Nature Bulletin No. 310 June 9, 1984
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
The use of charcoal is as old as the written history of mankind. There
are many folk tales about the queer lonely men who lived in the
forests, cutting wood and converting it into charcoal. In Europe it is
still an important fuel for such purposes, for heating homes and, in
some countries, for special motors on small automobiles. As late as our
Civil War, gunpowder was made from a mixture of saltpeter, charcoal
and sulfur -- the charcoal being specifically prepared from the wood of
such trees as willow, alder and soft maple.
Until 1337, when the hotblast process was discovered, using coke
made from coal, charcoal was the only fuel that could be used in the
smelting of iron ore. Charcoal burning was an important industry and
the "colliers" who supervised the process were respected as craftsmen.
Iron making flourished in early New England but by 1750,
Pennsylvania, with its wealth of iron ore, limestone, water power and
hardwood timber for charcoal. took the lead and became the richest of
the thirteen colonies. It supplied most of the pig iron for the armies of
General Washington, and rusting cannonballs are still to be found at
the remains of some of those old charcoal-fired furnaces. In those days
the woodlands of Pennsylvania were always covered with the thin blue
haze of smoke from burning charcoal "pits" and the colliers' huts.
The best grade of charcoal was made from chestnut, oak and hickory.
Pines and other conifers were not used. It took 5-1/4 cords of wood
(672 cubic feet) to make one ton of charcoal. and two tons of charcoal
to produce one ton of pig iron. Each of the many small coldblast iron
furnaces consumed the equivalent of 50 to 75 acres of woodland per
year and that went on for over 100 years.
The trunks and limbs of trees were cut and split into 4-foot lengths
that ranged from 1-112 to 7 inches in diameter. After drying a few
months, a circular layer of these "billets' and "lapwood" was carefully
stacked. on end. over a clean level spot of ground. Other layers were
stacked over the first and sloped inward to form a large compact
rounded mound which had a chimney hole down through the center.
The whole was covered with a layer of dead leaves, old charcoal dust
and soil. After setting it afire at the top, the collier and his helper
watched it day and night while the fire gnawed its way downward
through the pile, regulating the draft so that it burned slowly, and
repairing any breaks in the outer covering as it shrank and settled.
In southern Illinois, a little north of the Ohio River near Rosiclare,
stands a ruin of one of those old iron furnaces; and north of Cairo, at
the southern edge of the Shawnee National Forest, charcoal is now
being produced in large brick kilns. Most modern charcoal, however,
is made from sawdust, wood waste and timber unsuitable for other
purposes, in big retorts which enable the recovery of by-products such
as wood tar, acetone and wood alcohol. Nowadays, most folks think of
charcoal as an expensive fuel to be purchased in paper bags for use on
picnics and barbecues, or for broiling steaks in swanky restaurants. It
makes a very hot clean fire with no smoke, fumes or ashes. and there
is no better way of cooking a good steak nor of roasting sweet corn in
its husks or "shucks", as they say in downstate Illinois. Just try that,
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Update: June 2012