Not unless you stop them rotting after they die. I’m sure there are actual experts with better proposals but turning them into charcoal/terra preta and using that as a soil growth promoter works as dies leaving wood in salt water until it ceases to be buoyant and then dumping it in the deep ocean.
You also need to prevent the resulting trees from burning or rotting, to keep the carbon they captured intact.
It was "easy" when tree trunks kept falling into ancient swamps for millennia. Right now it's not as feasible.
Log them and build things with the wood.
We're already kind of doing this. It just needs to be on a much larger scale maybe. I'm not sure of the complete process of how much CO2 is captured by a tree, so it might not make sense.
Coal comes from dead trees.
Yes. Old dead trees who's carbon has been removed for millions of years from the system. What happens when you dump a bunch more of anything into a system. Usually the system blows up.
Trees are still falling into swamps. The difference is that microbes can digest lignin/cellulose now.