Pine is the only tree that can tolerate the acid water and lack of nutrients that are typical in mature bogs. Wetlands in which peat has accumulated are widespread in formerly glaciated regions of northern Eurasia, the northern United States, and Canada. In regions with abundant precipitation, little evaporation, and slight runoff, various kinds of swamps, marshes, fens, and bogs may form. All these English words are united under the general term mire nowadays. Some of these words were adopted from Sami language, including the terms tundra, aapa and palsa , which are used internationally in ecological research now.
Mires can form in two general ways.
Infilling former lake or estuary basin. Slow sediment buildup combined with growth of aquatic vegetation is the natural progression for small lakes and shallow estuaries. This is the most common means for initiating mire development. Rising ground water to the surface. This process, called paludification , may take place when rates of precipitation or evaporation change so that ground water rises to the surface.