Abstract: A dry kiln for wood products that has sample tunnels mounted strategic to each of the charges (stacks) of wood products that are to be dried. A board sample is mounted in the tunnel that is representative of the charges to be dried. A sensing device mounted in the tunnel and supporting the board sample continuously monitors the weight of the board sample and inputs the information to a controller. The moisture content of the board sample at any time during the cycle is ascertained by weight. The board sample in the tunnel is subjected to the same drying conditions as the charge and therefore the moisture content of the charge will be the same as the board sample. The continuous weight monitoring of the board sample is accordingly used by the controller to control the dry cycle.