Upland woodland was once a much more common feature in the North Pennines landscape, but the remaining woodlands are important for their contribution to the landscape and for the biodiversity which they support.
There are approximately 5,000 hectares of woodland in the North Pennines . There are 930 hectares of ancient and semi-natural woodland, much of which occurs in steep gills, which have been difficult to graze with sheep or clear for agriculture. Others are found along river valleys, particularly the Allen and South Tyne. Conifer plantations make up a substantial proportion of the woodland cover of the AONB, but there are also mixed ash, oak and wet woodlands. Some of the conifer plantations support red squirrel populations such as at Killhope Museum. Some great woodlands to visit include Derwent Gorge and Muggleswick wood, Allen Banks and Staward Gorge and Hamsterley Forest.