Within- and between-stand variation in selected properties of Sitka spruce sawn timber in the UK: implications for segregation and grade recovery

Moore, John R.; Lyon, Andrew; Searles, Gregory J; Lehneke, Stefan; Ridley-Ellis, Daniel

doi:10.1007/s13595-013-0275-y

Cited by 47 publications

(36 citation statements)

References 21 publications

(26 reference statements)

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“…This was also found by Moore et al (2013) in a study of Sitka spruce from UK. Even though the level of the properties was different in their study, the proportions of the different variance components were similar.…”

Section: Discussionsupporting

confidence: 74%

Between- and within-site variation of density and bending properties ofPicea abiesstructural timber from Norway

Vestøl

Fischer

Høibø

et al. 2016

Scandinavian Journal of Forest Research

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This study provides an analysis on the variability of structural timber of Norway spruce (Picea abies) grown in Norway. Density, modulus of elasticity (MOE) and bending strength were measured on 1188 boards from 205 trees, sampled from 14 sites throughout Southern Norway, Eastern Norway and Trøndelag. The area represents the procurement area for the majority of Norwegian sawmills. The variability of the timber properties was analysed in a linear mixed model where the random variance was divided into variance due to site, variance due to trees and within-tree variance. Models describing variance due to site based on site index, altitude and latitude were developed, and combined with data from the Norwegian National Forest Inventory to estimate mean values and variability of the timber properties. The results showed that major parts of the variance due to site are explained by altitude and site index, and for density also by latitude. Major parts of the variance due to site and the variance due to trees in bending strength and MOE were explained by density. ARTICLE HISTORY

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Section: Discussionsupporting

confidence: 74%

Between- and within-site variation of density and bending properties ofPicea abiesstructural timber from Norway

Vestøl

Fischer

Høibø

et al. 2016

Scandinavian Journal of Forest Research

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“…The negative and significant correlation observed between crown ratio and MOE at tree and board level was also reported for other coniferous species such as Picea mariana (Liu et al, 2007) and Picea sitchensis (Moore et al, 2013).…”

Section: Effect Of Site Tree and Stand Variables On Mean Tree Moe Trsupporting

confidence: 74%

Modelling modulus of elasticity of Pinus pinaster Ait. in northwestern Spain with standing tree acoustic measurements, tree, stand and site variables

et al. 2014

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IntroductionPinus pinaster Ait. is one of the most important coniferous species used in the timber industry in Spain, especially in Galicia (NW Spain) where it covers around 587,000 ha of land and is the main forest industry resource. More than 2.8 million cubic meters of Pinus pinaster round wood are produced annually in Galicia, representing 72% of the total production of the species in Spain. Recent studies have demonstrated the good mechanical properties of Galician P. pinaster timber, which make it suitable for structural use (Riesco and Díaz González, 2007;Carballo et al., 2009).Forest management and climatic and soil factors have important effects on softwood properties (e.g. Lasserre et al., 2004;Moore et al., 2009;Roth et al., 2007;Watt et al., 2006;. Studies carried out in different regions have assessed the influence of these factors on the variation in wood properties in coniferous species (e.g. Lei et al., 2005;Liu et al., 2007, or Ikonen et al., 2008. The use of portable acoustic devices that estimate timber stiffness from measurements made on standing trees (e.g. Wang et al., 2001b;Merlo et al., 2008Merlo et al., , 2009Santaclara et al., 2011) is a key element of these studies. Stiffness (quantified by the modulus of elasticity, MOE) is an important mechanical property of timber and it is commonly measured in machine grading of timber strength. It is also the index parameter considered by Abstract Aim of study:Modelling the structural quality of Pinus pinaster Ait. wood on the basis of measurements made on standing trees is essential because of the importance of the species in the Galician forestry and timber industries and the good mechanical properties of its wood. In this study, we investigated how timber stiffness is affected by tree and stand properties, climatic and edaphic characteristics and competition.Area of study: The study was performed in Galicia, north-western Spain. Material and methods:Ten pure and even-aged P. pinaster stands were selected and tree and stand variables and the stress wave velocity of 410 standing trees were measured. A sub-sample of 73 trees, representing the variability in acoustic velocity, were felled and sawed into structural timber pieces (224) which were subjected to a bending test to determine the modulus of elasticity (MOE).Main results: Linear models including wood properties explained more than 97%, 73% and 60% of the observed MOE variability at site, tree and board level, respectively, with acoustic velocity and wood density as the main regressors. Other linear models, which did not include wood density, explained more than 88%, 69% and 55% of the observed MOE variability at site, tree and board level, respectively, with acoustic velocity as the main regressor. Moreover, a classification tree for estimating the visual grade according to standard UNE 56544:2011 was developed.Research highlights: The results have demonstrated the usefulness of acoustic velocity for predicting MOE in standing trees. The use of the fitted equations together with existing d...

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“…Ranta-Maunus et al 2011, "Gradewood Project") and on the opportunities to improve the timber resource through tree breeding, forest management and resource segregation (e.g. Moore et al 2013, Baltrušaitis and Pranckevičienė 2012, Rais et al 2014. It is known that there is considerable variation of wood properties within a tree (related to the biomechanics of tree growth), but also a crucial geographical variation that is caused, in part, by environmental and silvicultural factors and, therefore, varies with time.…”

Section: The Origin Of Variation In Timber Propertiesmentioning

confidence: 99%

“…Moore et al 2013, Baltrušaitis and Pranckevičienė 2012, Rais et al 2014, diverting the better quality material to construction timber and the poorer material to other markets and reducing wastage. As methods of resource segregation become more effective this would allow decisions to be made about what strength classes to grade to for optimum value yield, but this raises the question as to whether the practice of resource segregation compromises existing grading settings and assignments for the reasons outlined in 5.…”

Section: Pre-grading and Resource Segregationmentioning

confidence: 99%

Strength grading of sawn timber in Europe: an explanation for engineers and researchers

2016

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This paper is a concise explanation of the normative background to strength grading in Europe, addressing important aspects that are commonly misunderstood by structural engineers and timber researchers. It also highlights changes that are being made to the standards to: incorporate requirements of the Construction Products Regulations; add improvements to the system to accommodate the latest knowledge and technology; and widen the application of the standards.Where designs need to be optimised, there is an opportunity to use the system more intelligently, in combination with the latest technology, to better fit design values to the true properties of the timber resource. This can bring a design enhancement equivalent to effort improving other aspects of the structure, such as connectors and reinforcement. Parallel to this, researchers working on other aspects of structural improvement need to understand what grades really mean in respect of the properties of the timber, in order to correctly analyse the results of testing. It is also useful to know how techniques used in grading can assist with material properties characterisation for research.The amount of destructive testing involved in establishing machine grading settings and visual grading assignments presents a barrier to greater use of local timber, and diversification of commercial species, so it is important that any researcher assessing the properties of such species should consider, from the outset, doing the research in a way that can contribute to a grading dataset at a later date. This paper provides an overview of what is required for this.

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Within- and between-stand variation in selected properties of Sitka spruce sawn timber in the UK: implications for segregation and grade recovery

Abstract: International audienc

Cited by 47 publications

References 21 publications

Between- and within-site variation of density and bending properties ofPicea abiesstructural timber from Norway

Between- and within-site variation of density and bending properties ofPicea abiesstructural timber from Norway

Modelling modulus of elasticity of Pinus pinaster Ait. in northwestern Spain with standing tree acoustic measurements, tree, stand and site variables

Strength grading of sawn timber in Europe: an explanation for engineers and researchers

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