The ubac - i.e. the north facing and therefore in the shaded slope - of the Lac de Serre-Ponçon is marked by a significant forest cover, particularly west of Pic de Morgon to the narrow Boscodon valley. The deciduous woods descend down the slope to the shore of the lake, giving way to Scots pines and larches aloft. The rare alluvial cones devoid of vegetation welcome villages or tourist developments.