At Tieiras there exists woodland that is dominated by the Pyrenean oak, one of the native species of the Peneda-Gerês National Park. The Pyrenean oak is mainly present in the higher altitude areas, as is the case with where we are now, which lies at an altitude of between 850 and 1000 meters. This type of woodland is one of the natural habitats of this region, featuring Galaico-Portuguese oaks such as Quercus robur and Quercus pyrenaica. It is also one of the habitats of European Community interest, and is listed in the Habitats Directive, and as such the Portuguese State is entrusted with its protection and fostering its conservation status. Oak woods make an important environmental contribution including climate regulation, soil formation and retention, biodiversity, food production, recreation, among others. They are vital to other biological communities, being fundamental in the breeding cycle of many species.
In Addition to the oak, we can find here other species of indigenous flora, such as holly, blueberry, dog tooth and the wood anemone. Tieiras wood also has a very significant presence of lichen covering the trunks of oaks, a feature that indicates the absence of atmospheric pollution. There is also an extensive moss coverage thanks to humidity in the woodland. Among the animals found here are deer and small mammals such as marten together with countless forest environment birds such as goshawk, great woodpecker, coal tit and jay.