SCIENTISTS DISCOVER EVIDENCE FOR THE EARLIEST WILDFIRE
29 April 2004 - Cardiff University

The charred fossils, with exceptional three-dimensionally preserved cells, indicate that oxygen levels over 419 million years ago were high enough to cause wildfire, a naturally occurring fire that spreads across land uncontrollably.

Although usually associated with trees, this shows that wildfire started when land vegetation was only a few centimetres high.

Previously, it was believed that wildfire could be dated back to Late Devonian times, about 50 million years later.

Co-author of the paper, Professor Dianne Edwards, Head of the School of Earth, Ocean and Planetary Science said: "The probable cause is a lightning strike, suggesting that vegetation and litter were dry enough to catch fire and become charred. The climate at the time was tropical with seasonal aridity. The debate concerns oxygen levels in the atmosphere; to cause fire, it would have had to be a minimum of 12 to 13% "

In late Silurian times, twice as long-ago as the Jurassic period, the now Welsh Borderland was a coastal plain traversed by rivers with the plants colonising wetter areas, at Ludlow these being near the sea.

The 3D charcoal preserved plants indicate the importance in determining the functioning of early land plants, and the reconstruction of ancient ecosystems.

The research findings Charcoal in the Silurian as earliest evidence of wildfire written by Ian Glasspool, Dianne Edwards and Lindsey Axe is published in the May issue of Geology.

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