I think the assumption is that: 1. the tree will eventually be replaced by another tree, but more trees are being planted overall than are dying, so their numb

I think the assumption is that: 1. the tree will eventually be replaced by another tree, but more trees are being planted overall than are dying, so their numbers go up 2. the time dimension matters a lot. i.e. sequestering lots of CO2 inside trees now is still useful even if it gets released later because by then maybe technology will have improved to be less fossil fuel dependent.