Abstract

Boreal forests are sensitive to external factors, and even small variations can completely alter their natural carbon (C) balance. Today, we face not only the consequences of climate change but also intensified human activity. In most cases, forest disturbances decrease ecosystem stability by disrupting key structural components, often transforming ecosystems into C sources. Soil CO2 efflux is a critical indicator of recovery following disturbances. This study explored the impact of different disturbance types (clear-cutting alone, wildfire alone, and both) on soil CO2 efflux for various ground-cover vegetation (lichens, green mosses, and Sphagnum mosses) in Scots pine forests of the Siberian central taiga. The data indicate that changes in soil CO2 efflux are predominantly driven by wildfires in lichen-dominated plots, by clear-cutting in green moss-dominated plots, and by both wildfires and clear-cutting in Sphagnum moss-dominated plots. Soil CO2 efflux was reduced by 75 and 40% in lichen- and Sphagnum moss-dominated plots, respectively, across burned sites compared to the undisturbed site. The impact of clear-cutting is observed in a decline of the emission rates of from 40 to 60% compared to the undisturbed site for lichen- and moss-dominated plots. The interactive effect of wildfire and logging is established in the reduction of the emission rates, and this decline depends on the type of ground cover. This finding highlights the substantial impact of wildfires and clear-cutting on the C dynamics of Siberian boreal ecosystems. The diurnal and seasonal variations in soil CO2 efflux were most pronounced for moss-dominated plots at disturbed sites. The main factors determining emission efflux variations are carbon content, type of ground cover, and forest floor thickness. This study contributes to a better quantitative understanding of soil CO2 efflux in boreal Scots pine forests from the differently disturbed areas.

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