Home of the Fallen Star, the Great Tree was a place of worship for the goblins of records/Try bel long ago. Under the roots of the tree was an ancient temple. There was a mosaic room that depicted the arrival of the Power Gem, the ceremonial worship of the goblins, followed by the growth of the Great Tree.
Elsewhere, there was evidence of outsiders who experimented on the Power Gem. Their malpractice caused the plagued vines to take root from within the Great Tree and cause damage for year to come. The party slew a ferocious Treant empowered by the Power Gem.