Abstract

Decomposition processes in larch forests, which occupy a significant part of the boreal zone and are most frequently affected by devastating ground fires, are poorly researched. In the course of a long-term (850 days) field experiment, the decomposition of litter types typical for boreal larch forests of the Russian Far East (needles, leaves, branches, and grass) was monitored in larch stands, both natural ones and those disturbed by fire. The following litter parameters were measured: mass loss, carbon (C) and nitrogen (N) dynamics, respiration, and environmental conditions (temperature and humidity). It is established that, 15 years after a long-lasting ground fire, the inflow of C and N with ground litter has decreased 2.2 times in comparison with the prefire level. At this stage of post-fire succession, the share of tree litter is lower, while the share of low-lignin grass litter is higher in comparison with the control. No differences in mass loss rates were identified between the studied stands for leaves, grass, and branches. However, at the end of the experiment (day 850, p = 0.0035), needles were decomposing more slowly in the burned larch forest than in the control. A lower CO₂ emission intensity featured by the needle litter in the postfire forest (p = 0.0207) in comparison with the control and a lower nitrogen content in decomposing needles at later stages of the experiment (p = 0.0234) indicate that the post-fire factor inhibits microbiological activities. A decrease in the total N inflow with litter in the post-fire stand, combined with a lower needle decomposition rate, results in a slower release of nitrogen and its availability to plants and microorganisms, which may affect the restoration of boreal larch forest ecosystems damaged by fires.

中文翻译：

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俄罗斯远东森林火灾后落叶松林中主要凋落物类型的分解和氮释放

摘要

落叶松森林的分解过程研究不足，该分解过程占据了寒带的很大一部分，并且最容易受到毁灭性大火的影响。在长期（850天）的野外试验过程中，在落叶松林中监测了俄罗斯远东北方落叶松林典型的凋落物类型（针，叶，树枝和草）的分解情况。那些被火困扰的人。测量了以下垫料参数：质量损失，碳（C）和氮（N）动态，呼吸作用和环境条件（温度和湿度）。可以确定的是，在长期持续的地面火灾之后的15年里，地面垃圾中的C和N的流入量比火灾前的水平下降了2.2倍。在火灾后的过渡阶段，树木凋落物的比例较低，与对照相比，低木质素草凋落物的比例更高。在所研究的叶子，草和树枝的立场之间，没有发现质量损失率的差异。但是，在实验结束时（第850天，p = 0.0035），在燃烧的落叶松林中，针的分解速度比对照中的慢。与对照相比，后燃森林中针叶凋落物的特征在于较低的CO ₂排放强度（p = 0.0207），而在实验的后期阶段分解针叶中的氮含量较低（p = 0.0234），表明后火因子抑制微生物活动。火后林分中凋落物的总氮流入量减少，针分解率降低，导致氮释放速度减慢，氮素对植物和微生物的利用率降低，这可能会影响受损的北方落叶松森林生态系统的恢复。被大火烧毁。