Design Policy & Process
Western Field Office
Decade of Expansion
THE WRITINGS OF ANDREW JACKSON DOWNING
The landscape design of national and state parks evolved from the eighteenth- and early nineteenth-century English landscape gardening tradition of William Kent, Capability Brown, and Humphrey Repton. This tradition came to America at the beginning of the nineteenth century and was first manifested in the pleasure grounds of the wealthy along the Hudson River in New York. Country estates such as Montgomery Place were celebrated in the writings of Andrew Jackson Downing in the periodical The Horticulturalist. Downing's Treatise on the Theory and Practice of Landscape Gardening, first published in 1841, was the standard American guide for landscape gardening in the nineteenth century and was revised by a number of authors as late as the 1920s. Downing, who had visited many English landscapes and was familiar with Repton's treatises, adapted the ideas and practices of the English designers to the American landscape and fostered a strong awareness and appreciation of a native landscape that was inherently sublime and picturesque.
Downing's writings provided a philosophical basis for preserving America's natural areas and translated the idea of "wilderness," as evocative of the sublime and picturesque, into design terms. His principles reflected the landscape interests of contemporary writers, such as Nathaniel Hawthorne, Washington Irving, William Cullen Bryant, and Henry David Thoreau, and artists of the Hudson River School, including Thomas Cole and Asher B. Durand.
Montgomery Place was an estate of about four hundred acres devoted to "pleasure grounds and ornamental purposes." Its "natural boundaries" consisted of an oak wood, a wooded valley with a broad stream containing many waterfalls, the post road, and, to the west, the Hudson River. Downing praised the natural specimens of hemlock, lime, ash, and fir and described the broad undulating lawn, margined with rich foliage and bordered by the river, that provided a view of the distant Catskills. He was elated by the panoply of colors seen at sunset from the terrace or the pavilion: "The eye is filled with wonder at the various dyes that bathe the receding hillsthe most distant of which are twenty or thirty miles away." 
Downing cultivated in the American mind an aesthetic appreciation of wild places and stimulated images of the picturesque qualities of such places. Downing was intensely aware of the tremendous power that primeval nature, with its dramatically changing landform, variations of light and shadow, sounds of moving water, and enveloping vegetation, could exert on the human senses. Influenced by the popular writings of William Gilpin and Sir Uvedale Price, he described the Wilderness at Montgomery Place, a wooded area of the estate that retained the natural character of the Hudson River Valley and evoked feelings of the sublime:
Leaving the morning walk, we enter at once into "The Wilderness." This is a large and long wooded valley. It is broad, and much varied in surface, swelling into deep ravines, and spreading into wide hollows. In its lowest depths runs a large stream of water, that has, in portions, all the volume and swiftness of a mountain torrent. But the peculiarity of "The Wilderness," is in the depth and massiveness of its foliage. It is covered with the native growth of trees, thick, dark and shadowy, so that once plunged in its recesses, you can easily imagine yourself in the depths of an old forest,far away from the haunts of civilization. Here and there, rich thickets of the Kalmia or native Laurel clothe the surface of the ground, and form the richest underwood. 
Sparing no picturesque detail, Downing proceeded to describe the experience of moving through the wilderness. The sequence of changing vistas was central to Downing's vision. After crossing an "airy looking rustic bridge," one was plunged for a moment into the thicket and emerged again in full view of the first cataract. By "a flight of steps made in the precipitous banks of the stream," one entered another scene, which was "scarcely less-spirited and picturesque, and proceeded to the lake and after that another waterfall. The memory of what was past and the anticipation of what lay ahead heightened the individual's response. 
The untamed ambiance of the place was relieved by paths, "ingeniously and naturally conducted to reach the most interesting points." Manmade features bridges, steps, seats, and sheltersalong the way provided access, comfort, and shelter and were themselves picturesque details. A great variety of rustic seats "formed beneath the trees, in deep secluded thickets, by the side of the swift rushing stream, or on some inviting eminence," enabled one to fully enjoy the richly wooded valley. 
Downing's description of Montgomery Place illustrated the meaning of scenery, vista, enframement, and sequence, and stressed the role that rustic manmade features played in enhancing the individual's enjoyment and experience. Downing's romantic vision of the sylvan retreatwith its broad vistas, rustic seats, rock steps, thatch-roofed shelters, dense thickets of native wood, and expansive terraces and porches from which distant views across open lawns could be enjoyedcaptured the imagination of the designers of parks and suburban homes alike in the nineteenth century. Downing's principles would continue to attract followers well into the twentieth century, even after other styles gained popularity.
Downing's Theory and Practice of Landscape Gardening established the key components of the pleasure ground. Apart from a fashionable manor house and formal gardens, pleasure grounds contained serpentine drives, open meadows, winding paths, picturesque rockwork, rustic bridges, and wooded glades. Rustic summerhouses and pavilions of unpeeled logs and branches provided shade and seating for rest and contemplation. Natural elements groves of hemlocks and pines, bubbling streams, rock outcrops, waterfalls, and scenic riverviewsdefined the wild and untamed areas of these places.
RUSTIC SEATS, SHELTERS, AND BRIDGES
Downing identified the "embellishments" that pleasure grounds should possess. Many were functional, adding to the comfort of visitors while enhancing the beauty of the natural setting. The shelter, with its seat and view, was an essential furnishing. Such structures provided shade, seating, comfort, and rest. As overlooks or windows for contemplating the natural scenery, shelters served as the objective of walks through the woods. Downing urged his readers to locate seats at points providing "agreeable prospects or extensive views of the surrounding country," so they could afford the double benefit of comfort and view. They could also be the object of visual interest from afar. 
There was no limit to the variety of forms and patterns in which rustic seats, arbors, summerhouses, and such structures could be constructed. In all cases, these structures were to be appropriate to their location and use and in harmony with the scene; thus, a classic temple pavilion could crown a prominent knoll, but a rustic seat demanded a secluded quiet place where "undisturbed meditation could be enjoyed." Downing's idea of harmonization was to blend the structure into its setting by using woodland materials and by imitating the natural form of nearby trees. He advocated rustic constructions made from the trunks and branches of trees in their natural, unpeeled, and often twisted forms. Thatching and climbing vines added attractive details to roofs and helped blend structures with surrounding vegetation. Not only did the materials of Downing's shelters echo the textures and colors of their surroundings, but also the slender sinuous elements repeated the vertical and arching forms of tree trunks and branches. 
Downing provided numerous illustrations of suitable rustic shelters that would serve as the prototypes for public and private pleasure grounds for decades to come. His "covered seat or rustic arbor" was a circular form with a thatched roof of straw supported by twelve posts and window openings framed by branches, each about three inches in diameter, fastened together to form an irregular lattice pattern. Bark and unpeeled logs were also suggested roofing materials. This type of naturalistic construction was carried to its extreme in the example of a shelter built around a living tree, with both roof and sides forming an open lattice of branches, and the whole "covered by a grape, bigonian, or some other vine or creeper of luxuriant growth." Downing encouraged the construction of shelters in the form of "prospect towers" from which observers could gain a bird's-eye view of the surrounding country. Downing's rustic prospect tower was three stories in height with a double thatched roof. It had rustic pillars or columns joined by a fanciful lattice of rustic branches; a spiral staircase wound around the interior of the platform to the second and third stories, where visitors could enjoy the view in the shade of the thatched roof. Another example showed a circular thatch-covered seat surrounding a cabinet where collections of "minerals, shells, or any other curious objects for which an amateur might have a penchant" or the "geological or mineralogical specimens of the adjacent neighborhood" could be displayed. 
Downing's shelters would have corollaries in the lookouts, fire towers, picnic shelters, nature shrines, and observation towers of the national and state parks. Although his designs using twisted unpeeled branches would eventually be rejected in favor of sturdier structures built of large peeled logs or native stone, Downing established the link between a structure's material and its setting and set the precedent for the use of native materials in naturalistic forms as a technique for harmonizing manmade structures with a natural setting.
A similar concern for naturalism extended to the design of bridges. He recognized both the functional necessity and the decorative value of bridges. Readers were to consider the scale of the stream to be crossed, the character of the surroundings, and the appropriateness of materials to the site. Downing wrote,
Downing's design for a rustic bridge of unpeeled logs set upon stone abutments provided the prototype for the footbridge of public parks. Although primitive in form, the prototype and its method of construction would influence the evolution of sturdier bridges on national park foot and bridle trails and even park roads in the twentieth century. Downing described the bridge:
Bridges of entwined unpeeled branches and tree trunks, inspired by Downing, appeared in urban parks in the late nineteenth century. The designs for rustic bridges in Henry Tyrrell's Artistic Bridge Design of 1912 included a double-span example used for foot traffic in a Minneapolis park that was described as "ordinary but satisfying because of its fitness" to its location over a ravine and surrounded by forest. Tyrrell's book also, in contrast, illustrated a sturdy timber type from Rock Creek Park in the District of Columbia.
Although constructions of unpeeled trunks remained popular as backyard garden furnishings, by 1917 landscape architects such as Frank Waugh were criticizing them as affectations and discouraging their use. Bridges made of sturdy, peeled members were more likely to withstand insect attack and rotting. The national park designers in the 1930s cautioned against such examples of "twig" architecture. In public parks, the twisted, narrow, peeled branches of Downing's bridge gave way to sturdier bridges made of larger peeled timbers with fewer irregularities. The logs for rails, stringers, braces, and trusses were selected for durability, scale with the surrounding forest, and general naturalistic character. Bridges closer in style to the Rock Creek bridge could be designed to carry varying loads and to serve foot, bridle, or automobile traffic. Among the grandest of these were Yellowstone's Log Bridge and Mount Rainier's Shaw Creek Bridge. Exceptions to the bold new timber designs were several bridle trail bridges built of slender unpeeled branches across Indian Creek in Yosemite Valley in 1926; by the mid-1930s, however, they were already in need of replacement. 
Rockwork was central to naturalistic landscape design. When it occurred in nature, it added greatly to the scenic interest of a woodland, ravine, or cliff. Downing drew attention to the inherent beauty of natural outcrops of rock, especially as they created waterfalls, inclines, and precipitous peaks affording scenic vistas. He saw rockwork of native stones as a compositional element that could be introduced and manipulated, fashioned into naturalistic groupings, or enhanced by plantings.
Rockwork could also be contrived artificially to imitate nature. Downing offered detailed instructions for developing rockwork that were used by generations of landscape architects and, in the twentieth century, by designers of national and state parks. Used as a construction material, rock could unite and harmonize manmade elements with a park's natural setting. Downing called for the use of moss and lichen-covered rocks, gathered locally, set in artificial groupings such as a rocky bank. He encouraged the study of natural groupings, for great skill is necessary to achieve, in artificial rockwork, "a natural and harmonious expression." Downing urged the designer to begin his rockwork in a place where a rocky bank or knoll already partially existed or where an arrangement of rocks would be in keeping with the form of the ground and the character of the scene. He advised,
Rocks were to be embedded in the soil to one-half or three-fourths of their depth to create the appearance of a natural rocky ridge "just cropping out."
Downing also gave detailed instructions for adding plantings:
The rockwork once formed, choice trailing, creeping, and alpine plants, such as delight naturally in similar situations may be planted in the soil which fills the interstices between the rocks. When these grow to fill their proper places, partly concealing and adorning the rocks with their neat green foliage and pretty blossoms, the effect of the whole, if properly done, will be like some exquisite portion of a rocky bank in wild scenery, and will be found to give an air at once striking and picturesque to the little scene where it is situated. 
Moist, secluded areas, such as woodland streams and ponds, and caves or rocky spots having a source of water offered ideal sites for enhancing rockwork, either natural or naturalistic, with moisture-loving plants such as ferns, mosses, low shrubs, and climbing plants like wild clematis. Where a place was naturally picturesque with rocky banks, the best thing to do was to leave the scene alone or, if necessary, enhance it by planting beautiful shrubs and climbers. Rockwork was inappropriate where rocks of any kind were unknown. 
Recognizing the aesthetic possibilities of combining rocks, water, and vegetation, Downing offered instructions for creating a "rustic fountain." A conduit pipe was concealed among a group of rocks, and water flowing through it spilled out in the form of a cascade, a weeping fountain, or a perpendicular jet. The water could then fall into little basins among the rocks or at the foot of the rockwork. "The cool moist atmosphere afforded by the trickling stream," in Downing's mind, offered "a most congenial site for aquatic plants, ferns and mosses." 
Downing introduced Americans to the English gardener's aesthetic preference for rough stone surfaces covered with moss and lichens and worn by weather and time. This aesthetic would continue to appeal to park designers working in the rustic tradition and serve as the basis of naturalistic rock design both in landscape design and in the construction of walls, bridges, and buildings well into the twentieth century. The use of native stone, in boulder and split form, would be expanded in later treatises on landscape architecture by Samuel Parsons and Henry Hubbard. Native rock would have numerous applications in the design of national and state parks, from the embedding of rough boulders as guardrails along roads or barriers in campgrounds to the massive boulder foundations and chimneys of park buildings. It would appear in the construction of park structures of all sizes, from water fountains to refectories and administration buildings. Park designers during the New Deal also used Downing's ideas to create naturalistic lakes, channelize and riprap streams, create waterfalls, rehabilitate springs, and construct buildings that emerged naturalistically from the ground. Downing's advice on planting was followed to beautify springs, control erosion along streams, restore eroded or disturbed areas, plant foundations and bridge abutments, and naturalize road and trail cuts.
ROADS AND WALKS
Emphasizing the importance of circulation within the pleasure ground, Downing specified several types of roads and paths. His ideas, many drawn from Repton, would be developed in the public parks and parkways of the late nineteenth century and would directly influence the location and design of roads in national and state parks in the twentieth century. First was the approach road, which connected the estate or pleasure ground with the public highway and led to the house. Developed with artistic skill in easy curvilinear lines, it wound through the grounds until it arrived at the main house at an angle so that the facade and one of the side elevations could be viewed. The road was to be laid out in gradual, graceful curves that seemed to flow naturally up and down the contours of the land and in and around groups of trees. Downing wrote, "The most natural method of forming a winding Approach where the ground is gently undulating is to follow, in some degree, the depression of the surface and to curve round the eminences." Groups of trees were to be planted inside the curves of the road so that when the trees were grown it would appear that they had always stood there and that the road turned to avoid them. Views of the house were to be carefully planned, and viewpoints sited on the ground. Right angles were to be avoided where the approach road left the highway and where roadways intersected. 
Next was the drive, intended to lead visitors in carriages or on horseback to points of interest and to enhance their enjoyment of the grounds. Intersecting with the approach road, the drive proceeded in a similar curvilinear fashion through the grounds, revealing interesting spots and views or simply giving access to outlying areas of the estate. Finally came the walks, laid out for purposes similar to those of the drives but exclusively for travel by foot. Walks were to be laid out in easy flowing curves so that they opened up new scenes to the beholder and thereby led the traveler forth. What Downing called the "genius of a place" was to dictate the nature of a walk so that it corresponded to the scene through which it passed, being rugged where the scene was rough and picturesque, being smooth and easy where a scene was gentler and more refined. Walks were to be dry and firm. Downing described the varied character of such walks:
Some may be open to the south, sheltered with evergreens and made dry and hard for a warm promenade in winter; others formed of closely mown turf, and thickly shaded by a leafy canopy of verdure, for a cool retreat in the midst of summer. Others again may lead to some sequestered spot, terminate in a secluded rustic seat, or conduct to some shaded dell or rugged eminence, where an extensive prospect can be enjoyed. Indeed, the genius of the place must suggest the direction, the length, and number of the walks to be laid out, as no fixed rules can be imposed in a subject so everchanging and different. 
Trees, in the form of plantations and small groups, had aesthetic as well as functional value. Natural groups were "full of openings and hollows, of trees advancing before or retiring behind each other; all productive of intricacy, of variety, of deep shadows and brilliant lights." Downing's writings on trees would influence the identification of natural areas to be set aside for parks, the selection of park boundaries, and the preservation or development of certain areas within a park. 
Trees also had great value for enframing desirable vistas and screening undesirable ones. Downing wrote,
Wood, in its many shapes, is then one of the greatest sources of interest and character in Landscapes. Variety, which we need scarcely allude to as a fertile source of beauty, is created in a wonderful degree by a natural arrangement of trees. To a pile of buildings, or even of ruins, to a group of rocks or animals, they communicate new life and spirit by their irregular outlines, which, by partially concealing some portions, and throwing others into a stronger light, contribute greatly to produce intricacy and variety, and confer an expression, which, without these latter qualities, might in a great measure be wanting. By shutting out some parts, and inclosing others they divide the extent embraced by the eye into a hundred different landscapes, instead of one tame scene bounded by the horizon. 
Trees created unity between buildings and the land and could be used to enhance the appearance of buildings or other structures. Trees could also be used to conceal buildings, to beautify roads and paths, and to provide natural boundaries around a property and block out scenes beyond. Downing wrote,
Buildings which are tame, insipid, or even mean in appearance, may be made interesting and often picturesque, by proper disposition of trees. Edifices, or parts of them that are unsightly, or which it is desirable to partly or wholly conceal, can readily be hidden or improved by wood; and walks and roads, which otherwise would be but simple ways of approach from one point to another, are, by an elegant arrangement of trees on their margins, or adjacent to them, made the most interesting and pleasing portions of the residence. 
The image of the picturesque, visible in what Downing called "spiry-topped" trees, engendered the most imaginative design possibilities for natural areas. Although parks frequently had a combination of deciduous and evergreen trees, it was the evergreen, in the form of stately pines, hemlocks, balsams, firs, redwoods, and sequoias, that inspired the greatest awe in park visitors. Downing described the effect of spiry-topped trees:
The situations where they have most effect is among rocks and in very irregular surfaces, and especially on the steep sides of high mountains, where their forms and the direction of their growth seem to harmonize with the pointed rocky summits. Fir and pine forests are extremely dull and monotonous in sandy plains and smooth surfaces (as in the pine barrens of the southern states); but among the broken rocks, craggy precipices, and otherwise endlessly varied surfaces (as in the Alps, abroad, and the various rocky heights in the Highlands of the Hudson and the Alleghenies, at home) they are full of variety. . . . In all grounds where there are abruptly varied surfaces, steep banks, or rocky precipices, this class of trees lends its efficient aid to strengthen the prevailing beauty, and to complete the finish of the picture. 
In "Ornamental Trees and Shrubs in North America," first published in 1835 in Hovey's Magazine of Horticulture, Downing praised many American trees, saying that no country on the globe produced a greater variety of fine forest trees than North America. Downing was interested in the beauty of each tree as an individual specimen or as part of a grouping. He had little concern for native habitat or groupings based on natural ecological relationships. He treated North American species as he did those introduced from abroad, as part of a full and rich palette from which the designer could fashion an estate, park, or country home. Of the deciduous trees of North America, he praised the oak for its "broad ample limbs and aged form" that gave "a very impressive air of dignity" to a scene. He wrote of the "pendulous" branches of the American elm, the "light foliage" of the birch, the "cheerful vernal appearance" of some maples, the "delicate" leaf of the locust, and the "heavy masses of verdure" produced by the beech. 
While he praised the Kentucky coffee (Gymnocladus canadensis) and the deciduous cypress (Taxodium rich), he considered "the most splendid, most fragrant, and most celebrated ornamental production" of American woodlands to be the Magnolia grandiflora of the southern states. Among native evergreens, he prized the white pine (Pinus strobus), the spruces of the Middle Atlantic states (Pinus alba, rubra, and fraseri), the balsam fir (Pinus balsamea), and the arborvitae (Thuja occidentalis). Premier among the evergreens was the hemlock (Abies canadensis), of which he wrote, "In its wild haunts, by the side of some steep mountain, or on the dark wooded banks of some deep valley. it is most often a grand and picturesque tree, when, as forest land, it becomes gloomy and monotonous." 
Noting the beauty of America's autumnal foliage, known throughout the world, Downing regretted the increasing loss of these "wide masses of rich coloring" to the axe of the woodman. He urged the mass planting of colorful groupings that included the scarlet of the scarlet oak (Quercus coccinea), the deep crimson of the dogwood (Cornus florida), the yellow and deep orange of the tupelo and sour gum (Nyssa villosa) and different species of maple (Acer spp.), the reddish purple of the sweet gum (Liquidamber styraciflua), and the somber purple of the American ash (Fraxinus americana). He noted that the intermediate shades came from the numerous species of birches, sycamores, elms, chestnuts, and beeches and that the effect of the whole was "thrown into lively contrast by a rich intermingling of the deep green in the thick foliage of the pines, spruces, and hemlocks." 
Downing offered complete instructions for transplanting large trees in The Horticulturalist of January 1850. Relying heavily upon Henry Stuart's instructions published about fifteen years earlier in Great Britain, Downing offered a simple formula: "First, the greatest respect for the roots of a tree, and some knowledge of the functions of the roots and branches; second, a pair of large wheels, with a strong axle and pole; third, practical skill and patience in executing the work." He noted that elms and maples were well adapted for transplanting, while oaks or hickories were not because of their deep-growing taproots. 
Although Downing is most often acclaimed for his descriptions of foreign specimens and cultivars, Downing did not overlook the value of many fine American cultivars. At Montgomery Place he praised the ash, hemlock, and fir, as well as the flowering laurels that provided a rich underwood in "the Wilderness." Frank Waugh, one of Downing's strongest twentieth-century followers, recognized in 1917 that Downing did much to stimulate an appreciation for America's native plants. In addition to the native trees of the United States, Downing praised and encouraged the planting of many native shrubs and ground covers, which he valued not only for the inherent beauty of their foliage and flowers, but also for their ability to enhance the character of a natural scene.
Writing in The Horticulturalist on "Neglected American Plants" in 1851, Downing regretted the "apathy and indifference of Americans to the beautiful sylvan and floral products of their own country." Americans, he claimed, imported every new and rare exotic from abroad but remained unappreciative of native plants. He wrote, "How many rich and beautiful shrubs, that might embellish our walks and add variety to our shrubberies, . . . are left to wave on the mountain crag, or overhang the steep side of some forest valley; how many rare and curious flowers. . . bloom unseen amid the depths of silent woods, or along the margin of wild water-courses." 
Downing believed that American woods and swamps were full of the most exquisite plants, many of which could embellish "even the smallest garden." He called the azaleas, laurels, rhododendrons, cypripediums, and magnolias the "loveliest flowers, shrubs, and trees of temperate climates." He praised the English fashion of planting masses of American mountain laurel, azaleas, and rhododendrons. Downing drew attention to two native broad-leaved evergreen shrubs abundant in the middle statesthe holly (Ilex opaca) and laurel (Kalmia latifolia)and urged Americans to plant them in their pleasure grounds:
Let our readers who wish to decorate their grounds with something new and beautiful, undertake now, in this month of May (for these plants are best transplanted after they have commenced new growth), to plant some laurels and hollies. If they would do this quite successfully, they must not stick them here and there among other shrubs in the common borderbut prepare a bed or clump, in some cool, rather shaded aspecta north slope is better than a southern onewhere the subsoil is rather damp than dry. The soil should be sandy or gravelly, with a mixture of black earth well decomposed, to retain moisture in a long drought. A bed of these fine evergreens, made in this way, will be a feature in the grounds, which after it has been well established for a few years, will convince you far better than any words of ours, of the neglected beauty of our American plants. 
In an essay, Vines and Climbing Plants," Downing praised the Virginia creeper (Ampelopsis hederacea). Calling it the American ivy and comparing it to English ivy. he wrote,
The leaves are as large as the hand, deeply divided into five lobes, and the blossoms are succeeded by handsome dark blue berries. The Virginia Creeper is a most luxuriant grower, and we have seen it climbing to the extremities of trees 70 or 80 feet in height. Like the Ivy, it attaches itself to whatever it can lay hold of, by little rootlets which spring out of the branches; and its foliage, when it clothes thickly a high wall, or folds itself in clustering wreaths around the trunk and branches of an open tree, is extremely handsome and showy. Although the leaves are not evergreen, like those of the Ivy, yet in autumn they far surpass those of that plant in rich and gorgeous coloring which they then assume. 
Downing also praised the wild grape for its ability to create a verdant canopy and drapery-like effects. He noted the value of other native climbing plants, including bittersweet, pipe-vine or birthwort, clematis, trumpet creeper, wisteria, honeysuckle, and climbing roses, all of which had native forms in the United States. Downing encouraged the planting of climbing vines to relieve the bleak sun-bleached elevations of country cottages. 
National park designers would highly value the native vegetation of the parks. Although they studied natural patterns of vegetation, they frequently chose the more ornamental flowering shrubs, climbing vines, and ferns and the most picturesque trees of an area's natural community to use as the dominant materials for planting around park buildings, roads, and bridges. Aesthetics often determined the selection of materials to be preserved or transplanted from areas being cleared for construction or selectively thinned for campgrounds, roads, or forest protection. Although many of the native species of the western parks were unknown to Downing, they possessed qualities comparable to those praised by Downing.
Where species praised by Downing existed in nature, they readily became favored materials in the palette of the park designers. The qualities of many of these species helped serve the purposes for which the parks had been set aside. Laurels, rhododendrons, and azaleas were used for screening and decorative purposes along the scenic drives of the Blue Ridge in Virginia and North Carolina. Virginia creeper was planted in the interstices of freshly cut rocks along Shenandoah's Skyline Drive, while laurels and azaleas were planted in masses on the drive's flattened slopes. Douglas firs, western hemlocks, and Alaskan cedar were used at Longmire to blend the village with the dense forests of Mount Rainier. Elsewhere, corollaries were found, such as the deciduous azalea (Rhododendron occidentale) and chinquapin (Castanopsis sempervirens) of Yosemite, the laurels (Umbellularia californica) of Sequoia, the salal (Gualtheria shallon) of Mount Rainier, the junipers (Juniperus osteosperma) of Grand Canyon's South Rim, and the evergreen sumac (Rhus lanceolata) of Big Bend. This appreciation for native species carried over into state parks, where rhododendrons (Rhododendron maximum) were planted along trails and at overlooks in Tennessee, birch (Betula alleghaniensis) in Michigan, laurels (Kalmia latifolia) in Pennsylvania, and yaupon (Ilex vomitoria), a native holly. in central Texas.
Downing's principles established an ethic for landscape preservation and harmonization that would reach maturity in the work of the National Park Service in the 1920s and 1930s. Downing fostered an appreciation of landscape character and the sequence of landscape effects. In this he established an aesthetic basis for the preservation of natural scenery and its use for pleasure and enjoyment. He introduced the fundamental concepts of selecting viewpoints, enframing vistas, and moving the visitor through a sequence of views and scenes along curvilinear paths and steps to ensure pleasure and comfort while fostering appreciation and sensibility. He stimulated an appreciation for vegetation and rockwork as objects to be preserved and as vital design elements in enhancing the beauty of a place or scene and in blending the manmade object with its natural setting. The conceptual foundation provided by the private pleasure ground was consciously adapted in the setting aside of natural reserves for public use and enjoyment. Yellowstone National Park, when established by law in 1872, was envisioned as "a public park or pleasuring-ground for the benefit and enjoyment of the people." 
The various components of the nineteenth-century pleasure ground would find practical and utilitarian counterparts in national and state parks in the twentieth century. The gatehouse would become the entrance station. Summerhouses would become overlooks and picnic shelters. Rustic seats would become sturdy benches and picnic tables. Moss- and lichen-covered rocks would be incorporated into the foundations and walls of park structures while natural outcrops and formations would be developed as points of interest and picturesque elements along trails and roads. Woodland paths would become rugged hiking and bridle trails through which visitors experienced the natural beauty of the parks. The circular drives would become the loop roads that facilitated the flow of traffic in campgrounds and picnic areas or that encircled parks to provide access and scenic views from many points. The prospect tower on the crest of a hill, which allowed visibility in all directions, would be transformed into a functional fire lookout or observation tower. And even Downing's cabinet of local curios would find its successor in trailside museums and nature shrines. Plantations of native trees, evergreen wherever appropriate, would be preserved or planted to screen undesirable views or structures. Spiry-topped trees, flowering shrubs, ferns, and climbing vines from Virginia creeper to wild clematis would be planted and transplanted to naturalize areas disturbed by construction, to erase the lines between manmade structures and natural settings, and to integrate development into the natural surroundings of the park. The ideas of Downing and American practitioners of the English gardening style would evolve through several stages, however, before being transformed into the policy and practices of the National Park Service.