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.
He DIDN'T fire......
There were other places triangular shots could have been made in that kill zone.
Senator Richard Russell was the only member of the Warren Commission to go to Dallas and examine Dealy Plaza and the 6th floor of building. He wrote a 32 page dissent of the Warren Commission findings and did not think Oswald could have possibly pulled that off.