Post sorting of hem-fir : a mill study

In some species and species groups, many pieces with high post-drying moisture content (wet pieces) are present after kiln-drying of lumber. Often, they cannot be economically eliminated by equalization, especially for dimension lumber for which a 15 percent average final moisture content is desirable. A mill study was conducted in which lumber (2- by 8-in. hem-fir) was sorted after being dried ; any wet pieces were redried in a separate kiln. The results indicate that 14 percent less total kiln time is required at a given production rate if 20 percent of the pieces are redried. Kiln-operation expenses are reduced by $4.56 per thousand board feet (MBF). Average lumber value is increased by $9.40/MBF because of reduced overdrying. Additional material-handling costs were $1.95/MBF. Gross profit margin increased by $12.01/MBF. The payback period for the additional equipment installed to sort and restack wet pieces was 6 months.