lumber, collective term for harvested wood, whether dig logs, heavy timbers, or members utilized in light-frame construction. Lumber is assessed as hardwood or softwood. The term often refers specifically to the products derived from logs during a sawmill. Conversion of logs to sawed lumber involves debarking, sawing into boards or slabs, resawing into thinner boards of varying sizes, edging, crosscutting to face the ends and take away defects, grading consistent with strength and appearance, and drying within the outdoors or in kilns. Drying below the fiber-saturation point leads to shrinkage and usually greater strength, stiffness, and density and better prepares the wood for finishing. Preservatives are often applied to guard the wood from deterioration and decay.