Seasonal Satellite Images Help Map Shrub Cover in Inner Mongolia
03 Nov 2026
Researchers from the Aerospace Information Research Institute of the Chinese Academy of Sciences (AIRCAS) have used satellite images taken across the growing season to map shrub cover in the grasslands of Inner Mongolia. Tracking seasonal differences in growth helped them distinguish shrub patches from dense grass, which can look similar in a single image.
As shrubs spread into semi-arid grasslands, they can change which plants grow there and how much forage is available to livestock. Mapping shrub cover can help land managers track that spread.
The earliest stages of encroachment are also the hardest to detect. Where shrubs are small and scattered, a satellite pixel can contain a mix of shrubs, grasses, and bare soil.
The team tested its method in grasslands near Xilinhot in northern China's Inner Mongolia Autonomous Region. The researchers combined PlanetScope images at 3-meter resolution with a deep learning model called U-Net and checked the resulting estimates against drone surveys and very high-resolution imagery.
The fine spatial detail allowed the model to capture the shapes of shrub patches. By combining observations at 15-day intervals, the model could also use differences in when shrubs and grasses grew. Compared with imagery from a single period, the seasonal observations increased the proportion of variation in shrub cover that the model could explain (R²) by about 17%.
The model also preserved fragmented shrub patches better than methods that estimated cover one pixel at a time. Its estimates were less reliable for plots excluded from training, and sparse shrubs remained difficult to detect.
Shrub cover estimated from PlanetScope imagery using U-Net and from Sentinel-2 imagery using XGBoost. The PlanetScope estimates show the fragmented shrub patches in greater detail. (Image by AIRCAS)
More reliable estimates at low shrub cover would help grassland managers identify encroachment while shrubs are still scattered.
Research News
Seasonal Satellite Images Help Map Shrub Cover in Inner Mongolia
Researchers from the Aerospace Information Research Institute of the Chinese Academy of Sciences (AIRCAS) have used satellite images taken across the growing season to map shrub cover in the grasslands of Inner Mongolia. Tracking seasonal differences in growth helped them distinguish shrub patches from dense grass, which can look similar in a single image.
The study was published in the International Journal of Digital Earth.
As shrubs spread into semi-arid grasslands, they can change which plants grow there and how much forage is available to livestock. Mapping shrub cover can help land managers track that spread.
The earliest stages of encroachment are also the hardest to detect. Where shrubs are small and scattered, a satellite pixel can contain a mix of shrubs, grasses, and bare soil.
The team tested its method in grasslands near Xilinhot in northern China's Inner Mongolia Autonomous Region. The researchers combined PlanetScope images at 3-meter resolution with a deep learning model called U-Net and checked the resulting estimates against drone surveys and very high-resolution imagery.
The fine spatial detail allowed the model to capture the shapes of shrub patches. By combining observations at 15-day intervals, the model could also use differences in when shrubs and grasses grew. Compared with imagery from a single period, the seasonal observations increased the proportion of variation in shrub cover that the model could explain (R²) by about 17%.
The model also preserved fragmented shrub patches better than methods that estimated cover one pixel at a time. Its estimates were less reliable for plots excluded from training, and sparse shrubs remained difficult to detect.
Shrub cover estimated from PlanetScope imagery using U-Net and from Sentinel-2 imagery using XGBoost. The PlanetScope estimates show the fragmented shrub patches in greater detail. (Image by AIRCAS)
More reliable estimates at low shrub cover would help grassland managers identify encroachment while shrubs are still scattered.