Como humanidad estamos inmersos en una red sistémica de interacciones ambientales y sujetos a un contrato ambiental implícito con la biósfera en el cual se nos permite estar vivos a cambio de mantener las condiciones que permiten la vida. Pero si alteramos significativamente dicha red de relaciones biosféricas, el contrato se rompe y nuestra supervivencia entra en riesgo. La cultura del desarrollo tecnológico y el modelo productivo global han llegado a un punto en que se hace insostenible el actual crecimiento económico para la manutención de umbrales medioambientales planetarios seguros para el devenir de la humanidad. Este paradigma económico se apoya en un contrato social de valores antropocéntricos que considera a la Naturaleza como un mercado de recursos a libre disposición del ser humano. Sin embargo, este modelo contractual nos está llevando como sociedad al colapso inminente debido al desequilibrio ecosistémico causado por el ser humano. De aquí la necesidad de construir un contrato que trascienda a la sociedad y reincorpore a la Naturaleza para así recuperar la armonía entre los seres humanos y nuestro entorno, un nuevo acuerdo que trascienda de una perspectiva antropocéntrica a una ecocéntrica.

Water supply is one of the largest and most valued ecosystem services from forests. This paper presents a systematization of scientific studies about the effects generated by exotic fast-growing forest plantations of Pinus radiata and of Eucalyptus spp. on water yield in south-central Chilean watersheds (33 - 41º S), at different spatial and temporal scales. We compiled scientific studies that have at least one year of observations on large catchments, small catchments and experimental plots. Studies in experimental plots of Pinus radiata plantations showed that annual evapotranspiration increased from south (41° S) to north (33° S), while in this northernmost site almost the entire incoming precipitation was evapotranspired, and the percolated water was negligible. Studies of water balance in small catchments documented a negative linear relationship between total streamflow and forest plantations coverage. Catchments with forest coverage of Pinus or Eucalyptus spp. stored less water than catchments with mixed species, mainly due to high interception loss, more net evapotranspiration and reduced percolation. Forest plantation management can alter the accumulation of water in the catchment (soil and groundwater) and forest cover is the fundamental factor in the dynamics water accumulation. Long-term studies focused on changes in forest coverage from native to plantation forests in large catchments located in the Mediterranean area (33 - 38º S) of Chile showed a sustained reduction in water yield, especially during summertime.

Water supply is one of the largest and most valued ecosystem services from forests. This paper presents a systematization of scientific studies about the effects generated by exotic fast-growing forest plantations of Pinus radiata D. Don and of Eucalyptus spp. on water yield in south-central Chilean watersheds (33 - 41ºS), at different spatial and temporal scales. We compiled scientific studies that have at least one year of observations on small and large catchments and experimental plots. Studies in experimental plots of Pinus radiata plantations show that annual evapotranspiration increase from south (40° S) to north (33° S), while in this northernmost site almost the entire incoming precipitation was evapotranspired, and the percolated water was negligible. Studies of water balance in small catchments document a negative linear relationship between total streamflow and forest plantations coverage. Catchments with forest coverage of Pinus or Eucalyptus spp. store less water than catchments with mixed species, mainly due to high interception loss, more net evapotranspiration and reduced percolation. Forest management can alter the accumulation of water in the catchment (soil and groundwater) and forest cover is the fundamental factor in the dynamics water accumulation. Long-term studies focused on changes in forest coverage from native forest to forest plantations in large catchments located in the Mediterranean area (33 - 38º S) of Chile show a sustained reduction in water yield, especially during summertime.