I believe it's line of site.... The trees are closer and taller as to pan to towards due west.... I have no idea how I pull in 119 so well at 27 elevation.. 101 is above tree line at 42... 110 is at 35 elevation but it looks to be right in the middle of the biggest I have..
I live on slight slop down.. the trees down in the lower area grow pretty high. We had a tree blow over in a tropical storm a few years ago that was close to 100 feet tall! This is the "sister" tree to that one... I believe it's a white oak.. and it's canopy is beautiful! It's also the last tree to loss it's folliage.. It's proximity to the property is bad.. it's probably just 100 feet away from my dish.. BUT, the hill gains about 30 feet in elevation, and the dish is mounted(presently) about 20 feet above that.. so I've 100 feet away trying to shoot over 50 feet... that's not going to work.
I was thinking of moving this to the roof.. and moutning it on the house where the garage roof meets the house. This move me about 15 feet closer to the tree, but I'll also be much higher.. probably another 15-20 feet.... I could probably shoot around it with 110 and 119, but without going up, 101 might be in the way.. of course this has the highest orbit.
This would also be visible from the street, something the neighborhood association frowns upon, but their guidlines say that they will accept it on a house, or front yard if there is no other option for line of site. Since it's a wooded neighborhood, they actually require you to gain permission to cut down a tree above a certain diameter, but NOT to mount a dish. They value their trees... So doubt they would recommend taking the tree down as an option. Even so, the cost of doing so would far exceed the "reasonably" cost.
Since we have a cedar shake roof, DirecTV will not put it on the roof.. though the roof slope is very minor.. they say it's dangerous.. It's the back of a dormer over a garage. I have to do it myself.