The Canadian Lumber Standards Accreditation Board (CLSAB) monitors the quality of Canada's lumber grading and identification system.Attempts to maintain lumber quality over time have been challenged by historical changes in the timber resources of the United States?from the slow-growing virgin forests common over a century ago to the fast-growing plantations now common in today's commercial forests. The National Lumber Grades Authority (NLGA) is responsible for writing, interpreting and maintaining Canadian lumber grading rules and standards. Grades standardize the quality of lumber at different levels and are based on moisture content, size and manufacture at the time of grading, shipping and unloading by the buyer.
The result is a more precise understanding of the strength of each piece of lumber than is possible with visually graded lumber, which allows designers to use full-design strength and avoid overbuilding. Machine grading measures a characteristic such as stiffness or density that correlates with the structural properties of interest, such as bending strength.
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