Urbanization is one of the megatrends of the 21 century. Apart from population growth and densification, the most obvious feature is the physical expansion and densification of the built city, which is expanding at twice the speed of the population. However, whether urban growth means the loss of vegetation greenness is still controversial.

Researchers from the Wuhan Botanical Garden of the Chinese Academy of Sciences developed a conceptual framework to empirically quantify the manifestation of urbanization-induced vegetation greenness of 340 cities in the rapidly 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 during the observation period, the two indicators tended to accelerate consistently.

Meanwhile, the researchers 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.

From this perspective, urban planning and sustainable development in Chinese cities achieve their goals under strong and efficient vegetation protection measures.

In conclusion, vegetation degradation is not inevitable in times of urban growth. This is a good sign in terms of environmental challenges, although the quantity of vegetation does not indicate any conclusions to be drawn about vegetation quality.

This study was published in Science of the Total Environment entitled "Does urban growth mean the loss of greenness? A multi-temporal analysis for Chinese cities."