Futurology

But you need to cut those trees down and place them somewhere they won't rot

Sink them to the bottom of the deep ocean, but trees famously float

Leave them in deserts where the dryness will suppress rot, but damage the desert habitat

Dump them in peat bogs, but there aren't enough

Perhaps it would be best to cook them to charcoal, it releases some carbon into the atmosphere, but it would leave some solid, inedible to anything carbon that can be dumped in any old mine, but that's expensive

Also if you dump the whole trees in whatever way, you also dump whatever nutrients are in it

Yeah, just get a good ecosystem going and every now and then, collect extra decaying matter and dump it in deep landfills to further reduce carbon escape. Hopefully the pit will be deep enough to stop the decay and prevent instant (in geological terms) biogas formation.

Ok, I guess that is not very viable. Just go with normal forests then. But that won't match the predicted numbers because predictions didn't consider reduction of net Carbon -ive of the forests as they came closer to equilibrium.

We need way more trees than we previously thought, way sooner than we previously thought. Now, even more since the average temps have already increased, further changing the forest efficiency.