So here's how to do it with pictures to help along the way.
First cut strips of fabric for the outer rings of the flower/tree. I cut 1.25" strips since I was using some leftover charm squares and that's an easy size to work with.
Take a strip from your pile and pick a side of your shape to add it to and line up the edges. Sew 1/4" seam.
Grab the next strip and line it up with the next edge of the center shape (I go clockwise around) and trim the tail of the first strip.
If you look closely, you can see I already sewed that last seam before I trimmed. I prefer to do it before because it makes the seams easier to keep straight, but you can do it either way.
Keep adding strips around the center. When you get to last strip, it looks a little crazy and tricky to figure out where to trim:
After going all the way around the center, press with an iron.
The next step is where I think the fun comes in. In the tree block, you'll notice that ByNeedleandThread kept all of her logs parallel to each other. In the flowers that I did, I liked to rotate the logs a little bit so they had a little more movement to them. Trim your flower how you want it to look for the next round. I haven't done enough of these to have a good sense about what's going to look best, but they seem really forgiving.
Go around your flower just like the first time. I purposely started on a different side than the first time so that the shortest and longest edges are always in the same place. Here's what mine looked like after the second time around.
Two rings of strips looked like it would be enough, so I attached this whole thing to fusible web and trimmed it to a flower looking shape.
When you applique this on, you'll want to make sure to sew around the edge (either with a straight stitch or with zig zag). Because of the seams, not all the fabric is attached to the fusible web. This probably makes more sense once you do it.
I hope this is helpful and if you have questions or are having trouble, I'd be happy to help! Have fun!!