Mountain birch and mountain birch woodland in NW Europe
A very pronounced feature of Northwest European vegetation is the climax mountain birch woodland that is widely covering the slopes of mountains and often forming altitudinal timberline. Throughout most of the northern hemisphere birches (Betula) are species of second-growth forests, and both the horizontal and the altitudinal timberlines are normally formed by coniferous tree species rather than broad-leaved trees. In the following a brief review is given in order to clarify the position of the mountain birch woodland from the points of view of phytogeography and phytosociology, including some reconsiderations of the taxonomy of the mountain birch Betula pubescens subsp. czerepanovii (Orlova) Hämet-Ahti, comb. nova.