ABSTRACT
The Massif Central is an upland area of igneous origin in southern France (Figure 16.1) with a mean elevation of 800 m, from 300 m in the Limagne plain to 1886 m in the Sancy Mountains and covers about 70,000 km2 (12.7% of France). Only the higher elevations will be considered here, as the low fertile plains are farmed (Figure 16.2). The climate is semicontinental, with low winter temperatures (≥−20°C), late spring frosts (until June), and high summer temperatures (≤30°C). A striking feature of the climate is the high amplitude of daily temperature variation, sometimes more than 25°C. Temperatures vary with elevation, about −0.6°C per +100 m elevation (Guitton 1986). Rainfall is about 800 mm per year but varies widely with exposure, from less than 600 mm in the rain shadow of hills to more than 1500 mm in the west slopes of the mountains. Rainfall is fairly evenly distributed throughout the year (Figure 16.3), especially in areas beneting from oceanic inuences, but summer droughts occur about one year in every ve (Balandier et al. 2003a).
