A fast-growing tree, capable of reaching heights in excess of 100ft, the ash ( Fraxinus excelsior) is a relative of the olive and grows throughout Europe. Currently the fourth commonest tree in the British flora, the ash is adaptable to growing either as a standard tree, providing high quality, flexible timber, or in coppices, where it provides an unrivalled range of uses. Its firewood is also the most valuable available, and in Ruskin 's time, the ash was still a crucial part of the rural economy.
In norse mythology, the sacred tree Yggdrasil, the Tree of the World (and the Tree of Healing and Rebirth) was an ash, and this tree also makes up one of the thirteen tree moons of the Celtic alphabet calendar, and a common element of most European pagan iconography in pre-Roman times.
Although it appears not to be a particularly significant tree to Ruskin, the ash appear often in Ruskin's discussions of specific landscapes, including Turner's Bolton Abbey scenery ( Works, 5.163-5; 6. 304-6), the ash-and-oak country around Sir Walter Scott's house at Ashestiel ( Works, 29.462), and in Ruskin's discussion of the Mediaeval landscape idea in Modern Painters III ( Works, 5.283). In Proserpina, Ruskin evokes the limestone ash habitats around Malham Cove as a type of perfect wild growth ( Works, 25.293), but does not closely scrutinize ash botany either in that work or in any detail in the earlier botanical sections of Modern Painters V ( Works, 7.38-9).