These woods, based on the Gall oak group (Quercus faginea), represent the transition from beech woods to humid oak woods.
They are mainly present in the central part of Navarre, in medium-sized mountain areas and always mid slope. They seek sunny slopes protected from water with sub-Mediterranean climates and precipitation levels of between 500 and 1,000 mm. a year and heights of between 500 and 1,200 metres.
Traditionally, these woods have been exploited for firewood, making it difficult to find mature examples with hollows capable of providing refuge to birds.
Gall-oak woods are not very dense and are interspersed with other tree and bush species such as maple, sycamore, checker tree, service tree, hawthorn, sloe, juniper, heather and box. The underwood is generally fairly thick and varied, more southern, sunnier gall-oak woods being home to typically Mediterranean species such as rosemary, thyme, lavender, etc.Birds:
Gall-oak woods have varied bird communities with relatively high densities of around 100 birds/10 Ha. thanks to their heterogeneity in terms of landscape and vegetation.
he characteristic species are the Common Woodpigeon, European Turtle Dove, Common Cuckoo, Great Spotted Woodpecker, Iberian Green Woodpecker, Wryneck, Tree Pipit, Wren, Robin, Blackbird, Blackcap, Subalpine Warbler, Spotted Flycatcher, Redcrest, Short-toed Treecreeper, Blue Tit, Great Tit, Long-tailed Tit, Greenfinch, European Serin, Goldfinch and Common Chaffinch.
Somewhat scarcer are the Stock Dove, European Nightjar, Golden Oriole, Garden Warbler, Common Whitethroat, Iberian Chiffchaff and Eurasian Jay.
There are several birds of prey: Black Kite, Red Kite, Sparrowhawk, Booted Eagle, Short-toed Eagle, Common Buzzard and Hobby. The Tawny Owl, Little Owl and Scops Owl feature among the nocturnal species.