Revered Terebinth
I doubt it. The sylvari there say it was at first a normal tree, which was magically altered when a sylvari died there. The pale tree came from its own seed, and is presumably its own species. Also, I’m fairly sure the first fruit the pale tree bore was the sylvari.
This tree is actually far more similar to the Ancestor Trees of Elonian centaur tribes. The sylvari died in a unique way and became a sort of magical fertilizer, not the tree itself.
Stop treating GW2 as a single story. Each Season and expansion should be their own story.
Yeah, for it to be the birth of another pale tree, there would likely be many more out and about. Rhiannoc also died a heroic death fighting off hordes of Undead in Lychmere swamp, but his grave shows no signs of a special tree. I would also like to point out that he was the first Sylvari to die (I specifically remember Caithe mentioning feeling a shudder go out through the dream at his passing), so he has had more time to grow his “tree” than Revered Trebinth.
A lot of people jump on any semi-magical sylvari plant as “another Pale Tree”, but we have no evidence of anything like that, and the sylvari have a lot of magical plants that they tend around the place. Even in Guild Wars 1 days (long before the Pale Tree was even planted) the Maguuma Jungle had a lot of magical and semi-sentient plantlife. I think in this case the simple answer is much more likely.