October 18, 2017

Reforestation in China: wooded areas at the Yellow River have increased by 44%

The catchment area of the Yellow River (Chinese: Huang He) – at 750,000 square kilometres the second largest drainage basin in China – is the foundation for the livelihood of almost 190 million people. This livelihood is endangered by excessive use. An EOC analysis shows the progress being made thanks to Chinese countermeasures.

The Huang He river basin is one of China’s most important and dynamic economic regions. Wide-ranging reforms here stimulated the transition from an agricultural to an industrial and service-oriented economy. Fast-paced economic growth led to a decade of overexploitation of the natural land and water resources. Water scarcity, soil degradation and environmental pollution accordingly threaten the long-term and sustainable development of the region. To give just one example, many forested regions in the hinterlands of the Yellow River were converted into arable land and pastures, which furthered extensive soil erosion. In order to end this massive soil loss, already in 1995 China began implementing at the middle and upper courses of the Yellow River the world’s most far-reaching ecological restoration measures, and at the local level promoted sustainable, localized agriculture.

An EOC analysis now shows the progress resulting from these efforts. Images collected by optical satellite sensors were used to document the reforestation measures of the last few decades on the Loess Plateau at the middle course of the Yellow River. Satellite images from the Landsat mission provided the data fundament. Because they extend back to 1972 they are eminently suitable for identifying historical changes with high resolution. The image below shows in different shades of green the rapid increase in the extent of forested areas. These areas have increased by 44 percent on the Loess Plateau since 2000 —from 26,000 to 33,000 square kilometres, whereby especially hillsides with slopes exceeding 15 degrees were reforested. This area is roughly eight times the size of Berlin. These measures led to a significant reduction in soil erosion. At the same time, local agricultural yield could be considerably increased.

The EOC data and analyses have been made available to Yellow River authorities to support the goal of achieving sustainable land and water management in the Yellow River drainage basin. The time-series analyses are an important information resource for regional and local decision makers. EOC develops methodologies for assessing large masses of data, like what accumulates in long time series, to make possible rapid and efficient analyses of this type.

Original Research:
Wohlfart, C., Liu, G., Huang, C. Kuenzer, C. A river in the course of time - Multi-temporal analysis of land surface dynamics in the Yellow River Basin (China) based on medium resolution remote sensing data. Remote Sensing. 2016, 8 (3) 186; doi:10.3390/rs8030186

Wohlfart, C., Mack, B., Liu, G., Kuenzer C. Multi-faceted land cover and land use change analyses in the Yellow River Basin based on dense Landsat time series: Exemplary analysis in mining, agriculture, forest, and urban areas. Applied Geography. 2017, 85, doi: 10.1016/j.apgeog.2017.06.004


Univ. Prof. Claudia Künzer

Head of Department
German Aerospace Center (DLR)
German Remote Sensing Data Center (DFD)
Land Surface Dynamics
Oberpfaffenhofen, 82234 Weßling
Tel: +49 8153 28-3280