As a HUGE user of 3D terrain, woods are best handled for a hexless system as follows:
Cut a swath of Dark Green Felt or make a base and color appropriately. Place a few dollar store trees/Model Railway trees on the base.
Currently I am moving to making my bases with a small bit of metal in a corner or somewhere and making a magnetic base for the tree to 'hold it' in place. Remove tree when something moves into that area, put back when they leave. Again, I have a light green base for Light woods, and darkgreen for Heavy woods.
Part I'm having issues with right now, is making snowy bases, and trying to find a way to represent Light/Heavy for the bases :-\
**Also, best to refer to the woods as Light and Heavy as Level I/Level II is confusing as Level is usually reserved for Elevation (i.e. a Level 1 hill, a Level 2 building)