Coed Cwm Cletwr

Also within

Dyfed County

Geology & landscape

Geological Period: Ordovician, Silurian

Description

Description This long and narrow sessile oakwood, situated along the Afon Clettwr, upstream of the village of Tre'r-ddol, overlies Silurian rocks, but is in close proximity to the Ordovician outlier of Pumlumon. The tree canopy is chiefly of sessile oak Quercus petraea, but this gives place locally to ashwood with occasional wych elm Ulmus glabra, aspen Populus tremula and small leaved-lime Tilia cordata. It is in the ashwood that the flora is richest, and where the presence of calcicole species indicates patches of lime-rich soil in a predominantly acid terrain. Similar patches occur in the two valleys Llyfnant and Einion to the north suggesting that a band of calcareous rock extends south-west from Machynlleth across all three valleys. Flowering plants (140 spp. recorded to date) are in much greater variety than in most woodlands in the district, and besides sheets of dog's mercury Mercurialis perennis and much sanicle Sanicula europaea, there is also woodruff Galium odoratum, yellow archangel Lamiastrum galeobdolon, wood speedwell Veronica montana and guelder rose Viburnum opulus. Sixteen species of fern, including oak fern Gymnocarpium dryopteris, beech fern Phegopteris connectilis and Wilson's filmy-fern Hymenophyllum wilsonii, and 90 species of mosses and liverworts have been found to date. The lichen flora is also diverse and of great interest. Of special interest is toothwort Lathraea squamaria, only known in one other locality in Ceredigion. Remarks: Most of the site is a nature reserve of the West Wales Naturalists' Trust. Partly owned by the Forestry Commission.

Species mentioned