Weconsidertheproblem of optimal, data-dependentzerotree designfor use in weighted universal zerotree codes for image compression.A weighted universalzerotree code (WUZC) is a data compression system that replaces the single, data-independent zerotree of Said and Pearlman with an optimal collection of zerotreesfor good image coding performance acrossa wide variety of possible sources. We briefly describe the weighted universal zerotree encoding and design algorithms but focus primarily on the problem of optimal, data-dependent zerotree design. We demonstratethepe$ormance of theproposed algorithm by comparing, at a variety of target rates, the pe~ormance of a Said-Pearlmanstyle code using the standard zerotree to the pe$ormance of the same code using a zerotree designed with our algorithm. The comparison is made without entropy coding. The proposed zerotree design algorithm achieves, on a collection of combined text and grayscale images, up to 4 dB performance improvementover a Said-Pea...