"Cats are intended to teach us that not everything in nature has a purpose.”
Garrison Keillor

You will find something more in woods than in books. Trees and stones will teach you that which you can never learn from masters. 
Saint Bernard

Nature is a revelation of God; Art a revelation of man.
Henry Wadsworth Longfellow

As if our birth had at first sundered things, and we had been thrust up through into nature like a wedge, and not until the wound heals and the scar disappears, do we begin to discover where we are, and that nature is one and continuous everywhere.
Henry David Thoreau

A man who lives with nature is used to violence and is companionable with death. There is more violence in an English hedgerow than in the meanest streets of a great city.
P.D. James

"If trees could scream, would we be so cavalier about cutting them down? We might, if they screamed all the time, for no good reason."
Jack Handey 

"In every walk with nature, one receives far more than he seeks." 
Anonymous 

"There is pleasure in the pathless woods, / there is rapture in the lonely shore, / there is society where none intrudes, / by the deep sea, and music in its roar; / I love not man the less, but nature more."
Lord Byron

Look deep into nature, and then you will understand everything better.
Albert Einstein

Every flower is a soul blossoming in nature.
Gerard De Nerval

Nature always wears the colors of the spirit.
Ralph Waldo Emerson

In all things of nature there is something of the marvelous.
Aristotle

Come forth into the light of things, let nature be your teacher.
William Wordsworth