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  • 1
    Language: English
    In: Canadian journal of forest research, 2020, Vol.50 (2), p.81-88
    Description: We present a new method to estimate individual knot volumes based on a knot geometry model coupled with observations on branch characteristics. X-ray computer tomography and image analysis were used to measure the volume and geometry of 424 knots of Sitka spruce (Picea sitchensis (Bong.) Carrière). Knot geometry can be described mathematically by deriving functions for relative vertical position, diameter, and slope dependent on radial position in the stem. These functions were parameterized using “seemingly unrelated regression” and mixed-modelling techniques. This provided a base model for typical knots. To estimate individual knot volume, we used available data for branch diameter and insertion angle to obtain conditional predictions. We imputed the most likely knot trajectory, as relative vertical position cannot be measured on branches. The model explained up to 96% of the variability in knot volume by incorporating the branch measurements, in contrast to the 43% explained using the typical knot model. Knot volume assessment based only on conditional predictions of diameter and marginal predictions of vertical position also accounted for 96% of the variability. Therefore, measurements of branch diameter alone would be enough to obtain highly precise predictions of individual knot volume. This estimator is a first step towards a knot model to be used for the management of Sitka spruce in Great Britain.
    Subject(s): Sitka spruce ; épinette de Sitka ; knot geometry ; seemingly unrelated regression ; régression sans relation apparente ; géométrie des nœuds ; mixed models ; BLUPs ; méthode BLUP de Henderson ; modèle à effets mixtes
    ISSN: 0045-5067
    E-ISSN: 1208-6037
    Source: Academic Search Ultimate
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  • 2
    Language: English
    In: Canadian journal of forest research, 2018, Vol.48 (8), p.857-868
    Description: Due to the high amount of low-quality hardwoods harvested during selection cuts, the forest industry has been facing a decline in profit margins. One possible solution for utilizing the low-quality raw material is the production of extracts. The objective of this work was to estimate to what extent the inclusion of betulin in the traditional wood products portfolio could extend the profitability of a hardwood value chain. The profitability of a selection cut was assessed from the sawmill perspective, followed by an evaluation of the potential financial gain of producing betulin. Finally, the inclusion of betulin in a value chain was assessed. Results showed that the profitability of selection cuts was very low in some forest stands. The sensitivity analysis demonstrated that, among selected costs and revenues, profit was more sensitive to variations in the value of coproducts. If a fraction of coproducts volume was used to extract betulin, it would be sufficient to generate enough revenue to offset the total costs; however, a major constraint was the small size of the current betulin market, with annual sales not exceeding 1000 kg. Despite that, results demonstrate the potentially strong contribution of high value added extracts to the profitability of the forest value chain.
    Subject(s): hardwoods ; bouleau jaune ; yellow birch ; selection cut ; coupe de jardinage ; value chain ; chaîne de valeur ; extracts ; extractibles ; feuillus ; By-products ; Value chain ; Economic aspects ; Research ; Terpenes ; Production processes ; Sawmills
    ISSN: 0045-5067
    E-ISSN: 1208-6037
    Source: Academic Search Ultimate
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  • 3
    Language: English
    In: Canadian journal of forest research (Print), 2014, Vol.44 (2), p.162-171
    Description: Radial patterns of modulus of elasticity (MOE) were examined for white spruce (Picea glauca (Moench) Voss) and trembling aspen (Populus tremuoides Michx.) from 19 mature, uneven-aged stands in the boreal mixedwood region of northern Alberta, Canada. The main objectives were to (1) evaluate the relationship between pith-to-bark changes in MOE and cambial age or distance from pith; (2) develop species-specific models to predict pith-to-bark changes in MOE; and (3) to test the influences of radial growth, relative vertical height, and tree slenderness (tree height/DBH) on MOE. For both species, cambial age was selected as the best explanatory variable with which to build pith-to-bark models of MOE. For white spruce and trembling aspen, the final nonlinear mixed-effect models indicated that an augmented rate of increase in MOE occurred with increasing vertical position within the tree. For white spruce trees, radial growth and slenderness were found to positively influence maximum estimated MOE. For trembling aspen, there was no apparent effect of vertical position or radial growth on maximum MOE. The results shed light on potential drivers of radial patterns of MOE and will be useful in guiding silvicultural prescriptions.
    Subject(s): Fundamental and applied biological sciences. Psychology ; Biological and medical sciences ; Forestry ; Spruce ; Wood ; Physiological aspects ; Elasticity ; Arboriculture ; Properties ; Aspen
    ISSN: 0045-5067
    E-ISSN: 1208-6037
    Source: Academic Search Ultimate
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  • 4
    Language: English
    In: Forests, 2019-06-01, Vol.10 (6), p.500
    Description: Careful logging around small merchantable stems (CLASS) is a partial cutting treatment that consists of the harvest of 70%-90% of the merchantable volume of an irregular coniferous stand. In this treatment, regeneration, saplings and small merchantable stems (DBH 〈 15 cm) are preserved and can continue to grow and develop into the dominant layer of the new stand. The aim of this project was to examine the effects of CLASS on the primary and secondary growth of branches, as well as on branch diameter in black spruce and balsam fir trees in the boreal forest of Quebec, Canada. Primary and secondary growth were measured on five branches per tree while branch diameter was analysed from 15 whorls distributed within the crown of the 48 black spruce and 48 balsam fir trees sampled. Branch primary and secondary growth significantly increased after CLASS in the lower part of the crown in both species, and both types of growth increased proportionally. These findings suggest that CLASS may delay crown recession as the lower branches tend to survive and grow for a longer period. However, although radial growth increased in the years post-CLASS, this did not significantly influence the final branch diameter and should not lead to lumber downgrade.
    Subject(s): Life Sciences & Biomedicine ; Forestry ; Science & Technology ; branch diameter ; radial growth ; Picea mariana (Mill.) B.S.P ; Apical shoot length ; partial cutting ; Abies balsamea (L.) Mill
    ISSN: 1999-4907
    E-ISSN: 1999-4907
    Source: Web of Science - Science Citation Index Expanded - 2019〈img src="http://exlibris-pub.s3.amazonaws.com/fromwos-v2.jpg" /〉
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
    Source: ProQuest Central
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  • 5
    Language: English
    In: Sensors (Basel, Switzerland), 2013-03-12, Vol.13 (3), p.3394-3408
    Description: This study investigates how the use of a Hitman ST300 acoustic sensor can help identify the best forest stands to be used as supply sources for the production of Machine Stress-Rated (MSR) lumber. Using two piezoelectric sensors, the ST300 measures the velocity of a mechanical wave induced in a standing tree. Measurements were made on 333 black spruce (Picea mariana (Mill.) BSP) trees from the North Shore region, Quebec (Canada) selected across a range of locations and along a chronosequence of elapsed time since the last fire (TSF). Logs were cut from a subsample of 39 trees, and sawn into 77 pieces of 38 mm × 89 mm cross-section before undergoing mechanical testing according to ASTM standard D-4761. A linear regression model was developed to predict the static modulus of elasticity of lumber using tree acoustic velocity and stem diameter at 1.3 m above ground level (R2 = 0.41). Results suggest that, at a regional level, 92% of the black spruce trees meet the requirements of MSR grade 1650Fb-1.5E, whilst 64% and 34% meet the 2100Fb-1.8E and 2400Fb-2.0E, respectively. Mature stands with a TSF 〈 150 years had 11 and 18% more boards in the latter two categories, respectively, and therefore represented the best supply source for MSR lumber.
    Subject(s): Canada ; Trees - ultrastructure ; Acoustics - instrumentation ; Humans ; Forestry ; Quebec ; wood stiffness ; acoustic sensors ; machine stress-rated lumber ; forestry wood chain
    ISSN: 1424-8220
    E-ISSN: 1424-8220
    Source: Academic Search Ultimate
    Source: PubMed Central
    Source: Alma/SFX Local Collection
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  • 6
    Language: English
    In: Canadian journal of forest research, 2013, Vol.43 (3), p.278-287
    Description: Stems of sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britt.) trees often contain a column of discoloured wood known as red heartwood, which reduces lumber value. To quantify the regional-scale variation in red heartwood, 192 trees of each species were sampled in 12 locations across the temperate forest zone of southern Quebec, Canada. Large regional variation in the radial proportion of red heartwood (RHP) at breast height (1.3 m) was observed in both species. Statistical modeling showed that such variation was mainly attributable to factors related to tree development. Cambial age had a strong positive effect on RHP in both species, suggesting that the occurrence of red heartwood ultimately might be unavoidable. There was also a positive effect of ring area increment at the limit of the discoloured zone. In the case of sugar maple, there was an added effect of the trend in ring area increments observed in the same zone, with a negative trend being generally indicative of a larger RHP. Further variability in this species was also associated with the annual minimum temperature of the sampling locations. The models developed for each species explained around 60% of the variance in RHP and could be used to improve forest management and wood procurement decisions.
    Subject(s): Fundamental and applied biological sciences. Psychology ; Biological and medical sciences ; Forestry ; Trees ; Forest management ; Observations ; Sustainable forestry ; Analysis
    ISSN: 0045-5067
    E-ISSN: 1208-6037
    Source: Academic Search Ultimate
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  • 7
    Language: English
    In: Plant and soil, 2018-12, Vol.433 (1), p.111-125
    Description: Forest composition in North America has undergone important changes since the European settlement. The effects of such alterations on soil properties remain largely unknown. This study aims to understand the long-term effects of shifts in forest composition on soil properties.Using data from 130 plots measured over an eighty-year period, the relationships between stand composition (both current and past), parent material and current soil chemical properties were studied with redundancy analyses.Results indicated that the parent material remained the dominant factor explaining soil properties, followed by current tree species composition. No legacy effect of past forest composition was found, but shifts in forest composition explained part of the current soil properties. Specifically, an increase in balsam fir was related to higher C/N ratio in the O-horizon, while an increase in maple species was related to higher net nitrification in both the O and B-horizons, and higher extractable P in the B-horizon.Our results suggest that increasing the maple component at the expense of conifers over several decades may enhance nutrient availability in the O-horizon.
    Subject(s): Life Sciences ; Plant-soil relationship ; Soil chemical composition ; Plant Physiology ; Ecology ; Plant Sciences ; Shifts in forest composition ; Mixed forests ; Redundancy analysis ; Soil Science & Conservation ; Nitrification ; Chemical properties
    ISSN: 0032-079X
    E-ISSN: 1573-5036
    Source: Academic Search Ultimate
    Source: Alma/SFX Local Collection
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  • 8
    Language: English
    In: Forests, 2013-07-10, Vol.4 (3), p.575-594
    Description: There is a growing interest to use acoustic sensors for selection in tree breeding to ensure high wood quality of future plantations. In this study, we assessed acoustic velocity as a selection trait for the improvement of mechanical wood properties in two 15- and 32-year-old white spruce (Picea glauca [Moench.] Voss) genetic tests. Individual heritability of acoustic velocity was moderate and of the same magnitude as heritability of wood density. Considerable genetic gain could be expected for acoustic velocity and a measure combining velocity and wood density. The relationship between acoustic velocity and cellulose microfibril angle (MFA) was strong on the genetic level and selection based on velocity could effectively improve MFA, which is one of the most important determinants of wood mechanical properties. Although low, the positive relationship between acoustic velocity and tree height presents an interesting opportunity for the improvement of both tree growth and wood quality. On the phenotypic level, MFA was more strongly correlated to acoustic velocity in mature trees than in young trees. The addition of easily obtainable traits such as diameter at breast height (DBH), height-to-diameter ratio as well as wood density to velocity determinations could improve models of MFA at the young and the mature age. We conclude that juvenile acoustic velocity is an appropriate trait to select for wood quality in a tree breeding context.
    Subject(s): white spruce ; ST300 ; acoustic velocity ; selection efficiency ; wood quality ; tree breeding
    ISSN: 1999-4907
    E-ISSN: 1999-4907
    Source: DOAJ Directory of Open Access Journals - Not for CDI Discovery
    Source: ProQuest Central
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  • 9
    Language: English
    In: Canadian journal of forest research, 2014, Vol.44 (7), p.750-759
    Description: The identification of low-vigor trees with potential for sawlog production is a key objective of tree marking guidelines used for partial cuts in northern hardwoods. The aim of this study was to measure the impact of various vigor-related defects on the monetary value of hardwoods. To achieve this, we sampled 64 sugar maple (Acer saccharum Marshall) and 32 yellow birch (Betula alleghaniensis Britton) trees from two locations in southern Quebec, Canada. We identified over 420 defects, which were grouped into 8 categories. The trees were then harvested and processed into lumber, and the value per unit volume of each stem was calculated from the value of the product assortment (lumber, chips, and sawdust). We found that visible evidence of fungal infections (sporocarps and (or) stroma) and cracks had the largest negative influence on value in both species. A model that included these defects was almost as good at predicting value as one that included a specifically designed quality classification. A more accurate assessment of value could be achieved using wood decay assessment tools and (or) by considering site-specific variables. Results from this study showed that visual identification of fungal infections and cracks could be used to enhance tree marking guidelines for hardwoods. This would meet both the silvicultural objective of selection cuts, by removing low-vigor trees, and the wood supply objective, by improving stem quality assessment prior to harvest.
    Subject(s): hardwoods ; tree vigor ; vigueur des arbres ; defects ; défauts ; tree marking ; tree quality ; martelage ; qualité des arbres ; feuillus ; Fundamental and applied biological sciences. Psychology ; Biological and medical sciences ; Forestry ; Forest management ; Forestry research ; Research ; Forest productivity
    ISSN: 0045-5067
    E-ISSN: 1208-6037
    Source: Academic Search Ultimate
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  • 10
    Language: English
    In: Canadian journal of forest research, 2014, Vol.44 (6), p.638-647
    Description: Realistic forestry value chain simulations require accurate representations of each component. For primary processing, this is complicated by the fact that a single raw material is converted into a wide range of lumber products. The aim of this study was to develop statistical models for predicting lumber product assortment from tree size information, while taking into account the high proportion of zeros in the data. Lumber recovery was simulated from a database of 1013 laser-scanned Picea mariana (Mill.) Britton, Sterns & Poggenb. and Abies balsamea (L.) Mill. stems using the sawing simulator Optitek. The number of boards per stem of specific products was modelled with zero-inflated Poisson regression using stem diameter and height as covariates. The number of boards per stem was strongly related to both diameter and height, but also changed according to input prices for lumber products. Zero-inflated models outperformed ordinary Poisson regression in all cases. The developed models will be integrated into simulation tools designed to optimize processes along the entire forest value chain from forest to end user.
    Subject(s): Abies balsamea ; optimisation ; optimization ; régression de Poisson à excès de zéros ; lumber product assortment ; composition du panier de produits sciés ; sawing simulation ; zero-inflated Poisson regression ; Picea mariana ; Fundamental and applied biological sciences. Psychology ; Biological and medical sciences ; Generalities. Production, biomass. Quality of wood and forest products. General forest ecology ; Quality of wood and forest products ; Forestry ; Poisson's equation ; Production management ; Forest products ; Sawing ; Models ; Research ; Mathematical optimization ; Varieties
    ISSN: 0045-5067
    E-ISSN: 1208-6037
    Source: Academic Search Ultimate
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