Research Output
The non-destructive evaluation of Sitka spruce mechanical properties using acoustic methods
  The need for improved timber grading is key to improving Scottish forestry: the majority (80%) of the sustainable softwood population in Scotland is Sitka spruce of variable quality. Current visual assessment of strength and stiffness is inaccurate, and machine stress grading in sawmills is little better due to incorrect assumptions regarding consistency within softwood species and between trees of the same stand. The author develops and evaluates non-destructive test (NOT) methods for Scottish Sitka spruce based upon impact-e9ho testing across a range of scales from plank, to log, to standing tree.
Correlations between harmonic wave propagation velocity and elastic modulus of 0.62 ::; R2 ::; 0.71 were possible in Sitka spruce under a range of conditions including: genotype progeny, variable height and radial position in stem, and
variable knot content. In achieving this correlation, the research also investigated acoustic parameters such as: time of flight velocity, damping ratio, and resonant peak behaviour with regard to their influence on dynamically derived moduli of elasticity. Examination of variation in wood properties (including static elastic modulus, knot content, simulated decay, density, and grain alignment) on these acoustic parameters was conducted on semi-controlled specimens of differing homogeneities. The consequences of these results should influence the development of timber NOT tools.
In addition to the development of an NOT method, the author has provided the first large-scale derivation of reference values for dynamic stiffness and other acoustic properties for 35 year old logs and beams of Sitka spruce in Scotland.

  • Type:


  • Date:

    30 June 2009

  • Publication Status:


  • Library of Congress:

    TH Building construction

  • Dewey Decimal Classification:

    674 Lumber processing, wood products & cork


MacKenzie, R. The non-destructive evaluation of Sitka spruce mechanical properties using acoustic methods. (Thesis). Edinburgh Napier University. Retrieved from



Scottish forestry; timber grading; Sitka spruce; sustainability; non-destructive test (NDT);

Monthly Views:

Available Documents