What did pine and cypress mean in ancient times?

People in China have special feelings for pine trees since ancient times. They often use pine and cypress to symbolize their unyielding character, and regard pine, bamboo and plum as "three friends of the old cold"

"The Analects of Confucius" Zi Han said: "Cold knows the decline of pines and cypresses." Later books of songs often used pine and cypress to symbolize honest and frank aloof character. Liu Yuxi: "Later, wealth faded, and cold pines and cypresses still existed." Li Shanpu: "There is a lonely horn in the snow and a howling in the wind. It's really embarrassing for Tao Li to denigrate him, and rattan is not a group. "