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| Site of Special Scientific Interest | |
|   Trees on the banks of the Afon Alwen | |
| Location | Clwyd | 
|---|---|
| Grid reference | SJ0014147618 | 
| Coordinates | 53°00′59″N3°29′24″W / 53.016515°N 3.4900015°W | 
| Interest | Biological | 
| Area | 42.82 ha | 
| Notification | 5 February 2003 | 
Coedydd Dyffryn Alwen is a Site of Special Scientific Interest in the preserved county of Clwyd, north Wales.
It contains a mix of different woodland types, reflecting the underlying geology and soil type, including ash, oak and rowan, with a hazel understorey, with a rich ground flora including globe flower, oak and beech fern. [1]