Just for fun, I changed the image size to 8000x8000, and it did produce a pretty tree.
So my next question would be about the font size of the node descriptions. Is it a fixed font size, or is it changeable?
If I could reduce the font size to 8 or 9, the tree should still be readable, but I could reduce the image size (because 8000x8000 is not feasible for a web page)
Any comments are appreciated!