Abstract

Forest reclamation of disturbed land in mining areas in Southern Patagonia is a difficult challenge. Reclamation after coal surface mining can take many years, especially in areas where vegetation growth is limited by natural climate conditions like Chilean Southern Patagonia. Recommendations established by the forest reclamation approach include top soil removal and storage before mining and then replace it at the time of starting revegetation efforts. The objective of this study was to evaluate the effect of a reapplication of top soil on soil quality and revegetation success of Nothofagus pumilio. The study was conducted in Riesco island, Magallanes Region, Chile. Four different sites of 0.25 ha inside Mina Invierno compensation area were selected for the study. Topsoil was removed to a depth of 1.3 m and storage for six months before it was replaced into the same area. Four other grassland sites were selected close to the one where the soil was replaced. Following topsoil replacement, Nothofagus pumilio seedlings were planted in both conditions and measured for morphological and physiological parameters for two growing seasons. At the end of the second year, volunteer herbaceous vegetation was characterized and compared between the two sites. Composite soil samples were sampled and characterized for physical and chemical parameters at each site as well. Seedlings growth was twice as high and, survival was higher in the replaced mixed soil sites with 84% in comparison to the grassland sites that reached 55% and growth. Likewise physiological measures in tree seedlings, water holding capacity and penetration resistance were significantly better in replaced soil sites, but bulk density showed higher values on these sites in comparison to the grassland sites. Herbaceous composition was dominated for naturalized species with cover of 50% in replaced mixed soil and was different to grassland sites cover. Our results suggest that topsoil removal, when is properly handle, improve Nothofagus pumilio restoration efforts in Southern Patagonia.