The wood is a material of organic origin, and such as is more subject to a number of degrading processes that may lead to considerable variations in its appearance and its mechanical, chemical and physical properties.

In the case of wooden structures the processes of alteration may involve in to severe damage for the structural level: thus, it is very important not only to diagnose accurately the conservation status of the material, but also to identify the environmental and biological risk factors that may lead to deterioration.

The first step is the identification of macroscopic species of wood that make up the manufacture; knowing that, it can then make the determination of the durability of the material, identifying and assessing technological defects and alterations, determination of pathology and biological classes of risk.
For the evaluation of the state of conservation of the material, other investigations are carried out, such as penetrometric and resistograph method tests, Pressler auger, and endoscopy. The dendrochronological examination allows finally to give in many cases a certain date to the wood used.