Like all hygroscopic materials, the water content of wood varies depending on the relative humidity of the environment in which it is located. During cold weather, the raw material in the timber industry is generally stored either outdoors, or in unheated rooms with high relative humidity. In processing areas, the relative humidity is usually lower. The interior fibres of the wood react to this change when moving between areas and can crack, deform, or significantly change in size, all of which causes a deterioration in value and a problem with productivity throughout the industry.
Ideally, the wood should usually contain 11% moisture content, which requires a storage area with an RH of 60%. This can be hard to achieve as it is unusual for a ducted air conditioning facility to be installed in either processing or storage areas.