The purpose of our study was to evaluate the spatial arrangement of carbon pools and humic substances maturity in cultivated chernozem soil adjacent to black locust shelterbelt. A plot on arable land adjacent to midfield shelterbelts in southern Poland (Proszowice Plateau) was chosen. Soil samples were taken at different distances from the shelterbelt from a depth of 0-25 cm. Samples were also collected from under the shelterbelt. The pools of organic carbon were highest in samples taken from the farmland closest to the black locust trees. As distance from trees increased, content of humic substances and fulvic acids was found in cultivated soil to be significantly lower. Based on the van Krevelen diagram, it can be concluded that the most mature and the most stabilized humic acids are those in the soil located directly adjacent to the trees.