The Forbidden City, also known as the Forbidden City, was a place for emperors to govern and live during the Ming and Qing dynasties. There are four gardens in the Forbidden City: Imperial Garden, Cining Garden, Jianfu Palace Garden, and Qianlong Garden. Among them, there are elm trees planted behind Kunning Gate in Imperial Garden, east side of Yanshou Hall in Cining Garden, in front of Jicui Pavilion in Jianfu Palace, and in front of Guhua Pavilion in Qianlong Garden. In late spring, a tree blooms with flowers. The nameplate on the tree (produced by Beijing Municipal Bureau of Landscape and Greening in 2017) shows that the planting year of the catalpa tree in Yuhuan and Cining Garden is around the 45th year of the Wanli reign (1617); The planting year of the catalpa tree in Jianfu Palace is around the 22nd year of Jiaqing (1817); The catalpa tree in front of Guhuaxuan was planted around the sixth year of Kangxi's reign (1667). The Chinese catalpa tree is a deciduous tree species belonging to the Zizania family and the Zizania genus. It is an ancient tree species unique to China. The catalpa tree is tall and straight, with triangular ovate leaves, pink purple bell shaped flowers with yellow striped purple spots, and slender linear capsules. Why do the gardens of the Forbidden City prefer to plant catalpa trees? Since ancient times, the Chinese catalpa tree has had the attribute of "precious wood". In Chinese history, catalpa trees have been commonly found in palace gardens and feudal courtyards, and are a symbol of aristocratic etiquette and status. For example, in The Book of Songs, Xiaoya Zhanlu, it says: "Its trees and chairs are actually separated from each other, and no one can fail to make an order." The main idea of this sentence is: wutong and catalpa trees in the court are full of fruits; A harmonious gentleman has a dignified demeanor. This poem reflects that as early as the Spring and Autumn Period, the catalpa tree was a common tree in the gardens of nobles and nobles. The "chair" in the poem refers to the catalpa tree. In Guifu's "Shuowen Jiezi Yizheng" (Volume 16) of the Qing Dynasty, it is recorded that "chairs and catalpa trees are the same." Similarly, in Cao Zhi's "Cao Zijian Ji" (Volume 6) of the Three Kingdoms period, it is recorded that "cockfighting takes place on the eastern outskirts of the road, and horses run among the rows of catalpa trees. Here, 'Changjuan' refers to the endless path of elm trees, which is a landmark landscape of the royal gardens and imperial streets of Luoyang City during the Han and Wei dynasties. For example, in Yang Xuanzhi's "Luoyang Galan Ji" (Volume 1) of the Northern Wei Dynasty, it is recorded: "The six mansions are all high gate and magnificent houses, with spacious pavilions and paths shaded by elm trees and locust trees." This means that the mansions of six important officials of the Northern Wei Dynasty, including Changsun Zhi, are all high gate buildings and magnificent buildings, with spacious and magnificent study rooms and halls, and the dense shade of elm trees and locust trees covers the roads. The Forbidden City was the imperial palace of the Ming and Qing dynasties, and the gardens in the palace were planted with "precious wood" catalpa trees, highlighting the supreme and noble status of the Ming and Qing emperors and highly fitting with the royal aura. In line with the royal atmosphere of the Forbidden City, all four gardens in the Forbidden City are planted with catalpa trees, which are in line with the royal atmosphere of the Forbidden City, mainly manifested in three aspects. Firstly, the purple color of the Chinese parasol tree echoes the imperial symbolism of the Forbidden City. The ancients believed that purple was an auspicious and noble color. The catalpa tree in the palace blooms in late spring, with a purple red color that looks like "purple energy coming from the east" from afar, giving a strong sense of auspiciousness and fitting the imperial atmosphere of the Forbidden City. The allusion of "Purple Qi Coming from the East" originated from Liu Xiang's "Biography of Immortals" (Volume One) in the Western Han Dynasty. Among them, there is the saying 'Laozi traveled westward and was pleased to first see his spear, knowing that a real person had passed by. He searched and covered it up, and obtained Laozi.' This means that when Laozi traveled westward and was about to pass through Hanguguan (now Hanguguan Town, Lingbao City, Sanmenxia City, Henan Province), Yin Xi saw a purple aura coming from the east in advance and knew that a real person would pass by. Based on this sign, he waited to welcome Laozi and indeed arrived. Here, Laozi is the founder of the Taoist school, and Yin Xi is the first successor of Laozi's ideas. It can be seen that the arrival of "Purple Qi from the East" signifies the arrival of saints and immortals, which is in line with the identity of the Emperor of the Forbidden City as the "Son of Heaven" and the concept of "divine right of kings", symbolizing the sanctity of imperial power and the prosperity of the country. The plaque "Purple Qi Comes from the East" on the Phoenix Tower of the Shenyang Imperial Palace was inscribed by Emperor Qianlong. Secondly, the tall and flourishing elm flowers adorn the royal garden environment. The catalpa tree in the Forbidden City has a towering crown that softens the rigid lines of the palace. The red walls, yellow tiles, and purple flowers and green trees complement each other, creating a royal garden atmosphere that combines strength and softness with elegant colors, making it grand yet elegant. The Chinese catalpa flowers are located at the top of the trees, complementing the low growing peonies, peonies, and other flowers, enriching the viewing space of the royal garden. The emperor and empress residing in the palace, in their leisure time, looked up and saw purple flowers towering like clouds, which immediately made them pleasing to the eye. Not only that, the purple beauty of the catalpa flower also meets the aesthetic needs of the emperor and empress for noble and auspicious colors. This scene of "auspicious signs hanging from the sky and purple clouds surrounding the palace" not only embellishes the royal garden landscape, but also reflects the emperor's wishes for national prosperity and people's peace. The third is that the catalpa tree is tall and strong, with a long age, which is in line with the auspicious meaning of the Ming and Qing royal families. The Chinese catalpa tree is tall and straight, with a straight main trunk, a dense and tight crown, and a majestic posture. In Lu Dian's "Piya" (Volume 14) of the Song Dynasty, it is recorded: "The old saying goes: the chair is the catalpa, and the catalpa is the catalpa... Nowadays, the peony is called the king of flowers, and the catalpa is the king of wood. Covering the catalpa with wood is not good." This passage reflects that the catalpa tree has excellent material and performance, and is a high-quality tree species in the eyes of ancient people; The Chinese catalpa tree is known as the "King of Trees", which reflects its high status and respect among trees, and is in line with the solemn and noble atmosphere of royal gardens. In the Ming Dynasty, Niu Zhongzeng's "Zengxiu Piya Guangyao" (Volume 25) added that "the catalpa tree is a beautiful wood. The stem is tall and slender, and the clouds are lovely." The catalpa tree is a beautiful wood (king of wood), mainly because its trunk is tall and straight, towering into the clouds, and its posture is upright and beautiful, which is pleasing to the eye and loved by people. The Chinese catalpa tree is a typical long-lived tree species, with a natural lifespan of several hundred to over a thousand years. The ancient Chinese elm tree in front of Fusu Temple in Dalin Township, Yuanping City, Xinzhou City, Shanxi Province, has a history of over 2000 years and is known as the "number one Chinese elm tree". The catalpa trees in the Forbidden City are also over 300 years old. The longevity characteristic of the Chinese catalpa tree has a strong cultural significance in the Forbidden City. During the Ming and Qing dynasties, the Chinese catalpa tree in the palace symbolized the long-lasting prosperity of the country; The planting of catalpa trees in the Ming Dynasty and the continuation of protection in the Qing Dynasty symbolize the inheritance of the dynasty; For the emperors of the Ming and Qing dynasties, it also implied a self expectation of "virtue matching heaven and earth, longevity matching heaven and earth". It is not difficult to see that the catalpa tree met all the auspicious symbolic needs of the royal family during the Ming and Qing dynasties. The ancient Chinese catalpa tree in front of the Huaxuan became the historical record of the "Jiapeng" catalpa tree in the Forbidden City by Emperor Qianlong, mainly found in his poetry and literature, and all of them are the ancient Chinese catalpa trees in front of the Huaxuan. The Guhua Pavilion is located in the first courtyard of the Qianlong Garden, built in the 41st year of the Qianlong reign (1776). In front of the pavilion is an ancient Chinese elm tree, which was planted at least during the Kangxi period. Emperor Qianlong regarded him as a "good friend" and wrote many poems with symbolic praise. There is a couplet inscribed by Emperor Qianlong inside the Guhua Pavilion, which reads: 'The clear breeze of the bright moon hides endlessly, and the long elm and ancient cypress trees are the best companions.'. Emperor Qianlong regarded the clear breeze of the bright moon as an inexhaustible spiritual wealth, and the long elm and ancient cypress trees in front of the ancient Huaxuan as close friends, reflecting his love for nature and friendship with ancient trees. For example, in the poem "Gu Hua Tang" (Qianlong 47th year, 1782), it is written: "Cypress stands firm and never withers, while catalpa trees are accompanied by branches. Between the combs of young children, they are like envious companions in a gathering season." Emperor Qianlong explained in his poem: "Cypress trees are strong and never wither, and catalpa trees also have new branches to accompany them as friends; Cypress and elm trees have lush and dense branches and leaves, just like a gathering of world-renowned experts. For example, in the poem "Inscription on the Ancient Hua Xuan" (Qianlong 49th year, 1784), it is written: "Taking simplicity as the essence of the present is the essence of the past, inspiring the poet to recite and cultivate in the pavilion." Emperor Qianlong believed in the poem that the Chinese catalpa tree is beautiful for its simplicity, which inspired him to compose poetry and prose, making him his spiritual confidant and poetic friend. From the above, it can be seen that all four gardens in the Forbidden City are planted with Chinese catalpa trees, which is not only due to the excellent endowment characteristics of Chinese catalpa trees, but also closely related to the profound cultural symbolism of imperial power they contain. These catalpa trees have also become tangible witnesses to the long history and culture of the Forbidden City. (Looking into the New Era) (Author: Zhou Qian, a research curator at the Palace Museum)