Boin Archipelago

The Boin Archipelago (ボーイン列島, Bōin Rettō, called the Bowin Islands in the Viz Manga and FUNimation subs) is a series of flower shaped islands in the Grand Line. Within them are various gigantic bugs and vicious man eating plants. Usopp landed on one of these islands after being sent flying away by Bartholomew Kuma.

In that island, the swindling forest of Greenstone (グリンストン, Gurinsuton, called Glinston in the FUNimation subs). Also, as of recent chapters, it is known to have a forest made of food, called the Forest of Gluttony, that includes a river of noodles surrounded by Plum Trees and Corn Stalks.

Although, its mentioned there are thieves in Greenstone, the only known resident so far is Heracles.

According to the anime, the islands are giant meat eating plants that eat overweight animals that are in the greenstone forest.