Rachel @ CRAFT points us to these amazingly detailed cut leaves by Nature’s Art, complete with a step-by-step (PDF):

Natural leaf carving is actual manual cutting and removal of a leaf’s surface to produce an art work on a leaf. The process of carving is performed by artists using tools to carefully remove the surface without cutting or removing the veins. The veins add detail into the subject matter of the carving.

The material or most common leaf used in leaf carving is the leaf of a Chinar tree. The Chinar tree is native to India, Pakistan and China. Chinar leaves have a close resemblance to maple leaves.