Bioproducts Testing and Evaluation Stories
Researchers in MSU’s Forest and Wildlife Research Center hope to untangle how knots—remnants of where branches grew while the tree was alive—affect the stiffness and strength of this important commodity. The team set out to investigate the role multiple knots in proximity play on affecting lumber stiffness and strength to increase the value of southern pine. In a series of studies spanning several years, Drs. Rubin Shmulsky, professor and head; Dan Seale, professor; and Jason Street, associate professor, led a team of graduate students as they analyzed southern pine boards produced at a local Mississippi sawmill to determine if small clusters of knots impacted lumber stiffness and strength. The research’s goal is to find a more accurate way of measuring the mechanical properties of lumber so that a more particular strength rating can be associated with each piece produced.
This research was funded by the Forest and Wildlife Research Center and the USDA Forest Service Forest Products Laboratory in Madison, Wisconsin.
Finding a Better Model
In 2013, after several years of testing and reassessment, the design values for southern pine dimension lumber were adjusted, which affects the value of pine logs on timberland. Dr. Frank Owens, a sustainable bioproducts assistant professor, began working on a project with the help of his doctoral student to evaluate various statistical models to determine if, perhaps, there was a better model for lumber standards. The team has tested strength and stiffness of 2,000 specimens of mill-run 2x4 kiln dried softwood lumber from six U.S. sawmills. They have tested southern yellow pine from four Mississippi mills, and red pine and spruce from two northern mills. This research will ultimately provide a more accurate assessment of lumber strength and stiffness values brings about better stumpage prices and higher sustainability.
New App Measures Wood Stiffness
Forest and Wildlife Research Center researchers, Drs. Dan Seale and Frederico Franca, developed an app that allows lumber buyers to conduct additional testing to determine where a piece of lumber sits within a determined grading scale. The app, Smart Thumper, available on Apple and android devices, uses vibrations or soundwaves to determine the stiffness of the lumber. The app was constructed to benefit the do-it-yourself market and anyone that needs to identify what piece of lumber is stronger or weaker than the other, which cannot be accomplished with a visual inspection. The app can help further evaluate lumber within established grades, potentially optimizing the longevity and cost efficiency of wood structures by selecting stiffer pieces for situations that demand high performance.