Charcoal is more volume efficient because that's nearly pure carbon, and high char charcoal has a substrate-to-charcoal efficiency of 90 to 95%. Most of the lost weight is oxygen and hydrogen.
The important thing is that it's a net improvement. If you can make that tree grow, harvest and store it in a hole for even half the carbon emission handling the tree takes you basically take out 1 tree worth of carbon for every 2 trees you plant for off setting carbon emissions.
You also don't need a coal mine to stuff those logs. Any hole will do, so long as you plug the hole after you're done. I mean, take an empty open pit mine, point a conveyor belt into the damn thing and just keep the to be sequestered carbon coming.
The important thing is that it's a net improvement. If you can make that tree grow, harvest and store it in a hole for even half the carbon emission handling the tree takes you basically take out 1 tree worth of carbon for every 2 trees you plant for off setting carbon emissions.
You also don't need a coal mine to stuff those logs. Any hole will do, so long as you plug the hole after you're done. I mean, take an empty open pit mine, point a conveyor belt into the damn thing and just keep the to be sequestered carbon coming.