Mountainous sites can only grow a limited variety of vegetation types due to their fragile soil conditions. In the north of Iran, mountainous sites are commonly occupied by Crataegus and Berberis shrubs, which are natively distributed in Asia, Europe, North America and Africa. Despite the widespread distribution of these two species, the effect of pure and mixed canopy composition of these species on soil fertility and microbial activities (as soil function indicators) has not been considered. In this paper, five types of canopy composition have been studied for their effect on soil function; including pure Crataegus (PC), and pure Berberis (PB), as well as mixed Crataegus and Berberis with almost equal canopy cover (50C:50B), Crataegus-dominated stand (70C:30B), and Berberis-dominated stand (30C:70B). A total of 225 soil samples (5 plant types × 15 samples × 3 soil depths including 0–10 cm, 10–20 cm and 20–30 cm belowground) were taken from the field, transferred to the laboratory and analyzed. PCA results showed a difference in the soil characteristics between the canopy composition types, with the first and second axes justifying 46.67% and 14.12% of the total variance, respectively. The 50C:50B mixed canopy composition resulted in soils with higher values of soil organic matter fractions (i.e. particulate and dissolved C and N), C and nutrient (N, P, K, Ca and Mg) pools, and soil microbial (i.e. respiration and biomass) and enzyme (urease, acid phosphatase, arylsulfatase and invertase) activities, especially in the topsoil (0–10 cm). Soil function indicators decreased in ranked order of 70C:30B > 30C:70B > PC > PB plant types. As a conclusion, it can be stated that the equal ratio of Crataegus and Berberis can enhance soil function and create fertile islands in the high altitudes of natural ecosystems.

由于土壤条件脆弱，山区只能种植有限种类的植被。在伊朗北部，山区通常被山楂和小檗灌木占据，它们原生地分布在亚洲、欧洲、北美洲和非洲。尽管这两个物种分布广泛，但尚未考虑这些物种的纯和混合冠层组成对土壤肥力和微生物活动（作为土壤功能指标）的影响。本文研究了五种类型的冠层成分对土壤功能的影响；包括纯山楂（PC）和纯小檗（PB），以及混合山楂和小檗具有几乎相等的树冠盖 (50C:50B)、山楂属植物 (70C:30B) 和小檗- 占主导地位的立场 (30C:70B)。从田间共采集225个土壤样品（5种植物×15个样品×3个土壤深度，包括地下0-10厘米、10-20厘米和20-30厘米），转移到实验室进行分析。PCA 结果显示冠层组成类型之间的土壤特征存在差异，第一轴和第二轴分别占总方差的 46.67% 和 14.12%。50C:50B 混合冠层组成导致土壤有机质分数（即颗粒和溶解 C 和 N）、C 和养分（N、P、K、Ca 和 Mg）池以及土壤微生物（即呼吸和生物量）和酶（脲酶、酸性磷酸酶、芳基硫酸酯酶和转化酶）活性，尤其是在表土（0-10 cm）中。土壤功能指标下降70C:30B > 30C:70B > PC > PB 植物类型。作为结论，可以说等比山楂和小檗可以增强土壤功能，在自然生态系统的高海拔地区创造肥沃的岛屿。