Download (PDF 192 KB): https://research.fs.usda.gov/download/treesearch/25911.pdf
Abstract
The objective of this research was to investigate the use of a stress wave technology to evaluate the structural quality of small-diameter timber before harvest. One hundred and ninety-two Douglas-fir and ponderosa pine trees were sampled from four stands in southwestern Oregon and subjected to stress wave tests in the field. Twelve of the trees, six Douglas-fir and six ponderosa pine, were harvested and sawn into logs and lumber. The mechanical properties of wood were then assessed by both stress wave and static bending techniques in the laboratory. Results of this study indicated a significant difference in stress wave time (SWT) between Douglas-fir and ponderosa pine trees and between two stands of each species. SWT of Douglas-fir trees increased slightly as tree diameter at breast height (DBH) increased; whereas, SWT of ponderosa pine trees decreased significantly as DBH increased. The statistical analysis also revealed good relationships between SWT of trees and modulus of elasticity (MOE) of logs and lumber produced from the trees as the two species were combined. However, the strength of the relationships was reduced within the species because of small sample size and narrow property range.
Keywords
Nondestructive testing,
small-diameter timber,
mechanical properties,
Douglas fir,
ponderosa pine,
value added,
stress waves,
bending,
elasticity,
wood quality,
smallwood,
small timbers,
utilization,
modulus of elasticity
Citation
Wang, Xiping; Ross, Robert J.; Punches, John; Barbour, R. James; Forsman, John W.; Erickson, John R. 2003. Evaluation of small-diameter timber for value-added manufacturing : a stress wave approach. Precision forestry : proceedings of the second International Precision Forestry Symposium. Seattle, WA : Institute of Forest Resources, College of Forest Resources, University of Washington, [2003]: pages 91-96.
