Parkhurst Forest, Isle of Wight, Saturday, 20th April 2013

Parkhurst Forest is the largest pasture woodland relic in the Isle of Wight with a rich ancient woodland lichen assemblage, but it had not been looked at for sometime. The meeting point was at the parking at Marks Corner at OS grid ref SZ470920 at 10.45am. The mainland contingent came over in two cars from Lymington and included Ginny Copsey, Andy Cross and Gary Palmer, Phil Budd and Paul with Neil Sanderson leading. As seems usual, my worries about getting over in time meant we caught an early ferry and got over far too early. So we started the survey early by making a small circuit around the 19th century Oak plantation by the car parking area. The weather was warm and sunny in the first good period of weather we had had for sometime; spring was finally here!

The surviving 19th century Oak plantations dating from after enclosure in 1815 are the main habitat of lichen interest within the forest; there are few pre-inclosure trees left. Dr Francis Rose found a moderate assemblage of more mobile ancient woodland lichen species with a NIEC ancient woodland lichen indicator score of 11 given an 1989 unpublished report. During casual visits I added a couple of rare species: Agonimia allobata Nb (NS) & NIEC indicator by the stream to the north west (SZ4691) in the early 1990s and and the very rare Byssoloma leucoblepharum NT (NR) to the north east (SZ477 918) in 1997 on a pre-enclosure Oak.

The 19th century Oak stand at Marks Corner we looked at first was a mixed Oak and Beech stand with a dense under storey of Holly (PA001, SZ471 919). The shade of the latter resulted in very species poor lichen assemblages on the trunks. Slightly better lit trees by the ride edges, however, produced a slightly greater diversity with a couple mobile old woodland species: Arthonia vinosa and Phaeographis dendritica recorded. The best find was Strigula taylorii Nb (NS/IR), an under recorded species of wound tracks on trees, on a wounded young Beech (PA001, SZ46505 91866); the third record for the Island. The species is easily over looked as Porina aenea, which was found with the Strigula on this tree, but well developed Strigula taylorii has a mixture of projecting pointed perithecia and globose pycnidia set more densely than the globose perithecia of Porina aenea.

The Beech tree with Strigula taylorii

After this we circled back to the car park and met up with the Island contingent of Les and Sheila Street and Colin Pope, along with Eric Clement from Gosport. Colin came with a report by Francis Rose and a map of the old trees compiled by a Forestry Commission employee. We first headed to a nearby area of open poorly growth Chestnut coppice (PA002, SZ470 919). This had no old trees but had a commodity that we were to find was in short supply deeper in; well lit and sheltered trunks. As well a good flora of common epiphytes there was a strong growth of Treebeards Usnea species, with Usnea cornuta abundant but a single thallus of Usnea ceratina, with the diagnostic C + yellow reaction of the medulla, but the spinules breaking down into soredia more than is usual, and a little Usnea flammea. Also present on the Chestnut was Cliostomum flavidulum Nb (NS), an under recorded species of old woodland, which was new to the forest and the second record for the Island. This species is described further at waypoint PA008.

We then headed south east off the Mark's Corner plateau and down into a valley, aiming to pick up trees recorded by Francis Rose in the 1980s (PA003 – PA007, SZ472 919 to SZ474 916). There is plenty of early 19th century Oak here. This started off well (PA003, SZ47240 91910), with a better lit Oak with the old woodland species Phaeographis dendritica and Schismatomma niveum Nb (IR) and more Cliostomum flavidulum Nb (NS). After this, however, the full canopy and dense regeneration of Holly and Beech meant that there was very little lichen growth at all on the trees. Further down we searched an area where Francis Rose recorded the old woodland species Anisomeridium ranunculosporum, Punctelia reddenda, Schismatomma niveum Nb (IR) and Schismatomma quercicola Nb (IR). After much struggling thew dense Holly a tiny scrap of Schismatomma quercicola Nb (IR) was found at PA004 (SZ47421 91860) and a big colony of Schismatomma niveum Nb (IR) at PA005 (SZ47399 91742). This area had clearly been degraded as a lichen habitat by increased shade since the 1980s.

The densely shaded formerly lichen rich area

To the south, a ride side Oak (PA006, SZ47400 91647) supported more Cliostomum flavidulum Nb (NS), which was proving to be widespread, and a second Strigula taylorii Nb (NS/IR) colony was found on a nearby Beech. Another better lit ride side Oak had base rich bark with Normandina pulchella. At the ride junction (PA007, SZ47407 91631) another well lit Oak supported Arthonia vinosa, with well developed dark apothecia, rather than the red flecks formed by pycnidia normally seen in the south, along with Schismatomma niveum Nb (IR). To the south the local Scoliciosporum pruinosum was recorded on an Oak.

This section of the forest is now deeply shaded but some interest still survives on ride side trees, with a NIEC ancient woodland indicator index score of four and four Notable species recorded.

We now walked west heading for an area of the forest with frequent old trees but probably never full explored for lichens. The wide ride here had a fine display of woodland spring flowers, including the Lungwart Pulmonaria longifolia and Phil and Paul were spotting insects including Bee Flies, with a Coma and a Brimstone flying by.

Pulmonaria longifolia

Working over to the west of the forest we passed a very big pre-enclosure Oak at PA008 (SZ47120 91557) by a forest road. This was not especially rich but was of interest for the close proximity of the common Pyrrhospora quernea and the over looked Cliostomum flavidulum Nb (NS). Both are yellow sorediate crusts and the latter has been over looked due to the abundance of the former. The spot test are very different, with Pyrrhospora C + orange and Pd – and the Cliostomum C – and Pd + yellow then very rapidly red but, once learned, the rarer species is easy to pick out by eye. It has much brighter yellow colour with fine soredia compared to the dull mustard yellow and coarse soredia of Pyrrhospora quernea. Also present were the nutrient demanding lichens Amandinea punctata and Lecanora hagenii, probably reflecting dust deposition from the adjacent forest road.

Pyrrhospora quernea and Cliostomum flavidulum

Into the western section of the forest, the first interest was a ride side old Oak (PA009, SZ46660 91728) with base rich bark with two characteristic old woodland species of this habitat; Catinaria atropurpurea, with dark disks, and Pachyphiale carneola, with clear red disks. Both are among the most mobile old woodland species of base rich bark, but both were new records for Parkhurst Forest, and good additions to the Forest list. An adjacent Oak (PA010, SZ46660 91728) supported the old woodland species the old woodland species Phaeographis dendritica and Schismatomma niveum Nb (IR).

We then headed south west to an area where I had recorded Agonimia allobata Nb (NS) in the 1990s, Francis Rose had recorded some important Oaks with base rich bark and the old tree map showed many old Oaks. This area was found to now be desperately over grown, with even the rides lost to dense Bramble with a thick under storey of Sycamore between the trees. It proved to be very hard work to get around in and, after a short attempt, we gave it up as no fun at all. In the short section we looked at we did record the old woodland species Arthonia vinosa and Schismatomma niveum Nb (IR) on an old Oak at PA011 (SZ46515 91395), an Oak at PA012 (SZ46429 91461) with Schismatomma niveum Nb (IR) and a Holly at PA0132 (SZ46523 91406) with Stenocybe septata Nb (IR).

Western Woodland

We then headed north to the lane on the northern edge, passing more Oaks with Schismatomma niveum Nb (IR) (one Oak at PA014, SZ46578 91775 and several at PA015, SZ46505 91866). The western area actually proved richer than the Marks Corner area, with a NIEC ancient woodland indicator index score of six and two Notable species.

In total we recorded 42 taxa (see species list), with a NIEC ancient woodland indicator index score of eight along with five Notable species. We added 2 NIEC indicator species, and this brings the total NIEC indicator score for the forest to 14; not a high one for an old growth woodland but a good one for what is largely 19th century Oak plantation. We found the forest's lichen old woodland assemblage to be suffering from increasing and dense shade. The absence of deer on the Island is good for many aspects of woodland ecology and conservation, but is not good for relic pasture woodland sites. Deer browsing can maintain some openness in relic pasture woodlands. The fate of the Parkhurst Forest lichens, shows that if then out of control deer populations on the mainland are got on top of, then there will be a need to restore controlled grazing to relic pasture woodland sites. This is not a point that the BLS has yet been able to get over to the conservation authorities (Brain Edwards, pers. com.). At Parkhurst, there are plans to restore grazing see Parkhurst Forest: Forest Design Plan - Forestry Commission, although it is notable that the western area, where we found the more old woodland lichens than around Mark's Corner, is not an area proposed for pasture woodland restoration. There is clearly a need for an up to date full lichen survey to locate where the relic lichen interest actually is. The plan appears to be based on Francis Rose's survey, but this was never a full survey nor intended to map the interest of the forest comprehensively.

Species list

Download KMZ file to view route and waymarks in Google Earth, or view as picture below

We finished quite early, having been repulsed by Brambles, so stopped of at the Street's house for a look at their local Goldeneyes Teloschistes chrysophthalmus (see link & link) and have tea. The Teloschistes was a small thallus on the south side of a Hawthorn bush at Newtown Meadows with species in close association (c10cm) being Evernia prunastri, Lecanora chlarotera, Physcia tenella and Xanthoria parietina, the latter rare, and nearby species Lecidella elaeochroma f. elaeochroma, Melanelixia subaurifera, Ramalina farinacea and Ramalina fastigiata. The community is similar to that found at Keyhaven, with some highly nutrient demanding species such as Xanthoria parietina present but with moderately nutrient demanding grey lichens such as Ramalina species prominent and the ammonium hating Evernia prunastri present. This is a very typical community for Goldeneyes and and is discussed further here.

Afterwards we had tea and biscuits, then rushed off to just miss the early ferry.