Ohara And Tree Of Knowledge Names Encode Forbidden-Knowledge Library Erased

Status: confirmed (the name-meanings match the on-page nature of the place at its first depiction) · Technique: name-etymology

The seed

Ch. 391 — pp. 14, 19 (the Ohara flashback opens)

The flashback names both the island and its library on-page for the first time:

Ohara (オハラ) reads as the Irish surname “O’Hara” — and the island’s lead scholar Clover (= clover / shamrock) carries the matching Ireland symbol. The island-of-scholars/great-library framing also patterns on the Library of Alexandria (lost to fire) and other historical book-burnings (Qin Shi Huang’s burning of books & burying of scholars; the Mongol sack of Baghdad’s House of Wisdom).
Tree of Knowledge is captioned p. 19; its Japanese name 全知の樹 (Zenchi no Ki) is literally “Tree of Omniscience,” a direct nod to the biblical Tree of the Knowledge of Good and Evil — the tree whose forbidden fruit brings ruin on those who eat it.

(Unrecorded. Etymology documented by One Piece Wiki and the Rurubu One Piece guidebook.)

Oda repeatedly names a place for its destiny (cf. Noland Name Encodes No-Land Liar-Truth Inversion, Raftel Etymology Encodes Laugh Tale Funny Story, Elbaf Etymology Encodes Land Of Fables). Here the name-pair “Ohara” + “Tree of Knowledge” pre-loads both the scholarly-library identity (Alexandria) and the forbidden-knowledge-brings-ruin theme (the biblical tree) at the very first panel of the flashback — the reader is told what the island is and what will befall it through its names alone.
The Ireland thread (Ohara = O’Hara; Clover = shamrock; Roji = teahouse-garden roji within the broader botanical naming set) is the cosmetic layer; the Alexandria/biblical layer is the load-bearing foreshadowing.

One Piece Wiki — Ohara (trivia: O’Hara surname; Library-of-Alexandria / Qin Shi Huang / Baghdad parallels): https://onepiece.fandom.com/wiki/Ohara
One Piece Wiki — Tree of Knowledge (literal meaning “Tree of Omniscience”; biblical Tree of Knowledge of Good and Evil): https://onepiece.fandom.com/wiki/Tree_of_Knowledge
One Piece Wiki — Clou D. Clover (clover/shamrock = Ireland symbol): https://onepiece.fandom.com/wiki/Clou_D._Clover