Lunderberg/Ystesund connection

Hi to the wonder people of this board. Olaf Ystesund moved with his family to the Lundeberg farm near Frydsdal. Then Olaf and his family took the last name of Lundeberg. He was brother to Knute, Ole, Margit, Sigrid, and Kristi Ystesund. Their parents were Aslak and Dagne Ystesund. Why did they do that - take last names of farms or regions? Did they still keep connections with the family they left? Trying to track down more information. Thanks any one for the help.