Coed y Rhygen National Nature Reserve

The reserve lies on the steep, boulder-strewn north- and north-eastern slopes of Snowdonia National Park in Gwynedd, Wales, between about 200 m and 260 m above sea level. The reserve is underlain by coarse-grained greywacke, grit and sandstone, and is dominated by an old-growth canopy of sessile oak (Quercus petraea) and downy birch (Betula pubescens), with veteran oaks aged up to 350 years mixed with areas of coppice and younger regrowth. Pollen analysis from a small hollow in the wood shows that, over the past 1,500 years, the site underwent phases of partial canopy opening—likely managed as a grazed park in medieval and post-medieval times—followed by periods of rapid natural…