Carbon emission by soil respiration in a deciduous forest on the southern border of the taiga (Tatarstan, Russia)

Abstract

Soil respiration contributes to the carbon emission losses of terrestrial ecosystems, so its accurate assessment is prerequisite to predict environmental risks resulting from Earth’s climate change. Seasonal dynamics of carbon dioxide fluxes from the soil surface of broad-leaved forest of the Middle Volga region, located on the southern border of the southern taiga subzone, were measured during the growing season. The forest belongs to the polygon Karbon-Povolzhye (Zelenodolsky district, Republic of Tatarstan, Russia). Seven measurements were taken from May to October 2022 in five replicates. The average monthly carbon emission during the growing season and pre-winter period was 0.19±0.01 g C h/m2. The largest emissions were observed at the end of June, the smallest – in September under the decreasing air and soil temperatures. Robust linear regressions were built to predict carbon emission depending on air temperature (n = 35, p < 0.001, r2 = 0.37), temperature of soil at a depth of 1 cm (n = 35, p < 0.001, r2 = 0.30), temperature of soil at a depth of 5 cm (n = 35, p-value < 0.01, r2 = 0.18). The data on carbon flux by soil are presented for the first time for the forest ecosystems of the Middle Volga region. The resulting emission estimates can be used to calculate the total carbon balance for the forest ecosystems of the Middle Volga region.