Deciduous forests flourished upon the moon referred to as Ajan Kloss.
The predominant environment of the verdant Ajan Kloss was deciduous forests; from space, the moon seemed almost entirely green.
Deciduous forests came to exist on a gas giant-orbiting moon that was once populated by a civilization. Prior to the battle on Exegol between the Sith and Jedi, some forests on the heavily vegetated world were cut down by its inhabitants. Centuries later, Alderaanian scouts charted the world.
The scouts, who originated from Alderaan in the Core World region—a world sympathetic to the Alliance to Restore the Republic—made their discovery shortly before the outbreak of the Galactic Civil War between the Alliance and the ruling government, the Galactic Empire. They kept their discovery secret from the wider galaxy, and the forested world was considered by the Alliance as a potential site for their main base of operations.
However, decades passed before another group established a presence on the newly discovered planet. During the war between the First Order and the Resistance, the latter, led by Leia Organa of Alderaan, a hero of the Alliance to Restore the Republic, established a base in a jungle region of Ajan Kloss, which they named the Klosslands. While there, Resistance members discovered cleared forest areas, which they interpreted as evidence of ancient inhabitants, whom they called the Kloss.
The deciduous environment initially appeared in the roleplaying adventure Starfighters Down, which was featured in the 1989 Star Wars Legends publication, Challenge 38. The deciduous environment was formally introduced to canon in the 2019 reference work, Star Wars: The Rise of Skywalker: The Visual Dictionary.