Because the tree would need to grow 100x as big. People often forget, that the carbon needs to go somewhere and in a tree that is mostly the wood.
A fully grown forest is just full and can’t take up more CO2 unless you take some wood out.
That wood need to be used in construction or turned into charcoal and buried to make sure it can’t be turned back into CO2 by rotting.
Because the tree would need to grow 100x as big. People often forget, that the carbon needs to go somewhere and in a tree that is mostly the wood.
A fully grown forest is just full and can’t take up more CO2 unless you take some wood out. That wood need to be used in construction or turned into charcoal and buried to make sure it can’t be turned back into CO2 by rotting.