No, because as soon as a tree is dead it will begin to rot and decompose (there's fungi everywhere in the air that is just waiting for a piece of juicy fresh tree to digest), thereby releasing CO2, methane and other decomposition gases.
The only way to sequester CO2 using trees is keeping the trees alive (or blasting them with chemicals to prevent rotting).
If you bury the trees reasonably deep, that CO2 takes a very long time to get to the surface (like tens of thousands of years) so it’s good enough for our purposes.
You can also weigh it down and sink it to the bottom of oceans that don't have wood eating organisms. The Baltic and the Black Sea are the ones I know.
But of course, the solution you mention is the simplest: Treat the wood with one of the several known ways to make it not break down, and leave it in big piles somewhere.
I mean, it worked for the Carboniferous, until some cheeky fungus figured out how to digest lignin. But we had a nice 60 million year run, and got lots of useful hydrocarbons out of it, so hey!
Truly bioengineering at a galactic scale. In a hundred million years, geological processes will have turned your polymers into some cool new exotic fuel source.
The only way to sequester CO2 using trees is keeping the trees alive (or blasting them with chemicals to prevent rotting).