Forest plantations play a critical role in mitigating climate change, with their carbon storage and sequestration capacity significantly influenced by planting patterns. This study focuses on Picea crassifolia plantations in the shallow mountainous region of the Qilian Mountains, aiming to investigate the effects of five planting patterns (pure forests, mixed forests, and uneven-aged forests) on vegetation and soil organic carbon (SOC) dynamics. The research provides a scientific basis for optimizing forest management strategies in arid and semi-arid regions. Fifteen sample plots were established in the Qilian Mountains, Gansu Province, covering five planting patterns: pure forests with 1.5 × 1.5 m (P1.5) and 2 × 2 m (P2) spacing, uneven-aged pure forests (PX), mixed forests of P. crassifolia and Pinus sylvestris var. mongholica (PC), and mixed forests of P. crassifolia, P. sylvestris, and Caragana korshinskii (PPC). Vegetation biomass (tree height, DBH, crown width) and soil samples (0 – 80 cm depth) were collected. Carbon content was determined using the potassium dichromate oxidation method, and carbon stocks were estimated using national biomass models. Statistical analyses (one-way ANOVA) and membership function evaluation were applied to assess carbon sink potential. Results showed that: 1. Planting spacing: The 2 × 2 m pure forest (P2) exhibited higher vegetation-layer carbon storage (10 t·ha⁻¹) compared to the 1.5 × 1.5 m pure forest (P1.5, 5 t·ha⁻¹). 2. Age heterogeneity: The uneven-aged pure forest (PX) showed the highest vegetation-layer carbon storage (6.61 t·ha⁻¹), but its total carbon stock (106.98 t·ha⁻¹) was slightly lower than P2 (111.08 t·ha⁻¹) due to P2’s superior SOC content in deeper soil layers (13.64 g·kg⁻¹ at 60–80 cm). 3. Pure vs. mixed forests: Pure forests (P2) outperformed mixed forests (PC, PPC) in total carbon storage, driven by soil-layer contributions (>95% of total stocks). The 2 × 2 m pure forest (P2) demonstrated optimal carbon sequestration potential in the Qilian Mountains, with soil carbon dominance highlighting the importance of deep-layer SOC accumulation. While uneven-aged forests (PX) showed strong vegetation carbon storage, long-term carbon sinks require integrated soil management. These findings provide critical insights for arid-region plantation configurations. Future studies should combine remote sensing for dynamic carbon monitoring and explore diversified mixed-species systems to enhance ecosystem stability.

Phenotypic variation analysis and comprehensive evaluation are important tools for selecting provenances of forest trees, which, in turn, is crucial for genetic improvement of forest trees. The study analyzed eight needle-leaf and fourteen tracheid trait indexes of ten provenances of Qinghai spruce forest stands. Multiple comparisons, correlation analysis, cluster analysis, and principal component analysis were used to evaluate the differences in needle-leaf and tracheid traits among the different provenances. The study found significant differences in the needle-leaf and tracheid traits among the provenances. All traits included 50 pairs of positive and 26 pairs of negative correlations. The coefficient of variation for the tracheid trait (18.86%) was higher than that for the needle-leaf trait (17.20%). A comprehensive evaluation of needle-leaf and tracheid traits was conducted using principal component analysis. The study demonstrated that the degree of variation in needle-leaf and tracheid traits among the provenances of Qinghai spruce was extensive, with a multitude of sources of variation. Therefore, it is crucial to strengthen the selection of good provenances in the early seed selection process. The results of the comprehensive evaluation can be utilized as a foundation for the selection of good provenances for carbon sequestration and timber properties.

Megastigmus sabinae Xu et He (Hymenoptera: Torymidae) is an oligophagous seed pest overwintering within Juniperus przewalskii cones in the alpine Qilian Mountains. Understanding its cold adaptation is critical for forest pest management. To investigate its overwintering mechanisms, we monitored field temperatures and larval development. Subsequently, larvae were subjected to a series of low-temperature treatments under laboratory conditions. We then assessed survival rates, supercooling points (SCPs), free water content, and the transcriptomic profiles of water-regulatory genes. Field data revealed that larvae enter a quiescent state when ambient temperatures drop below 5 °C. Laboratory acclimation at 0 °C significantly improved larval survival at −10 °C and markedly depressed the SCP by approximately 6 °C. Notably, free water content remained completely stable across all temperature treatments. Consistent with this dehydration-independent phenotype, transcriptomic analysis showed that the majority of 17 aquaporins (AQPs) and a Capa receptor gene lacked differential expression. However, two specific AQP genes (TIP1-1 and AQPN) were significantly upregulated. Collectively, M. sabinae larvae employ a freeze-avoidance strategy driven by dehydration-independent SCP depression and highly targeted transcriptional adjustments of specific water channels.