The Integral Trees
|The Integral Trees|
Cover of first edition (hardcover)
|Genre(s)||Science fiction novel|
|Media type||Print (Hardback & Paperback)|
|Dewey Decimal||813/.54 19|
|LC Classification||PS3564.I9 I54 1984|
|Preceded by||A World Out of Time|
|Followed by||The Smoke Ring|
The Integral Trees is a 1984 science fiction novel by Larry Niven (first published as a serial in Analog in 1983). Like much of Niven's work, the story is heavily influenced by the setting: a gas torus, a ring of air around a neutron star. Its sequel is The Smoke Ring.
The story is set at the fictional neutron star Levoy's Star (abbreviated "Voy"). The gas giant Goldblatt's World (abbreviated "Gold") orbits this star just outside its Roche limit. Thus, Gold's gravity is insufficient to hold its atmosphere, which is pulled loose into an independent orbit around Voy. This orbiting air forms a ring known as the Gas Torus. The Gas Torus is huge—one million kilometers thick—but most of it is too thin to be habitable. The central part of the Gas Torus, where the air is thicker, is known as the Smoke Ring. The Smoke Ring supports a wide variety of life.
There is no "ground" in the Smoke Ring; it is a world consisting entirely of sky. Thus, most animals can fly, even the fish. Furthermore, since the Smoke Ring is in orbit, it is in free fall. There is no "up" or "down". Most animals have trilateral symmetry, allowing them to see in all directions.
Most plants in the Smoke Ring are quite fragile, as they do not have to support their own weight. A notable exception to this rule are the eponymous Integral Trees. These are trees that are up to 100 kilometers long. Tidal locking causes them to be oriented radially, with one end pointing in toward Voy and one end pointing out. The ends of the tree feel a tidal force of up to 1/5 g. Each end consists of a leafy "tuft", which is where photosynthesis occurs. Compared to trees on Earth, the tufts are both canopy and roots.
Each tuft of a tree is up to 50 kilometers from the tree's center of mass. Thus, a tuft is either orbiting too slowly (the "in" tuft) or too quickly (the "out" tuft), compared to the atmosphere, which is in orbit at all points. The ends of the tree are subject to a constant hurricane-force wind. This wind bends the ends into the shape of an integral symbol: ∫. The trees are "fed" by the constant inflow of materials to their tufts caused by water and food being blown into the tufts, or alternately onto the trunk, where the gravity-like tidal forces pull the material out towards the tufts.
The Smoke Ring was colonized 500 years prior to the beginning of the story by a crew of 20 astronauts on board an interstellar "ramship". Their descendants have adapted to the free-fall environment by growing taller and developing prehensile toes. Small numbers of devices from the original crew are coveted items in the Smoke Ring society.
Plot summary 
Plot setup 
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.
Plot conflict 
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.
Plot resolution 
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.
Awards and nominations 
The Integral Trees won the 1985 Locus Award for Science Fiction novel
The Integral Trees was a nominee for the following awards
- 1985 Hugo Award for Best Novel
- 1985 Nebula Award for Best Novel
- 1985 Science Fiction Chronicle Reader Awards
- "The Locus Index to SF Awards: 1985 Locus Awards". Retrieved 2008-05-15.
- "The Locus Index to SF Awards: 1985 Science Fiction Chronicle Reader Awards". Retrieved 2008-05-15.