Coed-y-Brenin is a large forest of 9000 acres near Dolgellau, which was purchased by the Forestry Commission in 1922 and extensively re-planted. Historically it was part of the Nannau Estate founded by Cadwgan, Prince of Powys in 1100AD.
In the Ordovician Period, Rhobell Fawr, in the Arennig Mountain range in Snowdonia, was an active volcano surrounded by a shallow sea. As it erupted, rocks from deep underground were heated and pressurized as water percolated through the ground. The heat of the water dissolved metals from the rocks, and these were redeposited as metal ores such as copper and gold.
In the Roots of the Volcano is a geological forest trail known as Coed y Brenin. The forest has a unique location set in the valleys of the rivers Mawddach, Eden, Gain and Wen. Coed-y-Brenin connects Cadair Idris and Dolgellau to the South via the wetlands of Crawcwellt to Trawsfynydd and Snowdonia in the North. Inland are the Arenig Mountains and Bala and to the west lie Barmouth and the Tremadog Bay. The forest has a history of gold and copper mining and religious sites and it now has a reputation as one the foremost cross-country biking centres in the world. There are also walks and nature trails and wonderful wildlife habitats.
The forest has a mixture of diverse habitats, species and archaeology as a result of the geology, topography and climate.