Wistman's Wood at 410 metres is one of three remote high-altitude Oak-woods on Dartmoor. Designated an SSSI in 1964, it now forms part of a larger National Nature Reserve, covering about 3.5 ha. The wood occupies a sheltered, south-west facing slope, on a bank of granite boulders, interspersed with pockets of acid, free-draining, brown earth soil.
It is a remnant of an ancient forest that covered much of Dartmoor before Mesolithic hunter/gatherers cleared it around 5000 BC. The oldest Oaks appear to be 400–500 years old, and originated within a degenerating Oakwood that survived as scrub during a global cooling period in the 16th and 17th centuries. The wood has changed considerably since the mid-19th century due to an increase in average temperatures. Not only have the older oak trees grown from a stunted/semi-prostrate to a more ascending form, but a new generation of mostly straight-grown and single-stemmed oaks have developed on the outside of the wood.
The trees are mainly pedunculate oak (Quercus petraea), with occasional rowan (Sorbus aucuparia), holly (Ilex aquifolium), hawthorn (Crataegus monogyna), hazel (Corylus avellana), and willow (Salix caprea). Tree branches are characteristically festooned with a variety of epiphytic mosses and lichens and, sometimes, by grazing-sensitive species such as bilberry (Vaccinium myrtillus) and polypody fern (Polypodium vulgare).