The fruits of many broad-leaved temperate hardwoods provide a variety of beneficial products ranging from edible fruits to industrial oils. Many temperate broad-leaved trees yield fruits that are important agricultural crops, worldwide, and are grown commercially in orchards. Examples include pome fruits such as apple (Malus pumila); pear (Pyrus domestica); stone fruits, such as cherries, apricots, peaches and almonds; various species of Prunus); olives (Olea europea); and figs (Ficus spp.). Since these fruits are considered to be agricultural rather than forest crops, they will not be discussed in depth in this chapter. Emphasis is placed on those products that are still gathered, at least to some degree, in natural or planted forests.
Tung oil or "China wood oil" is a quick-drying vegetable oil extracted from the seeds of the tung tree (Aleurites fordii, family Euphorbiaceae), a tree native to central and western China. Similar oils are produced from related species such as A. montana, native to southwestern China, and several tropical species of Aleurites [Duke, 1983; Panshin et al., 1950]. This tree has been widely planted in areas outside its natural range [Duke, 1983].
Tung oil has been used by the Chinese for centuries to protect and beautify timber and regarded as the ultimate oil finish for enhancing the natural beauty and grain of timber. Its properties were not appreciated outside of China until about 1869 when the first shipment reached the United States. This is the year that marks the beginning of world trade in this important industrial commodity [Panshin et al., 1950]. During the Second World War, the Chinese used tung oil as a motor fuel, but it tended to cause gumming of engines. However, when the oil was mixed with gasoline, it worked well and served to extend gasoline, which was in short supply [Duke, 1983].
The importance of tung oil in the paint and varnish industries and the uncertainty of the supply and quality of this product from China led to the establishment of experimental planting of tung trees in the United States. The first successful plantings of tung seeds was made in 1905 by the Division of Foreign Plant Introduction of USDA in Chico, California. The seedlings were used for test plantings across the southeastern and Pacific Coast states. By the 1950s, there were more than 30 000 ha of tung plantations. Most of them were established in Mississippi, followed closely by Florida [Panshin et al., 1950]. However, many tung oil plantations were either destroyed or severely damage when hurricane Camille struck Mississippi in 1969 [author’s observation]. The establishment of a tung oil industry in the southeastern United States made a significant contribution to the diversity of a regional agricultural system that was formerly based almost entirely on cotton production; helped to restore wasteland and resolve severe soil erosion problems; and led to the establishment of a regional paint and varnish industry [Panshin et al., 1950].
The fruit contains from 14 to 20 percent oil, the kernel 53 to 60 percent and the nut has an oil content of 30 to 40 percent. The components are: elaeo strearic oil (75-80%), oleic oil (15%), palmitic (about 4%) and stearic acids (about 1%). Tannins, phytosterols and saponin are also reported [Duke, 1983].
Figure 7.1a Tung oil with fruits.
Figure 7.1b A wood finish made from tung oil on a table finished with this product.
Tung oil is used in the manufacture of lacquer, varnishes, paints, linoleum, oilcloth, resins, synthetic leather, felt-based floor coverings, greases, brake linings and in cleaning and polishing compounds (Figure 7.1). Tung oil products are used to coat containers for food, beverages and medicines. They are also used for insulating wires and other metallic surfaces such as radios, radar, telephone and other communications hardware [Duke, 1983].
Tung trees usually begin to bear fruit during the third year after planting and are in commercial production by the fourth or fifth year. They reach maximum production in 10-12 years. The yield of mature trees ranges between 4.5 t/ha and 5 t/ha. The average productive life of a tree in the United States is approximately 30 years. Fruits mature and drop to the ground in late September to early November, at which time they contain about 60 percent moisture. Fruits are left on the ground for three to four weeks until the hulls are dry and the moisture content has dropped below 30 percent. The fruits are gathered by hand into baskets or sacks. An average picker can gather 60-80 bushels of fruit per day, depending on conditions in the plantation. Fruits are usually sacked, placed in the crotch of a tree and allowed to dry for another two to three weeks. Additional drying may be done at the mill because wet fruits contain less oil on a percentage basis and prices would be lower [Duke, 1983].
In 1969, world production was 107 000 t, and during the following year it increased to 143 000 t. Production for the 1980s was projected to average 199 000 t/a. Prices for tung oil depend on production, price supports and industrial demands but have recently averaged US$ 0.28/kg wholesale and US$ 0.34/kg for imports to Europe. Growers receive about US$ 51/t of fruit with 18.5 percent oil content and US$ 63/t of fruit with 22 percent oil content.
Major producers of tung oil are Argentina, China, Paraguay and the United States. The largest consumption of tung oil is in the manufacture of paint and varnish [Duke, 1983].
The species carob (Ceratonia siliqua L.) is a slow-growing evergreen tree with rich, glossy foliage. Carob is native to the Eastern Mediterranean area. The tree blooms in the autumn and carries the young fruit to the end of the next summer. Its fruits/pods are rich in protein and sugar and are used in chocolate and pastry manufacturing and for photographic emulsion. Carob pods are also used as nutritious animal feed, whereas the herbaceous ground cover makes good pasture [Moussouris and Regato, 1999; Russel and Smith, 1950].
Ceratonia siliqua L. bears fruit at the age of six to eight years. At an average, a tree then yields 200-250 lb/a of fruit. The abundance of fruit is greater every second year. Also the seeds are edible and produce a protein-rich flour that contains no starch or sugar and is ideal for diabetics. The endosperm is extracted from the seed to produce galactomannan, which forms locust bean gum, a food additive. The pod is used for high-energy livestock feed and in the production of cocoa products and syrups. These are used as a substitute for cocoa and as a food (also known as algarroba, St. John's bread, and locust bean gum) [Goor and Barney].[32]
Carob is a typical Mediterranean tree species that can be found in the coastal areas. In Lebanon for example it can be found up to 800 m, where it represents an important source of additional revenue to many local farmers. Both wild and cultivated populations can be found, often close to each other or even mixed. The wild populations can be found under very different environmental conditions, showing different growth characteristics. The fruits from carob are harvested in September. In Portugal and Spain, most carob plantings are located on steep, rock sites, unsuitable for other agricultural crops and require hand harvesting. Harvesting represents 30-35 percent of the total production cost. Harvested carob pods are first “kibbled”, a coarse grinding process that separates the pod from the unbroken seeds.
In large parts of its distribution range, Ceratonia siliqua is under increasing pressure, mainly because of urbanization and conversion of areas to agricultural land. This degradation of carob populations seems to be symptomatic of the decline of the whole natural vegetation of the coastal regions [Breugel and Stephan, 1999].
Figure 7.2 Pods of the carob tree (Ceratonia siliqua) near Limassol, Cyprus.
Carob production is presently centered in Portugal and Spain, which have about 100 000 ha of carob trees and process about half of the world’s commercial supply. World production is presently about 315 000 tonnes per year and the main producers are Spain (42%), Italy (16%), Portugal (10%), Morocco (8%), Greece (6.5%), Cyprus (5.5%) and Turkey (4.8%).
Carob has been introduced to temperate regions in Central America and also to Australia. More information on Carob is also described in the Non Wood Forest Products Series no. 6: Gums, Resins and Latexes of Plant Origin (FAO, 1995).
The genus Prosopis (family Leguminosae) consists of about 45 species of small- to medium-sized trees or shrubs. Most occur in the Western Hemisphere in semi-arid temperate regions, but three species are found in Asia and Africa [Little, 1979]. The seed pods of several species of Prosopis are edible and used as food for human consumption or as a livestock feed.
In the desert regions of Arizona and California, Prosopis pods were an important food for indigenous tribes. Large trees with a 40-60 cm basal diameter, growing in riparian zones in this region, can yield up to 40 kg of pods per tree. The pods contain approximately 13 percent protein and 35 percent sugar. They were ground into flour with stone mortars, and the hard seeds were often discarded. The pods of Argentinian species of Prosopis were used in a similar manner and research is currently under way in Peru to develop industrial processes that will produce products from the pods of these trees that will appeal to contemporary human societies. In the United States, some cottage industries have arisen that make jelly and flour from Prosopis pods. The pods have a strong mocha-cinnamon aroma, and a potential exists for producing special baking flour for muffins and fruitcakes. In India, the green pods of Prosopis cineraria are a popular human food, and in some locations the crop price in the marketplace is US$2.00/kg, more than half the average daily wage [Felker, 1998].
A current limitation to widespread use of Prosopis pods for human food in the United States is the high cost of manual harvest in natural forests. If trees could be grown in straight rows in orchards and pod harvesting could be mechanized, an industry based on production for human use could be developed [Felker, 1998].
In the arid regions of northern Chile (Regions I-III), Prosopis spp., principally P. tamarugo (common name tamarugo) and P. chilensis (common name algarrobo), cover an area of approximately 20 000 ha. The fruits of these trees are an important and nutritious source of fodder for livestock, including cattle, sheep and goats [Garfias Salinas et al., 1995]. In Argentina, the fruits of Prosopis spp. are used as a cattle feed and in the production of a fermented beverage [Résico, 1995].
Approximately 80 species of Sorbus (family Rosaceae) are found in Asia, Europe and North America. Commonly known as rowans, mountain ashes, whitebeams and service trees, the fruits of this group of trees have been used for a wide variety of purposes [Hora, 1981].
Several species of Sorbus, including the European mountain ash (Sorbus aucuparia), produce clusters of bright-red berry-like fruits (Figure 7.3). The fruit of this species has been used for a variety of traditional foods. Several recipes exist for producing jams and jellies that are said to be excellent accompaniments to cold game or wild fowl. A wholesome cider can be made from the fruit. In northern Europe, the fruits were dried for flour that yielded a strong spirit when fermented. The Welsh once brewed what was said to be a delicious ale from the fruits of rowan but, unfortunately, this recipe has been lost [Ciesla, 1990; Grieve, 1931].
Mountain ash fruits are still gathered in a number of European and Near Eastern countries including Armenia (Ter-Ghazaryan and Ter-Ghazaran, 1998]; Belarus, where approximately 1092 t are harvested annually [Ollikainen, 1998]; Lithuania, 12 t are harvested annually [Rutkauska, 1998]; and Poland, with an annual harvest of 670 t [Kalinowski, 1998]. They have a high tannin content and should not be eaten fresh, but be left ripening after picking to develop a pleasing sweet-sour taste similar to grapes. They may also be eaten after being sun dried for 15-20 days. The berries are also a source of malic acid, which is used as a flavouring and in wine [Bounous and Peano, 1990].
The fruit of the American mountain ash (S. americana) has a sharp flavour, is rich in vitamin C and has been used in a variety of herbal medicines [Ciesla, 1990].
The service tree (Sorbus domestica), a tree native to southern Europe, north Africa and the Near East, produces brownish-coloured pear-shaped fruits that are sour but edible when overripe or after they have been exposed to frost [Hora, 1981].
The genus Diospyros (family Ebenaceae) is primarily tropical and consists of about 485 species. However, a number of species extend into the temperate forests, primarily in China and Japan; and two species; D. texana and D. virginiana, occur in North America [Little, 1979]. Several temperate species produce a sub-globose berry that is orange coloured and tinged with purple when ripe and are edible [Harlow and Harrar, 1950]. The kaki or Japanese persimmon (D. kaki) is widely grown in orchards both in China and Japan for its fruit. In Japan, it is regarded as the country’s national fruit [Hora, 1981].
The fruits of the common persimmon (D. virginiana), a small to medium tree of the eastern hardwood forests of the United States, remain on trees after the foliage has been shed in autumn. In the southeastern United States, these fruits are commonly gathered after a frost has occurred. Persimmon pie and jelly are traditional local food of this region [author’s observation].
The various species of hawthorn or thorn apple (Crateagus spp., family Roseaceae) produce edible fruits with a taste similar to that of a tart crab apple. Mayhaws (C. aestivalis, C. opaca and C. rufula) are indigenous to the southeastern United States and produce early ripening, yellow to bright-red fruits with a pleasant flavour. This small tree, which is usually found in low-lying wet areas, may be one of the last fruit-bearing trees indigenous to the United States that has not yet been widely commercialized [Payne and Krewer, 1990; Thomas and Schumann, 1992].
Mayhaws are used to make jellies, marmalades, preserves, salad dressings, wines, syrups, sauces and desserts. Traditional recipes for making these products have been in existence for nearly 100 years. However, there has been some recent renewed interest in this traditional fruit of the southeastern United States, especially in Alabama, Georgia, Louisiana and Mississippi. In 1991, a family-run mayhaw preserve company based in Louisiana purchased about 45 000 kg of mayhaw berries and produced 23 000 cases of mayhaw jelly [Thomas and Schumann, 1992]. Fresh mayhaw fruits currently sell for US$ 2.75-4.40/kg and the jelly for US$ 18.00/litre. There is some interest in the commercialization of this fruit, and one source predicts that the tree may be found in commercial orchards within the next decade. Several cultivars have been developed for use in orchards [Payne and Krewer, 1990]. The fruits of Crateagus cuneta are used for the treatment of stomach complaints in China [Hora, 1981].
Sea buckthorn (Hippophae rhamnoides L.) is a fast-growing deciduous shrub tree widely distributed in temperate regions that produces valuable fruits for diet and raw material for the pharmaceutical industry. Its fruits contain a wide range of vitamins such as provitamin A, vitamins B (tiamin), B2 (riboflavin), E (okoferol), K (phyllokinon), P, PP and others.
It is native to Europe and Asia and has been known and used by humans for centuries. It is mentioned in the writings of ancient Greek scholars such as Dioscorid and Therophast. In ancient Greece, sea buckthorn was known as a remedy for horses. Leaves and young branches were added to the fodder. This resulted in rapid weight gain and a shiny coat for the horse. This, in fact, gave the name to the plant in Latin hippo = horse, phaos = to shine [Rongsen, 1992].
The interest in sea buckthorn growing has increased due to the its various uses and has become an important subject for domestication in many countries. In the last years, the shrub tree, which previously grew exclusively in home gardens, has been introduced into plantations. The sea buckthorn industry has been thriving in Russia since the 1940s when scientists there began investigating the biologically active substances found in the fruit, leaves and bark. The first Russian factory for sea-buckthorn product development was located in Bisk. These products were used in the diet of Russian cosmonauts and as a cream for protection from cosmic radiation. The Chinese experience with sea-buckthorn fruit production is more recent, although traditional uses date back many centuries. Research and plantation establishments were initiated in the 1980s. Since 1982 over 300 000 ha of sea buckthorn have been planted in China. In addition, 150 processing factories have been established, producing over 200 products. The sea buckthorn-based sport drinks "Shawikang" and "Jianibao" were designated as the official drink for Chinese athletes attending the Seoul Olympic Games [Rongsen, 1992].
The potential of sea buckthorn in North American markets still remains untapped.
Sea buckthorn is easy to propagate by seed or cuttings. It can grow in arid to very wet conditions and tolerates cold winters. Though it prefers sandy and neutral soil, sea buckthorn survives in soils with pH values from 5 to 9 [Schroeder, 1995] and tolerates seawater flooding. It is a pioneer species and often the first woody species colonizing open areas such as abandoned farmland, wasteland and rocky islands. Sea buckthorn prefers full sunlight, does not tolerate shade and suffers even under sparse tree cover. Like other members of the Elaeagnaceae family, sea buckthorn is also a nitrogen fixer.
Since the discovery of the nutritional value of sea buckthorn, hundreds of sea-buckthorn products made from the berries, oil, leaves, bark and the extracts from them have been developed. In Europe sea-buckthorn juice, jellies, liquors, candy, vitamin C tablets and ice cream are readily available [Bernáth and Földesi, 1992; Wolf and Wegert, 1993].
At present, the largest producers and consumers of sea-buckthorn products are China, Russia, and Mongolia. They all have large-scale processing facilities. Processed products include: oil, juice, alcoholic beverages, candies, ice cream, tea, jam, biscuits, vitamin C tablets, food colours, medicines, cosmetics and shampoos [Iirkina and Shishkina, 1976; Wu, 1991].
Oils and oil extracts are the most important sea-buckthorn products produced in Russia. These oils are processed and sold as essential oils for numerous medicinal and therapeutic uses. Fruit drinks were among the earliest sea-buckthorn products developed in China. These drinks have had strong market demand and excellent consumer acceptance. They have rapidly gained a reputation both as a satisfying drink and as a nutritional beverage that enhances stamina and vitality.
Cosmetic applications of sea buckthorn are well known in Russia and China. In Russia, sea-buckthorn berries are often used in homemade cosmetics. Recipes for moisturizing lotions, dandruff control and hair-loss prevention are widely known and used in Russia [Pashina, 1993]. Sea-buckthorn oils contain high concentrations of palmitoleic acid. This rare fatty acid is a component of skin fat and can support cell tissue and wound healing. It is generally accepted in the cosmetic industry that sea-buckthorn oils have unique anti-ageing properties and, as a result, are becoming an important component of many facial creams manufactured in Asia and Europe. In addition, the UV-spectrum of the oil shows a moderate absorption in the UV-B range which makes sea-buckthorn derived products attractive for sun-care cosmetics [Quirin and Gerard, 1994].
Black elder, Sambucus nigra (family Caprifoliaceae), is a fast-growing deciduous shrub native to Europe, western Asia and North Africa. Numerous species of elder or elderberry grow in Europe and North America.[33]
Elderberries have long been used as food, particularly in dried form. Elderberry wine, pie, and lemonade are some of the popular ways to prepare this plant as food. Elder wine is prepared of dried English elder berries. These are preferred to French and other Continental elder berries since they have a more pleasant odour and flavour.
The berries are also used for medicinal purposes. Only those with blue/black berries are medicinal for diseases such as bronchitis, common cold, sore throat, infection and influenza. A tea made of the dried berries is said to be a good remedy for colic and diarrhoea. In the ‘Anatomy of the elder’, it is stated that the berries of the elder are useful in epilepsy. Further, they were held by our forefathers to be helpful in rheumatism and erysipelas.[34]
Mespilus germanicus (family Rosaceae) is a small, deciduous tree native to southeast Europe and Central Asia and is naturalized in the United Kingdom, as well as in other parts of northern Europe. The medlar tree, which is its common name, blooms and bears fruit when very young. Its fruits are edible and can be made into preserve or are more commonly allowed to rot ('blet') for a few weeks. This latter process is known as bletting and is similar to the riping process of American persimmon. The bletted fruit has flesh with the consistency and taste of apple butter.[35]
Rubus occidentalis L. (family Rosaceae) is native to many parts of Europe. Its fruits, called raspberries, are fragrant, subacid and cooling. They contain crystallizable fruit sugar, a fragrant volatile oil, pectin, citric and malic acids, mineral salts, colouring matter and water. By adding sugar and white wine, the juice of the ripe fruit is used to make an acid syrup called raspberry vinegar. When adding water, it serves as a cooling drink in summer, which also can be used to boost fever as well as for sore throats. A wine can also be brewed from the fermented juice of ripe raspberries. This wine is antiscrofulous, and raspberry syrup dissolves the tartar of the teeth. The fruit is also used for dyeing purposes.[36]
The fruits of several species of dogwoods (Cornus spp.) are rich in vitamin C and the berries are added to wines and liqueurs in northern Italy as flavourings [Bounous and Peano, 1990].
A tree known as strawberry tree (Arbutus unendo), which is indigenous to the Mediterranean region, produces a fruit that is moderately sweet, high in vitamin C and may be eaten ripe or as a jelly (Figure 7.4). It is also used in the production of wines and liqueurs on the islands of Sardinia (Italy) and Corsica (France) [Bounous and Peano, 1990). In Portugal, this fruit is a constituent of medronho, a strong alcoholic spirit with a unique flavour [Hora, 1981].
The North American mulberry (Morus rubra) produces reddish to purplish coloured fruits that readily drop from branches when they are ripe. The fallen fruits are juicy and sweet and were collected to make jams and jellies. They were an important food source for indigenous tribes and early European colonists in North America [Hora, 1981]. Mulberries are also gathered from wild trees in parts of Pakistan and are dried and sold in markets [author’s observation].
The pods and fruits of several species of Gleditsia (family Leguminoseae) are used for a variety of purposes. The Caspian locust (G. caspica and G. japonica), indigenous to Japan, and G. macracantha, indigenous to China, are used in the manufacture of soap. The pods of G. macracantha are used in tanning. The pods of the North American G. triacanthos can be fermented into a beer or fed to livestock [Hora, 1981].
Blue honeysuckle (Lonicera L. subsect. Caerulea Rehd., family Caprifoliacae) grows wild in Russia, China, Japan, Canada and in the United States. Its fruits are characterized by a sour-sweet taste and very early maturity, which occurs in June. In Russia, blue honeysuckle is a popular berry crop, which is used commercially and by amateur horticulturists [Plekhanova, 1998; Plekanova and Streltsyna, 1998].[37]
Figure 7.5a: Fruits of: Black raspberry (Rubus occidentalis).
Figure 7.5b: Fruits of: Mulberry (Morus rubra).
Figure 7.5c: Fruits of: Dogwood (Cornus spp.).
Figure 7.5d: Fruits of: Persimmon (Diospyros spp.).
Figure 7.5e: Fruits of: Hawthorn (Crateagus spp).
Figure 7.5f: Fruits of: Sea Buckthorn (Hippophae rhamnoides).
|
[32] Source: Spring tree
carob (http://www.springtree.com/carob.html) Ecology & Evolutionary Biology
Conservatory (http://florawww.eeb.uconn.edu/acc_num/199000057.html) Carob
(http://www.humorscope.com/herbs/carob.html) [33] Source: Elderberry (http://www.gnc.com/wellness/natpharm/Herb/Elderberry.htm) [34] Source: Sambucus (http://www.healthlink.com.au/nat_lib/htm-data/htm-herb/bhp727.htm) Sambucus nigra (http://www.msue.msu.edu/msue/imp/modop/00001315.html) [35] Source: Plant of the week (http://www.bl.rhbnc.ac.uk/plant/medlar.html) The Medieval medlar (http://www.ars-grin.gov/ars/PacWest/Corvallis/ncgr/cool/medlar.html) [36] Source: Raspberry (http://www.botanical.com/botanical/mgmh/r/raspbe05.html#cul) [37] Source: Encyclopedia (http://www.encyclopedia.com/articles/06017.html) |
