Future selections

To address the issue of homogenization, the researchers offered several recommendations for cities yet to designate city flowers and trees.

Long suggested the selection be based on local biodiversity and ecological conditions, favoring native species.

"Some cities choose exotic species that do not suit the local environment," he said.

For instance, Western azalea, while beautiful and easy to acquire, is an introduced cultivar and not suitable as a city flower.

"Similarly, cosmos flower, mistakenly called 'Gesang flower' — a flower popular in Tibetan folklore — is actually an invasive species originating from Mesoamerica," he said.

He also emphasized respecting local cultural traditions and the collective memory associated with specific plants. For example, Luoyang is historically known for Chinese peony cultivation, making it an appropriate city flower.

"However, plants like the plum blossom, which hold special cultural significance across many regions in China, should not be universally selected as city flowers," he added.

The study also emphasized the importance of public participation and expert input in the selection process. Beyond consulting cultural, landscaping and artistic communities, cities should seek advice from biodiversity experts and involve residents to ensure the chosen species resonate with the communities.

The researchers' distribution maps of city flowers and trees reveal a clear divide along the Hu Line, reflecting China's uneven socioeconomic development.

Also known as the Heihe-Tengchong Line, the Hu Line is an imaginary line drawn by Chinese geographer Hu Huanyong in 1935. It stretches diagonally across China from the city of Heihe, in the northeastern province of Heilongjiang, to the city of Tengchong in the southwestern province of Yunnan. The significance of the Hu Line lies in its demarcation of the population distribution in China.

East of the Hu Line, the land is more densely populated and includes major cities such as Beijing, Shanghai and Guangzhou in Guangdong province. This eastern region contains about 94 percent of China's population, despite covering only around 43 of the country's land area. In contrast, the vast region west of the Hu Line, which includes the Qinghai-Tibet Plateau and the Xinjiang Uygur autonomous region, is sparsely populated, accounting for only about 6 percent of the population but covering 57 percent of the land area.

Most of the cities without city flowers and trees are west of the Hu Line.

"Only when a city reaches a certain level of economic development do its residents begin to prioritize quality-of-life considerations, such as selecting city flowers and trees," Long explained. "This makes our research particularly valuable, as many Chinese cities have yet to make their choices and can make better choices."

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