Trees The holm oak (Quercus rotundifolia) is the most abundant native tree species in the region, and the main species responsible for the few observable shadows. Beneath them, many animals protect themselves from the scorching summer sun. The branches and bark are habitats for a wide variety of insects and other invertebrates, attracting insectivorous birds such as the green-woodpecker. Holm oaks have a variable size but, in the case of woodlands (montado), because of pruning and woodcutting, trees are mostly 12-15 m tall. Due to the persistent nature of the leaves (2-4 years), the canopy appearance changes little throughout the year, except for a yellowish colour in the spring attributable to the male flowers (aments). The fruits, acorns, ripen from late autumn and are an important part of the diet of mammals such as wild boar and small rodents such as the wood mouse. Acorns are one of the main resources for pigs raised in montanheira. Over the centuries, holm oak wood has been used for construction, because it is dense, resistant to rot and also to attack by xylophagous insects (wood consuming).