Coarse woody debris (CWD) mass dynamics in three temperate natural forests, dominated by Quercus mongolica, Abies holophylla, and Pinus densiflora, were studied for 5 to 8 years in a Korea National Long-Term Ecological Research (KNLTER) site located in Mt. Jumbong, Korea. CWD mass (Mg/ha), input rate of CWD mass (Mg $ha^{-1};y^{-1}$), and decay rate constant (1/y) were 20.6, 1.20, and 0.058 for Q. mongolica forest, 12.2, 0.44, 0.106 for A. holophylla forest, and 5.0, 0.00, and 0.086 for P. densiflora forest, respectively. CWD mass was classified into species, types (log, snag, and stump), and decay classes (I-V). The proportion of logs was higher than that of the other CWD types in Q. mongolica forest because of wind-related mortality, whereas the proportion of logs was similar to the proportion of snags in A. holophylla forest and P. densiflora forest. CWD mass, input rate, decay rate, and distribution reflected the status of forest regeneration and succession for three forests. Mass dynamics were affected interactively by a variety of factors including species, microclimate, and topography, but these effects were hardly distinguishable in this study because of the limited number of comparable sites and pieces of CWD. Thus, further studies will require data regarding long-term microclimate and CWD mass dynamics in a variety of forest types, which could represent diverse environmental factors.