The mechanism of spiral grain formation in trees

Schulgasser, K.; Witztum, A.

doi:10.1007/s00226-006-0100-y

Cited by 20 publications

(18 citation statements)

References 63 publications

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“…The parameters a and b, estimated from observations in cross-cut samples, were found to be bivariate normally distributed a ~ N(2.74, 1.92) and b ~ N(-0.0387, 0.0371) and slightly correlated (r = -0.27) in a sample of 1046 crosscuts (Gjerdrum et al 2002). This model, corresponding to the causative explanation proposed by Schulgasser and Witztum (2007), implies a constant change rate in grain angle throughout the life of a tree, irrespective of external stimuli. Both the initial angle near the pith a and the change rate b vary randomly between trees.…”

Section: Introductionmentioning

confidence: 69%

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Three-dimensional spiral grain pattern in five large Norway spruce stems

Gjerdrum¹,

Bernabei²

2009

Silva Fenn.

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GjerdrumThere is a great deal of interest involved in investigating and understanding grain angle in trees. The objective of the study presented in this paper has been to identify a joint, threedimensional model for grain angle in stems of Norway spruce (Picea abies (L.) Karst.) Five large spruce trees were sampled. Transverse disks were extracted at regular intervals along the stem, split through the pith with a blunt knife, and observed for grain angle and cambial age along the north radius, setting pith observation to zero angle. The overall finding confirmed grain pattern congruent to distance from pith along the stem, a pattern that varies from tree to tree. Models expressing distance from the pith in cambial age performed slightly better than models in spatial distance. Grain pattern changed slightly along the stem, and this change was found to be consistent for the five stems: the left-handed grain angle in the juvenile wood was more pronounced upwards in the stem, and the angle changed faster towards right-handed spiralling. The model did not account for grain variation related to knots, undulating pith or other irregularities. Model residuals were normally distributed and seemingly homogeneous for all trees and for all height levels. The model is an extension of existing two-dimensional models for stem cross-cuts. After verification in a wider sample, the results should be applicable in tree and wood modelling.

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Section: Introductionmentioning

confidence: 69%

“…from the general tendency of a maturing cell to take on a preferred inclination with respect to the cell which immediately preceded it in its file." (Cited from Schulgasser and Witztum 2007).…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional spiral grain pattern in five large Norway spruce stems

Gjerdrum¹,

Bernabei²

2009

Silva Fenn.

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“…Past studies have shown that the MFA has to be ruled out from the list of possible factors causing the existence of spiral grain (Foulger 1966;Harris 1989), given that the grain angles are almost certainly determined by cambial orientation in the early formation of the fiber cells, while the MFA within the second layer is formed by the microtubules and made into its final structure in the late formation of the fiber cells (Harris 1989;Barnett & Bonham 2004). An explanation is offered by a biomechanical theory which takes MFA into account as an influencing factor of spiral grain formation associated with maturation growth stresses (Schulgasser & Witztum 2007). This theory explains that reaction wood, or wood with high growth stresses which was caused by the angled grain-which includes the wood with wavy grain-will form cells with larger MFA.…”

Section: Discussionmentioning

confidence: 99%

Relationships between anatomical and vibrational properties of wavy sycamore maple

Alkadri¹,

Carlier²,

Wahyudi³

et al. 2018

IAWA Journal

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Sycamore maple (Acer pseudoplatanus L.) is a wood species particularly known for its wavy grain figure and its high-value utilization among luthiers and craftsmen for making musical instruments or furniture. In this study, the anatomical and physical-acoustical characteristics of its wood, taken from different trees with various surface figure, were characterized. Vibrational mechanical measurements were conducted taking into account radial and longitudinal directions and local variations, waviness' parameters were quantified on split blocks, and anatomical properties such as microfibril angle and rays' dimensions were measured using light microscopy. Results provide a complete dataset on the properties of sycamore maple showing a gradient of wavy figure. Through statistical analysis, it can be concluded that there exist significant correlations between the measured parameters, particularly between waviness and microfibril angle, and between these anatomical features and the specific modulus of elasticity and damping by internal friction of the wood in longitudinal direction. Anisotropy was found to be very low but was not satisfactorily explained by the studied anatomical features. Prospects for future studies on wavy figure are introduced.

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“…Spiral grain angle (SGA) is defined as the orientation of wood fibres or tracheids with respect to the longitudinal axis of the tree stem (Kozlowski et al 1967). Changes in the grain angle within stems are a well-known feature of old trees and of the corewood of conifers, and are normally attributed to pseudotransverse and anticlinal cell division in the vascular cambium (Bannan 1966;Larson 1994;Schulgasser and Witztum 2007). Spiral grain is an important defect is sawn timber and is a primary source of twist distortion during drying (Ormarsson and Cown 2005).…”

Section: Introductionmentioning

confidence: 99%

Modelling spiral grain angle variation in New Zealand-grown radiata pine

Moore

Cown

McKinley

2015

N.Z. j. of For. Sci.

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Background: Spiral grain angle (SGA) is a wood property that has a strong influence on end-product quality, particularly for solid timber, and most commercial log and timber grading rules restrict the amount of visible surface sloping grain. The aim of this study was to develop parametric models that can be used to predict the intra-and inter-stem variation in SGA in radiata pine (Pinus radiata D.Don) trees growing in New Zealand. Methods: Empirical models were developed using a dataset that contained records from over 1,100 trees that had SGA measured in both the radial direction and at different heights up the stem. Linear and nonlinear model forms were evaluated for their ability to predict the radial variation in SGA.Results: Most values of spiral grain angle were between −5°and +10°, with a few extreme values (up to 20°) observed. A simple linear model based on cambial age was able to account for the radial variation in SGA outside of the innermost growth rings, but only explained 26 % of the overall variation in SGA. Including a relative height term in this linear model increased the proportion of variation in SGA explained to 30 %. A variance components analysis showed that 78 % of the variation in SGA occurred within individual stems, with only 7 % of the variation due to differences between sites. Conclusions: Our results confirmed that SGA decreased from the inner growth rings to the bark and increased with height up the stem, with low values of SGA only found in the lower peripheral part of the stem. Given that the data came from a wide range of sites, the relatively small amount of inter-site variation was unexpected. The models developed here can be incorporated into a growth and yield simulation system to enable forest managers to compare the potential impacts of different factors on the size of the corewood zone in a tree containing wood with high SGA.

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The mechanism of spiral grain formation in trees

Cited by 20 publications

References 63 publications

Three-dimensional spiral grain pattern in five large Norway spruce stems

Three-dimensional spiral grain pattern in five large Norway spruce stems

Relationships between anatomical and vibrational properties of wavy sycamore maple

Modelling spiral grain angle variation in New Zealand-grown radiata pine

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