Brazilian Arbor Day

Data / date: 21/09/11 Sem comentarios / No Comments

Setemper 21st is Arbor Day in Brazil. Good reason to know more about the first trees that appeared on earth and made life possible on our planet. The first tree or one among the first  was Archaeopteris. It absorbed carbon dioxide  (CO ²) from the atmosphere and with its strong roots dug it into the soil, over millions of years ago .

The Archaepteris prepared the ground for smaller plants. The leaves protected the newley formed soil from erosion, rain and wind. When leaves fell, they decomposed  and fertilized the soil.  Plants debris went into the water courses promoting plankton which also absorbed CO ² from the atmosphere.

Just as we eat vegetables, the first trees fed on carbon dioxide. The amount of CO ² in the Earth’s atmosphere diminished and temperatures in the earth began to fall because CO2 is a greenhouse gas and it was trapped in soil and trees.

Large animals that once lived on the water where the temperatures were cooler started to go to the land. Another positive effect of  trees’ emergence was  an increase of the ozone layer. The animals could stay on earth because the ozone layer functioned as a protective shield against ultraviolet radiation that  in high doses can be deadly. Producing more oxygen in the atmosphere, Archaeopteris allowed plants and other small animals to breathe. This gave rise to vertebrates 400 million years ago.

The Archaeopteris no longer exists, but on Braziian Arbor Day we remember it and  its most needed gift on Eath: oxygen!