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Context

Forest ecosystems play an important role in global biogeochemical cycles and have also many other environmental contributions (air and water quality, carbon storage…). Sustainable forest management guarantees forest multi-functionality. Greater pressure is being placed on forest ecosystems due to the combined action of climate change and an intensification of forest exploitation to respond to the growing demand for wood products.
It is therefore important to assess the capacity of forest soils to maintain their functions, i.e., biomass production, soil/water quality, carbon storage, biodiversity, face to global changes, and to propose forestry practices adapted to soil properties. However, it is a complex task to assess the response of soils to global change and the implications such changes have for forest management. More fundamental research is thus required before a reliable evaluation of the major trends can be made.

Objectives

(i) To assess the influence of soil on the cycles of water, carbon, and major and trace elements, as well as on forest productivity (ii) to determine the interactions between these cycles, (iii) to better understand the contribution of some fluxes (i.e., dust…) to the biogeochemical cycles (iv) to determine the effect of biological activities on the cycles, and (v) to test the impact of global change on soil fertility and forest growth. It has been set out to answer the following questions: (i) To what extend soil properties influence water and nutrient cycles as well as tree growth and nutrition? (ii) What is the sensitivity of various soil types to global change and its impact on stand growth? (iii) Do trees develop adaptation strategies to balance unfavourable soil conditions thus maintaining high productivity potentials?

Site description:

The ecosystem research site of Montiers is located in Northeastern France in the Meuse department (48° 31' 54'' N, 5° 16' 08'' E). The forest of Montiers was chosen to support our research because it presents, on a restricted surface area with the same climate conditions, a great diversity of soils representative of the region, from acid and deep soils (alocrisol/brunisol) to calcic and superficial soils (rendisol), on which grows a mature and homogeneous beech forest stand (age, species, forest management). The local climate is semi-continental, characterized by cold winters and moderately hot and dry summers. The average annual temperature over the last ten years was 12.6°C with monthly averages from 4.4 to 21.2 °C (Météo-France). The yearly average precipitation over the last ten years is 1100 mm with monthly average of 100 mm. The geology consists of two overlapping soil parent materials, an underlying Tithonian limestone surmounted by detrital acidic Valanginian sediments. The forest humus form ranges from active to acidic mull. The forest population is dominated by a cluster of about 50-year-old beech (88%) mixed with other deciduous species.

Experimental design and monitoring:

The site comprises 3 biogeochemical stations developed on 3 soil types representative of the region: S1 station: alocrisol, S2 station: calci-brunisol, S3 station: rendisol, and a flux tower on the alocrisol. Each biogeochemical station with a surface area of 1ha comprises four substations of equivalent surface area (50m x 50m), 3 substations are instrumented to follow the cycles of water and elements, as well as tree growth (details in table below), and one substation is free for future experimentations. The parameters assessed for the initial site characterization as well as the equipments settled for the monitoring in the different biogeochemical stations (since 2012) and on the flux tower (since 2013) are presented in the table below.
Initial characterization of the site:
- Lichen and fungus surveys
- Soil description and analyses : from 9 pits (1 by sub-station) 81 auger soudings (9 by sub-station), quantification of fine roots
- Humus+small woods description, quantification, analysis from 81 points (9 by sub-station)
- Description, quantification and analysis of vegetation from  81 points (9 by sub-station)
- Stand : biomass and mineralomass evaluation for beech and maple trees

Permanent instrumentation Tower and biogeochemical stations (equipment by sub-station)
Climate: 3 rainwater collector above the canopy and 1 rainwater collector in a clearing, meteorological station on flux tower (45 m) close to station 1 : CO2, H2O, sensible heat, and soil heat fluxes, net global incident radiation, albedo, infrared radiation, incident and reflected/emitted components of shortwave and longwave radiation, direct/diffuse photosynthetically active radiation, vertical profile of relative humidity, temperature and wind (speed, direction), canopy temperature, atmospheric pressure, rainwater above and below the canopy, snow height, phenology
Soil moisture: groups of 4 TDR probes at different depths ; 12 hours timeframe
Soil temperature: groups of 3 probes at different depth; one-hour timeframe
Atmospheric deposits (solid and dissolved): 3 rainwater collectors
Pluviolessivates: 4 collectors settled radially under the forest cover; collect each 4 weeks
Stemflow: 6 collector (collars) settled on trees of differents diamters, collect each 4 weeks
Soil solutions: 4 at different depths; collect each four weeks.
3 sets of 8 fluteaux settled under the litter and at different depths; collect each four weeks.
Lysimeters settled at different depths; collect each four weeks.
Litter: 6 bags, collect in March, June, August, October and December.
Tree growth : manual dendrometer on 135 trees (all stem diameter); each four weeks during the vegetation period, since 2013. Automatic dendrometers on 24 beech trees (stem diameter > 13 cm); each hour since 2014.
One annuel measurement of stem diameter for each tree in November since 2009. One measurement of height for trees with a stem diameter > 13 cm ;  each 4 years since 2013.
Mineral content of Sun leaves once year (August) since 2011 (outside the stations)
LAI measurement since 2013

Running multidisciplinary projects on the network:

(i)    The biogeochemical cycles of water, carbon, major and trace elements on different types of soil. Scientific coordinator: M.-P. Turpault (INRA BEF)
(ii)    The gaseous exchanges between the atmosphere and the canopy of a mature beech grove. Scientific coordinator: B. Longdoz (INRA EEF)
(iii)    Impact of soil types on the diversity, function and functioning of the forest soil microbial communities. Scientific coordinator: S. Uroz (INRA IAM-BEF)
Valorization: 8 PhD, 2 post-doc, 12 degree reports, 31 conferences, 15 publications

Project investigators

Site: Turpault Marie-Pierre (INRA BEF), Galy Catherine (Andra), Biogeochemical stations: Turpault Marie-Pierre (INRA BEF) and Redon Paul-Olivier (Andra); Flux tower: Bernard Longdoz (INRA EEF) and  Conil  Sébastien (Andra). Contacts: marie-pierre.turpault@inra.fr
CONTACTS: name.surname@inra.fr

Contributors

L. Saint-André, S. Uroz,  B. Zeller, A. Legout, G. Van der Heijden (INRA BEF), N. Angeli (INRA EEF), M. Buée, A. Deveau  (INRA IAM), S. Conil, P.-O. Redon, A. Albrecht, Y. Thiry (Andra), L. Bernedetti, D. Bourles (Univ. Aix-Marseille). M. Bueno, F. Pannier, I. Le Hécho (Univ. Pau), D. Boulaud, Pourcelot L.  (IRSND), D. Lemarchand, S. Rihs, F. Chabaux (LHYGES, Strasbourg) A. Besserer (Univ. Lorraine (ENSTIB/LERMAB), P. Leblond, B. Aigle, C. Bontemps (Univ. Lorraine, DynaMIc), A. Cebron (Univ.  Lorraine, Liec), C. Hissler (C.R.P. G. Lippmann, Luxembourg), Y. Honda (Univ. Tsukuba, Japon).

Funding: