A Comparison of Two Non-Destructive Techniques for Determining the Modulus of Elasticity of Small-Diameter Roundwood Thesis uri icon



  • Thesis (M.S., Natural Resources) -- University of Idaho, 2017 | Because small-diameter trees are more important commercially than ever before, deriving the greatest value possible from those logs is necessary. In an effort to promote a simple, low-cost method for determining stiffness in small-diameter roundwood, we tested 50 logs (both 4-inch and 6-inch) of varying ages and species using two non-destructive evaluation techniques for grading logs—stress-wave velocity (in conjunction with density) to determine dynamic modulus of elasticity (MOE) and mid-point loading to measure static MOE. We also looked at a sample set of 90 lodgepole pine logs from a previous study to explore whether or not the MOE values taken at 45° increments fit a sine wave. Both SWV and mid-point loading gave us MOE results that correlated well with MOE values derived from third-point bending. The analysis of the 90-log data set showed more than half of the logs fitting a sine wave at a 95% confidence level.

publication date

  • June 1, 2017