Along the chronosequence, the clay particle formation rate decreased logarithmically from >90 g m⁻² a⁻¹ at the youngest to <0.2 g m⁻² a⁻¹ at the oldest sites. Stocks of silt+clay-sized particles varied from 9.6 to 1724 kg m⁻² across all soil profiles studied. increasing solum thickness with soil age and increasing proportions of fine fractions, but decreasing specific surface area related with changes in the mineralogical composition of the soils from allophanes to increasingly crystalline Fe oxides. The SOC stocks along the chronosequence were likely influenced by several factors with partly cancelling effects, i.e. Climatic differences induced similar variability in SOC stocks (0.8 to 20.3 kg m⁻²) as did soil age. In the highly weathered soils, the share of subsoil SOC stocks (>20 cm) was 50% or more. The youngest soil of the chronosequence had the lowest SOC stock (7.7 kg m⁻²), and a first maximum of 21.6 kg m⁻² was observed in an allophanic Andosol (at 4.3 ka age), followed by somewhat lower SOC stocks in older soils and a second maximum in the oldest and particularly deeply developed soil (25.6 kg m⁻²). We determined SOC stocks of the entire developed profiles. We used a chronosequence and altitudinal sequence approach to investigate the influence of soil age (1.5 to 1070 ka) and climate (arid to very humid 47–866 m a.s.l.) on the stocks of soil organic carbon (SOC) and stocks of silt- and clay-sized particles. The Galápagos archipelago consists of a chain of volcanic islands of different ages. The significant quantitative differences are seen in the clay stocks. The influence of the shelterbelt on the properties of adjacent arable soils can be traced to a distance of 50-60 m from the shelterbelt edges. The topsoil (0-20 cm) under the shelterbelt significantly differs from the topsoil of the adjacent arable land in a lower bulk density, lower stocks of clay (<0.001 mm) and physical clay (<0.01 mm), and higher stocks of C org. Adjacent arable soils contain less carbonates than soils under the shel-terbelt the removal of carbonates from the layers of 0-200 and 0-300 cm is estimated at 57 and 84 t/ha, respectively. The accumulation of sodium and magnesium in soil water extracts is detected in the deep (200-400 cm) layer of this soil. Data on the contents and stocks of the clay (<0.001 mm) and fine silt (<0.005-0.01 mm) fractions in the soil profile under the shelterbelt attest to the development of its textural differentiation. As a result of tree growth during the past 50 years (age of the shelterbelt), certain changes in the intensity and direction of soil-forming processes have taken place in soils of both the shelterbelt and the adjacent arable land. Background soils are medium-deep light clayey leached chernozems (Luvic Chernozems) on calcareous loesslike heavy loam. The results of a comprehensive study of soils under a 30-m-wide five-row oak shelterbelt of merid-ional orientation and on the adjacent arable fields of the agroforestry landscape in typical forest-steppe of Belgorod oblast are discussed.