Ancient Tree Forum

Lobarion on ancient wych elm in Cumbria		The various plants which exploit the bare wood surfaces of trees as a place to grow includes mosses, liverworts, lichens and algae. The gradual build-up of these species into recognisable communities, as species colonise, grow and reproduce, is a very extended process, taking decades and even centuries to reach the full expression of diversity that can be achieved in this country. So the richest sites tend to be those with the oldest trees - depending on local conditions of course, notably air pollution levels as most are intolerant. A combination of adequate light levels, humidity, shelter and so also contribute. the need for good lighting means that it is the large old open-grown trees which support the richest epiphyte communities, rather than trees in closed canopy woodland. Succession Two year old twigs support different associations of species to say older branches and the ultimate species-richness of old trunks. Smooth-barked trees support different communities to heavily ridged trees, involving variability due to genetics, position, life history, etc, as well as due to different species. Lobarion The Lobarion is the famous community of ancient wood pastures, and occurs on the trunks and major boughs. It comprises the dramatic foliose species such as the tree lungwort Lobaria pulmonaria and rarer closely-related species such as Lobaria virens. the reddish liverwort Frullania tamarisci is a good indicator of the community as it is often very visible from a distance.The Lobarion is confined to large old oak, ash and beech over much of lowland Britain, but the further west one travels then increasingly it may be found on younger trees. It is also more widespread in the west, due to the higher levels of air pollution in the east. Even with reduced air pollution it will take a very long time for this community to return to eastern woods. Lecanactidetum premneae This is the other classic ancient tree epiphyte community and is normally only found on trees at least 250-300 years old, and is mainly known from old pollard oaks, whose bark has become dry and brittle with age. The community is named for the major species in southern Britain...the crustose Lecanactis premnea. It is truly the ancient tree lichen community!

		Further reading: Francis Rose Ancient British woodlands and their epiphytes (British Wildlife 1993 5: 83-93)

Epiphytes