Why your tree probably does not fix carbon or produce ogygen

The other day, a friend of mine was lamenting about the cherry tree in his yard that a careless contractor had torn down to expand hhis driveway. He remembered how his children had swung from that tree, the cherries they ate and the decades of oxygen that tree had produced to improve the environment.

In my work, I very frequently am confronted with people that think that all trees and forests produce oxygen, so I decided to write down the process, in what I hope is a simple way that helps lay(wo)men understand how it works.

It is true that during its life, a tree produces oxygen and sequesters carbon, following this equation:
6CO2+6H2O->C6H12O6+6O2, which then gets transformed into the many substances that are necessary for living bodies, in which complexes of carbon and hydrogen dominate.

However, what most people don't realize is that after they die, most trees either rot away or get burned. So then the carbon fixed in the tree disintegrates and all the fixed carbon turns into carbondioxide again (very simplified: C+O2=>CO2), thus completing the socalled carbon cycle.

Most organic material of trees in the cities and along roads end up in someone's fireplace, on the city dumps or are left to rot away in the field after they fall down. When that happens, their contribution to fixing carbon and producing oxygen is ZERO.

Now that I have you thinking, what happens to the production of oxygen of all those leaves on the trees? By now, you already guessed it, after they fall off, they rot away, and the carbon accumulated in them, gets transformed into carbon dioxide, while using the oxygen from the air in the process.

With this knowledge, lets reflect a moment about those beautiful tropical forests in the Amazon, or those endless forests in Canada and Siberia. Those forests are mature, and while some young trees grow bigger and bigger, old trees become sick, die and fall down. Every year, new leaves grow, while old leaves fall off and decay. In a slower cycle, new tree trunks grow and old ones tumble and decompose. A permanent cycle of production and disintegration, in which there is no net production of oxygen and no net fixation of carbon. There are many other advantages of natural forests, but the production of oxygen and the fixation of carbon is not among them.

For those who like to think a bit further:
In cold areas, there is a permanent accumulation of organic material on the forest floor, and indeed, the material that is really permanently accumulated, has caused a net production of oxygen and fixation of carbon. This however, is an extremely slow process, and much less 1 percent of the organic material of the very northern forests gets permanently fixed in the soil. In somewhat warmer regions, where occasional forest fires sweep through the forests, no organic material gets permanently fixed into the soil, whereas in tropical rainforests, the decaying process is so fast that most of the time, under the trees, the mineral soil is exposed, showing at best a few centimetres of recently fallen leaves.
So, no green long in the Amazon. :cry:

There are a few exceptions: there are tropical forests on Sumatra, Indonesia, where peat is accumulated, but again, the total amount is so minimal, that it can only be measured over centuries.

In my opinion, one can't consider organic material permanently fixed, unless it is covered under a layer of mineral sediments. That is how the mineral coal, oil and natural gas are fixed in the earth. Only, when covered under a secure layer of sediments, are the chances remote, that they become exposed to the air again, of course, until we dig them up. Those are processes of thousands of years though.

If we plant a new forest, we speculate that that forest will remain a forest forever. That is highly questionable. But even if it does, we must assume that it will be a production forest, and that over time it will go through a permanent cycle of growth and harvesting and that a portion of its wood will eventually burn up again in the form of used wood products (newspapers, furniture, etc.) after they have lost their usefulness to us.

Still, the plantation of new forests in itself is good, as they indeed do fix carbon and produce oxygen. But we will never be able to plant as many new forests as we are now losing to deforestation in developing countries. So before we start spending money on planting new forests, we should first spend money on keeping what we have. That is much cheaper and effective, while we also protect millions of species, that we are now losing to deforestation and climate change.
I have written more about that, and I hope you can spend a few more minutes to read that, so that you understand what is the real problem for nature conservation and using forests for carbon fixation and oxygen production. Please click on:
http://www.adopt-a-ranger.org/carbon_offset.htm
If you have any questions, please ask them on this forum, and I will be happy to answer them.