The temporal and spatial variations of stoichiometry and carbon (C) storage of the dead branches were revealed in the natural forest trees after having investigated their biomass. The results indicated that:(1) the biomass of the dead branches from a single tree, increased with the forest age and the average annual cumulative biomass of the dead branches, was 0.22 kg per tree; The biomass of the dead branches increased with the enhancing diameters, and the larger diameter grades would induce the easier dead branches. Biomass of the dead branches originally increased and then decreased with increasing forest age, and the highest biomass value was 10.93 t/hm² contributing 17.79% of the total ground living biomass in the mature forests; (2) the C, N, P, K contents of the dead branches were 491.01, 4.13, 2.75 g/kg and 1.83 g/kg, respectively, and were higher than those on the living branches, whereas the K content showed the opposite trend. The ratios of C:N, C:P, and N:P in dead branches of different forests were 128.58, 232.79, and 1.95, respectively, and were higher than those in the living branches. Forest age had little effect on element contents and stoichiometry, which could indicate that element content of dead branches of the standing trees varied slightly; and (3) the C density of the dead branches first increased and then decreased with forest age, and was highest in the mature forests. The average carbon density of different aged forests was 2.63 t/hm², which was 20.74% of that of the living forests. It was considered the variation law that the biomass and carbon density of the dead branches increased with forest age, resulting in a potentially huge carbon sink. This is a fundamental factor to consider for environmental and forestry management.