Aboveground nutrient cycling in temperate forest ecosystems of southern Chile

Forest ecosystems have important ecological, economic, and social values, but are subject to varying ecosystem pressures, including enhanced atmospheric nitrogen deposition. This paper quantifies nutrient fluxes in varying forest types in southern Chile in order to evaluate external and internal nutrient cycling within ecosystems, with a focus on the aboveground compartment. The objectives were to establish baseline data for pristine forest ecosystems and to study differences between forest types. Measurements were performed in four stands in the lower Andean mountain range (San Pablo de Tregua), two stands in the Central Depression (Paillaco) and six catchments in the Coastal mountain range (40°S). External nutrient inputs and losses were assessed by analyzing precipitation, throughfall, stemflow, soil percolation, and streamflow. Internal aboveground nutrient cycling was quantified by means of a canopy budget model, litterfall collection, and a litterbag decomposition experiment. Although temperate forests in southern Chile still represent a unique opportunity to study pristine ecosystems, measurements of water and ion fluxes indicate that forests in the central depression are exposed to enhanced external nitrogen inputs