The numerous functions of protection, social welfare and production that the wood has to carry out must be kept through a cautious managing of the forest resource. The managing has to be sustainable, that is to say, the availability of the forest resource must be guaranteed for future generations too, without giving up aims of socio-economical promotion. For this reason, it is necessary to establish what kind of works have to be carried out in our woods, in order to adapt the use and the interventions to the vital natural processes, to favour the stability and quality of stands in time and space.