Spécificités des sols volcaniques du Massif Central: Bénéfices et contraintes pour la gestion forestière

Abstract

Volcanic soils cover only 1-2 % of the world's land surface but nearly 7 % of the Massif Central area, France, with mostly permanent grassland (80 %) but also forest (20 %). Volcanic soils are characterized by distinctive mineralogical, chemical and physical properties, collectively termed andic properties, which separate volcanic soils from other types of soils, making them particularly fertile. These andic properties may be beneficial for tree growth but also partly induce dieback in softwood stands, particularly after long periods of drought, associated with both potassium deficiency and the difficulty in rehumidifying the dried-out and hence hydrophobic topsoils. This study reviews and reports different degrees of forest decline in connection with soil properties (hydrological properties, mineral deficiency, aluminium toxicity), and their dynamics. Finally, the productivity of Norway spruce is highly dependent on the particular characteristics of each type of volcanic soil.