Forest die-off reduces soil C and N content and increases C stability in a Mediterranean woodland

Drought-induced forest die-off is occurring worldwide and is projected to increase in coming decades. However, if and to what extent this phenomenon affects the content of carbon (C) and nitrogen (N) in soils as well as its stability is far from clear. In a Mediterranean oak forest, we found that forest die-off negatively affected soil C and N contents, and positively affected C stability. We also found that the effect of forest die-off on soil C and N content was more pronounced at the 0–5 cm than at the 5–10 cm soil layer, while the opposite was found for soil C stability. Our results highlight the importance of considering both, soil organic matter quantity and stability, along the soil profile to fully understand the effects of environmental changes on the global C and N cycle.A.R. was supported by the Spanish National Research Council (CSIC) in the JAE-doc modality co-financed by the European Social Fund (ESF). J.D. and A.R. acknowledge support from the Fundação para Ciência e Tecnologia (IF/00950/2014 and SFRH/BDP/108913/2015, respectively), as well as from the FEDER, within the PT2020 Partnership Agreement and COMPETE 2020 (UID/BIA/04004/2019). T.C. was supported by the “Departments of Excellence-2018” Program of the Italian Ministry of Education, University and Research, DIBAF-Department of University of Tuscia, Project “Landscape 4.0 – food, wellbeing and environment”