactions between fire and grazing. A change in the use and expectation of prescribed burning is needed when attempting to suppress Trembling Aspen encroachment into the fescue grasslands.

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.

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

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.

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

1973 ◽  
Vol 51 (2) ◽  
pp. 498-500 ◽  
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.

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.

THE BEHAVIOUR OF FIVE WOOD SPECIES IN COMPRESSION

IAWA Journal ◽  
2002 ◽  
Vol 23 (2) ◽  
pp. 201-211 ◽  
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.

scholarly journals Distribution, Morphology, Survival, and Genetics of Aspen (Populus Tremuloides) Seedlings Following the 1988 Yellowstone Fires

1996 ◽  
Vol 20 ◽  
pp. 118-122
Author(s):  
Monica Turner ◽  
Rebecca Reed ◽  
William Romme ◽  
Gerald Tuskan
Keyword(s):  
Populus Tremuloides ◽  
Yellowstone National Park ◽  
National Park ◽  
Plant Competition ◽  
Mineral Soil ◽  
Rare Event ◽  
Weather Conditions ◽  
Elevational Gradient ◽  
Quaking Aspen ◽  
Burned Areas

An unexpected consequence of the 1988 Yellowstone fires was the widespread establishment of seedlings of quaking aspen (Populus tremuloides) in the burned forests, including areas outside the previous range of aspen (Kay 1993; Romme et al. 1997). Although aspen is the most widely distributed tree species in North America (Powells 1965), it is relatively uncommon and localized in distribution within Yellowstone National Park (Despain 1991). Most aspen stands in Yellowstone are found in the lower elevation landscapes in the northern portion of the park, and the species was absent - prior to 1988 -- across most of the high plateaus that dominate the southern and central park area. Aspen in the Rocky Mountain region reproduces primarily by means of vegetative root sprouting. Although viable seeds are regularly produced, establishment of seedlings in the wild is apparently a rare event due to the limited tolerance of aspen seedlings for desiccation or competition (e.g., Pearson 1914; McDonough 1985). In the immediate aftermath of the 1988 Yellowstone fires, there was a brief "window of opportunity" for aspen seedling establishment, as a result of abundant aspen seed production, moist weather conditions in spring and summer, and bare mineral soil and reduced plant competition within extensive burned areas (Jelinski and Cheliak 1992; Romme et al. 1997). We initiated this 3-year study in 1996 to address four questions about the aspen seedlings now growing in burned areas across the Yellowstone Plateau: (1) What are the broad-scale patterns of distribution and abundance of aspen seedlings across the subalpine plateaus of Yellowstone National Park? (2) What is the morphology and population structure -- e.g., proportions of genets (genetic individuals that developed from a single seed) and ramets (vegetative root sprouts produced by a genet) of various ages - in aspen seedling populations? (3) What are the mechanisms leading to eventual persistence or extirpation of seedling populations along an elevational gradient, particularly with respect to ungulate browsing and plant competition? (4) What is the genetic diversity and relatedness of the seedling populations along gradients of elevation and substrate?

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