I'm assuming you mean this quilt:
It seems to be a variant of the log cabin block, with crazy-quilt style. Very cute!
Looking at image zoomed way in, I can see that there is a red square at the top of the trunk of the tree. That square is equivalent to center block of a log cabin block. Logs are steadily added to center square, but on only two sides of the square. (A regular log cabin block puts logs on all four sides of the center square.)
What makes this one particularly charming is that there is irregularity in lengths and widths of the strip, rather than building perfectly regular triangle shape. Plus all the fun embroidery and embellishment with various types of trim. The irregularity starts pretty very early. The first two logs (first one of the left, then one on the right) are the same width, and come out to the expected lengths, but after that the next two logs on the left have the same amount of protrusion.
I don't see any seams in the background even when I zoom way in, so I expect that the background material was used as a foundation while constructing the tree. I guess that the truck was sewn on first, then the red square and then all the logs, steadily working upwards the top.