A historical and natural heritage

Located in the southern Morvan, mont Beuvray is a 950-hectare public forest massif that reflects the broader forest dynamics of the region. At its summit stand the remains of the capital city of one of the most powerful Gallic peoples of the 2nd century BC. Mont Beuvray thus combines a remarkable concentration of cultural values (classified site, historical monument), social values (around 100 000 visitors each year), and natural values (Natura 2000 site, remarkable tree heritage).

A mid-mountain climate

The Morvan massif has an oceanic mid-mountain climate characterized by long, harsh winters, late springs, and hot but short summers. Precipitation is abundant and varies significantly from year to year, with an annual average of 1,252 mm over the period 1991–2020, enhanced by orographic effects and exposure to prevailing southwesterly winds. The massif records a mean annual temperature of 10.5 °C and a thermal amplitude exceeding 20 °C, which gives it continental features, particularly in terms of the frequency of frost events.

Hydrogeological context

Mont Beuvray is composed of a complex of ancient volcanic and sedimentary rocks. At the surface, these rocks are weathered into relatively permeable sandy and clayey regolith. They overlie a compact and impermeable bedrock. Precipitation is the sole source of aquifer recharge: it infiltrates the weathered zone where it accumulates before percolating deeper through the fissures and fractures of the rock. This hydrogeological functioning accounts for the numerous springs and the sustained recharge of the massif’s hydrographic network.

The Morvan: a massif particularly vulnerable to climate change

Over the past fifty years, the Morvan has experienced a faster rate of warming than the adjacent lowlands, thereby exacerbating water stress and undermining the resilience of forest ecosystems. Conifer species introduced during the 20th century, such as spruce and silver fir, have been increasingly affected by recurrent droughts, pest outbreaks, and large-scale clear-cutting. Native broadleaved species are likewise exhibiting signs of decline. These ecological transformations are reshaping the physiognomy of the massif and contributing to the emergence of heightened socio-ecological tensions between forestry stakeholders and local communities.