Coed y Cerrig
Geology & landscape
Rock Type: Sandstone
Landscape processes: Glacial
Description
Description This woodland covers the floor and north and south aspects of a glaciated valley on Old Red Sandstone. Woodland types include alder Alnus glutinosa over rich ground flora on the ill drained valley floor. Ash Fraxinus excelsior and wych elm Ulmus glabra are dominant along the tributary streams with oak Quercus robur and Q. petraea dominant on the slopes. A glacial spillway is a geomorphological bonus to the area. Remarks: Lies within the Brecon Beacons National Park. Local Nature Reserve declared by the Brecon Beacons National Park in 1977 comprises 5.9 hectares in the centre of the SSSI.
Species mentioned
Show the 4 species mentioned in the description, with red-list status| English name search for this in other sites |
Latin name search with Google |
IUCN / Red List | Type | Family |
|---|---|---|---|---|
| alder | Alnus glutinosa | LC | tree | salicaceae |
| ash | Fraxinus excelsior | LC | tree | oleaceae |
| common oak | Quercus robur | LC | tree | fagaceae |
| wych elm | Ulmus glabra | LC | tree | ulmaceae |
Insects to look out for
These moths, butterflies and beetles are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.
| Species | Status | Via host-plant |
|---|---|---|
| Oak lutestring Cymatophorina diluta |
Endangered | Quercus robur |
| Scarce vapourer Orgyia recens |
Endangered | Alnus glutinosa, Quercus spp., Ulmus spp. |
| White-letter hairstreak Satyrium w-album |
Endangered | Ulmus glabra, Ulmus spp. |
| The sprawler Asteroscopus sphinx |
Vulnerable | Fraxinus excelsior, Quercus spp., Ulmus spp. |
| Broom moth Ceramica pisi |
Vulnerable | Ulmus spp. |
| Mottled umber Erannis defoliaria |
Vulnerable | Quercus spp., Ulmus spp. |
| The lackey Malacosoma neustria |
Vulnerable | Quercus spp., Ulmus spp. |
| Pale brindled Phigalia pilosaria |
Vulnerable | Alnus glutinosa, Fraxinus excelsior, Quercus spp., Ulmus glabra |
| Early moth Theria primaria |
Vulnerable | Quercus spp. |
| Pale eggar Trichiura crataegi |
Vulnerable | Quercus spp. |
| Oak hook-tip Watsonalla binaria |
Vulnerable | Quercus robur |
| Flounced chestnut Agrochola helvola |
Near Threatened | Quercus spp., Ulmus spp. |
| Light crimson underwing Catocala promissa |
Near Threatened | Quercus robur |
| Dark crimson underwing Catocala sponsa |
Near Threatened | Quercus robur |
| Dusky-lemon sallow Cirrhia gilvago |
Near Threatened | Ulmus glabra |
| The sallow Cirrhia icteritia |
Near Threatened | Ulmus glabra |
| Dingy mocha Cyclophora pendularia |
Near Threatened | Alnus glutinosa |
| Heart moth Dicycla oo |
Near Threatened | Quercus robur |
| Kentish glory Endromis versicolora |
Near Threatened | Alnus glutinosa |
| Large thorn Ennomos autumnaria |
Near Threatened | Alnus glutinosa, Quercus spp., Ulmus spp. |
| September thorn Ennomos erosaria |
Near Threatened | Quercus spp. |
| Dusky thorn Ennomos fuscantaria |
Near Threatened | Fraxinus excelsior |
| Double dart Graphiphora augur |
Near Threatened | Quercus spp., Ulmus spp. |
| Clay fan-foot Paracolax tristalis |
Near Threatened | Quercus spp. |
| Common fan-foot Pechipogo strigilata |
Near Threatened | Quercus robur |
| Frosted green Polyploca ridens |
Near Threatened | Quercus robur |
Host-plant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.