It is a tree of wide distribution in the Mediterranean Spain with an average size of up to 20 meters high. The gall-oak is a tree of cup generally collected and sparse and variable size depending on the vicissitudes that has suffered from shrub to slender and straight. The leaves are simple, alternate, with leathery blades and a great variability in shape and size, they are also marcescent and even remain green practically until the new ones appear. They have a glossy green color by the beam and lighter by the underside, with its edge with shallow teeth, sometimes sharp. Typical of gall oaks and other oaks are the galls, which are balls the size of walnuts, brown in colour, which have prominences with a spongy, corky interior. The fruit is an acorn that has a dome covered with aovate scales, and velvety appearance; the acorns are arranged in clusters and grow on short stalks. It blooms between April and May; acorns ripen and spread around September or October. The gall-oaks can live several centuries, having found specimens over a thousand years. Its wood can be used when it has suitable dimensions and shapes in construction, to make beams, but it has mainly been used as firewood for local use and to make charcoal. But the species has a high protective, refuge and trophic resource value for wildlife. Their presence on the cooler slopes and better soils of the Somontanos and the foothills guarantees good acorn harvests most years. It is a noble species that creates soil and protects against erosion due to its powerful roots, which makes it very valuable in the mountains and slopes with a clear protective vocation. The gall oak grows on all types of soils, even on lime-rich soils, withstands very well in very contrasting (continental) climates, and can climb up to 1900 m in the southern mountains. It requires conditions similar to that of the oak, although it needs some more moisture and fresher and deeper soils, and resists prolonged summer drought less. It is often associated or in contact with other species of the genus such as holm oaks, myrtle and cork oaks.