Evaluating warp from three sawing processes including saw-dry-rip to produce aspen structural lumber

This study compared three sawing methods for manufacturing structural lumber from trembling aspen (Populus tremuloides Michx.). Ninety logs were selected and divided into 3 comparable groups of 30 logs each. The first group was sawn “conventionally,” the second “around,” and the third one was sawn according to a method called “Saw-Dry-Rip” (SDR). The three groups were conventionally kiln-dried with the same schedule and planed following drying. The three sawing methods were evaluated with respect to warp (crook, bow, and twist) at every stage of the process. The major results are that crook averaged 1.5 mm for the SDR method, 5.6 mm for the around process, and 8.7 mm for conventional sawing. An analysis of variance indicated that these differences were statistically significant. The average gross yield was comparable for each of the three methods. In a complementary study, SDR specimens showed significantly lower modulus of rupture, modulus of elasticity, and ovendry specific gravity than the other groups.

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