In Tehilim 72 says mountains bring peace for nation and jills bring righteousness how to understand it?

ב"ה Shalom There is not only one way to understand this verse. Sometimes different commentators will take different approaches. To make things short and simple I will quote two commentaries. The Radak and Meiri. The Radak says that the verse is a parable, and the mountains and hills refer to the nations of the world who will deal peacefully and justly in the time of Shlomo . The Me'iri. He explains "mountains will bring peace for nations and the hills will bring charity", means that there will be an economic prosperity through the mountains and and hills which will carry an abundance of food. All the best