Not always is planting necessary if you're lucky enough to get 'natural' seedlings to germinate & survy in the forest. Here we have a small opening of a few hundred square meters in
an old spruce stand and some vigorous seedlings occupying the free space. It is considered that through silvicultural measures we're able to gain control over natural regeneration. How much is really 'in our hands / controlable' depends a lot on the species & site.