Abstract—

This paper examines fire-induced transformations of the main ecosystem components in steppificated pine forests that grow in the mid-mountain part of the Selenga River basin (Western Transbaikalia). It has been established that medium-intensity ground fires that occur most frequently in the region transform the living ground cover and alter the composition and properties of forest litter, as well as the morphological, physicochemical, and hydrothermic properties of soils. The changes in the species diversity, projective cover, and phytomass of the herbaceous vegetation observed in the course of the postfire dynamics are minor. In contrast, the parameters of the moss–lichen cover, forest litter, and soils undergo significant transformations. In recently burned areas, mosses and lichens are completely destroyed; while the forest litter is thin, consists primarily of recently fallen needles and branches, and its reserves are low. Immediately after a fire, the moisture content in the upper pyrogenic soil horizons decreases, while the soil temperature increases. The following pyrogenic signs are observed in the humus-accumulative horizons of the soil profile: very dark coloration of organic matter combustion products, alkalization, and increased concentrations of calcium and carbon cations; concurrently, an increase in content of oxalate-soluble iron is observed in the illuvial horizons. At 5 or more years after a ground fire, a number of positive changes are observed, including an increase in forest litter thickness, formation of the moss–lichen cover, gradual changes in the chemical properties, a decrease in soil temperature, and some stabilization of field moisture parameters in the upper part of the soil profile. It has been established that the pyrogenic transformations of the forest litter, moss–lichen cover, and soils adversely affect the postfire restoration of the forest vegetation and regeneration of pine stands in areas affected by medium-intensity ground fires.

中文翻译：

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色楞格河流域（西外贝加尔）山中部分松林的火灾后变化

摘要-

本文研究了火引起的主要生态系统组成部分在色楞格河流域（西部外贝加尔湖）中山区生长的阶梯状松林中的变化。已经确定，该地区最常发生的中等强度地面火灾会改变有生命的地面覆盖物，改变森林凋落物的组成和特性，以及土壤的形态、物理化学和水热特性。在火灾后动态过程中观察到的草本植被的物种多样性、投射覆盖和植物群的变化很小。相比之下，苔藓地衣覆盖、森林凋落物和土壤的参数发生了显着变化。在最近被烧毁的地区，苔藓和地衣被完全摧毁；当森林枯枝落叶稀薄时，主要由最近掉落的针叶和树枝组成，其储量较低。火灾发生后，上部热解土壤层的含水量立即下降，而土壤温度升高。在土壤剖面的腐殖质积累层中观察到以下热解迹象：有机物质燃烧产物的颜色非常深，碱化，钙和碳阳离子浓度增加；同时，在沉积层中观察到可溶于草酸盐的铁含量增加。在地面火灾发生 5 年或更长时间后，观察到许多积极变化，包括森林枯枝落叶厚度增加、苔藓地衣覆盖形成、化学性质逐渐变化、土壤温度降低、以及土壤剖面上部的田间水分参数的一些稳定性。已经确定，森林凋落物、苔藓-地衣覆盖物和土壤的热解转化对受中等强度地面火灾影响的地区的森林植被的火灾后恢复和松树的更新产生不利影响。