From Tolkien Gateway

Well, where might be this "Land of Doom"? I only know Ambaróna, which is one of the names of the Fangorn Forest catalogued by Treebeard in LoTR II, Ch. 4: And I walk in Ambaróna, in Tauremorna, in Aldalómë,....

And this Ambaróna is (Tolkien: Unfinished Index) constructed from the Quenya words amba 'up(wards)' + róna 'east' = 'uprising, sunrise, orient', that is: East End, which is according to the Unfinished Index 'Name of Fangorn Forest in the Elder Days'. See: Reader's Companion, pp. 384-385, notes for pages 468 and 469.

I don't know if the suffix -ona really exists, neither does Fauskanger's Quettaparma mention it. --Tik 17:16, 11 November 2007 (EST)