Grass Wood is a nature reserve in Wharfedale, managed by the Yorkshire Wildlife Trust and a Site of Special Scientific Interest (SSSI). It is situated on the west and south facing slopes of a bench of Carboniferous limestone, and so the woodland grows out of limestone scars, limestone pavement and scree. Beech, sycamore, spruce, larch and pine were planted into the woodland in the twentieth century and these are gradually being removed to restore the wood to its natural canopy composition of ash, wych elm, oak and hazel.
The ground flora in Grass Wood is particularly species-rich. The best time to see it in flower is late March to early June. Species you may see include lily-of-the-valley, stone bramble, mountain melick, common valerian, wild angelica, salad and great burnet, melancholy thistle, lady's-mantle, angular Soloman's seal, common rock-rose, bloody crane's-bill and betony. The nationally scarce rock whitebeam also grows here. Like Lower Grass Wood, Grass Wood is a good place to see and hear woodland birds such as tree pippit, wood warbler, pied flycatcher and redstart and to see butterflies on dry, calm days. Small groups of roe deer can also be seen in the quieter parts of the wood. Grass Wood is a short walk from the characterful village of Grassington along the River Wharfe or via the Dales Way.