The Strengbach catchment is an experimental forest monitored since 1986 for hydrological, geochemical and meteorological data. This 80ha surface area catchment is located in the Vosges massif with a temperate oceanic mountainous climate, on granitic bedrock. All reservoirs involved in the biogeochemical cycling are studied. Wet atmospheric depositions (rain, snow), dry atmospheric particles (aerosols), all stream and spring waters, groundwaters (piezometer), soil profiles, saprolite and bedrock, vegetation (roots, wood, bark, leaves, litter). The Strengbach experimental catchment represents a natural laboratory to study and understand the weathering processes and the biogeochemical cycles at the scale of a forested ecosystem.