Ambient Occlusion

I have the basics with ambient occlusion.
I was wondering say for plants.
In my case the plants are usually lit by the environment lighting.
So the occlusion could be generated off the texture, normal etc…or even hand painted areas…
Should I be baking occlusion also?
Or is baking occlusion basically for a scene lit with custom lighting mapping, Shadow maps etc.?
Where the scene is not using environment lighting.