There is only one way to permanently remove carbon from the atmosphere, and that's to launch it off the earth and onto a path where it could never make it back. Everything else will store carbon for a while, before eventually releasing it again
A forest stores lots of carbon while it exists - there's cycles of trees dying and releasing carbon, and new trees taking their place absorbing carbon, but there is a steady state change in terms of carbon in the trees that currently exist. The carbon is only released by deforesting the area again
There are many things between forest and space launch. If you inject the CO2 underground at a reasonable rate, you can get it to bind to rock, chemically changing that rock. It might eventually find its way back to the atmosphere, but on geological timescales. If you sink kelp to the bottom of the ocean, that also effectively sequesters it.
A forest stores lots of carbon while it exists - there's cycles of trees dying and releasing carbon, and new trees taking their place absorbing carbon, but there is a steady state change in terms of carbon in the trees that currently exist. The carbon is only released by deforesting the area again