Metal-forest patterns of electroless deposits of silver and gold in thin-layer aqueous solutions were studied in connection with their chemical reactions. While the silver metal-forest with a simple redox reaction of Cu and Ag+ showed a DLA (diffusion limited aggregation)-like pattern, the gold metal-forest with a redox reaction of Pb and AuCl4- showed a DBM (dense branching morphology). The reaction mechanism of the latter was investigated by means of cyclic voltammetry, and the growth condition of the DBM is discussed.