There was a tree in from of Oswald with leaves that blocked his view to a degree. And he wasn’t the shooter anyway.
There was a tree. After the motorcade turned left at Dealy Plaza. But there were no trees, no obstruction at all as JFK was going down Main St.
https://commons.wikimedia.org/wiki/File:6th_Floor_Window_View.jpg
This fact that Oswald didn’t shoot then does gives credibility that while Oswald did shoot Kennedy, he did it fire the fatal shot. That shot came from the Grassy Knoll.