Children in traditional costumes of ethnic groups plant a sapling in Hongqiao Town of Changxing County, east China's Zhejiang Province, on March 12, 2019. Children of different ethnic groups from the central kindergarten of Hongqiao Town took part in a tree-planting activity to greet the Tree Planting Day, also known as Arbor Day, on Tuesday. (Photo:Xinhua)

Children in traditional costume of Miao ethnic group water a sapling in Hongqiao Town of Changxing County, east China's Zhejiang Province, on March 12, 2019. Children of different ethnic groups from the central kindergarten of Hongqiao Town took part in a tree-planting activity to greet the Tree Planting Day, also known as Arbor Day, on Tuesday. (Photo:Xinhua)

Children in traditional costumes of ethnic groups plant a sapling in Hongqiao Town of Changxing County, east China's Zhejiang Province, on March 12, 2019. Children of different ethnic groups from the central kindergarten of Hongqiao Town took part in a tree-planting activity to greet the Tree Planting Day, also known as Arbor Day, on Tuesday. (Photo:Xinhua)

Children in traditional costumes of ethnic groups plant a sapling in Hongqiao Town of Changxing County, east China's Zhejiang Province, on March 12, 2019. Children of different ethnic groups from the central kindergarten of Hongqiao Town took part in a tree-planting activity to greet the Tree Planting Day, also known as Arbor Day, on Tuesday. (Photo:Xinhua)