Is the hall of supreme harmony in the Forbidden City particular about geomantic omen?
First, there are no trees in the third hall and the third palace, which can reduce many security risks. During the Jiaqing period, Lin Qing led the uprising of the "Tianlijiao" rebel army. At that time, the rebel army broke into the Forbidden City and climbed over the palace wall by climbing trees until it was outside the emperor's palace. Fortunately, the army arrived and captured the invading rebels. Jiaqing was furious and cut down all the trees in the three halls and the last three palaces to prevent assassins from hiding.
Second, feng shui taboo. The Forbidden City is laid out according to geomantic omen. The three halls belong to the soil, and the wooden soil is equivalent to restraining the imperial power. As the most solemn place, the Forbidden City pays more attention to Feng Shui than other places. According to the geomantic omen and the five elements of Yin and Yang, the three halls in the center of the Forbidden City belong to the earth, so it is natural not to plant broken wood, so as not to oppress the emperor's authority and break the supremacy of imperial power.
Third, the emperor is a real dragon emperor and can't be trapped. The whole Forbidden City is a closed "mouth". If trees are planted in the three halls and the last three palaces, it is a word "sleepy". But how can the emperor be trapped in the palace is the taboo of the emperor? Therefore, there are no trees in the three halls and the last three palaces near the emperor.