I'm sure it's been mentioned elsewhere here already by someone, but I've always thought that converting felled 'sequestration stock' to bio-char and making terra preta out of it would be win-win-win, as it could then be used to improve desertified land.

As much as CO2 emissions befear me, so too does increasingly poor topsoil, globally.

- ed

I'm not even sure we'd need to wait for trees to mature either - we just need work with whatever plant absorbs the most CO2. Perhaps algae, even?