Writers often use nature in their works to construct or convey meaning.How such use is important to establish the themes?
To add to the ample explication provided above, certain authors have incorporated Nature into their works as key elements of the particular literary movement and philosophy to which they adhere. For example, in Frankenstein, the Romanticist Mary Shelley includes particular passages describing the magnificent Mount Blanc of France in the Alps, as well as other natural phenomenon and beauty such as the lakes, areas in which Victor Frankenstein finds solace from his troubling psyche and soul, even experiencing the sublime. The natural world is, of course, the antithesis of the corruption of nature created in the scientific world, Victor's creature.
That nature provides an elevated state of the spirit is no more beautifully portrayed than in William Wordsworth's "Lines Composed a Few Miles Above Tintern Abbey" in which the poet returns to a place visited as a youth where he experiences this "sublime": The mind loses consciousness and the spirit is able to experience beyond rational thought, and the burden of the worldly is lifted as the spirit connects with Nature:
....And I have felt
A presence that disturbs me with the joy
Of elevated thoughts; a sense sublime
Of something far more deeply interfused,
Whose dwelling is the light of setting suns,
And the round ocean and the living air,
And the blue sky, and in the mind of man;
A motion and a spirit, that impels
All thinking things, all objects of all thought,
And rolls through all things
Likewise, the Transcendentalists felt joy and union with nature. Ralph Waldo Emerson felt that everything in the world is a reflection of the Divine Soul, and the physical facts of the natural world are a doorway to the spiritual world. God's spirit is revealed in nature. Emerson writes in Nature:
In the presence of nature, a wild delight runs through the man, in spite of real sorrows. Nature says--he is my creature, and augre [in spite of] all his impertinent grief, he shall be glad with me.
On the other hand, the Dark Romantics such as Edgar Allan Poe as Herman Melville perceived Nature as a formidable force, if not reflective of the dark side of man. In Poe's "The Fall of the House of Usher," the crumbling house and decay of the natural growth outside parallels the decay of the Usher family. In his magnum opus Melville's Ahab perceives Nature in the great white whale as some inscrutable metaphysical force:
All visible objects...are but as pasteboard masks. But in each event--in the living act, the undoubted deed--there, some unknown but still reasoning thing puts forth the moldings of its features from behind the unreasoning mask. If man will strike, strike through the mask!
Jack London, previously alluded to, a follower of Naturalism, as was Stephen Crane, write, not of a Nature that sympathetic to man's inner being and an inspiration, but rather an indifferent, if not at times hostile, universe in which man is at its mercy. The unnamed man in "To Build a Fire" is ill-equipped to deal with the merciless Yukon. Similarly, the shipwrecked men in "The Open Boat" are at the mercy of an uncaring universe,
A singular disadvantage of the sea lies in the fact that after successfully surmounting one wave you discover that there is another behind it just as important and just as nervously anxious to do something effective in the way of swamping the boat.
The theme of the absurdity of man's attempt to formulate an interpretation of Nature is certainly in this story in which God is absent from Nature and it is unromantic and uncaring is exemplified in the resolution when the best swimmer and sailor in the boat washes up on shore after having drowned. For the Naturalists, Nature is lacking in sentiment.
In addition to Nature as thematic of itself, it is often used as symbol. Mark Twain's river of The Adventures of Huckleberry Finn is certainly symbolic of a setting in which man can be free of the restrictions imposed by society. For, on the raft, Huck and Jim can be friends, whereas in society, they must be slave and master and even hide lest Jim be caught and punished for escaping.
Sometimes Nature symbolizes life itself, as it does in Hemingway's novella, The Old Man and the Sea in which all is stripped away from the narrative but the human struggle to survive, and above all, to dream.
Certain stories, Jack London’s Call of the Wild, Mark Twain’s The Adventures of Huckleberry Finn, Henry Lawson’s short story “The Drover’s Wife,” and many others used nature to convey meaning in addition to establishing setting. Lawson’s story of a desperately poor wife and mother left alone in the vastness of the Australian outback with her four young children while her husband is away uses nature to establish a sense of despair and isolation. Nature, particularly as discussed by the likes of a Henry David Thoreau in his classic Walden (a work of nonfiction, of course), can provide a tranquil and aesthetically beautiful environment that nurtures the soul. Sebastian Junger, in his nonfiction depiction of the final days of the crew of a fishing boat, the Andrea Gail, The Perfect Storm, nature is used to both depict the tranquility and beauty inherent in a life at sea and to expose the reader to the terrible dimensions of nature in turmoil, in this case, the massive and deadly storm that provided Junger’s book its main conflict. “The Drover’s Wife” takes the perspective of nature as an exceedingly dull, potentially deadly adversary. Early in his story, Lawson describes the setting as follows:
“Bush all around - bush with no horizon, for the country is flat. No ranges in the distance. The bush consists of stunted, rotten native apple-trees. No undergrowth. Nothing to relieve the eye save the darker green of a few she-oaks which are sighing above the narrow, almost waterless creek. Nineteen miles to the nearest sign of civilisation - a shanty on the main road.”
Twain, in The Adventures of Huckleberry Finn, uses nature, in particular, the Mississippi River, as the main constant through which his story metaphorically and literally flows. The Mississippi River, in Twain’s story, assumes a role as important as that of the characters. Early on, Huck refers to the waterway as “the river, a whole mile broad, and awful still and grand.” The Mississippi serves as a means of transportation while providing the characters, Huck and Jim, the entry into other worlds. Most importantly, the river provides Huck a sense of security removed from the living creatures that could threaten his and Jim’s survival. As Huck related following yet another potential misadventure: “I never felt easy till the raft was two mile below there and out in the middle of the Mississippi.”
Jack London, in Call of the Wild, used nature in as profound a manner as any author. His story of a dog, Buck, transported against its will from the “sun-kissed Santa Clara Valley” to the frozen tundra of Alaska and a life of hardship uses nature to contrast the transition to which Buck is subjected, as in the following passage:
“It was a hard day’s run, up the Cañon, through Sheep Camp, past the Scales and the timber line, across glaciers and snowdrifts hundreds of feet deep, and over the great Chilcoot Divide, which stands between the salt water and the fresh and guards forbiddingly the sad and lonely North.”
As London’s protagonist, the dog Buck, gradually learns to adapt to his new if uninviting surroundings, the author again uses nature to convey a sense of isolation and abandonment:
“The first theft marked Buck as fit to survive in the hostile Northland environment. It marked his adaptability, his capacity to adjust himself to changing conditions, the lack of which would have meant swift and terrible death. It marked, further, the decay or going to pieces of his moral nature, a vain thing and a handicap in the ruthless struggle for existence.”
Finally, London employs nature to again convey an atmosphere of danger and impending doom, referring to the challenges confronting Buck:
“He must master or be mastered; while to show mercy was a weakness. Mercy did not exist in the primordial life. It was misunderstood for fear, and such misunderstandings made for death. Kill or be killed, eat or be eaten, was the law; and this mandate, down out of the depths of Time, he obeyed.”
Nature consists of more than trees and bushes; it includes wild animals, weather, disease, and all matter of dangers and opportunities. It has consequently provided authors an unlimited environment in which to tell their stories.
There is a book I read for English called How to Read Literature Like a Professor by Thomas C. Foster and it has a chapter about why authors use nature in literature. It mainly focused on weather, but it said that the weather or season in a story can be a symbol for something deeper. For example rain can represent things like sadness and pain, but can also represent regrowth like with "spring showers bringing may flowers".