| Abstrakt: |
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. Plain Language Summary: Living trees are an essential reservoir for carbon storage. While the process of photosynthesis describes the ability of plants to fix atmospheric carbon, the decomposition of deadwood is the first stage of recycling this nutrient. Aerobic decomposition of deadwood is mainly carried out by specialized fungi that release carbon into the atmosphere during their respiration processes. Most microorganisms require oxygen to utilize deadwood and form carbon dioxide during respiration. In addition, archaea can respire carbon dioxide in the absence of oxygen, which leads to methane production. In our study, we determined the gas emission rates of carbon dioxide and methane for 13 tree species and investigated the influence of regional climate and habitat conditions and types (grassland and forest). The emission rates of carbon dioxide and methane largely differed among tree species, which probably depended on their wood traits. Both gas emission rates were higher under humidity, while higher temperatures increased only carbon dioxide emission rates. Methane emission rates were independent of habitat conditions, while carbon dioxide in forest habitats were higher and influenced by naturally existing tree species. Our results improve future assessment of the impact of deadwood on the global carbon cycle. Key Points: Tree species identity is an important driver of CO2 and CH4 emission ratesCO2 emission is two‐thirds higher in forest compared to grassland habitatsForest management intensity decreased CO2 emission rates, whereas CH4 was only affected by single management components [ABSTRACT FROM AUTHOR] |
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