Estimation and Spatial Distribution of <italic>Hippophae rhamnoides</italic> Biomass in the Ecological Sand Reduction Engineering Area

Estimating the biomass of Hippophae rhamnoides of the Shidakongdui ecological sand reduction projects in the Shanxi-Shaanxi-Mongolia area is crucial for accurately assessing the carbon sequestration effects of artificial Hippophae rhamnoides ecological projects. 112 plots biomass data of artificial Hippophae rhamnoides were collected from field surveys and data mining in the Dongsheng area of Inner Mongolia from 2013 to 2018. Pearson correlation analysis was employed to determine the related environmental variables, and a biomass estimating model was established by using time-series environmental variables (July-September annually from 2019 to 2023) and the spatial distribution of artificial Hippophae rhamnoides biomass was discussed. Results: (1) The artificial Hippophae rhamnoides biomass increases with ages, primarily influenced by precipitation (P), normalized vegetation index (NDVI), leaf area index (LAI), sunshine duration (h), and soil moisture content (SWC). (2) Using time-series data can effectively improve the accuracy of biomass estimation and the optimal estimation model is W=7.65×P+268.62×NDVI+891.82×SWC+3.28×h+29.56×LAI–1190.55. (3) The maximum, minimum, and average amount of artificial Hippophae rhamnoides biomass in the Shidakongdui ecological sand reduction projects in the Shanxi-Shaanxi-Mongolia area are 135.71, 0.03 and 26.52 tons, respectively, and an average biomass per plot was 18.22 tons; the spatial distribution of the biomass showed a decreasing trend from southeast to northwest, greatly influenced by rainfall, normalized vegetation index, and sunshine duration.