Oak is a very common tree in Europe. A sacred tree for the Celts, it personified the strength that lies within us. To designate the northern half of France, the Romans used the term "Gaule chevelue" (Gallia comata), referencing oaks, because this territory was largely forested with oak trees. A majestic tree, the oak defies the centuries; it can become a thousand years old. Although it likes slightly damp soils, it also adapts very well to dry, chalky soils. Two species are particularly at ease under the skies of Haute-Provence. The Pubescent Oak (Quercus pubescens), or Downy Oak, grows at an altitude of between 300 and 1200 metres. Its leaves turn yellow in autumn and fall off at the end of winter. The Holm Aak (Quercus ilex), an evergreen oak, is often found on the slopes with juniper trees. It grows in areas of up to 1,300 metres altitude.

The first reference-data and reference-graphs in dendrochronology (the scientific method of tree-ring dating) was established from the oak forests of Northern Europe. In this way, time was traced back 6,000 years.

Here, the pubescent oak forest was the victim of a major fire in the first half of the 20th century. Some trees survived, but many of the centuries-old oaks burned down. Young trees have naturally regenerated the oak forest.