This paper presents an embedded zerotree wavelet coding technique for the compression of arbitrarily shaped 2D objects. The wavelet decomposition is carried out with an optimized, biorthogonal, shape adaptive discrete wavelet transform (SA DWT) which performs non-expansive multiresolution decompositions of arbitrary image regions. The proposed SA DWT is defined for even-length, symmetric wavelet filters such as the 6-10 filters. The processing at region boundaries is carried out via reflection, followed by an optimization stage which requires only a few operations per boundary pixel. The computationally inexpensive optimization results in an additional performance gain of up to 0.5 dB compared to the plain reflection based scheme.