"Spring" and "Xuan" are collectively called "Spring Xuan", which means parents.
Toona sinensis is a deciduous perennial tree. In ancient times, it was said that Toona sinensis lived long. Zhuangzi once said that "those who had Toona sinensis in ancient times took 8,000 years as spring and 8,000 years as autumn", which shows their long life span. Therefore, the ancients used it as a metaphor for their father, hoping that his father would live forever like Toona sinensis. Later, all male elders celebrated their birthdays as "Spring Birthdays". Because Kong Li, the son of Confucius, was afraid of disturbing his father's thinking, he hurried across his own courtyard, so the ancients combined the "Spring Pavilion" with the "Listening Pavilion" and called his father "Spring Pavilion". The ancients didn't just call their father "Toona sinensis". After all, it is a tree, but it is called "Xiangchunyuan". Call "Chunxuan" and "Xuan" together as parents. If both parents are alive, it is "Chunxuan Wangwang". The poem "It snows in the spring porch" quoted earlier means that parents are old and their hair is gray.