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.
It was proposed as part of the Green New Deal but hasn’t been able to meaningful funding through the Senate. Too many Republicans working with a handful of bought-off Democrats
I didn’t know that! Neat. I hope it stays a part of the conversation.