Mountain Betula in Varrio I.

In Regio subalpina of Varrio the mountain birches dominate. Is the birch a species of its own? Or is it a subspecies of Betula pubescens? For time to time the opinion of a species of its own, that is Betula tortuosa auct., has had its supporters. Currently the mountain birch is believed to be subspecies, that is Betula pubescens ssp. czerepanovii (N.I. Orlova) Hämet-Ahti. - Behind in the photo Kotovaara; the sun is shining from north.