had 3 soldiers and 4 goblins, and no passive wood per second. Neither in the skilltree or at the forrage stage.
Buying them should be enough to generate regular wood. If you unlock the allocation zone, that's where you can deploy different units to different forests to harvest their respected woods. You may want to try and allocate them there and see if that fixes it. That amount of units should give you like 2 wood a second roughly without additional boons...