The Enormous Tree when looked at is known as Ashar'Tel, according to Lavirias. It produces glowing fruit and has two shades of teal coloured leaves, The tree is located in the center of Ab'Dendriel's maze just north of where you obtain citizenship to Ab'Dendriel.
"glowing fruit" 
"teal leaves"
I wanted to include some stories about the tree as told by a NPC in Ab'Dendriel:
Player: mystic
Lavirias: I'm dedicated to delve into the deeper secrets of nature. As all seekers of knowledge, I have to dedicate much time and effort into the subject of my studies.
Player: function
Lavirias: Especially the part that Ashar'Tel plays in the workings of nature is, what I try to figure out.
Player: studies
Lavirias: Since my studies center around the nature of Ashar'Tel, there is little I can base my research on but my own discoveries.
Player: ab'dendriel
Lavirias: A city has to have a soul. I think the soul of Ab'Dendriel is Ashar'Tel. If the others would only see it that way too.
Player: Ashar'Tel
Lavirias: Ashar'Tel's fame and myth has grown with time as the tree itself has grown over time. Though everybody sees something in this tree, it's rarely the same for everyone. ... Humans travel here and look at Ashar'Tel as an avatar of their god Crunor. Dwarves probably see only firewood. ... The Elven council sees it as a valuable resource yet I see something completely different.
Player: resource/water
Lavirias: The tears of Ashar'Tel, the water of life, the blessing of the tree. It has probably more names then it has uses. ... The water that condenses as some kind of supernatural dew on Ashar'Tel's leaves is gathered and prepared by some of the eldest and wisest spellweavers of our kind.
Player: danger or dangerous
Lavirias: It was obvious that the raw waters of Ashar'Tel might be dangerous, but the fate of the forest furies has shown how dangerous and unpredictable it can be.
Player: forest furies
Lavirias: Once they were only a rebellious sisterhood, inspired by foolish amazons from Carlin they tried a rebellion on their own. In their foolish, juvenile overconfidence they stole unrefined water of Ashar'Tel. ... Assuming the elders were withholding power for themselves or something else. In the end they learned the hard way that there are things better left to those with wisdom and experience. ... Lavirias: Their careless misuse of the waters deformed their body and mind. Sadly it did not stop there. ... As if it weren't bad enough for the furies to be transformed, a tribe of orcish raiders got the rest of the stolen water into their hands and spawned a new, abominable breed of orcs, the rorcs. ... They are a halve orc, halve terrorbird variant that is erroneously called 'rorcs'.
Source of information: https://tibia.fandom.com/wiki/Enormous_Tree
TibiaQA.com is a fansite. Please note that the only official website is Tibia.com. The game Tibia and the website Tibia.com are copyrighted by CipSoft GmbH.
