I’ve asked before that the default worker allocation for Work Camps to be 1 rather than 2, because unless you are on a very heavily forested map, 2 workers will defuse the zone of trees, and thus not be sustainable.
However, a better solution for this would simply to let the player select the size of the work radius (and similarly for the Hunter’s Cabin and Forager’s Shack).
I don’t know how others feel about this, but I have no problem with planting trees to be harvested in the zone of a work camp. It doesn’t cost me much at this point – I have a goodly income and I don’t mind spending the time planting. I keep a good level of wood to supply building, plank-making, firewood, and the 3 charcoal factories I maintain because I have zero coal deposits. Other people’s mileage will vary, of course.
The best solution is to have a forester to plant and harvest trees.