Malyck and Kralkatorrik
I do hate to be the killjoy here, but we actually see that tree (right on that page, in fact), and it looks nothing like a Pale Tree- or a blighting tree, for that matter. Nor has it grown nearly as fast. It does, however, look like a somewhat bigger specimen of a species of tree we see all over Kourna- Mebahya trees, if that link you provided is to be believed.
As for Malyck- what we hear from him is that his tree is at the end of the river his pod ended up in. While it is a little unclear where exactly that is, it seems most reasonable for it to be somewhere west, or south, of Brisban, and practically impossible for it to be in Kourna.
Isn’t there an ancestor tree in Dry Top?
No, but the centaurs do have their village centered around a tree.
Stop treating GW2 as a single story. Each Season and expansion should be their own story.