The logo design is not obvious to most people, although some notice the shape of the hoof print and thorn.
I have learned to identify buckthorn by its buds in winter, and the shape reveals the supposed origin of its common name. Often, but not all of the buds on the tips of side branches will show this shape: the hoof print of a deer with a thorn in between, hence "buckthorn".
Whether this origin of the common name is true or not may never be confirmed, but it makes sense. I decided to elongate the thorn (it usually does not exceed the length of the buds by much) to become a strike-through of the word buckthorn, enforcing the intention of the invasive plant's removal.
The scientific name, Rhamnus cathartica, implies the thorn at the end of each twig, and catharsis - cleansing of the body, in this case through diarrhea. No wonder the birds spread it so easily!