Scorched forest

The Senlin Forest is a region of large, expansive woodland. It is in the vicinity of Senlin Village, a minor farming settlement in the western Earth Kingdom. In 99 ASC, the forest suffered heavy damage from a wildfire ignited by firebenders, which caused a spirit that roamed the forest, Hei Bai, to become infuriated and attack innocent villagers. A small river flows through the woods.

History
Team Avatar briefly visited this forest during the late autumn of 99 ASC. They were flying high above it on Appa until they realized the land had been scarred by fire. Appa landed as the trio stopped to observe the damage. Upon seeing the devastation, Aang became depressed, claiming the destroyed forest was a symbol of his own failure in protecting the Earth from harm. However, Katara managed to cheer him up by saying the forest was not completely destroyed, and that the damaged portions would one day grow back and return to normal. The proof was everywhere, as scattered all along the ashes and charred trees were acorns that would one day grow to become a new forest.

Eventually, an elder from a nearby village came to see the Avatar, whom he had seen flying on Appa. He took them to his home, where he explained the crisis that had been wrecking his village. A rampant spirit was smashing buildings and kidnapping helpless villagers. The village leader pleaded to Aang for help, who agreed. The next time Hei Bai attacked, Aang attempted to calm him down, but to no avail. With his glider, he followed him back into the forest because he had kidnapped Sokka. Aang failed to rescue him, and ended up sulking in front of a bear statue after he crashed onto the ground. Hei Bai and Sokka had mysteriously vanished from sight.

Aang walked back to the village and admitted to Katara he couldn't save Sokka, but was perplexed to see her ignore him. Soon Aang realized that he was in the Spirit World, completely trapped and inable of communicating with others. When he saw Fang the dragon approaching him, Aang tried to fly away on his glider using airbending, but quickly realized his bending abilities were blocked. With no chance of escape, Aang waited for the dragon to come, whence he understood he had come to help, not attack. Fang took him away.

Not long after, Aang returned to the forest and left the Spirit World. Fang left him in the same place through which he entered the Spirit World - the bear statue. Aang, now knowing what to do, faced Hei Bai at the village for the last time. He did not fight him. Instead, Aang spoke to the spirit and managed to understand why he was angry; the forest was once its home, but was now ruined because of the wildfire. Aang told Hei Bai the damage was not permanent and gave him an acorn, a symbol of rebirth, renewal, and life. Hei Bai calmed down, transformed into a panda, and left for the woods. He released all the humans he had abducted, including Sokka, who came walking out of the forest alongside many others.