Oaks are keystone species in European temperate forests. Nemoral oaks (Quercus robur, Q. petraea) are widespread all throughout the continent, but reach their southern distribution boundary in northern Iberia. In the Mediterranean Region, they are replaced by evergreen oaks, but ‘sub-Mediterranean oaks’, i.e., drought-resistant deciduous oaks with marcescent leaf habit usually occur at the transition areas. But according to prediction models, climate change is expected to modify the future distribution areas of these species.