For sure the carbon is good for plants, but nowadays there is too much carbon in the air and not enough in the soil, where it helps plants to grow because it also help every animals living in the ground to live. But here the agricultural industry cause another problem destroying ground life with pesticides.

When politicians speak about carbon neutral They mean 0 carbon dioxide gae emission, and one of the best way to reach it is as you said, planting more trees and improve the agriculture to catch the carbon in the air and keep it in the ground.

The goal isn't to totally remove carbon emissions but to balance it with catching carbon. The documentary kiss the ground speaks about that !