Allt y Gaer

Allt y Gaer stands in the Tywi Valley, a conifer woodland of 3.5 hectares on the northern slopes. Its special status comes from holding the largest heronry in West Wales. By 1980 over forty pairs nested here, making up seven to ten per cent of the region’s herons. Earlier herons used sites upstream at Allt y wern and in the 19th century Dinefwr Park. Disturbance during tree-felling may have driven the move to this quieter spot. The woodland is mainly mature larch, planted long ago. The thick canopy blocks most ground plants, yet fungi thrive in the deep needle litter. Spotted Toughshank, Plums and Custard, and Clouded Agaric all grow here. The site is kept undisturbed, especially from February to June when herons raise their young. Above the trees, at 350 metres, lies Grongaer, an Iron Age hillfort. The fort gives its name to the hillside, the woodland and a nearby farm. Visitors walk through quiet conifers and then climb to views over the valley and the old ramparts.