Well, I don’t know what they intended when they listed them, so this is not an answer that has any weight of rules interpretation to it.
However, I think you could say that a woodcutter is someone who moves through a wooded area and collects wood that would be most useful as fuel; they can work alone, and with no supporting facilities. A lumberjack could be someone who is engaged in taking down substantial trees, for the purpose of making timber, and would likely need to be part of an operation engaged in the same in order to work.
In a similar way, while a herdsman might be an individual who moves a group of livestock from pasture to pasture and keeps an eye on them until it is time to sell them, a rancher might need to have an established location where livestock is raised and maintained, and again might not be able to function alone as a herdsman could.
Just some thoughts.
