A tree is a temporary store of CO2, but planting trees is not the solution to global warming even if it does help in the short term and can produce beneficial local climate effects such as increased rainfall.
Cut down swathes of forests in their prime and bulldoze them into vast landfills. In 250 million years, global warming will be sorted and there will then be vast swathes of fossilised carbon in holes in the ground and the whole cycle can start again.
Simple.