Welsh Journals

THE VEGETATION AND FLORA OF TYCANOL WOOD In its vegetation, and above all in its lichen flora, Tycanol Wood is a most remarkable wood certainly one of the most interesting in the whole of the southern half of Wales. Though managed by man from time to time, the woodland must certainly be regarded as primary woodland in the sense that almost certainly there has been some woodland cover on the site since Atlantic times. This is indicated by the extraordinarily rich cryptogamic flora, particularly of lichens and ferns, which contains many "old forest indicator" species that must once have been more or less continuously distributed in the former woodland cover of South Wales in suitable habitats, but whose distribution is now extremely fragmented; indeed there are at least seven lichen species present in Tycanol Wood that are not now known anywhere else south of Merioneth or north Cardiganshire. Ecologically, Tycanol Wood is remarkable for its range of habitats. This is due to its geological and topographic variation, in spite of the fact that no calcareous rocks are present. THE VEGETATION The northern and lowest part of Tycanol Wood lies on the soft ashy shales of the Fishguard Volcanics. which produce relatively rich brown forest soils where drainage is good, carrying mixed Oak-Ash-Hazel forest, with a relatively rich ground flora of numerous species of herbs typical of base rich deciduous woodland, such as Bugle (Ajuga reptans), Wood Speedwell (Veronica montana), Bluebell (Endymion non-scriptus) and Primrose (Primula vulgaris). Well grown specimens of Sessile Oak (Quercus petraea) and Ash (Fraxinus excelsior) occur here, though many of the largest trees were felled in the 1914-18 war. This part of the wood is diversified with open glades. Where the water table approaches the surface, flush and even swamp areas occur, dominated by Sallow (Salix atrocinerea) and Alder (Alnus glutinosa). Here the ground flora includes species of marsh or fen carr forming a tall herb community, containing such plants as Meadow Sweet (Filipendula ulmaria) and Valerian (Valeriana officinalis), and in more acid sites Star Sedge (Carex echinata) together with various species of Sphagnum. The southern and central parts of the wood lie on the dolerite, and here conditions are very different. Deep rocky gullies with cliff-like walls, rich in bryophytes, appear, together with the two Filmy Ferns (Hymenophyllum wilsonii and H. tunbridgense): the latter is extremely local in South Wales. Hay-scented Fern (Dryopteris aemula) also occurs in quantity on one shaded rocky bank. The tree canopy here consists largely of smaller, less well-grown Sessile Oak standards and some coppiced trees, with a ground flora largely dominated by Bilberry (Vaccinium myrtillus), with various ferns and bryophytes, including some interesting and local "Oceanic" species such as the hepatics Scapania gracilis, Saccogyna viticulosa, Bazzania trilobata, Plagiochila spinulosa and P. punctata, none of which is common in South Wales today. Wood Rush (Luzula sylvatica) is locally dominant also. As one moves towards the southern end of the wood, the ground rises on to dolerite crags which culminate in a feature very like a Dartmoor tor in