When I look at the leafy trees in my back yard, from several yards away, I can’t see the stems of the leaves. Some of them do seem to be floating in the air. I made a point of looking, after reading similar comments on this board. Granted, I can see larger branches, which do seem to be missing on the drawings in this strip.
However, the depiction of trees in other strips is “unrealistic” in other ways — they are usually just shown as a blotch of green with a brownish trunk (when the artist bothers to include a background at all). If you were to just accept it as an artistic style, and let it go, it wouldn’t bother you any more.