Stone kilns used to produce charcoal in the 1800’s still visible in Michigan today
During the height of Michigan’s iron boom, charcoal was the main fuel used to fire the blast furnaces to smelt iron.
If you’ve ever sat around a campfire or fireplace, you know that wood, especially seasoned firewood, readily burns when ignited. What you may not realize is that slowly heated wood changes into a material that burns longer and hotter than firewood. This material is charcoal, and has been used for a variety of reasons for about 5,500 years. In an effort to highlight historic uses of Michigan forests, Michigan State University Extension researched the use of charcoal in iron production during the 1800’s.
Since ancient times, charcoal has been made by slow burning logs under a man-made earthen mound, called a kiln. The design varies with culture and available materials, but the basic idea was to carefully arrange logs in a large pile so that heat would be uniformly distributed to all logs. The pile was covered with soil, sod, and other green vegetation leaving a few holes at the base and near the top of the mound. These holes were used to limit the amount of oxygen as too much oxygen would cause the logs to catch fire which ruins charcoal. Instead, the goal was to create a smoldering fire that vaporizes the moisture and other gases from the logs, leaving behind the carbon rich material we know as charcoal.
The advent of stone kilns
In the 1800s, more permanent kilns made of stone were created to replace the earthen kilns, which could take weeks to construct. Stone kilns could also be used repeatedly, unlike the earthen kilns that could be used only once. Stone kilns were typically shaped like the earthen kilns, and produce charcoal in days, rather than the weeks it took to produce charcoal in mounds. Stone kilns were typically constructed near industrial sites in areas surrounded by forests.
Kilns in Michigan
In Michigan, stone kilns were constructed on an industrial scale to fuel smelting operations. Smelting is the process of heating ore, or rock containing metal, to such high temperatures that the metal is melted and separated from the minerals in the rock. A blast furnace, initially fueled by charcoal, provided heat. Both iron and copper were smelted in Michigan, at lakeside locations convenient for shipping the metal to other localities.
Kilns used to make charcoal in the late 1800’s are still visible in the Upper Peninsula, near Munising and elsewhere. At The Rock Kilns Historic Site, on the Hiawatha National Forest 12 kilns are still standing. These kilns, made of sandstone masonry, operated from 1879-1896 to produce charcoal for blast furnaces used to smelt iron ore in Marquette County. Iron production required a tremendous amount of charcoal during the late 1800’s; the Rock Kilns were just one of the charcoal manufacturing facilities supplying the 23 blast furnaces in the Upper Peninsula.
Between 1870 and 1945, the Upper Peninsula’s iron industry produced nearly two million tons of iron, used in the manufacture of railroad cars and locomotives. While coal was used to heat the blast furnaces during the latter half of this era due to the shortage of hardwood trees, charcoal production had a tremendous effect on the forests in the Upper Peninsula. The charcoal industry cut over roughly 447 square miles forest, equal to 285,860 acres, by hand, over 75 years. These forests were comprised mainly of beech, maple and oak trees which have grown back following the era of charcoal production.
Kilns may also be found at Fayette State Park, an historic, well preserved iron manufacturing community located near Garden, MI. Michigan is also the birthplace of Kingsford Charcoal.
In the 1920’s, Henry Ford built a chemical plant to reclaim the bits of wood leftover from the manufacture of wood panels for automobiles. Charcoal briquettes were one of the products. Originally called “Ford Charcoal,” the company, based in Kingsford, MI, eventually adopted the towns’ moniker after Ford sold the business to a group of local businessmen in the early 1950’s.