Pollen analysis
Pollen analysis of the buried soil under the barrow showed that a grass-heath vegetation community dominated the summit of Fan Foel immediately prior to construction of the barrow, with hazel scrub on the lower slopes and mixed woodland with oak especially at lower levels. Charcoal was also found in the buried soil, and may indicate burning to improve soil cultivation, or alternatively, local use of fire as a beacon, as suggested by the name of the range of the Brecon Beacons. Both Pen y Fan and Corn Du are visible on the horizon about away.