We used compatible tree biomass equations for each component grouped by species and decay classes, and carbon fractions of above-ground and below-ground parts, based on the 8^th Chinese National Forest Inventory (CNFI) data in Guangdong Province and the deadwood investigation data from typical sampling in 2016, to estimate the dynamics of the forest deadwood carbon pool in Guangdong Province, including the effects of deadwood type, stand type, and age groups. Furthermore, the contribution of stand growth characteristics and natural disasters to the deadwood carbon pool were quantified. The results showed that the carbon storage of the deadwood pool of arbor forests in Guangdong Province increased 5811.86 Pg from 2007 to 2012, which accounted for 2.94% of biomass carbon in arbor forests during the same period. Logs contributed more carbon to deadwood pool than snags. Broad-leaved mixed forests and Pinus massoniana contributed approximately 70% to the deadwood carbon pool. Within the same forest type, the deadwood carbon storage of Pinus massoniana, light hardwoods, Pinus elliottii, broad-leaved mixed forests, and hardwoods accounted for a larger proportion (>4%) of standing carbon stock, whereas Eucalyptus and Cunninghamia lanceolata accounted for a lower proportion (<1%). With respect to age groups, middle-aged stands accounted for the largest proportion of the increased carbon, whereas over-mature stands accounted for the smallest. Comparing the existing biomass carbon storage within the same age group revealed an upward trend from 2.03% for the young-aged to 4.56% for the over-mature stands. The increased carbon density was (0.7612 ±3.3988) Mg/hm² in the province. Death owing to competition or old age was very common in the stand, and was observed in approximately 60% of the stands with deadwoods, but contributed to less than 1/4 of the increased deadwood carbon. Rather, natural disasters, which only happened in approximately 10% of the stand, contributed more than 40% to the increased deadwood carbon. The increased deadwood carbon from 2007 to 2012 declined until 2016 by approximately 85% to 785.57 Pg. The degree of decay of logs was greater than for snags. The degree of decay varied among different species and was lowest for Cunninghamia lanceolata. Human disturbance, such as over-cleaning, and decay of trees could be the main reasons for the reduced carbon storage.