Long-term soil temperature dynamics in pyrogenically transformed geosystems of the Tunka depression (Southwestern Cisbaikalia)
N.N. VOROPAI1,2, Zh.V. ATUTOVA2, E.S. SHUKLINA1,3
1Institute of Monitoring of Climatic and Ecological Systems, Siberian Branch, Russian Academy of Sciences, Tomsk, Russia
2V.B. Sochava Institute of Geography, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
3Tomsk State University, Tomsk, Russia
Keywords: burn, natural reforestation, forest fire, microclimate, monitoring, pine forests, soil temperature regime
Abstract
In order to identify the features in the dynamics of the soil temperature regime during the post-fire reforestation of the subtaiga light-coniferous geosystems of the Tunka depression, a study was made of the demutation processes in the pine forests of the Badary urochishche the fires that occurred in 2010. As part of monitoring observations in 2011-2020, the specificity of rehabilitation of understory trees as well as of the shrub layer and live ground cover was determined. The period of appearance of the first shoots of undergrowth was noted; the projective cover of species of all forest-growing layers was estimated. By comparing the dominant composition of secondary succession biocenoses with natural plant communities, indicators of the prospects for successful reforestation were identified. An analysis was made of 10-year-long observation data on the soil temperature regime from the surface to a depth of 3.2 m was carried out at the selected sites. Measurements were made all year round in an automatic mode using atmospheric-soil measuring systems. The differences between the soil temperatures on the disturbed and natural sites, which vary over a year, were revealed. Open soils on the site affected by fire are warmer in the summer and colder in the winter. Snow cover acting as a heat insulator on both sites reduces the differences. However, with late snow onset, the contrasts increase. During the observation period, a decrease in microclimatic differences was observed with the regeneration of vegetation cover, which indicates the reforestation of the temperature regime in the pyrogenically disturbed area. The results obtained at this stage, and also the continuation of the monitoring are applicable to the analysis of pyrogenic transformation of subtaiga light-coniferous geosystems in the south of Eastern Siberia and the forecast of post-fire reforestation of light-coniferous forests of the Tunka depression, taking into account regional specifics. The continuation of comprehensive monitoring will allow for a more detailed assessment of the regeneration of the landscape and climatic conditions of the territory in the future.
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