Thirty years of research on soil quality in forest systems under Mediterranean conditions. Trends and future

This paper presents an overview of the studies carried out between the mid-1980s and 2014 in Portugal, regarding the evaluation of soil quality within intensively managed forest systems. These studies show that the degradation of soil quality in such systems is mostly associated with the land, soil and harvest residue management schemes. Also, it was concluded that experimental results showing the short-term (one rotation scale) effects are useful for identifying the most appropriate land and residue management systems for maintaining the soil quality and thus forestry productivity and sustainability. However, these studies do not take into account all the risks and threats regarding soil degradation within the forestry activity at the land unit scale. Therefore it is necessary, on one hand, to develop long term experimental and risk assessment systems and, on the other hand, to delineate and implement soil quality monitoring systems that control soil degradation (e.g. erosion, compaction, nutrient and carbon losses) at the forest unit management scale