Staedtler's Wopex pencils use a new wood-based material to make them more environmentally friendly. Standard wooden pencils need a good clean piece of wood, straight, and long and wide enough to make a batch of pencils from. The wood needs to be uniform enough that the pencils will all sharpen cleanly. This all means a lot of wood is wasted, as only some of the wood in a tree is usable.
Wopex changes that by using an extruded wood-based mixture, which can use almost any pieces of wood. Because almost the whole tree can be used, there's far less waste, and far, far more pencils from each tree.
In use, Wopex pencils are just like wooden pencils, with nice clean sharpening, and a slightly heavier feel.