The site comprises three distincts experimental set-ups: (1) a long-term (>10 years) partial throughfall exclusion experiment replicated three times and crossed with a thinning (-30% basal area) experiment aimed at simulating long-term precipitation decrease in accordance with climate change scenario for the Mediterranean area (-30% of precipitation), (2) a total rainfall exclusion experiment using a mobile roof has been set up to simulate extreme drought events and modify precipitation seasonality, and (3) an eddy-covariance flux tower running continuously since 2001 to measure seasonal variations in ecosystem functioning and year-to-year flux responses to drought and climate.

The site of Montiers, localized at the boundaries between Meuse and Haute-Marne departments, North-East of France, has a large surface area (143 ha). It comprises two soil successions (toposequence) and the climate, stand conditions (age, species, forest management) are equivalent on all the surface of the site. The facility comprises three biogeochemical stations of 10 000 m2 each and one flux tower above forest canopy (45 m-high) settled along a soil succession representative of soils of the region. The three stations include four substations of which three are strongly equipped and one is free for future experimentations. Each equipped substation comprises lysimeters at different soil depths (litter, -10 cm, -30 cm, -60 cm and -90 cm; 3 replicates in general), tensio-lysimeters (-10 cm, -30 cm, -60 cm, -90 cm and -120 cm; 3 replicates in general) and temperature and moisture probes at different soil depths (-10 cm, -30 cm, -60 cm and -90 cm; 4 replicates), litterbags (6 replicates), stemflows (6 replicates), gutters (4 replicates). These stations allow to follow-up on the long term the flows of water, and major (Ca, Mg, K, Na, P, Fe, Mn, Si, Al, S, C, N) and trace (Cl, Se, B, I, Cs) elements between the different compartments (soil, tree, atmosphere) of a beech forest. Each station is settled on a different soil type, i.e., alocrisol, calci-brunisol, rendosol thus allowing to assess the impact of the soil type on biogeochemical cycles and on tree growth. The flux tower is equipped with a Eddy Covariance system (CO2, H2O, and sensible heat) and a complete set of sensors recording the aerial and edaphic meterological conditions, the phenology and the canopy status. The data from flux tower are available on demand. The forest mainly consists in a beech timber of about 50 years: dominant species and forestry in the region. The effect of the soil on the biogeochemical and biological functioning of this beech forest is dealt with a very integrated approach (ecophysiology, microbiology, soil science and biogeochemistry). In addition, the flux tower permits to measure, at various levels of the canopy and above, meteorological parameters (temperature, radiation, and precipitation), the gaseous exchanges and the particular deposits.