Sustainable development is a goal to be reached in ecosystems to ensure good management that can lead to a healthy and productive environment. Natural forests play a central role in the state of environment, and knowledge on biological criteria that conduct the dynamics of them is needed to understand the main points to take into account in order to carry out this good management. Since the last few decades, marked land use changes have taken place throughout the Mediterranean region. These changes have a great impact on plant diversity of which variations can affect in return ecosystem functioning. The approach involves rigorous scientific experimentation, leading to detailed of the policy socio-economic implications of the research findings and followed by dissemination of information to policy makers and end-users. A multidisciplinary consortium will cover many aspects of biogeochemical cycles in forest ecosystem including a strong emphasis on the soil community. The considered methodologies are productivity, litter production, litter decomposition, nutrient balance, physiology, seasonal variation of canopy leaf biomass, nutrient translocation and nutrient use efficiency.