sweet acorn oak

Quercus rotundifolia is a medium to large tree, usually 8–12 m (26–39 ft) in height, but can reach up to 15 m (49 ft) with a large, dense, rounded canopy. It has small, leathery, dark-green leaves with a glaucous, densely pubescent underside usually suborbicular to elliptical or lanceolate and are generally spiny to dentate on a younger tree. It has a semi-hemispheric cupule. It flowers from February to April. Seedlings will start flowering at about eight years old, but they will not start producing acorns until 15 to 20 years old, although trees in humid, good quality soils can start production as early as 10 years. The acorns ripen in autumn, about six months after pollination. It is a resilient tree that can survive temperatures below −20 °C (−4 °F), and that on occasion reach 47 °C (117 °F). As opposed to Quercus ilex, its acorns have a very low level of bitterness tannins and so are generally sweet and a good energy source for livestock.

Quercus rotundifolia is native to most of the Iberian Peninsula (Portugal and Spain), but is also distributed throughout Morocco, especially in the Atlas Mountains, Algeria, Tunisia, southern France (Languedoc-Roussillon) and the Balearic Islands. It is present in continental, sub-continental or littoral Mediterranean areas but always in climatic conditions determined by a fairly hot and dry summer, which excludes the wet, oceanic influenced climate of Green Spain and northwest Portugal, but requires wet winters as the tree is absent from arid climates and those with no real wet months like southeast Spain. It grows in a variety of soils and is indifferent to variations in edaphic conditions, persisting in soils with pH from six to eight. The tree is also associated in Iberian holm oak/Atlas cedar forests of the Atlas Mountains. In Morocco, some of these mixed forests are habitat to the endangered Barbary macaque. The tree inhabits dense oak forests, open oak forests and dehesa ecosystems, from sea level up to 1,900 m (6,200 ft) a.s.l. It can live in all altitudes in Portugal, switching with Quercus suber. …