Landscape and ornamental trees are an important part of human life. They provide shade and beauty around homes, schools, markets and shopping areas, places of work, along streets and highways, in city parks and other areas. They also help conserve energy and the quality of air, water and soil.
Many conifers are important landscape and ornamental plants and fulfil
many functions in landscape design. Virtually all countries have some level
of nursery industry, which offer for sale planting stock, including conifers,
for landscape and ornamental purposes. Small-scale nursery operations are
often an excellent opportunity for small business or family run enterprise.
Trees have been used as ornamental plants since the earliest of times. More than 4 000 years ago, the Egyptians wrote about trees being transplanted with a ball of soil around their roots. Some trees were moved up to 2 400 km by boat. In Greece, Theophrastus (370-285 BC) and Pliny (AD 23-79) gave instructions for tree planting and care. Many books on the care of trees and woody shrubs have been written since those early times.
During the Middle Ages, botanical gardens contained primarily plants of medicinal importance and fruit and nut trees. Later, the gardens of private estates contained many exotic plants introduced via trade and travel. Many of these gardens are now public and are great sources of information and recreation.
By the early 1700s, trees were being planted with some frequency in the cities and estates of Europe. During the early settlement of North America, trees were cut to make room for farms and communities. During the late 1700s, however, trees were being planted in town squares. Unfortunately, after the trees were planted, few received care, except perhaps those on large estates. As settlers migrated west into the open prairies, they planted seeds of fruit trees and other trees to shelter their homes from high winds.
In the early 1900s, national research institutes in Europe and North America began to study fruit and forest trees and by the 1950s, these institutes began working on problems associated with landscape and ornamental trees. The need for this research was accelerated with the introduction of several major pests and disease, which caused serious problems with both forest and ornamental trees (e.g. Dutch elm disease, Ophiostoma ulmi and white pine blister rust, Cronartium ribicola). Experiment stations, botanical gardens, arboretums and some large plant nurseries have long been involved in the introduction and evaluation of landscape materials that are able to tolerate the rigours of the urban environment. These events led to the development of the science of arboriculture, the planting and care of trees and other woody plants (Harris 1976).
Ornamental trees provide a basic contact with nature and heighten pleasure in human surroundings. Their value is difficult to quantify in economic terms but some of the aesthetic benefits they can provide are:
Trees can have significant effects on the microclimate of areas of heavy human population. They absorb heat as they transpire, provide shade that reduces solar radiation and reflection can reduce or increase wind speed and can increase fog precipitation and snow deposition (Harris 1976). Trees can have a significant beneficial effect on the cost of winter heating and summer cooling of buildings. They break up urban "heat islands" by providing shade. It has been estimated that the shade provided by strategically placed trees near a residential home can reduce air conditioning costs by 30-50 percent and trees planted as windbreaks around buildings can reduce winter heating energy use by 4 to 22 percent (Ciesla 1995, Sampson et al. 1992).
Many conifers are used as ornamental and landscape plants. Desirable characteristics of plants selected for this purpose include foliage colour and density, overall form, growth rate (both fast- and slow-growing plants may be desired) and ability to grow and survive under a wide range of climatic and soil conditions. Some species with relatively restricted natural ranges, suggesting that they are not adaptable to wide range of conditions, have become popular plants for landscape and ornamental purposes in many parts of the world. A classic example is the Colorado blue spruce, Picea pungens, which occurs in mid- and high-elevation riparian zones in the states of Colorado, Utah, south-eastern Idaho and Wyoming, United States. The unusual blue-grey colour of its foliage has made it a highly desired landscape and ornamental tree and its ability to grow under a wide range of conditions, despite its limited natural range, has allowed it to be widely planted across Europe and North America.
Genetic variability within species is another desirable trait in trees and plants used as ornamentals. Many conifer species have one or more distinct varieties. Varieties are considered to be one step below the species level in the taxonomic hierarchy (e.g. Cupressus arizonica var. glabra) and are characterized by having distinct characteristics of foliage or form but are inseparable at the species level. Varieties appear in nature, are genetically stable and reproduce from seed (Harrison 1975). For example, Juniperus communis, a tree found in boreal and cold temperate forests of the Northern Hemisphere, has eight recognized varieties based on foliage and form characteristics (Vidalokovic 1991) (Table 3.1). Cultivars are mutations or distinct forms of plants, initially found in nature, and propagated asexually by cutting or grafting with the objective of maintaining those characteristics for a saleable plant (Harrison 1975). Cultivars are not part of the classic Linnean taxonomic hierarchy. Cultivar names have been developed by the nursery industry to reflect the characteristic of the plant, the location where it was discovered, its discoverer, etc., but are not always latinized. Examples of cultivar names include "Blue Pacific, Gold Splash, Erecta, Pyramidalis, Weckii." Cultivariants are cultivars, which appear somewhat different from their vegetative parents due to propagation from non-typical foliage (Harrison 1975).
Varieties of Juniperus communis and their characteristics
|Prostrate form up to 1 m high,
shoots ascending, needles up to 15 mm long, often directed upwards.
A dense alpine shrub, more or less globose, up to 2.5 m high. Needles 5-12 mm long, sharply pointed.
Prostrate form with broad foliage, 1.7-2 mm wide, fruit globose and flat topped.
Shrub up to 1 m high with slender branches. Needles 7-10 mm long, less curved and thinner than montana.
Prostrate shrub with branches up to 1 m long. Needles thick; 10 mm long and 2.2 mm wide, sickle formed, sharply pointed with a blue-white band above.
Very prostrate, 20-50 cm high, branches densely arranged, branchlets short. Needles ascending along the shoot, 4-8 mm long, 1-2 mm wide.
Similar to montana but with less curved needles, 1-1.2 mm wide, fruit globose, rounded at the top and containing only one seed.
First order branches horizontally spreading while others are pendulous.
|Canada, northern United States.
Algeria, Italy (Sicily and Appenine Mts,) S.E. Europe, Crimea, Caususus.
Japan (Mountains on islands of Hokkaido and Honshu).
Europe (Alps, Carpathian and Sudeten Mts, Yugoslavia in Gorski Kotar
and Dinaric Alps, Macedonia).
Mountains of northern California, Oregon and Washington, United States
Europe (Alpine and subalpine regions, often in peat bogs), North Asia,
Japan (Mountains of Hokkaido and Honshu Islands).
Source: Vidakovic (1991)
Many species of the genus Juniperus have a large number of recognized varieties and cultivars, which are popular landscape materials. They range from low, prostrate forms that are popular for borders, edging and ground cover, to small trees with pyramidal or columnar forms. In addition, there are cultivars with variegated yellow and green foliage. The same is true for the species of the genus Chamaecyparis, especially C. lawsoniana, which has over 200 recognized cultivars based on tree form and foliage colour (Vidakovic 1991). This species was once a major component of a large nursery and landscape industry in the Pacific north-western United States until a virulent root pathogen, Phytophthora lateralis, appeared in the nurseries where this species was being grown during the late 1930s and destroyed the viability of this species as a landscape material in the Pacific north-west (Hepting 1971). Blue spruce, Picea pungens, has 38 described cultivars, many of which (e.g. Argentea, Glauca, Koster, Moerheim and Thomsen) have a foliage colour that is a more distinctive silver-blue than is normally seen in natural forests of this species (Vidakovic 1991).
Dwarf conifers, which may be less than a meter high when mature, are
a valuable group of landscape materials. They can be either varieties or
cultivars and can appear in a wide range of genera and species. They are
popular in rock gardens, around garden pools, in small, formal gardens
and as ground cover plants (Welch 1979). In any given location, exotic
conifers are often popular landscape materials. This is especially true
of people interested in growing plants who prefer to have something "new
and different." Many North American conifers, such as Picea pungens,
which has already been mentioned, Thuja occidentalis (see textbox)
and Chamaecyparislawsoniana have become popular landscape
and ornamental trees in Europe.
"Arborvitae", which means "tree of life", in Latin is a common name for Thuja occidentalis, a tree found in eastern Canada and the United States. The name is said to have been given to this species by the king of France during the early sixteenth century.
The name originates from the French expedition into Canada led by Jacques Cartier, which led to the discovery of the St. Lawrence River. During the expedition, the members of Cartier’s team were affected by scurvy. Friendly natives they encountered along the way gave them a decoction believed to be made from an extract of the foliage of this tree. Believing themselves to be cured by the extract, in gratitude they carried specimens of this tree back to France.
It is in this way that the first North American tree may have been introduced into Europe, where it soon found favour as an ornamental (Harlow and Harrar 1950).
Members of the genus Abies are popular coniferous ornamentals because of their conical growth, v-shaped crown and dark green foliage and are widely used in Europe, North America and Asia. Widely used species include A. alba (Europe), Spanish fir, Abies pinaspo, Greek fir, Abies cephalonica, Algerian fir, A. numidica, A. cilicica of Asia Minor, Nordmann fir, A. nordmanniana. Popular Asian species are A. firma, A. homolepis, A. veitchii, and A. koreana. In the United States, A. concolor, A. grandis, A. amabilis, A. magnifica and A. procera are popular ornamentals. Many dwarf forms are available for rock gardens and ornamental purposes (Tang-Shui Liu 1971).
Norfolk Island pine, Araucaria heterophylla, is widely used in many tropical areas as a landscape plant, especially in the Hawaiian Islands and the Philippines (Ntima 1968) . It is popular because of its symmetry and regular whorls of branches. Among other areas, it is commonly planted along Australia’s East Coast (Boland et al. 1984) (Fig 3.1).
Figure 3.1: Araucaria columnaris is widely used as a landscape tree in the tropics (Lanai City, Lanai, Hawaii, United States).
The purpose of any landscape is to look pleasing to the eye. Landscapes can be attractive if they consist of only conifers or a mixture of conifers and broad-leaved trees but tend to have a greater year round appeal if they include a portion of conifers. This is especially true in temperate climates where most broad-leaved species are deciduous. Some special uses of conifers in landscape design are described in the following sections.
Conifers are desirable trees to plant because of the varied foliage colours that they have to offer. These range from different hues of green, grey or blue to exotic golds or silvers. The purpose of different foliage colours in a landscape is to create interest and variety. Too much green, while restful to the eye, can become tiring and uninteresting (Rushforth 1987). A number of conifers, such as Picea pungens, Cryptomeria japonica and Cupressus arizonica have foliage with a blue cast. Others, such as Abies concolor, have foliage with a distinct grey-green colour. Still others, such as Taxus baccata, Tsuga canadensis and Pinus radiata have a deep green foliage colour. A number of cultivars have golden or yellow coloured foliage. Several conifer genera, Larix, Pseudolarix, Metasequoia and Taxodium, can add fall colouring to a landscape.
Specimen and character trees
The purpose of a specimen or character tree is to have a shape or form that will be attractive to look at throughout the year. They can be used in a variety of different situations including marking the edge of a vista or characterizing a particular space. The size of a specimen tree must be in relative proportion to its surroundings. If the space available is tall and narrow, a tree with a pyramidal or spire-like crown is most suitable. A large, open space would be the perfect setting for a large, multi-stemmed Cedrus libani. However, this tree would not work well in a small area because of the massive sizes it is capable of achieving (Rushforth 1987).
There are a number of examples of the effective use of specimen or character trees. Several cultivars of Cupressus sempervirens, which have a columnar form, have been introduced into Italy where they line roadsides or accent large estates and castles. This tree has been so widely planted in the region of Tuscany that it has become an integral part of the character and charm of this beautiful and enchanting region (Fig 3.2). Similarly, the umbrella-like crown form of Pinus pinea has been used with great effectiveness to line streets and major arteries leading into Rome (author’s observation). In southern Brazil, the umbrella-like crown of Araucaria angustifolia, an indigenous species, appears in parks, golf courses and along roads and is an integral part of the landscape of this region (Ciesla 1986) (Fig 3.3).
Figure 3.2: Extensive plantings of columnar cultivars of Cupressus sempervirens in the Tuscany region of Italy has given the landscape a special character.
Shelter, screening and backcloth plantings
Shelter plantings are usually designed to protect adjoining areas from effects of wind or frost. The subjects they protect can range from other plants, to homes or greenhouses. Protection may take one of two forms, either overhead protection with overstory plants or side protection. In many open, arid regions of the world, where there is a frequent occurrence of high velocity, desiccating winds, various drought tolerant species of Juniperus are often used in combination with other broad-leaved trees as windbreak or shelterbelt plantings. Screening is similar to providing shelter, except that the objective is to shut out a particular intrusion such as an unsightly industrial facility. Plantings can also be used for visual screening or to trap dust and debris. While not particularly effective at screening out sounds, they can reduce the perceived sound because the source is no longer visible. The objective of backcloth planting is to display a plant or other item to best effect. Many attractive plants are best displayed when placed against a dark background. Conifers with dense, dark green foliage are best suited for this purpose (Rushforth 1987).
Figure 3.3: Planting of Araucaria angustifolia along a golf course, Curitiba, Brazil
Conifers can make very useful hedges. Ideal requirements for a hedge plant is that it will grow on a wide range of soils, be easily trimmed to the right size, be evergreen, make an effective barrier throughout the year, not need too much trimming and be fully hardy and pest and disease resistant. The hedge should also be quick to establish, which in practice competes with the need for not too frequent trimming. Many species of the family Cupressaceae are excellent materials for hedges (Rushforth 1987). In Kenya and other eastern and southern African countries, the Mexican cypress, Cupressus lusitanica, has been widely used for ornamental hedges and living fences around homes in rural settings designed to keep out free ranging livestock, wildlife and human intruders (author’s observation). Unfortunately, the viability of this species has been reduced by the recent introduction of a destructive insect, the cypress aphid (Ciesla 1991). In eastern United States, Tsuga canadensis is a popular hedge species (Rushforth 1987).
Christmas trees are an important seasonal commodity in countries where Christianity is the predominant religion and the birth of Jesus Christ is traditionally celebrated with a colourfully decorated tree in the home. Production and sale of Christmas trees is a multi-million dollar industry. Christmas trees are harvested from natural forests or trees grown in plantations established specifically for Christmas tree production. A number of commercial Christmas tree growers now offer customers the opportunity to select and cut their trees. In the United States, special permits may be obtained to harvest a Christmas tree in selected areas on public lands (National Forests or public lands administered by the Bureau of Land Management).
The tradition of a Christmas tree inside the home is generally associated with the Christian celebration of the birth of Jesus Christ. However, the tree used as a symbol of life, is a tradition much older than Christianity and is not exclusive to any one religion. Long before there was a Christmas celebration, Egyptians brought green palm branches into their homes on the day of the winter solstice as a symbol of life’s triumph over death. Romans adorned their homes with evergreens during Saturnalia, a winter festival in honour of Saturnus, their god of agriculture. Druid priests decorated oak trees with golden apples for their winter solstice celebrations. In Europe, during the Middle Ages, the Paradise tree, a conifer hung with red apples, was the symbol of the feast of Adam and Eve held on 24 December.
The first recorded reference to the Christmas tree dates back to the sixteenth century. In Strasbourg, France, families both rich and poor decorated fir trees, Abies alba, with coloured paper, fruits and sweets. At this time, the first retail sales of Christmas trees were also made, usually by older women, who would sell trees harvested from nearby forests. This tradition gradually spread throughout Europe.
By now a well-established European tradition, Christmas trees were introduced to the United States by German settlers and by Hessian mercenary soldiers who fought in the revolutionary war. In 1804, American soldiers stationed at Fort Dearborn, the present day location of the city of Chicago, cut trees from the surrounding forests and brought them to their barracks at Christmas. Charles Minnegrode first introduced the custom of decorating trees at Christmas in Williamsburg, Virginia in 1842. In 1851, Mark Carr hauled two ox-driven sleds loaded with trees harvested in the Catskill Mountains of New York State to the streets of New York City and opened the first retail lot for Christmas tree sales in the United States.
A German also introduced Christmas trees into Canada. In 1781, General Von Reidesel planted the first Christmas tree in Quebec. The custom spread during the Victorian period, although it was limited to the middle class. After 1920, the practice began to appear in large cities but in the rural areas of Canada, decorated trees did not become a familiar sight until the 1930s .
Many conifers are popular Christmas trees and preference varies with location. Local climatic conditions also affect the kind of trees that can be grown. The following sections highlight some of the more popular species, their desirable and undesirable characteristics (Hill 1989, Chapman and Wray 1979).
Characteristics that define a good Christmas tree include:
|1. Needle colour -||Christmas trees should have a rich, dark green or blue-green colour. Trees with thin or chlorotic (yellow) foliage are especially undesirable.|
|2. Needle retention -||Needles should remain on a tree for a long time after they are cut.|
|3. Needle sharpness -||Needles should be relatively soft and easy to handle.|
|4. Branch thickness -||Branches should be capable of supporting Christmas ornaments but not so thick that it is difficult to hang ornaments. Branches should be sufficiently durable to tolerate shipment.|
|5. Odour -||Foliage should have a pleasant fragrance and be free from pungent odours.|
|6. Overall form -||Trees should be conical in form and with sufficient foliage and branch density to appear full crowned.|
|7. Growth -||Growth should be sufficiently rapid to produce an attractive tree of saleable size in 7-10 years.|
The pleasing fragrance, colour, form and exceptionally long-needle retention after being cut, of the true firs make them highly prized Christmas trees both in Europe and North America (Tang-Shui Lui 1971).
Balsam fir, Abies balsamea, occurs naturally over a large area of eastern Canada and portions of north-eastern United States and is one of the most popular Christmas trees. It has a pleasant fragrance, a deep green needle colour and needles that are retained for a long time even in warm, dry rooms. In Canada, many balsam fir Christmas trees are still harvested from natural forests and shipped long distances to the United States, Mexico, Venezuela and Germany. Balsam fir is also a popular plantation grown Christmas tree. The southern balsam or Fraser fir, Abies fraseri, is closely related to A. balsamea and is endemic to the high mountain regions of the southern Appalachian Mountains (United States), and is also highly favoured as a Christmas tree.
Several western North American species of Abies are also popular Christmas trees. White fir, A concolor, is found in California and south-western United States where it is a popular regional Christmas tree. It has long needles (up to 4 cm) which are a grey-green colour. This tree has a relatively slow growth rate and trees cannot be harvested until they are at least 10 to 12 years old. Grand fir, A. grandis, is well known for its fragrant foliage and is widely grown in Christmas tree plantations where it is often sheared. Noble fir, A. procera, is considered a premier Christmas tree both in Europe and North America. This tree is native to north-western United States and adjoining portions of Canada and is widely planted in Christmas tree plantations. Noble fir tends to have an open crown, stout branches and luxurious, green needles. It is a popular tree for hanging large ornaments.
The Caucasian fir, Abies nordmanniana, of southern Europe is the principal species grown for Christmas trees in Denmark (Hansen et al. 1997). A. alba is also a popular Christmas tree in Denmark and other European countries.
The spruces are considered traditional Christmas trees, especially in Europe but have several undesirable characteristics, primarily poor needle retention. The foliage of several species also has pungent odours, which are unpleasant when brought into a home.
Norway spruce, Picea abies, was one of the first trees to be used as a Christmas tree in Europe and still remains a popular choice. This species has been introduced into the north-eastern parts of North America where it is widely planted for a number of purposes including Christmas trees. Its needles are dark green; the tree has a good natural form and requires little shearing. Its one serious weakness is poor needle retention.
White spruce, Picea glauca, a native of the North American boreal forest, has several desirable features including good form, slender branches and a grey-green needle colour. Although slow growing, it does well in plantations. Unfortunately, white spruce has poor needle retention and the foliage has an unpleasant odour when crushed.
Red spruce, P. rubens, another tree native to eastern North America has dark green foliage. It has good form but, like most spruces, suffers from poor needle retention. It is not widely grown because it generally takes 20-30 years to reach a saleable size. Black spruce, P. mariana, another component of the North American boreal forest, has very short needles. This tree is harvested for Christmas trees and often spray painted various colours for a speciality market. Colorado blue spruce, P. pungens, has an excellent blue-green needle colour and good form but has very sharp needles which makes this tree difficult to decorate.
Many species of pines are popular Christmas trees. They are particularly suitable for trees grown in plantations because of their relatively fast growth rates.
In the United States the Scots pine, Pinus sylvestris, is an extremely popular species. This native Eurasian pine was introduced into North America as a potential timber species with disappointing results. However, this tree responds well to shearing which results in a Christmas tree with a dense, conical crown and can be grown in cold climates. Because of its extensive natural range, there is considerable variation in form, growth rates and needle colour of this species, and provenance is an important criteria in selecting seedlings for Christmas tree production. Some forms are subject to fall yellowing which reduces their marketability as a Christmas tree. Ironically, this tree, which is so popular in North America, is not used as a Christmas tree in Europe.
Pinus nigra, another European species, is grown on a small-scale in the United States for Christmas trees; however, there is limited demand for this species. Needles are a rich green colour and growth rate is rapid that trees must be sheared in order to ensure good form. Undesirable characteristics include needles that are long and stiff and the presence of thick, stiff branches, which makes handling difficult.
Eastern white pine, Pinus strobus, is a highly favoured tree in eastern North America. It has needles with a uniform bluish-green colour, which remain on the tree for a long time after cutting. This species also has a rapid growth rate and must be sheared to ensure good form and foliage density. Unfortunately, it has somewhat brittle branches and does not lend itself well to long-distance shipping.
Radiata pine, Pinus radiata, is the most widely planted of all pines and has several characteristics that make it a desirable Christmas tree. It is fast growing and has rich dark-green foliage. It is not suitable for planting in cold climates, dry climates or climates with a summer rainfall pattern. Virginia pine, Pinus virginiana, is a tree native to portions of south-eastern United States. This tree has become a popular Christmas tree locally because it responds well to shearing. Other pines, which have been used as Christmas trees (primarily in the United States), include Pinus resinosa, P. thunbergiana, P. banksiana, P. rigida, P. taeda and P. echinata.
Douglas fir is a popular Christmas tree, especially in western North America where it is native. It has all of the qualities desired in a Christmas tree. Needles are about 1 cm long and needle colour varies from grey-green or blue-green to deep green. Needle retention is good in warm rooms. Response to shearing is good, resulting in a more symmetrical tree with dense foliage. Its growth rate is relatively slow and more than ten years are required to produce a saleable tree. Douglas fir is the most popular Christmas tree in north-western United States and is gaining popularity in other markets as well.
Eastern red cedar, Juniperus virginiana, is a locally important species in south-eastern United States where it is grown in plantations. Further north, the foliage tends to take on a purplish cast during winter, which reduces its desirability for Christmas tree use. Cupressus arizonica, a species with blue-green foliage, is becoming a popular Christmas tree in south-eastern United States.
In southern Brazil, Araucaria angustifolia is a popular Christmas
tree (Reitz et al. 1979). A. columnaris, a species native
to New Caledonia (frequently referred to as Norfolk Island pine, A.
heterophylla) is widely planted as a Christmas tree in the Hawaiian
Islands (USA) and has been exported to the Pacific coastal regions of the
United States as a novelty Christmas tree (Little and Skolmen 1989).
The United States is a major producer of Christmas trees with an annual harvest of about 35 million trees during 1993-96. Most trees are harvested for domestic use. Christmas trees are grown in all 50 States on a total area of about 400 000 ha. The principal Christmas tree producing-states are Oregon, Michigan, Wisconsin, Pennsylvania, California and North Carolina. Most Christmas trees are produced in plantations although some are still harvested from natural forests. There are about 15 000 Christmas tree growers in the United States and over 100 000 people are employed either full time or part time in this industry .
Canada is another major Christmas tree producer with an annual production
of about 4 million trees valued at US$38-45 million. Approximately 50 percent
of Canada’s Christmas trees are exported, with the United States being
the largest market. In 1994, some 2 million of Canada’s total export of
2 118 500 trees were exported to the United States (Table 3.2). Other countries
receiving large numbers of Canadian Christmas trees were Panama, the Netherlands
Antilles, Venezuela and Bermuda. Unlike the United States, most Canadian
Christmas trees are harvested from natural forests (primarily Abies
balsamea) but the number of Christmas tree plantations is on the increase.
The Province of Quebec is Canada’s biggest producer of Christmas trees
followed by Ontario, Nova Scotia, New Brunswick and British Columbia (Fig
3.4). Canada also imports about US$3 million in Christmas trees annually
from the United States (National Forestry Database Program 1996).
Christmas tree production, exports and imports
Source: National Forestry Program DataBase (1996)
In Europe, Christmas trees were first produced while thinning undergrowth. Although this may still be the case in a few occasions, the bulk of the Christmas tree production is produced in specialised plantations. Denmark is the leading producer of Christmas trees in Europe. In 1994, the Danish
Christmas industry had an income of approximately US$110 million (green
foliage and trees) accounting for about one-third of the country’s total
forestry income (Hansen et al. 1997). In the Århus Forest
District, for example, 36 percent of total receipts were derived from the
sale of non-wood forest products, including Christmas trees. In Denmark,
Christmas trees are almost exclusively produced on very intensively managed
plantations (Munk Plum P. 1998, personal communication). Germany is also
a major Christmas tree producer. Hartwig (1977) estimated the share of
decorative greens and Christmas trees together at 0.4 percent of the total
value of receipts from sales of forest products.
Figure 3.4: Christmas tree production in Canada by Province – 1994.
Mexico has recently become a major market for Christmas trees. Over
a two-year period, Mexican Christmas tree imports virtually doubled (Table
3.3) and by 1993, Mexico imported over US$6 million in trees, 95 percent
of which came from the United States, primarily the Pacific north-western
States (Oregon and Washington). The remainder is imported from Canada.
Noble fir, Abies procera, accounted for 60 percent of the sales
because of its longer needle retention. Pseudotsuga menziesii and
Abies balsamea were also important. Some vendors attempted to market
Pinus sylvestris, but Mexican consumers, because of its sharp needles,
did not favour this species. Domestic Christmas trees are available from
the states of Mexico, Michoacan, Durango and Chihuahua. However, the most
significant problem facing this sector is the scarcity of specialized Christmas
tree growers. A few Christmas tree plantations exist and their numbers
are growing, especially in the states of Puebla and Mexico. Statistics
on Christmas tree production and consumption in Mexico do not exist at
present (USDA 1995).
Mexican imports of Christmas trees, 1991-93
Source: USDA (1995)
Bonsai is a technique for retaining the essential growth form of a tree but reducing it to pocket size. Many species of conifers are used in bonsai, which can be cultivated either outdoors or indoors (Rushforth 1987).
The word "bonsai" has its origins in China where it was derived from two words, bon, meaning a tray or pot and sai, meaning a plant (Stowell 1966). Bonsai literally means a plant or tree growing in a tray or pot. The practice of growing trees in pots can be traced to Egypt about 4000 years ago. The purpose of planting trees in pots at that time was for mobility. The Greeks, Babylonians, Persians and Hindus subsequently adopted this practice.
The first records of growing small trees in pots are from China during the Tsin era (third century BC). On the tomb of Zhang Huai, the second son of the empress Tang Wu Zeitan, there is a figure of a woman carrying a bonsai in both hands. Later, during the Tang dynasty (618-907 AD) and the Song dynasty, public records refer to a man who "had learned the art of creating the illusion of immensity enclosed within a small space and all this contained within a single pot." During this same period, Buddhist monks are said to have carried the p’en-tsai (trees taken from natural surroundings and replanted, just as they were, in ornamental pots) throughout the Far East.
Bonsai, as it is known today, originated in Japan. The first references
to bonsai began to appear in Japan between the twelfth and mid fourteenth
centuries. There is a famous scroll of the Buddhist monk, Honen, which
is decorated with bonsai and dates roughly from the twelfth century. The
period of Edo (1615-1867) was a period of growth in interest of colourful
trees grown in trays. The bonkei were landscapes on trays and bonsai
trees grown in pots. The well-to-do classes in Japan gradually developed
an attachment for bonsai and the trees they succeeded in growing took pride
of place in their homes. Soon the cultivation of bonsai as a hobby spread
through all of Japan’s social strata, with the last to adopt the practice
being the poorer classes. Today, bonsai culture is practised throughout
all of Japan.
There is an old Japanese tale about a sage who explained his smooth and youthful features by his devotion to bonsai. When he contemplated his work, he could not grow old because "while flowers may fade in winter, in his home they were always in bloom".
Bonsai is an inward image, a symbol of eternity. It is said to abolish time and reflects the harmony between man and nature and heaven and earth (Samson and Samson 1986).
Bonsai first began to appear in Europe in the fourteenth century when it was introduced by travellers to the Far East but was largely forgotten by the eighteenth century. This art form enjoyed a renaissance in Europe during the nineteenth century when several serious essays appeared on means employed by the Japanese to develop dwarf trees (Samson and Samson 1986).
The cultivation of bonsai was first brought to North America by Japanese immigrants, many of who settled along the Pacific Coast (Stowell 1966).
Bonsai is a three dimensional, living form of art. Through special techniques and the application of the principles of design, plants are developed into objets d’art. Bonsai is something of nature evoked in miniature and is meant to communicate the idea of a windswept tree clinging to a rocky crag; an ancient rugged pine that has survived years of wind, sun and rain or a group of such trees or of some lovely distant landscape. Bonsai should never appear grotesque or unnaturally distorted; it should simply reproduce nature in miniature. Bonsai differs from ordinary potted plants in that woody or somewhat woody plants are always used. The growth is trained and controlled so as to produce a miniature tree. Bonsai is an aesthetic use of horticultural material, an abstraction of nature on a reduced scale (Stowell 1966).
In every bonsai, one should find the shape of the triangle (Fig 3.5). Bonsai joins heaven and earth and becomes a concrete allegory by leading humans along the pathway of spiritual values. Four main groups of bonsai are recognized (Samson and Samson 1986).
Figure 3.5: A Juniperus
procumbens bonsai in the shakan style (Photo taken at the Bonsai Nursery,
1. Group 1 - A single trunk
|Chokkan -||The formal upright style where the tree grows upward toward the sky.|
|Shakan -||The trunk bends and may do so to the extent of being semi-cascade.|
|Kengai -||A cascade style, plunging downwards.|
|Bankhan -||The trunk winds around itself like a twisted cord.|
A number of sub-styles are derived from these four basic styles.
2. Group 2 - Multiple stems from a single root
|Sôkan -||A double trunk.|
|Kabudachi -||Multiple trunks grouped around a single root.|
|Kôrabuki -||Multi-trunked style.|
|Ikadabuki -||Straight line style; a horizontal trunk forms the stump.|
|Netsunagari -||Sinuous style with several trunks growing from a single sinuous root.|
3. Group 3 - Multiple trunks or Group plantings
|Sôju -||Twin trunks.|
|Sambon-Yôse -||Three trunks.|
|Gohon -Yôse -||Five trunks.|
|Nanahon - Yôse||Seven trunks.|
|Kyûhon - Yôse -||Nine trunks.|
|Yôse - Ue -||More than nine trunks.|
|Yomayori or Yomayose -||A natural grouping.|
|Tsukami - Yôse -||Clustered group style - multiple trunks springing up from the same place.|
4. Group 4 - These are not bonsai in the strict sense but are miniature landscapes, grass plantations and seasonal plants.
Bonsai can be propagated from seeds or seedlings, cutting, layering or grafting. Techniques have evolved over many years, which allow the grower to change the height and direction of the tree’s growth and in some cases to dwarf the foliage of the tree. Trees selected for bonsai are kept small by pruning of new growth, root pruning and limiting growing space. While there are certain classic or traditional forms that can be followed, the rule of thumb for a personal bonsai is "if you like the way it looks, it’s a good bonsai".
A popular misconception about bonsai is that the trees are always old. In actuality bonsai can be any age. Years are not a factor that relates to quality in bonsai. There are techniques in the development of bonsai that can give a young tree a much older appearance (Stowell 1966).
Both broad-leafed trees and conifers are used in bonsai. Because bonsai should look like mature trees in miniature, commonly used species typically have small leaves or needles so that the trunk, branches, twigs, leaves and roots will be in scale in overall composition (Stowell 1966).
A large number of conifers of the families Cupressaceae and Pinaceae
are good candidates for bonsai (Table 3.4). Initially this art form was
confined to Asian species. However, as it became popular with western cultures,
it was learned that a number of European and North American species also
lent themselves to this form of cultivation. Members of the genus Juniperus
are especially popular for bonsai because they are relatively easy to care
for and are especially popular with beginners.
Bonsai exist in nature. They are commonly seen on high mountains or in rocky places were there is little or no soil. Other factors, which may cause natural bonsai, are chronic drought, wind, avalanches or heavy browsing. The first bonsai trees were taken from the natural environment. To remove a tree from its natural habitat, part of the roots were cut over a period of two to three years, usually in the spring. The removal of naturally occurring bonsai was an art form in itself. However, this practice is forbidden today in many places (Samson and Samson 1986).
Today, bonsai are sold and cultivated in many parts of the world. Many large cities have at least one organization for bonsai enthusiasts (Stowell 1966). In addition to Japan, bonsai clubs are found in North America, most western European countries, Australia, Brazil, New Zealand and South Africa.
Bonsai can be purchased in either speciality shops or sometimes in stores,
which sell gardening supplies. In some countries, bonsai can be purchased
in street markets. A small, young bonsai, in a simple pot, can sell for
as little as US$ 20. Larger, more elaborate bonsai can sell for US$1 000
and up. Some dealers sell 6 to 8 cm starter plants for approximately US$
Some conifers used for bonsai
Sources: Menage 1975, Samson and Samson 1986, Stowell 1966, Yashiroda 1960, Bonsai Nursery Inc., Denver, Colorado, USA.
Topiary is the creation of sculpture out of a living, growing plant. Species used as a basis of this art form need to be able to withstand repeated clipping. Ideally, they are tough and hardy evergreen plants. Several conifers are used in topiary. One especially popular species is Taxus baccata, which is particularly desirable because it is slow growing and requires less trimming to achieve the desired shape.
In topiary, plants can be trimmed to make a variety of forms, ranging from pocket battleships, animals or regular cones suitable for very formal gardens (Rushforth 1987).
Figure 3.6: Bonsai, Pinus parviflora, for sale in a street market in Hefei, Anhui Province, China.
Some conifers can be used as houseplants and some species survive indoor conditions quite well. This is the only practical means of growing tropical conifers in temperate climates although not all conifers will tolerate indoor conditions well.
The Norfolk Island pine, Araucaria heterophylla, is a tree widely used for indoor culture. Other species of Araucaria can also be grown indoors. The cultivar "Goldcrest" of Cupressus macrocarpa is often sold as a houseplant as are juvenile forms of several species of Pinus (e.g. P. canariensis or P. pinea) (Rushforth 1987).
1/. According to Little and Skolmen (1989), most of the Araucaria planted in the Hawaiian Islands is actually Araucariacolumnaris, a closely related species indigenous to New Caledonia.
2/. Information in this section was obtained from the National Christmas Tree Association (NCTA) of the USA via the World Wide Web at: http://christree.org/dir/US.IA.SweaCity.htm.
3/. The Christmas tree comes to Canada, at http:// www.chin.gc.ca/christmas/sap intro.htm
4/. Data obtained from the National Christmas Tree Association (NCTA) via the World Wide Web.
5/. Data obtained from the Danish Forestry Research Institute, Copenhagen at http://www.fsl.dk/.