The Swedish mountains are surrounded by large coniferous forests. Just below the timber line, altitude 800m, there are big stands of birch. The timber line is not a fixed level but differs with climate, forestry and other human activities. During the warm period following the most recent ice age the level was 200 m higher than today.
Mountain birch forests
Just below the timber line are large mountain birch forests. They differ much in size. The eastern slopes of the mountain range have a warmer climate. The width of the birch forests can here be as little as 10 meters in altitude and there can be mixed forests all the way up to the timberline. In the western mountain area, with its colder climate, the birch forests grow many hundred altitude meters above the conifers. In the far north, between Karesuando and Torne Träsk, the largest Swedish birch forest covers more than a thousand square kilometers.
The most common tree in these forests is the mountain birch, a small and gnarled tree. It is not a species of its own but a subspecies of Betula pubescens, one of the two Swedish varieties of birch. There are also aspen, mountain ash, bird cherry, alder, sallow and other willows. In regions with less snow the trees grow straight and the------is usually------seeds. Where the winters are snowy trees are often clones with stems of different ages growing from one root, looking more like shrubs.
Mountain coniferous forests
Mountain coniferous forests grow close to the mountains, in remote areas not suitable for forestry. That is why they are the sites for our last large virgin forests. Spruces 300 years old and pines 400-600 years of age are often found here.The character of these forests varies depending on climate and soil fertility. In Jämtland and southern Lapland spruce is the dominating species, in Dalarna, Härjedalen and in the Kiruna Mountains it is the pine