The Integral Trees
Larry Niven
 Quinn Tribe inhabits the "in tuft" of Dalton-Quinn tree. They normally subsist on the tree's cottony foliage, augmented by hunting and a flock of domesticated turkeys. But ever since the tree passed near Gold six earth years ago it has been falling in toward Voy, nearly dropping out of the Smoke Ring. As a result, the tribe is suffering from a severe drought. The tribe's leader, the Chairman, decides to send a party of nine up the tree, ostensibly to hunt and re-cut tribal markings into the trunk. The group consists mostly of cripples or people the Chairman dislikes, and including the Chairman's son-in-law (and rival), Clave, and Jeffer, the Scientist's apprentice. As they approach the midpoint they notice that the tribal markings are different. When the party reaches the midpoint of the tree, they are attacked by members of the Dalton-Quinn tribe living at the other end of the tree. During the battle a massive tremor splits the tree in half, causing the in tuft to fall farther in toward Voy (killing its inhabitants) allowing the out tuft to find a new equilibrium closer to the Smoke Ring's median. The seven surviving members of the Quinn Tribe and one of the attackers jump clear of the shattered tree, and are left adrift in the sky with only a few "jet pods" (high pressure seed cases that provide a temporary thrust when opened) as their only method of propulsion. Before dying of thirst, they manage to hook a passing "moby" (a flying whale-like creature), which takes them to a "jungle", a floating mass of plant life. They cut loose and crash, and find themselves in the middle of a battle between the Carther States, who live in the jungle, and slave-runners from London Tree. The group is split when six of them are captured by the slavers; the other two remain in the jungle. Carther States counter-attacks some weeks later, and the Quinn Tribe group is reunited. During the battle they manage to steal the London Tree's CARM (Cargo And Repair Module), a miniature spacecraft, a relic of the original settlers. Not fully understanding how to pilot the CARM, they engage its main motor, which sends them thousands of miles away before running out of fuel. As a result, they become the first Smoke Ring inhabitants in centuries to see the naked stars. Unknown to any of the inhabitants of the Smoke Ring, the ship their ancestors arrived in, Discipline, is still in orbit, and its AI autopilot, Kendy, is watching their progress. When Kendy sees the CARM dangerously far from the habitable area of the Ring he contacts them. With help from the on-board computer and after some interaction with Kendy, the occupants of the CARM eventually find their way safely back into the Smoke Ring. Unable to find their way back to any of the trees they know, they decide to settle on a new tree, which they dub Citizens Tree.