Differences in crown characteristics between black (<i>Picea mariana</i>) and white spruce (<i>Picea glauca</i>)

Power, Hugues; LeMay, Valerie; Berninger, Frank; Sattler, Derek F.; Kneeshaw, Daniel

doi:10.1139/x2012-106

Cited by 32 publications

(10 citation statements)

References 25 publications

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“…4 and 5), because it is strongly correlated with crown dimensions (Sharma et al 2016a). Since crown recession and height growth of trees are two important factors of HCB dynamics, any changes to them result in a significant change on the crown dimensions (Power et al 2012;Sharma et al 2016a), and consequently on the CDBDR. When the lower branches die, this results in a crown recession, which leads to a larger HCB and a narrower crown.…”

Section: Discussionmentioning

confidence: 99%

“…Crown recession is largely affected by competitive interaction among trees (Valentine et al 2013), light availability to the lower branches, and physical interactions with neighboring trees. Trees growing in a crowded stand or trees with larger crowns may experience more physical interactions with neighboring trees, resulting in increased crown recession (Power et al 2012). Crowns of tall trees are also subject to considerable movement due to wind-blow and resulting collisions may lead to substantial abrasion of branches and foliage (Rudnicki et al 2003).…”

Section: Discussionmentioning

confidence: 99%

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Modelling tree crown-to-bole diameter ratio for Norway spruce and European beech

Sharma¹,

Vacek²,

Vacek³

2017

Silva Fenn.

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Highlights• Modelled crown-to-bole diameter ratio (CDBDR) using tree and stand-level predictors, and sample plot random effects.• Spatially explicit mixed-effects model described the largest part of CDBDR variation with no significant trend in the residuals.• The CDBDR increased with increasing stand development stage and site quality, but decreased with decreasing proportion of the species of interest, and increasing competition. AbstractCrown dimensions are correlated to growth of other parts of a tree and often used as predictors in growth models. The crown-to-bole diameter ratio (CDBDR), which is a ratio of maximum crown width to diameter at breast height (DBH), was modelled using data from permanent sample plots located on Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) stands in different parts of the Czech Republic. Among various tree and stand-level measures evaluated, DBH, height to crown base (HCB), dominant height (HDOM), basal area of trees larger in diameter than a subject tree (BAL), basal area proportion of the species of interest (BAPOR), and Hegyi's competition index (CI) were found to be significant predictors in the CDBDR model. Random effects were included using the mixed-effects modelling to describe sample plot-level variation. For each species, the mixed-effects model described a larger part of the variation of the CDBDR than nonlinear ordinary least squares model with no trend in the residuals. The spatially explicit mixed-effects model showed more attractive fit statistics [conditional R 2 ≈ 0.73 (spruce), 0.78 (beech)] than its spatially inexplicit counterpart [conditional R 2 ≈ 0.71 (spruce), 0.76 (beech)]. The model showed that CDBDR increased with increasing HDOM -a measure that combines the stand development stage and site quality -but decreased with increasing HCB and competition (increasing BAL and CI), and decreasing proportions of the species of interest (increasing BAPOR). For both species, the spatially explicit mixed-effects model should be a preferred choice for a precise prediction of the CDBDR. The CDBDR model will have various management implications such as determination of spacing, stand basal area, stocking, and planning of appropriate species mixture.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Modelling tree crown-to-bole diameter ratio for Norway spruce and European beech

Sharma¹,

Vacek²,

Vacek³

2017

Silva Fenn.

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“…A plot-specific tree height model was parameterized to estimate unmeasured tree heights (details are provided in Power et al 2012). Once all unmeasured heights were imputed, the dominant height (DH) of each plot was calculated by averaging the height of the 100 largest trees per hectare.…”

Section: Datamentioning

confidence: 99%

“…Once all unmeasured heights were imputed, the dominant height (DH) of each plot was calculated by averaging the height of the 100 largest trees per hectare. With stand age obtained from increment cores collected on three dominant trees of the stand at 1 m height, dominant height was used to estimate site index with Pothier and Savard's (1998) After felling, total sample tree height and height to live crown were measured to the nearest centimeter. Height to live crown was considered as the height of the lowest branch that presented green foliage and above which all the whorls included at least one living branch.…”

Section: Datamentioning

confidence: 99%

Crown characteristics slightly improve lumber mechanical property models for black spruce (Picea mariana(Mill.) BSP)

Power

Franceschini

Schneider

et al. 2016

The Forestry Chronicle

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Most models of modulus of elasticity (MOE) and modulus of rupture (MOR) use classical dendrometric variables and do not use crown characteristics that are known to influence wood formation and properties. The objective of this study was to evaluate the benefit of including crown variables in black spruce MOE and MOR models. Values of MOE and MOR were measured on 99 boards from 21 black spruce trees located in nine stands in the Lac-Saint-Jean region of Québec (Canada). Site, tree and crown variables (crown surface area, crown length, branch basal area) were measured. Stand age and basal area were found to be positively related to MOE and MOR. Stem DBH and crown length were negatively related to MOE and MOR. When including crown variables, Akaike's Information Criterion was stable while the R 2 increased slightly (+ 2.7% for MOE and + 1% for MOR). The small benefit in model performance associated with the inclusion of crown variables in MOE and MOR models suggests that models without crown variables could be used for industrial purposes without much loss in performance.Key words: modulus of elasticity, modulus of rupture, crown characteristics, black spruce RÉSUMÉLa plupart des modèles de module d' élasticité (MOE) et de module de rupture (MOR) utilisent des variables dendromé-triques standards, mais pas les caractéristiques du houppier reconnues pour influencer la formation du bois et ses propriétés. Cette étude avait pour but d' évaluer l'intérêt d'utiliser les variables de houppier dans les modèles de MOE et de MOR pour l' épinette noire. Les valeurs du MOE et du MOR ont été mesurées sur 99 pièces de bois obtenues de 21 tiges d' épinette noire provenant de l' épinette noire réparties dans neuf peuplements de la région du Lac-Saint-Jean, au Québec (Canada). Les mesures ont porté sur les variables de la station, des arbres ainsi que des cimes (superficie de la cime, longueur de la cime, surface terrière). On a observé que l'âge du peuplement et la surface terrière étaient corrélées de façon positive avec le MOE et le MOR. Le dhp des tiges et la longueur des cimes montraient une corrélation négative avec le MOR et le MOE. En incluant les variables des cimes, le critère d'information d' Akaike s'avère stable tandis que le R2 s'accroît légèrement (+ 2,7 % pour le MOE et + 1 % pour le MOR). Le peu de gain dans la performance du modèle lié à l'inclusion des variables de la cime dans les modèles du MOE et du MOR indique que les modèles sans les variables de la cime pourraient être utilisés à des fins industrielles sans diminution importante au niveau de la performance.Mots clés : module d' élasticité, module de rupture, caractéristiques de la cime, épinette noire

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“…Rupšys (2015) developed stochastic models of crown widths. Power et al (2012) proposed equations of crown length, profile, shape and surface area of black spruce (Picea mariana) and white spruce (Picea glauca) to characterize crown characteristics of these species. Sattler and LeMay (2011) proposed a simultaneous system of nonlinear equations to predict crown length and crown radius in structurally complex stands.…”

Section: Introductionmentioning

confidence: 99%

Analytical approaches for modeling tree crown volume in black wattle (Acacia mearnsii De Wild.) stands

Guilherme¹,

Carlos²,

Sylvio³

et al. 2016

Afr. J. Agric. Res.

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In this paper, four strategies were proposed for modeling tree crown volume using as independent variable stem variables, crown variables, combination of stem and crown variables, and stem volume. We used a dataset comprised of 170 trees from 12 temporary plots located in forest stands in southern Brazil. Models composed of stem variables presented weaker predictive ability. The best model contained crown variables, which explained 78.95% of observed variability. However, implementation of such model is bounded by its independent variables, which are not often measured in forest inventories. The model composed by diameter at breast height and crown length proved to be an adequate modeling approach. The predictive capability was kept by model , which is composed by most easily measured variable in a forest -diameter at breast height, also by the most easily acquirable crown variable -crown length. In our suggested model, estimates of and are coefficients that convert volume of a regular geometric solid -RGS is dbh² times crown length) -into crown volume, whilst estimate of is an allometric constant.

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Differences in crown characteristics between black (Picea mariana) and white spruce (Picea glauca)

Cited by 32 publications

References 25 publications

Modelling tree crown-to-bole diameter ratio for Norway spruce and European beech

Modelling tree crown-to-bole diameter ratio for Norway spruce and European beech

Crown characteristics slightly improve lumber mechanical property models for black spruce (Picea mariana(Mill.) BSP)

Analytical approaches for modeling tree crown volume in black wattle (Acacia mearnsii De Wild.) stands

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