Deadwood is an important component of the global carbon cycle, and its decomposition releases carbon dioxide (CO₂) and methane (CH₄) into the atmosphere. However, the main drivers of these greenhouse gas emissions from deadwood are not well understood. We investigated drivers that govern the CO₂ and CH₄ emission rates of 793 deadwood specimens from 13 different tree species, which were exposed on 27 forest and 38 grassland plots at Schorfheide-Chorin (Germany) for one year. Tree species identity was an important driver for emissions of both gases, whereas habitat type and management intensity were only important for CO₂ emission rate. CO₂ emission rates were positively linked to mass loss and were one-third higher in forest compared to grassland habitats. The wood traits organic extractives, lignin, and sulfur content were negatively associated with CO₂ emission rates, whereas carbon, nitrogen, and magnesium content showed the opposite effect. Among climate variables, air humidity in forest and soil moisture in grassland habitats positively affected CO₂ emission rates. CH₄ emission rates showed a negative relationship with increasing wood density exposed in both habitat types but were positively related to tree species with higher sulfur contents. Taken together, CO₂ emission rates from deadwood were well predicted by wood traits, management intensity and climatic variables, whereas CH₄ emission rates were less well predictable and were influenced only by wood traits that differed from those of CO₂ emissions. Our results provide a deeper insight into the mineralization processes of deadwood and should be considered in further carbon cycle assessments.