That is what I've always told the apprentices.
Now you get a try at playing God.
It is excellent work for new apprentices.
They learn about trees, about making decisions and most of all, get a lot of hours of non-dangerous chainsaw work in.
One does, of course, need to keep a very close eye on them, to ensure they thin correctly.
You take out the unwanted species, the trees that have already lost the race and gone thin and too tall with no crown, the ones with growth defects like co-dominant stems and the too vigorous ones, that will end up dominating the lesser ones.
Then you try to end up with an evenly spaced lot, where the spacing fits their age.
In mixed stands, one has a mental list of which species are most desirable, and aims to preserve as many of those as possible, if they are healthy and fit te above criteria.
Which species that are desirable varies with the terrain type, of couse.
So, all in all, it is a bit of a puzzle, but with practice it becomes easy.
When I started 40 years ago, it was paid by the acre, today it is paid by the hour.
I liked the former better.
Mathias, our present one ( Who is finished in a couple of months and will then become our employee instead of our apprentice) did 3 months solid of it in the beginning.
At first, he was leery about the saw, in the end, it was an extended part of himself and he could sharpen and maintain it.
It is great for building confidence in cutting and felling, since the trees are small enough that they are not dangerous.