What is the main cause of forest degradation?

degradation: this does not involve a reduction of the forest area, but rather a quality decrease in its condition, this being related to one or a number of different forest ecosystem components (vegetation layer, fauna, soil, ...), to the interactions between these components, and more generally to its functioning. The estimation of degradation can be hampered by a number of difficulties that are notably caused by:

• the different choices of the initial state of reference: "climax" or its numerous substitutes, the forest condition which corresponds to the silvicultural model that was adopted, ...;
• the criteria (with their indicators) one favours: health and vitality, species diversity, the production capacity of market or non-market goods and services;
• depending upon whether we limit ourselves to the present date, or whether we consider that the present state is only transitory and leads to a satisfactory, or even improved, later state