NWO - VENI: The fungal factor in variation of wood decay rates: from local to global carbon cycling

Knowledge on the decay rate of woody resources is essential for calculating the ability of forests to sequester carbon and, consequently, for assessing the impact of forests on local and global C cycling. However, local variation in wood decay rates is not well predicted by the commonly used models which are mainly driven by wood characteristics and abiotic conditions. The proposed research will indicate the importance of community dynamics of wood-rot fungi to spatial and temporal variation in wood decay rates in temperate forests. The type of rot has an impact on wood structure and decay rates. In addition, colonization and growth of rot fungi can be suppressed by the presence of initial wood-colonizers (bacteria and micro-fungi) or by the presence of other rot fungi. Therefore, I hypothesize that a substantial fraction of the variance in wood decay rates can be ascribed to 1) the frequency of occurrence of different rot types 2) antagonism expressed by initial wood-colonizers, and 3) antagonistic interactions between different rot fungi. To test these hypotheses, I will determine wood decay parameters and identify dominant decomposers in samples of tree stumps of different age classes of a deciduous tree species and in woody material of different sizes from a ?common garden? experiment. The data will be used to build a new wood decay model which explicitly incorporates the frequency of occurrence of different rot-types and the decay rates associated with those rot types. Observed variation in wood decay rates of both our study and that of others will be used to validate and fine-tune the new model. This study will not only have impact on the estimations of C budgets of forests but will also yield new insights in the functioning of wood-inhabiting microbial communities.