Wood hygroscopicity is the ability to exchange water vapour between the wood and the surrounding air in the sorption (assimilation) process. The wood either releases the excess moisture or absorbs it from the environment. Wood is characterised by its own humidity and tries to maintain its level in relation to the humidity of the surrounding air. This relationship is called the hygroscopic balance of wood and it depends on the relative air humidity and temperature.
Wooden items placed in rooms seek balance, and are dependent on the environmental conditions. Changing the climatic condition of the environment causes undesirable stresses in the wood structure, which translate into deformations. Consequently, they may lead to a permanent mechanical damage and destruction of wooden objects.
In order to prevent the phenomenon of wood damage, it is necessary to provide it with comfortable climatic conditions. For sculptures made of wood, the range of the relative air humidity is within the 55 +/- 5%, and temperature in the range of 14-18° C. In order to ensure the desired parameters, professional climatic devices are used. Such as, humidifiers in winter, and dehumidifiers in summer.
An example of this device that cultivates desired climatic conditions is presented in the photograph.