According to Silva & Gavinhos (2002), since the last glaciations, the landscape has undergone changes related to the climatic variations that have occurred during the Quaternary era.  In the glaciation period, the mountain zone was likely dominated by the Scot pine (Pinus sylvestris L.), and where the valleys are more protected there was probably a zone of forests of mixed oak.

 

With the occurrence of global warmng, this type of vegeation gradually colonized the adjacent areas, until it became like the pre-current situation.

 

During the last 5,000 years, the vegetation has undergone a significant modificaion due to the actions of man.  The original mixed oak forest has gradually given way to scrubland and the areas cultivated in the last 60 years were substituted by Maritime Pine (Pinus pinaster Aiton) and Eucalyptus (Eucalyptus globulus Labill.).

 

The natural and semi-natural vegetation varies altitudinally according to the exposure of the slopes.

 

North and West slopes – The Castnea sativa forests and the mixed forests of Quercus robur and Q. Pyrenaica with other species namely Sorbus latifolia e S. torminalis, Ilex aquifolium dominate.  In the permanent lines Alnus glutinosa and Fraxinus angustifolia sharply Ulmus glabra and Corylus avellana and in the temporary water lines Salix atrocinerea dominates.

 

The scrubland is characterized by yellow portuguese broom and heather with coots.

 

South and East slopes  – They are dominated by mixed forests of Q. pyrenaica and Q. suber.  In the permanent water lines Alnus glutinosa e Fraxinus angustifolia dominate and in the temporary water lines it is Salix atrocinerea.  The scrubland is characterized by white flower portuguese bloom (C. multiflorus) and gum rockroses (Cistus ladanifer)

 

Summit  zone – The highest zone does not have tree formations and is dominated by Portuguese broom, heather and echinospartum ibercum with more humid depressions and semi-natural pastures.