Peat-moss is a very important form of plant life in the boreal ecosystem and it grows in very closely-knit, thick masses. Peat-moss is often confused with mosses in general, but the latter are now classified separately with the bryophytes. Peat-moss or sphagnum species are much less numerous than mosses, but they are also less well-known and a great deal remains to be learn about them. The rusty peat-moss (Sphagnum fuscum), a common species, is found in the boreal forest and across the North American continent. It is much rarer once you get to the south of New York.
Peat-moss grows continually and its base decomposes very slowly, a process that, over the years, creates peat bogs that can be several metres deep. Since these plants can absorb 10 to 15 times their dry weight in water, a peat bog is like a giant sponge. The chemical exchanges between water and plant makes the environment acid. It is this acidity in the peat bog that ensures a very slow decomposition of organic matters and explains why mammoths and even human beings buried there centuries ago have surfaced in an excellent state of preservation. This phenomenon allowed researchers to learn about the plants that occupied the territory long ago, by studying samples of pollen taken at different depths.
However, sphagnum does not grow only in peatland. A number of the species live under the forest cover, in the water-logged undergrowth, where they begin the process of creating peat. Other species thrive in shady deciduous woodlands, but do not initiate the development of peat bogs. The most abundant species of peat-moss undergrowth in the Boreal forest is the Sphagnum girgensohnii.
The peat in our peat bogs has a considerable economic impact on horticulture. The peat-moss itself used to be, and in fact is still valued for its absorbent properties. The American Indians used it as nappies for their children and as sanitary towels for their women. This, in fact, is still done today.
The peat bogs, created by the sphagnum, take centuries to build up and are the preferred habitat of many other species of plants and animals.