India, May 15 -- The age of the trees and who else has seen them - these were two questions US President Donald Trump asked, as his Chinese counterpart Xi Jinping took him to the walled-off Zhongnanhai compound, a secret garden that houses key government offices.

Centuries-old trees dominated the conversation - or at least the parts caught on a hot mic - in Beijing's former imperial garden where Trump and Xi strolled in the concluding hours of their summit.

The garden now houses the offices of the ruling Communist Party and the state council, or China's cabinet. It is adjacent to the capital's famed landmark of the Forbidden City and just off Tiananmen Square.

"Let me tell you, all the trees on this side are over 200 to 300 years old,"...