Nature Bulletin No. 523-A March 30, 1974
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
hundreds of years in Ireland, as in parts of northern Europe and
Russia, the only fuel available to poor people has been Peat. From
partially drained bogs they cut it in slabs that are piled and sun-dried.
These smolder and glow continuously on the hearth of each cottage,
never naming high but giving off steady heat and a characteristic odor.
Peat is a somewhat fibrous and spongy material consisting mostly of
partially decayed vegetation which accumulated, for centuries or even
thousands of years, underwater or in waterlogged places such as
swamps and bogs. It represents the first step in the making of coal.
During millions of years, vast beds of peat were compressed and
gradually transformed into the various kinds of coal now mined from
beneath the earth's surface.
There are two main types. One is "highmoor" or sphagnum peat formed
from several species of sphagnum or peat moss. The great muskeg
swamps in Canada are spongy treeless areas covered with sphagnum
mosses and underlaid with that kind of peat. The other type, "lowmoor"
peat, is derived largely from sedges, reeds cattails, pondweeds and
other aquatic plants. Such vegetation, as it dies each year and is covered
with stagnant water, decays very slowly due to lack of oxygen. Well
preserved plant remains -- pollen, seeds, leaves, stems, roots and pieces
of wood -- and animal bones, are commonly found in deep beds of
The principal uses of peat in the United States are for agricultural and
landscaping purposes. Being lean in nitrogen, phosphorus and potash, it
is not much good as a fertilizer but, being fibrous and spongy, has other
valuable properties. Lowmoor peat can absorb and hold from 3 to 8
times their own weight of water; sphagnum peat can hold far more.
When mixed with fine "tight" soils, peat improves their water-holding
ability and also their physical structure -- their tilth. If manure or other
fertilizer and ground limestone are added, peat makes the fertilizer
more effective, soil water more available, and helps plants, notably
lawn grasses, to withstand droughts. Acid peat, especially sphagnum,
are used without limestone for acid-loving plants such as
so absorbent, peat is used as litter in chicken houses and as
bedding in barns where it becomes rich with manure and very valuable
for farmland. Another use is as a conditioner to keep commercial
fertilizers from drying out and becoming sticky or caked. Sphagnum
moss is used extensively in greenhouses, gardens and nurseries for the
propagation, growing and shipping of plants. Muck soils -- in which
peat has become highly decomposed and usually mixed with alluvial
deposits of mineral soil -- are extensively cultivated to grow onions,
potatoes, celery, mint, and other crops.
There are extensive deposits of peat in Malaya, Australia and parts of
Africa. The great Dismal Swamp in Virginia and North Carolina is a
peat bog. Largely, however, they are found in northern glaciated
regions where the most undrained or poorly drained depressions occur.
The USSR (Russia) has by far the greatest total area of peat, followed
by Finland, Canada, Sweden, the United States, Germany, Great
Britain, Ireland and Norway. About half of the U.S. deposits are in
northern Minnesota; most of the remainder are in Wisconsin, Michigan
In Cook County, peat deposits lie beneath McGinnis and other sloughs
in the Palos region, The largest are in the Skokie and Sag valleys where,
from time to time, dangerous peat fires have burned and smoldered for
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Update: June 2012