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Context: We investigated the relationships between decay classes, morphological characteristics and chemical compounds in Abies alba Mill. and Fagus sylvatica L. stumps in two forest stands in the central Apennines (Italy). The analysis of deadwood decomposition is important in estimating carbon sequestration potential and carbon residence time in forest ecosystems. In addition, deadwood decomposition affects nutrient cycling and microhabitat distribution. Aims: The overall aim of this study was to investigate the decomposition processes in a mountainous Mediterranean ecosystem, and specifically to assess changes in chemical variables (lignin, cellulose, carbon and nitrogen content) in deadwood during the decomposition process, in relation to decay classes and to the species. Methods: Cross-sections were collected from stumps. Samples were assigned to visually discernible decay classes, and cellulose, lignin and carbon (C) and nitrogen (N) content in relation to total dry mass were analysed during the decay process. Results: Results showed how C/N ratio decreased over decades due to an increase in nitrogen content. On the contrary, carbon concentration in stumps remained substantially stable. Lignin degraded slowly in comparison with cellulose and differences between species were observed. Conclusion: The hypothesis that the conifer species would decompose faster than deciduous species did not prove correct. The slower decay of lignin compared to cellulose suggested that lignin could be an important long-term source of soil organic carbon, and that this process could be greatly affected by forest species mixtures. Finally, decomposition processes in the investigated montane-Mediterranean forests were definitely faster than in the colder climates of northern Europe. [ABSTRACT FROM AUTHOR]

In this study, silver fir – European beech forest types were examined in their structure and tree species composition. Two study areas, one in the Molise Region in Italy (Abeti Soprani) and one in the Dinaric Mountains in Slovenia (Leskova dolina), were compared in their dynamics and present structure. The aim of the study was to assess if a standardized field survey protocol can supply indicators related to forest structure and composition, and deadwood amount in two different Natura 2000 sites. The present structure and composition were evaluated on a 1-ha plot in each area. All live trees, standing and downed dead trees, snags, stumps, and lying coarse woody debris were censed. For each individual tree, the position within the plot, the species, diameter at breast height, height or length, crown structure and height, and decay level (only for deadwood) were recorded. The forest structure was influenced by past management, modifying the tree density, the amount of deadwood and the growth trends. The spatial distribution of trees and their vertical stratification show pluristratified stands with a mainly horizontal random pattern. The assessment of forest parameters in large plots could be an opportunity to evaluate the best choices for a nature-based silvicultural approach. [ABSTRACT FROM PUBLISHER]