Human-caused anthropogenic greenhouse emissions impact the climate globally. In this pilot study, we aim to reveal the influence of hydrocarbon emissions on pine forests by applying a stable carbon isotope analysis in pine tree rings (δ¹³C_ptrw). Our study was conducted in an industrial giant oil field reservoir (UVRT) and natural reserve (Raifa) sites, the Tatarstan Republic, Russia. Our results show a decreasing δ¹³C_ptrw at the UVRT site in 1943, when oil extraction started, and in 1970, when it reached maximum production. We found that the δ¹³C_ptrw from UVRT indicates developing unfavourable drier conditions and a suppressed tree growth caused by both human-induced oil and deposit infrastructures and natural processes compared to the undisturbed Raifa site. A 5-year running correlation analysis showed a significant difference between the sites in 1965 over the period of 1930 to 2021. The δ¹³C_ptrw values from Raifa are more negative compared to UVRT, which can be explained by a higher forest sensitivity to human-induced impacts. From an eco-physiological point of view, the decreasing of intercellular (c_i)-to-ambient (c_a) CO₂ concentration ratios at the leaf level and the increasing of intrinsic water-use efficiency (iWUE) along with a decreasing of tree-ring widths at the UVRT site (1970–2021) indicate the development of drought conditions.