Fresh wood contains a lot of water, which will evaporate in a specific environment. The natural evaporation of water will lead to wood shrinkage, cracking, bending deformation, mildew and other defects, affecting the quality of wood products. Therefore, wood must be forced (controlled) drying before being made into wood products. This is an important technical measure to make rational use of wood and increase the value of wood. It is also an indispensable primary process in the production of wood products.
But doesn't it mean that the drier the wood, the better? Many people have misunderstandings about this.
Under certain environment, after a period of time, the moisture content of wood will tend to an equilibrium value, which is called the equilibrium moisture content of the environment. When the moisture content of a piece of wood is higher than the equilibrium moisture content of the environment, the wood will shrink and absorb moisture, otherwise it will expand. For example, the equilibrium moisture content in Beijing is 11.4%, and that in Guangzhou is 15.1%. If the wood dried to 11% is put in Beijing, it is suitable, but if the wood is put in Guangzhou, it will expand and deform.
Therefore, wood drying should be handled properly according to local conditions, not as dry as possible.