The narrator uses the word "scar" repeatedly early in the novel to describe the damage done when the plane carrying the boys crashes on the island. One quote is as follows:

Beyond falls and cliffs there was a gash visible in the trees; there were the splintered trunks and then the drag, leaving only a fringe of palm between the scar and the sea.

The "gash" and the "splintered trunks" of trees are caused by the crash-landing of the plane on the island. As will much later be implied, the plane's pilot, thinking he would die in the crash, tried to parachute out, only to die when his parachute got tangled in the trees.

Meanwhile, it appears that the plane landed safely enough so that the boys survived. They seem to have passed out briefly from the impact, now to be awoken and assessing what has happened.

Calling the gash made by their arrival a "scar" symbolizes the damage their intrusion on the island has done to this natural, uninhabited paradise. It is not a pleasant image. It implies the boys do not belong, that from the start their presence is doing harm.

In the quote above, there is only a thin line between the scar caused by their arrival and the sea. This thin line symbolizes the thin defense of civilization they bring with them to the island. Outside of this thin band of possibility, they are faced with the overwhelming force of nature: either the dangerous jungle beyond the crashed plane or the ocean.

The scar also symbolizes and foreshadows the way this violent and unwanted encounter with nature will psychologically scar the boys. It also foreshadows the large fire that will consume the island near the end of the novel.

A scar generally refers to a mark, blemish or indentation left on the skin or an object after it has been damaged. In the case of the island in Lord of the Flies, it refers to the mark left by the planes' fuselage when it crashes after being shot down. It is later washed away by the sea.

The first reference to the scar is found at the beginning of chapter one when Ralph is introduced as "the boy with fair hair":

All round him the long scar smashed into the jungle was a bath of heat.

The scar is quite extensive, and the word "smashed" indicates a violent encounter that caused damage. The story is set during a war, and the boys have been evacuated when their plane is damaged. The pilots are killed and the plane crashes onto the island. Most of the boys (as far as we can ascertain) survive. Ralph appears to be quite pleased, and when Piggy sees him he is standing on his head.

In the middle of the scar he stood on his head and grinned at the reversed fat boy.

When the two start speaking Piggy attempts to explain what has happened and provides a brief explanation of the crash and how they came to be there:

He looked up and down the scar.
“And this is what the cabin done.”

Golding's numerous references to the scar emphasize its significance. The scar is symbolic of a disruption in nature. The peaceful, calm and probably pristine nature of the island has been damaged by the sudden and violent arrival of humans. It suggests that man's intervention causes harm.   

The presence of a scar also suggests that the damage is permanent.The scar will never disappear and will become an indelible indication of the harm that was done. Although the forest and plants will heal, there will always be evidence of what happened.

Furthermore, the scar foreshadows further disruption and destruction. The boys, for example, destroy a large section of the forest when their first signal fire goes out of control. At the end of the novel, a fire rages on the island and, ironically, becomes a signal for rescue. The boys are saved from their own destruction and that of the island. Other examples of destruction to come are the bloodthirsty hunts conducted by Jack and his hunters; the boys' general loss of civilized behavior; the adoption of savagery; and, eventually, the deaths of Simon and Piggy.  

You are probably having a difficult time finding a quote because the scar is not related to the boys destroying the island.  The scar is the path of burned island made by the plane as it went down and the storm dragged it into the ocean.  The boys destroy the island by fire.  The two ideas are somewhat related because the destruction on the island is caused by humans--both human error and malice. 

The scar made by the plane is a constant reminder of why the boys are on the island.  They were being moved to safety, away from the world war that made where they lived unsafe--most likely the German bombing of London during World War 2.  The scar ties the violence that occurs on the island to that of the world as a whole.  The boys' inability to get along on the island reflects the adults' inability to get along as well. 

The first reference to the scar is as follows:

"When we was coming down I looked through one of them windows.  I saw the other part of the plane.  There were flames coming out of it.""

He looked up and down the scar.

"And this is what the cabin done." 

What does the scar symbolize in Lord of the Flies?

In the first chapter of Lord of the Flies, a severely damaged swath of the island is described several times as a “scar.” This damage to the otherwise pristine island along with the plane crash that caused it symbolize the negative ways that modern civilization affects the natural environment. The scar also represents the severe harm that war inflicts, not only on nature but also on society’s normal functions.

As the novel opens, “the fair-haired boy” later identified as Ralph is the first boy to emerge from the jungle after the plane crashes on a remote island. The novel’s narrator describes this area a “long scar smashed into the jungle.” He hears the voice of another boy, later identified as Piggy, who then emerges and joins him. While they try to figure out exactly what happened, they examine this “scar,” a wide swath where the trees had been broken off.

Piggy “looked up and down the scar,” while Ralph “touched the jagged end of a trunk.” Piggy comments that the plane’s cabin had inflicted the damage, then continued out into the ocean. He had apparently seen the plane burning and cutting through the tree trunks. They continue toward the beach, crossing a green area where many palm trees remain standing, but the fallen trees have caused an upheaval and the grass is everywhere.”

From the shore, the boys gaze out into the water, where a coral reef separates the tranquil lagoon from the open sea. This vista offers a stark contrast to the forested but damaged land. As they continue getting to know each other, they make their way to the granite platform, an elevated and undisturbed stretch of land.

The boys’ conversation and the descriptions of the landscape show the scar as a physical injury to the natural world of the otherwise idyllic island. As the book progresses, the scar is also revealed as an apt metaphor for the damage to the social world, which the boys cannot reconstruct on their own. The rules and norms of social interaction are left broken and jagged like the trees.

In William Golding's Lord of the Flies, what is the significance of the scar?  

William Golding's novel Lord of the Flies is quite symbolic, so anything which plays a significant role in the novel also has a significant symbolism to be examined. The answer above, given by tropicof, is excellent; I would only add several other considerations.

The first description of the jungle which Golding gives us is the image of the scar: "All round him the long scar smashed into the jungle was a bath of heat." Despite the lush beauty of this tropical setting, it is the scar which Golding immediately highlights, setting the tone for the rest of the novel.

The three boys who explore the mountain (Ralph, Jack, and Simon) can clearly see the scar from above; throughout the novel, these three characters are the most aware that something is wrong on this island. Ralph has trouble articulating the evil he senses, but he knows it exists, like the scar. Simon, too, recognizes the evil and is able to identify it as themselves; however, no one listens to him. Jack is less obviously aware that things are not right on the island (probably because he is the primary cause of the evil), but he has just been shocked that he was not elected chief (something which was a given in his mind), so he is wounded and aggressive.

The scar is also a symbol of what happens when something beautiful is destroyed, and other examples of that can be found throughout the novel: the innocent little boy with the mulberry birthmark who died in the initial fire, the sensitive Simon who only wanted to share his revelation with everyone, the intelligent boy (Piggy) who was ignored and tormented because of physical attributes, some of which were beyond his control.

The other children will go on to live their lives but will always carry the scars of this experience.

In William Golding's Lord of the Flies, what is the significance of the scar?  

The scar is essentially a simple way for the storyteller to explain why the boys are stranded on this island. The plane that was carrying all of them had to make a crash landing on the nearest bit of dry land. Since the island is heavily covered with trees and shrubbery, the plane tore a long gash through all the vegetation. However, the pilot was successful in landing safely enough so that none of the boys were killed. The pilot himself bailed out at the last moment and was killed. The "scar" takes on symbolic meaning for the marooned boys, as do many other things on the island.

In William Golding's Lord of the Flies, what is the significance of the scar?  

On a literal level, the "scar" is the mark left by the conveyance that brought the boys to the island.  It crash-landed in a skid, knocking down trees and brush leaving a mark or "scar".  On a figurative level, the scar represents the evil that mankind has wrought on the world in Golding's view.  Golding wanted to say to  the readers that the evil within mankind has left an ugly, permanent mark on the world.

What is the significance of the scar in Lord of the Flies?

The boys find themselves surrounded by natural beauty on the island:

This was filled with a blue flower ... and hung down the vent and spilled lavishly among the canopy of the forest. The air was thick with butterflies, lifting, fluttering, settling ... clambering among the pink rocks, with the sea on either side, and the crystal heights of air, they had known by some instinct that the sea lay on every side.

This world exists as a paradise until the boys' arrival: and with them comes destruction. They deplete the natural resources, set fire to the beauty of the island, make brutal sport out of murdering the animals, and then resort to murdering each other.

Near this same description of the island in chapter 1, Ralph turns to the boys and proclaims: "This belongs to us." With this, he must claim the "scar" they create even from the beginning:

Beyond falls and cliffs there was a gash visible in the trees; there were the splintered trunks and then the drag, leaving only a fringe of palm between the scar and the sea.

The scar is an area which has been devastated by the plane's crash—the wreckage ripping through trees and natural beauty to destroy the paradise in that spot.

The scar then symbolizes the power of mankind to devastate the delicate and beautiful balances in nature. Sometimes, this is done through technological progress, as seen in the plane. But sometimes this is seen through mankind's quest to exert power over nature itself, as seen in the murder of the pig. Either way, nature suffers because of mankind's presence.

While Ralph's initial claims to the island project mankind's quest to rule over nature, he is also claiming the scar, and therefore the devastation, that mankind creates.

What is the significance of the scar in Lord of the Flies?

The scare refers to the area on the island where the plane crash decimated the natural landscape. The name of the scar is both indicative of its physical appearance, as the upturned ground and smoldered foliage resembles a wound on otherwise tropical paradise, and the symbolic meaning of mankind being a scar on the tranquility of the island by bringing about violence and hatred.

The scar is also symbolic of the psychic wound that the boys have suffered by being left alone with no authority at such an early age. While at first, they feel as though they have stumbled on to paradise, it is clear that they require an established order and that the freedom for which they are not prepared has traumatized them.

What is the significance of the scar in Lord of the Flies?

The scar represents the damage that humankind regularly does to the natural world. The plane crash is one such example, and the boys's occupation of the island is another. When the boys first crash-land on the island, they think it's some kind of demi-paradise. And they're absolutely right; but that's only because neither they, nor any other human beings, have been living there. Mother Nature was doing just fine before these entitled young hooligans showed up and proceeded to trash the place.

The physical scar left behind by the plane crash will take a long time to heal, just like the psychological scars inflicted on the boys by their descent into outright savagery. But in both cases, the recovery process, however long it takes, will start the very moment the surviving boys step off the island for what one hopes will be the last time.

What is the significance of the scar in Lord of the Flies?

The scar is actually the place where the plane ripped across the island as it was crashing. Symbolically, it represents the injuries suffered by the island as a result of human habitation. When the boys arrive, the island is an idyllic tropical paradise. The wreak havoc on the environment by eating all the fruit, using the land as a public toilet, and mercilessly killing pigs and other small animals they want to use in their games. By the time they are ready to leave, the island is on fire and almost totally destroyed. The rather small scar of the airplane has turned into a giant, gaping wound that the boys have inflicted what was a paradise. This reinforces Golding's theme that man has an evil nature that must be controlled or man will destroy both himself and his environment.