The Jura is home to one of the largest mid-mountain forests in France, with more than 617,763 acres (250,000 ha) covering 50% of the department. In the plain, the Chaux forest is the 2nd largest deciduous (oaks, beeches) forest in the country. At altitude extend the largest fir forests in Europe with spruces several hundred years old like in the forest of Joux. Their proximity to Switzerland, where the Eurasian lynx was reintroduced in the 1970s, has caused its return to the forests of the Jura.