Deadwood is a substantial reservoir of carbon, and its decomposition plays a crucial role in the global carbon cycle. The fungal community inhabiting deadwood holds a central position in the decomposition process. Variations in the fungal community contribute to differences in the relative decay rates of wood components, such as lignin and holocellulose, thereby influencing the carbon content in decay residues. The classification of wood decay types by fungal decomposers is based on their preference for lignin and holocellulose fractions in wood. Following investigations into deadwood in forests in Japan and Europe, I observed a clear latitudinal gradient in fungal communities within the deadwood of pine and spruce. Additionally, positive relationships were identified between latitude and the frequency of brown rot decay type, where lignin remains with little modification. The wood decay type could impact carbon sequestration in forests, with brown-rotted wood potentially playing a more significant role in soil organic matter accumulation compared to white-rotted wood, where lignin undergoes substantial decay. Climatic variables, such as temperature and precipitation, were found to be significantly associated with both fungal communities and the frequencies of decay types. These results suggest the possibility that global warming may increase the frequency of brown rot decay type, and consequently enhancing carbon sequestratoin in forests to some extent. While global warming may lead to increased carbon emissions from the forest ecosystem as a whole due to accelerated decomposition of soil organic matter, change in wood-inhabiting funcal communities could partially offset these emissions by promoting the dominance of brown rot in wood. An essential consideration concerning wood decay type is that the activities of fungi involved in wood decomposition can have indirect, long-lasting, cascading impacts on forest biodiversity and carbon sequestration by altering the physicochemical properties of deadwood. Therefore, it is crucial to incorporate the effects of deadwood and its decay type into ecological models to predict the long-term dynamics of biodiversity, vegetation, and carbon cycling in forest ecosystems worldwide.