engleski

Density and carbon concentration of downed dead wood by decay classes for ten tree species in Croatia

Dead wood (DW) is an important component of forest ecosystem and in the context of climate change and carbon (C) accounting policy under UNFCCC and EU regulations it is recognized as a long-term C pool. The aim of our study was to provide national DW volume conversion factors, i.e. dead wood densities (DWD) and C concentrations (CC) by decay classes, which could be used for accounting of C stocks and C stock changes in DW pool in the National GHG Inventory Report (NIR). We hypothesized that investigated traits for specific tree species group (ring-porous, diffuse-porous, non-porous) will differ with respect to different biogeographical region (BGR). Research was conducted on ten tree species from three BGRs, Continental, Alpine and Mediterranean. Stem discs were sampled from downed DW and categorized into five decay classes, from 0 (raw wood) to 4 (very decayed DW). In total, we collected 446 DW samples evenly distributed between tree species and decay classes. Samples were analysed for DW density (DWD) and C concentrations (CC). DWDs showed decreasing trend with respect to decay class, while for CC no trend regarding decay classes was observed. For each tree species group, DWDs by decay classes were compared between different BGR. In ring-porous group, a significant difference was observed in DWD between samples collected in Mediterranean and Continental BGR for decay classes 0-2, while in non-porous group DWDs significantly differ between samples collected in Alpine and Mediterranean BGR for decay classes 2-4. By using obtained volume conversion factors from this study, we provided new estimate of downed DW C stocks in Croatia. Also, we performed a comprehensive literature search on DWDs by decay classes for genera investigated in our study and observed differences in DWDs reduction patterns.

coarse woody debris, decomposition, density reduction pattern, volume conversion factors

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