Timber quality classes from cruise data for lodgepole pine sawn at a board mill in British Columbia

1991 ◽  
Vol 21 (4) ◽  
pp. 498-503
Author(s):  
Andrew F. Howard
Keyword(s):  
British Columbia ◽  
Regression Analysis ◽  
Lodgepole Pine ◽  
Likelihood Ratio Tests ◽  
Grading System ◽  
Timber Quality ◽  
Wide Range ◽  
Commercial Species ◽  
Appreciable Variation ◽  
Lumber Grade

Information on timber quality can play an important role in a wide range of planning activities at sawmills. A system for assessing timber quality does not exist for lodgepole pine (Pinuscontorta Dougl.), which is one of the most important commercial species in the interior of British Columbia. A classification system for lodgepole pine timber was developed from cruise data collected according to procedures prescribed by the British Columbia Ministry of Forests. A sawmill lumber yield study was made to obtain the data necessary to test the grading system. Regression analysis, likelihood ratio tests, and analysis of variance were used to test for significant differences in lumber grade yields and log values among six quality classes. The findings indicate that data collected during cruising can be used to separate timber into distinct quality classes. The quality classes showed appreciable variation in average log value when current lumber prices were applied.

scholarly journals Trembling Aspen Removal Effects on Lodgepole Pine in Southern Interior British Columbia: Ten-Year Results

2009 ◽  
Vol 24 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Jean L. Heineman ◽  
Suzanne W. Simard ◽  
Donald L. Sachs ◽  
W. Jean Mather
Keyword(s):  
British Columbia ◽  
Regression Analysis ◽  
Populus Tremuloides ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Average Density ◽  
Douglas Fir ◽  
Stem Diameter ◽  
Trembling Aspen ◽  
Density Threshold

Abstract Manual cutting treatments are routinely applied to release lodgepole pine (Pinus contorta var. latifolia Engelm.) from trembling aspen (Populus tremuloides Michx.) competition in southern interior British Columbia. We studied the effects of this treatment on pine and an aspen-dominated community on three sites in the Interior Douglas-Fir and Montane Spruce biogeoclimatic zones. After 10 years, when stands were 17–20 years old, treated aspen was significantly shorter than control aspen, and treated pine had significantly (21%) larger diameter than control pine. There were few other differences between brushed and unbrushed pine, and survival was excellent (≥97%), regardless of treatment. Brushing nearly doubled the average density of conifer stems that were free-growing according to legislated standards, but results were variable, and the free-growing status of the stand was changed on only one site. Regression analysis was used to examine the correlation between aspen abundance and pine size. The density of aspen at least as tall as the pine (tall aspen) predicted 36.2% of the variation in pine diameter, and total aspen density predicted 35.9% of the variation in pine height. An average density threshold of 1,867 tall aspen stems/ha, above which pine stem diameter declined, was identified in the three stands.

scholarly journals Spore Dispersal by Dothistroma septosporum in Northwest British Columbia

2015 ◽  
Vol 105 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Kennedy Boateng ◽  
Kathy J. Lewis
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Summer Precipitation ◽  
Disease Spread ◽  
Spore Dispersal ◽  
Mixed Species ◽  
Inoculum Sources ◽  
Pine Trees ◽  
Dothistroma Septosporum ◽  
Needle Blight

We studied spore dispersal by Dothistroma septosporum, causal agent of a serious outbreak of red band needle blight in lodgepole pine plantations in northwest British Columbia. Spore abundance was assessed at different distances and heights from inoculum sources and microclimatic factors were recorded during two consecutive years. Conidia were observed on spore traps from June to September during periods of rainfall. It was rare to detect spores more than 2 m away from inoculum sources. The timing and number of conidia dispersed were strongly tied to the climatic variables, particularly rainfall and leaf wetness. Should the trend toward increased spring and summer precipitation in the study area continue, the results suggest that disease spread and intensification will also increase. Increasing the planting distances between lodgepole pine trees through mixed species plantations and overall reduction in use of lodgepole pine for regeneration in wet areas are the best strategies to reduce the spread of the disease and enhance future productivity of plantations in the study area.

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.

scholarly journals Unravelling the impact of harvesting pressure on canopy-forming macroalgae

2016 ◽  
Vol 67 (1) ◽  
pp. 153 ◽  
Author(s):  
Doriane Stagnol ◽  
Renaud Michel ◽  
Dominique Davoult
Keyword(s):  
Habitat Characteristics ◽  
Spatiotemporal Variability ◽  
Macrobenthic Assemblages ◽  
Wide Range ◽  
The Matrix ◽  
Commercial Species ◽  
Canopy Removal ◽  
The Impact ◽  
Relevant Finding

Canopy-forming macroalgae create a specific surrounding habitat (the matrix) with their own ecological properties. Previous studies have shown a wide range of responses to canopy removal. Magnitude and strength of the effects of harvesting are thought to be context-dependent, with the macroalgal matrix that can either soften or exacerbate the impact of harvesting. We experimentally examined in situ the effect of harvesting on targeted commercial species, and how these potential impacts might vary in relation to its associated matrix. We found that patterns of recovery following the harvesting disturbance were variable and matrix specific, suggesting that local factors and surrounding habitat characteristics mediated the influence of harvesting. The greatest and longest effects of harvesting were observed for the targeted species that created a dominant and monospecific canopy on their site prior to the disturbance. Another relevant finding was the important natural spatiotemporal variability of macrobenthic assemblages associated with canopy-forming species, which raises concern about the ability to discriminate the natural variability from the disturbance impact. Finally, our results support the need to implement ecosystem-based management, assessing both the habitat conditions and ecological roles of targeted commercial species, in order to insure the sustainability of the resource.

scholarly journals Comparison between Online and Offline Price of Tobacco Products Using Novel Datasets

2018 ◽  
Vol 15 (10) ◽  
pp. 2282 ◽  
Author(s):  
Magdalena Opazo Breton ◽  
John Britton ◽  
Yue Huang ◽  
Ilze Bogdanovica
Keyword(s):  
Regression Analysis ◽  
Real Time ◽  
Control Measure ◽  
Data Sources ◽  
Tobacco Products ◽  
Product Range ◽  
Daily Data ◽  
Wide Range ◽  
Commercial Sources ◽  
Price Differences

Price of tobacco products has traditionally been relevant both for the industry, to respond to policy changes, and for governments, as an effective tobacco control measure. However, monitoring prices across a wide range of brands and brand variants requires access to expensive commercial sales databases. This study aims to investigate the comparability of average tobacco prices from two commercial sources and an in-house monitoring database which provides daily data in real time at minimal cost. We used descriptive and regression analysis to compare the monthly average numbers of brands, brand variants, products and prices of cigarettes and hand-rolling tobacco using commercial data from Nielsen Scantrack and Kantar Worldpanel, and an online price database (OPD) created in Nottingham, for the period from May 2013 to February 2017. There were marked differences in the number of products tracked in the three data sources. Nielsen was the most comprehensive and Kantar Worldpanel the least. Though average prices were very similar between the three datasets, Nottingham OPD prices were the highest and Kantar Worldpanel the lowest. However, regression analysis demonstrated that after adjustment for differences in product range, price differences between the datasets were very small. After allowing for differences in product range these data sources offer representative prices for application in price research. Online price tracking offers an inexpensive and near real-time alternative to the commercial datasets.

scholarly journals Fungal colonizers and seed loss in lodgepole pine orchards of British Columbia

Botany ◽  
2019 ◽  
Vol 97 (1) ◽  
pp. 23-33
Author(s):  
Paul Y. de la Bastide ◽  
Jonathon LeBlanc ◽  
Lisheng Kong ◽  
Terrie Finston ◽  
Emily M. May ◽  
...  
Keyword(s):  
British Columbia ◽  
Seed Production ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Seed Viability ◽  
Molecular Approaches ◽  
Seed Loss ◽  
Natural Range ◽  
Fungal Microbiome ◽  
Host Tissues

Lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) is an important lumber species in Canada, and seed orchards are expected to meet the increased demand for seed. However, seed production has been consistently low in the Okanagan region orchards of British Columbia, Canada. To determine whether the fungal microbiome contributes to seed loss, histological and molecular approaches were used. Seed production was studied at seven Okanagan orchards, all outside the natural range of lodgepole pine, and at one near Prince George, within its natural range. Seed losses were highest in the Okanagan, compared with Prince George. The role of fungal colonizers in consuming seed during the last stages of maturation is described. Fungal hyphae were frequently observed at all locations in developing seed, particularly once storage substances accumulated. Fungi identified from host tissues using molecular and morphological techniques included Alternaria, Cladosporium, Fusarium, Penicillium, and Sydowia. The opportunistic foliar pathogen Sydowia polyspora, which is known to have a variable biotrophic status, was detected at most orchards within different host tissues (seeds, needles, and conelets), in association with pollen, and in the air column. Reduced seed viability observed in Okanagan orchards is most likely due to a combination of factors, including composition of the fungal microbiome.

scholarly journals Reliability of Nitrogen Content (%N) and Carbon:Nitrogen Atomic Ratios (C:N) as Indicators of Collagen Preservation Suitable for Radiocarbon Dating

Radiocarbon ◽  
2012 ◽  
Vol 54 (3-4) ◽  
pp. 879-886 ◽  
Author(s):  
Fiona Brock ◽  
Rachel Wood ◽  
Thomas F G Higham ◽  
Peter Ditchfield ◽  
Alex Bayliss ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Linear Regression ◽  
Radiocarbon Dating ◽  
Linear Regression Analysis ◽  
Atomic Weight ◽  
Animal Bones ◽  
Bone Powder ◽  
Wide Range ◽  
Pass Through ◽  
Percent Nitrogen

A recent study into prescreening techniques to identify bones suitable for radiocarbon dating from sites known for poor or variable preservation (Brock et al. 2007, 2010a) found that the percent nitrogen (%N) content of whole bone powder was the most reliable indicator of collagen preservation. Measurement of %N is rapid, requires little preparation or material, and is relatively cheap. The technique reduces the risk of needlessly sampling valuable archaeological objects, as well as saving time and money on their unsuccessful pretreatment prior to dating. This method of prescreening is now regularly used at the Oxford Radiocarbon Accelerator Unit (ORAU). In the original study, linear regression analysis of data from 100 bones from 12 Holocene sites across southern England showed that when 0.76% N was chosen as a threshold, 84% of bones were successfully identified as containing sufficient (i.e. >1%) or insufficient (i.e. <1%) collagen for dating. However, it has been observed that for older, Pleistocene bones the failure rate may be higher, possibly due to the presence of more degraded, short-chain proteins that pass through the ultrafilters used in pretreatment, resulting in lower yields. Here, we present linear regression analysis of data from nearly 600 human and animal bones, antlers, and teeth, from a wide range of contexts and ages, to determine whether the 0.76% threshold identified in the previous study is still applicable. The potential of carbon:nitrogen atomic weight ratios (C:N) of whole bone to predict collagen preservation is also discussed.

scholarly journals Exploring Purpose as a Resource for Promoting Youth Program Engagement

2018 ◽  
Vol 13 (4) ◽  
pp. 164-178 ◽  
Author(s):  
Anthony L. Burrow ◽  
Jennifer P. Agans ◽  
Nicolette Rainone
Keyword(s):  
Regression Analysis ◽  
Purpose In Life ◽  
Writing Intervention ◽  
Learning Engagement ◽  
Academic Tasks ◽  
Negatively Associated ◽  
Youth Program ◽  
Age Related ◽  
Wide Range ◽  
Program Engagement

Recent evidence that reflecting on one’s purpose in life increases engagement with academic tasks inspires questions about whether purpose interventions might enhance learning engagement more broadly. This potential may be particularly fruitful for programs serving youth from a wide range of ages wherein sustaining engagement may be challenging. Here, we explored whether a brief purpose writing intervention would increase adolescents’ engagement in 4-H programs. Participants (N = 130) were randomly assigned to write about either their sense of purpose or a control topic prior to the first day of a program, and they reported their level of program engagement at the end of that day. Regression analysis showed participant age was negatively associated with program engagement. However, writing about purpose halted this age-related decline in engagement. These preliminary findings situate purpose as a resource that can be leveraged to sustain older youths’ interest and engagement in youth programming.

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