Evaluation of relationships between understory light and aspen basal area in the British Columbia central interior

Comeau, Philip G.; Heineman, Jean L.; Newsome, Teresa A.

doi:10.1016/j.foreco.2005.12.060

Cited by 38 publications

(48 citation statements)

References 39 publications

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“…White spruce may also establish naturally in the understory of mature aspen stands when there is a local spruce seed source [7]. Light levels under fully-stocked boreal aspen stands reach minimum levels of 5% of full sunlight between 10 and 25 years after disturbance [8], but increase to 15% to 20% of full sunlight or higher at around age 40, which is adequate to allow establishment of white spruce [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…Several studies demonstrate that aspen can reduce growth of overtopped white spruce when it is present at densities above about 1000 st ha´1 (stems per hectare) [12,13]. Studies also indicate that reducing aspen densities can increase light levels [10,12] and spruce growth [14][15][16]. Treatments which reduce competition from aspen and other broadleaved trees can provide substantial increases in growth of white spruce [17,18].…”

Section: Introductionmentioning

confidence: 99%

“…Reducing aspen densities by manual brushing or herbicide treatments can improve growing conditions for white spruce [16,18]. Studies in northern British Columbia and Alberta indicate that light levels underneath aspen canopies are related to the basal area of aspen [8,10]. Comeau et al [10] suggest that maintaining total aspen basal area below 8 m 2 ha´1 may provide near optimal light conditions for growth of white spruce.…”

Section: Introductionmentioning

confidence: 99%

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Managed Mixtures of Aspen and White Spruce 21 to 25 Years after Establishment

Kabzems

Bokalo

Comeau

et al. 2015

Forests

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Intimate mixtures of trembling aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench) Voss) are a key feature of western Canadian boreal forests. These mixtures have the potential to produce high yields of merchantable fibre and provide numerous ecological services. Achievement of this potential has been difficult, and often expensive, to realize as a regeneration goal in managed forests. We report 21 to 25 year results of managed mixtures on two study sites where the white spruce was planted, and the density of aspen natural regeneration manipulated within five years of the stand initiation disturbance. On both sites, white spruce mortality did not increase with increasing aspen density. While height and diameter growth of white spruce declined with increasing aspen density, the effect was not entirely consistent across the two sites. Abrasion from aspen branches was the most common source of damage to spruce crowns. Mixed stands had greater merchantable volume production than pure spruce stands based on model projections. Application of aspen harvest at year 60, while protecting the spruce component for a second harvest entry at year 90, was projected to optimize combined yield for the mixedwood stands.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Managed Mixtures of Aspen and White Spruce 21 to 25 Years after Establishment

Kabzems

Bokalo

Comeau

et al. 2015

Forests

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“…Some progress has been made. We now know that within a relatively small geographic range in south-central British Columbia, aspen has greater ability to intercept light and to compete with neighbouring lodgepole pine in productive Sub-Boreal Spruce (SBS) ecological units than in the drier, less productive Interior Douglas-fir (IDF), and the even drier and colder Sub-Boreal Pine Spruce (SBPS) units [9][10][11][12]. However, competitive interactions have been highly variable between sites even within the same ecological unit, which Filipescu and Comeau [13] also observed for trembling aspen-white spruce (Picea glauca (Moench) Voss) interactions.…”

Section: Introductionmentioning

confidence: 99%

“…Knowing whether relative height relationships between trembling aspen and lodgepole pine 2 International Journal of Forestry Research are changing with time would help us evaluate the potential for aspen to have ongoing competitive impacts on lodgepole pine as stands age. Trembling aspen crown characteristics and their ability to intercept light have also been linked to stem size [12,14], so examining the distribution of basal area among individual competing aspen stems could also contribute to our understanding of competition differences between ecological units. Finally, in addition to increasing our understanding of aspen's competitive ability, greater focus on aspen in its own right could provide important management information as climate change proceeds and our valuation of the forest resource shifts.…”

Section: Introductionmentioning

confidence: 99%

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

Newsome

Heineman²,

Nemec³

2012

International Journal of Forestry Research

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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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Solar radiation transmission in and around canopy gaps in an uneven-aged Nothofagus betuloides forest

et al. 2009

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The transmission of direct, diffuse and global solar radiation in and around canopy gaps occurring in an uneven-aged, evergreen Nothofagus betuloides forest during the growing season (October 2006-March 2007) was estimated by means of hemispherical photographs. The transmission of solar radiation into the forest was affected not only by a high level of horizontal and vertical heterogeneity of the forest canopy, but also by low angles of the sun's path. The below-canopy direct solar radiation appeared to be variable in space and time. On average, the highest amount of transmitted direct solar radiation was estimated below the undisturbed canopy at the southeast of the gap centre. The transmitted diffuse and global solar radiation above the forest floor exhibited lower variability and, on average, both were higher at the centre of the canopy gaps. Canopy structure and stand parameters were also measured to explain the variation in the below-canopy solar radiation in the forest. The model that best fit the transmitted below-canopy direct solar radiation was a growth model, using plant area index with an ellipsoidal angle distribution as the independent variable (R (2) = 0.263). Both diffuse and global solar radiation were very sensitive to canopy openness, and for both cases a quadratic model provided the best fit for these data (R (2) = 0.963 and 0.833, respectively). As much as 75% and 73% of the variation in the diffuse and global solar radiation, respectively, were explained by a combination of stand parameters, namely basal area, crown projection, crown volume, stem volume, and average equivalent crown radius.

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Evaluation of relationships between understory light and aspen basal area in the British Columbia central interior

Cited by 38 publications

References 39 publications

Managed Mixtures of Aspen and White Spruce 21 to 25 Years after Establishment

Managed Mixtures of Aspen and White Spruce 21 to 25 Years after Establishment

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

Solar radiation transmission in and around canopy gaps in an uneven-aged Nothofagus betuloides forest

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