What do you mean, a thousand-year-old tree?

"Planting trees for a thousand years, educating people for a hundred years" is a metaphor, which means that it takes a long time to cultivate a good person, just like cultivating trees. It emphasizes the importance of education and training, and expresses that human beings should cherish time and resources and try their best to cultivate and develop human abilities and wisdom for the benefit of society and mankind.