8 Forest Farming Practices
Deborah B. Hill
University of Kentucky
Louise E. Buck
Ithaca, New York
Humans have used forests for shelter, food, water, body coverings and living space since before the beginning of recorded time. In many parts of the tropical world today, indigenous peoples still depend on forested lands almost exclusively for their entire way of living. In addition to timber, most forested systems can produce basketry materials, bee products, botanicals, carving and crafts materials, fruits and nuts, fencing materials, fuels, medicinals, mushrooms, oils, resins and saps. Individual species from which these products can be derived differ, but the categories remain constant. Traditionally in temperate climates, people have gathered what they needed from the forest, but have not necessarily farmed the forest in the sense of actively changing what they found there to create or increase quantities of desired products. Agroforestry practices in general differ from standard forestry and agriculture practices through the four "i"s - they are intentional, integrated, intensive and interactive. The practice of forest farming, is the intentional manipulation of forested lands to produce specific products, most specifically food or medicinal products, although other non-timber forest products are also possible. In contrast to other agroforestry practices, such as alley cropping or silvopasture, where trees are introduced into some type of agricultural system, in forest farming, agricultural or cropping techniques are intentionally introduced into existing forested systems.
Since the beginning of the twentieth century when forest management was formalized in the United States through the efforts of President Theodore Roosevelt and his first head of the newly established Forest Service, Gifford Pinchot, it has been the intention of government agencies to manage federally-owned National Forests for "multiple use" (formulated into law with Public Law 86-517, Multiple-Use Sustained-Yield Act of 1960). This usually meant a combination of management for timber, water resources, wildlife habitat, and recreation. Although "multiple use" management emphasized the long-term sustainability of any management practices on the National Forests, it rarely considered the possibility of utilizing public lands for non-timber, or what are currently referred to as "special forest products”.
Private forest lands were held by corporations primarily as sources of timber supply, and by individuals for a variety of reasons, among which timber ranked relatively high because of its economic potential. Nonindustrial private forest landowners kept and perceived their forest lands as "free goods" - there for the owners' use but, in the vast majority of cases (approximately 95%), without any kind of professional management plan (Baughman, 1996). In early North American settlements and currently in more isolated or rural parts of much of the United States, local people used forests for obtaining honey, maple syrup, mushrooms, fruits, nuts and berries. They also collect various botanicals and medicinal plants, vines for decorations or basket making, burls for carving, certain rot-resistant species (e.g. redcedar (Juniperus virginiana L.), and black locust (Robinia pseudoacacia L.)) for fenceposts, and anything dead or down for fuel. These are all "passive" uses. For many of these categories, it is possible to harvest the desired products on an annual or other regular basis - time horizons shorter by many decades than those required for timber production, even with an existing forest aged 40 or more years. In tropical forests today, economists are just beginning to realize that the annual harvest of so-called "extractive reserves" - nuts, fruits, rubber, etc., yield greater per hectare incomes than a single timber harvest of the same area for teak, mahogany, and other high-value tropical woods, while also leaving the integrity of the rainforest and its fragile soils intact.
The gathering of mushrooms, berries, greens and sometimes forest floor materials (e.g., pine straw for landscaping) has been traditional for at least individual uses in forested lands in the British Isles, Scandinavia, and many countries in Western and Eastern Europe, as well as in parts of Asia, India, Africa, and Latin America. Much of this activity has been on an individual, as opposed to a commercial, basis and has also been allowed on forested lands more or less regardless of ownership. Other countries are increasingly aware both of the commercial potential for these special forest products as well as the ecological dangers from overharvesting or overexploitation. Having occupied their lands for centuries longer than Europeans have lived in the Western Hemisphere, there is concern about long-term sustainability of wildcrafting or gathering and awareness of the need for forest farming to enhance production of many special forest products (Gupta, 1982; Jappinen et al., 1986; Glowacki, 1988; Kujala, 1988; Franz, 1991; Belonogova, 1993).
In North America, demographic data for the northeast and midsection of the United States indicate that more than 70 percent of the commercial timber land is owned by nonindustrial private forest landowners. In Kentucky, for example, 93 percent of those lands are in private hands, the average forest land holding is10 ha, and 60% of the owners hold 4 ha or less of forest land. Farm economies have suffered severely in recent years, and farm ownerships - including their forest lands - are being continually fragmented from one generation to the next, partly because of division of lands for different members of the family and partly because of property and inheritance taxes. These forces are encouraging landowners to seek ways to make their forest lands more economically productive, which currently means cutting timber. On small ownerships, however, it is often not economically practical to log commercially in any way other than clearcutting. Forest farming offers many options, none of which alone is able to provide a family income, but two or more of which may, together, provide substantial supplementary income. As in the tropical example above, products from forest farming activities can yield annual income and cash flow while leaving the forest ecosystem relatively undisturbed and able to continue its crucial benefits of water conservation, soil erosion control, microclimate amelioration, and oxygen production (Pilarski, 1994).
North American forests, especially east of the Mississippi River, have been harvested for timber at least twice in the past two centuries. The historic pattern of cutting has been "high-grading" - i.e., cutting the largest and most valuable trees. This cutting pattern is analogous to slaughtering the best animals in a livestock herd, or removing the best producing agronomic crops along with their seeds. What is left behind are the weakest, least desirable, least productive stock to carry on. In eastern North America, forests regenerate relatively rapidly, often with opportunistic and less commercially valuable species than existed in the original forests. The second-growth forest will likely be composed of "pioneer" species which are programmed to regenerate after disturbance, and of sprouts from the timber that was cut, as well as some small diameter advanced regeneration of indigenous species. Stump sprouts contain the genetic strain of good timber species which were removed, but emerge in multiple stems, none of which (without appropriate management) will have the equivalent commercial value of the parent tree.
Native forests have been impacted by humans for centuries. Native Americans harvested timber on a minor scale, and used fire to control understory vegetation and enhance their hunting opportunities. More recently, these forests have also been impacted and disturbed by other factors - natural events such as earthquakes, landslides, windstorms, ice storms, insect and disease outbreaks, as well as such human factors as surface mining, agricultural clearing, urban and suburban development, and to logging. The forests that occupy the land today thus are far different from the ones seen by early European settlers - less diverse in tree, shrub, and herbaceous plant species as well as in wildlife species ranging from soil organisms to large game animals and predators. If left to itself without further human disturbance, the forest would eventually - over centuries - achieve a different climax stage similar to its original state (different, for example, because of permanent loss of significant species, such as American chestnut (Castanea dentata (Marsh.)Borkh). which, until its untimely demise in the 1920s and 1930s from an exotic fungal disease, comprised 20% of the mixed mesophytic forest of the Appalachian region).
To achieve a healthier forest in a more human time scale, it is necessary to manage forests in such a way as to encourage more diverse and economically desirable tree species of the original forest types, and to remove trees from the existing forests so that the residual forest is increasingly a stronger, healthier and more diverse forest than existed when management started. Foresters refer to this kind of management as timber stand improvement (TSI). Forest farming can be incorporated into TSI by judiciously removing individual trees or species to foster the production of one or more forest-farmed products. Standard silvicultural practices, such as prescribed burning in early or mid-rotation and harvesting practices such as shelterwood or selection cuts (providing the latter do not constitute high-grading) at the end of the commercial timber rotation, may also enhance the economic value of the forest. This value comes from the timber products themselves and benefits derived from alteration of soil moisture, and species mixtures (i.e., forest farming crops) that have greater economic value (Schlosser et al., 1992).
Forest ownership and management differences exist in various parts of North America. We have noted above that forest ownership in the eastern and midsections of the United States is primarily in the hands of individuals. In the southern part of the country, a higher proportion of forest lands is held by private corporations, and the natural forest types are more coniferous. In the Pacific Northwest and in much of the northwest quadrant of the United States, more than 50%, sometimes more than 75%, of the forested lands (again, predominantly in coniferous forest types) are publically owned, by the United States Department of Agriculture's (USDA) Forest Service and the Department of the Interior's (USDI) Bureau of Land Management and National Park Service. Many forested lands in the west are also owned by Native American tribes or by the states (state trust lands). All forested lands would benefit from management which would upgrade their current quality, but different ownerships have quite different management goals and incentives. Forest farming activities are probably least likely to occur on forested lands owned by private corporations. Managers of publicly owned lands, however, are becoming increasingly interested in forest farming options because of public pressures to de-emphasize timber harvesting on public lands.
Another aspect of forest farming is the three dimensional (vertical, horizontal, and below ground) intentional plantings called forest gardens. This form of management, usually implemented on small areas of land (< 2 hectares (5 acres)), may begin with native forest trees, especially ones that produce fruit, nuts or sap for syrup. The classic model is multi-storied and emphasizes companion plantings of all species involved, especially nitrogen-fixing plants and herbaceous plants known to resist or repel harmful insects. A forest garden may contain as many as seven different stories, including plants that may be most useful for their roots. These stories are:
canopy - full size fruit or nut-producing trees
low-tree layer - fruit and nut trees on dwarfing rootstocks, bamboo
shrub layer - currant and berry bushes
herbaceous layer - medicinal and/or culinary herbs and perennial vegetables
ground-cover layer - creeping plants such as some Rubus species or cucurbits
rhizosphere - shade-tolerant and winter root plants
vertical layer - climbing berries, nasturtiums, runner beans and vines, trained up trees, over fences or sheds.
This type of intensively managed small "forest" is typical of many parts of the world, notably the tropics, and can support most of the food needs of up to ten people on less than 0.4 ha of land. When appropriately constructed and managed, forest gardens are able to produce some form of fruit, vegetable, or herbal food for a longer than normal growing season in temperate climates. Robert Hart, in his book Forest Gardening (1991), states that this type of forest farming also embodies several basic forest ecosystem principles or processes:
maintenance of water circulation and total recycling
non-disturbance of the soil and continuous soil cover
attraction of and provision of shelter for wildlife.
Once properly established, forest gardens can be virtually self-maintaining, and, with attention to selection of appropriate plant mixtures, may be essentially pest insect- and disease-free. Materials from weeding or pruning operations are cycled back into the practice through composting.
The focus of this chapter is on three principal options for forest farming - medicinal herbs, edible native and exotic mushrooms and bee products. Each is concerned with a variety of specific products and applicable to most regions of North America. Market prices for products in each category tend to be steady or rising, thus there is room within the emergent industries for expansion of production by enterprising forest owners. The three types of practice have different forest management requirements. Management design options include, but are not limited to, intercropping, removal of small diameter hardwoods during TSI for mushroom production, and companion planting of herbaceous medicinals (e.g. American ginseng (Panax quinquefolium L.)) with high value tree species such as black walnut (Juglans nigra L.) or sugar maple (Acer saccharum Marsh.). The principal forest management requirement for apiculture (and for maple syrup production) involves crop tree selection and possible thinning to increase crown size for bee forage or sap production. Medicinal herb production normally involves cultivating the forest floor, and may also involve thinning the canopy to create the appropriate microclimate. An important concern for any of these practices is the use of chemicals in the production of either the tree crop or the farmed crop. Any proposed chemical must be compatible for all components (i.e., animal and plant) in the practice.
FLORAL, FRUIT AND NUT CROPS
Prior to discussing the farming of medicinal herbs, mushrooms and bees, several product options that also hold promise for being produced in forest farming practices will be identified. These include greenery and other floral products, forest botanicals such as foods and flavorings, and berries, wild fruits and nuts (Thomas & Schumann, 1992). The interested reader is encouraged to explore these opportunties further through the references provided as well as the growing networks of practitioners and professionals who are attempting to tap and advance this potential. Studies, conferences and discussion groups have begun emerging all over North America to focus the expanding interest in special product-based agroforestry to capture its economic and environmental potential for local income generation and sustainable development. Sufficient interest in special forest products sparked the multi-agency and organization sponsorship of the first North American Conference on Enterprise Development Through Agroforestry: Farming the Agroforest for Specialty Products in 1998, organized and hosted by the Center for Integrated Natural Resources and Agricultural Management (CINRAM, University of Minnesota).
Greenery and Other Floral Products
Commonly harvested products for the floral market in the Pacific northwest include plants such as beargrass (Xerophyllum tenax (Pursh.) Nutt.), sword fern (Polystichum munitum (Kaulfuss) K. Presl.), evergreen huckleberry (Vaccinium ovatum Pursh.), mosses (sheet moss, angel hair moss and antler moss), salal (Gaultheria shallon Pursh.) and scotch broom (Cytisus scoparius (L.) Link). Baby’s breath (Gypsophila paniculata L.), holly (Ilex spp.) and the boughs of many evergreen tree species also are widely harvested. This “wildcrafting” of forest lands has become a multimillion dollar business within the past five decades (Schlosser et al., 1991; Schlosser & Blatner, 1995). The lands harvested for these products may be either publicly or privately owned, although in the Pacific northwest the vast majority of the lands are publicly owned. Access rights are normally secured through lease or permit arrangements. Most of these products are harvested from public lands by members of several different (and competing) ethnic groups, among them southeast Asians, Native Americans and Hispanics. The seasonal harvesting of these products has an important impact on local economies. The economic value of several of these products is creating both an economic boom and considerable conflict in the area. Continuity of the resource and sustainability of harvesting are both in question if current practices continue. In the upper midwest birch (Betula spp.), ironwood (Carpinus caroliniana Walt.) and alder (Alnus spp.) tops are commonly collected. Grapevine (Vitis spp.), grasses and dried seed from many regions of the country also represent entrepreneurial opportunities.
Markets have been steady or increasing for many floral, greenery, and transplant products, with the success of the floral trade business depending on diversity and avoiding over-dependence on seasonal items (Schlosser & Blatner, 1989). While there is potential for cultivating many of these lucrative products on private lands, not enough is known about specific cultural techniques including the control of diseases. Optimal conditions relating to the successional stages of different western forest types for production of such products as beargrass and sword fern are known and could be implemented on private lands. It is a greater challenge to convince managers of federal agency lands to adjust their forest management plans to retain more forests with some canopy cover. Using such techniques as three-entry shelterwood cuts and thinnings, the production of several floral green products can be enhanced within 5 years (Schlosser et al., 1992; Schlosser & Blatner, 1997).
Forest Botanicals as Foods and Flavorings
In addition to their herbal medicinal qualities, forest botanicals are often prized as food and flavoring products. Herbs are used as seasonings and as ingredients in teas, coffees and soft drinks. Forest botanicals used as natural food preservatives are expected to become more important in the future, as are edible greens, roots, tubers and flowers that enhance the appearance of foods. Thomas and Schumann (1992) list many familiar edible wild plants throughout the country that have particular agroforestry potential. Some are considered rare delicacies capable of commanding high prices. Miller (1985, 1988) is a good source of information on plants that have commercial potential for wildcrafting and possibly forest farming.
Berries, Wild Fruit and Nuts
Native fruit trees and shrubs that grow in forest environments have considerable potential for understory cultivation in agroforestry practices as new markets for specialty native varieties open up. Wild or lowbush blueberries (Vaccinium angustifolium Ait.), huckleberries (Vaccinium membranaceum Dougl.) and Mayhaws (Crataegus spp.) are among the wild berries and fruits that have already been utilized by rural entrepreneurs (Thomas & Schumann, 1992). Blueberry picking has a high recreational value. Managing for berry production may include prescribed burning. Forest owners have developed interest also in “rescuing” more obscure species of wild fruits and berries through cultivation in forest practices, and research organizations are beginning to take notice of the potential for improving cultivars of shade-loving fruits and berries (C. Feldhake, 1997, personal communication).
Nut trees can be dominant in forest farming practices of the midwestern and eastern states, and TSI can readily foster the improvement of nut tree performance. The high protein value and food energy of most nuts, plus their versatility in cooking and excellent taste make them valuable for personal consumption even when commercial production is not feasible. Acorns from more than 60 species of oak trees, beechnuts (Fagus grandifolia Ehrh.), black walnuts, butternuts (Juglans cinerea L.), chestnut (Castanea mollissima Bl.), hazelnut (Corylus americana Walt.), shellbark hickory (Carya laciniosa (Michx. f.) Nutt.), shagbark hickory (C. ovata (Mill.) K. Koch), pecans (Carya illinoensis (Wangenh.) K. Koch) and pine nut of the Colorado piñon (Pinus edulis Engelm.) and the singleleaf piñon (P. monophylla Torr.& Frém.) are among the most favored and widely distributed edible nut trees in the US. Apart from black walnut there is little or no commercial foraging of native American nuts at present. However, the strong market for black walnut kernel and shell (there are over 300 grades of abrasives made by the Hammons Products Company in Missouri) signals possibilities for developing and expanding markets for other species. Considerable information has been developed in recent decades concerning the roles of nut trees in agroforestry practices, following Smith’s (1953) vision of a nut tree-based agriculture for marginal lands which is often credited as the conceptual foundation for modern agroforestry.
Many forest botanicals are used in the manufacture of medicinal compounds including a large number of herbs used to make teas, oils, powders and other products that are alleged to have curative or therapeutic effects on various common ailments. Medicinal properties of plants in forest ecosystems may be found in the leaves, roots or bark of trees or shrubs, or in the leaves, berries, or fruits of herbaceous plants that tolerate shade well. However, the greatest revenue derived from plants for medicinal purposes most often is from the roots.
Some forest-based medicinal products have long-established markets and represent an on-going economic opportunity for harvesters or growers. Medicines from forest plants were used by indigenous people of North America long before European settlers arrived, and have been depended upon in various countries of Asia for millennia. Certain of these have been actively traded through international markets for centuries. In the United States, the commercialization of medicinal plants expanded near the turn of this century, then diminished following World War II when synthesized pharmaceuticals came into prominent use. During the past two decades, as consumer interest in preventive health care and natural remedies has soared, markets for numerous plants reputed to have medicinal properties have re-opened or grown. Medicinal herbs that have achieved the greatest notoriety and value include many that inhabit forest environments of North America. Income opportunities for collectors of these plants thus have proliferated, as has the number of harvesters. Problems of scarcity and over-exploitation of highly-valued wild plants inevitably threatens the sustainability of these activities. The situation creates new opportunities for woodland owners to cultivate some of these plants on a profitable basis.
Throughout the world there are hundreds of plants whose roots are used for medicinal purposes, and North America is a major buyer and user of many. In 1907 the US Bureau of Plant Industry recognized fifty official root drugs in the US, whose underground portions were important commercially, but excluded roots that were used solely for their bark or resins (Henkel, 1907). Thirty of these were native to forested environments. Presently, the most valuable medicinal roots of North America are American ginseng and goldenseal (Hydrastis canadensis L.), followed closely by purple coneflower (Echinacea purpurea (L.) Moench) which grows better in a prairie setting than in a forest environment. Additional botanical roots that have been in demand by the drug trade and inhabit forests are listed in Appendix 8-1A.
The USDA’s well known handbook, Income Opportunities in Special Forest Products (1993) lists some of these and other forest botanicals that have forage potential for their medicinal qualities, emphasizing that the list is inevitably incomplete. Regional inventories of forest botanicals with medicinal potential have been conducted (Mater, 1994) and the characteristics of most of these plants have been described (Duke, 1985; Prescott & Prescott, 1986; Moerman 1986). Only a few, however, are known to have been cultivated. These include American ginseng, goldenseal, echinacea, black cohosh (Cimicifuga racemosa Nutt.), blue cohosh (Caulophyllum thalictroides Michx.) and bloodroot (Sanguinaria canadensis L.). Presumably, there is value in exploring the potential for cultivating any of the forest botanicals in agroforestry practices that are foraged and subject to over-harvesting.
The conservation of herb resources has been identified by the World Health Organization as an important issue (Akerele, 1991). Rather than relying on wild harvested supplies of some medicinal plants the world will have to learn to cultivate them in the future. Of the 70 indigenous medicinal plant species that are commercially harvested in the US, there are no data to support the extent to which they can be harvested on a sustainable basis. Studies are needed on reproductive biology, population dynamics, propagation and cultivation methods to remedy this knowledge gap.
In market terms it is useful to differentiate medicinal herbs from botanicals that possess specific chemistries of interest to manufacturers of pharmaceutical drugs. Experts speculate that demand for plants that have desired pharmaceutical compounds may in the future become more important than demand for herbal medicinals. To date, however, despite the unprecedented “green wave” of lay interest in herbs and natural plant medicines, there has been little research in the US in the field of phytopharmaceuticals, or plant drug preparation. Unlike Germany, for example, where plant drug research and development is flourishing, and new plant constituents are continually being introduced into the market by a relatively large number of manufacturers, the US is proceeding slowly due to a traditional regulatory system and the high cost of bringing such drugs to market (Mater, 1994). Under consumer pressure, the situation may change, thus opening markets for a variety of specific plant products. Plants for the pharmaceutical industry are likely to be produced under comparatively regulated, contractual conditions. In the foreseeable future, the main opportunities for landowners lie in cultivating herbal medicinals both for export and for sale in this country, not through pharmacies as they used to be, but through health food stores and similar outlets. The immediate popularity of Duke’s (1997) “Green Pharmacy”, which elaborates the healing power of herbs for numerous ailments and instructs readers in their preparation and use, provides a sense that herbal medicine may be becoming mainstream and indeed supplies will need to increase.
Word of mouth inquiry will normally lead growers or prospective growers to knowledgeable and reputable dealers. In certain states and regions, traditional trapping and fur trading companies are the principal buyers for herbal botanicals as well as numerous other forest products. In other areas, buyers are more specialized, dealing in one or a few products only and are more likely to have direct links with international traders. Natural products companies are beginning to form or expand into new regions of the country to capitalize on the potential for cultivating herbal medicinals, and gain better control over the quality of the products they sell. When possible, the herb companies tap into local networks of producers and traders and thus can be a good route for learning about the experience of other growers in a region.
Although product demand and price trends are generally upward, markets can be volatile on a seasonal basis as numerous actors in a distant, international arena pursue their various strategies within an industry that has traditionally harbored a notable element of secrecy. For certain medicinal plants, such as ginseng, that are regulated to control over-exploitation, state agencies maintain statistics that can help in monitoring market trends. These are sometimes considered by dealers to be of dubious value, however, due to problems of under-reporting, double-counting and other limitations of inadequately designed and staffed regulatory programs. Several states are in the process of re-writing their protected plant species control legislation to address these and related concerns.
Forest-based medicinal plant cultivation practices can be designed in various configurations. Existing stands of trees can be intercropped with understory plants. Tree cover can be altered - shade added or removed - to benefit herbaceous plants. Or new practices can be implemented by planting annual or perennial medicinals and trees together provided that the young trees can provide adequate shade for understory plants that require it.
Similar to other agroforestry practices, an important design objective is to ensure the compatibility of the tree with the understory crop. Specifically, resource competition for light, nutrients and moisture need to be minimized and allelopathic (toxic) effects avoided. Possible complementary interactions between upper and lower stories of the practice should also be considered. For example hydraulic lift, the process whereby water absorbed by the deep roots of trees and shrubs during the day passes from the shallow roots into the drier shallow soil at night (Dawson, 1993), in sugar maple trees can have beneficial moisture as well as nutrient effects on certain understory plants, particularly under drought conditions. Mayapple (Podophyllum peltatum L.) is an herbaceous medicinal root plant that has been demonstrated to take advantage of hydraulically lifted water from sugar maple roots. Other herbaceous plants that are believed to benefit from hydraulic lift include false Solomon’s seal (Smilacina racemosa (L.) Desf.), early meadow rue (Thalictrum dioicum L.) and wild strawberry ( Fragaira virginiana Duchesne), and possibly even American ginseng.
Important management issues to consider in planning or evaluating relations between plant components in forest-based agroforestry practices include tillage, density and intensity of cultivation, condition of the canopy, and the seasonality of key operations. Basic cultivation factors such as soil amendments and disease control should be decided on the basis of possible interactions between woody and herbaceous components. To approximate most closely the growing conditions of wild plants, tillage should be kept to a minimum, limited perhaps to scratching the top surface layer of soil to make it receptive to seed, roots or cuttings. When synergistic associations between the native tree population and the herbaceous understory are suspected, as, for example, the case with sugar maple and American ginseng, it is especially important not to interfere with this relationship. Extensive tilling will disrupt the fine, upper root system of the maple stand, limiting the possibility for the herbaceous plant to benefit from the hydraulic lift action of the maple. A minimum or no-tillage approach is feasible and often preferable when environmental conditions favoring the native plant exist. The presence of indicator species as well as the plant of interest can help in making this assessment.
Whether and how much to till the forest soil, or to establish tilled, raised beds on the forest floor depends much on the desired density of planting. For high density plantings, raised beds are generally preferable to continuous cultivation of the forest floor. Beds not only provide better control over cultivation operations, but also help minimize disturbance of the forest understory, assuming they are either widely dispersed or closely clustered, leaving opportunities for natural regeneration. The roots of many of the medicinal plants of interest are subject to fungal diseases, including root rot, damping-off, and blight. The potential for various fungi that are in the soil to infect the plant with one of these diseases is higher when nutrient requirements are unmet, or excessive moisture is present due to poor drainage. Under low density operations, the early detection of these diseases can limit their effect to one or just a few plants that can readily be removed -- under high density conditions, diseases are far more likely to ravage entire populations quickly. Therefore, as a basic disease prevention strategy, a cautious approach should be taken in decisions on planting density. Specific spacing strategies should be planned, based on the species and environmental conditions involved, and carefully monitored by the grower, as site characteristics are highly variable and experience-based knowledge is limited.
Once a fungal disease infects root crops, it can be difficult to eradicate. Topical treatments using the few chemicals that may have been approved for specific plants can be effective on a limited area, though for certain species there may be no authorized treatments. Once a broad area is infected, the only “sure” way to eradicate the fungal agent may be to fumigate it. While it is sometimes possible to obtain approval from regulatory agencies to use an eradicating agent in order to save an economically valuable crop from destruction, this measure is likely to negatively affect the regeneration potential of the forest. Presuming that sustainable management of forest ecosystems is a goal of forest farming, agroforestry “pioneers” should avoid the regular, widespread use of fungicides, herbicides or pesticides in the forest. An organic-oriented approach is probably more feasible in northern, drier climates than further south where warm temperatures and high humidity are regularly present.
While some herbal medicinals hold immediate opportunities for more intensive cultivation, they tend to be species whose active properties are not in their roots. Witch hazel (Hamamelis virginiana L.) and bittersweet (Celastrus scandens L.), for example, have been cited as two forest species in high demand that could be easily cultivated in intensively managed settings (Mater, 1994). Among root crops, there appears to be wide variation in their susceptibility to fungal disease. Ginseng, for example, is more vulnerable to root rot, blight and damping-off than goldenseal, and requires wider spacing. This spacing treatment should also result in a more valuable, natural-appearing root.
Canopy management should be considered with respect to the needs of both the upper and understory components of a practice. Again, examining relationships between American ginseng and sugar maple it appears that treatment for optimizing the sugar content and sap-producing potential of the maple simultaneously satisfies the shade requirements of the ginseng. The 75-90 percent shade needed by ginseng from a hardwood overstory is met when the maple stand is thinned to enable maximum crown development of each sap-producing tree.
The seasonality of labor and management requirements for the upper and lower story components must also be considered in designing a forest farming practice for herbal medicinals. The major tasks associated with the root crop involve seed or root collection and treatment, planting, harvesting, and drying. Generally, roots of annual plants should be dug just before flowering, and those of biennial or perennial plants late in autumn or early in spring. The object is to collect them when there is a cessation of growth. Besides shrinking more and weighing less if collected during the growing season, such roots are also likely to be deficient in medicinal properties (Harding, 1972; Koehler, 1912). Cleaning and thoroughly drying the root is another important task for assuring quality and good prices. Roots are dried by spreading them out in thin layers on racks or shelves. Thoroughly dried roots snap readily when they are bent and require from three to six weeks to cure, depending on weather and the character of the roots.
For most perennial root crops including American ginseng, seed collection and treatment, planting and harvesting operations are all conducted in the fall. Late fall, extending into winter is normally the best time for TSI activities. For maple syrup production, labor is required in the early spring. Thus, using a labor distribution criterion for designing agroforestry practices, American ginseng and sugar maple make suitable companion forest crops. Most forest farming operations with herbal medicinals are likely to be less intensive and labor-demanding than a ginseng and maple combination. It is instructive, however, for illustrating how the demands of such an intensive system might be accommodated if labor requirements are distributed among seasons, and activities undertaken on behalf of one component can benefit, or at least not interfere with, the needs of the other.
There appears to be complementarity between ginseng and maple also with respect to markets and marketing strategies. A large scale maple producer in New York state, for example, has developed a “ginseng-laced” maple syrup product that is sold at farmers’ markets in New York City. This popular product sells out within the first few hours of each weekend market day. Maple producers are likely to be familiar with the informal, word-of-mouth nature of marketing, as well as the historical tendencies to under-report production and sales, sometimes not reporting at all, to avoid income taxes on these micro-scale, family-based enterprises. Thus the informality of the herbal medicinal marketing system is unlikely to be an obstacle to their participation in the industry. In this sense, American ginseng and sugar maple might be considered complementary sectors of the informal rural economy. The challenge for agroforesters is to identify or design other tree-crop combinations with similar complementary characteristics, and to optimize under site specific conditions those that have been identified.
Exploring the Potential of Herbal Medicinals
Important biological factors, in evaluating the potential of particular medicinal herbs for cultivation in forest environments, include the soil characteristics of the plant’s native range and the ease of propagation. Little has been documented concerning the specific soil nutrient requirements of most perennial root herbs, though studies are in progress to improve this information for American ginseng (Buck, 1999) and a foundation has been laid for goldenseal (Davis, 1993). Ginseng, for example, is known to require high levels of calcium and a pH between 5 and 6. Other nutrient requirements, however, are not well known, neither is there a good understanding of how apparently nutrient-limited soils provide calcium and other essential nutrients to the ginseng plant. An hypothesis that decaying maple leaf material that is present in the surface layer of forest soils may be a principal agent in the provision of calcium under conditions in the northeast where ginseng appears to colonize and grow most prolifically is under investigation (unpublished data, 1998, L. Buck). Better understanding is needed of plant-soil relations in perennial root-based forest farming practices in order to provide the understory plants’ nutrient requirements under conditions of continuous cultivation. Such knowledge requirements are opening new frontiers for interdisciplinary research by forest ecologists, horticulturalists and soil scientists.
The propagation requirements of potential herbal root crops will be an important determinant in the feasibility of expanded production by forest owners. Plant propagation operations need to be simple, and success probable, to interest most woodland managers in becoming involved. To illustrate the possibilities for bringing some promising perennial root crops under commercial cultivation in forest environments, we identify general ecological and propagation requirements for five herbal medicinals. This sampling of information is drawn principally from Foster (1993), to whom the reader is referred for more in-depth treatment of the uses, ecology and cultivation of numerous North American medicinal herbs. The potential for woodland cultivation of American ginseng and goldenseal are further explored in the section that follows.
“The root of life”, American ginseng is believed to invigorate, rejuvenate and revitalize the human system, while research suggests a scientific basis for the use of ginseng as an adaptogen or general body tonic. While the plant can be relatively difficult to cultivate, it is a proven commercial crop which grows in eastern North American woodlands and favors north- or east- facing slopes and well-drained, humus-rich, light-textured loam soils. Heavy clay or sandy soils will not promote healthy plants. Blood meal, bonemeal and leaf mold can be used as soil amendments, with light applications of lime or wood ashes to maintain the pH balance. Shade of 70 to 90 percent is required. Propagation is by seed which may take six to twenty months to sprout. The seed should be stratified before planting which involves placing the seed in a coarse medium and maintaining it at a temperature just above freezing for four to six months. Most stratified seed, planted in the autumn, will germinate in the spring and the remainder the following year. Alternatively, one-, two-, or three-year-old roots can be purchased for planting. Buyers risk introducing diseased stock into their ginseng bed by this method, although reputable dealers guard against this. It requires a minimum of 5-7 years before a good root crop is obtained.
The resinous black cohosh root has been used traditionally to treat various menses-related conditions. More recently, studies have confirmed its effectiveness in the treatment of menopause-related symptoms. The plant grows in woodland shade from Southern Ontario to Georgia, west to Arkansas and north to Wisconsin. It is adapted to a wide range of conditions and relatively easy to grow. Black cohosh thrives under lightly shaded conditions. While adaptable to relatively poor, acidic, rocky woodland soils it does best in a rich, moist forest soil. The plant is propagated by sowing seeds in well-prepared seed beds as soon as they are ripe in autumn for germination the following spring, or by division of the roots in early spring or autumn after the leaves begin to fade. A crop is obtained in about 3-4 years.
Bloodroot has been an obscure woodland botanical that has experienced a dramatic increase in marketability in recent years mainly for the production of an antiplaque agent for dental care products. The plant grows in cool, moist, rich, shaded deciduous woods from Southern New York and New Jersey to Northern Florida, West to East Texas and north to Wisconsin and Southern Canada. Attempts to dry or stratify seed for future planting usually result in failure. Therefore, after it is collected in the autumn when the moisture content is comparatively low, the seed must be immediately sown before the aril dries. The plant may be propagated also by planting rhizome cuttings in late summer or early fall, though this method is not always successful. Detailed controlled studies are needed to determine the best methods of propagating bloodroot for the purpose of commercial production. The species needs shade but blossoms in early spring before leaves appear in most deciduous forests, exposing plants to nearly full sun at the beginning of its life cycle. It is adaptable to different soil types - one that is rich in humus with good drainage and not excessively moist is most suitable. It takes 3-4 years to obtain a crop. Studies have shown that plants in the southern part of the range, especially the southern Appalachian mountains, have the highest alkaloid content in the roots. Soil pH and humus are known to be significant factors in alkaloid content.
The root of this plant was used traditionally for gynecological purposes including the assistance of child delivery, and to treat bronchitis, pneumonia and whooping cough. Modern research suggests it may have contraceptive possibilities. Blue cohosh occurs in moist, rich woods from New Brunswick to South Carolina, west to Arkansas and north to North Dakota and Manitoba, being most abundant in the northern part of its range. The plant likes a humus-rich soil in deciduous forests and tolerates a wide pH range between 4.5 and 7. It is not subject to pests and requires a minimum of care. It can be propagated by seed or root division. Plants grown from seed need to be in the ground for up to five years before the roots can be harvested. A good candidate for commercial cultivation, blue cohosh can be grown in a habitat similar to that for ginseng and goldenseal.
Purple Coneflower (Echinacea)
Foster (1993) considers Echinacea the most interesting American medicinal plant from a historical and modern perspective. It has been used to treat dozens of conditions and today is most widely valued in supporting and stimulating the immune system, including treatment for colds and influenza. The genus is represented by nine species and two varieties indigenous to North America with distribution centered in Arkansas, Kansas, Missouri and Oklahoma. Purple coneflower has a fibrous root that grows in open woods. It likes a moderately rich, well-drained soil and is drought resistent. Propagation is by seed or by carefully dividing branching crowns from the main rootstock in spring or fall. Sown from seed, the roots are ready to dig in three to four years. Plants propagated by division can be harvested two years after planting.
This herb is valued as a tonic used to treat numerous internal and external ailments. In its native haunts it grows in similar habitats to ginseng - moist, rich, deep-shaded woods. As a potential cash crop in woodland cultivation conditions, it has several advantages over ginseng. It can be harvested in as little as three years compared with ginseng’s five or more. It is easier to propagate and not subject to the disease and pest problems that can encumber ginseng cultivation. Goldenseal can be propagated by seed, division of rhizomes or by planting the “eyes” from vigorous root fibers. Seed should be stratified before planting. Goldenseal will grow best in a deep, loose, friable soil high in organic matter, especially composted leaf mold. It requires well-drained soils, a pH of around 5.5. to 6.5 and about 75 percent shade.
Woods Cultivation of Ginseng and Goldenseal
Presently, American ginseng and goldenseal are the most valuable herbal, medicinal root crops in the US and Canada. Wild populations of both have been over-exploited and their harvest is regulated by law, more strictly in some states than others. The rapidly expanding market value of these herbs has made the monitoring and enforcement of protective strategies extremely difficult, making native roots increasingly scarce. Efforts to cultivate these plants stem back to the early 1900's. Several historical and modern publications are available containing procedural recommendations for cultivation, based on the experience of relatively knowledgeable growers. The reader considering going into production is referred to these growers guides (Beyfuss, 1994; Scott, 1994; Persons, 1994a). The following discussion focuses on trends and issues in forest farming these two medicinal herbs to illustrate the concept, and to provoke thought about expanding it to encompass other, lesser known forest medicinals.
Ginseng has been known and respected for centuries. It is regarded as a multi-purpose tonic for improving strength and vitality. The active agents, or saponins, in ginseng are known as gincenocides. It is not well known how they work in the body, though they are reputed to improve the mental, physical and spiritual efficiencies of the brain, thereby inducing better sleep, appetite, energy and well-being (Sason & Dailey, 1995). American ginseng was first exported from Canada to China in the 1700's. Its qualities are believed to complement Chinese ginseng (Panax ginseng L.), the former being a stimulant, or heating agent, and the latter a relaxant or cooling agent (Roth, 1996, personal communication). Ginseng cultivation was the subject of considerable activity and scientific investigation around the turn of the century (Van Hook, 1904). In about 1910, however, fungal diseases became an insurmountable obstacle and by World War I the efforts were essentially abandoned. With the advent of better fungicides following World War II, cultivated ginseng became a crop of notable value, most being produced in open fields under artificial shade in capital-intensive, mechanized farming operations. This product is appreciably different from the wild plant to connoisseurs. In texture, taste and presumed potency and effectiveness, artificially cultivated ginseng is considered inferior, its value in the market place reflects these perceptions.
Presently, as domestic and international demand for wild ginseng increases, an over-supply of the artificially cultivated product has sent prices plummeting. Furthermore, disease problems associated with this method have again begun to plague the industry, resulting in considerable uncertainly about its viability during the next few years. Artificially cultivated ginseng is now worth about five to ten percent of the value of wild roots depending on the source and age of the wild plants. Woods-grown ginseng is closer in price to wild than to artificially cultivated ginseng, depending on whether it is grown by wild-simulated, or more intensively cultivated methods. The more closely the cultivated product simulates the wild plant in appearance, texture and taste, the greater its value. In general, the less densely the plant is grown and the fewer chemicals applied, the more closely it resembles the wild root, assuming that basic resource requirements are met in each case.
Ginseng occurs naturally as part of the forest flora under hardwood stands throughout the eastern half of North America, from southern Canada to central Alabama and from the east coast to just west of the Mississippi River. Though comparatively little is known about the ecology of this woodland plant, a study by Anderson et al. (1993) that focused on the central parts of the species range along the Mississippi and Ohio Rivers concluded that ginseng performs best in sugar maple and mixed oak forests generally on north-facing slopes. The authors speculated that these sites were best because they were moist and cool, with relatively high levels of calcium and phosphorus and low levels of potassium. The same sites were seen to have low light and disturbance levels.
Various observers have described conditions under which ginseng appears to grow naturally (Koehler, 1912; Persons, 1994a). A good wild-simulated planting site will have a high shade canopy provided by hardwoods, at least some slope for drainage, rich woods soil with high organic matter content, and either an already existing population of wild ginseng or other forest floor plants like trillium (Trillium spp.), ferns, mayapple and bloodroot which are often found with wild ‘sang’. There seems to be concurrence about its need for 70-90 percent shade, deep well-drained soils - neutral to slightly basic (non-acidic) and rich in micro-nutrients. A heavy mulch of leaves from its native environment provides a steady supply of essential nutrients as well as protective cover.
Seven to ten years are required to bring a plant to maturity under wild-simulated conditions, depending on latitude. In tilled beds under hardwood shade, the time can be reduced to five-to-seven years, presuming that adequate artificial fertilizers are applied. If roots instead of seeds are planted a marketable product is obtained earlier. Two- and three-year-old rootlets can be thinned from seeded beds and sold as rootstock to provide an intermediate crop, or planting stock for the grower’s own additional beds, while a crop of marketable seed can be harvested each year after the third growing season.
For a plant that has such value and that attracts such a great deal of attention, knowledge about its characteristics and performance is surprisingly incomplete. Although ginseng has been cultivated in North America for over 100 years, research on mechanisms controlling growth and development of the plant has been minimal. Better information is needed about environmental variables and their inter-relationship, particularly in relation to photosynthesis and dry matter partitioning. Disease control is the central problem in world ginseng production and requires an integrated approach (Proctor, 1993). And, to protect the interests of consumers, more needs to be known about relations between environmental and cultural variables, and the potency of the roots.
Furthermore, there is no documentation of the amount of ginseng grown in low cost forest gardens, nor of the amount of wild ginseng that is harvested from berries planted by long-time diggers or by their fathers or grandfathers, or by farmers growing ginseng in a wild-simulated manner. Yet these two low-cost traditional methods of producing ginseng in its native woodland habitat are potentially profitable, even on a small scale, and in the US are probably practiced by more people, though on much less acreage, than artificially-shaded cultivation.
A survey was undertaken by a well-known ginseng producer with extensive experience, Scott Persons, author of American Ginseng: Green Gold (1994a), through his network of contacts (Persons, 1994b). Woods growers are understandably secretive about their operations. Therefore knowledgeable people throughout the twenty eastern states that have ginseng certification programs were asked to estimate the nature and extent of woodland cultivation. The survey revealed that woods-growing is widespread but nearly always small scale and there is little standardization of the techniques. A variety of methods is used to cultivate woodland beds and to plant areas for wild-simulated production, and various kinds of difficulties are encountered. It was found that costs, yields and profits vary greatly among farmers who grow ginseng in its native forest environment.
The survey estimated that there were between 800 and 900 “woods-cultivated” growers in the twenty states, caring for about 200 ha (500 acres), and approximately 3,400 “wild-simulated” growers in the same region managing just over 360 ha (900 acres). Together they are farming about 570 ha (1,400 acres), an average of about 0.12 ha (one-third of an acre) per ginseng farmer, demonstrating that woods-growing as practiced in the US throughout ginseng’s wild range is predominantly a small scale enterprise.
Persons estimated that woods-cultivated growers are harvesting an average of 900 kg per ha of dried root (800 pound per acre) after an average of six years of growth. Assuming no failure (with great optimism), he calculates that about 30,000 kg (66,000 pounds) of woods-cultivated root might be produced each year, representing some four percent of the roughly 680,000 kg (1.5 million pounds) of cultivated root being exported each year from the US. Similarly, if wild-simulated growers harvest an average of 179 kg per ha of dried root (160 pounds per acre) after an average of nine years of growth, the maximum weight of wild-simulated root produced each year would be about 7200 kg (16,000 pounds). This represents about eleven percent of the roughly 68,000 kg (150,000 pounds) of wild roots being exported from the US each year.
Finally, exploring the profitability of these production methods, Persons draws on his own experience as well as reports from many growers to estimate costs, yields and profits on a conservative basis, acknowledging that much higher yields and profits are sometimes achieved, but assuming no major setbacks. Similar estimates are reported in his American Ginseng: Green Gold (Persons, 1994a), based on a 0.2 ha (one-half acre) size of operation. We have adjusted these estimates to reflect more recent market prices.
Using the wild-simulated method, growers could expect to produce about 36 kg (80 lbs.) on 0.2 ha (half acre). If sold at $573.00/kg ($260.00/lb), they could expect a net profit of about $15,300. At $661.00/kg ($300.00/lb) annual profits would increase to some $18,500 from 0.2 ha (half an acre). For the woods-cultivated method assuming sales at $441.00/kg ($200.00 per pound), growers could average a gross income of $80,000, and a net profit of about $65,000. Assuming a very conservative price of $220.00/kg ($100/lb), gross income would be about $40,000 and net profits about $25,000. These figures include costs for labor. There is no other legal crop that comes close to this level of profitability. By comparison, net profits for artificially shaded ginseng, recently priced at $44.00/kg ($20 per pound), are about $7,407/ha ($3,000 per acre) and probably lower due to losses from disease. The time to maturity, however, using the cloth shade method is three to four years, compared with five to seven for woods-cultivated, and six to twelve for wild-simulated.
The easier and less expensive wild-simulated method can be undertaken profitably on a large or small scale. One person can reasonably plant 0.4 ha (one acre) or more each year without mechanized equipment, even on steep hillsides; the quality of harvest depending on the suitability of the particular planting site. Preparing cultivated beds under the forest canopy requires considerably more labor, thus there are often constraints on expanding to 0.4 ha (a full acre) size operation using this method.
A few woods-cultivated growers represent exceptions to the small scale approach. These entrepreneurs have converted numerous hectares of forest into a contiguous system of densely planted ginseng beds, rendering normal regeneration of forest plants - including trees - impossible. These growers depend on continuous chemical treatments to control fungal diseases, and to clear new areas for expanding the number of beds. While exceptionally profitable in the short term, the sustainability and efficacy of this type of operation is highly questionable.
The major factor limiting the farming of ginseng in its native forest habitat is poaching. Stealing ginseng plants is common and the losses are large both financially and emotionally, so many growers quit.
Goldenseal, a native herbaceous perennial, is a highly valued medicinal herb which has been collected from the forests of the eastern United States for generations. It is used to treat a wide variety of disorders ranging from sore throats to cancer; its pharmacological properties being attributed to the alkaloids hydrastine and berberine (Davis, 1993). Due to its popularity, native goldenseal populations have been significantly depleted in some areas. Thus, the species is becoming scarce throughout its range from southern New York to Minnesota and western Ontario, south to Georgia and Missouri. The greatest goldenseal-producing states are Ohio, Indiana, Kentucky and West Virginia. In North Carolina it is classified as an endangered species, making collection from the wild illegal. To meet the increasing demand and prevent further depletion of native populations, goldenseal cultivation is being tested and encouraged.
The cultivation of goldenseal is similar to that of ginseng although somewhat easier because goldenseal is less prone to disease than ginseng, and has a shorter life cycle. It is easily propagated by rhizome divisions or rootlet cuttings, or by seed which must be kept moist and stratified before germination the spring following harvest and planting. Seed-grown plants are ready to harvest in four or five years. Plants grown from rootlets or rhizome divisions may be harvested in two to four years, though three is most common.
A 0.4 ha area (one acre) can yield about 1,816 kg (4,000 pounds) of dry roots after three years. At the recent value of $66.00/kg ($30.00/pound), it is possible to generate a gross income of $29,640/ha ($12,000/acre). The cultural conditions under which the plant is grown approximate those of ginseng. It calls for well-drained soil, rich in humus, and partially shaded. It withstands transplanting well. An easy way to propagate is to bring plants in from the forest and transplant them to a prepared location, or to collect the rootstocks and cut them into as many pieces as there are buds, planting the pieces in a deep, loose, well-prepared soil and mulching. New mulch should be added each year to renew the humus. It is common to space goldenseal 30-cm (one foot) apart and 15 cm (six inches) apart in the row, in beds 1.2 to 2.4 m (four to eight feet) wide with walks between (Koehler, 1912), though the recommended spacing practice is quite variable. Similar to ginseng, goldenseal is commonly poached, posing a significant deterrent to potential growers. Understandably, therefore, most growers do not make information about their operations known.
As for any new or small enterprise venture, it is incumbent on producers of ginseng, goldenseal or other medicinal herbs to anticipate their markets before embarking on production. As knowledge in this domain is often far from “perfect”, more than the normal amount of “faith” may be required in judging whether or not to proceed with production. Because of the long lead time and attendant risks involved in bringing perennial root plants to maturity, this type of enterprise is not for everyone. But for those with patience, a high tolerance for risk, and an appreciation for trial and error learning, the personal and financial rewards can be exceptional. As landowners with such qualities gain experience with these non-traditional practices, information will spread and the general knowledge base can be expected to deepen.
Mushrooms and other fungi are commonly harvested from temperate forests as basic dietary components or as gourmet delights. Unmanaged mushrooms are seasonal crops, as are other fruits and nuts. Their mineral composition, vitamin combinations, and complexes of amino acids make a variety of fungi an important part of the human diet. Native favorites include morels (Morchella spp.) and chanterelles (Cantharellus spp.) (Fig. 8-1) which grow on the forest floor in the north, central and eastern states and honey mushrooms (Armillaria spp.), Chicken-of-the-Woods (Laetiporus sulphureus (Fr.) Murr.), matsutake (Tricholoma magnivelare (Peck) Redhead) and others which grow primarily on wood, but which may also be dependent on unique soil organisms found in their native habitats (Stamets, 1993). Exotic or gourmet mushrooms, such as oyster mushrooms (Pleurotus spp.) (Fig. 8-2) and shiitake (Lentinula edodes (Berkeley) Pegler) (Fig. 8-3), are becoming increasingly popular, but require management to grow in North America, as they are non-native and do not propagate naturally in the wild.
Although fungi are often correctly perceived as indicators of rot in trees, they serve a valuable function as one of the two essential players in living systems - the decomposers (the other essential player is the world of green plants, the producers: consumers, the middle group of players, are not essential). Fungi initially break down hard woody tissues for multitudinous bacteria and other microorganisms to complete the process of recycling the tree nutrients back into the larger ecosystem. In a healthy forest ecosystem, the fungi are in balance with the other components of the system and do not threaten the health of the tree component. Native gourmet mushrooms such as the morels and King Stropharia (Stropharia rugoso-annulata (Farlow and Murrill)) (Fig. 8-4) can be propagated in a wooded environment. Both require some cultivation of the desirable mushroom patch. Several morel species have been identified and occur naturally at different times of the year and in different locations from the northeast to the Pacific Northwest. Although their life cycle has been generally determined (Ower et al., 1986), consistent production has only been successful under laboratory conditions, and the companies growing them guard their proprietary secrets carefully. Spawn kits are available for growing morels in compost, but to date have been unreliable, and may not produce fruit until at least a year after "seeding" the site with spawn. King Stropharia are grown in a bed of wood chips on the forest floor, and may begin producing within three to four months of bed establishment. The site preparation processes for these two species are similar. Artificial propagation of chanterelles to the fruiting stage continues to elude the best efforts of mycologists at this time.
Many of our temperate forests would benefit from TSI, given the cycles of poor management most of them have experienced in the past two centuries. Forest landowners, especially those who own small hectarages (< 10), often do not perform these techniques because the small roundwood (trees < 25 cm dbh) removed in a thinning or TSI operation frequently is unmarketable and thus constitutes a net cost. Utilizing that roundwood for the production of gourmet mushrooms addresses the issue of cost effectiveness of the process.
The public is increasingly interested in a variety of exotic gourmet mushrooms, mostly native to Japan. In addition to shiitake mushrooms, oyster, maitake (Grifula frondosa (Dicks:Fr.)S.F. Gray), reishi (Ganoderma lucidum (Wm. Curtis:Fries) Karsten) (Fig. 8-5), and lion's mane (Hericium erinaceus (Fr.) Pers.) mushrooms depend on the digestion of wood fiber. These mushrooms can all be produced in a similar manner. Fresh cut hardwood logs from living trees are cut into manageable bolts 1m long (3 to 4 feet) and inoculation sites are drilled through the bark into the wood to get the "spawn" of the particular mushroom into direct contact with the carbohydrate-rich sapwood.
Oyster, Lion's mane, and maitake may require partial burial of the prepared logs following inoculation, and in some cases spawn of these species can be inoculated directly into freshly cut stumps of harvested live trees. Oyster mushrooms may also be cultivated on straw or sawdust substrate, but the point of forest farming is to use the forest, both for the log products and for the laying yard for incubation of the inoculated logs.