It's hard to tell from your photo about the trees (since you took it not in the plane of the with the dish/feedhorn/satellite alignment, plus how far away the trees are).
dishpointer website is pretty good for finding out about distant obstacle clearances (i.e. if a neighbor's tree is in the way of a satellite from your dish site).
trees do make a difference - a neighbor's tree blocks some of my c-band dish from AMC-6 so several signals are not as strong in the summer as they are in the winter. I'm hoping the neighbor will trim the tree this winter like they usually do when the tree gets unwieldy and then I should have AMC-6 strong yearround until it grows out again.