The Forest is a sector of Lyoko, and is arguably the most beautiful. It is mostly a complex series of paths intertwining between thousands of trees. Large open areas do not occur like those in the Desert and Ice Barrier Sectors. It also has a lot of hollow tree trunks which connects areas of the Forest and has often saved the lives of our heroes. Despite the fact that paths are narrow in this sector, XANA often sends his largest monsters, such as Megatanks and Crabs, to attack our heroes when they are trying to deactivate a Tower there. It is also the only sector in which XANA directly attacked towers, once in Code: Earth and again in Contact. The appearance of the sector changed noticeably from Season 1 to Season 2. In Season 2, the sector had a "morning look" (the lighting) and the paths were more detailed (see image to left). In Season 1, the path was a dull green and there were far less trees. The lighting was also taken out. In Lyoko Minus One, XANA possessed Aelita and destroyed the Forest.
The forest was recreated between the episodes William Returns and Double Take by Jeremie and Aelita. It made its first reappearance in Opening Act and the new forest appears to have new areas added on such as the forest arena seen in Opening Act.
- The first Replika shown in the episode Replika, contains a recreation of the Forest sector.
- This is the Sector where the first Tower activated by Franz Hopper was seen.
- Like the Ice Barrier, the forest has simulated water which one could possibly swim in. Yumi once skimmed it on her Overwing in Temptation.
- This was the only outer sector to only make one appearance in season 3 in Lyoko Minus One
- The last sector in which the Scyphozoa was seen physically.