Great looking piece Steve. I took a class several years ago on carving. We used a plunge router to remove a lot of the waste using a 1/8" or 1/4" down spiral bit. The spiral bit will give you a lot of control of the movement of the router and let you get really close to your boundary lines. For one of the carvings we had about 3 levels of carving, a tree in the fore ground, some text on the back ground, and some hills I believe in the back ground. Cutting away the waste can save a lot of wear/tear on your carving tools.
I should have that one around still, I'll snap a shot later today if I come across it, had some leaves on the tree. I recall drawing individual leaves, tear drop shaped, then using a v carve tool to out line the lines and a fish tail tool to round them off a little.