Особенности начального разложения хвои в сосняке брусничном в среднетаежной подзоне Карелии
Keywords: mass loss; ground vegetation microgroups; hydrothermal conditions
Plant litter decomposes via several stages, the most intensive one being the early stage, when it is mostly readily extractable compounds that are released, contributing to annual nutrient cycling. The aim of this study was to find patterns in the rate of initial decomposition of needle litter depending on the ambient hydrothermal conditions in a cowberry pine stand both in general and in different ground vegetation microgroups. The measured parameters were air temperature and relative humidity, temperature of the forest floor and underlying soil horizons, amount and pH of precipitation and percolating water. The effect of mean monthly values of these parameters on the rate of needle litter decomposition in specific months during the first growing season was estimated both for the entire stand and under different ground vegetation microgroups. Studies have shown that the rate of needle decay is influenced the most significantly by hydrothermal parameters associated with forest floor temperature and moisture. The effect of the communitymicrogroup structure becomes visible only late in the growing season in the lichen-dominated ground vegetation microgroup, probably owing to the seasonal excess of moisture in its forest floor. Differences in needle decomposition rates between ground vegetation microgroups vanish during the winter season under the effect of abiotic factors. The degree of needle fall decay in the cowberry pine stand in the middle taiga subzone was 31.36 ± 3.32 % after the first growing season (110 days), and 42.16 ± 0.02 % over most of the annual cycle (335 days).
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