Bend, Break, Evaluate

By: Vanessa Beeson

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Posted: 2/5/2020

Bend, Break, Evaluate Photo By: Submitted

Timber is a multibillion dollar industry. Forestry is the number two leading commodity in the state of Mississippi generating nearly $1.2 billion in timber harvesting last year alone. Scientists in the Forest and Wildlife Research Center have completed a five year study to help increase the value of southern forests.

"Wood is the most important source of housing in the U.S. and the U.S. South is the most viable and sustainable, and largest wood basket in any developed nation. We have a responsibility to make sure we use this resource wisely and promote its ongoing use in perpetuity. We want wood structures to be engineered correctly and the materials therein to be properly and appropriately used. By developing better engineering valuation technology for lumber and building products, we help assure that just the right amount, or an optimal amount, of wood is used in construction," said Dr. Rubin Shmulsky, professor and head of the Department of Sustainable Bioproducts.

The two part study, which involved several faculty and dozens of graduate students, included the evaluation of approximately 300 pieces and then expanded to another 2000 pieces of lumber acquired from 10 southern states from Virginia to Texas over the course of five years. The team conducted several methods of nondestructive testing to evaluate the accuracy and reliability of those methods, which are currently and widely used for grading and testing structural lumber.

Researchers evaluated the specimens nondestructively with continuous proof bending, transverse vibration, and longitudinal stress wave methods in sequence. Specifically, the team was interested in the linear relationship of the modulus of elasticity, or MOE, and the modulus of rupture, or MOR, finding that MOE can be used to predict MOR. Once that data was collected, the team broke the boards, destructively evaluating them by fourpoint static bending tests to obtain static MOE and MOR values.

Shmulsky said the team statistically compared the results in an effort to find ways and means of increasing board performance and economic value.

"We consistently find that there are achievable ways to better evaluate the economic value of lumber. This in turn can be extended to forests. The more we know about the value of the lumber coming from the forest, the more value forest managers and timberland owners can achieve from their land. Also, they can make better informed decisions about their forest management and operations," Shmulsky said.

Dr. Dan Seale, Warren S. Thompson Professor of Wood Science and Technology, served as co-principal investigator on the project. He said the team has wrapped up research on bending properties, which apply to the beams, girders, joists, rafters, and stringers in a building and will get to work testing tension, which is important for wood trusses. Seale said the research was like trying to solve a big puzzle and one of his favorite aspects of the work is watching graduate students figure out their individual roles in solving that big picture problem.

"I love to see a graduate student finally put all of the pieces together. Each of them works on their own little piece and when we are all working together, there's inevitably a moment when each of them realizes their one piece is part of a really big pie and that all the pieces need to fit together," Seale said.

He is also proud of Smart Thumper, an app that was released in 2018, born out of this research project. Seale said he's also proud of the potential impact the research can have on the industry as a whole.

"We have millions of acres of forests that need to have the best value and economic opportunity possible. We know to keep land in forests instead of having it converted to agriculture or other uses, the forests need to have as much value as possible," Seale said. "By better evaluating how stiff and strong every single stick of wood is then ultimately those trees become worth more money and landowners will keep that land in forests and replant and grow it for the future."

The following partners have contributed to the research through funding or other support: USDA Agricultural Research Service, USDA Forest Products Laboratory, Mississippi Lumber Manufacturers Association, Southern Pine Inspection Bureau, Timber Products Inspection Agency, Southern Pressure Treaters' Association, Mississippi Forestry Association, American Wood Protection Association, Southern Forest Products Association, Southeastern Lumber Manufacturers Association, Stairbuilders and Manufacturers Association, Southwestern Hardwood Manufacturers Club, and mills across the Southeastern U.S. Funding is also provided by the Forest and Wildlife Research Center.

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