Foresters are carrying out vital work on ancient oak trees which provide a life support mechanism for some of the rarest lichens in the United Kingdom.
It’s hoped the pruning of the oaks at Pont LLogel woodland near LLwydiarth, Powys, will prolong the life of the trees upon which the precious lichens depend.
The important lichens which grow on the trees in the Forestry Commission Wales managed woodland can only be found in small numbers in the far west of the British Isles and in northern Scotland.
But many of the oaks were becoming top-heavy and vulnerable to windblow, so FC Wales arboriculturalists Medwyn Davies and Dave Williams have stepped in to trim off some of the weighty branches.
It’s painstaking work, for the lichens are so sensitive to change that anything too drastic could have a catastrophic effect on the rare plants.
Jim Ralph, FC Wales local area manager in Pont Llogel, said, “These particular lichen species depend upon the trees’ survival, as the level of shading and changing conditions can be too rapid if the tree dies. When the trees fall over and die they become of no use to these important lichens in a very short time.
“This is why only a few shading trees or branches are removed at once. The lichens will then be monitored to gauge their response before we plan to remove a few more branches, maybe in five to 10 years.”
FC Wales acquired the woodland in the early 1940s and subsequently planted conifers in order to provide timber for the nation’s depleted resource.
Following the discovery of the lichens and rare flowering plants, the site was designated a Site of Special Scientific Interest (SSSI) by the Countryside Council for Wales in the early 1980s and FC Wales began to manage the woodland with the focus on conservation and biodiversity.
Among the notable ancient-woodland lichens on the site are:
- the large, leafy lichen Peltigera horizontalis, which grows on three trees;
- Biatora sphaeroides (which has recently changed its name to Mycobilimbia pilularis) can be seen on about eight trees;
- Phyllopsora rosei, for which the UK has international responsibility because of its restricted range on the continent, grows on four trees at Pont Llogel;
- Thelotrema lepadinum, which looks like little barnacles, is more widespread and is known from around 20 trees, though it is likely to be seen on many more;
- Lobaria pulmonaria is found on one tree and is now very scrappy in appearance. This species is very vulnerable to increases in atmospheric nitrogen, and is in decline.
Jim said, “As there are now so few trees in Montgomeryshire supporting ancient woodland lichens like this, we find ourselves in the situation where any work we can do to protect individual trees is worthwhile.
“Lichens are renowned by monitors of climate change as being one of the key indicators for air pollution, so it’s important that we look after these sites in order to understand changes that are happening to our planet.
“This important pruning work forms part of a wider programme of conservation that FC Wales carries out each year to improve the biodiversity of the woodlands under our management.”
The susceptibility of the plant species, especially the lichens, to rapid change means the management of Pont Llogel SSSI is a slow and progressive process.
It’s believed Pont Llogel is favoured by the rare lichens because the area escaped the worst effects of the industrial revolution and accompanying air pollution which impacted on woodlands closer to industry during the early 20th century.
The humidity from the nearby river Vyrnwy, complemented by the rainfall drawn into the valley from the Berwyn mountains, also help to provide perfect conditions for these species.
Alastair Hotchkiss, CCW Conservation Officer for Montgomeryshire, welcomed the work and said, “In many ways, the remaining lichens and the flowering plants of Pont Llogel are like a little bit of the north-west Highlands of Scotland tucked away in a mid-Wales valley.”
