There is a dearth of research regarding the windbreak and sand stabilization functions of Caragana liouana shelter forests in the Gonghe Basin of the Qinghai-Tibet Plateau. Therefore, the aim is to elucidate the patterns of near-surface wind–sand activity in artificial Caragana liouana forests of varying ages and mixed forests of different configurations in alpine sandy areas. Additionally, this research seeks to clarify the windbreak and sand fixation effects of these forests. To this end, we have selected artificial forests of Caragana liouana of varying ages (10-year-old pure Caragana liouana forest (10aZJ-C), 17-year-old pure Caragana liouana forest (17aZJ-C), 37-year-old pure Caragana liouana forest (3aZJ-C)) and shrub mixed forests of different mixing modes (10-year-old Caragana liouana and Caragana korshinskii mixed forest (10aNZ-HJ), 10-year-old Caragana liouana and Artemisia desertorum mixed forest (10aSZ-HJ), an 10-year-old Caragana liouana and Salix cheilophila mixed forest (10aWZ-HJ)) within the Sand Control Station of Shazhuyu Village in the Gonghe Basin of the Qinghai-Tibet Plateau as the research subjects. Naked sand dunes were used as the control plot (CK), and through field observations of the wind speed profile, sand transport rate, and micro-topographic changes of each stand plot, we analyzed the wind–sand flow structure characteristics and sand transport process of Caragana liouana of different ages and their mixed forests, eventually proposing suitable afforestation configuration modes for the alpine sand area of the Gonghe Basin in Qinghai. The findings indicate that the wind speed profile within each stand plot follows a linear distribution pattern. Compared to naked dune land, the windbreak effect of each plot decreases as the height from the ground increases. Among them, the 10aWZ-HJ plot significantly alters the wind speed profile and has a substantial windbreak effect; at a height of 200 cm, the windbreak effect can still reach 41.27%. The sand transport rate of each plot fits into an exponential function relationship, with the correlation coefficients (R²) of the fitting equations for each plot all exceeding 0.95 and significantly lower than the control plot, suggesting vegetation can effectively reduce near-surface sand transport. The sand-fixing effects at the height of 0–45 cm from the ground in each plot are as follows: 37aZJ-C > 17aZJ-C > 10aWZ-HJ > 10aNZ-HJ > 10aZJ-C > 10aSZ-HJ. Overall, all plots indicate a state of accumulation. The 10aWZ-HJ plot has the largest relative accumulation area at 88.00%, and the highest average intensity of wind erosion and accumulation at 1.11. Taking into account the stability of the stand and the total protection time, this study suggests that it is suitable to mainly use mixed forests of Salix cheilophila and Caragana liouana in the alpine sand area of the Qinghai-Tibet Plateau. The results of this study can provide a theoretical basis for the construction of windbreak and sand-fixing forests in alpine sand areas.

Global climate change has intensified land desertification in the arid and semi-arid regions of northwestern China, highlighting the urgent need to cultivate plant species with ideal architecture and well-developed root systems to combat ecosystem degradation. Amorpha fruticosa is widely used as a windbreak and sand-fixation shrub; however, its rapid growth and high transpiration during the early planting stage often result in excessive water loss, low survival rates, and limited vegetation restoration effectiveness. Plant growth retardants (PGRts) are known to suppress apical dominance and promote branching. In this study, one-year-old A. fruticosa seedlings were treated with different combinations of paclobutrazol (PP₃₃₃) and uniconazole (S₃₃₀₇) to investigate their effects on plant morphology and biomass allocation; it aims to determine the optimal formula for cultivating shrub structures with excellent windbreak and sand-fixation effects in land desertification areas. The results showed that both PP₃₃₃ and S₃₃₀₇ significantly inhibited plant height while promoting basal stem diameter, branching, and root development. Among all treatments, the S₃₃₀₇ 200 mg·L⁻¹ + PP₃₃₃ 200 mg·L⁻¹ combination (SD3) was the most effective, resulting in the greatest increases in basal diameter, branch number, total root length, and root-to-shoot ratio, while significantly reducing height increment, leaf length and leaf area (p < 0.05). Under the S₃₃₀₇ 200 mg·L⁻¹ + PP₃₃₃ 300 mg·L⁻¹ treatment (SD4), leaf width and specific leaf area were reduced by 17.92% and 38.89%, respectively, compared with the control. Correlation analysis revealed significant positive or negative relationships among most growth traits, with leaf length negatively correlated with other morphological indicators. Fresh and dry weights of both aboveground and root tissues were significantly positively correlated with basal diameter (R = 0.38) and branch basal diameter (R = 0.33). Principal component analysis demonstrated that the SD3 treatment achieved the highest comprehensive score (2.91), indicating its superiority in promoting a compact yet robust plant architecture. Overall, the SD3 treatment improved drought resistance and sand-fixation capacity of A. fruticosa by “dwarfing and strengthening plants while optimizing root–shoot allocation.” These findings provide theoretical support for large-scale cultivation and vegetation restoration in arid and semi-arid regions and offer a technical reference for growth regulation and windbreak and sand-fixation capacity in other xerophytic shrub species.