Faster than expected: release of nitrogen and phosphorus from decomposing woody litter

Deadwood represents globally important carbon (C), nitrogen (N), and phosphorus (P) pools. Current wood nutrient dynamics models are extensions of those developed for leaf litter decomposition. However, tissue structure and dominant decomposers differ between leaf and woody litter, and recent evidence suggests that decomposer stoichiometry, in combination with litter quality, may affect nutrient release. We quantified decomposition and release of C and nutrients from woody litter for two stem sizes of 22 tree species in a P-limited temperate forest near Sydney, Australia, and compared these to estimates from leaf litter literature. Following theory, N and P accumulated during early decomposition, but began to decline earlier than expected based on work in leaves. Woody litter converged on higher C : N (50) and N : P (80) ratios than in leaf litter studies. C : N at which N was released was higher in larger stems (c. 124) than in smaller stems (c. 82), both being higher than in leaf litter. Drawing from the literature, these differences in N and P dynamics may be due to the identity of wood decomposers. C : N of wood decomposers is higher than the mean C : N of leaf litter decomposers, and this difference in stoichiometry may have important flow-on effects for nutrient cycles in forests.