A number of plants and animals associated with conifers and conifer forests
are the source of valuable non-wood products, several of which are important
in local and regional economies. Others are important traditional products.
In this chapter, non-wood forest products from plants that are directly
associated with conifers and conifer forests are discussed. Examples are
edible mushrooms, edible insects, lichens and dwarf mistletoes. The latter
is a group of plants that are parasites of conifers. Products and services
from animal origin (furs, trophies, hunting) and berries, such as Vaccinium
spp. and medicinal plants are not included in this
Mushrooms, the reproductive structures of fungi (also known as sporocarps or fruiting bodies) are a major food item 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. Both natural and planted conifer forests are important sources of edible mushrooms world-wide.
The fungi are a large group of 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, causing disease in higher plants, as 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 derives benefits from the association.
The predominant symbiosis between fungi and trees takes place 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. The mycorrhyzal fungi basically function as an extension of the plant’s root system and are the normal 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 fungi produce highly favoured, edible wild mushrooms, which are harvested in large quantities. Of the several types of mycorrhizae, only fungi forming "ectomycorrhizae" (a type that forms a distinct fungal mantle around the exterior of the root tip) produce edible mushrooms (Molina et al. 1993). Some forest fungi, which are either parasitic or saprophytic, also produce edible mushrooms.
The conifers of the family Pinaceae have a large complex of mycorrhiza associates and some produce abundant and highly prized forest mushrooms. In the Pacific Northwest region of the United States and adjoining portions of Canada, the coniferous genera Abies, Larix, Picea, Pinus, Pseudotsuga and Tsuga are all known to have species of ectomycorrhizae associated with them. Douglas-fir, Pseudotsuga menziesii, for example, is known to have nearly 2 000 species of ectomycorrhizal associates (Molina et al. 1993).
A few of the common genera of ectomycorrhizae, which are associated with conifer forests and also produce edible mushrooms, include Boletus, Cantharellus, Craterellus, Suillis and Tricholoma (Molina et al. 1993). It must be acknowledged that the following review is not intended to be a comprehensive listing of species of edible mushrooms associated with conifer forests, but rather a description of some of the best known ones.
The Japanese matsutake mushroom, Tricholomamatsutake, ccurs in association with forests of Pinus densiflora in Japan, and is also found in Korea and northern China. This dark brown mushroom has a dense, meaty texture and a nutty (spicy) fragrant flavour that is highly prized by the people of Japan. It is available fresh from late fall to mid-winter and can be found only in Japanese markets or speciality product stores. Canned matsutake mushrooms are also produced. They can be cooked by a variety of methods including braising, grilling, steaming and frying. The Japanese matsutake is considered to be the most expensive food in the world. One hundred grams of good quality matsutake mushrooms sell in Japanese markets for as much as 10 000 yen (approximately US$80).
The indigenous matsutake mushroom is so popular in Japan that cultural measures, such as regulation of light to the forest floor, thinning and removal of understory vegetation, have been attempted to increase productivity (Hosford et al. 1995, Nishuda and Ishikawa 1967). Korea has recently become an important source of supply for the Japanese and there also has been an increased demand for the American matsutake mushroom, T. magnivelare (Pilz et al. 1997). The American matsutake is currently in such great demand in Japan that it can command a price as high as US$100/kg. Between 1989 and 1992, Japan imported 7 740 tonnes of T. magnivelare from various sources (Aguilar Hernández 1995).
Europeans, especially the French and the Germans, consume large quantities of chantrelles, Cantharellus spp. Declines in availability of chantrelles in Western Europe have spurned the growth of exports of Cantharellus spp. from Canada and the United States.
Edible forest mushrooms harvested from pine forests in Mexico are a traditional food. A recently conducted survey indicates that the species most frequently encountered in local markets were golden chantrelles, Cantharellus cibarius and king boletes, Boletus edulis. About 70 percent of the mushroom gatherers are women and children (Villarreal and Pérez-Moreno 1989a).
In India, several species of edible mushrooms harvested from conifer forests are locally important foods. These include the sporocarps of ectomycorrhizal fungi, fungi that can cause root disease, and wood decay (Table 9.1).
Flammolina velatupis a fungus that causes decay in Picea spp. and other trees is another highly prized mushroom in Japanese cuisine and is widely cultivated in Japan. This mushroom is also found in the Russian Far East where it is known as ilmak. This mushroom is easy to preserve by canning and is also sold dried (De Beer n.d., 1995).
Edible saprobes or parasitic edible conifer mushrooms include "Morchella", among the commercially most important ones.
Commercial harvesting of edible mushrooms increased significantly during
the 1980s in the Pacific north-west region of the United States and British
Columbia, Canada, and is currently a multimillion dollar industry with
several thousand tons harvested annually (Molina et al. 1993). The
increase is largely due to increased demand from Japan and Europe. Chantrelles,
and the American matsutake,
Tricholoma magnivelare, are the principal
species of economic importance. The American matsutake mushroom is, by
weight, the most valuable mushroom in the region after "truffles" (which
are edible fungi). Most of the crop harvested from the northern interior
of British Colombia, Canada, to northern California is exported to Japan
where it is considered a viable substitute for the Japanese matsutake,
matsutake (Hosford et al. 1995). Commercial harvesting of this
species is concentrated in forests of Pinus contorta (Molina
al. 1993). Other ectomycorrhizal mushrooms gathered in conifer forests
in this region include Boletus
spp., two species of truffles;
carthusiana and Tuber gibbosum and a species known as "hedgehogs,"
repandum (Amaranthus and Pilz 1996).
Edible mushrooms harvested from conifer forests in India
||Forest Type and Location|
|High elevation meadows in the Himalayas
Conifer forests (Himachal Pradesh)
Abies and Pinus forests
From bark of Cedrus deodara
Conifer forests (under snow cover)
Conifer forests (Uttar Pradesh, Jammu and Kashmir
At base of various conifers
Source: M.P. Shiva, Centre for Minor Forest Products, Dehra Dun, India.
Commercial harvesting of mushrooms in western United States is a relatively
young industry. A study conducted during 1992 indicates those mushroom
harvesters, processors and shippers had been in business for an average
length of nine years. Processors employed an average of five workers in
1992 and purchased from an average of 112 individual harvesters. An average
total of about 25 000 kg were harvested and the average value of purchases
per processor was US$278 000. A total of 1.78 million kg of mushrooms was
purchased by the industry in 1992. Of this total, more than half was purchased
from harvesters in western Oregon and Washington. The gross value of the
industry’s production for 1992 was estimated at US$41.1 million: US$25.1
for Oregon, US$11.9 million for Washington and US$1.6 million for Idaho.
This provided either full-time or part-time employment for nearly 41 000
people (Schlosser and Blatner 1995). Prices paid to pickers can vary from
US$6.50 to 100/kg depending on mushroom species and quality (Table 9.2).
Average price per kilogram paid to mushroom pickers
in the Pacific North-western United States - 1992
|American matustake, Tricholoma magnivelare
Golden chantrelle, Cantharellus cibarius
Boletes, Boletus spp.
Truffles, Leucangium carthusiana and Tuber gibbosum
Hedgehogs, Hydnum spp.
* Prices of up to US$100 were paid for young mushrooms of outstanding
Source Amaranthus and Pilz (1996)
In 1992 most of the edible mushrooms harvested in the Pacific north-west
were sold to international markets. Ninety one percent of the American
matsutake harvest was exported, mostly to Japan. Forty one percent of the
chantrelle harvest was sold to European markets and 30 percent was sold
in western United States (Schlosser and Blatner 1995, Table 9.3).
Key final markets as a percentage of the total volume of edible ectomycorrhizal mushrooms from conifer forests in the Pacific north-west, United States – 1992
|Edible Mushroom||Key Final Market||Percentage|
Germany and France
Other international markets
Source: Schlosser and Blatner (1995)
Until recently, most trade in edible forest mushrooms in Mexico was for domestic use. Between 1984 and 1987, there was a limited export, primarily to the United States, which totalled US$410 000 (Villarreal and Pérez-Moreno 1989a). However, because of the demand for the American matsutake mushroom in Japan, a vigorous mushroom industry has developed in Mexico since 1985 (Villarreal and Pérez-Moreno 1989b). In Mexico, the American matsutake mushroom is found in pine forests, principally Pinus tecote, and fruiting bodies appear during the rainy season between July and October. Commercial harvesting presently takes place in the States of Mexico, Hidalgo, Michoacan, Oaxaca and Veracruz. Potential distribution of this mushroom in Mexico includes Baja California de Norte, Chiapas, Chihuahua, Coahuila, Durango, Guerro, Guantuato, Jalisco, Nayarit, Nuevo León, Queretaro, Sonora, Tlaxacala and Zacatecas. Between 1989 and 1992, some 35.8 tonnes of American matsutake mushrooms were exported from Mexico to Japan. The 1993 harvest alone was 12 tonnes, yielding a return of US$375 000 to appoximately 3 000 families involved in the harvest. Japan imported 8.4 tonnes of that harvest for a value of US$465 000. Mexico’s participation in the Japanese mushroom market currently stands at 0.25 percent. Approximately 35 000 hectares have been designated as potential mushroom habitat in Mexico, but harvesting currently occurs on only 48 percent of the habitat. A potential annual harvest of 30 tonnes is projected from the States of Hidalgo and Veracruz alone (Aguilar Hernández 1995).
Japan places strict standards on the quality of American matsutake mushrooms that are imported into the country. Mushrooms must be plucked whole by hand and cleaned (Japanese will not buy matsutake that have been cut). They must be kept fresh and undamaged, be free of maggots and be stored at the proper humidity. Shipping occurs in storage containers kept at a constant temperature of 8o C from the collection point to the packing station and 4oC when shipped abroad (Villarreal and Pérez Moreno 1989b).
The mushrooms produced by the fungus Boletus luteus appear spontaneously (unintentional nursery inoculation or spores from nearby plantations) in Pinus radiata plantations in Argentina, Chile and Spain. The first fruiting bodies appear during the fourth year after planting and reach peak production in the seventh year. The yield then continues at a more or less constant level until the plantation reaches age 15 and the dense crown foliage prevents penetration of sufficient solar radiation to the forest floor (Ibqal 1993). In Chile, sporocarps of Boletus luteus develop in Pinus radiata plantations between the ages of 6 and 20 years. Yields between 0.3 and 1.5 tonnes/ha have been reported (Chandrasekharan et al. 1996). These nutritious mushrooms can be gathered by local people, dried in the sun to reduce moisture content down to 35 percent and are sold to exporters. Exports of sliced, dehydrated or preserved B. luteus and other mushrooms have been rising. In 1981, Chile exported 943 tonnes of this mushroom at a value of US$2 031 863. The primary markets were France, Peru and the United States with smaller quantities being exported to Ethiopia, the Netherlands, Italy and Switzerland (Iqbal 1993). Statistical data on exports of edible Chilean mushrooms (primarily from pine forests) for the years 1990-93 are given by Garfias Salinas et al. (1995) (Table 9.4).
Commercial harvesting of edible mushrooms, principally of the genus
in pine plantations became an important local enterprise in Ecuador during
the late 1980s. In Ecuador, pines are not native but plantations of exotic
pines occur in the altiplano between 2 000 and 4 000 meters above
mean sea level and presently cover approximately 30 000 ha. Most mushrooms
are sun-dried and shipped directly to supermarkets and delicatessens in
larger cities. In 1991, a commercial mushroom dehydration facility was
developed in the community of Salinas (Bolívar Province). However,
sun drying remains the primary means of processing the harvested mushrooms.
In 1993, some ten tonnes of mushrooms were harvested from pine plantations.
During the following year, production increased to 14 tonnes. Dried mushrooms
are packaged in commercial lots of 10 kg and sold for an average price
of US$5/kg. They are repackaged for individual sale in packages of 50 grams
and sold at an average price of US$0.50/package. Commercial harvesting
of mushrooms from pine plantations is now an important rural enterprise,
especially for women. Depending on location, fresh mushrooms can be sold
for up to 1US$/kg. Sun dried mushrooms sell for as much as US$2.00/kg (Rojas
and Mansur 1995).
Exports of edible mushrooms from Chile
1 153 148
1 591 263
3 212 540
1 228 799
3 236 925
5 030 097
2 197 331
2 123 662
1 505 197
5 826 190
3 029 621
1 383 146
5 322 730
Source: Garfias Salinas (1995)
Commercial harvesting of wild mushrooms from woodlots in the United Kingdom is still considered to be a small industry but in northern Scotland, Cantharellus cibarius and Boletus spp. are harvested in sufficient number to be shipped to south-eastern England and continental Europe (Slee 1991).
Poland is the largest European exporter of edible mushrooms and supplies 70 percent of the German market imports (Acker 1986).
In the Pacific north-west region of the United States, commercial harvesting of forest mushrooms offers seasonal income and supplemental income in areas where unemployment is presently high due to a depressed timber industry. However, the industry has caused some problems and concerns including (Acker 1986):
The state of Washington implemented licensing requirements for wild mushroom buyers and dealers in 1989. California recently stopped all mushroom harvesting, including recreational picking, in many state parks to help control habitat disturbance. USDA Forest Service is developing management guidelines for mushroom harvest and monitoring the resource for sustained productivity on National Forest lands in California, Oregon and Washington (Molina et al. 1993).
Extensive timber harvesting and mushroom picking has led to concern about the sustainability of the commercial wild mushroom harvest in the Pacific north-west region of the United States. There is additional concern that mushroom harvesting at high rates could lead to reduced forest health and productivity or affect food webs for wildlife species. Much of this concern comes from Europe where a decline in populations of mycorrhizal fungi has been observed over the past three decades (Amaranthus and Pilz 1996). A paper by Arnolds (1991), for example, provides evidence that in some European forests, ectomycorrhizal fungi are producing fewer sporocarps, notably in the oldest forests (more than 40 years old) and, in particular, conifers. He discusses a number of causal factors that might be responsible for this phenomenon including harvesting of edible mushrooms. He points out that, with the exception of Cantharellus cibarius, most of the species with declining numbers of sporocarps are not harvested for human consumption and concludes that there is no evidence to suggest that removal of sporocarps affects survival of the mycelia of ectomycorrhizal fungi. He also cites similar studies from Sweden, which have arrived at the same conclusion. He suggests that other factors such as air pollutants (SO2, NHx,), soil acidification and nitrogen eutrophication may be responsible for declines in sporocarp production.
In Mexico, there is concern that harvests of the American matsutake mushroom from Pinus teocote forests of the intensity experienced in recent years may be reducing the viable wild populations to the point of threatening their survival. In many areas, this species is now rare. Damage reportedly occurs when the basidiocarps (mushrooms) cannot release a sufficient number of spores to start new colonies before they are picked. The fungus mycelia are damaged by collection of the reproductive fruiting bodies and soil compaction. Conservation of this species requires retention of forest cover and a better understanding of the biology and ecology of this fungus (Villarreal and Pérez-Moreno 1989b).
In 1989, the Governments of the Mexican States of Hidalgo and Veracruz signed accords with Japanese importers and local mushroom harvesters in an attempt to ensure adequate conservation measures. The accord in Hidalgo was subsequently annulled, however, because of lack of due legal process. Some efforts are underway to train collectors about the best harvesting methods (Villarreal and Pérez-Moreno 1989b).
Another concern is the effect of thinning and other silvicultural operations on future yield of edible mushrooms. In north-western United States, dense, overstocked stands of Pseudotsuga menziesii, and Tsuga heterophylla which are in need of thinning presently yield high volumes of edible forest mushrooms. Studies are underway by research scientists of USDA Forest Service to estimate yields after thinning (Pilz et al. 1997).
Human societies throughout the world have made use of insects as an everyday dietary supplement, occasional delicacies and replacements for more common foods in times of shortages. In at least one instance, an insect that feeds on the foliage of pine is a traditional food source. The insect is known as the Pandora moth, Coloradia pandora. This insect occasionally reaches epidemic proportions and causes severe defoliation of Pinus contorta, P. jefferyi and P. ponderosa in western United States. Recently, there have been outbreaks of this insect in northern Arizona, southern California and central Oregon. To the people of the Paiute tribe of the Owens Valley/Mono Lake area of California, the larval stage of this insect, known as piuga, is a preferred food and attempts on the part of officials of the USDA Forest Service to control outbreaks with insecticides have met with stiff opposition from tribal people (Blake and Wagner 1987).
The pandora moth has a two-year life cycle. The adults appear in late June - early July and eggs hatch in August. The larvae feed on the foliage (Fig 9.1) and overwinter, as partially grown larvae, at the bases of the needle in the crowns of host trees. They can remain active during the winter months and feed whenever the days are warm and sunny. They mature the following summer and drop to the forest floor to pupate. The pupae remain in the soil for about one year, then emerge as moths to repeat the cycle (Furniss and Carolin 1977).
Figure 9.1: Mature larva of the pandora moth, Coloradia pandora. This insect defoliates several pine species in western North America and is a traditional food of the Paiute tribe of the Owens Valley - Mono Lake area of California, United States.
Every other year, during the second or third week of July, the Paiute people search for evidence of piuga around the base of large Pinus jeffreyi trees. Piuga trees are located by the presence of frass pellets (larval droppings) on the forest floor or raining down from the tree crowns. When the trees are located, the people return to their homes and wait for the larvae to mature. They return to the infested trees in early July to collect the mature larvae as they are migrating from the tree crowns to the forest floor to pupate. Collection of piuga is a traditional family activity that can last for as long as three weeks. The larvae are collected in trenches and are gathered by hand once or twice a day. The collected larvae are processed on site by roasting and drying. A mound of sandy soil is made and a fire is built on and around it to heat the soil. When the coals die down, the mound is opened and the live larvae are thrown in and mixed with the hot sand for 30 minutes to one hour. This effectively removes the setae (fine hairs) on the bodies of the larvae. The larvae are then sifted from the hot sand, washed, sorted and checked to see if they are properly cooked.
Dried piuga are stored in a cool, dry place where they will keep for at least one year and possibly for as long as two years. The dried larvae are prepared by boiling in plain or salted water for about one hour to soften their bodies. The aroma of the cooking larvae has been described as being similar to that of mushroom soup or scrambled eggs and mushrooms. The entire larva, except for the head, is eaten as a finger food. Many people also drink the broth and some use it to make a stew with vegetables and piuga. These larvae are considered to be a tasty, nutritious food that is especially good for sick people. A nutritional analysis indicates that they are rich in proteins (11.78 percent) (Blake and Wagner 1987).
Lichens are another example of a symbiotic relationship between a fungus and a green plant (algae). These unique plants are frequently associated with conifer forests. They grow on the branches and trunks of trees, on rocks or on the forest floor. Some species of lichens associated with conifers have been used as sources of natural dyes, others have been used for food. Lichens are currently harvested on a commercial scale for forage for reindeer, floral decorations and to simulate green foliage in architectural models.
Many species of lichens have been used as dyestuffs. Among the best known of dyes of lichen origin is orchil, which produces a range of vivid purple or magenta hues. This dye is derived from lichens of the genus Rocella, which grow on rocks along the Mediterranean coast, the Canary Islands, the Cape Verde Islands, India and Ceylon. Orchil was the most important lichen dye used by ancient and medieval dyers (Wickens 1983) and was also widely used as a fabric dye in Europe and North America during the eighteenth and nineteenth centuries (Adrosoko 1971).
Several lichens associated with conifers are also sources of natural dyes. The most widely used dye lichen in North America is the eye catching wolf lichen, Letharia vulpina, which commonly grows on Pinus spp. and other conifers (Figure 9.2). This lichen yields a bright yellow dye and was highly prized by the Chilkat Tlingit indians of coastal Alaska who traded commodities such as fish oil for wolf lichen to dye their intricately designed dancing blankets. These blankets are still worn by Chilkat dancers in their traditional performances (Sharnoff 1997). Old man’s beard, Usnea longissima, a common lichen associate of conifers in western North America, yields a yellow-grey to yellow-white dye. Lungwort, Lobaria pulmonaria, a lichen found either on Tsuga heterophylla or on rocks in south-eastern Alaska, United States, yields a yellowish-brown dye (Bliss 1981). The Coastal Salish tribes of Vancouver Island, British Columbia, used a dark-coloured filamentous lichens of the genus Bryoria as a source for a yellow dye (Turner 1977).
The use of a lichen known as black tree moss, Bryoria fremontii, by indigenous tribes of western North America is described by Turner (1977). This lichen is found from Alberta and British Columbia, Canada south, to Baja California, Mexico, with outlying populations in Colorado and the Black Hills of South Dakota, United States. Characteristically a dark coloured, filamentous lichen, it hangs from the branches of a number of conifers including Larix occidentalis, Pinus contorta, P. ponderosa and Pseudotsuga menziesii. This lichen was widely used as a food by indigenous tribes across British Columbia, Canada and portions of northern California, Idaho, Montana, Oregon and Washington, United States. Tribes that used this lichen for food included the Coeur d’Alene, Columbia-Wenatchi, Flathead, Kalispell, Spokane, Kitskau, Klamath, Kootenay, Lilloet and Nez Perce.
The most common means of preparing this lichen was to clean it, soak it in water and cook it in an underground-steaming pit lined with large, red-hot rocks. Layers of damp vegetation were placed over the rocks and the lichen was heaped on top followed by more damp vegetation and a thick layer of soil. Cooking often lasted two or more days.
Reports on the palatability of this lichen are mixed. When properly prepared, it is said to be delicious and was considered by some tribes to be a luxury food. Other reports indicate that it is rather tasteless and even has a soapy flavour. A more detailed assessment of its taste indicates that it has a bland flavour. Some tribes added the bulbs of nodding onion, Allium cernum or camas, Camassia quamash, to the lichen to give it more flavour. After European settlement, indigenous tribes added sugar or molasses. Elk and other large mammals also eat Bryoria fremontii. Cattle have been known to feed on it during times of scarcity of other forage.
A closely related species, Byroria tortuosa,occurs in the coastal regions of western North America. This species contains vulpinic acid, has a bitter flavour and can be poisonous. In areas where the ranges of the two overlap, local tribes were well aware of the difference between the two species.
Figure 9.2: The wolf lichen, Letharia vulpina, is a traditional source of yellow dye for the Tlingit Indians of Alaska.
Harvesting of the lichen Cladonia stellaris, a species that is a frequent associate of Pinus sylvestris, is done on a commercial scale in three Nordic countries: Finland, Norway and Sweden. Primary uses include forage for reindeer, an addition to floral arrangements and as simulated foliage in architectural models (Kauppi 1979, 1993). In Germany, branches of Larix decidua covered with lichens are a popular speciality product (Ehlers 1968).
Total exports of C. stellaris from the three Nordic countries in recent years totalled 2 000 tonnes, annually. Since 1988, Sweden has exported more lichen than Finland, but the Finnish product is more valuable. Finnish exports alone peaked in 1970 with 2 000 tonnes then fell dramatically to less than 1 000 tonnes in 1974 and, since 1987, to less than 500 tonnes. Reductions in harvest are the result of reduced foreign demand accompanied by a fall in prices. Germany is the principal market for exports of Cladonia stellaris and receives 83 percent of the total harvest from the three Nordic countries. Denmark is a distant second and receives about 10 percent of the harvest (Kauppi 1979).
In Finland, the lichen processing industry is centred in Oulu. In Norway, Lillehammer is the centre of lichen production and the Swedish lichen industry is centred in Sveg. The lichens are collected between May and November. Most of the material is dried into easy-to-handle blocks and packed into transport trays. Moist lichens are exported only in autumn and comprise about ten percent of the total crop. Annual income from lichen in a productive forest is usually greater than the value of timber from the same forest (Kauppi 1979).
The commercial harvesting of lichen in Finland began in 1910 and national regulation, in the form of laws controlling exports, began in 1931 (Kauppi 1979). In Finland, decorative lichens are considered to be the property of the landowner, unlike berries and mushrooms that are considered public property (Saastamoinen 1984). As of 1979, the level of employment in the Finnish lichen industry was estimated at 500 people working full time for five months of the year. Additional workers are employed temporarily during the summer when school is not in session. About 8 000 person-days are required to harvest and process the Finnish lichen crop. People on the island of Hailuoto, off Oulu, derive one-third of their income from harvesting of lichens (Kauppi 1979, 1993).
Problems associated with maintaining the sustainability of lichen harvesting include site deterioration from over-harvesting, clearcutting, gravel quarrying and trampling. Research studies show that only about 20 percent of the lichen should be harvested at any one time and picking should be at five to six year intervals in any one area (Kauppi 1979).
Studies in Norway indicate that commercial harvesting of Cladonia spp. in Pinus sylvestris forests can have a variety of effects. Pine regeneration tends to be more prolific on sites where lichens had been removed or thinned. On dry, exposed sites with coarse soils and more rapid water loss, removal of lichen results in added evaporation of soil moisture and reduces tree growth. On sites characterized by fine textured soils, removal of lichen has no effect on tree growth. This study concludes that while the high export value of lichen makes joint production of wood fibre and lichen a highly desirable operation, the harvesting of a speciality product can affect other forest resources (Aakre 1966).
Dwarf mistletoes, Arceuthobium spp., are parasitic plants that infect many conifers of the families Pinaceae and Cupressaceae. They cause growth loss, deformity and, in extreme cases, tree mortality. Most dwarf mistletoes are found in North America (western Canada, Mexico and western United States) but several species occur in Central America, the Caribbean, the Mediterranean Region of Europe and Northern Africa, eastern Africa, the Near East and Asia (Hawksworth and Wiens 1996).
A number of traditional uses of dwarf mistletoes have been documented and are summarized by Hawksworth and Wiens (1996). In northern Maine, French and English women used twigs of spruce, Picea spp. infected with Arceuthobium pusillum in their hair at the mid-winter festival and ball. There is no established linkage between this custom and the European tradition of hanging a sprig of mistletoe, Viscum album, over a doorway at Christmas. Young women of the Okanagan and Colville tribes of British Columbia, Canada and Washington, United States, boiled branches of Pseudotsuga menziesii infected with A. douglasii to make a hair wash that they believed gave them long and thick hair. The indigenous tribes of California, United States prepared a decoction of A. occidentale, a parasite of Pinus sabiniana, (Fig 9.3) to treat stomachache. An undetermined species of Arceuthobium was used by California natives for treatment of haemorrhage of the lungs and mouth, tuberculosis, emaciation, stomachache, cough, colds and rheumatism. The Bella Coola natives of coastal British Columbia, Canada, used shoots of A. tsugense and the Navajos of New Mexico and Arizona, United States, used both A. divaricatum and A. vaginatum in the treatment of several illnesses.
Figure 9.3: Aerial shoots of the dwarf mistletoe, Arceuthobium occidentalis, a parasite of Pinus sabiniana. This plant was used for medicinal purposes by indigenous tribes in California, United States.
Dwarf mistletoes have also been used to treat a variety of illnesses in Mexico. A. vaginatum has been used for treatment of cough in Veracruz. Indigenous people living in the vicinity of Tepehuanes, Durango State, used a decoction of A. vaginatum for treatment of rheumatism and lung disorders. A. globosum was used for the treatment of diarrhoea and nervous, pulmonary and lung disorders. A. globosum has also been burned as incense in religious ceremonies in Mexico but the basis for this practice is not known.
The dwarf mistletoe, Arceuthobium oxycedri, (Fig 9.4) infects a number of species of Juniperus across its natural range from the Mediterranean Region of Europe and North Africa, to the NearEast and Asia. The shoots of this plant are highly nutritious and are reportedly collected and used as fodder for goats and sheep in Turkey and Pakistan (Ciesla 1993, Zakaulla and Badshah 1977) and Turkey (Actaay 1954). Acatay (1954) expresses concern that in Turkey this practice is damaging because infected trees are felled. Zakaullah and Badshah (1977) report that in the Province of Balochistan, Pakistan, shepherds usually cut mistletoe infected shoots of juniper for feeding their animals at the site or they may carry them to their hamlets in the forest. They suggest that the latter practice, if done during the period when the fruits of the dwarf mistletoe plants are mature, could introduce this damaging parasite to new areas.
Figure 9.4: Dwarf mistletoe, Arceuthobium
oxycedri infections on Juniperus excelsa, Balochistan Province, Pakistan.
The shoots of this parasitic plant are gathered by herdsmen as food for