Originally Posted by
dublinpilot
So, how much C02 does a tree remove per annumn?
That depends how much it grows. But you should not see trees as being removers of atmospheric CO2.
A tree converts CO2 and water into glucose and oxygen (and water again...). Here's the (simplified) forumula:
6 CO2 + 12 H2O + light → C6H12O6 + 6 O2 + 6 H2O
The glucose is then used to make the various structural bits of the tree, such as cellulose, and it is also used as the tree's source of energy for its cellular respiration. During this latter process it is broken down to form CO2 once again. So, while the tree is alive and growing it absorbs CO2 from the atmosphere. But once it dies, it decomposes and all the organic material (i.e. the molecules that contain carbon) are broken down to produce CO2 and perhaps CH4 (methane, another greenhouse gas). A tree is a temporary store of CO2, but planting trees is not the solution to global warming even if it does help in the short term and can produce beneficial local climate effects such as increased rainfall.