– If trees release the carbon again that they have absorbed throughout their life, when they die, why do we even plant trees then?
In: Biology
The idea is to not let them die.
But besides that, they do a lot more than just hog carbon. They produce some oxygen, they help the water cycle (if you look at places where there’s heavy deforestation you’ll see lower rainfall amounts), they help soil keep nutrients for other life, they provide food for animals including us.
They don’t release it all at once. They store it in different carbon molecules that mostly get broken down by decomposers and end up back in the soil. Sure some of it gets into the atmosphere via respiration of some of the decomposers but most of it goes into the soil.
This is a system of equilibrium. The more trees are currently alive (or, more accurately, the more raw wood matter is currently in existence), the less CO2 is in the atmosphere.
By reducing the total amount of wood matter, we add CO2. By increasing it, we remove CO2.
Coal was largely formed by wood matter which was never able to convert back to CO2 and got trapped underground. This means that every tree’s worth of coal we have burned becomes a tree’s worth of wood matter that must now be sustained.
Additionally, not all wood matter is ‘recycled’ into CO2. Wood which becomes paper or houses or what have you remains in its wooden state and does not become CO2.
This is to say that renewable wood farming is essentially carbon capture.
For two main reasons, already evoked but separately in the thread:
1. throughout their entire lifespan, they consume CO2 from the atmosphere _and_ release O2 back to the atmosphere. It is a net positive effect.
2. When trees die, they do release carbon, but the majority is in the form of complex carbohydrates that go into the ground, and not CO2.
This only regards the carbon emissions. Overall, trees have many other critically important roles to the balance of the ecosystem.
Mass deforestation can result in large releases of CO2 but that wouldn’t compare to the amount the trees processed through photosynthesis during their lives. Also, planting new trees as soon as possible is important for many reasons such as replacing animal habitats, replacing the lost oxygen that the trees create, and preventing erosion which can lead to river and lake sediment pollution and desertification.
the trees don’t automatically release all carbon at once. Lots of it is in the wood of the trees.
Wooden logs keep carbon contained after the tree is dead until the wood is burned or rots away.
There are ways to sequester carbon more permanently than trees that only last for a few decades. Peat can keep much more carbon per area contained and does so for millennia. A bog may not loo as nice as a forest, but since stuff that falls in the bog doesn’t decay it is a much more effective carbon capture tool.
Trees work also the trick is that you constantly have the replace dead trees with new ones to keep things up. (Since trees live for decades or centuries in some cases and this process happens naturally if you set things up right this is not as big an issue as it may seem.)
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