Chemical composition of volatile and extractive compounds of pine and spruce leaf litter in the initial stages of decomposition

Abstract. A litter bag experiment was conducted to analyze changes in chemical composition in Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) needle litter in the first stages of decomposition in natural conditions. The emission rates of monoterpenes and concentration of extractive secondary metabolites were determined five times over a 16-month period. It has been shown that pine and spruce needle litter in the first stages of decomposition (up to 165 days) emits monoterpene hydrocarbons into the gas phase with the rates comparable to those in emissions from live needles of these trees. This suggests that leaf litter is an important source of atmospheric terpenes. It has also been proved that the litter contains considerable amounts of non-volatile substances that can be precursors of oxidized volatile compounds formed as a result of enzymatic reactions. Non-volatile but water soluble secondary metabolites of the leaf litter may be involved in nutrient cycling and have an influence on soil community.