Izki is mainly made up of Pyrenean oak, but there are also different types of trees, such as beech, holm oak, alder, gall oak, mixed forests, birch, aspen groves, oak groves… they cover a large part of this natural space.
On the slope of the Soila, there are two types of yew tree (Taxus baccata) and lime tree (Tilia platyphylos) which, for different reasons, are protected as “Singular Trees”
Small rivers -Izki, Molino, Berrón- flow through the valley. At some points, the water rises to the surface forming ponds, marshes and incipient peat bogs. In these wetlands, as well as an interesting fauna of amphibians and birds – little grebes, great crested grebes… -, valuable flora is also found, such as the white water lily and a rich variety of carnivorous plants.