A couple of years ago I planted a plot of apples and persimmons. They seem to be doing well.

They are on a hillside from a highway. Further back is a barn that is in view of the highway. It has been broken into twice in the last couple years.....as it appears an easy target of opportunity from the highway.

I intend to plan 50 loblollies on the barn side of the fruit trees to screen it from the road. I don't have a whole lot of space to work with, but enoght to get in the loblollies and leave a doublewide tractor lane between the trees and the barn. What is the least amount of space I should leave between the pines and the fruit trees, in order to keep the fruit trees healthy as the pines grow? Is 15' enough?