scholarly journals Modelling the effect of spacing and site exposure on spiral grain angle on Sitka spruce (Picea sitchensis (Bong.) Carr.) in Northern Britain

2013 ◽  
Vol 86 (3) ◽  
pp. 331-342 ◽  
Author(s):  
J. Fonweban ◽  
I. Mavrou ◽  
B. Gardiner ◽  
E. Macdonald
Keyword(s):  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Spiral Grain ◽  
Grain Angle ◽  
Spiral Grain Angle

scholarly journals Genetic parameters for spiral-grain angle in two 19-year-old clonal Norway spruce trials

2002 ◽  
Vol 59 (5-6) ◽  
pp. 551-556 ◽  
Author(s):  
Bj�rn Hannrup ◽  
Michael Grabner ◽  
Bo Karlsson ◽  
Ulrich M�ller ◽  
Sabine Rosner ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Genetic Parameters ◽  
Spiral Grain ◽  
Grain Angle ◽  
Spiral Grain Angle

Assessing Spiral Grain Angle by Light Transmission: – Proof of Concept –

IAWA Journal ◽  
2012 ◽  
Vol 33 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Mark Riddell ◽  
Dave Cown ◽  
Jonathan Harrington ◽  
John Lee ◽  
John Moore
Keyword(s):  
Light Transmission ◽  
Wood Properties ◽  
Assessment Method ◽  
Wood Products ◽  
Automated System ◽  
Angle Variation ◽  
Spiral Grain ◽  
Grain Angle ◽  
3 Dimensional ◽  
Spiral Grain Angle

Spiral grain measurements are subject to a high degree of variation and interpretation, depending on the assessment method used. A new measurement approach was tested whereby light was directed through disc samples on a flatbed scanner and the deviation along the grain assessed by means of a template to allow the mapping of grain angle variation radially and tangentially within discs. Initial results showed that the approach was valid for green discs up to 35 mm thick and small enough to fit on an A4 scanner. Comparisons with traditional scribing and cleaving methods were favourable, indicating that the light transmission approach could allow much faster and more accurate data acquisition. The possibility of using larger discs would enhance the ability to assess spatial variation in grain angle and minimise the effects of sample reference geometry with respect to the tree axis (disc tilt and parallax). Further work may also be required to ensure that reliable spiral grain values are obtained from both sapwood and heartwood. The ultimate goal is to develop an automated system for reconstructing stem characteristics from measurements on large fresh green discs to enable the 3-dimensional mapping of individual stem variations in key wood properties and modelling the impacts of silviculture and genetics on wood products.

Spiral grain in a clonal trial with Sitka spruce

1998 ◽  
Vol 28 (6) ◽  
pp. 911-919 ◽  
Author(s):  
Jon Kehlet Hansen ◽  
Hans Roulund
Keyword(s):  
Standard Deviation ◽  
Compression Wood ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Spiral Grain ◽  
Compass Direction ◽  
Phenotypic Standard Deviation ◽  
The Mean ◽  
Clonal Trial ◽  
Residual Variances

Grain angles to the left in seven clones of Sitka spruce (Picea sitchensis (Bong.) Carr.) decreased from the pith and outwards and with height. Effects of compression wood and compass directions were non-significant. Clones differed significantly but interacted with height levels, ring numbers, compass direction, and compression wood. However, the interaction with compression wood was small. Furthermore, some interaction with compass direction could possibly be attributed to eccentric stems and stem axis choice. The repeatability was 72% for averages of ramets measured in five height levels and most rings from the pith. The mean spiral grain was 2.2°, and the phenotypic standard deviation between averages of ramets was 1.07°. Genetic gains of 1° from phenotypic selections based on several measurements were suggested using these values. Variations between ramets and residual variances accounted for most of the variation. Thus, as many ramets as possible should be sampled to obtain the best estimates of mean clonal levels. Clone interactions with height levels and ring numbers from the pith were less important. This was also explained by correlations of 0.83–0.98 among clone averages at 1.3 m for single rings and overall clone means. Only significant effects ring widths were present within clones.

scholarly journals Differences in intra-tree variation in spiral grain angle for radiata pine

2013 ◽  
Vol 43 (1) ◽  
pp. 12 ◽  
Author(s):  
Michael S Watt ◽  
Mark O Kimberley ◽  
Jonathan J Harrington ◽  
Mark JC Riddell ◽  
Dave J Cown ◽  
...  
Keyword(s):  
Radiata Pine ◽  
Spiral Grain ◽  
Grain Angle ◽  
Spiral Grain Angle

Predicting the longitudinal modulus of elasticity of Sitka spruce from cellulose orientation and abundance

Holzforschung ◽  
2010 ◽  
Vol 64 (4) ◽  
Author(s):  
J. Paul McLean ◽  
Robert Evans ◽  
John R. Moore
Keyword(s):  
Bulk Density ◽  
Modulus Of Elasticity ◽  
Microfibril Angle ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Model Parameters ◽  
Bending Tests ◽  
Wood Stiffness ◽  
Using Data ◽  
Longitudinal Modulus

Abstract Sitka spruce (Picea sitchensis) is the most widely planted commercial tree species in the United Kingdom and Ireland. Because of the increasing use of this species for construction, the ability to predict wood stiffness is becoming more important. In this paper, a number of models are developed using data on cellulose abundance and orientation obtained from the SilviScan-3 system to predict the longitudinal modulus of elasticity (MOE) of small defect-free specimens. Longitudinal MOE was obtained from both bending tests and a sonic resonance technique. Overall, stronger relationships were found between the various measures of cellulose abundance and orientation and the dynamic MOE obtained from the sonic resonance measurements, rather than with the static MOE obtained from bending tests. There was only a moderate relationship between wood bulk density and dynamic MOE (R2=0.423), but this relationship was improved when density was divided by microfibril angle (R2=0.760). The best model for predicting both static and dynamic MOE involved the product of bulk density and the coefficient of variation in the azimuthal intensity profile (R2=0.725 and 0.862, respectively). The model parameters obtained for Sitka spruce differed from those obtained in earlier studies on Pinus radiata and Eucalyptus delegatensis, indicating that the model might require recalibration before it can be applied to different species.

Heritability of height growth in 10-year-old Sitka spruce

1985 ◽  
Vol 27 (6) ◽  
pp. 729-734 ◽  
Author(s):  
Francis C. Yeh ◽  
Sven Rasmussen
Keyword(s):  
Sitka Spruce ◽  
Height Growth ◽  
Picea Sitchensis ◽  
Breeding Program ◽  
Progeny Test ◽  
Northwest Coast ◽  
Phenotypic Variance ◽  
Family Selection ◽  
Sources Of Variation

Ten-year height growth for Picea sitchensis (Bong.) Carr. was studied in a progeny test of 42 wind-pollinated families from seven stands on the northwest coast of Vancouver Island. Although stand and family-within-stand effects were significant sources of variation, 79% of the phenotypic variance in 10-year height was associated with differences among trees within family plots. Estimates of heritability ([Formula: see text], [Formula: see text], and [Formula: see text]) indicate that a combination of stand, family-within-stand, and progeny-within-family selection will be effective for a long-term breeding program to increase tree heights in Sitka spruce.Key words: Picea, heritability, quantitative.

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