Direct and Indirect Assessment of Carbon Stock in Deadwood: Comparison in Calabrian Pine (Pinus brutia Ten. subsp. brutia) Forests in Italy

Deadwood is a key element in forest ecosystems contributing to biodiversity conservation, carbon (C) stocking and cycling, and nutrient inputs to soil. Forest management has an important role to maintain deadwood temporary C stock by regulating the amount of deadwood in forests during harvesting operations. Deadwood C stocks can be estimated directly, by measuring C concentration in deadwood samples, or indirectly, by converting the biomass into the amount of C stored in the deadwood. The aim of the study was (1) to compare direct and indirect methods for deadwood C stocks estimation; (2) to determine differences between the two methods; and (3) to evaluate the most appropriate, easiest, and least expensive method depending on specific circumstances. The investigation was implemented in a Calabrian pine (Pinus brutia Ten. subsp. brutia) forest located in Central Italy. In 18 sample plots, deadwood biomass was measured separately by component (logs, snags, stumps) and decay class. During a field survey, 150 deadwood samples were collected and analyzed in the laboratory for moisture content, mass determination, and direct and indirect estimation of C content. The results showed small differences in the estimation of deadwood ( stock using direct and indirect methods. We propose that indirect estimation of C stock, which is less demanding of time and monetary resources, can replace direct estimation, and using the same coefficient for different deadwood components and decay classes produces reliable estimates.