Vegetation Greening in Response to Ecological Restoration Programs in Shaanxi Province, China

Abstract

Vegetation constitutes the structural backbone of terrestrial ecosystems, regulating carbon exchange, water cycling, and energy flux at regional scales. The Normalized Difference Vegetation Index (NDVI), derived from satellite remote sensing, provides a robust proxy for vegetation vitality and has been extensively adopted in long-term ecological monitoring. This study examines the spatio-temporal dynamics of vegetation coverage across Shaanxi Province, northwestern China, over the period 2000–2019, using MODIS MOD13C1 NDVI data. Growing-season (May–October) composites were generated via the Maximum Value Compositing (MVC) method, and pixel-wise temporal trends were quantified through ordinary least-squares regression. Results indicate: (1) spatially, vegetation coverage follows a pronounced south-to-north declining gradient, with high-coverage zones (NDVI > 0.6) concentrated along the southern Qinling foothills and northern Daba Mountains, representing approximately 32.85% of the provincial area; (2) temporally, provincial mean NDVI increased from 0.4488 in 2000 to 0.5405 in 2019, an overall gain of ~20.4%; (3) 98.07% of pixels exhibited positive trends, concentrated in central-southern Shaanbei where afforestation programs were intensively implemented, while declining trends (~1.93%) were confined to the Guanzhong urban agglomeration, attributable to cropland conversion and urban expansion. These findings offer a quantitative baseline for regional ecological assessment and policy evaluation in Shaanxi Province.