Abstract
Efficient vegetation planting is essential in highway construction to reduce greenhouse gas emissions and prevent ecological degradation. However, carbon sequestration has rarely been considered in previous optimization models for planting strategies in these environments. To address this gap, this study focuses on selecting five predominant shrub species—Ailanthus altissima, Robinia pseudoacacia, Vitex negundo var. heterophylla, Amorpha fruticosa, and Lespedeza bicolor—typical of the Linyi section of the Beijing-Shanghai Expressway. The study quantifies the carbon sequestration rates and water consumption of these species to demonstrate their contribution to climate change mitigation. Field data were collected in spring, summer, and autumn using the LI-6800 portable photosynthetic system. The NSGA-II was subsequently adopted to establish an optimal model, considering constraints of a planting area of 1000 m² and a water consumption limit of 1067.9 mm. Based on the recorded datasets and the implementation of NSGA-II, the optimized vegetation planting structure for this area comprised Ailanthus altissima (21%), Robinia pseudoacacia (30%), Vitex negundo var. heterophylla (11%), Amorpha fruticosa (26%), and Lespedeza bicolor (12%). By adopting this novel solution, the carbon sequestration capacity per square kilometer increased by 541 kg, while water consumption decreased by 104 mm. This manuscript exemplifies achieving a balance between ecological and economic benefits through an optimized and targeted vegetation planting structure on highway slopes. Local and national authorities can use these results to implement similar strategies in different areas.