Assessment of the impact of associated gas flaring on the radial growth of Pinus sylvestris (Ozernoe oil field, Perm region, Russia)

The paper discusses the question of influence of associated gas flaring on radial growth of Pinus sylvestris. The studied area is Ozernoye oil field of Krasnovishersky district of Perm region (Russia). The main research method is dendrochronological analysis. The wood cores of Pinus sylvestris were selected in the summer of 2020 using a Pressler increment borer according to the standard methodology. Cores were taken from two plots. The main plot is 100 m from the associated gas flaring torch and background plot is 11 km from the torch. The calculation and measurement of the width of the radial growth of wood were made on the machine for measuring tree rings LINTAB 6. Numerical parameters of wood growth obtained for both plots. The average value growth of wood at the main plot is 1.426 mm/year; at the background plot 1.808 mm/year. The relative decrease of average growth of wood over 20 years before and after the start of associated gas flaring at the main plot 1.45 times higher than at the background plot. The radial growth decreases systematically at both plots for 20 years since the beginning of associated gas flaring. But the rates of decrease are 1.52 1.67 times higher near the torch. The trend for recovery, as well as increase in the growth values, 10 20 years after the start of associated gas flaring, was not revealed. Therefore, the explicit negative impact of associated gas combustion on the radial growth of wood in nearest forest were noted. Maximum growth rates at the main plot were noted for trees ages 0 55 years. It is not supporting the conclusions of some researches [7,37] that Pinus sylvestris has the most intense growth during 30 35 years old. Revealed [37] high levels of chemical and dust atmospheric contamination, reducing growth of wood, most likely cannot be achieved by the associated gas flaring by the single torch. Positive (fertilizing) influence of Ca, K, Na, Mg, Mn [29,30] compounds emissions is not marked as well. We guess that thermal is the main negative factor for the plot near associated gas flaring. Our research could be continued to the studying of the influence of spatial, climatic aspects, volume and intensity of gas flaring process on the state of forest stand.