While wildfires have threatened animals and residents in recent years, they have been a part of Earth’s processes for millions of years without human intervention. Scientists have discovered the world’s oldest wildfires thanks to 430-million-year-old charcoal deposits in Wales and Poland. They reveal much about what life was like on Earth during the Silurian period. The wildfires would have burnt through fairly short vegetation, with the occasional knee- or waist-high plant thrown in for good measure. Plant life would have relied substantially on the water to reproduce back then and would have been unlikely to appear in dry areas.
According to the researchers, the ancient fungus Prototaxites would have dominated the environment rather than trees. Though the fungus’s exact size is unknown, it is said to have grown to almost 30 feet.
Wildfires require fuel (plants), an ignition source (here, lightning strikes), and enough oxygen to burn to survive. According to the researchers, the ability of the fires to spread and leave charcoal deposits indicates that Earth’s atmospheric oxygen levels were at least 16 percent. That level is now at 21% but has fluctuated drastically throughout Earth’s history.
According to the findings, atmospheric oxygen levels 430 million years ago may have been as high as 21 percent or higher.
The findings were reported in the journal Geology.
Paleobotanist Ian Glasspool of Colby College in Maine said that it looks like their evidence of fire matches closely with the evidence of the earliest terrestrial plant macrofossils. As soon as there’s fuel, at least in the form of plant macrofossils, a wildfire breaks out almost instantly, added Glasspool.
All of this knowledge is important to paleontologists. According to the theory, increased plant life and photosynthesis would have contributed more to the oxygen cycle around the time of the wildfires. Understanding the specifics of that oxygen cycle across time gives scientists a clearer sense of how life would have evolved.
The Silurian terrain required enough vegetation to propagate wildfires and leave a record of that blaze said Colby College paleontologist Robert Gastaldo. “At points in time that we’re sampling windows of, there was enough biomass around to be able to provide us with a record of a wildfire that we can identify and use to pinpoint the vegetation and process in time,” added Gastaldo.
The two sites the researchers chose for their analyses would have been on the ancient continents of Avalonia and Baltica during the wildfires. This discovery not only helps to break the previous record for the oldest wildfire on record by 10 million years, but it also emphasizes the importance of wildfire study in chronicling Earth’s history.
