Monday, 2 September 2013

Trip Report Savernake Forest

Bath Nats with Wiltshire Botanical Society in Savernake Forest, Saturday 31st August 2013

Around 30 members of Bath Nats and Wiltshire Botanical Society met on a sparkling late summer morning with Joan Davies and me for what was to prove a fascinating and varied day steeped in the extraordinary ancient and modern forest that covers 1100 hectares of the landscape just east of Marlborough, Wilts. After an introduction to the history of the forest from Joan and a call from me to imagine its inhabitant trees and fungi as living and dying fountains, we set off down one of the paths that had been specially cleared for our visit with the help of Tom Blythe of the Forestry Commission. It wasn’t long before our attention was diverted by one of the profuse outgrowths of sulphur polypore, Laetiporus sulphureus, which we were to see frequently on decaying logs and tree trunks during the day. I demonstrated the brown rot decay that this fungus produces in the heartwood of large oak trees. Soon we came across some more specimens on a log that also supported luxuriant growths of the mosses Dicranum scoparium, with its scythe-shaped leaves, and Tetraphis pellucida, which forms ‘gemma cups’, like tiny bowls of fruit at the tips of its shoots. Nestling amongst these was a tiny fruit body of the fungus, Galerina hypnorum, and on the path nearby a much larger fruit body of Tricholomopsis (=Megacollybia) platyphylla. I excavated the surface soil and leaf litter around this to reveal the spreading network of mycelial cords by means of which this fungus interconnects pieces of decaying wood over distances of many – perhaps even ultimately hundreds of metres in forests and woodlands. These cords form the communication channels from which the fruit bodies emerge as fountain-like outgrowths. At this point Joan reminded us that we had already been ‘walking’ for an hour, and had got less than a quarter of the way round our planned itinerary before lunch! So our pace had to quicken – which was difficult when there was so much to see and enjoy.
Eventually we reached the replacement King Oak. Joan explained that by the early 1900 the King Oak had completely died and in 1945 it was decided to replace it with a tree grown from an acorn from the original Savernake Cluster Oak. Unfortunately the leaves of the replacement oak show very little sign of clustering and the tree has grown poorly.  Both the replacement King Oak and the oak next to it have recently been pollarded in the hope of encouraging them to become the ancient trees of the future.

The replacement King Oak was the start of a parade of ancient oak trees that in all their decrepit, broken-hearted, heavy limbed, epiphyte-strewn, ridged, grooved and gnarled magnificence were our primary focus for the morning. Most impressive, for me, was one called the ‘Spider Oak’. We noticed how the distribution of epiphytic ferns, mosses and lichens on these trees followed the drainage patterns of rainwater down their trunks and branches, and reflected on the relationship between processes of growth, dysfunction, death and decay that contributed to their evocative appearance. We were concerned also by the luxuriant growth of bracken, bramble, young trees and other understory that blocked our access to them. This exemplifies one of the great difficulties facing managers of our forests in these times when the expectations of the public for access and recreation have been increased but their ability or willingness to contribute to what needs to be done has decreased. The increased growth of understory is due to the thinning out and removal  of trees around the ancient ones, which has allowed more sunlight to penetrate to ground level. To remove this growth without voluntary effort from the public is very expensive.

Eventually, we made our way out onto the ‘Charcoal Burners Road’ where we met Dr Jack Oliver, who informed us helpfully and in some detail how to recognise the two native species of oak and their hybrids and varieties that can be found in the forest – as well as the non-native ‘Turkey Oak’. We returned through the forest back to our starting point for a latish lunch, which some of us ate sitting around Thornhill Pond, where water soldier and fringed water lilies were seen, amongst other pond life. We then drove on to our afternoon destination and were led hastily along a cleared forest path to the base of one of the oldest oak trees in the forest, perhaps dating back to Saxon times and with a circumference at 1.5 m of 10.8 metres – the ‘Big Bellied Oak’. Amongst other things we admired on this old pollard was an outcrop of ‘beefsteak fungus’, Fistulina hepatica, on its flanks. We wandered more slowly back through the forest to our cars, admiring more magnificent oak trees and a specimen of the blusher, Amanita rubescens, along the way. But this wasn’t quite the end of the day for a group of about 15 of us, who walked on to Cadley Church, now a private home, where we were met by Rosemary Davies. Rosemary showed us around the graveyard and her garden, where over 120 species of colourful wax caps and other fungi have been recorded over the last 25 years or so since I last met her (but that is another story). We saw several red, yellow and blackening wax caps and some ‘white spindles’ (Clavaria vermicularis) as well as a little yellow brittle-gill, which my faltering memory eventually decided was Russula solaris, quite a rare species. Hence an already very enjoyable day ended on a high note.  Click Photos to enlarge
Exposing network
Spider Oak

getting logged

Alan Rayner
Photographs by Tom Cairns:

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