Despite its Latin name, Quercus robur is less resistant to drought than its cousin the sessile oak, making it both more valuable and more threatened by global warming.
A widespread species in Eurasia, the common oak adapts very well to oceanic, sub-oceanic and moderate to humid continental climates. Together with the sessile oak, it is the main economic species. With 4.5 million hectares of oak forests, France has almost 40% of the total area of oak trees in Europe. It is the largest producer of oak in Europe and the second largest in the world, after the United States. Oak is the French species par excellence. A pioneer to post-pioneer species, it develops on a variety of substrates, clay, silt, sand and peat. It develops well on mesophilic soils that are neither dry nor too wet, and mesophygrophilic (cool and wet). During the growing season, the common oak needs more water than the sessile oak, which is why it is well adapted to certain regions (Brittany, Mayenne, Auvergne) where rainfall is regular and droughts rare. As an adult, the common oak can withstand flooding, as can its acorn, which is not the case for the sessile oak.
Quercus robur, also known as the common oak, is a forest species endemic to our temperate climates and is very common in France, although it is less common in the Mediterranean regions. This deciduous species is very similar to the sessile or holm oak and differs from it mainly in its leaves and buds. Whereas the sessile oak has a bud sitting directly on the branch, the bud of the common oak is carried by a long stalk. Its acorns are also grouped together and its leaves, which are rounder than those of the sessile oak, have two auricles at the base of the blade. It grows to an average height of 25 to 35 metres when fully grown, and some specimens can reach 40 metres. Its dimensions can be particularly imposing when it grows in isolation from its congeners, with a trunk of up to 5 metres in circumference. It can easily live up to 500 years, sometimes reaching a thousand years or more. It can grow very straight, but its crown is irregular because its large horizontal branches are gnarled and its foliage is dense, but pierced by clearings. Its grey-brown bark is smooth and shiny in young trees up to 20-30 years of age, then cracks and cracks deeply and becomes thicker and darker with age. Its buds are stockier and more ovoid than those of the sessile oak, just as its leaves are less pointed than those of its cousin. The petioles are also shorter than those of the sessile oak. This monoecious species flowers from April to May, before foliage sets. It bears fruit every two or three years, starting in its sixtieth year.
The common oak thrives better in cool, wet areas than in dry, sunny ones. What may have been a strength historically during cooling periods becomes a weakness in times of global warming and increasing dryness. Thus, the common oak is less adapted to Mediterranean and continental regions than the sessile oak. It tolerates both acidic and calcareous soils and prefers deep, rich soils with a good water supply. It is essentially a tree of the plains and hills or low mountains. The oak is hardly ever found above 1300 metres in altitude.
The wood of the common oak is one of the most sought-after, along with that of the sessile oak, which cannot be distinguished by the naked eye. It is an excellent wood for carpentry and construction, and was used to build the forest of Notre-Dame de Paris, which will be used again to repair its spire and framework. It is also much sought after for cooperage, particularly for wine and cognac. In this respect, the common and sessile oaks of France are exported throughout the world. Without them, wine would not be as we know it. It is still used in marquetry, parquetry, cabinet making, slicing, carving, and for the manufacture of sleepers and poles. When the logs are of lesser quality (twisted, gnarled, etc.), it makes excellent firewood or can be used to make paper pulp (this is particularly true of wood taken during thinning operations). Finally, its bark provides valuable tannins and has long been used to tan leather.
King of our forests, once venerated by our ancestors the Gauls and Greeks, but also the Romans and Germans, it is the tree of our regions par excellence. Slow to grow, robust, vigorous, solid and long-lived, it symbolises fidelity and eternal union. It is the tree to offer for a wedding or a birth. A symbol of strength, majesty, wisdom and nobility, it is also an ideal gift to express your respect and love for your father. Finally, it is the tree that links the earth to the heavens and opens the doors to the invisible world. It can be highly symbolic to plant a common oak when one has lost a loved one.