By the end of the 19th century, erosion had reached catastrophic levels in the Southern Alps. The cause was the deforestation that had been going on for centuries, leaving the exposed soil to drain away.

Several laws were successively voted which gave the State the means to intervene, sometimes against the will of the local inhabitants who were unaware of the reality of the issues and dire consequences.

State-run Forestry Centres were built to accomodate the Water & Forestry staff and to prepare for future planting, thanks to the tree-nurseries that were established around the Forestry Centres.

Numerous experiments were conducted to select the Austrian black pine tree as the preferred species for reforestation.

However the woodlanders liked to shade their houses with majestic and decorative exotic species such as redwoods and cedars.

A little to the north of La Motte du Caire, the Saignon valley is a good example of ongoing research into the evolution of these man-made, man-managed forests. There is also an educational-trail with explanatory signs and information.

Within the Haute-Provence UNESCO Global Geopark, other sites evoke these issues of reforestation and erosion: the forest park of Brusquet, the Demontzey park at the Col du Labouret mountain-pass and various forestry techniques and projects in the Draix valley.