Trees can keep running for 40-100 years using your figures. Governments can compulsory purchase and designate regions as wilderness or reserve, and require region appropriate planting. Perhaps to resemble former natural forest.

You can't ask people to set their thermostat 1 degree warmer every year for that 40-100 years. You can expect there to be scope for continued tree planting for decades.

Neither is a sole solution, but both are part of a holistic, reasoned and coordinated journey to carbon neutrality.