Daraenamu Tree in Changdeokgung Palace is estimated to be 600 years old, meaning it had likely been planted before the palace was built. The tree stands 19m in x_height, and has six separate trunks sprawling in all directions. It is the biggest and the oldest in Korea. It is designated and protected as a National Natural Monument.
Source: Korea Tourism Organization official English tourism database. Opening hours and details can change — check the official website before visiting.