On the way back to the mountain city, Zheng Yaoxian showed him Populus euphratica, which is called the "tree of immortality" by the roadside. This kind of tree can resist the high temperature of MINUS 40 degrees and the cold of MINUS 40 degrees, and is not afraid of saline-alkali and sandstorm. One Populus euphratica can fix one mu of sand. In order to fight against the harsh environment, it firmly plunged its roots into the sand, gathered a big sandbag at the roots, formed its own highland, and drew energy from it, creating a life that would not die for thousands of years, never fall after death, and never rot for thousands of years. Ma Xiaowu knows that his master, like this Populus euphratica tree, has created an immortal myth with his perseverance in the hard environment of nearly forty years.