Thurmont in Frederick County, Maryland — The American Northeast (Mid-Atlantic)
Second Growth Forest
Look about you and notice the trees. How old are the trees in the park? Most of the trees on the mountain are less than 100 years old. The iron furnace used charcoal as a heat source. Wood made into charcoal was the only energy source known at that time which could provide enough heat to melt the iron ore.
Clearcutting the forest to feed the furnace fire was devastating. One acre of wood was needed to provide the charcoal used to heat the furnace for every 24 hours of operation. Collie-s lived in huts close to the charcoal hearths (see photo) and made charcoal from May through October. Smoke from these fires covered the mountain in a thick blue cloud during the charcoal making process. Twelve to 20 foot circular depressions which can be seen in Catoctin Mountain Park and Cunningham Falls State Park are remnants of these hearths.
During the last days of the furnace, coke made from anthracite (hard coal) replaced charcoal as fuel for iron smelting, Nature would begin the healing process of reforestation. Slowly, new growth began on the mountain in a successional series. In the first four years grasses and non-woody herbs grew. Woody shrubs and quick growing trees such as Staghorn Sumac, Red Maple, and Black Locust later appeared. A few years later, Poplar, Beech and other Maples invaded, Finally, Oaks and Hickories evolved as the climax stage of ecological succession.
Today, the trees in the park are protected and provide abundant food and shelter for wildlife such as deer, wild turkey, fox squirrel, and grouse. In addition, the forest is a watershed which helps to clean water for drinking, clear the air of pollution, produce oxygen, prevent soil erosion, and cool the air.
Erected by Catoctin Furnace Historical Society. (Marker Number 2.)
Topics. This historical marker is listed in these topic lists: Horticulture & Forestry • Industry & Commerce.
Location. This marker has been replaced by another marker nearby. It was located near 39° 35.076′ N, 77° 26.161′ W. Marker was in Thurmont, Maryland, in Frederick County. It could be reached from Catoctin Mountain Highway. Touch for map. Marker was in this post office area: Thurmont MD 21788, United States of America. Touch for directions.
Regionally, this marker was in the Washington Metropolitan Area and in Central Maryland. It was also in the American Mid-Atlantic. Globally, it was in the North Atlantic Region, North America, the Western Hemisphere, the Western World, and the Anglosphere. Historically, it found itself in what was once one of the original Thirteen Colonies and also the Antebellum South.
Other nearby markers. At least 8 other markers are within walking distance of this location: A Creek Rediscovered (a few steps from this marker); Destruction and Renewal (a few steps from this marker); A Fractured Landscape (within shouting distance of this marker); The Ingredients For Iron (within shouting distance of this marker); Walk Through History (about 400 feet away, measured in a direct line); Recreation For All (about 400 feet away); A Lost Pond (about 500 feet away); Waste Management (about 500 feet away). Touch for a list and map of all markers in Thurmont.
Other markers no longer nearby. Little Hunting Creek (was a few steps from this marker but has been replaced with another marker now near it); Slag Heaps (was about 500 feet away but has been replaced with another marker now near it).
Credits. This page was last revised on May 18, 2026. It was originally submitted on October 25, 2021, by Allen C. Browne of Silver Spring, Maryland. This page has been viewed 333 times since then and 9 times this year. Photos: 1, 2, 3. submitted on October 25, 2021, by Allen C. Browne of Silver Spring, Maryland. • Bill Pfingsten was the editor who published this page.


