They're the world's tallest flowering trees - giant 25 story goliaths that watch over one of Australia's most beautiful forests.

But according to a new book, the Mountain Ash trees of the Victorian Central Highlands are hiding in plain sight, with many Australians unaware of the natural wonder just an hour and a half from the MCG.

Professor David Lindenmayer spoke to ABC Radio Nation about his new book 'The Great Forest'.

Listen to the interview here.