Peatlands

Peatlands occupy approximately one fourth of the territory of Estonia. The most widespread type of peatland in Estonia is raised bog, in which a thick layer of peat has accumulated during millennia and the plants lack contact with mineral land. The vegetation of raised bogs is dominated by sphagna, which absorb water like a sponge, thus maintaining a relatively stable water level in the bog throughout the year. Dwarf shrubs such as the marsh tea, the heather, the marsh andromeda and the cloudberry are the typical species here. In fens the peat layer is thin, fluctuations of the water level are great and the vegetation is dominated by sedges and grasses, whose roots reach the underlying mineral soil.

In transitional bogs, sphagna are gradually beginning to dominate the field layer together with sedges; the tree layer is formed by stunted white birches, and to some extent also alders, spruces and pines. The undergrowth and field layer consist of species typical of minerotrophic mobile water swamps (in wetter places); in sphagnum sites the growth conditions are suitable for species characteristic of raised bog forests.

Raised (ombrotrophic) bog forests are also pine forests but, unlike dry boreal and boreal heath forests, the trees grow on peat here, not on mineral soil. The peaty substratum often strongly hinders tree growth. The field layer is dominated by species typical of raised bogs: bog mosses or sphagna, cotton grasses, and cloudberries. Of the dwarf shrubs the more common species are the marsh tea and the bog whortleberry, and in places also the heather.

Details about this article