From the start, some of the phrases with describe the scenery of flora and fauna on the island sound ominous. For instance, in chapter 1, a boy
was clambering heavily among the creepers and broken trunks when a bird, a vision of red and yellow, flashed upwards with a witch-like cry ...
Creepers, broken, and witch-like are descriptive words which create an unsettling tone. In fact, the word "creeper" is used 38 times in the novel to describe the thick jungle vines, as in
I can’t hardly move with all these creeper things.
In chapter 4, too, the scenery is described in terms of a mirage:
Strange things happened at midday. The glittering sea rose up, moved apart in planes of blatant impossibility; the coral reef and the few stunted palms that clung to the more elevated parts would float up into the sky, would quiver, be plucked apart, run like raindrops on a wire or be repeated as in an odd succession of mirrors.
Words like "strange," "stunted," "plucked apart," and "odd" add to sense of the setting as eery or off-kilter. It also contains "snapping sharks," while the sun is likened to an "angry eye."
In chapter 9, the scenery continues to be ominous and oppressive. For example:
revolving masses of gas piled up the static until the air was ready to explode.
We learn, too, of a "brassy glare" and that nothing "prospered" but flies. There is a sense of foreboding in this description of setting:
Colors drained from water and trees and pink surfaces of rock, and the white and brown clouds brooded.
By the end of the novel, after the huge fire:
the island was scorched up like dead wood
There is much sense of desolation and foreboding in this setting, which reinforces the theme that evil will explode and destroy in a natural, untamed setting.