1. An apparatus for image encoding, comprising: a computer configured for receiving image data; memory coupled to said computer; and programming executable on said computer for performing steps comprising: executing transforms on received image data into the frequency domain to generate transform coefficients within a tree having a plurality of subbands; scanning of subband pairs according to a desired order; determining if a ring of zero-trees condition exists in which a zero-tree is detected at the same spatial location in at least two subbands; and generating a ring-tree symbol within an encoded image output in response to determining that the ring of zero-trees condition exists.