You would need to either bury it in a way that it won't be decomposed by microbes. Anaerobic digestion produces methane which is ~83x worse than CO2 as a greenhouse gas.

The alternative is to gasify it, and produce biochar (a.k.a terra preta), a form of carbon that is mixed with the soil to improve it's nutrient and water retention, friability and microbial activity. Biochar is theorized to be stable for 10k years in the soil.

Same way you dispose regular garbage, which has same challenges.

I went to the tour of recycling plant, and as part of the tour they told us what happens with Seattle garbage: they excavate a pit, line it up with plastic, put garbage in, cover it with plastic, put soil on top. Without supply of oxygen it basically stays there almost forever. They cut a carrot with was in such pit for 10 years. It was black on the outside, but still orange inside!

Anyway, put trees in such pits, and you have carbon capture!

Doesn’t release nearly as much as burning it.