Coedydd Glannau a Cwm Coel

Also within

Powys County

Habitats

Fast flowing river and stream

Geology & landscape

Geological Period: Silurian

Landscape processes: Glacial

Description

Description Glannau is a particularly diverse example of a sessile oakwood Quercus petraea developed on Silurian strata. The central area is fairly open with mainly oak trees present; a south-east section comprises mixed deciduous woodland with frequent occurrence of dog's mercury Mercurialis perennis in the ground layer and another area of dense wood occurs to the north-west in which sycamore Acer pseudoplatanus and beech Fagus sylvatica occur with the oaks. The wood has a locally well developed bryophyte flora, especially on rock outcrops where the shales are fairly calcareous. A fourth section to the wood, adjacent to the shores of Garreg Ddu Reservoir, has a well developed ground layer and epilithic flora only sparsely represented in the rest of this wood. The Cwm Coel woodland complements the interest of Glannau in that it is a sessile oakwood with well grown oaks in which locally a herb-rich flora has developed, particularly in association with a stream that runs through it. South of the stream the woodland contains a number of species not represented elsewhere in the Cwm Coel woodland including wood horsetail Equisetum sylvaticum and beech fern Phegopteris connectilis. Wilson's filmy-fern Hymenophyllum wilsonii, a species more characteristic of oceanic areas and a very rare plant in Radnor, occurs by the stream. Local areas of base-richness in the woodland permit species such as enchanter's-nightshade Circaea lutetiana and guelder-rose Viburnum opulus to occur. An unusual species more typical of the generally acidophilous nature of the site is royal fern Osmunda regalis. Old oak trees and decaying logs support an exceptionally rich epiphyte flora of lichens, mosses and liverworts. Species include the subterranean liverwort Cryptothallus mirabilis at one of only two known sites in mid-Wales.

Species mentioned

Plant communities