8 Wood in LandscapeHow wood is used in Landscape ArchitectureWood as a feature of the built landscape can be found in nearly all cultures through history. Even in stone and masonary cultures with limited lumber resources, wood was used in the construction of pergolas, arbors, and other garden structures. In this chapter, the definition of wood in Landscape Design will be discussed with examples from history, as well as, the finishes used of wood in Landscape Architecture projects will also be described.

8.1 History of wood usage in Landscape8.1.1 Wood as a Landscape Material8.1.2 Wood in Roman Landscapes8.1.3 Wood in Japanese Gardens8.1.4 Wood in Modern History

8.2 Finishes on wood for use in Landscape8.2.1 Wood Finishes8.2.2 Varnish & Lacquers8.2.3 Latex Semitransparent Stains8.2.4 Latex Colour Stains8.2.5 Oil8.2.6 Wood Preserver8.2.7 Considerations for Choosing Finishes

02

8.1 History of wood usage in Landscape

8.1.1 Wood as a Landscape Material

8.1.2 Wood in Roman Landscapes

Wood, in its most natural form. was probably the earliest building material, serving as the primary resource for shelters, weapons, and fuel for the early nomadic cultures. Of all the building materials, however, it is also one of the least permanent. Unless preserved through encapsulation by mud, lava, or sand and water, thus prohibiting the cycles of water penetration and drying, a majority of the examples of wood as it was used in antiquity have completely. degraded. Most of the knowledge of early wood construction is based on frag-ments, drawings, and other written representations. Its many virtues include its relatively light weight.. ability to span long distances, flexibility, and workability.. ease of extraction and use for house and boat building caused a depletion in many parts of the ancient world, and the once-wooded landscapes of the Mediterranean region have never recovered.

In ancient Rome timbers were largely reserved for shipbuilding and similar uses, but in hillside villa gardens, expansive wood beams reached across massive stone columns and formed trellised walkways lining canals, orchards, and ornamental gardens. Rafters, trellises, and doors were also typically constructed of wood. The scale of the wood reconstruction of the peristyle and trellised walk-ways at Villa Guilia Felix illustrates how large openings between columns allow easy access inside and out (see Figure 1b). The shade from the wood members above the walkway provides relief from the heat and a contrasting play of light with the bright sun-soaked open-air garden in the center. Unlike the Greeks, who considered their houses simply as a means of shelter, Romans considered the house and its enclosed gardens sacred (Chatfield, 1991, 12). Two further examples of these early Roman preserved houses and gardens can be seen at Villa dei Vettii and the Villa of Loreius Tiburtinis in Pompeii.

Figure 8a : Wood is an important material in landscape due to its relationship with the chief elements of this art, the trees. The use of wood gives a natural tone to the design as we can see in the image on the right.

03

8.1.3 Wood in Japanese Gardens

The oldest known wood structure in the world still stands in Japan, a manifestation of the legacy of wood craftsmanship from its construction con-tinuing through its restoration. The Horyu-ji Temple, with its spectacular five-storied tower building, Rondo, and elegant gate, is hard to specifically date (see Figure 1c). The oldest buildings were in a fire in A.D. 670, and the new structures found on-site today have been continually rebuilt since the beginning of the eighth century; thus, the oldest buildings standing today, forming the central core, are approximately 1,300 years old.

Japanese craftsmanship in wood is found at the highest level of mastery in court and monastery gardens from the Heian (784-1185) to the Edo (1615-1867) period. Elegance of line, pattern of order, and harmony in joining materials are illustrated in wood pavilions, bridges, fences, gates, and teahouses. The early compounds, in which aristocratic mansions were surrounded with paradise gardens taken from descriptions of the idealistic Buddhist Pure Land, were part villa and part temple.

Each wood member was scrutinized before it was cut or carved, with the master carpenter determining 'what it wanted to be." Examples of wood and timber construction are found through-out the garden, in arching bridges spanning miniaturized rivers and in wood and bamboo fencing defining the interior spaces as separate from the exterior. In Shinden waterside pavilions the nearly transparent railings of the decks cantilevering over the ponds, along with the anchored stone foundations rising out of the water, are a remarkable integration of building and landscape. One of the most famous Japanese garden structures, the Golden Pavilion in Kinkakuji (1397, Muromachi period) carries on the Shinden style.

Figure 8b : View through the impluvium and across the peristyle at Villa Giulia Felix. Note the stone columns. wood beams and rafters of the impluvium and the masonry columns and wood beams defining the peristyle on the far side.

04

Figure 8c : The oldest known wood structure in the world, the famous five-storied tower at Horyu-ji, has been rebuilt many times and reflects the enduring tradition of timber frame construction in Japanese building.

8.1.4 Wood in Modern History

Centuries later, practitioners of landscape architecture not only pursued the design of residences but took on the design of the developing cities, the planning of cemeteries as botanical parks. and, as history has borne out, the creation of some of the greatest urban park systems in the world. The detailing of the many wooden park structures, entryways, and amenities incorpo-rated a high level of woodcraft and design.

The stylistic decisions were diverse and at times somewhat eccentric, but always in keeping with the principles of the picturesque, as piecs of bucolic countryside were being recreated in the growing urban centers of preindustrial America. Wood, in both its natural and its milled form, was commonly used for reconstruction of fencing, benches, bridges and park pavilions. Many designers of the period found inspiration in John Ruskin, writings and in the natural world itself. In an attempt to reflect this celebration of and integration into the natural landscape, many landscape architects found that wood possessed the character and natural and/or manipulated form that best expressed these natural ideals.

Examples include W S. Cleveland, work on the bridge at Minnehaha Falls in the Minneapolis park system and Calvert Vaux, spectacular rusticated arbors and pavilions, now restored in Central Park, that became a vernacular style of the picturesque (see Figure 1d). The designer probably most influenced by Ruskin's writings and who felt impelled to link art (landscape architecture) and nature to morality and the love of God was the famous landscape designer Andrew Jackson Downing. Ruskin advocated that craft will not be lost in the industrial revolution and that expression through form and craftsmanship reflect the morals and character of humanity.

In this pursuit, Downing explored and wrote about the craft of rustication, believing it most stylistically and environmentally appropriate to the rural landscape.

05

Figure 8d : A rusticated pavilion restored in 1993 in Central Park, New York.

8.2 Finishes on wood for use in Landscape8.2.1 Wood Finishes

8.2.2 Varnish and Lacquers

Wood finishing refers to the process of refining or protecting a wooden surface, especially in the production of furniture. In Landscape architecture, this may further be applicable for pergolas, gazebos, trellis, arbors and other wooden elements. Natural wood finishes, especially those that soak into the grain, are often difficult to remove, so take time to think about your requirements and choose the right product. Protection offered by natural finishes varies. Dye, for example, may offer no protection by itself. Always buy a suitable exterior formula. Consider if you want an almost invisible coat or would prefer some color or gloss. Also, think about how much time you are prepared to spend on applicationthere may be one-coat options available. Finally, look out for eco-friendly options, such as water-based varnishes and stains or products made from 100-percent natural ingredients. Natural oils and waxes are the most eco-friendly of wood finishes, although synthetic alternatives do exist. Beeswax and linseed oil are well known green finishes, but look out for safflower oil and carnauba wax as well. Water-based varnishes and stains also have good green credentials.

Varnishes and lacquers are clear and lack natural pigmentation to protect wood; thus, UV light penetrates the finish, degrading the wood below. Most of these finishes have extremely limited life spans, typically a year in exterior conditions. The use of colorless UV inhibitors has been moderately success-ful, but the weatherproofing qualities of even the synthetic clear polymers are limited, as the UV light degrades the underlying wood surfaces, undermining the adhesion. If varnishes are to be used on exterior structures, the choice of location may present the greatest opportunity for durability.

If possible, site the structure in an area that receives little or no direct

06

sunlight. because expo-sure to UV rays causes the greatest damage. Pigments can be added to both varnishes and lacquers to reveal the color and grain of the surface or to provide a surface coloring. If varnishes or lac-quers are to be used on previously finished wood, any remaining finish must be removed before refinishing is attempted. Can be used on bare wood or to protect unsealed finishes, such as dye. Covers 600 to 900 square feet per gallon. May need several coats. Apply with a brush for the best finish.

Figure 8e : The varnish coating on a wood can be seen in the image on the right.

Figure 8f : The latex color stain coating on a wood can be seen in the image on the right.

8.2.3 Latex Semitransparent Stains

8.2.4 Latex Colour Stains

Latex semitransparent stains, despite their name, do not penetrate the wood surface but, instead, leave a thin film coating on the surface. The stains are emulsions of polymers (acrylics or acrylic blends) and provide protection for most wood surfaces. They are not, however, recommended for coating decking boards.

Latex solid color stains, also called opaque stains, are both penetrating and film forming. Many solid color stains contain preservatives and water repellents, usually paraffin wax dissolved in solvents. The preservative and solvents penetrate the wood surface, leaving the pigmentation and binder on the surface, which form a film. These products are not successful on horizontal surfaces used for traffic as the pigments are not stable.Use as a finish or coat with varnish for extra durability. Apply to clean, bare wood for a true color. Covers 400 to 1,000 square feet per gallon. May need several coats. Apply with a brush for the best finish.

07

Figure 8g : The oil coating on a wood can be seen in the image on the right.

Figure 8h : The wood preserver coating on a wood can be seen in the image on the right.

8.2.5 Oil

8.2.6 Wood Preserver

8.2.6 Considerations for Choosing Finishes

Transparent finish that nourishes and protects wood. External surfaces lose their finish but stay protected. Buff to achieve mid-sheen finish. Will not penetrate a sealed surface.

For interior or exterior use. Must be applied to unsealed wood. Covers 400 to 750 square feet per gallon. Apply with a brush or cloth yearly. Highly flammable.

Prevents rot and insect damage. Available clear or colored with a matte or a semigloss finish. Both water-based and oil-based types are available.

Exterior use. Used alone, or as base coat for another natural wood finish or paint. Covers 4001,000 square feet per gallon. Apply in sections as for stain or as specified.

A number of factors an affect the performance of finishes, including the type of finish selected. moisture content, natural weathering, and the quality and species of the wood on which the finish is applied. All species of wood are susceptible to degradation from UV saturation and the natural effects of weathering.

Penetrating stains break down, but at a slower rate than unfinished wood, and pigments increase IN resistance; however. once degradation of the

08

finish begins, the pigment panicles debond and the protection is reduced. To prevent debondum, additional stain appli-cations may be required. Film-forming finishes (paints) offer two advantages. The film coating effectively blocks UV saturation and is a sacrificial coating, protecting the wood surface from abrasion. The most damaging elements to the wood and to film coatings arc moisture penetration and the UV portion of light exposure. which over time will break down a film coating.

Film finishes, providing protection against surface erosion, allow visual inspection to determine when the primer is visible and an additional coat should be applied. Many successive coats may be applied if the surface con-tact to the wood has not been disturbed. which can extend the life of the material. If water does penetrate through the film. decay below the film can be extensive and should be addressed immediately with removal of the loose layer.

Sources:BooksWood in the Landscape: A Practical Guide to Specification and Design-Daniel M. WinterbottomLandscape Architect's Pocket Book-Siobhan-VernonImages8a : http://images.landscapingnetwork.com/pictures8b : http://www.pompeiiinpictures.com/pompeiiinpictures8c : http://www.truthsimplified.com/wp-content8d : http://media-cdn.tripadvisor.com/media/photo-s8e - 8f : http://www.diynetwork.com/home-improvement/all-about-the-different-types-of-wood-finishes/pictures