Badlands forest restoration in Central Spain after 50 years under a Mediterranean-continental climate

Abstract

This study shows the results of a badlands restoration carried out 50 years ago in Central Spain in terms of soil evolution, vegetation and hydrological characteristics. Although gully restoration is frequently employed to recover degraded soils and reduce sediment yield to rivers and reservoirs, analysis of the evolution of this type of action after a long period of time is not so commonplace. Moreover, this study focuses on a unique area under a Mediterranean-continental climate, with granite and sandy soils. Restoration works consisted in the construction of at least 123 check dams and the reforestation of more than 730ha, with 2700 treesha−1. Nowadays, the soils have begun to regenerate. Litter thickness and soil humus is 3.7cm under the pine-forest, while it is null in the degraded soil. Forest soil has a higher resistance to penetration and higher K and P content. However, there are no significant differences in the% OM, in the content of Ca, Mg, Na and N, or in the steady-state infiltration rate, possibly because of the influence of soil texture. These results show that much more time is needed for soil evolution. As a conclusion, however, restoration works did improve forest cover and some physical and chemical soil properties as well as slowing down soil erosion and sediment production. Suitable silviculture and land management of the current pine forest will improve soil conditions and serve to recover the ancient native oak forest that grew before the intense historic degradation.