Structure of forest litter in larch forests of Middle and Southern Siberia

Abstract Forest litter plays a significant role in the functioning of forest ecosystems. As a product of forest and soil interaction, forest litter participates actively in the processes of soil formation and plant nutrition. We measured the total stock and analyzed difference in structure of forest litter formed in permafrost larch forests growing in the different climatic zones: in northern taiga of Central Siberia and in the mountain taiga of the Eastern Baikal region. The forest-forming species in both regions is Gmelin larch (Larix gmelinii (Rupr.) Rupr.), but climatic conditions and soil cover in these regions differ. It was found that average stock of forest litter is higher in mountain larch forests of the Eastern Baikal region in comparison with northern boreal forests. The litter composition in these larch forests is characterized by a relatively larger contribution of soft fractions (needles and leaves) in contrast to the larch forests in the northern taiga, where a higher contribution of hardly decomposable components (branches, cones, bark, semi-decomposed wood, thick roots, and moss residues) was observed. Higher stock of fermented plant residues in comparison with humified ones indicated the accumulation of incompletely decomposed plant residues on the soil surface of these northern forests.