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

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.

Density and distribution of advance regeneration in mountain pine beetle killed lodgepole pine stands of the Montane Spruce zone of southern British Columbia

2008 ◽  
Vol 38 (11) ◽  
pp. 2826-2836 ◽  
Author(s):  
Gordon D. Nigh ◽  
Joseph A. Antos ◽  
Roberta Parish
Keyword(s):  
British Columbia ◽  
Spatial Distribution ◽  
Mountain Pine Beetle ◽  
Lodgepole Pine ◽  
Spatial Scales ◽  
South Central ◽  
Advance Regeneration ◽  
Mountain Pine ◽  
Pine Beetle ◽  
Pine Stands

Insect outbreaks, such as the current mountain pine beetle ( Dendroctonus ponderosae Hopkins) outbreak in lodgepole pine ( Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) forests in British Columbia, are major disturbances in many forests. After an insect outbreak, the advance regeneration typically forms a new canopy, which may be adequate for timber objectives in some stands. Our purpose was to quantify and then model the abundance and spatial distribution of advance regeneration (trees <10.0 m tall). We sampled understory and overstory trees in 28 lodgepole pine stands in south-central British Columbia at two spatial scales: 0.1 ha plots and 25 m2 subplots. We developed models predicting advance regeneration abundance and spatial distribution. Density of advance regeneration averaged 2689 trees/ha (range 120 to 23 000 trees/ha), most of which were <1 m tall. Although advance regeneration was clumped, 75% of the subplots contained at least one individual. Models indicated negative relationships of advance regeneration abundance to overstory basal area and density. Over half the stands had enough advance regeneration to form new stands of adequate density, indicating that use of advance regeneration is a viable option in this mountain pine beetle outbreak and probably other insect disturbances.

Nest tree use by primary cavity-nesting birds in south central British Columbia

1989 ◽  
Vol 67 (4) ◽  
pp. 1067-1073 ◽  
Author(s):  
Alton S. Harestad ◽  
Dagmar G. Keisker
Keyword(s):  
British Columbia ◽  
Populus Tremuloides ◽  
Douglas Fir ◽  
Trembling Aspen ◽  
Diameter At Breast Height ◽  
Breast Height ◽  
South Central ◽  
Cavity Nesting ◽  
Picoides Pubescens ◽  
Colaptes Auratus

Heartwood decay was the most important factor in nest tree selection by primary cavity-nesting birds in the Interior Douglas-fir Biogeoclimatic Zone of British Columbia. Of 243 active nests, most were in trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera). Douglas-fir (Pseudotsuga menziesii) and hybrid spruce (Picea engelmannii × glauca) were not used for nesting. Strong excavators (Yellow-bellied Sapsucker (Sphyrapicus varius), Pileated Woodpecker (Dryocopus pileatus), and Hairy Woodpecker (Picoides villosus)) preferred to nest in live trembling aspen with heartwood decay. Weak excavators (Red-breasted Nuthatch (Sitta canadensis), Northern Flicker (Colaptes auratus), and Downy Woodpecker (Picoides pubescens)) preferred to nest in dead trees or dead tops of live trees. Yellow-bellied Sapsucker preferred to nest in trees larger than 30 cm diameter at breast height, and Pileated Woodpecker preferred trees larger than 40 cm diameter at breast height. No significant preference for nest tree diameter was detected for other species.

Some Aspects of the Morphometry of Paraglacial Alluvial Fans in South-central British Columbia

1971 ◽  
Vol 8 (10) ◽  
pp. 1252-1264 ◽  
Author(s):  
J. M. Ryder
Keyword(s):  
British Columbia ◽  
Arid Region ◽  
Arid Regions ◽  
Alluvial Fans ◽  
Statistical Relationship ◽  
Regression Analyses ◽  
South Central ◽  
Relationship Of ◽  
Relief Area ◽  
Mud Flow

The construction of paraglacial alluvial fans commenced during deglaciation and was dependent upon the temporary abundance of glacially formed debris. Correlation and regression analyses for five groups of fans located within the Interior valleys of south-central British Columbia, indicate that fan gradient is significantly related to the relative relief, area, height, and slope of associated basins. These factors exerted an influence upon fan geometry through processes of stream and mud-flow deposition.Paraglacial fans are distinguished from fans of arid regions by their steeper gradients and a weaker statistical relationship of fan gradient with basin parameters which is subject to greater variation between local regions. This is attributed to the plentiful supply of glacial drift and local changes in its character. Since the basins of most paraglacial fans were formed preglacially, whereas arid region fans and associated basins were formed concurrently, a weaker control of basin character upon fan geometry is to be expected for the former.

Barking Damage by Red Squirrels in Juvenile-spaced Lodgepole Pine Stands in South-Central British Columbia

1987 ◽  
Vol 63 (1) ◽  
pp. 28-31 ◽  
Author(s):  
R. P. Brockley ◽  
E. Elmes
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Average Diameter ◽  
Practical Method ◽  
Growth And Yield ◽  
Damage Potential ◽  
Red Squirrels ◽  
South Central ◽  
The Impact ◽  
Fire Origin

A survey was undertaken to assess the incidence and magnitude of barking injuries by red squirrels in juvenile stands of spaced lodgeppole pine in south-central British Columbia. Eleven of the 40 stands surveyed (27.5%) showed evidence of squirrel damage. Within damaged stands, an average of 51% of lodgepole pine crop trees exhibited barking injuries (ranging from 6 to 90%).The average diameter (6.8 cm) of damaged stands was significantly greater than that of undamaged stands (3.9 cm). Sixty-seven percent of stands with average diameters greater than 6 cm showed evidence of barking injuries, while only 11% of stands with average diameters less than 6 cm had been damaged. Squirrels preferentially attacked the larger-diameter stems in damaged stands. Data indicate that fire-origin stands are more susceptible to barking damage than stands naturally regenerated following harvesting.Inability to accurately assess either squirrel damage potential or its impact on growth and yield indicates that a conservative approach is necessary in spacing juvenile lodgepole pine in areas susceptible to squirrel attack. A two-step spacing strategy may be the most practical method of minimizing the impact of squirrel barking injuries. Key words: lodgepole pine, juvenile-spacing, red squirrels.

Assessment of interspecific competition using relative height and distance indices in an age sequence of seral interior cedar–hemlock forests in British Columbia

2004 ◽  
Vol 34 (6) ◽  
pp. 1228-1240 ◽  
Author(s):  
Suzanne W Simard ◽  
Donald L Sachs
Keyword(s):  
British Columbia ◽  
Interspecific Competition ◽  
Douglas Fir ◽  
Thuja Plicata ◽  
Stand Age ◽  
Relative Height ◽  
Larix Occidentalis ◽  
Critical Height ◽  
Paper Birch ◽  
Neighbourhood Analysis

Treatments that reduce neighbour density are widely applied in the belief they will improve conifer growth in mixed forests. However, our understanding of stand composition and age effects on competition is poor. We used neighbourhood analysis for 748 target conifer trees to examine interspecific competition within 11-, 25-, and 50-year-old mixed, even-aged stands of paper birch (Betula papyrifera Marsh.), Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), western redcedar (Thuja plicata Donn ex D. Don), and western larch (Larix occidentalis Nutt.) in southern interior British Columbia. Critical neighbourhood height and distance were identified where competition accounted for the greatest variation in target conifer diameter. Competition processes were emperically examined using relative height indices. We found that critical neighbourhood distance increased with stand age and was greater for larch than for cedar. Critical neighbourhood height was higher for cedar than for Douglas-fir or larch in the 11-year-old stands but lower in the older stands. The most important competitors in the 11-year-old stands were tall neighbours, whereas those in the older stands were short neighbours. We found asymmetrical relationships between target conifers and neighbours for all species and age-classes, indicating a resource preemption mode of competition. To be useful in developing prescriptions for competition management in mixed species stands, competition indices should consider neighbour identity and critical height for each target species. Assessment radius must also be sufficiently large to adequately characterize competition.

scholarly journals Growth of Douglas-fir, lodgepole pine, and ponderosa pine seedlings underplanted in a partially-cut, dry Douglas-fir stand in south-central British Columbia

2006 ◽  
Vol 82 (5) ◽  
pp. 723-732 ◽  
Author(s):  
Alan Vyse ◽  
Christine Ferguson ◽  
Suzanne W Simard ◽  
Tamaki Kano ◽  
Pasi Puttonen
Keyword(s):  
British Columbia ◽  
Soil Moisture ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Lodgepole Pine ◽  
Basal Area ◽  
Light Level ◽  
Douglas Fir ◽  
Partial Cutting ◽  
South Central

The effects of partial cutting on seedling growth of three conifer species were studied at a very dry, hot interior Douglas-fir site near Kamloops, British Columbia. Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), and ponderosa pine (Pinus ponderosa Dougl. ex. P. & C. Laws.) seedlings were planted in mechanically prepared 50 cm × 50 cm patches under different canopy conditions created by harvesting 60% of the original stand volume. The prepared areas were selected to represent canopy closures from open to closed, slopes from 0 to 60%, and all aspects. After six years, survival of Douglas-fir, lodgepole pine and ponderosa pine was 78%, 76% and 70%, respectively. Light level had a strong influence on survival and condition. Growth of all species increased linearly with light, and was greatest for lodgepole pine, followed by ponderosa pine and Douglas-fir. Multiple regression analysis showed that six-year seedling size was most significantly affected by total light, and only occasionally by aspect, slope, or crown closure. The best models explained 53%, 47% and 42% of the variation in diameter of lodgepole pine, ponderosa pine, and Douglas-fir, respectively. Natural abundance 13C was positively correlated with light and soil moisture availability, reflecting higher photosynthetic capacity of all species in the wetter, open canopy conditions. Patterns in isotopic discrimination also indicated greater water use efficiency of Douglas-fir and ponderosa pine than lodgepole pine under low light conditions. Underplanting stands thinned to a basal area of less than 15m2 per ha offers a solution to regeneration difficulties on hot, dry Interior Douglas-fir sites. Key words: partial cutting, Douglas-fir, lodgepole pine, ponderosa pine, light, soil moisture, 13C, growth, survival, Opax Mountain Silvicultural Systems Project

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