Large-scale tree planting can remove some CO2 from the atmosphere, but nowhere near as much as humans add by extracting and burning fossil fuels. See https://skepticalscience.com/1-trillion-trees-impact.html for a detailed assessment of what this looks like.
The IPCC has a chart showing what actions need to be taken over the next few years. Afforestation is one piece of many things, all of which we need to do.
I have been planting hybrid poplars and willows for three years. I’m bad at it, and lazy. So I basically just walk out to the semi-swamp behind my house and push sticks in the ground. I now have about 15 trees, 8ft to 26ft, and I’m slowly turning my backyard into a shady alcove.
Unfortunately the hybrid poplar only lives for 30 years, but you can plant longer living trees (maples, pines, oaks) while the initial batch is growing. Then bury the wood of the poplars to sequester the carbon.