A wide range of beneficial non-wood products are derived from organisms that are closely associated with broad-leaved temperate trees, either as parasites, symbionts or saprophytes. These include edible mushrooms, products from insects that feed on this group of trees and parasitic plants. It should be noted that this chapter contains some overlaps with, as well as updates to, a previous publication in the FAO Non-Wood Forest Products Series No. 12 [FAO, 1995] since several mushrooms grow both with broad-leaved trees and conifers.
Mushrooms are the reproductive structures of fungi and are also known as sporocarps or fruiting bodies. While some mushrooms are highly toxic and can be fatal if eaten, many species are edible. Some are so flavourful that they are major food items in many human cultures throughout the world. Many species of edible mushrooms occur in forests and are harvested either commercially or as an outdoor recreation activity.
Fungi are lower plants that lack chlorophyll. They are, therefore, unable to manufacture nutrients from sunlight through photosynthesis as do green plants. In order to survive, fungi must function either as parasites, often causing disease in higher plants or animals; saprophytes, causing the breakdown of dead organic matter; or as mutualists or symbionts with green plants. In the case of mutualism or symbiosis, both the fungus and the green plant derive benefits from the association.
The predominant form of symbiosis between fungi and trees occurs with tree roots producing structures called mycorrhizae. Mycorrhiza means “fungus-root” and describes the association of specialized soil fungi with the tiny feeder roots of forest trees and shrubs. Mycorrhyzal fungi function as an extension of the plant’s root system and are the means by which almost all higher plants take up water and minerals from the soil. Only a few higher plants are known to lack mycorrhizal associations [Manion, 1991]. The uptake of phosphorus and nitrogen are particularly important functions of these fungi. Mycorrhizal fungi directly enhance tree survival and growth [Molina et al., 1993].
Many species of forest fungi produce delicately flavoured edible mushrooms that are harvested in large quantities, and some are cultivated under semi-artificial conditions. Primarily mycorrhyzal fungi produce them, but several saprophytic and parasitic fungi also produce highly flavourful mushrooms.
Boletus edulis is a mycorrhyzal fungus that grows in association with a wide variety of trees, including both conifers and broad-leaved species. The mushrooms produced by this fungus are widely used in a number of cuisines, especially in Europe where it is one of the most sought-after edible mushrooms. It goes by many common names including cep or cepe de Bordeaux (France), king bolete or penny bun mushroom (English), porcino (Italy), Steinpilz (Germany), zhutui mo (North China) and dajiao gu (South China).
The mushroom produced by this fungus is highly variable, and some mycologists have split the fungus into a number of distinct species. A common characteristic of the mushroom is a wide, barrel-shaped stem that has a fine reticulate pattern on its surface.[50]
Boletus edulis occurs in temperate zone forests throughout the northern hemisphere and produces fruiting bodies from the soil as scattered individuals or in small groups [Molina et al., 1993]. It is found throughout North America as far south as Mexico, in Europe from the northern part of the Nordic countries south to southern Greece; Italy; and, in the Near East, as far east as Afghanistan. It is also found throughout China. In the United Kingdom, B. edulis is found associated with birch (Betula palustris), oaks (Quercus robur and Q. petraea) and beech (Fagus sylvatica). In China it grows under mixed forests of pine and oak [Dickinson and Lucas, 1979].
The strong, distinctive flavour of this mushroom has been appreciated since Roman times. Dishes containing boletes were often used by the Romans to conceal poisons used to assassinate politicians and other public figures. They were also believed to have a number of medicinal properties, including the removal of freckles and blemishes, and a salve was prepared from boletes to treat dog bites [Dickinson and Lucas, 1979].
Boletus edulis is harvested in the wild. In Poland, it is the principal wild mushroom harvested [Grochowski, 1966]. In the Casentino, a mountainous area in the region of Tuscany, Italy, income and benefits derived from harvesting B. edulis are considered to be significant. About 20 percent of the total harvest is for personal use, and the remainder is sold to restaurants, local stores and wholesalers. Mushroom collectors are mostly from the lower to middle income classes; women are the most numerous group of collectors and nearly half of the collectors are between 50 and 60 years old [Farolfi, 1990]. Chestnut (Castania sativa) orchards are a favourable habitat for growth of B. edulis in Italy, and in some cases the yield of edible king boletes harvested from these orchards is worth more than the chestnut crop.[51]
Boletes are harvested in British Columbia, mainly from Haida Gwaii (Queen Charlotte Islands) and the Prince George area. In a good fruiting year, approximately 100 000 kg of fresh boletes are harvested. While in a bad year there may be no harvest at all.[52] On average, pickers are paid $Can 2.50/lb of boletes and exporters receive around US$8/lb of boletes landed and fresh, around US$75.00/kg of dried and landed, and around US$5.00-6.00/kg of frozen.
Approximately 90 percent of all harvested boletes are exported dried or frozen and only around 10 percent of the harvest is exported fresh. Boletes are one of the first wild food mushrooms to be attacked by pests, and there is currently a world shortage of king boletes [Russel and Lipsey, 1999].[53]
This mushroom has a firm, meaty texture that stands up well to prolonged cooking. Consequently it is a popular ingredient in a variety of stews, casseroles and sauces. B. edulis can also be easily dried, a form that permits storage for extended periods (Figure 9.1). In some parts of Europe they are dried on strings and stored for winter use. It is also a common ingredient in dried soup mixes [Dickinson and Lucas, 1979].
The fungus that produces the northwest matsutake mushroom (Tricholoma magnivelare), forms ectomycorrhizal associations with many tree species throughout its natural range in western North America, especially various species of Pinus [Molina et al., 1993; Ciesla, 1998]. In the Pacific Northwest region of the United States, it is the most valuable of the commercially harvested edible mushrooms [Schlosser and Blatner, 1995]. This mushroom is sold in large quantities to Japan where it is an acceptable substitute for the Japanese matsutake (Tricholoma matsutake), a species that grows in Pinus densiflora forests and commands exorbitant prices.
The matsutake mushroom is robust and white in colour when first formed. Later it develops pale brown to yellow stains. The stout stem is solid, tough and fibrous. It is smooth above and scaly below the thick, sheathing ring that flares out in young specimens. The mushrooms have a distinct spicy-aromatic odour, reminiscent of sweet cinnamon [Mollina et al., 1993].
T. magnivelare is also associated with forests of tanoak (Lithocarpus densiflorus) in northern California and western Oregon. Among the Karuk, Yurok and Hupa people, three indigenous tribes which occupy portions of northern California, T. magnivalare is known as the tanoak mushroom and is considered to be an important traditional food. In the Karuk language, T. magnivelare is known as haiwish. The earliest documentation of the Karuk use of tanoak mushrooms dates from ethnobotanical field studies conducted in 1939, which reported: “A certain mushroom, found in November, is cooked on coals and eaten.” [Richards, 1997; Schenck and Gifford, 1952].
The high demand for T. magnivelare mushrooms in Japan led to a massive increase in commercial harvesting of this species on public lands in the western United States beginning in the late 1980s. Until about 1991, there was little commercial mushroom harvesting on Karuk ancestral lands. As commercial pickers arrived in greater numbers, local tribal members complained that their traditional gathering sites, many of which were on lands administered by USDA Forest Service, were being overharvested. In early 1993, the Karuk tribe appealed a decision made by the Klamath National Forest in northern California to allow a commercial mushroom harvest season. As a result, no commercial permits were issued, and studies on resource values assigned to this mushroom and the basis for the resource conflict were established. Resultant work, some of which is still in progress, indicate that the Karuk had developed mushroom hunting techniques based on knowledge of favourable sites, weather and phenology of associated plants. They also engaged in harvesting practices that they believed would sustain the population of the fungus. These practices included twisting off the mushrooms so as not to disturb the fungus mycellium, leaving small mushrooms to grow and fruit and replacing leaf litter in sites where mushrooms have been harvested in order to maintain soil moisture and a more favourable habitat for production of fruiting bodies. The effect of these traditional harvesting practices on sustainability of mushroom harvests requires testing in replicated field trials [Richards, 1997].
Truffles (Tuber spp.) are rounded, potato-shaped mushrooms with a subterranean habit. They are the fruiting bodies of mychorrhizal fungi associated with the roots of various species of beech, oak and other broad-leaved trees [Dickinson and Lucas, 1979]. One species, T. gibossum, is associated exclusively with Douglas fir (Pseudotsuga menziesii) in the Pacific coast of North America [Molina et al., 1993].
Several European species are considered to be prized delicacies. The black Périgord truffle (Tuber melanosporum) is widely used in Italian and French cuisines. This truffle is found in oak forests throughout much of Europe but the centre of production of the mushrooms is southwestern France where they occur in light, porous, clay marl. In Italy it is known as tartufo nero, and in the region of Umbria it is an ingredient in pasta dishes and in an amaro, an after-dinner liqueur [author’s observation]. The white Piedmont truffle (T. magnatum) is the most sought-after species in Italy, where it is added in thin slices to a variety of pasta dishes to which they impart a distinctive, musky flavour. This truffle is produced in the region from the Astigiano to the Canallese rivers in Alba (Piedmont Region), where most collection occurs from October through December [Moora, 1955]. The summer truffle (T. aestivum) occurs in the beech forests in the chalk downs of the United Kingdom, where a cottage industry based on truffle hunting existed during the eighteenth century. Truffles were collected and marketed until the 1930s but are now considered to be too small to merit collection [Dickinson and Lucas, 1979].
The unusual habitat and appearance of truffles caused considerable debate as to their origin. The Roman naturalist and writer Pliny described truffles as “calluses of the soil”. The Greek biographer Plutarch explained that their existence was the combined action of thunder, rain and the warmth of the soil. During the sixteenth century, it was widely believed that truffles were the result of the semen of rutting deer. During the nineteenth century, they were believed to be a gall produced by oak roots. Later in that century a theory was postulated that the truffle fly, an insect commonly associated with the fruiting bodies, stung the roots of oak trees causing the gall-like truffles to grow [Dickinson and Lucas, 1979].
While much truffle gathering occurs in natural forests, the black Périgord truffle has been grown in a more or less organized fashion since about 1810, using an indirect cultivation procedure. A French farmer by the name of Joseph Talon established an oak plantation by planting acorns. After a few years, truffles began to appear in the plantation. When he repeated the exercise several years later with the specific intent to produce truffles and succeeded, he had begun an indirect method of truffle cultivation. Today a sizeable portion of truffles harvested from France and exported are obtained through establishment of new oak plantings [Dickinson and Lyons, 1979]. At present truffles are the only ectomycorrhizal food fungus which is in widespread cultivation in the Pacific Northwest (only in Washington and Oregon states) [Russel and Lipsey, 1999].
The subterranean habitat of truffles presents some unique challenges for harvesting. Pigs and dogs are often used to sniff out truffles. While pigs are reputed to have the keenest nose for truffles, they are not easily led and tend to go astray. Moreover, they tend to eat the truffles they detect. A well-trained dog is preferable because it can detect truffles from 30 to 50 m and will not eat the mushrooms. Once detected, the truffle is lifted out of the ground with a spiked stick.
The secrets of where, when and how to collect truffles are jealously guarded, and knowledge of the best places to find truffles is passed down from father to son, generation after generation. While Italian law specifies that truffles are public property, about 80 percent of the white truffle harvest is handled by one family [Dickinson and Lucas, 1979].
In 1992, approximately 32 000 kg of Oregon white truffle (Tuber gibbosum) were harvested in Oregon and Washington. At an average the price reached US$ 32/lb [Russel and Lipsey, 1999].
In France, truffle production toward the end of the nineteenth century was estimated at 200-250 t/a. This gradually grew to 1 200 t/a by the mid-1960s without any concern for overproduction [Cagnairt, 1968]. French truffle production has declined in recent years, however, and by 1988 was down to about 20 t [Iqbal, 1993].
France, Spain and Italy are the major exporters of black truffles. In Spain truffle hunting was a local enterprise until about 1954 when black truffles were exported to France to meet a growing demand [Nicolas, 1973]. Currently, approximately 15 t/a to 30 t/a are collected in Spain. In 1993 its economic value reached Ptas 411 million (25 361 t) [Cesaro et al.). Other principal importers of black truffles are Germany, Switzerland and the United States. White truffles, which are less known, are exported primarily to restaurants in the United States [Ciani, 1990], but markets for this higher priced truffle have developed in Belgium, France, South Africa and Switzerland [Morra, 1955]. In 1989, the United States imported 5.4 t of fresh or chilled truffles, mainly from Italy and France at a value of US$ 1.48 million or US$ 273/kg [Iqbal, 1993].
The high prices that truffle commands has led to instances of fraud necessitating regulation of this industry. French law restricts the word truffe to members of the genus Tuber. Marketed black truffles must consist of only T. melanosporum and T. brumales (winter truffles). T. uncinatum may comprise up to two percent of fresh, labelled black truffles because identification among closely related species is not possible without magnification. The use of summer white truffles (T. aestivum) in pâtés is also regulated. Artificial colouring of white truffles to make them appear black is illegal [Cagniart, 1968].
In the Alba area of the Piedmont Region of Italy, where white truffles are harvested, some 12 t of truffles are officially collected at an average value of US$ 2000/kg. A similar quantity is collected illegally and sold unofficially. The collection of truffles along with other agricultural products, especially wine, gives Alba one of the highest percentages of agricultural workers and, at the same time, one of the highest average income rates. In addition to the truffle collecting, related activities such as food-processing industries, restaurants and on-farm tourism (agriturismo) are all growing rapidly.
The Umbria Region of Italy, an area with extensive oak forests and woodlands, is a major area for black truffle production. Rules and regulations that govern the harvesting, cultivation and conservation and marketing of truffles have been developed. Truffle collectors have open access to the forests and other lands not under cultivation but must be licensed before they can legally gather truffles. Truffles under managed production are the property of the landowner and are subject to separate regulation. Seasons for collecting each of nine species of indigenous truffles are stipulated. Immature truffles are protected, and no truffle hunting is to take place at night. Excavations are to be covered immediately after truffles are harvested. Before a licence is issued, truffle hunters must pass an examination about collection methods; conservation; local and national laws; and the biology and identification of local species. The government of Umbria is required to fund training for technical personnel to oversee truffle harvests; conduct research and public education; and to conduct marketing initiatives. Fines are established for hunting truffles without a trained dog, illegal digging, harvesting of small truffles and improper terracing of hillsides [Giunta Regionale del’Umbria, 1987].
Shiitake (pronounced sheeta’kay) is the fruiting body of the fungus Lentinula edodes. This is a saprophytic fungus that colonizes the dead wood of various species of trees. In Japan, it is found primarily on Quercus cuspidata, commonly known as shii [Wolf and Wolf, 1947]. Shiitake is the second most widely cultivated mushroom in the world, second only to Agaricus mellia.
The shiitake mushroom has a round cap with a diameter that can reach up to 15 cm. Coloration varies from dark brown with patterns formed by white spots around the edges of the cap.
The oldest record regarding the shiitake mushroom dates back to the year AD199 at the time of Emperor Chuai in Japan. The cultivation of shiitake mushrooms has its origins in China, however, during the Sung Dynasty (AD 960-1127). The cultivation technique was extended to Japan where it was later perfected. In both China and Japan, shiitake is considered to be an “elixir of life” and is widely consumed.[54]
The shiitake mushroom grows naturally on logs of beech (Fagus spp.), chestnut (Castanea spp.), oak (Quercus spp.) and hornbeam (Carpinus spp.). Shiitake cultivation is carried out on specially cut branches from suitable trees.
In its most primitive form, logs are placed in contact with naturally infected wood, and the fungus spreads to the fresh substrate. All that is required is a favourable site to stack logs so that fruiting is encouraged. A more systematic regime involves soaking logs in water and pounding them to break the bark. Another procedure involves making holes in the bark with a broad drill or specially designed hammer. The logs are then inoculated with a spore suspension that is prepared from mature fruiting bodies or a spawn made from mycelium grown on wood chips or sawdust. The infected logs are placed in a carefully selected site in a forest known as a “laying yard.” The choice of site is important. If it is too moist, natural wood decaying competitors would be favoured and the shiitake crop would be reduced or lost. The best laying yards are in ventilated clearings at the edges of a forest. The logs are placed crosswise and at slight angle to the ground.
The cultivation of shiitake is a comparatively long process. Logs remain in the laying yard for five to eight months and are watered when dry. They are then removed to a raising yard, usually in winter, where environmental conditions favour fruiting. The raising yard is more heavily shaded and watered regularly, and the logs are stacked in an upright position against fences. The first mushroom crops appear the following spring. Once logs have begun to produce mushrooms, they will continue to do so for several years in spring and autumn. The maximum cropping period on a given set of logs is about six years [Dickinson and Lucas, 1979].
One of the advantages of shiitake production is that it makes use of logs and limbs that are too small to be suitable for other purposes. Logs must be live, cut during the dormant season and free from disease [Thomas and Schumann, 1993].
For maximum flavour and texture, the mushrooms are harvested when young. Most of the shiitake crop is dried either in the sun or in specially constructed drying houses. Shiitakes are normally exported in dry form although some are canned or pickled [Dickinson and Lucas, 1979].
Shiitake cultivation is widely practised in Asia, with China, Korea, Japan, Singapore, and Thailand being producers of this mushroom. Several western countries including Brazil, Canada, the Netherlands, the United Kingdom [Slee 1991] and the United States have begun commercial production.[55]
Japan currently produces about 90 percent of the world’s shiitake mushrooms [Thomas and Schumann, 1993]. Shiitake cultivation in Japan is currently a major non-wood forest enterprise and increased production has been a significant factor in the increased contribution of non-wood forest products to total forest earnings. In 1960, only 3-4 percent of total forest earnings were from non-wood products. By 1980, the contribution had increased to 13 percent. Changes in eating habits of the Japanese people after the Second World War have had a significant influence on the demand for shiitake. These changes included a shift toward non-staple foods including mushrooms, an increased trend toward eating out and a shift toward processed and already cooked foods. Prior to the 1950s, shiitake mushrooms were produced largely for export to China and Southeast Asia, and domestic demand was low. In addition, the supply was kept low because of inefficiencies in cultivation. Edible mushroom production is considered to be an important source of income for rural household economies, especially during periods when the demand for wood products is in decline. Moreover, shiitake cultivation has filled a void left by declining demands for charcoal, once a key source of income for mountain villagers [Noda, 1988].
The shiitake mushroom is the most widely cultivated speciality mushroom in the world and is both a prized medicine and a culinary delight. In Japan, shiitake is one of the most popular sources of protein whereas it is a major staple in China and other parts of the Pacific Rim. By being appetizing, nourishing, dietetic and healthful, shiitake is a highly valuable food source. Shiitake has adequate nutritional qualities to serve as a main dish, and it adapts well to recipes as a meat substitute.
Shiitake has also medicinal properties and has traditionally been used in folk medicine by having antifungal, anti-tumour and antiviral effects. It is believed to fortify the immune system's combating of viruses and bacteria through its polysaccharides which increase the level of macrophage activity [Russel and Lipsey, 1999]. Current research reveals that the mushroom combats hepatitis B and certain types of cancer. Shiitake might also be an effective treatment for the HIV-virus; however this is still unproved.[56]
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Box 9.1 Shiitake production: A family enterprise The Krogmeier family of Spring Point, Iowa, are an example of successful shiitake producers. They began with a 200 log operation in 1987 with relatively little capital investment. They purchased their spawn through a shiitake mushroom producers association that was formed in Iowa because of a growing interest in shiitake production. The Krogmeier’s initial supply of oak wood was free because a family member owned a small woodlot. They used a garage to store logs and force the shiitake fruiting. First year results were so successful that they quickly increased their production to a 3 000 log operation. This size of operation requires cutting of 600-700 new logs per year. Yield is 0.11- 0.22 kg mushrooms per log. Approximately 15 to 20 hours of labour are required per week and a net profit of $US10 000-12 000 is realized. The mushrooms are sold through the same association from which they obtained the spawn. The association can sell virtually any amount of mushrooms grown. Most are sold to food processing companies at ca $US13.00/kg of which the association receives 80 percent (Thomas and Schumann, 1993) |
Korea has a small shiitake industry but, production is currently hampered by the small scale of cultivation, lack of efficient technology, low labour productivity and lack of consistent management [Park, 1984]. A shiitake-producing industry has developed in the United States over the past 20 years. Cultivation is typically a family-run operation and provides a supplemental income for rural families [Thomas and Schumann, 1993]. In Brazil, the commercial cultivation of shiitake began during the early 1990s, mostly by small producers where the wood of Eucalyptus spp. has been found to be a good growth medium.[57]
Morels (Morchella spp.) are saprophytic fungi that are found in both conifer and broad-leaved temperate forests. All of the species in this genus are edible and delicious and, with the possible exception of truffles, are considered the most delectable of mushrooms [Alexopoulos, 1962]. They are highly prized for their culinary uses, particularly as a gourmet food and are used in gravies, sauces and soups. Morels are not only delicious, they are also a healthy and nutritious food. They contain 42 percent protein on a dry weight basis, are low in calories and rich in minerals [Iqbal, 1993]. Some individuals may have adverse reactions from eating morels, however, especially when they are consumed with alcohol. Morels should never be eaten raw [Molina et al., 1993].
The mushroom produced by the morel fungi has a characteristic appearance although the mushrooms of several closely related fungi have somewhat similar appearances. They have been likened to a pine cone perched on a stem. The fertile cap (pine-cone portion) is honeycombed with pits and ridges. The cap and stem are hollow and the cap rises continuously from the stem. The stem colour ranges from white to pale brown, and the colour of the cap ranges from pale yellow-brown through tan, brown and grey-brown. The pits are typically the same colour as the ridges or slightly darker [Molina et al., 1993].
Morels grow in the temperate forests of Asia, Europe, the Near East and North America and are associated with many temperate trees [Iqbal, 1993]. They tend to be abundant after a wildfire has passed through an area and appear in early spring, shortly after snow melt. In Europe, fires have been deliberately started in forests in hopes that they would encourage development of morels [Arora, 1986; Molina et al., 1993; Phillips, 1991]. Some species, such as M. angusticeps, are common in forests of pine, Douglas fir or various species of Populus. M. esculenta, a white morel, is found associated with forests of Carya and Liriodendron tulipifera in the eastern United States [Phillips, 1991].
In a good year, 225 000 kg of morels are harvested in British Columbia and in the Yukon, whereas it might fall to 10 000-20 000 kg in a bad year. In the Pacific Northwest the harvest reaches 602 649 kg [National Aboriginal Forestry Association, 1999].
Pickers receive on average $Can 3.00/lb of fresh morels. For fresh and landed morels the exporters receive US$ 18.00-22.00/lb and for dried and landed in the Unites States and Europe US$ 150 to $200/kg. Morels are exported fresh only about two weeks of the entire growing season because they are rapidly attacked by pests [Russel and Lipsey, 1999].
Total world production of morels is estimated to be about 150 t dry weight, equivalent to 1.5 million t of fresh morels. India and Pakistan are the major producing countries, each producing about 50 t/a of dry morels, all of which are exported. Afghanistan and China are two additional countries that trade morels internationally. All are gathered in forests although some research is under way to develop means of artificial cultivation. In Pakistan, there is a race between men, women and children to see who can handpick the greatest quantity of morels. These are sold fresh or in dried form to local hopkeepers, who dry them. No further processing is involved until they reach the wholesalers/exporters. The price for dried morels in Pakistan in 1991 was US$ 133 per kg, with gatherers receiving one-half to two-thirds of this price. The exporters de-stalk, grade and sometimes fumigate the morels before they are exported. France, Germany and Switzerland are the main importers of dried morels from India and Pakistan. According to unpublished records of the ITC, the import of dried morels to Switzerland and member countries of the European Union ranges between 100 t/a and 120 t/a [Iqbal, 1993; National Aboriginal Forestry Association, 1999].
International trade in fresh morels is limited because of the short life of these mushrooms. However, short distances between some producing countries and markets make trade in fresh morels possible, for example between Turkey and western Europe [Iqbal, 1983].
The fungi of the genus Cytarria are parasites of various species of Nothofagus in South America. They infect the twigs, branches and occasionally the main stems of host trees and sometimes cause growth loss and deformity. Some species produce edible mushrooms known as digüeñe, caracucha or pinatra.[58] In southern Chile, fruiting bodies of C. darwinii are sold along roadsides and markets and are a popular ingredient in salads [author’s observation] and are also good tasting when fried in butter. C. darwinii has been a traditional food of the indigenous people of Tierra del Fuego at the southern tip of South America [Wolf and Wolf, 1947]. The mushroom is round, white, yellowish brown or orange in colour with a dimpled texture and resembles a golf ball (Figure 9.2). They appear in clusters on infected portions of host trees in spring, coinciding with leaf flush on various species of Nothofagus including N. antarctica, N. dombeyii, N. obliqua [Baldini, 1994; Minter et al., 1987].
According to Gamundi and Horak (1995), four species of Cytarra are found in the forests of Argentine Patagonia, C. darwinii, C. johowii, C.hookeri, and C. harioti. While C. darwinii is good tasting, C. johowii, and C.hookeri have a mouldy flavour. The fruiting bodies of C. harioti were used by indigenous people of the region for production of an alcoholic drink.
Figure 9.2a Fruiting bodies of: Boletus edulis, Tricholoma magnivelare.
Figure 9.2b Fruiting bodies of: Tuber melanosporum.
Figure 9.2c Fruiting bodies of: Morchella conica
Figure 9.2d Fruiting bodies of: Lentinula edodes and Cytarria darwinii, (on Nothofagus spp).
Trametes versicolor is a wood-rotting polypore that grows on the side of felled oak logs and other dead or dying hardwoods.
Trametes versicolor has medicinal properties and is used in cancer treatments, both as preventative and as curative. The mushroom accounts for around 16 percent of Japan's national expenditures on anti-cancer agents. The species ingredients are also thought to enhance T-cell proliferation and are taken in the Asian countries as a nutraceutical. Furthermore, Trametes versicolor is used as immune stimulant; antibiotic; against pulmonary disorders; as antiviral; against hepatitis; and for the infections of the respiratory, urinary and digestive tracts.
In Japan a nutritional supplement containing T. versicolor is generally used as a health food, and testing in Japan has shown that it has cholesterol-lowering properties. Other names used for Trametes versicolor are Yun-Zhi, Kawaratake and Coliolus versicolor [Russel and Lipsey, 1999; Tedder, Mitchell and Farran, 2000].[59]
Other fungi of medicinal interest are species such as Formitopsis pinicola, Laetiporus sulphureus (common name: chicken of the woods), Ganoderma Tsugare and Ganoderma appalanatum. The latter grows both with broad-leaved and coniferous trees and is mostly found in the temperate zones of the Northern Hemisphere[60] [Tedder, Mitchell and Farran 2000].
Silk is a fibre produced by certain caterpillars when they spin cocoons in which to pupate. It is the most luxurious of fibres, with an unsurpassed natural beauty, lustre and softness. It takes dyes well and, while seemingly delicate, it is one of the strongest, toughest and durable fibres known.
There are two types of silk known, “domestic” silk and “wild” silk. Domestic silk is the product of the domestic silkworm (Bombyx mori), which feeds on the foliage of mulberry (Morus spp.). This insect has been cultivated for centuries for its ability to produce a fine-quality white silk, which is called mulberry silk. Bombyx mori has become so domesticated that it has lost its natural pigmentation and its ability to grasp foliage so that it must be raised under artificial conditions. It can no longer survive in the wild. “Wild” silk, on the other hand, is produced by a number of species of caterpillars, many of which feed on the foliage of temperate broad-leaved trees. The silk they produce is usually not white but ranges in colour from light yellow, light to medium beige to dark grey. The colour comes from the diet of the wild caterpillar. If it happens to feed on foliage that is high in tannin content, the tannin becomes part of the silk and colours it [Kolander, 1985].
Silk production has its origins in China. A writing from AD 90 by Ss-ma Ch’ién tells a story of Siling, the wife of a fabled “Yellow Emperor,” Huang-ti. One day, according to the story, she dropped a cocoon into her cup of hot tea. It began to unravel and gave her the idea of unreeling the cocoons into long floating threads of fibre. Silk was undoubtedly in use in China long before this story was written, however. A symbol for silk was part of the Chinese written language at the time of Huang-ti and Si-ling, about 2600 BC.
Although silk cultivation began in China and fragments of silk as old as 1 500 BC have been found in this country, the oldest written record of the use of silk comes from India. The Ramayana and the Mahabharata speak of silk weaving. These Sanskrit epics are the sacred texts of the Aryans who in 2000 BC or so came down from the northern plains and eventually established an empire from India west to the Mediterranean. The first mention of silk in western literature is by Aristotle about 300 BC, where he mentions that the source of silk is a “curious horned worm.” By the time of the Han Dynasty (around 200 BC to AD 200), silk had become so abundant in China that it was part of a soldier’s wages.
The establishment of the Silk Road across China, the Near East and finally the Mediterranean region (Che Muqi, 1989] marks the beginning of abundant silk in the West. However, the culture of silkworms was kept a carefully guarded secret by Asian cultures. In Rome, wealthy women unravelled the Chinese silks with their heavy designs and rewove them into revealing gauzes or into tapestries. The Persian merchants soon established themselves as the sole middlemen between East and West in silk trade. The actual culture of silk by western civilizations resulted when war broke out between Byzantium and Persia around AD 500 and the west was cut off from its supply. It is said that two Nestorian monks, who had once lived in China, offered to return and smuggle out the starts of sericulture: silkworm eggs and white mulberry seeds. Two years later, they returned to Constantinople (Istanbul) where they were housed in palace grounds and slowly began the culture of silkworms. All races of European silkworms through the 1700s descended from these first eggs.
The Arabs were influential in the spread of silk throughout the Mediterranean Region. From its establishment in Turkey and Greece, they introduced it into the Italian Island of Sicily. Silk culture went hand in hand with silk weaving wherever this fibre was introduced. Eventually silk found its way into the British Isles, but sericulture was unsuccessful because of the cold, damp climate of this area.
Silk culture was introduced into Japan around AD 200 when a Chinese emperor exchanged gifts with Japanese envoys. The most treasured of the gifts were silkworm eggs. At this time sericulture was a closely guarded secret. Soon after, an exiled Chinese prince, his household and his followers fled to Japan. There they took up silk weaving as their livelihood and thus transplanted the traditional skills of China into Japan were a silk industry developed that took on its own character.
Synthetic fibres such as nylon and rayon replaced silk as a fibre in the United States market during the second world war when the sources of silk were cut off. The Government of the United States subsidized the nylon industry because it needed a silk substitute for balloons and parachutes. Despite the availability of low-cost synthetic substitutes, there is still a high demand for silk products [Kolander, 1985].
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Box 9.2 Silk culture comes to India The domesticated silkworm of China is said to have been introduced into India sometime prior to AD 200. It is said that a Chinese princess, married off to a distant foreign king, smuggled silkworm eggs out of China in her head-dress, possibly because she wanted to continue her sericulture and weaving, the preferred pastimes of Chinese women. Perhaps she also shrewdly planned to bring a dowry to her husband that was so valuable, she would never be slighted. While India has many species of wild silkworms, the delicacy and shimmering whiteness of the domestic silkworm, Bombyx mori, has always been admired (Kolander, 1985) |
Silk has always been an expensive commodity because the raising of silkworms is a labour-intensive process, one that has not changed significantly over time (Figure 9.3). Approximately one month is required for the silkworm larvae to complete their feeding cycle and transform into silk-covered pupal cocoons. During this time, the larvae must be fed ever-increasing amounts of handpicked mulberry leaves. If the leaves are dirty, they must be washed before being feed to the caterpillars.
Damp weather or a sudden onset of cold weather can cause disease among the larvae [Kolander, 1985]. Mature larvae must be fed two to three time per day [author’s observation] and diseased individuals must be removed by hand in order to prevent the spread of disease to healthy larvae (Figures 9.4 and 9.5).
Approximately two full-grown mulberry trees and 4 000 silkworm eggs are required to produce 5.5 kg of silk. The proportion of raw, reeled silk to cocoons varies because the reliability of the cocoons depends on the strength of the fibre and its uniformity, the proportion of silk to pupa and whether or not the cocoons are weighed fresh or dry. The usual ratio is 12:1, i.e. 12 kg of cocoons equal about one kg of reeled silk and an equal amount of unreliable spinning silk. In Japan, where great care is given to silk production, the ratio is about 6:1; and in Italy, at the height of its silk industry at the turn of the century, supposedly cocoons with a reliability ratio of 3:1 to 4:1 were produced.
Modern breeding and management techniques of both mulberry and silk worms in Japan have doubled the production of silk per hectare of mulberries during the past 20 years. The average annual crop averages 675 kg/ha, yielding slightly more than 100 kg of raw reeled silk plus some spinning fibre. These numbers are based on two rearing periods per year, one in early spring and a second in late fall. The mulberries are trimmed as bushes to allow easy picking of foliage [Kohlander, 1985].
World production of silk is nearly as great as at any previous time in human history and is increasing. Japan produces about 20 000 t/a of raw-reeled silk and imports an additional quantity. India produces large amounts of both cultivated and wild silk, most of which are used domestically. In many parts of India, sericulture and silk weaving are still done on a small village scale. China has historically produced more silk than any other area of the world, but today only a small portion is used domestically. Most of China’s silk crop is exported to Europe [Kohlander, 1985].
Wild silk, also known as tussah silk, is an abundant form of silk. There are many kinds of wild silks, each with its own characteristics. For example, some wild silks are dark coloured but dye well. Others are nearly white in colour but do not take dyes. Some are fine, others are strong; some are reliable, whereas others are not; and some have distinctive odours. Silk-producing caterpillars can be found anywhere although some of the best known occur in tropical, subtropical and warm temperate regions of Asia. Several species of caterpillars, capable of producing wild silk, feed on the foliage of temperate broad-leaved hardwoods (Tables 9.1 and 9.2).
Table 9.1 Asian wild silkworms that feed on temperate broad-leaved trees and shrubs
|
Species |
Range |
Hosts |
Remarks |
|
|
Chinese monthly |
China |
Morus spp. |
Small cocoon, prolific. |
|
| |
Bombyx sinensis |
|
|
|
|
Chinese tussah |
China |
Quercus spp. |
Colour and quality of silk depend on climate and soil. |
|
| |
Antheraea pernyi |
|
|
|
|
Yama-mai silk |
Japan |
Quercus spp. |
White silk but does not dye well. Very strong and elastic |
|
| |
Antheraea yama-mai |
|
|
|
|
Muga silk |
Assam |
Various hosts |
Dark in colour takes dyes well. Once reserved for the exclusive use of the Rajas. |
|
| |
Antheraea assamensis |
|
|
|
|
Cynthia moth |
China |
Alianthus glandulosa |
Somewhat domesticated, introduced into North America |
|
| |
Attacus cynthia |
|
Prunus spp., Platanus spp. Syringa vulgaris |
|
Source: Kolander, 1985
Table 9.2 North American wild silkworms that feed on temperate broad-leaved trees and shrubs
|
Species |
Hosts |
Remarks |
|
|
Polyphemus moth |
Betula spp. |
Potentially the most valuable of NA silkworms. |
|
| |
Telea polyphemus |
Quercus spp. |
|
|
Cercropia moth |
Various hosts |
Quality of the silk depends on host plant fed upon by the larvae. |
|
| |
Hyalphora cercropia |
|
|
|
Promethea or spice bush moth |
Various hosts |
|
|
| |
Calasoma promethia |
|
|
|
Luna moth |
Carya spp. Juglans spp. |
|
|
|
Liquidambar styraciflua |
|
||
|
Io moth |
Various hosts |
|
|
| |
Automeris io |
|
|
(Source: Drooz, 1985; Kolander, 1985)
Wild silk is a coarser fibre than cultivated silk. This makes it more durable and more practical for clothing. Traditional uses include pile fabrics and carpets. Because it grows without cultivation and needs only to be gathered and processed, wild silk is usually less expensive than cultivated white silk. It is also rarely reeled in order to ensure a continuing supply.
The cocoons are gathered after the moth has emerged. Spinning, rather than reeling, makes for less cost and means that yarns can be made in sizes like wool or cotton, heavy enough to be attractive to hand craftsmen.
In China, tussah silk produced by the Chinese tussah or tussur moth (Antheraea pernyi) is semi-cultivated. This silk is also called tassar. The larvae feed on various species of oaks (Quercus spp.). The oaks on which the caterpillars feed are pruned into shrubs 1.5-2 m high on which the larvae are raised. Two annual crops are obtained. The small spring crop is used exclusively as breeding stock for the large autumn crop. The silk of the autumn crop is mostly reeled. Yields average approximately 45 kg/ha of reeled fibre and about 68 kg/ha of spinning fibre [Kolander, 1985]. The city of Dandong, in Liaoning Province has been a center for tussah silk production for two centuries and in 1980 provided about 70 percent of China’s output. Tussah silk production fluctuates; in 1980, 75 000 tons were produced and about 50 000 tons were produced each year between 1987 - 1989 (Peigler 1999).
The tensan silk moth, Antherraea yamamai, has been cultivated in Japan for more than 1000 years. It was introduced into Austria in the 1860’s by Baron de Bretton. Although not used commercially in Europe today, the moth has established itself in oak forests of lower Austria and northern Italy and is considered a pest. Today tensan silk is produced in only a few places in Japan. It has great cultural and ritualistic significance. Items produced from this silk include small tablecloths, neckties, belts, cloths for Buddhist altars and family frames. Many of these items cost the equivalent of thousands of $US (Peigler 1999).
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Box 9.3 Silkworms and the gypsy moth The gypsy moth (Lymantria dispar) is an insect native to Europe and Asia that feeds on a wide range of host plants including birches, poplars, oaks and other temperate broad-leaved trees. In 1869, a French scientist by the name of L. Troulvelot brought egg masses of this insect from France into Massachusetts for the purpose of cross breeding them with the domestic silkworm and develop an alternative source of silk. His experiments failed, but during the course of his research, some gypsy moth larvae escaped and became established in the surrounding oak forests. Within 20 years, the insect spread over an area of 900 km2 around Boston, causing severe damage to forest, shade and fruit trees. The insect has become one of the most serious forest and urban pests in the northeastern United States and Canada and in some years, millions of hectares have suffered serious damage (Drooz, 1985; Leonard, 1981). |
Several scale insects (Homoptera: Coccidae) infest oaks in the Mediterranean region and are the source of a brilliant red-crimson dye. The most important is Kermococcus vermilis (= Kermes ilicis), whose primary hosts are the foliage of Quercus coccifera and Q. ilex [Schetky, 1984; Wickens 1986]. Both are evergreen oaks that are widely distributed in Mediterranean Europe and the Near East (Figure 9.6). The pigment is kermesic acid and the colour descriptors, crimson in English, carmoisine in French, karmir in Armenian, kirmiz in Persian and kirmima in Sanskrit [Gerber, 1978; Green, 1995]. The dye source is the female adult stage of this insect [Green, 1995]. At one time these insects were raised commercially in southern France, Spain and other areas of Mediterranean Europe [Adrosko, 1971]. The insects were harvested before dawn by women carrying lanterns and picking the insects from the leaves with fingernails that were kept long for this purpose [Wickens, 1986].
Kermes, also referred to as “dyers coccid,” is a dye of ancient origins, and there are records of its widespread use in the Mediterranean and Near East for dyeing wool and silk before other red dye sources were available [Green, 1998]. It may even be the oldest dyestuff known, and its use can be dated back as early as 1400 BC by the Phoenicians. Kermes colours produced by the Phoenicians were prescribed for the appointments of the tabernacle and for the “holy garments” of Aaron [Gerber, 1978]. According to Schetky (1984), alum and urine were used in the preparation of dye baths. In the Near East, a traditional scarlet fez was dyed with kermes, as was a cap of the same colour in Greece. During the Renaissance, the city of Venice, Italy, was the principal centre for kermes trade; and the dye, known as écarlate de Venise (Venetian scarlet), was quite famous. Many reds in Gothic tapestries were produced with kermes. Dyeing with kermes became known as grain or ingrain dyeing, and in William Shakespear’s Twelfth Night he uses the phrase: Tis ingrain, Sir! ‘Twill endure wind and weather [Wickens, 1986]. The dye was widely used until the middle of the sixteenth century when cochineal, a crimson dye extracted from the female adult stage of yet another scale insect, Dactylopius coccus, was discovered [Green, 1995]. This insect, which feeds on various species of prickly pear cactus (Opuntia spp.) in Mexico and Guatemala, produced higher yields of dye than could be obtained from kermes.[61] One estimate indicates that 12 times as much kermes was required to equal one part of cochineal [Bancroft, 1814]. The use of cochineal as a dye source declined with the advent of aniline dyes during the early twentieth century [Adrosko, 1971].
Today, use of kermes is restricted to a few hobbyists who prefer to work with natural dyes, and the material is difficult to obtain. According to Green (1995), while there is occasional interest in reviving kermes as a food colorant, there is little realistic prospect of it ever regaining commercial significance because of the high cost of collecting female scales.
Galls are abnormal growths on the foliage, stems and branches of trees. They can be caused by a variety of agents including virus, bacteria and insects. Several kinds of insects produce galls on trees and shrubs including aphids, flies (midges) and wasps. Gall insects have a hormonal effect on plants and can alter growth patterns. Each gall insect produces a gall of a unique morphology from which the insect species can often be identified [Berenbaum, 1994; Felt, 1940]. Heavy infestations of gall insects can cause a valued ornamental tree to be unsightly and, in extreme cases, can cause tree deformity. On the other extreme, a number of galls are the source of materials beneficial to humans and have been used to produce inks and dyes, tannin, medicinal products and food for human consumption.
Galls caused by wasps are common on oaks, and many are high in tannic and gallic acids (Figure 9.7). The high content of tannin and other materials give a number of beneficial properties to oak galls. These have been known for centuries, and some oak galls have been harvested in large quantities to be used as ingredients in medicine, inks, dyes and as a tannin source.
The most important of the insect galls is the Aleppo gall. Also known as Turkey gall, Levant gall, gall-nut, gall of commerce and ink marble, they have a spherical shape, are hard and brittle, about the size of a wild hickory nut, and appear on the stems and branches of Quercus aegilops, Q. infectoria, Q. pendiculata and other oaks. The gall is produced by a wasp of the family Cynipidae (Cynips tinctoria), which is found in eastern Europe and the Near East, including portions of Greece, Hungary, Iraq and Turkey. This gall has been of commercial importance since the time of Ancient Greece and has been used for a variety of purposes [Fagan, 1918; Felt, 1940].
The primary use of Aleppo gall was in the manufacture of an ink known as iron gallo-tannate ink or iron-gall ink. There are many published recipes (see Box 9.4), but the defining components of these inks are iron, in the form of an iron salt such as ferrous sulphate, tannic and gallic acids. The addition of an iron salt to tannic acid produces a brown to black colour. Gum arabic, another non-wood forest product, is added to the ink to delay the saturation of the paper. This ink flows well and can readily be applied to paper or parchment with a pen. The bonding of iron-gall ink with paper or parchment made it superior to carbon ink, an ink made from lampblack, for use on documents because it could not be washed from the surface as gum bound carbon ink could [Burandt, 1994]. The Aleppo gall has a particularly high tannic acid content and also contains gallic acid (Table 9.3). The acids are extracted from the Aleppo gall by soaking and boiling and were highly regarded because they produced permanent inks that did not fade. When durable ink was required, as in the case of legal documents, local laws often required that the records be made of inks produced from Aleppo gall. Ninth and tenth century monks who used it for copying manuscripts knew ink made from gall-nuts. Even as late as the early part of the twentieth century, inks purchased by the Treasury of the United States, Bank of England, the German Chancellory and the Danish Government were required to be made from acids extracted from the Aleppo gall [Fagan, 1918].
Table 9.3 Chemical content of the Aleppo gall
|
Component |
Percent |
|
|
Tannic acid |
65.0 |
|
|
Gallic acid |
2.0 |
|
|
Ellagic acid and luteo-gallic acid |
2.0 |
|
|
Chlorophyll and volatile oil |
0.7 |
|
|
Brown extractive matter |
2.5 |
|
|
Gum |
2.5 |
|
|
Starch |
2.0 |
|
|
Woody Fibre |
10.5 |
|
|
Minor components |
1.3 |
|
| |
Sugar, Albumen |
|
| |
Potassium sulphate/gallate |
|
| |
Potassium, Phosphate |
|
| |
Gallate and Oxalate of lime |
|
|
Moisture |
11.5 |
|
|
Total |
100.0 |
|
Source: Fagan 1918.
The brown to black solution produced when an iron salt is added to a tannic acid solution was also widely used as a dye. Again, the favoured tannin source was Aleppo gall. This dye was widely used for dyeing furs and leather. Another popular use was for dyeing hair black. As recently as 1914, Aleppo gall nuts valued at US$ 17 000 were imported into the United States from Baghdad, Iraq, for dyeing seal-skin furs [Berenbaum, 1994; Fagan, 1918].
The earliest use of Aleppo gall was in medicine by the Greeks and Romans. In Greece, Aleppo gall was known to be of medicinal value by Hippocrates in the fifth century BC and by Theophrastus in the third century BC. According to the Roman Pliny, Aleppo gall was used in some 23 remedies, including treatment of ulcerations of the mouth, gum disease, malformed nails, hang nails, toothache and burns. Because of their high tannic acid content, Aleppo galls were also a highly regarded tannin source for tanning hides and skins. Over 2 000 years ago, the Roman naturalist, encyclopedist and writer Pliny wrote that Aleppo galls were widely used for tanning hides [Berenbaum, 1994; Fagan, 1918].
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Box 9.4 An ancient recipe for ink According to an old Italian recipe for production of ink, ingredients include a source of tannin, an iron salt, a solvent, a thickening agent and an anti-fermentation agent. Recommended sources of tannin include gall nuts, wood and bark of oak, bark of chestnut or grape skins. Recommended iron salts are ferrous or ferric sulphate. Gum arabic, white grape skins, honey, olive oil or nut oil may be used as a thickening agent and vinegar is suggested as an anti-fermentation agent (Tiburzi, 1993). |
Many galls on oaks indigenous to Europe, North Africa and the Near East contain tannic and gallic acids and have been used for the same purposes as the Aleppo gall. Another gall that resembles the Aleppo gall and is produced by the Cynipid wasp (Cynips insana) contains 26 percent tannic acid and 1.6 percent gallic acid. The gall is known as the mad apple of Sodom, Dead Sea fruit, Mecca gall or Bussorah gall and is found on various species of Quercus in southeastern Europe and the Near East. This gall has been used in the production of a dye known as Turkey red. The knoppern or acorn gall, caused by C. quercus-calycis, occurs on several oaks in Austria, Bosnia-Herzegovina, Hungary, Serbia, Slovenia, Greece and less frequently in France, Germany, Italy and the Netherlands. This gall ranked second in importance to the Aleppo gall. In Austria it has been used by tanners and has been substituted by dyers to the Aleppo gall. The knoppern gall contains about 45-50 percent tannin. The Devonshire gall is caused by C. kollari and occurs on various oaks in central and southern Europe, North Africa and the Near East. In 1858 or so, this insect was introduced into England where concern was initially expressed about its potential to cause severe damage to oak forests. However, it was later discovered to be an excellent source of tannin for making inks [Fagan, 1918].
Some oak galls (species unspecified) are sources of hues other than the black produced by the Aleppo and related galls. When used with an alum mordant, they produce a yellow dye, when used with a chrome mordant they produce a greenish yellow colour and, when used with no mordant, can produce yellow to yellowish brown hues [Bliss, 1981]. The Navajo, an indigenous tribe of the southwestern United States, used many native plants and minerals occurring in their native area to dye wool for traditional weavings. A cone-shaped gall found on Quercus pungens, a small to medium scrub oak found in portions of western Texas, Southern New Mexico, southeastern Arizona and northern Mexico, was one of their dye sources. When used with an alum mordant, the green or brown galls produce a light gold or light yellowish-tan colour [Bryan et al., 1978; Little, 1976].
There has been little interest in the use of galls occurring on New World oaks as ingredients in inks and dyes or as a tannin source although several have been shown to have high tannin levels. Oak galls, caused by Disholcaspis weldi on Quercus reticulata, have reportedly been sold in fruit stands in Mexico; and the gall known as oak apple is said to be sweet and tasty. The gall known as black oak wheat, caused by Callirhytis spp., has been used in Arkanas and Missouri as feed for cattle, hogs, sheep, turkeys and chickens [Fagan, 1918].
The leafy mistletoes of temperate deciduous forests (Viscum album in Europe, northern Africa and the Near East and various species of Phoradendron in North America) are parasitic plants that infest many temperate broad-leaved trees. These plants have fascinated people for centuries. Their ability to stay green in winter and their seemingly magical ability to live without roots, never reaching the ground, led ancient human cultures to believe that they were divine gifts, perhaps created by thunderbolts. Mistletoes have an important place in many ancient religious rituals among tree worshippers of Western Europe, including the Celtic Druids, early Scandinavians and Germans. Ceremonies of both the summer and winter solstices involved the harvest of mistletoe plants. Druid priests cut the mistletoe with a golden sickle onto a white cloth to keep the plant from touching the ground. Mistletoe harvest was also part of Norse ceremonies involving Balder, the son of Odin. Because of its role as a parasite of the all-powerful oak (see Chapter 2), mistletoe became a symbolic source of protective and medicinal powers. The burning of oak logs, human sacrifice and the harvest of mistletoe were intertwining ceremonies. Mistletoe was also brought into houses for protection of the house and its occupants [Schumann, 1991].
In contemporary Christian cultures, the female mistletoe plant containing white, berry-like fruits, is part of the Christmas tradition. A sprig of mistletoe is often hung over a doorway and, when a man or woman walks through the doorway, it is appropriate for a member of the opposite sex to pick a berry and kiss the person. Mistletoe sprigs, collected in forests, are a popular decorative item sold during the Christmas holiday season in Europe and North America. The mistletoe sprigs are often harvested from the crown of tall trees by shooting them out with a shotgun [author’s observation]. An early use of the berries of Viscum album was to make a product known as birdlime. This is a sticky material that was spread on twigs and branches of trees by fowlers to trap birds.
Figure 9.8 Berries of Viscum album.
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[50] Source: Ian Hall, 1993 -
Invermay Agricultural Centre, New Zealand ([email protected]). [51] Source: Great Lakes Chestnut Alliance (ttp://www.traverse.com/earthkeepers/wrldprod.html) [52] The estimates for "good" and "bad" year harvest quantities are based on two sources - averages of buyer estimates at field station for their regions taken in the fall of 1997 and import data from the consuming countries. The same is valid also he harvest of morels and chanterelles in British Columbia. [53] Source : Farm business management (http://www.fbminet.ca/bc) [54] Source : Lexxa (http://www.lexxa.com.br/sunshiitake/cogumelo2.html). [55] Source: Lexxa (http://www.lexxa.com.br/sunshiitake/cogumelo2.html). [56] Source: Lycos (http://webmd.lycos.com/content/article/1677.53) Shiitake mushrooms (http://www.shiitakecenter.com/health/health.html). [57] Source: Lexxa (http://www.lexxa.com.br/sunshiitake/cogumelo2.html). [58] Information provided by Dr Hernan Peredo, Forest pathologist, Universidad Austral de Chile, Valdivia Chile. [59] Source: http://www.amoeba.com/mstravers.html [60] Source: http://cygnus.tamu.edu/PLPA/Projects/1/ganoderma_applanatum.html [61] No estimates could be found on the dye yield from the kermes scale. However, the higher yielding cochineal requires about 154 000 insects to produce one kg of dye. One ha of planted Opuntia yields about 300 kg of cochineal insects (Adrosko, 1971) |
