Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow. When ancient clubmosses in the family Lycopodiacaea were growing in what is now the coal fields of West Virginia, over 300 million years ago during the Carboniferous period the weather was much warmer and carbon dioxide levels vastly greater than today. Sometimes carbon dioxide is a limiting factor in plant growth – the ancient relatives of today’s clubmosses, plants like running cedar, grew to enormous heights of over 100 feet in those humid, warm swampy conditions.
Plant growth was so dramatic and the amount of carbon that was converted to vegetative tissues so enormous that carbon dioxide levels actually decreased and the relative percentage of oxygen in the atmosphere increased measurably. When these plants died they were buried in wet, swampy landscapes that hindered decay and rot; just the right conditions to form peat bogs that eventually became deposits of coal.