Up by the Devil’s Dyke (Trou du Diable) near the Domain Solvay, whilst measuring trees for a future martelage, there were two birch cousins side by side in conference, the hanging and the hairy.
Betula pendula is the one we instinctively recognise, the Silver Birch, with its peeling white bark and drooping twigs. Betula pubescens, by contrast, has softly hairy young shoots and bark that is less showy, more uniform, duller, greyer.
Both are pioneer species, opportunists, yet it felt odd to find them growing side by side. Pendula prefers open, drier aspects, while pubescens damper, heavier soils. Borderlines were indicated. Looking about, there was a sewage farm down in the valley, and open grassland beyond the nearby forest edge in the other direction. We were betwixt and between, in betulaland.