First off, I have to say that I love the movie Back To The Future a lot and I can't believe I never caught this until now.
At the start of the movie we learn that the mall is called "Twin Pines Mall" and we learn that is because the farmer who sold the property to the mall tried to grow pine trees. When Marty goes back in time and crashes into the barn the farmer starts shooting at him. So he drives off like a mad man and runs over one of the two pine trees the farmer was growing. Then at the end of the movie when Marty returns to the mall the sign says "Lone Pine Mall". Ha Ha, that is great. What cleaver writing.
Speaking of malls, the Dixie Mall in Illinois, where they shot the mall car chase for The Blues Brothers", is finally going to get torn down after all these years. It was a closed-down building even before the movie.