Ju Kai (Forestland) [Regional Income:50] is one of the cities in the Kantou region. It had been under the control of PGG.
Notable landmarks: World Forest [Income:00,Law:00] and Giant Magnet [Income:00,Law:50]
- The name "樹界" is a homophone pun on "樹海" ("Tree-Sea", referring to an extremely broad forest), which in turn is a nickname of Aokigahara (青木ヶ原). The pun replaces the kanji for "Sea" with one of "Field/Area".
- There is a myth about Aokigahara having magnetic iron underground causing compasses to malfunction, which is the source of the "Giant Magnet" reference.