Air Pollution by Vehicle Emissions in the Suburban Area of the Sochi Black Sea Region

The assessment was carried out in beech stands on belt test plots of 25 × 200 m (0.5 ha each) along roads with different traffic intensity, at a distance of 0-30 m from the road, in the basins of the Shakhe, Khosta, Bolshaya Kherota, and Psakho rivers. The state of the atmospheric air in the tree trunk zone was assessed based on the species composition of epiphytic lichens, the thickness of the forest litter, the taxation characteristics of the tree stand, and allelopathic activity at an analytical concentration of 1:50. Based on the analysis results, zones of low pollution (with a field tolerance index of 2.8-5.0), moderate pollution (4.8-6.0), and high pollution (6.5-7.8) were identified. The overall vital condition of the forest stand varies from 0.62 to 0.53 %: the share of healthy forest stand is recorded from 0.0 to 23.1 %, the share of weakened stands varies in the range of 37.2-44.3, heavily damaged - 33.3-47.1 %. A decrease in the forest litter thickness (4.5-6.9 cm) with an increase in allelopathic activity and an increase in the field tolerance index was noted. It was determined that there is a predominantly negative statistically significant relationship between the values of atmospheric air quality and the vital condition of the forest stand (r = -0.946…-0.927). A positive relationship was noted only for heavily damaged forest stands in the range of the field tolerance index up to 5.0 and for destroyed (dying) forest stands along the entire gradient of anthropogenic pollution - 2.8-7.8.