This is Zanthoxylum clava-hercules in that it has such knobs on the bark and such big trunks

Fine by me! The botanical garden often has plants mislabeled. I rely on others to correct them. Thanks!

I moved it to the correct entry.

Both species are are called Toothache Tree, easy for confusion. I get some miss-labels at gardens myself. Neither species is really common all over the place and most people don't know of them.