"From a memory consumption (size) point of view, a Judy tree shares (does not duplicate) common digits of a key in a tree. This form of key compression is a natural outcome from using a digital tree. This would be very awkward to do in trees balanced by population and, as far as I know, has never been done. Each pointer traversed in a Judy tree points to ever smaller sub-expanses, while decoding another 8 bits of the key. (In a pure digital tree, the keys are not stored in the tree, they are inferred by position.)"