What is the truth about the fires in southern Illinois 226 years ago?

W. McClain is a botanist at Illinois State University who is well versed in the history of fires in Illinois and surrounding areas. By studying burn marks in the trunks of star oak trees, he reconstructed the fire history of southern Illinois over a 226-year period. The findings show that the ecological environment was permanently changed after the first European settlers banned the practice of forest burning here.

Picture: Fire traces in the trunk of the star oak tree

The heartwood of the star oak tree is extremely strong, which allows them to regain their vitality after suffering severe fires. The scars preserved in the body provided very valuable information for McClain's research. McClain counted growth rings and burn marks on the trunks of 36 ancient oak trees. Most of the fires he observed in tree trunks were documented, and the vast majority were started by Indians.

Before the arrival of European immigrants, the native people of Illinois would set fire to the forest almost every year, and the forests of Hamilton County would have a fire about once every 2 to 3 years. Such forest burning maintained the balance between grassland and woodland areas until the late 19th century. When European immigrants arrived, they banned forest burning, resulting in the expansion of forest land and the shrinkage of grassland. McClain found through research that there were more than 100 fires in Hamilton County from 1770 to 1996. There was about one fire every two years before 1850, but there was no fire between 1850 and 1885, and after 1885 , the fire reappeared. Small fires help improve livestock quality, visibility while hunting and reduce the amount of flammable brush. However, after the fire-free period from 1850 to 1885, the forest became prosperous and gloomy, and the open areas in the forest disappeared. Due to its slow growth rate and lack of sunlight, the star oak was at a disadvantage in the ecological niche competition and gradually died. Only those strong of star oaks survived. The harmonious and stable star oak forest has existed here for hundreds of thousands of years. However, just 30 years of fire-free period changed everything. Researchers say that fire has played a great role in the ecological balance here.