I don't understand reforestation in the sense of plant X amount of trees, and feel good about yourself. Won't this happen naturally at a similar rate if you jus

I don't understand reforestation in the sense of plant X amount of trees, and feel good about yourself. Won't this happen naturally at a similar rate if you just leave it alone? I'm pretty sure my yard would be covered in different shrubs and trees within 10 years if I just stopped tending it.