Forest management practices reshape microbial diversity and co-occurrence network stability through environmentally mediated regulatory mechanisms
Description
The study was conducted at Jiulongshan, a part of the North China Forest Research Center of the Chinese Academy of Forestry (115°59′–116°07′E, 39°54′–39°59′N; elevation 100–997 m). This center is situated in the eastern Taihang Mountains near Beijing (see Fig. 1). The region experiences a temperate continental monsoon climate, characterized by an average annual temperature of 11.8 °C and mean annual precipitation of approximately 630 mm, with a total annual evaporation of about 1870 mm. The soil is classified as brown mountain forest soil with a high gravel content. The dominant vegetation comprises temperate mixed forests of coniferous and broad-leaved species, primarily including Pinus tabuliformis, Platycladus orientalis, and Quercus variabilis (Zhang et al., 2022). In spring 2019, twenty permanent sample plots (30 m × 30 m each) were established within a Pinus tabuliformis plantation at Jiulongshan Forest Farm. These plots were selected to ensure comparable topographic and site conditions. All trees within each plot with a diameter at breast height (DBH) of ≥5 cm were georeferenced using a Topcon GTS602 total station (Topcon, Tokyo, Japan). Tree species were identified, and measurements were taken for DBH, height, and crown diameter. To mitigate edge effects, a 3-meter buffer zone was established within the perimeter of each plot. Key plot characteristics are presented in Table 1. In the winter of 2019, structured forest management (SBFM), close-to-nature forest management (CNFM), and randomized forest management (RFM) were applied to plots SBFM1–SBFM5, CNFM1–CNFM5, and RFM1–RFM5, respectively. Plots that received no silvicultural intervention served as controls (CK). Soil samples were collected in August 2024 to analyze their physicochemical and biochemical properties. After removing fresh and partially decomposed surface litter, samples were taken from the 0–10 cm soil layer. In each plot, five soil cores were extracted along an S-shaped transect using an 8 cm diameter stainless steel corer. Following the removal of stones and visible roots, the cores were homogenized into a single composite sample. A total of 20 composite samples were obtained.