Although coarse woody debris (CWD) represents one of the major carbon pools in natural forest ecosystems, little information is available about its CWD carbon stocks. This study demonstrates the importance of proper estimation of carbon stocks in CWD, which accounts for the decay process of CWD, on an example of a natural mountainous spruce forest located in Central Europe. The study accounts for aboveground coarse woody debris including standing dead trees, lying deadwood, and naturally formed stumps. Basic mensurational information (diameter, height, decay class) about dead wood was collected in the field during the inventory of the forests of the nature reserve Babia hora. The data were used for the calculation of CWD timber volume. In the next step, CWD timber volume was converted to carbon stock using the carbon proportion of 50.1% and density values of decay classes derived from the information published elsewhere. The analysis revealed that when CWD timber volume was converted to carbon stocks using the basic wood density of fresh wood, C stocks were overestimated by 40% or more depending on the developmental stage and elevation. The results also revealed that as the elevation increases, CWD carbon stocks decrease and the differences between the developmental stages diminish.