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Lobarion on ancient wych elm in Cumbria
Lobaria verins
taken from leaftlet from Plantlife |
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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.
Ancient trees and their lichens need active management.
● Keep ivy under control. Too much can shade out the lichen interest.
● Keep slurry, dung and artificial fertilizers away from the trees as these
materials all kill lichens.
● Site intensive livestock units and slurry and dung stores well away
from ancient trees.
● Consider tree surgery to prolong the life of the trees.
Atmospheric Pollution combined with the loss of ancient trees has all but
led to the extinctions of these beautiful organisms across most of lowland
Britain.
A
leaflet
pdf (3.23 MB) from
Plantlife has been funded by the Wales Biodiversity Partnership to
encourage the
conservation of the Lobarion, a community of lichens of principal importance
in Wales. pdf (3312KB)
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! |
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Further reading:
Francis Rose Ancient British woodlands and their epiphytes (British Wildlife
1993 5: 83-93) |
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