Sulfur content in needles of cedar (Pinus sibirica Du Tour) and siberian fir (Abies sibirica Ledeb.) of the Southern Baikal Region: Influence of industrial emissions

The paper presents the results of studying the sulfur content in the needles of cedar and Siberian fir of the Southern Baikal Region, carried out in the 2014–2015 period. The research aims to determine whether Baikal Pulp and Paper Mill (BPPM) are the primary stress factor of abiotic nature, which leads to the degradation of cedar and Siberian fir stands in the Southern Baikal Region. The authors have determined that the primary factor is the long-term impact of the emission of pollutants from heat power companies in the Irkutsk Region, as indicated by numerous studies using mathematical modeling methods. The research demonstrates that the assimilation organs of the cedar are more sensitive to the effects of sulfur dioxide compared to the needles of Siberian fir. Therefore, cedar needles can be considered as a more sensitive indicator of atmospheric pollution with sulfur dioxide. The authors have established that the primary source of contamination of Siberian fir needles is the SO₂ emission from the heat and power enterprises of the Irkutsk Region and not the emission of sulfur-containing compounds of the BPPM. The authors found that in the period from 2010 to 2019, the total SO₂ emissions from large industrial companies were an order of magnitude lower than the volumes of SO₂ emissions from heat power companies in the Irkutsk Region. These emissions will provoke a further deterioration in the state of the boreal forests of the Southern Baikal Region.3