Study area - The Picardy district
The Picardy district (Pic.) is a large region of clayish soils, sand, silts and loess, deposited over chalk of the upper Cretaceous. The climate is rather oceanic and the contrasts are small, with some differences between the more coastal west and the more continental east. Despite the intensive exploitation, several large forests in the western part still show a remarkable epiphytic lichen flora with many oceanic species. Fagus is maintained through adequate forestry practice, but most of the woodland belongs to the neutrophilous Quercus-Fraxinus-Carpinus community, which also occurs in the Boulogne district on the drier soils. With the exception of the most western part, bordered by the Maritime and the Boulogne districts, the lichen flora of the Picardy district is hardly known.