Valencia Summit

The vegetation beyond my fenced backyard is getting dense and taller which increasingly reducing the view. What can I do to address this issue?

You don't state who owns the property were the vegetation is so overgrown.  If it's city-owned property, there are agreements when certain homes on the Summit were built regarding maintenance of growth as related to views.  If your home faces city property call City Hall, and go through the red tape until you finde ther person in charge.