Betula pubescens ssp. czerepanovii
The mountain birch is an important tree precisely because it grows even up by the tree line. The mountain birch is a subspecies of the pubescent birch. It thrives in the northern fell region, and, earlier, it was considered a separate species. As a result of the rough conditions – especially the wind – of the winter, the mountain birch is often just two metres high and twisty and has several trunks. It forms the timber line in the Fennoscandian fell region from Southern Norway to the Kola Peninsula. This is rare, as the timber line is usually formed by the spruce. Presumably, the mountain birch is a hybrid of the pubescent and dwarf birches that was produced on the Norwegian coast towards the end of the Ice Age. The genotype of the dwarf birch shows in the shape of the mountain birch but also in the red colours it gets in the autumn.