Forest gaps alter the environmental conditions of forest microclimates and significantly affect the biogeochemical cycle of forest ecosystems. This study examined how forest gaps and non-gap areas affect soil’s physical properties and eco-stoichiometric characteristics. Relevant theories and methods were employed to analyze the impact of forest gaps on nutrient cycling in Pinus densiflora Sieb. (PDS) and Robinia pseudoacacia L. (RPL) forests located in the Taishan Mountains. The results revealed that (1) forest gaps significantly enhanced the soil physical properties of PDS and RPL forests compared to non-gap areas (NPs). Notably, the bulk density of the soil decreased by 53%–12%, particularly in the surface layer (0–20 cm). Additionally, its non-capillary porosity increased by 44%–65%, while the clay and silt content rose by 39%–152% and 24%–130%, respectively. Conversely, the sand content decreased significantly, by 24%–32% (p < 0.05). (2) The contents of C, N, and P in the gap soil of PDS forests showed a significant increase compared to those in non-gap soil, with increases of 56%–131% for carbon, 107%–1523% for nitrogen, and 100%–155% for phosphorus. There was a significant drop of 10%–33% and 39%–41% in their C:N and C:P ratios, respectively (p < 0.05). The contents of C and P in the gap soil of the Robinia pseudo acacia L. Forest increased significantly, by 14%–22% and 34.4%–71%, respectively. Its C:P and N:P ratios significantly increased, by 14% to 404% and 11% to 41%, respectively (p < 0.05). (3) Compared with NPs, the forest gap significantly reduced the soil electrical conductivity and increased the soil pH. Additionally, compared to the soil at the gap’s edge, the surface soil in the gap’s center had noticeably higher concentrations of C, N, and P. (4) Key variables affecting the soil pH, silt content, bulk density, and overall porosity in forest gaps include the concentrations of carbon (C), nitrogen (N), and phosphorus (P) present and their ecological stoichiometric ratios. The findings showed that forest gaps had a considerable impact on the soil’s physical characteristics and ecological stoichiometry. They also had a high potential for providing nutrients, which might aid in the establishment of plantation plants.

Vegetation restoration can regulate soil microbial habitat and carbon supply by altering soil physicochemical properties. However, it remains unclear how different vegetation restoration patterns influence soil microbial carbon cycling functions through these changes. This study investigated four vegetation restoration models including two coniferous forests —Platycladus orientalis (L.) Franco. (Cupressaceae, PO) and Pinus densiflora Siebold and Zucc. (Pinaceae, PS); one broadleaf forest—Quercus acutissima Carruth. (Fagaceae, QA); and a shrub (SH), using wasteland (WL) as a control. This study employed metagenomic sequencing technology in conjunction with analysis based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The research examined alterations in soil physicochemical characteristics, microbial community structure, and functional pathway associated with carbohydrate metabolism, carbon fixation, and methane metabolism. Vegetation restoration patterns had a strong impact on soil characteristics and microbial composition. Compared to WL, the PO treatment exhibited significant increases in soil organic carbon (SOC, 110.71%), phosphorus (TP, 400%), and bulk density (BD, 22.4%). Significant differences were observed in soil carbon cycle functional pathways, with overall abundance following the trend PO > WL > SH > PS > QA. The relative abundance of carbon fixation, methane metabolism, and carbohydrate metabolism pathways was highest in PO, significantly higher than in QA. Mantel test showed soil phosphorus, pH, and C; N strongly linked to microbial carbon cycling pathways, marking them as key regulators. We found that PO showed the highest abundance of carbon-cycling-related functional pathways, whereas PS showed a comparatively weaker response, suggesting species-specific variation rather than a uniform coniferous–broadleaf pattern. Vegetation restoration controls microbial carbon cycling through soil properties, especially phosphorus, pH, and nutrient balances. This knowledge supports better restoration planning for ecosystem carbon management.