Dynamics and composition of litterfall in an unmanaged Norway spruce (Picea abies) forest after bark-beetle outbreak

We investigated litterfall chemistry and fluxes, and cellulose decomposition in litter floor in mature, unmanaged Norway spruce stands in the catchments of Plešné and Čertovo lakes (Czech Republic) during 2003–2013. The Plešné forest was infested by the bark beetle (Ips typographus) in 2004, and 88–99% of trees had died by 2011. Total litterfall and its composition were similar in both catchments in 2003. The litterfall increased from 5.4 to 42 t/ha/yr after the infestation and remained relatively high (5.0 t/ha/yr) until the end of the study even though > 52% of trees were already broken. The chemical composition of most spruce litter categories changed after infestation, with the most pronounced trends in C (decrease) and Ca (increase) concentrations. Moreover, Mg, K, and P concentrations increased in the total Plešné litter due to an increasing proportion of rowan litter. Cellulose decomposition increased in the litter floor after infestation.