Working on the floor, I find myself filling in the holes between the branches.The lower branches are in place around the trunk. Building up from the bottom.
At one time I would've worried about all the buckling and folds, however, I know from experience that it will all quilt out...I think. Of course, if I really had some serious technique and thought ahead more, I would not have this problem. On the other hand, I wouldn't have the same piece either.
And anyway, if I knew how it was all going to work out and lay flat because I had planned carefully, I would be bored silly. So you see, my lack of method is the only way to go.