Quercus rotundifolia, the holm oak or ballota oak, is an evergreen oak native to the western mediterranean region, the majority of trees are growing on the Iberian Peninsula with minor populations in Northwest Africa. This subspecies is an important part of an existing and ancient agroforestry system that is locally dominate in many areas of southern Portugal and Spain.

It is a tree that can reach 20–25 meters in height in exceptional cases, but it is more common to see trees that are 14-15 m tall and on average do not exceed 5-8 m, much depends on the soil they have to grow in. Quercus ilex rotundifolia is an excellent shade tree and an essential resource for birds and insects.

It is a highly adaptable species recommended for afforestation in the hottest and driest regions of the Portugal. It has the ability to persist as a forest in poor soils (stony and rocky soils) and harsh climates. In doing this, it provides organic matter in depleted soils, and the deeply developed and expansive root system protects the soil against erosion. The holm oak tree retains the ability to sprout from the roots throughout its life and, until it reaches 200–300 years of age, it has the ability to sprout from the stump. This trait allows recovery after strong disturbances such as fires and makes it suitable for creating firebreaks. Montados (dehesa in Spain), is an agrosylvopastoral system and cultural landscape found in southern and central Spain and southern Portugal, often dominated by Quercus ilex rotundifolia. The use of the ballota in the creation and maintenance of Montados is considered the best way (ecologically as well as economically) to use marginal land for agriculture.