Degrade (Lumber)
Degrade is the loss of lumber value or grade due to defects that develop during drying, storage, or handling. Common forms of degrade include checking, splitting, warping, staining, and insect damage. Minimizing degrade is a primary goal of proper kiln drying and lumber storage practices.
In-Depth Explanation
Degrade represents the economic loss between the potential value of lumber at its highest achievable grade and its actual value after defects have developed. Every stage of the lumber production chain presents degrade risks: in the log yard, fungal stain and end checking can begin within hours of felling; during sawing, poor cutting decisions can create unnecessary defects; during drying, inadequate kiln schedules cause warping, checking, case hardening, and honeycombing; and during storage and transport, poor stacking, moisture re-absorption, mechanical damage, and insect attack can further reduce value. The financial impact of degrade is significant — a board that could grade FAS (the highest hardwood grade) but drops to No. 1 Common due to drying defects may lose 30-50 percent of its value. Sawmill operations measure and track degrade percentages as a key performance indicator. Best practices for minimizing degrade include prompt end-sealing of logs and freshly sawn lumber, anti-stain chemical treatments, carefully scheduled kiln drying, proper stacking with aligned stickers, covered storage, and careful handling during loading and transport.
Usage Example
The kiln operator reduced degrade from 12 percent to 4 percent by slowing the drying schedule for the thick white oak, saving the mill thousands per load.