为什么说“梧桐一叶落，天下尽知秋”（二十四节气二十四问）

Group 1 - The article discusses the significance of the "Liqiu" (Beginning of Autumn) solar term, which marks the transition from summer to autumn, starting on August 7, 2025 [2] - "Liqiu" symbolizes the maturity of crops and the onset of the harvest season, indicating the end of the hot summer [2] - The phrase "a leaf falling from the parasol tree signifies the arrival of autumn" reflects ancient people's sensitivity to seasonal changes, with historical references tracing back to classical texts [3][4] Group 2 - The parasol tree (Wutong) is highlighted as a cultural symbol associated with autumn, recognized for its large leaves that are sensitive to climate changes, making it an early indicator of the season [3][4] - The article emphasizes the aesthetic and cultural significance of the parasol tree, which is considered a symbol of good fortune and purity in ancient Chinese literature [5] - The modern understanding of seasonal changes through technology contrasts with the traditional wisdom encapsulated in the phrase "a leaf falling" that continues to resonate in contemporary culture [5]