The first Forests

Over 400 million years ago the first plants came out of the ocean on to the land. About 15 million years later, the first forests formed. They played a strong role in further reducing the carbon dioxide content of the atmosphere – and their deep roots enhanced weathering, whereby CO2 is also bound up. To the degree that the vegetation cover spread out, the carbon dioxide content of the atmosphere sank and the oxygen content rose.


These plants had leaves and a stem that became thicker over the years. They formed the main component of the first woods. Archaeopteris is considered to be the first tree and is therefore a similar specialty to Archaeopteryx, the first bird. The fossil shown here is about 370 million years old.


The first organic soils were formed as the first plants came onto the land, thus over 400 million  years ago. Previously there were only rocks, gravel, and sand everywhere.
Soils are important CO2 storage reservoirs. Through clearing of forests we are currently setting free CO2 from soils.

Chapter 5