Organization:Wuhan Botanical Garden
Multi-temporal Analysis: Urbanization Doesn't Induce Definite Vegetation Loss
Urbanization is one of the megatrends of the 21st Century. Apart from population growth and densification, the most obvious feature is the physical expansion and densification of the built city, which expands at twice the speed of the population. However, whether urban growth means the loss of vegetation greenness is still controversial.
Researchers from Wuhan Botanical Garden designed a conceptual framework for empirically quantifying the manifestation of urbanization-induced vegetation greenness of 340 cities in the quickly urbanizing nation of China based on time-series MODIS EVI products from 2003 to 2018 and urban land data from the authoritative NLUD-C during 2000-2015 with five-year intervals.
The comparative analysis showed that although vegetation greening generally lagged behind urban growth in the monitoring period, the two indicators tended to consistently speed up. Meantime, results of the study revealed the diversity of urban growth and its contemporary vegetation greenness dynamics.
Both the forms and trends of vegetation greenness related to urban growth were recognized as four categories. Despite the partial cities presenting decreasing vegetation greenness, there are still a large proportion of cities were measured to have increasing vegetation greenness, i.e., over 85.88 % adopting “UU”(from up to up) or “DU”(from decrease to increase) vegetation greenness dynamic forms, over 82.35 % adopting “Type A”(High areal proportions of greenness increasing trend in both the existing urbanized area and new urbanized area) or “Type C” (High areal proportions of greenness increasing trend in the existing urbanized area and low areal proportions of greenness increasing trend in the new urbanized area) vegetation greenness dynamic trends. In this perspective, urban planning and sustainable development in Chinese cities achieves its goals under strong and efficient vegetation protection measures.
In conclusion, vegetation degradation is not inevitable in times of urban growth. This is initially a good sign with respect to the environmental challenges, even though vegetation quantity does not allow any conclusions to be drawn about vegetation quality.
This study has been published in Science of the Total Environment entitled "Does urban growth mean the loss of greenness? A multi-temporal analysis for Chinese cities" . Researchers from German Aerospace Center, German Remote Sensing Data Center, and Aerospace Information Research Institute of the Chinese Academy of Sciences also participate in the study.