Yield of Yellow-Poplar Structural Dimension from Low-Grade Saw Logs

8/4 lumber was live-sawed from the low-grade portions of 102 yellow-poplar logs. Only 20 percent graded No. 1 Common and Better and 80 percent No. 2B and Better as factory lumber. This was converted to 2 by 4s, dried, and graded by ALS softwood rules as structural dimension. Crook was the big problem. At both 12 and 19 percent MC, more than half of the pieces crooked in excess of 1/4 inch, the maximum allowed for Stud grade by softwood rules. A considerable part of the crook occurred before seasoning as a result of the release of longitudinal growth stresses. It was strongly correlated with growth ring direction, increasing from a minimum in flatsawed material to a minimum in quartersawed material. Considering only knots, 90 percent of the pieces would have made Stud grade. If yellow-poplar is to be considered for such uses as structural framing, research is needed to find a means of reducing crook, possibly during seasoning.

You must be logged in to download any documents. Please login (login accounts are free) or learn how to Become a Member