Lesson 1: Gas Exchange

Now that we understand how the various parts of a forest ecosystem interact, it is time to explore the specific role of trees and forest plants.
Where exactly do trees fit into the big picture?
How do they relate to all the other parts of the forest?

In this course we have already explored the vital life processes of trees and plants, such as photosynthesis, respiration, transport of water and nutrients, and reproduction. These functions not only maintain the individual plants, they also serve to maintain the entire forest ecosystem. The environmental services that trees provide are described below.

Earlier in the course, we learned that trees exchange gases. They take in carbon dioxide that is released into the air by organisms or through the burning of wood and fossil fuels. In return, trees and plants release oxygen that is essential to the life of all animals. By removing carbon dioxide from the air, trees and plants also reduce global warming.

In this example of the carbon cycle, plants take carbon dioxide from the air and use it to make food.  Animals then use the food and carbon is stored in their bodies or released as CO2 through respiration. 
One of the most important elements to life on earth is carbon. 
Carbon is used in many processes and is often connected to the Oxygen cycle.

In this example of the oxygen cycle, you can see how oxygen is cycled by plants and animals. 
Plants create oxygen through photosynthesis; the animals breathe in the oxygen and breathe out the carbon dioxide.  The plant can then take in the carbon dioxide and the cycle is complete. 
The oxygen cycle is interconnected with the carbon cycle.