This study explored a possibility that leaf silicious trichomes slow down leaf mass loss by soil meso- and macrofauna. We focused on closely related Moraceae tree species (Broussonetia papyrifera and Morus australis) with different leaf trichome densities. First, we conducted microscopic analyses of leaf trichomes and investigated nine other leaf traits. We then performed a 25-day decomposition experiment with bags of different mesh sizes that excluded and included meso- and macrofauna. Broussonetia papyrifera exhibited a 150-fold higher silicious trichome density on the lower leaf surface than M. australis. The carbon-to-nitrogen ratio was significantly lower in B. papyrifera than M. australis. In decomposition, the ash-free mass loss of B. papyrifera was significantly higher than that of M. australis in the <0.2-mm mesh bag. In the 5-mm mesh bag, however, the ash-free mass loss of B. papyrifera was significantly lower than that of M. australis. Despite rich nutrient quality of B. papyrifera leaves, leaf decomposition of B. papyrifera with greater trichome densities was slower than that of M. australis only in the 5-mm mesh bag that permitted the entry of meso- and macrofauna. This suggests a suppressive effect of leaf silicious trichomes on decomposition by the large decomposers.