The Woodcutter is the person who starts the production of Timber. He cuts trees and he produces Tree Trunks, which can be processed to Timber in a Sawmill. Timber is really important in the game, because you need it to build houses and create weapons.
The Woodcutter cuts trees, but as soon as all trees have been cut, he will plant new trees. It takes a while before those trees start to grow, it takes usually 10 minutes to grow an "adult" tree.
It's useful to have 2-3 Woodcutter's in your village, so you won't run out of Tree Trunks, Timber. If you run out of Tree Trunks, you won't be able to produce any Timber, which means that you can't build any houses or create weapons anymore. If you run out of Tree Trunks, you have lost.
To train a Woodcutter, you will need: