5.1 Naturalism
There are many and complex explanations of what does really happen to us when we become truly 'engaged' by a work of art, but most of them seem to suggest that what takes place is a complex interaction of the mental and the physical.  It is almost as if the artist enabled us to explore our own senses in a detached way, and then persuaded us to carry the exploration forward from the purely physical level to something far more all- embracing and therefore more satisfying.
Nature in art first and foremost encapsulates the natural features which have not changed much over the centuries and for the most part, they are works of enjoyment in which the artist singles out the particular pleasures that give them their greatest joy.  In the poems of Milton it was the brightness of a Spring morning; for William Cowper it was the sight of 'animals running free'; for Coleridge it was the exhilaration of climbing a mountain. Emily Bronte so loved her wild and windswept Yorkshire moors that she makes you feel that you are walking with her over them. These experiences sink deep into the memory, never to be forgotten: as Robert Louis Stevenson lay dying in Samoa he pined to see again the hills of home in Scotland and feel the winds 'austere and true'.
The  tradition of pastoral poetry,which started with Edmund Spenser's Shephearde's Calendar in  1579, celebrated a rustic ideal, where people 'hating the tradeful citys hum' fled from the insinuating corruption of the courtly life to find peace, harmony and the pleasure of simple things, and where a contented peasantry went about their ways w'th a bucolic jollity. 
Then, the way of looking at the countryside changed. In 1770 William Gilpin published his Observations on the River Wye and several parts of South Wales in which he set about 'not barely examining the face of a country, but examining it by the rules of picturesque beauty'. Two years later there followed his guide to the picturesque scenery of The Mountains and Lakes of Cumberland and Westmorland and in 1777 Paul Sandby published his engravings, A Collection of Landscapes, from which people south of the border could appreciate the grandeur and isolated beauty of the Highlands of Scotland. The Romantic movement had been born: henceforth the appeal of natural beauty was to lie in rugged mountains shrouded in clouds, windswept moors, shadows, caves, darkness, moonlight, dawn and twilight. With the publication of the Lyrical Ballads in 1798 Wordsworth and Coleridge established a new and different way of describing the beauty of nature and the landscape, and the effect they could have upon the human spirit.
However, it is not just the grandeur of majestic scenery or the wildest elements that can stir the spirit. It is often in those Secret and Special Places that a poet will find the greatest contentment. For Coleridge it was his Lime-tree bower. For Wordsworth it was when he broke away from his fellow ice-skaters to find 'a silent bay'; for William Barnes it was his Orchard in Linden Lea; for Yeats it was 'The Lake Isle of Innisfree'.
Woods, rivers, mountains, ravines, cliffs and great trees are infused with memories and associations that have over the centuries assumed a mystical and mythical quality. There are things that cannot be explained rationally but survive in folklore, in custom and tradition, in stories handed down from one generation to the next, and a historic sense that the destiny of man is bound up with the spirits of Nature. William Cowper's poem 'The Yardley Oak' was popular in the nineteenth century because its growth from an acorn to its full stature and to its dying from its top downwards was seen as a parallel to the decay of England - the spirit of the tree was intertwined with the spirit of Albion. William Blake's vision of the golden pillars built over the fields from Islington to Marylebone is a victory over the druid past, and Derek Mahon finds in a forest clearing that:
Nature is often best enjoyed alone, perhaps on a walk through the countryside, when one is surrounded with the beauty of nature and immersed in the atmosphere of the place so that one's enjoyment becomes a source of refreshment and one can be aware of a presence greater than oneself. For some that presence is God, for others some pagan deity or some universal spirit, through which one hears.  Over the centuries man has hungered to bring nature under control and to impose some tidy order over the chaotic confusion and wildness in the natural world. Such attempts to tame nature are usually temporary victories. 
In his poem 'Going, Going', which was commissioned in 1972 at the request of Robert Jackson, later an MP and a member of a government enquiry into the 'Human Habitat', Philip Larkin saw that all he loved most around him was slipping away under concrete and tyres. A sense of angry regret prevails. But that was not the view of poets such as John Dyer and John Dalton, writing in the early eighteenth century; they welcomed the Industrial Revolution, 'for industry brings all her honey to the hive'. Blake was certainly opposed to industrialization, but his 'dark Satanic mills' refer, it is now thought, not to the belching chimneys of the wool and cotton mills in Yorkshire and Lancashire, but to either the Church of England or the Newtonian system. 
Farmers too, the very custodians of the countryside, now recognize their responsibility for the devastation of the bird life over the last twenty years. In that time it has been estimated that the number of skylarks has fallen by fifty percent.  Perhaps only poetry can describe how the beauty of birdsong can crystallize a unique moment of contact with nature, and evoke a sense of regret when it can be made no more.
Hopkins expresses his personal agony when his beloved poplars at Binsey were felled, and Charlotte Mew, when she saw the great plane trees coming down at the end of her garden, pleaded 'Hurt not the trees'. Francis Nowell Mundy, who was a Derbyshire magistrate and country gentleman published a poem in 1776 called 'Needwood Forest' in which he makes a great oak speak out against the axe.  But the love of trees is not simply a matter of protecting the landscape but also the recognition of a much more elemental pull that they have upon the human imagination. Great oaks became symbols of stability and national endurance, and the greenwoods were the sanctuaries for free men standing out against oppressive tyrannies. Forests and woods are part of a primeval past, impregnated with mystery and myth, places where solemn rites were performed, where sacrifices were made, where outlaws lived and where wild animals hid for security. In the eighteenth century James Hall, the Scottish antiquarian, trained saplings in the shape of arches to prove his conviction that gothic architecture was derived from the perpendicular alley formed by trees: to him the tree was a symbol of the resurrection of man.