Home – Home – Jornals – Contemporary Problems of Ecology 2021 number 2

The decomposition process in larch forests, which occupy a significant area of the boreal zone and are most often subjected to strong ground fires, remains poorly understood. In a long field experiment (850 days), we observed the decomposition of the dominant types of litter (needles, leaves, branches, grass) in natural and disturbed larch forests of the Russian Far East. We measured mass loss, the dynamics of carbon (C) and nitrogen (N), respiration, and environmental conditions (temperature and humidity). It was found that 15 years after a long-lasting surface fire, the supply of C and N with land litter decreased by 2,2 times compared to the pre-fire level. At this stage of post-pyrogenic succession, a decrease in the proportion of woody and an increase in the proportion of low lignin grass litter was observed. We did not find differences between the studied stands in the rate of mass loss for leaves, grass, and branches, while the needles in the post-pyrogenic larch decomposed more slowly than in the control in the later stages of the experiment (850 days: p = 0,0035). A lower intensity of respiration of decay needles on burns compared with the control ( p = 0,0207) and a decrease in the N content of decaying needles in the later stages of the experiment ( p = 0,0234) indicate inhibition of microbiological activity. A decrease in the total supply of N with litter in the post-pyrogenic stand, combined with a low decomposition rate of needles, restrains the release of N and its availability to plants and microorganisms, which may affect the restoration of the boreal larch ecosystem damaged by fire.