They take up a lot of space at scale though.
Mass tree planting is like doing a massive, massive migration. You can't just stick seedlings in the ground arbitrarily and expect a stand of trees to sustain itself 'cause "nature"... the successful processes like the Miyawaki method require planning, community investment, sustained work for ~5 years, etc.
https://daily.jstor.org/the-miyawaki-method-a-better-way-to-...
After the trees have grown, you need to harvest them and - somehow - make sure they don't rot and return the CO2 to the atmosphere.
Finding space for that is what I mean by "take up space at scale".