autumn colors in the mixed mountain forests of the ordesa-viñamala biosphere reserve, pyrenees

abies acer alba alpine and aragón area autumn beech betula biodiversity biome biosphere birch boreal climate colors dams deciduous degradation directive ecoregion ecosystem ecosystems effectiveness european fagus fir forests habitat habitats high huesca hunting leaf logging management maple montane monte mountain national oaks ordesa park perdido pine pristine protected pyrenean pyrenees range reserve resorts silver spain sylvatica tena tree trees valley viñamala winter yew