Key to the

Front 

Editors

1. Boletus spp. 2. Lactarius spp. 3. Inocybe spp. 4. Tricholoma magnivelare camouflaged by maple leaf. 5. Sparassis crispa. 6. Hypholoma spp. 7. Strobilurus trullisatus.

DAVID PILZ is a botanist and RANDY MOLINA is a research botanist and mycology 

team leader, Forestry Sciences Laboratory, 3200 Jefferson Way, Corvallis, OR 

97331.
Managing Forest Ecosystems to

Conserve Fungus Diversity and

Sustain Wild Mushroom Harvests

David Pilz and Randy Molina, Editors

Ecosystem Management of Forest Fungi:

Inventory, Monitoring, and Biodiversity 

Assessment

LaSells Stewart Center, Oregon State 

University,

Corvallis, Oregon

May 3-4, 1994

U. S. Department of Agriculture

Forest Service

Pacific Northwest Research Station

Portland, Oregon

General Technical Report PNW-GTR-371

May 1996
Abstract Pilz, D.; Molina, R., eds. 1996. Managing forest ecosystems to conserve fungus

diversity and sustain wild mushroom harvests. Gen. Tech. Rep. PNW-GTR-371.

Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest

Research Station. 104 p.

Ecosystem management is the dominant paradigm for managing the forests of the

Pacific Northwest. It integrates biological, ecological, geophysical, and silvicultural

information to develop adaptive management practices that conserve biological diversity and maintain ecosystem functioning while meeting human needs for the sustainable production of forest products. Fungi are important components of forest ecosystem management because they perform essential ecological functions, many species

are associated with late-successional forests, and commercial harvest of wild edible

mushrooms contributes significantly to the regional economy.

Inventory and monitoring provide essential information for improving management

decisions, but fungi present a unique set of sampling challenges. To address these

unique challenges, a conference entitled "Ecosystem Management of Forest Fungi"

was convened May 3-4, 1994, in Corvallis, Oregon. This publication describes the

forest management context of fungus inventory and monitoring issues, summarizes the

mycological studies presented at the conference, and provides a synopsis of audience

discussion. A common understanding of the challenges encountered when studying

forest fungi will facilitate the planning and accomplishment of inventory and monitoring

activities by improving communication among concerned individuals, interest groups,

and land managers.

Keywords: Fungi, mushrooms, ecosystem management, forest management, inventory, monitoring, biodiversity, special forest products, mycorrhizae.




Introduction

The Pacific Northwest (a geographical region encompassing southeast Alaska, British Columbia, 

Washington, Oregon, Idaho, western Montana, and northern California) has long been recognized 

for its rich mycota (fungus biota), particularly the macrofungi that produce large, showy, fleshy 

sporocarps (fruiting bodies of mushrooms, truffles, conks, puffballs, and cup fungi). Much of that 

richness is directly related to the region's expansive forest communities, diverse weather patterns, 

and numerous tree species. Forest tree species form beneficial root symbioses (called mycorrhizae) 

with specialized fungi, and this factor contributes significantly to the diversity of fungi in the Pacific 

Northwest. Indeed, many of the mushrooms seen on the forest floor during late summer and autumn 

are the reproductive structures of mycorrhizal fungi that obtain their carbohydrate nutrition via the 

roots of host trees. The wood of live and dead trees and the abundance of other organic debris on 

the forest floor provide rich resources for numerous saprobic (decomposer) and parasitic fungi. 

Fungi also feature prominently in the complex forest food web, providing sustenance for organisms 

from microbes to mammals. These four major roles of fungi-mutualisms (especially mycorrhizal), 

nutrient cycling, pathogenesis, and food web resource–are cornerstones in the dynamic functioning 

of forest ecosystems, contributing to overall resiliency and diversity. If we are to succeed at 

managing forest ecosystems in their entirety, we must integrate the biological and functional 

diversity of forest fungi into future management plans.

Over the last decade, the extensive commercial harvest of several species of edible, forest 

mushrooms has heightened awareness and concern for forest fungi by both the public and resource 

managers. Schlosser and Blatner (1995) estimate that wild mushroom harvests contributed 

approximately $40 million to the economies of Oregon, Washington, and Idaho in 1992. Along with 

the economic benefits, however, came conflicts between recreational and commercial mushroom 

harvesters, and concerns about the potential overharvest of wild mushrooms and the impact of 

mushroom harvesting on forest ecosystems. Public outcry in the region led to enactment of

1
2

legislation to regulate the commercial harvest of wild mushrooms on public lands in 

Washington (Washington State House Bill 2865, 1992) followed shortly by similar legislation in 

Oregon (Oregon State House Bill 2865, 1993). Since then, the U.S. Department of Agriculture 

(USDA), Forest Service, and U.S. Department of the Interior (USDI), Bureau of Land 

Management, have implemented permit systems for commercial and recreational harvest of 

wild forest mushrooms as one of several "special forest products." Users of the resource 

claimed that the regulations were arbitrary and based on little factual data regarding 

sustainability of the wild mushroom harvest.

A lack of knowledge regarding the biology and ecology of these unique forest organisms 

contributed to this controversy. The nature of the commercial industry was likewise a mystery. 

Users and managers disagreed on how best to manage and regulate the mushroom resource 

given the lack of harvest impact data. To bring interested parties together for sharing 

information, the Forest Service and Oregon State University sponsored a regional workshop in 

Springfield, Oregon, in November 1991 titled "Biology and management of wild, edible 

mushrooms in Pacific Northwest ecosystems"; over 300 attended. The objectives were to 

educate managers on the biology and ecology of forest fungi (particularly the commercially 

harvested species), discuss the social and economic issues of the commercial harvest, provide 

a forum for sharing concerns, and develop an information network for future mycological 

collaboration. Molina and others (1993) synthesized the findings of that workshop and set the 

groundwork for long-term regional management and monitoring of commercially harvested 

fungi.

The enactment of President Clinton's forest plan for the Pacific Northwestern United States, as 

detailed in the Forest Ecosystem Management Assessment Team (FEMAT) report (1993), 

provided new urgency for integrating forest fungi into the new ecosystem management 

paradigm. Five hundred and twenty-seven fungus species were identified as rare or 

old-growth-forest dependent and, therefore, potentially in need of protection under the regional 

plan. The viability of these species was evaluated as part of nine management alternatives. The 

final record of decision (USDA and USDI 1994) listed 234 fungus species as requiring 

immediate attention under the four survey -and-manage strategies of the plan. Among the eight 

groups of organisms listed (fungi, lichens, bryophytes, amphibians, mammals, mollusks, 

vascular plants, and arthropods), fungi was the largest. Two fungus species received the 

highest protected status; surveys for these organisms must be conducted before any new 

ground disturbance. Surveys and management of known sites for listed organisms must begin 

in 1995, and long-range plans call for regionwide mycological surveys over the next 10 years. 

The record of decision also emphasizes the need to manage and monitor special forest product 

species, such as edible mushrooms, within the emerging regional plan.

The FEMAT guidelines mandate an unprecedented study of fungi in the forests of the Pacific 

Northwest. Although FEMAT specifically addresses forests within the range of the northern 

spotted owl (Strix occidentalis caurina ) in the United States, the surveys it mandates have 

added impetus to fungus studies throughout the geographical region. Professional mycologists 

and forest managers are concerned about the availability of knowledge and skilled individuals 

to conduct the fungus surveys and develop monitor-
ing programs. We organized the workshop, "Ecosystem Management of Forest Fungi," to begin 

meeting these urgent training needs. Our primary objectives were to:

 • Review the fundamental ecological roles of fungi in forest ecosystems

• Discuss concepts of biological diversity and conservation for forest fungi

• Discuss the ecology, productivity, and sustainability of commercially harvested 

forest fungi

• Discuss challenges and specific procedures for assessing fungus diversity and productivity

• Provide an update on current, relevant mycological research in the Pacific Northwest

• Provide opportunities to coordinate regional FEMAT-related surveys and monitoring activities

• Develop an ecosystem management and long-term monitoring framework for forest fungi

The workshop focused on mycorrhizal and some saprobic fungi because these groups encompass 

the valuable commercial species and those listed in the record of decision. Pathogens received only 

limited discussion and microfungi, none.

This publication documents the main presentations of the workshop and summarizes many of the 

issues. The first two sections address diversity and conservation of forest fungi and productivity and 

sustainable harvest of commercially valuable wild mushrooms, including the historical context of 

these issues and the unique challenges and considerations researchers face. Current studies 

presented at the conference are used to illustrate approaches to meeting these challenges, and are 

referenced in the discussions. Several authors have expanded their original presentations, added 

comments, answered questions brought forward by participants, and incorporated new data.

Finally, the principles of ecosystem management are illustrated with examples of managing forest 

fungi and a discussion of practical approaches for integrating forest fungi into ecosystem 

management. We view this workshop publication and its recommendations as essential first steps in 

the adaptive management process (Bormann and others 1994), whereby newly acquired information 

is continuously incorporated into revised management plans. Many of the survey and monitoring 

protocols are in their early years of field testing, and management recommendations are based on 

the best available information. As new monitoring information and field techniques become available, 

they should likewise be evaluated within the adaptive process. Managers can thus build on and use 

an ever-increasing store of shared experience and knowledge in their efforts to monitor and manage 

this critical resource.

3
Literature Cited Bormann, B.T.; Cunningham, R G.; Brookes, M. H. [and others]. 1994. Adaptive

ecosystem management in the Pacific Northwest. Gen. Tech. Rep. PNW-GTR-341.

Portland, OR; U.S. Department of Agriculture, Forest Service, Pacific Northwest

Research Station. 22 p.

Forest Ecosystem Management Assessment Team. 1993. Forest ecosystem management: an ecological, economic, and social assessment. Portland, OR; U.S.

Department of Agriculture; U.S. Department of the Interior [and others]. [Irregular

pagination].

Molina, R.; O'Dell, T.; Luoma, D. [and others]. 1993. Biology, ecology, and social

aspects of wild edible mushrooms in the forests of the Pacific Northwest: a preface

to managing the commercial harvest. Gen. Tech. Rep. PNW-GTR-309. Portland, OR;

U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station.

42 p.

Oregon State House Bill 2865. 1993. Chapter 167, Laws and Resolutions of 1993,

67th Oregon Legislative Assembly, Effective June 24, 1993.

Schlosser, W.E.; Blatner, K.A.1995. The wild edible mushroom industry of Washington, Oregon and Idaho: a 1992 survey. Journal of Forestry. 93(3): 31-36.

U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior,

Bureau of Land Management. 1994. Record of decision for amendments to Forest

Service and Bureau of Land Management planning documents within the range of

the northern spotted owl. [Place of publication unknown]. 74 p.

Washington State House Bill 2865.1992. Chapter 184, Laws of 1992, 52nd Washington Legislative Assembly, Effective June 11, 1992.

Biological 

Diversity
1Thomas E. O'Dell is with the Botany Department, University of Washington, 

Seattle, WA 98195; Jane E. Smith and Michael Castellano are with the USDA 

Forest Service, Pacific Northwest Research Station, Forestry Sciences 

Laboratory, 3200 Jefferson Way, Corvallis, OR 97331; and Daniel L. Luoma is 

with the Department of Forest Science, Oregon State University, Corvallis, OR 

97331.

Diversity and Conservation of 

Forest Fungi

Thomas E. O'Dell, Jane E. Smith,

Michael Castellano, and Daniel Luoma1

Biological diversity has several meanings; most commonly it means the number of 

species in a particular location or habitat (species richness). It may also include the 

genetic diversity within species. This topic has immense practical importance to the 

sustainability and quality of human life and to human impacts on the environment.

Although human beings depend on other organisms for our survival, we have no 

accurate inventory of all species for any location. Our knowledge is directly proportional to the conspicuousness of a group of organisms; we know more about large 

vertebrates than about invertebrates and more about forest trees than forest fungi. 

Paradoxically, the "charismatic megafauna," about which we have the greatest understanding, depend (as do humans) on the poorly understood and inconspicuous groups 

such as fungi and bacteria. We know the least about the diversity of those organisms 

most fundamentally important to our existence.

The microbial world challenges our ability to describe diversity. A thimbleful of soil may 

contain 5 billion bacterial cells, perhaps 500,000 (about 0.1 percent) of those cells will 

grow in culture and have a chance of being identified to species. Perhaps 1 percent of 

the many thousands of types of fungi in that soil grow in culture. Because estimates of 

microbial diversity depend on growing cultures to identify species, our knowledge of soil 

microbial diversity lacks detail.
Soil fertility depends on bacteria for nitrogen fixation and fungi to release nutrients from 

organic matter, maintain soil structure, and aid plant nutrient and water uptake. These 

vital processes sustain agricultural and forest productivity; hence the effect of land 

management practices on soil microbial communities directly impacts resources needed 

by humans.

Genetic diversity within species, populations and individuals is arguably the most 

valuable natural resource available to humanity. The development of new crop varieties 

and plants with disease resistance uses germ plasm from wild relatives of the crop 

plants. Similarly, the multibillion dollar global pharmaceutical industry uses natural 

products, or chemicals derived from them, for many medicines (Farnsworth and Soejarto 

1985, Groombridge 1992). An especially salient example for foresters in the Pacific 

Northwest is the anticancer drug "taxol," recently derived from the Pacific yew tree 

(Taxus brevifolia Nutt.) (Campbell 1991). Yet around the world, this biological inheritance 

is being diminished. The demand for natural resources is degrading terrestrial and 

aquatic ecosystems while depleting biological diversity at an alarming rate. Rates of 

species extinction currently approach the "mass extinctions" of the fossil record. In some 

groups of plants, it is estimated that up to one-half of the species may become extinct 

during the next 50 years (Smith and others 1993).

Many people believe that all organisms (including fungi) have an inherent right to exist. 

This premise is expressed by religions teaching that humans should act as responsible 

stewards of the land (Berry 1982) and that organisms have intrinsic value (Cobb 1988). 

This sense of responsibility for nature led to legislative protection of outstanding or 

scenic ecosystems (National Parks and Wilderness Areas) and prominent species (the 

Endangered Species Act, U.S. Laws 1973). There is growing recognition, however, that 

all species are valuable in the web of life and that the only practical means of conserving 

diversity is through appropriate management of representative habitats.

Why care about fungi, forest fungi in particular? Why are they important? What do we 

know about their diversity in natural ecosystems? How can we broaden our understanding? What steps are necessary for protecting their diversity?

We cannot include all fungi in this discussion; they simply are too numerous. We will 

focus on mushrooms, truffles, puffballs, and shelf and cup fungi, a group that produces 

large sporocarps and encompasses many important ectomycorrhizal, saprobic, and 

parasitic species. The many other types of fungi critically important to the function of 

healthy ecosystems include molds, yeasts, lichen symbionts, endophytes, and 

endomycorrhizae. These fungi are more difficult to study, however, especially in natural 

settings, and their sheer numbers can overwhelm scientists and managers alike. In 

contrast, scientists have a century of observations about the rarity or commonness of 

large sporocarp production in natural settings, and some of the current concern about 

fungi in forest ecosystems is engendered by the large-scale harvest of a few commercially valuable species.

Some ectomycorrhizal fungi form long-lived symbioses with the roots of higher plants 

(for reviews see Allen 1991, Harley and Smith 1983, O'Dell and others 1993). The fungi 

can extend the nutrient-absorbing surface area of the roots, produce extracellular 

enzymes that increase phosphorous and nitrogen availability, increase host drought

Fungus Diversity
tolerance, and protect against pathogens (Trappe and Fogel 1977). In return, the fungi 

receive host photosynthate as their main source of carbon. Some sources estimate 50 to 70 

percent of the net annual productivity of trees may be translocated to roots and associated 

mycorrhizal fungi (Fogel and Hunt 1979, Norton and others 1990, Vogt and others 1982). 

Exudates and hyphae of ectomycorrhizal fungi form a major link between aboveground 

producers and soil food webs, providing an energy source for a wide range of bacteria, 

protozoa, arthropods, and microfungi. Many large edible mushrooms, such as chanterelles 

(Cantharellus species) and matsutake (Tricholoma species) are sporocarps of mycorrhizal 

fungi.

Saprobic fungi perform essential ecosystem functions by decomposing organic matter and 

cycling nutrients. Some species, such as the Armillaria mellea complex, may originally infect 

trees as parasites and then continue to decompose trees after death. Many saprobic 

macrofungi can decompose cellulose, chitin, and lignin, essential abilities for decaying wood 

(Moorhead and Reynolds 1992). By decomposing coarse woody debris, these fungi soften the 

interiors of snags and logs, which allows birds and small mammals to burrow into them and 

create nests and dens (Harmon and others 1986; Maser and others 1978, 1988; Perry 1994; 

Thomas and others 1979). Well-rotted coarse woody debris also retains large quantities of 

water during dry weather, and this reserve is tapped by mycorrhizal fungi and tree roots that 

grow through it. Several saprobic species produce edible sporocarps commonly collected by 

humans, including oyster mushrooms (Pleurotus ostreatus), angel wings (Pleurotus 

porrigens), lion's mane (Hericium abietis), and sulfur-shelf (Laetiporus sulphureus) (Arora 

1986).

Pathogenic fungi contribute to habitat diversity in forests by killing trees that later become 

snags and logs inhabited by wildlife and a variety of other organisms. Gaps in the canopy 

develop when diseased trees die and fall, and shade-intolerant plants flourish in these 

openings (Holah and others 1993). Thus, pathogenic fungi increase plant species diversity 

and create wildlife habitat. Some fungal parasites of tree roots produce mushrooms that 

humans eat, such as the honey mushroom (Armillaria mellea complex) (Arora 1986).

Mushrooms and truffles are important wildlife food (Carey 1991, Fogel and Trappe 1978, 

Maser and others 1978). They are consumed by deer, elk, bear, small mammals, and 

mollusks. Some rodents, such as the California red-backed vole (Clethrionomys califomicus) 

and northern flying squirrel (Glaucomys sabrinus), rely on these sporocarps for over 90 

percent of their food supply (Hayes and others 1986, Maser and others 1985) and are, in 

turn, primary prey for species such as the northern spotted owl. Insects also consume 

sporocarps and are affected by sporocarp diversity and abundance (Fogel and Peck 1975, 

Worthen and McGuire 1990).

The commercial harvest of forest fungi in the Pacific Northwest has become a multimillion 

dollar industry. Recreational pickers also take to the woods to seek tasty morsels for the 

dinner table. Details of the wild mushroom harvest can be found in Molina and others (1993) 

and Schlosser and Blatner (1995) and will be discussed later in this publication.

Fungi remain an untapped reservoir of potential medicines. Many contain promising 

immune-stimulating and anticancer substances and have long been esteemed in Asian

7
pharmacopoeias. Western medicine is beginning to examine fungi for treatment of 

AIDS, other viral diseases, and some cancers (Jong and Donovick 1989).

Given these many reasons to value and conserve fungus diversity, concern is growing 

over its possible loss. European studies provide salient documentation for this concern; 

decreased or discontinued fruiting has been noted among many species of macrofungi, 

coincident with widespread forest decline (Gulden and others 1992) and loss of forest 

habitat. In several long-term studies, diversity of ectomycorrhizal species has diminished 

by half since the 1950s (Arnolds 1991). Fungus species associated with late 

successional forests show the greatest decline.

In the Pacific Northwest, habitat alteration, principally due to logging, and the potential 

impacts from commercial harvest of mushrooms are the primary concerns. Exclusion 

of fire from habitats where it is a normal disturbance also may have impacted fungus 

species. Logging and other management activities affect fungi differently (some 

species increase, others decrease), and impacts on particular species or fungus 

diversity as a whole require further investigation (study 2, this document; North 1993; 

O'Dell and others 1992).

Much of the controversy surrounding the management and harvest of late successional 

forests in the Pacific Northwest during the last decade has centered around the northern 

spotted owl and its listing as a threatened species under the Endangered Species Act 

(U.S. Laws 1973). Legal challenges to forest management plans emphasized that many 

other species also depend on this declining habitat. Managing portions of the forest for 

each individual species that may be threatened is not generally practical and habitat 

needs overlap considerably. Preserving biological diversity requires holistic 

management of forest ecosystems, including the physical processes and biological 

interactions that sustain viable populations of numerous species over time.

Following President Clinton's April 2, 1993, forest conference in Portland, Oregon, the 

Forest Ecosystem Management Assessment Team (FEMAT; 1993) developed management alternatives (within the context of environmental laws) to balance forest conservation with the economic and social needs of people in the Pacific Northwest. The team 

focused on the maintenance and restoration of biological diversity, particularly in late 

successional and old-growth forests within the geographic range of the northern spotted 

owl. FEMAT evaluated the likelihood of maintaining sufficient well-distributed habitat on 

Federal lands to provide for continued viability of 1,119 fungus, plant, and animal 

species associated with old-growth forests. The panel of mycological experts identified 

527 fungus species (47 percent of all species listed) as strongly associated with 

old-growth forests or their legacy (for example, coarse woody debris).

The Final Supplemental Environmental Impact Statement (FSEIS; USDA and USDI 

1994a) shows additional analysis on late successional- and old-growth-related species. 

It focuses on public comments to the preferred alternative (alternative 9) and addresses 

the following objectives: (1) identify species needing additional consideration and 

analysis, (2) gather pertinent information on potential impacts of forest management on 

these species, and (3) discuss specific mitigation measures, including their benefits and 

costs of implementation.

Conservation of Fungi 

and the President's 

Northwest Forest Plan
Of the 1,119 species initially considered, 715 had adequate habitat protection or were not 

expected to be adversely affected by the cumulative effects of anticipated land management 

activities, so were dropped from further consideration. Of the 214 fungus species that 

remained on the list after this screening, 129 are known from only one or a few sites. Eighty 

of these are endemic to the Pacific Northwest. The FSEIS specifies site management for all 

type localities to ensure continued viability of each species. Additional research on the 

population biology of these species will facilitate efficient management of these sites.

The final record of decision (USDA and USDI 1994b) is the document that specifies how the 

FSEIS will be implemented. Table C-3 in that document lists 234 fungus species deemed "of 

special concern." These species were analyzed and classified into four survey categories. 

Survey strategy 1 requires management of known sites for all species shown in table C-3. 

Sites with rare and endemic fungus species will have 64.8 hectares (160 acres) temporarily 

withdrawn from management activities until those sites can be thoroughly surveyed and 

site-specific management measures prescribed. One particular fungus, the "noble polypore" 

(Oxyporus nobilissimus), will have 240 hectares (600 acres) of habitat preserved at each 

known fruiting location. Survey strategy 2 requires surveys before the occurrence of any 

ground-disturbing activities. Only two fungus species require this strategy: Oxyporus 

nobilissimu and Bondarzewia Montana [note: B. Montana (Quel.) Sing. will be changed to 

B. mesenterica (Schaeff.) Kreisel in the near future]. Survey strategy 3 requires conducting 

extensive surveys to find high-priority sites for species management. All 234 fungus species 

are included in survey strategy 3, and protocols are currently under development. The 

general regional surveys of strategy 4 are designed to provide further information about 

little-known species not yet designated as rare and endemic. These regional surveys must 

begin before 1997 and are expected to take 10 years to complete.

The FSEIS survey strategies apply to all Federal lands in the range of the northern spotted 

owl, and Federal research agencies are developing the monitoring protocols. The Pacific 

Northwest Research Station represents the U.S. Department of Agriculture, Forest Service, 

in this program. Research activities of land management agencies within the U.S. 

Department of the Interior (National Parks, Bureau of Land Management, and Fish and 

Wildlife Service) were recently merged into the National Biological Service and given the 

mission "to gather, analyze, and disseminate the information necessary for the wise 

stewardship of our Nation's resources ...." Immediate priorities include establishing or 

expanding research and inventory programs in biologically diverse areas or in unique 

ecosystems, and documenting which species live in the United States, where they live, and 

how they are related to one another in an evolutionary sense. A report of the National 

Research Council (1993) recommends inclusion of macrofungi; however, funding is 

generally not yet available to survey and monitor them.

The FEMAT report, the FSEIS, and the final record of decision have set the initial course 

for conservation of forest fungi in Pacific Northwest forests by stipulating management of 

known sites and initiating long-term, regionwide surveys on the distribution and 

abundance of listed fungi. Researchers and managers must collaborate to develop 

practical field procedures and information protocols for monitoring and protecting wild 

fungi.

9
Investigators who study fungus diversity and the ecosystem functions of macrofungi must 

consider a unique set of research challenges and practical considerations when designing 

and implementing their survey, monitoring, and research activities.

The thallus (literally "body") of a fungus typically consists of a web of hyphae (filaments or 

threads of cells) collectively called "mycelium." This mycelium grows immersed in its 

substrate (wood, host tissue) or habitat (soil) and thus is concealed from casual observation. 

An individual fungal thallus (also "mycelium" or "mycelial colony") may live for many years in 

one spot yet produce sporocarps infrequently. We currently depend on the occurrence of 

these ephemeral and sometimes sporadically produced sporocarps to demonstrate the 

presence of a species at a site, with the exception of perennial woody conks. Therefore, a 

site must be repeatedly scrutinized to survey or monitor species of interest. Failure of a 

species to fruit for several years evokes uncertainty about whether the colony has died, lies 

dormant, or is merely not fruiting.

Although some species, (for example, Coprinus comatus) can fruit whenever environmental 

conditions are appropriate, most species fruit in a particular season. Within that season, a 

particular set of environmental conditions generally is necessary to trigger fruiting. For 

example, chanterelles and russulas can start fruiting in early to mid summer given sufficient 

moisture, but other species, such as matsutake, rarely fruit until temperatures cool in the 

autumn, even if moisture is available earlier. Mushrooms that fruit in a particular season may 

still fruit at different times of the year in different locations. For instance, matsutake fruits in 

August in northern British Columbia, September and October in the Oregon Cascade 

Range, and November in the Siskiyou Mountains. Even in nearly the same location, different 

habitats can influence fruiting phenology. In the Oregon Dunes National Recreation Area, 

matsutake can start fruiting in August in the fog zone within a few kilometers of the coast, or 

as late as November slightly further inland.2 Ammirati and others (1994) illustrate the strong 

phenological component of field mycological studies. They visited a site weekly from April 

through December for 2 years. Species differed in the months in which they were 

encountered, and from year to year, given species were observed in different months. About 

half of the autumn species were observed in either September or October but not in both 

months. About a third of the autumn species would have been missed by sampling in a 

single month, more if fewer samples were taken per month.

Fungi produce sporocarps in response to environmental and physiological factors, 

especially adequate moisture and appropriate temperatures, and general descriptions of 

seasonal fruiting patterns are available for many species. Spring fruiting usually occurs with 

the onset of warm days and nights. Plant species that depend on warm temperature rather 

than increasing day length for flowering, such as Linnaea borealis (twin-flower), are useful 

indicators of spring fruiting. Such indicator species are particularly useful for less easily 

observed hypogeous (underground-fruiting) species that form truffles. After dry summers, 

autumn fruiting typically begins 10 to 14 days after the first rain that is sufficiently heavy to 

wet the top few centimeters of soil beneath a forest canopy. Fruiting diminishes with 

snowfall or heavy frosts. The specific local combination of moisture and temperature that 

initiates fruiting, however, has been described for wild species in only a few cases (Hosford 

and Ohara 1995, Norvell and others 1995).

Research Challenges 

and Considerations

Detection of Species

Phenology

2Personal communication. 1994. Dan Seggotta, botanist, Oregon 

Dunes National Recreation Area, Siuslaw National Forest, Reedsport, 

OR 97467.
Timing of seasonal fruitings and response to weather conditions also are influenced by 

site-specific factors. For instance, forests at high elevations experience more dew and 

fog drip than those at low elevation, thereby allowing fungi to fruit at high elevations 

during otherwise dry summer months. Likewise, forest stands with relatively open 

canopies may allow brief rain showers to penetrate and wet the forest floor more 

readily than stands with dense canopies. Other than these general observations, few 

data exist on the fruiting responses of fungi to site-specific conditions.

Long-term phenological studies that correlate site and weather factors with patterns of 

fruiting are needed to allow researchers and managers to reliably predict sporocarp

production. It is even possible that multiple-year patterns in the physiology of host 

trees (similar to 5- to 7- year cycles in conifer cone-production levels) may influence 

annual fruiting of mycorrhizal fungi.

Given the large variation in fruiting phenology among species and our current inability 

to predict annual fruiting patterns, repeated sampling is required to fully characterize 

fungus diversity in forests. Sampling in both spring and autumn is necessary to capture 

the dichotomy in seasonal fruiting patterns among many species. Thorough species 

inventories require at least 5 years of monthly to weekly visits during potential fruiting 

seasons. Selecting study sites that will not experience timber harvesting, mushroom 

picking, or other disturbances during this initial period provides baseline data uncomplicated by such extraneous influences. Regular sampling visits are costly, so conveniently located sites are important. Sampling objectives may be modified to capture 

diversity only at the peak fruiting season, but this limitation should be clearly noted in 

reported results.

The most important consideration in planning any study is a clear objective. If the 

objective is to locate a specific rare fungus, then a "walk-through" by a trained mycologist may be most efficient. If a landowner merely wants a list of species occurrences, 

then a foray by a mycology club could be useful. Quantitative surveys of species 

frequency and abundance require systematic sampling methods, and if goals include 

the comparison of multiple sites or response to treatments (for example, timber or 

mushroom harvesting) then careful experimental design is essential.

Field sampling designs originally developed to inventory vegetation do not take into 

account the unique characteristics of fungi (Villeneuve and others 1989, Winterhoff 

1992), particularly the patchy distribution of sporocarps. If the study encompasses 

multiple sites being visited weekly (equal areas should be examined with equal frequency at each site), several field crews may be needed or the sampling area at each 

site reduced. Sample area and sampling frequency deemed adequate to characterize 

diversity on a given site, or among compared sites, must be balanced with available 

personnel and fiscal resources through careful study design.

Fungi that occur on a particular, discrete substrate (for example, dung, leaf, log, or 

twig) can be sampled by treating the natural unit (leaf, cone, and so forth) as a 

sampling unit. Dividing a site into selected microhabitats and scrutinizing a subsample 

of each is referred to as "stratified" sampling, an efficient sampling design for 

substrate-specific groups of fungi.

Sampling Frequency

Sampling Design
Mushrooms, especially ectomycorrhizal species, often fruit in clusters or patches. 

Sampling designs with plots immediately adjacent to each other are likely to underestimate species diversity (O'Dell and others 1995), but widely spaced plots are more time 

consuming and costly to sample. Plot size and shape also influence sampling efficiency and practicality. Studies comparing the usefulness of various sampling designs 

for meeting different study objectives are needed to expedite fungus surveys, monitoring, and research.

Study objectives also determine which sampling methods may be used. Documenting 

the presence of a rare species may be as simple as photographing, collecting voucher 

specimens, and ascertaining the fruiting location. Species lists, systematic surveys, 

long-term monitoring, and assessments of ecological niche or functioning require 

progressively more elaborate sampling methods.

Indices that combine numbers of species present (richness) with the abundance of 

each species are commonly used when the ecological implications of species diversity 

are studied. Three measures of sporocarp abundance are commonly employed: 

counts, frequency (percentage of plots in which the species is present or absent), and 

biomass. The choice of how fungi are measured directly affects which species is 

considered most important. To illustrate: consider measuring a plot containing one 

boulder weighing 10 kilograms (22 lbs), three cobbles totaling 5 kilograms (11 lbs), and 

10 pebbles totaling 1 kilogram (2 lbs). All are equally frequent (one plot), pebbles are 

most numerous, and boulders have the most mass. Bear in mind that "abundance" 

(however defined) of sporocarps is an unknown reflection of the size and extent of the 

thallus of a given species. Sporocarp biomass may partially reflect annual changes in 

the energy reserves of a given fungus, but large genetic differences likely exist among 

species in the relative percentage of resources allocated to sporocarp production. 

Frequency reflects the area colonized by a species and therefore is a useful indicator of 

distribution. Numbers of sporocarps reflect neither resource allocation nor extent of 

mycelium but, like biomass, reflect annual variation in productivity within a species. A 

combination of measures may be most descriptive. Studies should explain why 

particular measures of abundance were selected.

Different sampling methods are needed for different types of fungi; for example, sporocarps of hypogeous (belowground) fungi, such as truffles, are generally produced 

below the soil surface. Their detection requires excavation and this causes sufficient 

habitat disruption that subsequent fruiting in the same location does not represent 

undisturbed conditions; typically, therefore, new plot locations are selected each 

sampling period. Epigeous (aboveground) sporocarps, such as mushrooms, are more 

easily located, but researchers must decide whether to simply count them, count 

number of plots where they are present, pick and weigh them (with potential impacts on 

subsequent fruiting), or count and measure their size. Study objectives and practical 

concerns dictate whether permanent or new plot locations are used.

Studies of ectomycorrhizal species diversity also can sample ectomycorrhizal root tips 

directly–a procedure described in study 3. Counting ectomycorrhizal root tips in soil 

cores estimates the extent to which various ectomycorrhizal fungi are colonizing root 

tips in a natural setting, thereby providing a more direct measure of mycelial abunSampling Methods 

and Units of Measure
dance and ecological function than sporocarp production. To date, most studies of field 

ectomycorrhizae have relied on visually characterizing morphological types. The advent of 

quick, easy, and inexpensive molecular techniques for genetic identification will allow these 

types to be verified and identified to species. This advance will, in turn, allow researchers to 

correlate sporocarp abundance with mycorrhiza abundance (Gardes and Bruns 1991, 1992, 

1993; Gardes and others 1991).

Sample processing methods depend on both the material collected and the planned 

analyses. Identification is essential to diversity assessment; hence, specimens that cannot 

be recognized immediately must be handled appropriately for subsequent examination. The 

identification of some species is facilitated by promptly noting fresh characteristics that 

quickly fade. Some mushrooms and most truffles can be refrigerated for several days, but 

other species decay overnight. Familiarity with identification keys and sporocarp 

characteristics is essential for knowing how to handle each specimen. Where identification 

cannot be conducted promptly, the typical procedure is to note fresh characteristics and dry 

the specimens for later examination. Some molecular techniques of genetic analysis can 

use dried material, but other procedures require fresh or frozen material. For measures of 

abundance that use biomass, collected mushrooms and truffles may be weighed fresh but 

commonly are dried to obtain comparable biomass data, because water content of 

sporocarps differs widely. Ectomycorrhizal root tips in soil cores can be refrigerated for 

weeks and separated for microscopic examination as needed.

Collecting mushrooms and truffles is a relatively easy (albeit methodical) process, but 

identification often is challenging. Many mushrooms are easily identified, but many others 

can be reliably identified only by experts who prefer to examine fresh rather than dried 

specimens. Because most refrigerated collections remain fresh for only a few days, drying is 

necessary if timely examination by a taxonomist is not possible. Field personnel must be 

familiar with important features used in fungus keys so that they can take adequate notes on 

fresh characteristics for subsequent identification of dried samples.

Identification guides have only limited usefulness for some groups of North American fungi. 

For example Cortinarius, the most diverse mushroom genus, received its most thorough 

North American treatment over 50 years ago (Kauffman 1932). Consequently, collected 

species are often of unknown taxonomic affinity; that is, possibly described (but not in easily 

accessible literature), undescribed (that is, new to science), or not previously reported from 

North America. Distinctive species often can be readily identified by using popular field 

guides, but because of taxonomic difficulties, identifications of many species are frequently 

unreliable. Any investigation of fungi should document identifications with voucher 

collections deposited in an herbarium (Ammirati 1979).

Studies of fungus diversity are hampered by a shortage of trained mycological taxonomists, 

especially individuals with broad experience. Suggestions for resolving this difficulty are 

discussed in the last section of this publication.

Conserving species diversity and sustaining the functional roles of fungi in forest 

ecosystems requires maintenance of diverse habitats for the growth and reproduction of 

numerous species. Although habitat requirements overlap among many species, others 

need specific or unique habitats to survive. We typically know little about these

Taxonomy

Habitats and 

Forest 

Management
requirements; our ignorance often results from the difficulties of studying fungi and limited 

resources to do so.

The principles of conservation biology also are based on maintaining genetic diversity within 

species. This is accomplished by preserving numerous populations and ensuring gene flow 

among them. Ignorance of the population and reproductive biology of most fungi currently 

hinders conservation efforts. We poorly understand, for example, how long colonies live, how 

often new colonies are established, or how far apart they can be and still mate. These data are 

necessary to determine the size and distribution of appropriate forest habitats necessary for 

conserving fungus diversity.

Studies to fill the gaps in our knowledge may be either taxon or habitat based. Taxonbased 

studies target particular species. For example, Oxyporus nobilissimus and Bondarzewia 

montana are uncommon fungi requiring taxon-based inventory of habitats throughout their 

range. Study 5 in this document describes inventory and conservation measures for rare taxa.

A habitat-based approach correlates species distribution with environmental factors. Study 1 

examines fungus diversity in several old-growth forest communities differing in annual rainfall. 

Species composition of ectomycorrhizal fungus communities also changes as forests mature; 

some species are more prevalent in young, others in older stands (Arnolds 1991, Deacon and 

Fleming 1992, Hinitikka 1988, Termorshuizen and Schaffers 1987). Study 4 examines relative 

fungus diversity in stands of varied age. Comparisons of mycological data from disturbed 

(harvested or burned) and undisturbed (old-growth) forests are needed to understand fungus 

community dynamics. Correlating site habitat factors such as coarse woody debris, stand age 

and density, understory vegetation, and soil conditions with fungus sporocarp occurrence will 

increase our knowledge of the effects of forest management practices on fungus diversity. 

Study 3 is an integrated research project addressing these issues.

Experiments with forest management treatments (for example, forest thinning or leaving 

coarse woody debris in areas that are clearcut) are useful for examining the response of fungi 

to management practices. These projects use many of the sampling methods discussed in this 

section, but sampling is conducted within the context of larger integrated research programs 

studying many ecosystem components. Studies 2, 3, and 6 are examples of this approach.

Taxonomic and sampling difficulties need not discourage us from learning more about 

distributions of macrofungi. Much empirical data exist for Europe (Arnolds 1992), and many 

investigations are underway in the Pacific Northwest. Cooperation among research institutions 

and land management agencies ensures that taxonomic, experimental design, statistical, and 

publication expertise is combined with practical field experience, and that results will be 

incorporated into updated management plans. Members of mycological groups, as well as 

graduate students in botany, forestry, and other natural resources, often provide invaluable 

field assistance; studies discussed in the next section have relied heavily on their support and 

will continue to benefit from their efforts.

Fungi perform indispensable ecosystem functions and have the potential to provide a broad 

range of sustainably produced commercial products. If diligently pursued, knowledge, 

conservation, and use of the diverse fungi in our region will reward society .

Cooperation

14
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18

Conference Presentations on Diversity and 

Conservation of Forest Fungi

Study l: Ecology of Ectomycorrhizal Fungi in Old

Growth Pseudotsuga menziesii-Tsuga heterophylla

Forests of Olympic National Park

Thomas E. O'Dell and Joseph F. Ammirati1 2

Despite their importance in many ecosystem processes, the ecology of ectomycorrhizal 

fungi in unmanaged habitats is little studied in North America (Klironomos and Kendrick 

1993). A few investigators have documented fungus species distributions in hardwood 

versus coniferous forests in eastern North America (Bills and others 1986, Nantel and 

Neuman 1992, Villeneuve and others 1989). In northwestern North America, such 

studies (except for that of Cooke 1955) have focused on hypogeous (truffle-like) fungi 

(Fogel and Hunt 1979, Hunt and Trappe 1987, Luoma and others 1991). Hypogeous 

fungi, while ecologically important, comprise a small fraction of ectomycorrhizal species.

Although Pseudotsuga menziesii is estimated to host over 2,000 species of 

ectomycorrhizal fungi, little is known of the variation in fungus species richness 

between stands or habitats where it occurs (Molina and others 1993, Trappe 1977). 

Old-growth P. menziesii-Tsuga heterophylla (Douglas-fir–western hemlock) forests 

were selected for this study because the correlation between understory vegetation and 

climate is well documented (Franklin and Dyrness 1973, Henderson and others 1989, 

Zobel and others 1976), and the forest types are regionally important.

Context

1Authors are with the Botany Department, University of Washington, Seattle, WA 98195.

2Cooperating was E.G. Schreiner, Olympic National Park, National Biological Service, U.S. Department of 

the Interior. Funds were provided in part by the National Science Foundation, DEB-9203262.

19
20

The Olympic National Park, with large areas of native forests and steep environmental 

gradients, is ideal for studying ectomycorrhizal fungi in relation to environment. The Olympic 

Mountains, rising steeply from the surrounding coastal plain and foothills, create a barrier to 

moisture-laden air from the Pacific Ocean. This geography creates a steep precipitation 

gradient with average annual rainfall of up to 600 centimeters (236 in.) in west-side valleys, 

compared to less than 50 centimeters (20 in.) in the rain shadow to the east. The western 

hemlock zone is the most common forest zone on the peninsula (see Houston and Schreiner 

1994, for thorough discussion of climate, vegetation, and geology of the Olympic Peninsula).

1. Describe occurrence of mycorrhizal fungus species in a range of old-growth P. 

menziesii–T. heterophylla forest types.

2. Determine whether mycorrhizal fungus species show preference for different plant 

associations.

3. Estimate standing crop of mycorrhizal fungus sporocarps in these associations.

4. Determine environmental factors that correlate with species diversity and sporocarp 

production.

5. Describe the spatial patterns of sporocarp production.

Communities of ectomycorrhizal fungi, mushrooms, and their allies, were examined in the P. 

menziesii–T. heterophylla zone, in autumn 1992 and 1993 and spring 1993 and 1994. Within 

this zone, three understory vegetation types were studied and two to three stands from each 

type were sampled. A stand sample consisted of two parallel 245-meter-long (268-yd-long) 

transects, 5 meters (16 ft.) apart, each with one hundred, 4-square-meter (43-ft.2) circular plots 

at 5-meter (16-ft.) intervals for a total area of 400 square meters (480 yd2). Sporocarps were 

collected and vegetation data recorded for each plot. Sporocarps were identified, dried, and 

weighed to determine biomass. Species observed in the stand, but not in plots, were collected 

for species richness estimates, but were not included in biomass calculations. Percentage of 

cover by all perennial plant species and large woody debris was estimated in each plot. The 

diameter at breast height of all woody stems over 1 centimeter (0.39 in.), height of canopy 

dominant trees, and increment cores to obtain age and growth data for all size classes of trees 

were measured in two 500- or 1000-square-meter (600-1200-yd2) plots (the minimum size 

necessary to include at least 30 stems) in each stand.

Plant communities for sampling were selected from field reconnaissance for common 

understory vegetation types. Multiple stands of each type were sampled to determine whether 

species of fungi prefer particular plant communities. Only putative ectomycorrhizal species, 

those producing above-ground sporocarps, were sampled, because of resource limitations; 

adding truffles or other groups of fungi would have restricted the study to fewer sites. Multiple 

samples were taken each season to increase the chance of detecting species that fruit for 

short times. The use of small sampling plots dispersed along transects was chosen on the 

assumption that a greater proportion of species in a stand would be detected than by using 

large plots divided into continuous subsamples. This sampling design also allowed testing for 

spatial

Objectives

Methods and 

Rationale
21

Unique

Considerations

Current Status

Literature Cited

patterns of sporocarp production. Plots were used to standardize the area sampled so that the 

different sites could be compared. Transects were moved for each sample period to avoid 

disturbance effects due to removing sporocarps. Plant associations were classified according to 

Henderson and others (1989.)

About 70 percent of species observed were actually collected in plots using this design. A few 

plots had extremely large biomass (over 10 grams [0.35 oz.] dry weight), while most had little or 

no biomass (that is, no sporocarps were present). Because of the large number of plots with no 

biomass, spatial pattern analyses are unreliable.

1. Funding limitations restricted research to 2 years, with one person working full-time on the 

project. No funds were available to hire additional field assistants.

2. A special challenge was identifying the great diversity of fungi encountered, particularly in 

the genus Cortinarius.

2. Lead investigator Thomas O'Dell had the opportunity to improve his mushroom 

3. identification skills from collaboration with coinvestigator and expert mushroom 

taxonomist, Joseph Ammirati.

4. Access to Olympic National Park, where substantial old-growth forests are protected 

and extreme environmental gradients occur, was a unique opportunity.

Suggestions for future improvements in similar studies include:

1. Increased duration. The difference between the two years was extreme; a longer study 

would provide better comparisons among habitats, stands, and species.

2. Increased sampling frequency and area. Several species were observed in the stands 

but outside the sampled area, thus indicating the need to sample a larger area, or do 

more intensive sampling (more plots in the same total area). Ideally, one should 

sample weekly to fortnightly to detect most species.

3. Improved replication of habitats. Old-growth vegetation is highly variable. Conducting 

fungus studies of stands where the vegetation is already mapped would facilitate 

finding stands with similar vegetation, hence minimizing within-habitat variation. More 

stands of each type also could be sampled to compensate for existing within-habitat 

variation.

Data analysis, problem identifications, and manuscript preparation are continuing. 

Sampling will continue at two sites for an additional project comparing sporocarp 

abundance and ectomycorrhizal dominance.

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ecosystem: distribution patterns and turnover. Canadian Journal of Forest Research. 9: 

245-256.
22

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edible mushrooms in the forests of the Pacific Northwest: a preface to managing commercial 

harvest. Gen. Tech. Rep. PNW-GTR-309. Portland, OR; U.S. Department of Agriculture, Forest 

Service, Pacific Northwest Research Station. 42 p.

Nantel, P.; Neuman, P. 1992. Ecology of ectomycorrhizal basidiomycete communities on a local 

vegetation gradient. Ecology. 73: 99-117.

Trappe, J.M. 1977. Selection of fungi for ectomycorrhizal inoculation in nurseries. Annual 

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Villeneuve, N.; Grandtner, M.M.; Fortin, J.A. 1989. Frequency and diversity of ectomycorrhizal 

and saprophytic macro-fungi in the Laurentide Mountains of Quebec. Canadian Journal of 

Botany. 67: 2616-2629.

Zobel, D.B.; McKee, A.; Hawk G.M.; Dyrne ss, C.T. 1976. Relationship of environment to 

composition, structure and diversity of forest communities of the central western Cascades of 

Oregon. Ecological Monographs. 46:135-156.
23

Objectives

Context

Study 2: Response of Ectomycorrhizal Fungi to Forest

Management Treatments: Implications for Long-Term

Ecosystem Productivity

Daniel L. Luoma, , Joyce L. Eberhart, and Michael P. 

Amaranthus1 2

Much of the interest in maintaining site productivity relates to a desire for nondeclining flows of 

timber harvest. On public lands, timber production is being integrated, however, into ecosystem 

management regimes where all the values we derive from forests are being managed 

interactively. Ectomycorrhizal fungi are important strands in the web of life in the soil and are 

essential for nourishing trees (Trappe and Fogel 1977).

This study examines critical aspects of the ecology of ectomycorrhizal fungi and will have 

strong management implications. The integrated research and extended perspective offered 

by this study will, for the first time, produce information on long-term interactions among 

mycorrhizal fungi, sustainable ecosystem productivity, and forest management practices.

This study was initially targeted for the Siskiyou Integrated Research Site in southwestern 

Oregon. Insight gained about the relations between disturbance effects, ectomycorrhizae, and 

site productivity will enable important interregional comparisons with the work of Harvey and 

others (1976, 1991) in the northern Rocky Mountains. Intraregional comparisons of sporocarp 

production will be possible with Fogel (1976), Hunt and Trappe (1987), Luoma (1991), Luoma 

and others (1991), and O'Dell and others (1992).

This study is part of a large integrated research experiment on long-term ecosystem 

productivity (LTEP). It is designed to examine how vegetation structure in three classes (early, 

mid, and late seral stage) and coarse woody debris (CWD) at three relative levels of retention 

(low, medium, and high) interact to influence various ecosystem processes. Three important 

objectives of this study are to compare among early and late seral vegetation stage and low 

and high coarse woody debris treatments as follows:

1. The richness and relative abundance of ectomycorrhizal types as extracted from soil cores.

2. The species richness and biomass of ectomycorrhizal fungus sporocarp production.

3. The correlation between ectomycorrhizal type richness and sporocarp production.

1Daniel Luoma and Joyce Eberhart are with the Department of Forest Science, Oregon State University, Corvallis, OR 97331; and 

Michael Amaranthus is with the U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Grants Pass, 

OR 97526.

2Cooperating was Robyn Darbyshire, Siskiyou Integrated Research Site, Chetco Ranger Disuic, Siskiyou National Forest, Brookings, 

OR 97415.
The study is not intended to inventory or estimate total ectomycorrhizal species or type 

richness. Rather, the objectives are tailored to the framework of the experimental design. 

We are interested in characterizing species richness and biomass from representative 

samples in a manner that allows for testing of treatment effects.

This study benefits from the opportunity to obtain pretreatment data. Although this is the 

ideal situation, such data cannot always be obtained. Pretreatment data were gathered in 

stands that will receive high and low CWD treatments within each early and late 

successional treatment. This is a 2- by 2-split-plot design. Including the untreated control 

stand, this design yielded five sample stands per block of the LTEP study design. Based 

on experience from studies in progress, previous work (Luoma 1991), and anticipated 

technical support, available resources were deemed adequate to sample three blocks for 

a total of 15 sample stands. Sampling the midsuccessional treatment was considered 

less critical because sporocarp production studies are underway in even-aged managed 

stands at the H.J. Andrews Experimental Forest (study 4).

Intensive sampling was conducted to provide high-quality data with useful levels of 

statistical precision. At least 2 years (preferably 3 years) of pretreatment sampling are 

necessary (Arnolds 1981, Fogel 1981, Lange, 1948, Luoma 1991, Richardson 1970) to 

establish reliable baseline data. These data quantify pre-existing variation within and 

among experimental units, thus clarifying interpretation of treatment effects and 

strengthening resultant inferences.

Each stand was sampled once each spring and autumn from spring 1992 through spring

1994. Ectomycorrhizal fungus community structure, as reflected by sporocarp production, 

has a strong seasonal aspect in our region (Fogel 1976, Hunt and Trappe 1987, Luoma 

and others 1991). Presumably, this seasonal response reflects aspects of 

ectomycorrhizal dynamics. Sporocarp sampling is timed to coincide with peak seasonal 

fruiting. Root sampling also centered on the fruiting season but may be extended over a 

longer part of the season. Post-treatment sampling (in 3-year increments) should occur 

during years 0-2, 4-6, 9-11, 14-16, 19-21, 29-31, and 49-51 and every 20 years 

thereafter. Luoma (1989), O'Dell and others (1992), and our studies in progress show 

differences in ectomycorrhizal fungus community structure by comparing stands at ages 

of 25 and 50 years and between 80, 160, and 400+ years. Little is known of mycorrhizal 

dynamics during the first 20 years after disturbance.

Ectomycorrhizal mushroom species were sampled by using 2- by 50-meter (6.56- by 

164-ft.) strip plots. Treatment units were stratified into upper, middle, and lower slope 

positions. Three strip plots were permanently installed in each treatment stand sampled, 

one in each slope position. Three transient mushroom strip plots also were surveyed in 

each sample period, one in each slope position. At each sample period, hypogeous 

sporocarp production (truffles) was assessed in 25 systematically placed 4-square-meter 

(43 ft.2)plots. The truffle plots were established in conjunction with the transient 

mushroom plots along three transects with eight, nine, and eight plots each. Truffle plots 

were placed every 6 meters (19.7 ft.) along the center line of the transient mushroom 

plot. The transient mushroom plots were sampled only once with three new plots 

established each sample period.

Methods and 

Rationale

24
Ectomycorrhizae were sampled by use of 6- by 15-centimeter (2.3- by 5.9-in.) soil cores. Cores 

were taken at each end of each permanent mushroom strip plot and a subset of transient plots. 

Three to six cores per treatment unit were obt ained in each of three sample periods. Each core 

was washed in an elutriator and screened with 2-millimeter and 250-micrometer sieves. The 

coarse fraction was spread evenly in a 25.4-square-centimeter (4.06 in.2) tray divided into 36 

compartments with a plastic insert. Within each compartment, each ectomycorrhizal type 

encountered was recorded. This procedure provided the determination of relative frequency for 

each ectomycorrhizal type within the core. The mean number of types and relative frequency of 

each type will be used for treatment comparisons. The correlation between ectomycorrhiza 

abundance and sporocarp biomass will be tested.

Results from this study demonstrated utility of pretreatment sampling (Eberhart and others, in 

press; Luoma and others, in press). Because observed post-treatment differences could have 

origins in pretreatment conditions, baseline data enable analysis of post-treatment data with a 

broader range of tests than otherwise would be possible. These tests provide increased 

confidence and inferential power during interpretion of results. Sampling both sporocarps and 

ectomycorrhizae enables researchers to make complementary treatment comparisons and will 

provide insights into the relations between ectomycorrhiza abundance and sporocarp 

production.

Pretreatment data collection is finished. Harvest treatments will be implemented in 1996.

Arnolds, E. 1981. Ecology and coenology of macro-fungi in grasslands and moist 

heathlands in Drenthe, The Netherlands. Vaduz, Liechtenstein: J. Cramer. 410 p.

Eberhart, J.L.; Luoma, D.L.; Amaranthus M.P. [In press]. Response of ectomycorrhizal 

fungi to forest management treatments–a new method for quantify ing morphotypes. In: 

Proceedings, 4th European symposium on mycorrhizae; 1994 July 11-14; Granada, Spain. 

[Place of publication unknown]: [Publisher unknown].

Fogel, R. 1976. Ecological studies of hypogeous fungi. II: Sporocarp phenology in a 

western Oregon Douglas-fir stand. Canadian Journal of Botany. 54: 1152-1162.

Fogel, R. 1981. Quantification of sporocarps produced by hypogeous fungi. In: Wicklow, D.T.; 

Carroll, G.C., eds. The fungal community, its organization and role in the ecosystem. New 

York: Marcel Dekker: 553-568.

Harvey, A.E.; Larsen, M.J.; Jurgensen, M.F. 1976. Distribution of ectomycorrhizae in a 

mature Douglas -fir/larch forest soil in western Montana. Forest Science. 22: 393-398.

Harvey, A.E.; Page-Dumroese, D.S.; Graham, R.T.; Jurgensen, M.F. 1991.

Ectomycorrhizal activity and conifer growth interactions in western-montane forest soils. 

In: Proceedings, Management and productivity of western-montane forest soils; [dates of 

meeting unknown]; [location of meeting unknown]. Gen. Tech. Rep. INT-280. [Place of 

publication unknown]; U.S. Department of Agriculture, Forest Service: 110-118.

Hunt, G.A.; Trappe, J.M. 1987. Seasonal hypogeous sporocarp production in a 

western Oregon Douglas-fir stand. Canadian Journal of Botany. 65: 438-445.

25

Unique

Considerations

Current Status

Literature Cited
Lange, M. 1948. The agarics of Maglemose. Dansk Botanisk Arkiv. 13: 1-141.

Luoma, D.L. 1989. Biomass and community structure of sporocarps formed by hypogeous 

ectomycorrhizal fungi within selected forest habitats of the H.J. Andrews Experimental 

Forest, Oregon. Corvallis, OR; Oregon State University. 173 p. Ph.D. thesis.

Luoma, D.L. 1991. Annual changes in seasonal production of hypogeous sporocarps in Oregon 

Douglas-fir forests. In: Ruggiero, L.F.; Aubry, K.B.; Carey, A.B.; Huff, M.H., tech. coords. 

Wildlife habitat relationships in old-growth Douglas -fir forests. Gen. Tech. Rep. 

PNW-GTR-285. Portland, OR;: U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Research Station: 83-89.

Luoma, D.L.; Eberhart, J.L.; Amaranthus M.P. [In press]. Response of ectomycorrhizal 

fungi to forest management treatments–sporocarp production. In: Proceedings, 4th 

European symposium on mycorrhizae; 1994 July 11-14; Granada, Spain. [Place of 

publication unknown]: [Publisher unknown].

Luoma, D.L.; Frenkel, R.E.; Trappe, J.M. 1991. Fruiting of hypogeous fungi in Oregon 

Douglas-fir forests: seasonal and habitat variation. Mycologia. 83: 335-353.

O'Dell, T.E.; Luoma, D.L.; Molina, R.J. 1992. Ectomycorrhizal fungal communities in young, 

managed and old-growth Douglas-fir stands. Northwest Environmental Journal. 8: 166-168.

Richardson, M.J. 1970. Studies of Russula emetica and other agarics in a Scots pine 

plantation. Transactions of the British Mycological Society. 55: 217-229.

Trappe, J.M.; Fogel, R.D. 1977. Ecosystematic functions of mycorrhizae. In: Proceedings of the 

below-ground ecosystem: a synthesis of plant-associated processes; [dates of meeting 

unknown]; [location of meeting unknown]. Range Sciences Department Science Series 25. 

Boulder, CO: Colorado State University: 205-214.

26
Study 3: Community Structure and Dynamics of

Ectomycorrhizal Fungi in Managed Forest Stands:

Demonstration of Ecosystem Management Options (DEMO) Program

Daniel L. Luoma, Joyce L. Eberhart, and Michael P.

Amaranth us 1 2

The demonstration of ecosystem management options (DEMO) program will gather data to test 

assumptions in standards and guidelines that currently direct forest ecosystem management in 

the Pacific Northwest. Treatments that implement various levels of live tree retention will be 

examined. The demonstration design consists of six approaches representing diverse retention 

strategies ranging from predominantly evenaged to uneven-aged systems. These experimental 

treatments are described in detail by Ford and others (1995) and White and Esterholdt (1995). 

Research on ectomycorrhizal fungi is an important part of the study.

Studies from the Pacific Northwest indicate that forest management activities can reduce 

abundance of ectomycorrhizal fungi and forest regeneration (Amaranthus and Perry 1989, 

Amaranthus and others 1990). In these studies, the abundance and rapidity of ectomycorrhiza 

formation were critical to seedling survival and growth, especially on harsh sites; however, 

across the Pacific Northwest the degrees of reduction of ectomycorrhizal fungi and impact on 

forest regeneration differ widely and depend on many factors. Ectomycorrhizal fungus species 

differ in their ability to provide particular benefits to their host, and their presence and 

abundance change during forest succession (Mason and others 1983, Trappe 1977). Recent 

research (Amaranthus and others 1994) indicates that previously clearcut young stands 

produce fewer sporocarps than intact mature forest fragments. No information is available, 

however, over a range of partial forest harvests and silvicultural systems.

Vegetational and structural changes during succession in Douglas -fir forests are well known 

(Franklin and others 1981, Spies and others 1988), yet we know little of ectomycorrhizal fungus 

community structure and diversity (Luoma and others 1991). Such data are essential to predict 

impacts of disturbance and management on ecosystem productivity. This study will integrate 

vegetation, wildlife, watershed, and economic responses with knowledge of ectomycorrhizal 

fungi and their underground functions. Critical aspects of ectomycorrhiza ecology that have 

strong management implications will be emphasized.

1Daniel Luoma and Joyce Eberhart are with the Department of Forest Science, Oregon State University,

Corvallis, OR 97331; and Michael Amaranthus is with the U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station, Grants Pass, OR 97526

Cooperators were Rick Abbott, Umpqua National Forest; and Fred Henchell and Ed Tompkins, Gifford Pinchot National Forest.

27

Context
The objectives of this study were:

1. To compare among no harvest and 75 percent, 40 percent, and 15 percent basal area 

retention treatments:

A. The species richness and biomass of ectomycorrhiza sporocarp production. 

(Sporocarp richness and biomass will be correlated with small mammal frequency 

and abundance, and with changes in plant community composition and structure, 

including coarse woody debris.)

B. The richness and relative abundance of ectomycorrhizal types. (Ectomycorrhizal 

richness and relative abundance will be correlated with changes in plant community composition and structure.

C. The correlation between ectomycorrhizal type richness and sporocarp species 

richness.

D. The importance of mycophagy in the diet of small mammals.

2. To compare within the 40- and 15-percent green tree retention treatments, the effect of dispersed 

and aggregated retention patterns on:

A. Species richness and biomass of ectomycorrhizal sporocarp production. (Sporocarp 

richness and biomass will be correlated with small mammal frequency and abundance 

and changes in plant community composition and structure.)

B. Richness and relative abundance of ectomycorrhizal types. (Ectomycorrhizal 

richness and relative abundance will be correlated with changes in plant community 

composition and structure.)

The study is not intended to inventory or estimate total ectomycorrhizal species or type richness. The 

objectives are tailored to the framework of the experimental design. We are interested in 

characterizing species richness and biomass from representative samples in a manner that will allow 

for testing of treatment effects.

The integrated DEMO project is designed to replicate six live -tree retention treatments in eight 

geographic locations (blocks). These treatments consist of four levels of live-tree retention (15-, 40-, 

75-, and 100-percent of existing live -tree basal area), with two patterns of retention (aggregated and 

dispersed) applied to the 15- and 40-percent retention treatments). The aggregated pattern consists 

of residual trees retained in clumps of about 1 hectare (2.47 acres) and the dispersed pattern has 

residual trees homogeneously dispersed throughout the unit. For the 75-percent retention treatment, 

all of the cut will occur in about 1-hectare (2.47-acre) patches dispersed throughout the unit. The 

100-percent retention represents the control. Based on experience from studies in progress, previous 

work (Luoma 1989, 1991; Luoma and others 1991; O'Dell and others 1992), and anticipated technical 

support, sampling will be limited initially to three of the replicated blocks.

This study benefits from the opportunity to obtain pretreatment data. Although this is the ideal 

situation, such data cannot always be obtained. At least two years (preferably three years) of 

pretreatment sampling are necessary (Arnolds 1981, Fogel 1981, Lange 1948, Luoma 1991, 

Richardson 1970, Vogt and others 1992) to establish reliable baseline data. These data quantify 

pre-existing variation within and among the experimental units, thus clarifying interpretation of 

treatment effects and strengthening resultant inferences.

28

Methods and 

Rationale

Objectives
Ectomycorrhizal fungus community structure, as reflected by sporocarp production has a 

strong seasonal aspect in our region (Fogel 1976, Hunt and Trappe 1987, Luoma and others 

1991). Each stand will be sampled once each spring and autumn. Sporocarp sampling will be 

timed to coincide with seasonal peak fruiting. Root sampling also will center on the fruiting 

season but may be extended over a longer part of the season. Mycorrhizal typing will generally 

follow the methodology of Eberhart and others (in press). Posttreatment sampling (in 3-year 

increments) should occur during years 0-2, 4-6, 9-11, 14-16, 19-21, 29-31, 49-51, and every 

20 years thereafter.

Ectomycorrhizal mushroom species will be sampled by use of six strip plots (2 by 50 meters 

[6.5 by 164 ft.]) per treatment unit. Long, narrow, strip plots reduce trampling impacts within 

the plots and intercept a wider variety of microsites than circular plots of the same area 

(Luoma and others, in press; Mehus 1986; Ohenoja and Metsänheimo 1982; Ruhling and 

others 1984). During the pretreatment sampling phase, three strip plots will be permanently 

located within the treatment grid. Strip plot placement will be stratified by upper, middle, and 

lower slope position. In stands with gentle slopes, plots will be systematically placed in a 

dispersed pattern.

Sporocarps of each ectomycorrhizal fungus species will be collected separately for each 

square meter of the permanent strip plots. Three temporary mushroom strip plots will be 

established anew with each sampling. Sporocarps of each ectomycorrhizal species from the 

temporary strip plots will be treated as a single collection for that plot. In the laboratory, 

sporocarps will be identified, dried, and weighed to the nearest 0.01 gram to determine 

biomass. Following tree harvest in the dispersed and aggregated retention treatment areas, 

additional strip plots will be systematically assigned within undisturbed patches of residual 

forest. Post-treatment plot location and sampling will be closely coordinated with vegetation 

sampling to broaden the scope of interpretive inference.

Hypogeous sporocarp production will be sampled by using twenty-five 4-square-meter (43-ft.2) 

plots placed every 6 meters (19.7 ft.) along the temporary mushroom plots in the upper, 

middle, and lower slope strata. For truffle fungi, a species collection is defined as a group of 

sporocarps of the same species that form a cluster with a radius < 10 centimeters (3.9 in.). In 

the laboratory, sporocarps will be further identified, dried, and weighed to the nearest 0.01 

gram to determine biomass. In each plot, exposed mineral soil, cover of coarse woody debris 

(CWD), and decay class of the CWD will be recorded to enable analyses for correlation with 

truffle production (Amaranthus and others 1994). Distance from plot center to, and decay class 

of, the nearest piece of CWD > 8 centimeters (3.1 in.) in diameter and = 250 cubic centimeters 

(21.3 in.3) in volume will be compared with distance from each species collection center to the 

nearest coarse woody debris with the same minimum size criteria. The percentage of cover of 

Piloderma bicolor (including related species) also will be recorded in truffle plots because it is 

most readily detected in its vegetative (mycorrhizal) state. Piloderma sp. are frequently found 

in soil with well-decayed woody material, but fruiting structures are rarely found; hence, 

excavation is the most efficient means to quantify relative abundance.

29
As part of a large integrated research project, experimental design and sampling methods must 

conform to the research and management needs of the entire project. The resulting benefit is that 

a wide variety of associated information will be available from other concurrent investigations. Data 

will be entered into the Forest Science Data Bank for permanent storage and use in long-term 

research. Representative voucher collections with the original field labels will be deposited in the 

Oregon State University Herbarium for long-term reference.

Pretreatment baseline data collection is continuing.

Amaranthus, M.P.; Perry, D.A. 1989. Interaction effects of vegetation type and Pacific madrone 

soil inocula on survival, growth, and mycorrhiza formation of Douglas-fir. Canadian Journal of 

Forest Research. 19: 550-556.

Amaranthus, M.; Trappe, J.M.; Bednar, L.; Arthur, D. 1994. Hypogeous fungal production in 

mature Douglas -fir forest fragments and surrounding plantations and its relation to coarse woody 

debris and animal mycophagy. Canadian Journal of Forest Research. 24: 2157-2165.

Amaranthus, M.P.; Trappe, J.M.; Molina, R.J. 1990. Long-term forest productivity and the living 

soil. In: Perry, D.A.; Meurisse, R.; Thomas, B. [and others], eds. Maintaining the long-term 

productivity of Pacific Northwest forest ecosystems. Portland, OR: Timber Press: 36-52.

Arnolds, E. 1981. Ecology and coenology of macro-fungi in grasslands and moist heathlands 

in Drenthe, The Netherlands. Vaduz, Liechtenstein: J. Cramer. 410 p.

Eberhart, J.L.; Luoma, D.L.; Amaranthus M.P. [In press]. Response of ectomycorrhizal fungi to 

forest management treatments–a new method for quantify ing morphotypes. In: Proceedings, 

4th European symposium on mycorrhizae; 1994 July 11-14; Granada, Spain. [Place of 

publication unknown]: [Publisher unknown].

Fogel, R. 1976. Ecological studies of hypogeous fungi. II: Sporocarp phenology in a western 

Oregon Douglas -fir stand. Canadian Journal of Botany. 54: 1152-1162.

Fogel, R. 1981. Quantification of sporocarps produced by hypogeous fungi. In, 

Wicklow, D.T ; Carroll, G.C., eds. The fungal community, its organization and role in the 

ecosystem. New York; Marcel Dekker: 553-568.

Ford, E.D; Aubry, K.B.; White, J.D. [and others]. 1995. Demonstration of ecosystem 

management options: revised draft study plan. 28 p. On file with: U.S. Department of 

Agriculture, Forest Service, Pacific Northwest Research Station, 3625 93d Ave., Olympia, WA 

98512-9193.

Unique

Considerations

30

Current Status 

SsssStatuws

References
31

Luoma, D.L. 1989. Biomass and community structure of sporocarps formed by hypogeous 

ectomycorrhizal fungi within selected forest habitats of the H.J. Andrews Experimental Forest, 

Oregon. Corvallis; Oregon State University. 173 p. Ph.D. thesis.

Luoma, D.L. 1991. Annual changes in seasonal production of hypogeous sporocarps in Oregon 

Douglas-fir forests. In: Ruggiero, L.F.; Aubry, K.B.; Carey, A.B.; Huff, M.H., tech. coords. Wildlife 

habitat relationships in old-growth Douglas-fir forests. Gen. Tech. Rep. PNW-GTR-285. Portland, 

OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 83-89.

Luoma, D.L.; Eberhart, J.L.; Amaranthus M.P. [In press]. Response of ectomycorrhizal fungi to 

forest management treatments–sporocarp production. In: Proceedings, 4th European symposium 

on mycorrhizae; 1994 July 11-14; Granada, Spain. [Place of publication unknown]: [Publisher 

unknown].

Luoma, D.L.; Frenkel, R.E.; Trappe, J.M. 1991. Fruiting of hypogeous fungi in Oregon Douglas-fir 

forests: seasonal and habitat variation. Mycologia. 83: 335-353.

Mason, P.A.; Wilson, J.; Last, F.T.; Walkem, C. 1983. The concept of succession in relation to the 

spread of sheathing mycorrhizal fungi on inoculated tree seedlings growing in unsterile soils. 

Plant & Soil. 71: 247-256.

Mehus, H. 1986. Fruit body production of macro-fungi in some north Norwegian forest types. 

Norwegian Journal of Botany. 6: 679-701.

O'Dell, T.E.; Luoma, D.L.; Molina, R.J. 1992. Ectomycorrhizal fungal communities in young, 

managed and old growth Douglas-fir stands. Northwest Environmental Journal. 8: 166-168.

Ohenoja, E.; Metsänheimo, K. 1982. Phenology and fruiting body production of macro-fungi in 

subarctic Finnish Lapland. In: Laursen, G.A.; Ammirati J.F., eds. Arctic and alpine mycology. 

Seattle: University of Washington Press: 371-389.

Richardson, M.J. 1970. Studies of Russula emetica and other agarics in a Scots pine plantation. 

Transactions of the British Mycological Society. 55: 217-229.

Ruhling, A.; Bååth, E.; Söderström, B. 1984. Fungi in metal-contaminated soils. Ambio. 13: 

34-36.

Spies, T.; Franklin, J.F.; Thomas, T. 1988. Coarse woody debris in Douglas-fir forests of western 

Oregon and Washington. Ecology. 69:1689-1702.

Trappe, J.M. 1977. Selection of fungi for ectomycorrhizal inoculation in nurseries. Annual 

Review of Phytopathology 15: 203-222
32

Objectives

Context

Study 4: Measuring Fungal Succession in Douglas-Fir Forests

Jane E. Smith, Randy Molina, Donaraye McKay, Michael 

Castellano, and Daniel Luoma1 2

The importance of ectomycorrhizal fungi to many ecosystem processes is well established, 

yet little is known about community structure and dynamics of ectomycorrhizal fungi in 

natural vegetation. This study was undertaken to determine whether ectomycorrhizal fungus 

communities differ between successional stages of Douglas-fir forests. Describing fungus 

communities by sampling sporocarps will provide data essential for predicting impacts of 

disturbance and management on forest health. Study results will provide information about 

factors critical to maintaining the diversity of ectomycorrhizal fungi regionally. Correlations 

between fungus populations and factors such as vegetation associations, soil types, stand 

age, stand density, or harvesting methods could be used to estimate sporocarp production in 

similar habitats during periods typical of forest succession. Insights about the relations 

among forest succession, disturbance, and ectomycorrhizal fungal diversity will provide for 

comparisons of sporocarp production in forests of the Pacific Northwest (Amaranthus and 

others 1994; Ammirati and others 1994; Fogel 1976; Fogel and Hunt 1979; Hunt and Trappe 

1987; Luoma 1989, 1991; Luoma and others 1991; Waters and others 1994), the northern 

Rocky Mountains (Harvey and others 1987, 1991), Europe (Arnolds 1981, Gáper and Lizon 

1995, Mehus 1986, Mikola 1962, Ohenoja and Metsänheimo 1982), and the United Kingdom 

(Dighton and others 1986). Because mushrooms and truffles are important food for small 

mammals, predictability of sporocarp production will influence forest management decisions 

directly affecting wildlife populations. Knowledge about the comparative ecological functions 

of various ectomycorrhizal fungi that colonize tree roots during different seral stages of forest 

succession is lacking and deserves additional investigation.

The objectives of this study were to compare the following among young, rotation-age, and 

old-growth Douglas-fir stands:

1. Species richness and biomass of epigeous ectomycorrhizal fungus sporocarp 

(mushroom) production.

2. Species richness and biomass of hypogeous ectomycorrhizal fungus sporocarp (truffle) 

production. (Truffle production will be correlated with abundance and decay class of 

1 Jane Smith, Randy Molina, Donaraye McKay, and Michael Castellano are with the U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331; and Daniel Luoma is with the Department of 

Forest Science, Oregon State University, Corvallis, OR 97331.

2Cooperators included Jim Mayo, USDA Forest Service, Willamette National Forest; Cascade Center for Ecosystem 

Management; and Oregon State University.
33

2. Percentage of cover of Piloderma bicolor, a widespread ectomycorrhizal fungus that 

does not produce mushrooms or truffles but can be identified by its thick, bright 

yellow mycelium in the soil. (Piloderma bicolorcoverage will be correlated with 

abundance and decay class of coarse woody debris, because it is thought to be 

associated with old-growth forests.)

Species diversity and sporocarp production of ectomycorrhizal mushrooms and truffles 

were examined from plots in three replicate stands each of old-growth (>400 years old), 

rotation-age (45-60 years old), and young (25-30 years old) Douglas-fir in and near the 

H.J. Andrews Experimental Forest along the west side of the Cascade Range in Oregon.

Stands were sampled once each in spring and autumn, 1991-94. Sampling in both spring 

and autumn was necessary to capture the dichotomy in seasonal fruiting patterns typical of 

the Pacific Northwest (Fogel 1976, Hunt and Trappe 1987, Luoma and others 1991). 

Sporocarp production varies annually so stands must be sampled for several years to 

detect fluctuations. Sporocarp sampling was timed to coincide with the peak of seasonal 

fruiting determined from weather reports and reports of field cooperators.

Ectomycorrhizal mushroom sporocarps were collected from a total area of 700 square 

meters (7,535 ft.2) per stand from strip plots (2 by 50 meters [6.6 by 164 ft.]) and circular 

truffle plots (study 3). Three of six strip plots were permanently located within each stand. 

Sporocarps of each ectomycorrhizal mushroom species were collected separately for each 

square meter of the permanent plots. Three temporary mushroom strip plots were 

positioned in the upper, middle, and lower slopes of each stand. Sporocarps of each 

ectomycorrhizal mushroom species were treated as a single collection for each temporary 

plot. Sporocarps were identified, dried, and weighed to the nearest 0.01 gram.

Truffles were collected from twenty-five 4-square-meter(43-ft.2) circular plots (a total area 

of 100 square meters [1,076 ft.2] per stand) located at 25-meter (82-ft.) intervals along 

three transects (eight, nine, and eight plots each, in the upper, middle, and lower slope 

strata, respectively). In each truffle plot, the percentage of cover by exposed mineral soil, 

coarse woody debris by decay class, and Piloderma bicolor mycelium was recorded. Data 

pertaining to coarse woody debris were measured according to methods described in 

study 3 with the exception that coarse woody debris = 10 centimeters (3.9 in.) rather than 

8 centimeters (3 in.) diameter was the criterion for this study. Truffle plots were marked 

with a flag to avoid repeat sampling of the same area in subsequent seasons. Sporocarps 

were identified, counted, dried, and weighed to the nearest 0.01 gram.

Sufficient rainfall is necessary to initiate autumn fruiting; hence, scheduling fieldwork then 

was more difficult than during spring, because predicting the onset of autumn rains or 

season-ending heavy frost or snowfall is not possible. The spring fruiting season is longer 

and more predictable than the autumn season.

Sampling was accomplished mostly with volunteer help, and many volunteers were 

available for only 1 or 2 days. Collecting is labor intensive and a crew of four to six

Methods and

Rationale

Unique

Considerations
34

people was required each sampling season (3 to 4 work weeks). This high degree of volunteer 

turnover required that more time be allotted to training and ensuring that data collection was 

consistent. The amount of time required to sample differs with crew experience, weather conditions, 

and density of understory vegetation.

Statistical analyses are in progress, as are final taxonomic determinations of problem taxa. 

Sampling will likely continue in subsequent years to substantiate trends reflected in this 4-year 

sample period.

Amaranthus, M.; Trappe, J.M.; Bednar, L.; Arthur, D. 1994. Hypogeous fungal production in 

mature Douglas -fir forest fragments and surrounding plantations and its relation to coarse woody 

debris and animal mycophagy. Canadian Journal of Forest Research. 24: 2157-2165.

Ammirati, J.; Ammirati, S.; Norvell, L. [and others]. 1994. A preliminary report on the fungi of 

Barlow Pass, Washington. Mcllvainea. 2: 10-33.

Arnolds, E. 1981. Ecology and coenology of macro-fungi in grasslands and moist heathlands 

in Drenthe, The Netherlands. Bibliotheca Mycologica. 83: 1-407.

Dighton, J.; Poskitt, J.M.; Howard, D.M. 1986. Changes in occurrence of basidiomycete fruit 

bodies during forest stand development: with specific reference to mycorrhizal species. 

Transactions of the British Mycological Society. 87: 163-171.

Fogel, R.; Hunt, Gary A. 1979. Fungal and arboreal biomass in a western Oregon Douglas-fir 

ecosystem: distribution patterns and turnover. Canadian Journal of Forest Research. 9: 

245-256.

Fogel, R. 1976. Ecological studies of hypogeous fungi. II: Sporocarp phenology in a western 

Oregon Douglas -fir stand. Canadian Journal of Botany. 54: 1152-1162.

Gáper, J.; Lizon, P. 1995. Sporocarp succession of mycorrhizal fungi in the Norway spruce 

plantations in formerly agricultural land. In: Baluska, F. [and others], eds. Structure and function 

of roots. [City unknown], The Netherlands. Kluwer Academic Publishers: 349-352.

Harvey, A.E.; Jurgensen, M.F.; Larsen, M.J.; Graham, R.T. 1987. Relationships among soil 

micro-site, ectomycorrhizae, and natural conifer regeneration of old-growth forests in western 

Montana. Canadian Journal of Forest Research. 17: 58-62.

Harvey, A.E.; Page-Dumroese, D.S.; Graham, R.T.; Jurgensen, M.F. 1991.

Ectomycorrhizal activity and conifer growth interactions in western-montane forest soils. In: 

Harvey, Alan E.; Neuenschwander, Leon F., eds. Proceedings: Management and productivity of 

western-montane forest soils; [Dates of meeting unknown]; [Location of meeting unknown]. Gen. 

Tech. Rep. INT-280. [Place of publication unknown]: U.S. Department of Agriculture, Forest 

Service: 110-118.

Current Status

Literature Cited
Luoma, D.L. 1991. Annual changes in seasonal production of hypogeous sporocarps 

in Oregon Douglas-fir forests. In: Ruggiero, L.F.; Aubry, K.B.; Carey, A.B.; Huff, 

M.H., tech. coords. Wildlife habitat relationships in old-growth Douglas-fir forests. 

Gen. Tech. Rep. PNW-GTR-285. Portland, OR; U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station: 83-89.

Luoma, D.L.; Frenkel, R.E.; Trappe, J.M. 1991. Fruiting of hypogeous fungi in 

Oregon Douglas -fir forests: seasonal and habitat variation. Mycologia. 83: 335-353.

Mehus, H. 1986. Fruit body production of macro-fungi in some north Norwegian forest 

types. Nordic Journal of Botany. 6: 679-701.

Mikola, P. 1962. The bright yellow mycorrhiza of raw humus. In: Proceedings of the 

13th Congress of the IUFRO; 1961 September; Vienna, Austria. [place of 

publication unknown]: [publisher unknown]: Part 1, 24-4: [page numbers unknown].

Ohenoja, E.; Metsänheimo, K. 1982. Phenology and fruiting body production of 

macro-fungi in subarctic Finnish Lapland. In: Laursen, G.A.; Ammirati, J.F, eds. 

Arctic and alpine mycology. Seattle; University of Washington Press: 390-409.

Waters, J.R.; McKelvey, K.S.; Zabel, C.J.; Oliver, W.W. 1994. The effects of 

thinning and broadcast burning on sporocarp production of hypogeous fungi. 

Canadian Journal of Forest Research. 24: 1516-1522.

35
Study 5: Inventory and Monitoring of Rare Fungus

Species: A Case Proposal

James Trappe and Michael Castellano 1 2

Protection of rare fungi and their habitat is a responsibility of forest managers and 

researchers alike. Inventory of populations of target fungi is the first step in a protec tion 

program, and monitoring for changes in populations is an important followup. The President's 

plan (USDA and USDI 1994) for Federal land management within the range of the northern 

spotted owl specifically directs the National Forests and Bureau of Land Management districts 

to survey for rare fungus species before implementing disturbance activities. These survey 

procedures are currently being designed. We have selected an area to exemplify proposed 

methods for inventory and monitoring of rare fungi: the Lamb Butte Scenic Area in the 

Willamette National Forest. Similar procedures can be adapted to other sites of rare fungi.

Objectives of the study are to:

1. Provide reasonable interim protection to areas with known rare fungi.

2. Test procedures for surveying known populations of rare fungi for mapping population 

boundaries and establishing appropriate reserves.

The Lamb Butte Scenic Area contains at least two rare, local endemics (Chroogomphus 

loculatus and Gastroboletus imbellus) and other rare but not locally endemic species (Trappe, 

unpublished data). A stepwise approach is proposed. Year 1: Examine, define, and map 

habitat types characteristic for the rare species over the entire ridge system that connects 

Lamb Butte with nearby Ollalie Ridge Research Natural Area. All areas in the ridge system 

with the appropriate habitat types plus 40-meter (1,300-ft.) buffer strips will be temporarily 

withdrawn from management activities. The withdrawal will continue until inventories reveal 

the extent of the populations of the rare fungi and the habitats in which they occur. 

Populations of the rare species will be inventoried in either the spring or autumn fruiting 

season, depending on the life-cycle of the particular fungus. The mapped habitats, buffer 

strips, and areas adjacent to clearcut edges or encircling roads will be carefully searched for 

the target species. All finds of rare fungi will be entered on the habitat type maps. Weather 

patterns before and during the fruiting season of target species will be recorded. Year 2: 

Repeat inventory as for year 1. Year 3: Repeat inventory as for year 1 unless populations of 

the target fungi have been well defined. Year 4: Define boundaries of area to be withdrawn 

and complete withdrawal process for a mycological preserve; include rare fungi in inventories 

of watersheds in the general area. Years 5 and thereafter: Monitoring will be continued in 

year 5 and at periodic intervals thereafter, depending on weather patterns found to be 

favorable for fruiting of the target fungi by previous inventories.

1James Trappe is with the Department of Forest Science, Oregon State University, Corvallis, Oregon; and Michael 

Castellano is with the U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Corvallis, 

Oregon.

2Cooperators were Willamette National Forest, Oregon Mycological Society, North American Truffling Society, and the Native 

Plant Society.

Context

Objectives

Methods and 

Rationale

36
37

Fruiting differs from season to season and year to year. We cannot presently predict when a 

given fungus species will fruit. Hence, inventory must begin as soon as the sites become wet 

enough to sustain autumn fruiting, 2 weeks after the first wetting rains, and every 2 weeks

thereafter until the first hard freeze or snow covers the ground. Spring-fruiting species should 

be monitored at 2-week intervals from time of snowmelt until summer drought. If the summer 

is wet, inventory may continue through the summer at manageable intervals. If populations 

of the target or other rare fungi have been discovered and mapped in years 1 and 2, 

withdrawal can be completed in year 3. If the populations have not been defined by the end 

of year 3, the withdrawal area will be defined by habitat type of the type localities with 

400-meter (1,300-ft.) buffer strips.

Research and National Forest personnel must collaborate to ensure that all individuals 

involved in the inventory and monitoring are adequately trained and provided with written 

descriptions and illustrations of the target fungi and other rare fungi that have been found in 

similar habitats elsewhere. Interested individuals from the mycological and native plant 

societies will be recruited to help; otherwise the limited available personnel from research 

institutions and National Forests may not be able to complete the program in an acceptable 

intensity and time.

As managers of the area, personnel of the Willamette National Forest will be responsible 

for organizing and implementing inventories, withdrawing and protecting areas involved, 

and subsequent monitoring. One professional mycologist or more will work closely with 

National Forest personnel to train assistants and oversee mycological aspects of inventory 

and monitoring.

Unknown factors, presumably including history, geology, soils, vegetation, and climate, have 

combined to produce an unusual concentration of rare and locally endemic fungi in the Lamb 

Butte-Ollalie Ridge area. Probably the same combination of factors has provided habitat for 

other rare organisms as well. Unknown factors complicate definition of the area to be 

preserved. Target fungi are known only from single-type collec tions, so extent of soils, 

mycorrhizal hosts, and habitat types are unknown. Sporocarps of the target fungi are shortlived, and weather patterns that induce and shut down fruiting are difficult to determine; 

hence 2-week sampling periods may be inadequate to encounter fruitings of these species.

Many areas of the Western United States contain rare fungi, and each area will have its own 

distinctive characteristics. This example can serve as a starting point for inventory and 

monitoring of rare fungi, but can be modified to meet the individual circumstances of other 

areas.

On July 5 and 6, 1994, a meeting of western professional mycologists convened in Corvallis, 

OR, to discuss the implications of growing interest in the surveying of rare fungus species, 

especially the shortage of taxonomists and the training that will be required for field crews. 

Currently, a Federal interagency team is finalizing standard protocols for surveying rare fungi 

on Federal lands in the Pacific Northwest. Amy Rossman, Director of the National Fungus 

Collection, Agricultural Research Service, Beltsville, MD, sponsored a workshop on October 

15-19, 1995, to begin work on a book outlining sampling protocols for all fungal taxa.

Current Status

Unique

Considerations
38

Miller, O.K.; Trappe, J. 1970. A new Chroogomphus with a loculate hymenium and 

a revised key to section Floccigomphus. Mycologia. 62: 831-836.

Thiers, H.T.; Trappe, J.M. 1969. Studies in the genus Gastroboletus. Britonia. 21: 

244-254.

U.S. Department of Agriculture, Forest Service; U.S. Department of the 

Interior, Bureau of Land Management. 1994. Final supplemental environmental 

impact statement on management of habitat for late-successional and old-growth 

forest related species within the range of the northern spotted owl. [Place of 

publication unknown]. 2 vol.

Literature Cited
39

Study 6: Influence of Thinning, Plant Diversity, 

and Mycophagous Mammals on Mycorrhizal 

Fungi

Wes Colgan III, James Trappe, Randy Molina, Andrew B. Carey, and 

David Thysell 1 2

The northern flying squirrel is the major food of the northern spotted owl in the Puget 

Sound area of Washingt on. The squirrel feeds almost exclusively on hypogeous 

sporocarps (truffles and truffle-like fruiting bodies) of fungi that are ectomycorrhizal 

with Douglas-fir and western hemlock. As part of an integrated study, "Experimental 

manipulation of managed stands to provide habitat for spotted owls and to enhance 

plant and animal diversity," at the Fort Lewis Military Reservation, WA, we are 

examining short-term effects of thinning, provision of nest boxes, and a combination of 

the two on diversity and productivity of hypogeous ectomycorrhizal fungi and their use 

as food by northern flying squirrels.

The objectives are to:

1. Determine seasonal species composition and standing crop biomass of 

hypogeous and selected epigeous ectomycorrhizal fungus sporocarps in nonthinned, lightly-thinned, heavily-thinned, and open-cut areas, with and without tree 

cavities and nest boxes, of four treatment blocks.

2. Determine the seasonal diet of flying squirrels live-trapped in non-thinned and 

thinned stands throughout the year through fecal pellet analyses of the percentage 

of fungus, plant, and lichen components.

The study consists of 16 stands of 55- to 65-year-old plantations of Douglas-fir. Eight 

stands have been thinned twice (1972 and late 1980s) and eight have not been thinned 

since planting. Four of each stand type were thinned in February and March 1993. 

Biomass production and species composition of hypogeous and epigeous sporocarps 

in treated and untreated stands are being measured. Diets of flying squirrels in treated 

and untreated stands are being assessed by analyses of feces collected from livetrapped individuals. Available sporocarps will be compared to those actually consumed 

by squirrels in the stands to determine if the squirrels prefer certain species.

The sampling method chosen is adapted from Luoma (1991). Statistical analysis will 

provide estimates of stand-level fungus characteristics (seasonal sporocarp standing 

crop, annual biomass production, species diversity, and so forth).

Methods and 

Rationale

Objectives

Context
Field sampling was done about every 6 weeks from April 1993 through December 1995. At the 

first sampling, all stands without tree cavities or nest boxes were sampled; at the second 

sampling 6 weeks later, all stands with tree cavities and nest boxes were sampled. This 

alternation continued throughout the study. Fungus sporocarps were collected from 10 circular 

plots, each 4.0 square meters (43 ft.2), located at about 10-meter (32.8-ft.) intervals along 

randomly placed transects in each of the non-thinned stands of each block at each sampling 

time. Thinned stands of each block were sampled more intensively to determine if thinning 

treatments affect sporocarp produc tion differently. Each treatment (light thin, heavy thin, and 

open cut) was sampled by 10 randomly placed 4.0-square-meter (43-ft.2) plots, totaling 30 plots 

per thinned stand per sampling period.

Epigeous sporocarps (mushrooms) of species eaten by small mammals (primarily the 

Boletaceae and Russula spp.), and other mycorrhizal fungi observed or suspected to be used as 

food by small mammals, were collected from each plot. Each item was placed in a waxed paper 

bag with a tag recording plot number, stand number, and other pertinent information. Each plot 

was then raked to a depth of at least 5 centimeters (2 in.) into mineral soil to expose hypogeous 

sporocarps. Position in soil profile, distance to nearest coarse woody debris, and field 

characteristics (bruising reactions, odor, and so forth) were recorded. All plots were marked with 

a flag and the duff replaced. No plot was sampled twice. All fungus samples were annotated, 

dried, and returned to the Forestry Sciences Laboratory, Corvallis, OR, for final identification and 

weighing. Voucher specimens of each species found were deposited in the mycological herbarium at Oregon State University (OSC3

).

Fecal pellets collected from live -trapped animals at Fort Lewis are being microscopically 

analyzed for spores and other food remnants. Fort Lewis cooperators preserved the pellets 

with ethanol and provided animal identification numbers and stand data. Fungus spores were 

identified to genus or to species when possible. Frequency and relative quantity were 

estimated. Types of vascular plants and lichens were recorded and identified when possible 

(Castellano and others 1989).

The ratio of fungi to plants and lichens found in feces of animals will be plotted through the year 

to determine seasonal variation. Sporocarps present in the field during a given sampling time 

will be compared to species in fecal pellets collected at the same time. These comparisons will 

determine whether some species are being found by the animals but not by researchers and 

whether fungus caches are being used for food.

This study is the first to examine effects of silvicultural manipulation of managed forests on 

sporocarp production of mycorrhizal fungi and the animals that feed on them. As part of the 

larger silviculture and wildlife study at Fort Lewis, it is also the first to integrate data on fungus 

productivity and squirrel feeding behavior. It will greatly enhance understanding of the 

importance of mycorrhizal fungus sporocarps in forest food webs.

Comparing sporocarps present in stands immediately after thinning to sporocarps found in 

undisturbed stands will reveal short-term effects of thinning on the fungus community. The data 

can be compared to a similar study of fungus sporocarp produc tivity at the Siskiyou National 

Forest Integrated Research Site in southwest Oregon (study 2). The small mammal mycophagy 

portion of our study will allow comparisons to data collected in the Olympic Mountains in 

Washington (Carey, in press) and the Coast Ranges of Oregon (Maser and others 1978).

3The original acronym, OSC, for Oregon State College has been retained to refer to the herbarium at Oregon State University 

(OSU).

40
41

The study at Fort Lewis is an integrated ecosystem management study. Coordination 

with the many other researchers is essential. Our study must fit within the goals of the 

long-term study.

Our study was installed as the thinning was completed. Now, in the third year posttreatment, dense underbrush and weedy species are filling the gaps created by the 

logging operation. This situation creates undesirable conditions for workers and crew 

managers. A large brush saw is necessary to clear plots and, often, the paths between 

them. Field personnel must be made aware that stinging nettle and yellow jacket 

wasps are hazards often encountered in the field.

We continue to analyze fecal pellets, and field data are undergoing statistical 

analyses. This project would not be possible without the many volunteers from the 

Puget Sound area. At present, more than 50 species of hypogeous fungi have been 

collected from study plots; at least 5 are new to science.

Carey A.B. [In press]. Sciruids in Pacific Northwest managed and old-growth 

forests. Ecological Applications.

Castellano, M.A.; Trappe, J.M.; Maser, Z.; Maser, C. 1989. Key to the spores of the 

genera of hypogeous fungi of north temperate forests. Eureka, CA: Mad River 

Press: 186 p.

Luoma, D.L. 1991. Annual changes in seasonal production of hypogeous sporocarps 

in Oregon Douglas-fir forests. In: Ruggiero, L.F.; Aubry, K.B.; Carey, A.B.; Huff, 

M.H., tech. coords. Wildlife habitat relationships in old-growth Douglas-fir forests. 

Gen. Tech. Rep. PNW-GTR-285. Portland, OR; U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station: 83-89.

Maser, C.; Trappe J.; Nussbaum, R.A. 1978. Fungal-small mammal 

interrelationships with emphasis on Oregon coniferous forests. Ecology. 59(4): 

799-809.

Unique

Considerations

Current Status

Literature Cited
42

Productivity and Sustainable Harvest of Wild 

Mushrooms

Michael Amaranthus and David Pilz 1

Throughout history, mushrooms have been important sources of food and medicine. In the 

Pacific Northwest, however, only recently has demand for wild mushrooms grown sharply. 

About two decades ago, enterprising individuals began harvesting and shipping fresh 

chanterelle mushrooms to fine restaurants and gourmet shops in California and along the East 

Coast. It was a small and scattered industry where harvesters sold and shipped the majority of 

the harvest. The season ranged from 2 to 3 months in autumn, and the volume of mushrooms 

harvested was relatively small.

Major changes occurred by the late 1980s in the volume and manner in which mushrooms 

were harvested, sold, and handled. Chanterelles were sold primarily to European markets and 

canneries rather than restaurants. The industry expanded to a system of harvesters, buyers, 

processors, and brokers. Harvesters located and picked the mushrooms. Buyers, typically 

associated with a specific processor, set up buying stations near wooded areas known to 

produce mushrooms and advertised for harvesters. Processors handled, cleaned, packed, 

and shipped the product, while providing the cash and field prices. Brokers marketed the 

processed mushrooms around the world.

During this period, supplemental income from wild mushroom harvesting grew substantially for 

unemployed timber industry and other rural workers (Chen and others 1993). In 1992 nearly 

11,000 people, employed full or part time, contributed over $41.1 million to the economies of 

Oregon, Washington, and Idaho by harvesting and selling nearly

1

 Both authors are with U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station; Michael Amaranthus

is at Grants Pass, OR 97526 and David Pilz is at Corvallis, OR 97331.

Historical Context
43

1.82 million kilograms (4 million pounds) of wild edible mushrooms (Schlosser and Blatner 

1995). Pickers generally earned from $2 to $100 per pound, depending on species, 

quality, and supply.

Today, thousands of pickers harvest commercial fungi from private and public lands, yet 

uncertainty about the ecology of wild edible mushrooms hinders efforts to manage this valuable 

resource. At the center of the management issue is a lack of information on the ecology of 

these forest fungi, productivity and habitat requirements, interaction of forest health and 

mushroom production, and the effects of repeated mushroom harvest on production. Clearly, if 

wild edible mushroom production is to be sustained, it must be done by understanding these 

organisms and the social and economic forces behind their harvest (U.S. Department of the 

Interior 1993).

The suitability of a particular mushroom species for commercial harvest depends on many 

criteria including abundance, shelf life, appearance, texture, flavor, and familiarity to sellers 

and buyers. Schlosser and Blatner (1995) state that over 25 species are harvested for resale in 

the Pacific Northwest. The Integrated Resources Policy Branch of the British Columbia Ministry 

of Forests lists 22 edible mushroom species commercially harvested from their forests (de 

Geus 1995). Large-scale commercial harvest, however, is concentrated on the following 

species, given in declining order from greatest to least cash value of the harvest. For more 

information on the 1992 Pacific Northwest commercial wild mushroom market cited below, see 

Schlosser and Blatner (1995). For a more detailed discussion of each species and further 

technical references, see Molina and others (1993).

The American matsutake (Tricholoma magnivelare) is cousin to the highly prized Japanese 

"pine mushroom" (T. matsutake). It forms ectomycorrhizae over a broad geographical area in 

association with a wide variety of tree species in the Pacific Northwest including true firs, 

pines, Douglas-fir, hemlock, and tanoak (Lithocarpus). The North American harvest begins in 

August, in British Columbia, and continues south to northern California, in January. Small 

quantities of matsutake mushrooms are harvested in Mexico in Pinus teocote forests during 

summer and autumn.2 The annual harvest from the Pacific Northwest has increased 

dramatically in recent years because of the high market value. In 1992, nearly a million pounds 

were harvested. Price to harvesters ranges greatly, depending on the developmental stage of 

the mushroom. Japanese buyers, the primary market, prefer young specimens, and prices 

paid to pickers occasionally reach $100 a pound. The average price in 1992 was over $8 a 

pound averaged for all stages of development or "grades," but in some years it has been much 

higher.

Morels (Morchella species) are not generally mycorrhizal (see study 7 for discussion). They 

seem to fruit most prolifically in open woodlands, mixed-conifer forests, hardwoods, and 

disturbed areas, especially following fire or tree mortality. In the Pacific Northwest, fruiting 

begins as early as February in warm areas and continues into June in cool areas. Oregon 

produced an estimated 400,000 kilograms (900,000 lbs.) in 1992.

2Personal communication. 1995. Luiz Villareal, Instituto de Recursos Geneticos y Productividad, 

Montecillos, Mexico.

Species of

Mushrooms

Harvested

Matsutake

Morels
44

The harvest fluctuates greatly from year to year depending on abundance. Many areas are 

crowded with pickers after fires. For morels, pickers earned about $4 a pound in 1992, but many 

restaurants pay in excess of $25 a pound for fresh morels.

The chanterelle (Cantharellus cibarius Fr.) is an ectomycorrhizal symbiont with several forest 

trees. It commonly associates with Douglas-fir and hemlock in the Pacific Northwest. In the 

United States, commercial harvest begins in August on the Olympic Peninsula of Washington 

and continues into December in northern California. Over a million pounds are marketed from 

the Pacific Northwest annually. The picker earned about $3 a pound in 1992. Price for 

chanterelles leaving the area is considerably higher. Wholesale prices in San Francisco 

exceeded $20 a pound in autumn 1994. Other areas, such as Poland and Russia, are major 

exporters of the chanterelle. The percentage of total market demand that is harvested in the 

Pacific Northwest is unknown.

Many species of Boletus mushrooms are hunted by recreational pickers. One species, Boletus 

edulis, is highly esteemed by Europeans and therefore commercially valuable. Boletus edulis is

an ectomycorrhizal symbiont with spruces, pines, Douglas-fir, true firs, and some oaks. 

Commercial harvest of this mushroom is still limited, but increas ing. It fruits most abundantly in 

early autumn, but spring and early summer fruitings are common in some areas. Price was 

about $4.50 a pound fresh to harvesters in 1992 but differs with grade. Young specimens 

generally sell for over $10 a pound.

The Oregon black truffle (Leucangium (Picoa) carthusiana) has a pleasant odor reminiscent of 

pineapple and is widely collected in Douglas-fir forests. Over 18,000 kilograms (4,000 lbs.) were 

collected in Oregon alone, in 1992, and price per pound to pickers averaged $75. The Oregon 

white truffle (Tuber gibbosum) is reminiscent of the Italian white truffle of Europe, although its 

taste and ecology differ significantly. It is ectomycorrhizal with Douglas-fir. About 32,000 

kilograms (7,000 lbs.) were harvested from Oregon and Washington in 1992, with prices 

averaging about $30 per pound. October through December are peak fruiting periods for these 

species. Truffles fruit beneath the soil surface, and thus their presence and maturity are hard to 

detect without the use of trained sniffing animals such as the dogs or pigs used in Europe for 

truffle harvesting. Regional, national, and international demand for ripe truffles is high, and 

inoculation of tree plantations with European species of truffles has been attempted in California, 

Oregon, North Carolina, Texas, New Zealand, and Tasmania (Smith 1995, Trappe 1988). To 

date, production of European truffles has been verified in the North Carolina, California, and 

New Zealand plantations.3 Markets for wild Pacific Northwest truffles have been slow to develop, 

however, because some early marketing attempts included immature and relatively odorless 

truffles found by random raking, rather than only ripe and pleasantly aromatic specimens found 

by trained animals.4 Ripe specimens of Pacific Northwest truffles are very flavorful, though, and 

their potential market remains large.

3Personal communication. 1995. Mike Castellano, USDA Forest Service, PNW Research Station, 

3200 Jefferson Way, Corvallis, OR 97331.

4Personal communication. 1994. James Trappe, Department of Forest Science, Oregon State 

University, Corvallis, OR 97331.

Chanterelles

Boletes

Truffles
Hedgehogs (Hydnum repandum and H. umbilicatum are ectomycorrhizal symbionts with 

Douglas-fir and other forest trees. Hedgehogs fruit from autumn until late spring. Many 

consumers are still unfamiliar with hedgehogs, and they have a relatively small commercial 

trade. About 18,000 kilograms (40,000 lbs.) were harvested in 1992 with the price averaging 

about $3 per pound. Mushroom companies are seeking to expand harvest of this species.

Mushroom harvesters range from the curious or avid recreationalist to temporarily unemployed 

workers needing additional income, to highly skilled commercial harvesters. Individuals who 

work in forestry or timber harvesting often are familiar with fruiting locations and enjoy being in 

the woods; hence, they can easily supplement income during periods of slack employment by 

collecting and selling mushrooms. Recent immigrants, especially Southeast Asians, can 

harvest mushrooms profitably without the language skills and education required for other jobs. 

Native Americans claim prior harvesting rights in some instances; the Karuk Tribe in northern 

Californian and the Nisga'a Tribe in the Nass Valley of northern British Columbia6 have both 

claimed prior rights to matsutake harvesting.

Valuable mushrooms (matsutake) or mushrooms that fruit in large flushes (morels) often are 

harvested by transient mushroom gatherers who travel to new locations as the season 

progresses; for instance, matsutakes begin fruiting in northern Canada in August and may 

end in the mountains of coastal California in January. Morels can begin fruiting as early as 

February in southwest Oregon. In the forests of the intermountain West, morels 

progressively appear at higher elevations and on more northerly aspects (as late as June 

and July) as weather warms and snowpacks melt. In contrast, the less valuable chanterelle 

can fruit for up to 5 months in a single location (study 8) and is typically picked by local 

harvesters.

Even remote areas may experience commercial harvest of valuable species. Helicopters are 

routinely used to transport matsutake collected in roadless areas of interior British Columbia 

(see footnote 6). By comparison, the practicality of selling low-value chanterelles often 

depends on how far a picker has to drive between the collection site and a buyer; thus 

relatively inaccessible areas are unlikely to experience significant commercial harvesting 

when prices are low.

Wild, edible mushrooms from Washington, Oregon, and Idaho are being marketed around the 

world as well as nationally and locally. Japan is the predominant market for matsutake, 

followed by Asian communities in the Western United States and Canada. Europe is the 

largest international market for chanterelles, although imports differ widely by country. Morels 

are predominantly marketed within the United States, but international markets include 

Europe, Japan, and Canada (Schlosser and Blatner

5

0ctober 28, 1993, correspondence by Stephen H. Suagee, Attorney at Law, to Barbara Holder, Forest Supervisor, Klamath National 

Forest, in reference to the Karuk Tribe's Notice of Appeal and Request for Stay of the October 20, 1993, Decision Notice and Finding 

of No Significant Impact (FONSI) for [Tanoak] Mushroom Management by District Rangers George R. Harper and Sam Wilbanks for 

the Happy Camp and Ukonom Ranger Districts, Klamath National Forest, California, respectively. On file with: Klamath National 

Forest, 1312 Fairlane Road, Yreka, CA 96097.

6

de Geus, Nelly; Redhead, Scott; Callan, Brenda. 1992. Wild mushroom harvesting discussion session minutes, March 3, 1992. 

Report on file with: Integrated Resources Branch, British Columbia Ministry of Forests, Pacific Forestry Centre, Victoria, BC.

45

Hedgehogs

Economic and 

Social Factors
1995). Barring major disruptions to international trade, markets for wild edible mushrooms 

are likely to continue growing as human populations increase and become more affluent, and 

as more people become familiar with the pleasures of their consumption (Molina and others 

1993).

Matsutake, morels, and chanterelles are commercially collected elsewhere throughout the 

Northern Hemisphere, resulting in significant international competition. International markets 

and prices can fluctuate wildly from year to year, and even within a season, as global weather 

patterns produce good or poor crops in various locations. Competition or collusion among 

mushroom buyers and processors can dramatically influence prices paid to local harvesters. 

Prices paid to pickers can inflate tremendously when mushroom crops are poor elsewhere, 

good locally, and buyers compete intensely. This is particularly true of high-value mushrooms, 

such as matsutakes. When prices are high, it is not unusual for large numbers of harvesters 

to congregate in small areas, sometimes to the consternation of land managers and the local 

communities.

Although harvester groups, travel arrangements, and market forces fluctuate, mushroom 

harvesting job opportunities have become important to local and regional economies. Of the 

estimated 11,000 commercial harvesters in 1992, 35 percent reported that mushroom 

harvesting was their primary source of income during the fruiting season (Schlosser and 

Blatner 1995).

We are just beginning to develop quantitative estimates of the commerce in wild mushrooms. 

Much economic misinformation exists about the mushroom industry. This results from erratic 

mushroom fruiting patterns from year to year that can greatly influence supply and price. 

Also, the popular press tends to use high prices present at the beginning or end of the 

season as a standard for the entire season. This overestimates real cash amounts that 

harvesters receive. Little information is available about the percentage of family income 

derived from mushroom harvesting or total dollar amount generated in the region. Mushroom 

harvest dollars are often part of an "underground" economy in which much of the cash value 

is not reported. Even though the income is not reported, harvesters spend substantial dollars 

in a rural communities. Many Asian pickers leave large urban environments and travel long 

distances to small rural communities where they stay for a few days to several weeks. During 

this period, harvest dollars benefit local communities.

Harvesting wild edible mushrooms in the Pacific Northwest is attracting international 

attention as a tourist activity. A "package mushroom tour" for Japanese and other foreign 

visitors is being developed by one outdoor recreation company in Oregon. International 

tourists would be guided throughout the Northwest to pick a variety of mushrooms in 

majestic forests, experience local settings and customs, and have the mushrooms 

prepared by master chefs. The demand for such activities is likely to increase as harvest of 

wild edible mushrooms declines in heavily populated areas overseas.

Commercial mushroom harvesting has created regulatory issues across the Pacific 

Northwest.7 Concerns include over-harvesting, undesirable harvest methods, competi7Russell, Kenelm. 1990. Forest fungi manufacturing, marketing, and regulatory considerations. Presented at 

the special forest products workshop, Portland, OR, February 8-10, 1990. On file with: K. Russell, Washington 

State Department of Natural Resources, Olympia, WA 98504.

46
47

tion among harvesters for "picking rights," wildlife harassment, traffic safety and 

road repairs, campground crowding and maintenance, littering, trespass, firearm 

safety, vandalism, and research site security. In response to locally abundant 

mushroom crops, sudden large influxes of harvesters and buyers can quickly stress 

community and management resources.

Regulations for protecting the mushroom resource may take the form of implementing 

harvest rules and permit systems, limiting permit numbers, allocating or rotating 

collection areas, or providing contracts for exclusive harvest rights. Prevention of 

inappropriate harvest methods requires communication through meetings, videos, 

posters, handouts, press releases, presentations, and other public education efforts. 

Road closures may be necessary to control traffic, road deterioration, and wildlife 

harassment or to protect research and monitoring areas. Law enforcement is needed 

to deter unauthorized or illegal activities in the forest. Large numbers of harvesters and 

avid competition for a valuable commodity can increase the potential for crime, and 

because buyers often handle large amounts of cash, they are tempting targets for 

robbery.

Effective management of the commercial mushroom harvest requires anticipating the 

size of the demand, primary locations of the activity, and expected conflicts. Public 

land managers must develop means to apportion the harvest fairly, while ensuring 

that harvesting impacts are minimized. Detailed information from the public is needed 

to make equitable decisions. Cooperation among Federal agencies to standardize 

permits, regulations, and procedures will reduce confusion and inconvenience among 

harvesters facing a maze of regulatory details specific to local forests or management 

districts. Law enforcement agencies, including Federal, state, county, and local, need 

access to information about permits, closed areas, and proper harvesting activities.

Most mushrooms harvested by commercial pickers are from Federal and state lands. 

Boise-Cascade, Weyerhaeuser, International Paper, Plum Creek, Simpson, and other 

industrial landowners also experience some commercial harvesting on their properties. 

All land managers play key roles in the future of the industry, because their silvicultural 

decisions influence the abundance and distribution of wild mushroom crops and they 

regulate access to their forests. Most managers recognize that wild mushrooms are an 

important forest product, both economically and ecologically. They also realize that 

little quantitative information is available as a basis for management decisions.

Extensive timber and mushroom harvesting has led to concern about the sustainability 

of the commercial wild mushroom harvest among a growing number of mycologists, 

forest managers, recreational pickers, commercial harvesters, buyers, and processors 

(Molina and others, in press, a). There is additional concern that mushroom harvesting 

at current rates could adversely affect forest health and productivity or food webs for 

wildlife species. Unfortunately, few benchmark measurements of commercial mushroom production exist to make comparisons of effects over time. As a result, agencies 

in the Pacific Northwest, such as the USDI National Park Service, USDA Forest Service, and the Washington Department of Natural Resources, are restricting mushroom 

harvest in some areas due to uncertainty over mushroom production and harvest 

impacts. Increased regulation and legislative appeals are likely.

Human Influences on 

Edible Mushroom 

Production
Much concern about the sustainability of the commercial mushroom harvest comes from 

European studies where a decline in populations of mycorrhizal fungi has been measured 

over the last three decades (Arnolds 1988, 1991). Arnolds (1988) found, however, no 

evidence that the collection of mushrooms by harvesters leads to a decline in fungus 

species abundance. Other factors may be involved; for example, forest habitat altered by 

agriculture and urban development has led to changes in fungus composition. The dramatic 

mushroom decline in recent decades has outpaced the loss or alteration of habitat, or 

changes in forest age, composition, and structure.

The observed fungus decline in central Europe also has been linked to increases in various 

types of pollution (Arnolds 1988). Decline in Cantharellus cibarius has been documented in 

The Netherlands and correlated to acid rain deposition patterns but not to mushroom 

harvesting (Danell 1994, Jansen and van Dobben 1987). Acid precipitation, caused by 

burning high-sulfur coal for power generation, has been linked to European temperate forest 

decline and directly influences ectomycorrhizal fungi (Dighton and others 1991, Oren and 

others 1989). Pollutants from heavy industry not only harm trees directly but also damage 

the soil and mycorrhizal fungi associated with the trees (Kowalski 1987). Heavy industrial 

pollution and shifts in fungus production have been documented in Germany and the former 

Czechoslovakia (Vosatka and others 1991). The level of mycorrhizal infection decreased 

significantly in a survey of conservation sites in Great Britain (Woodin and Farmer 1993). 

Increasing evidence and concern over decline of fungi in Europe have resulted in a series of 

international meetings and draft conservation strategies.

European mycologists have alerted their Pacific Northwest counterparts to the need to 

monitor wild edible fungi; however, sulfur dioxide pollutant levels in the Pacific Northwest are 

much lower than those observed in Europe, where fungus decline has been noted. American 

scientists determined that sulfur dioxide levels in the United States and Canada were lower 

by a level of magnitude compared to central Europe (MacKenzie and EI-Ashry 1990). Air 

pollutant sources of nitrous oxides and ozone can alter mycorrhizal symbiosis and 

mushroom production (Garner and others 1989, MacKenzie and EI-Ashry 1990), yet it is 

unknown whether observed nitrous oxides and ozone values typical of the Pacific Northwest 

could influence production of wild edible mushrooms. Wide distribution, natural variability in 

production and uncertain estimates derived from variable sampling protocols have made it 

difficult to document changes in production. Assessment is difficult because no accurate 

species distribution maps are available for wild edible mushrooms, and fungus populations 

remain unexplored in large areas of the Pacific Northwest.

The impact of improperly harvesting wild mushrooms has received substantial media 

attention over the last few years (Lipske 1994, McRae 1993, Richards 1993) and studies 8, 

9, and 11 in this document assess the impacts of various harvesting techniques. Certain 

practices such as raking and using leaf blowers to expose the young "buttons" of valuable 

matsutake have been specifically identified as potentially damaging to the matsutake 

mycelial mat. Other potentially harmful activities include forest floor compaction and 

resultant mycelium damage in heavily trampled areas or removing all sporocarps before 

spores are disseminated. No quantifiable information currently supports claims that these 

activities reduce production, however. Many mycolo48
gists believe that harvesting mushrooms is as harmless as picking fruit off a tree or berries 

from a bush. Careful and long-term monitoring is needed to determine if raking, trampling, and 

reduced spore production are damaging to the fungi (studies 9 and 11; Molina and others, in 

press, b).

Forest age, composition, and structure likely influence wild edible mushroom production, and 

there is great potential to manage forest stands to produce conditions that favor fruiting of a 

preferred mushroom species. Matsutake in Japan fruits most abundantly in 30- to 60-year-old 

pine stands, and Japanese foresters clear out understory vegetation, reduce litter depth, and 

thin trees to increase matsutake production. Clearly, morel production is stimulated by fire, 

and Oregon white truffles increased dramatically in size and abundance following the addition 

of lime to a Douglas-fir plantation.8 Forest management activities such as weed control, 

density management, prescribed underburning, and altering forest structure and composition 

to promote host species for certain wild edible fungi may be used as tools to enhance 

production in the future. The economic benefits during a rotation could be substantial, 

especially for highly valued commercial fungi such as matsutake, morels, and the Oregon 

white truffle.

Clearcutting impacts ectomycorrhizal mushrooms in the short term by killing major 

photosynthetic hosts and removing much of the energy source for sporocarp produc tion. 

Either surviving mycelium or spores from elsewhere may colonize the roots of new trees, 

but several decades typically pass before edible ectomycorrhizal species fruit again. Recent 

research indicates that clearcutting can decrease hypogeous sporocarp production 

compared to mature forest fragments (Amaranthus and others 1994). Over time, even-aged 

young forested stands that develop after clearcutting may, however, produce a greater 

abundance of some wild edible mushrooms species than the previous older forests 

(authors, personal observations, and discussions with harvesters).

A variety of wildlife consume matsutakes, chanterelles, and boletes, yet we poorly understand 

the role of mushrooms in their diets and whether mushroom harvesting by humans 

consequently reduces their food supplies. If these mushrooms are a signifi cant wildlife food 

resource, then human competition for them may affect specific wildlife populations. For 

instance, one forester has asked whether matsutake harvesting should be restricted near 

northern spotted owl nest sites on the supposition that flying squirrels (a main item of the 

spotted owl's diet) might feed on the mushroom. Conversely, mycophagy by indigenous 

wildlife species might be an important spore dispersal mechanism in certain locales. In 

southwest Oregon, for example, commercial collectors claim that matsutake mushrooms 

often are found fruiting near dusky-footed wood rat (Neotoma fuscipes) nests, and they 

speculate that new colonies are formed through dispersal of spores in wood rat feces. Deer 

and elk also actively seek matsutakes and can consume large quantities. The importance of 

this mushroom in their diet and whether they act as spore vectors are unknown.

Large numbers of mushroom hunters also may impact other resources, and some areas 

may need protection from mushroom harvesting. Traffic associated with heavy harvesting 

can have adverse effects on areas prone to high levels of erosion.

8Personal communication. 1993. James Trappe, Department of Forest Science, Oregon State University, Corvallis, Oregon 

97331.

49
50

Site Selection and Security

Research Challenges 

and Considerations

Matsutake harvesting in the Oregon Dunes National Recreation Area may be threatened by the impact of people walking on the highly erosive sandy soils. Moving slowgrowing moss to search for young "buttons" of matsutake mushrooms may significantly 

disturb habitat in the sandy soils of the Oregon Dunes, whereas moving leaves for the 

same purpose in the Siskiyou Mountains may be innocuous. Human trampling of locally 

endemic sensitive plant or fungus species may be a concern in some areas. Special 

habitats such as wetlands or areas containing habitat for rare plants or animals may 

need mushroom harvesting restrictions. It may be necessary to set up no-harvest areas 

as controls to examine the effects of harvest or rotate areas to minimize the impact of 

continued harvest.

Management concerns about movement of disease organisms also can influence 

mushroom harvest regulations. An appeal against commercial matsutake harvesting in 

the Klamath National Forest in northern California was based on fears that large 

numbers of pickers in the forest would increase the spread Phytophthora lateralis, a 

soil-borne root disease fatal to Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murr.) 

Parl.), into non-infected areas (see footnote 5).

Many management concerns regarding mushroom harvesting are actually concerns 

about managing people when they visit the forest. Demographic information from 

collection permits, industry surveys, public meetings, site visits, and interagency 

communication are all effective means of improving the regulation of human activities 

and serving the public.

Investigators who study a single species of edible mushroom face a different set of 

challenges than those studying fungus diversity. Vogt and others (1992) provide an 

excellent review of factors affecting basidiomycete sporocarp production in forest 

ecosystems with an emphasis on sampling challenges. This section emphasizes 

practical field procedures for forest managers to monitor several commercially valuable 

edible mushrooms.

Selection of study sites depends on the goals of the study. If investigators want 

unbiased estimates of mushroom production in a given habitat type, then sampling 

locations must be selected randomly or systematically; that is, without prior knowledge 

of mushroom occurrence or abundance. These studies can be expensive, because even 

if chosen sites have appropriate habitat, some sites may not have populations of the 

selected mushroom. More sites therefore must be chosen, vi sited, and sampled to 

obtain adequate estimates. If unbiased estimates of mushroom production across 

landscapes (with a variety of habitats) are desired, then stratified sampling techniques, 

based on current knowledge of habitat requirements, can improve efficiency.

Known fruiting sites should be selected when investigators plan to apply experimental 

treatments, study the biology and ecology of a given mushroom, or measure productivity 

in areas of particular interest to managers or harvesters. The biased selection of these 

sites prevents valid extrapolation of productivity estimates across broader landscapes.

Careful site selection becomes particularly important when research addresses commercially valuable mushrooms. Sites must be secure from trespass and unauthorized
51

collection of sporocarps but also readily accessible to field crews. Field personnel often are 

aware of obscure areas, or areas located on roads having lockable gates to limit access.

Unauthorized harvesting is particularly difficult to prevent on study sites having highly 

valuable mushrooms such as matsutakes. Harvesters know most fruiting locations and often 

consider patches as "theirs" because they have harvested them for many years. Ideally, 

investigators can convince local harvesters to participate in the study and thus avoid conflicts 

when these sites are selected for research.

Research site security may be enhanced in several other ways. Educating the public about 

research activities and goals is the most effective way to minimize intrusion and damage. 

Examples include providing handouts and verbal explanations when individuals obtain 

permits, showing educational videos, and publishing articles in the local press. "No 

Mushroom Harvest" signs are essential to inform the public that collection is not allowed in 

the study area. Because these signs often attract unscrupulous harvesters, they should be 

posted within the site and not be visible from a road. Signs should be large, brightly colored, 

and posted low, because mushroom pickers usually have their attention focused on the 

ground. Illustrations of the most commonly collected mushroom in the area, overlain with the 

circle and slash symbol, effectively communicate the message to non-English-speaking 

harvesters. When pickers obtain permits, they should be shown examples of the signs and 

instructed to avoid harvesting in posted areas.

Frequent visits to research sites by field crews is another effective means of security. Law 

enforcement officers can visit the site regularly and cite or ticket individuals who are picking 

illegally. Researchers and officers should greet harvesters politely, explain the purpose of the 

study and the restrictions, ask them to avoid the area, and solicit their help in informing 

others. When mushrooms are harvested as part of the study, investigators may choose to 

cooperate with previous harvesters of the site; the harvesters obtain exclusive access and 

can sell mushrooms found on the site in exchange for their efforts harvesting the site and 

providing the data to researchers. If the mushrooms are regularly picked, or marked in a 

manner that destroys their commercial value, unauthorized harvesters will find the site 

discouraging.

Studies of edible fungi usually are confined to their fruiting season. The start and duration of 

the season typically depends on weather, and thus is somewhat unpredictable. 

Autumn-fruiting mushrooms usually begin to appear soon after the onset of autumn rains 

and continue until a hard frost. Abundance of fruiting also differs considerably from year to 

year. Supervisors must be flexible in arranging personnel to implement mushroom studies. 

Unlike studies of fungus diversity, though, crews do not require extensive training in 

mushroom identification. Most commercially harvested species are easily recognized.

When volunteers help investigators with field sampling, it is important to recognize their 

attitudes toward and interest in mushroom harvesting. Recreational pickers may have 

different opinions than commercial harvesters, and both should be respected. Participation in 

conducting objective, scientific research is an opportunity for communication among groups 

with various interests. Volunteers should be rewarded for their efforts

Field Crews
whenever possible. Reimbursing their expenses and allowing volunteers to keep collected 

mushrooms after recording measurements are two possible rewards. Volunteers also may 

be included in the planning, review, and modification of studies. Signifi cant contributions 

on their part should be publicly acknowledged.

The life history of mushrooms is another relevant consideration in designing studies. Most 

important wild, commercial species are ectomycorrhizal, and this symbiotic relation with 

forest trees currently makes artificial inoculation and cultivation expensive, 

time-consuming, and difficult. Truffle plantations in Europe and elsewhere are the best 

current examples of successfully producing edible sporocarps of an ectomycorrhiza 

species through artificial propagation. The high value of culinary truffles makes seedling 

inoculation and intensive plantation management cost-effective. Research on cultivating 

other ectomycorrhizal species is being conducted in several countries. The Japanese have 

developed techniques for enhancing production of native matsutake colonies and 

spreading the fungus to new forest sites (Kawai and Ogawa 1981, Ogawa 1982, Tominaga 

1978), and pines in New Zealand are being inoculated with matsutake and bolete species. 

Efforts to cultivate Boletus species in France, Lactarius sangifluus in Spain, and 

Cantharellus cibarius in Sweden illustrate the interest in bringing other mycorrhizai species 

into cultivation in spite of the difficulties. Plantation management may eventually become 

profitable for cultivation of two Pacific Northwest truffles (Tuber gibbosum and Leucangium 

(Picoa) carthusiana) and the American matsutake (Tricholoma magnivelare), but 

harvesting in the wild likely will continue. Some commercial harvest of the less abundant 

saprobic species (for example, Pleurotus ostreatus, Hericium abietis, and Sparassis 

crispa) does occur in the wild, but many prized edible saprobes, such as Pleurotus and 

Agaricus species, are relatively easy to grow and fruit in culture.

Ectomycorrhizal species persist for long periods on sites where their tree hosts remain 

healthy. Study 8 illustrates this point for chanterelles. Markers used to designate sporocarp 

positions were color coded by year of sampling. After several years, the different colors 

were tightly clustered, suggesting that fruiting often occurs in the same location. Similarly, 

Japanese studies of matsutake fruiting demonstrate that sporocarps develop on the 

leading edge of slowly moving mycelial colonies called shiros (Ogawa 1975, Tominaga 

1971). Repeated fruiting in nearly the same location from year to year allows researchers 

to map clusters of sporocarps. Experimental treatments (such as picking versus no 

picking) can be applied to these clusters in subsequent years. Studies 8 and 11 illustrate 

selection of sporocarp clusters for application of experimental treatments. Persistent 

patches of mushrooms also provide the opportunity to investigate annual sporocarp 

formation and productivity in response to site conditions, microclimate, mycelial colony 

characteristics, and mycorrhiza abundance.

In the Pacific Northwest and intermountain West, morels represent yet another life history 

group of edible mushrooms. Massive, episodic fruitings of certain morel species often 

occur in response to events such as logging, fire, insect infestations, and ground 

disturbance. These large fruitings subside dramatically over the next several years after 

the event, although the magnitude and rate of decline are poorly documented. Persistent 

fruiting at low levels does occur without disturbance, but large, disturbance-related crops 

are most cost-effective for commercial harvesting in this region. The episodic nature of 

fruiting places constraints on the location and timing of studies. The unique life history of 

morels and related research challenges are discussed in detail in study 7.

Life Histories

52
The term edible mushroom inventories refers to either surveys of occurrence or estimates of sporocarp production (counts or weights) per unit area. We use the term 

"monitoring" when those inventories are repeated to detect trends. Monitoring also can 

be used more broadly when it refers to tracking or understanding the health or viability 

of a resource, as illustrated below in this chapter. Baseline surveys of occurrence and 

estimates of annual variation in productivity are needed to determine if commercial 

harvesting diminishes subsequent fruiting or interferes with the reproduction of these 

fungi over extended periods of time (that is, decades or several timber rotations). 

Habitats change as forests mature and experience replacement events such as logging 

or fire, hence baseline inventories must be tied to habitat types if we are to measure 

and predict long-term trends in occurrence and production across landscapes. All 

renewable resources have inherent limits to sustainable harvesting, and we are just 

beginning to theorize about the functional limitations for forest fungi. Creative experiments can test many of our hypotheses, but final verification of sustainable harvesting 

will result only from careful long-term monitoring.

Investigators must distinguish between total biological production and commercial 

production when planning inventories. Commercial harvesters use efficient search 

patterns to obtain the most valuable mushrooms with the least effort; mushrooms too 

small, damaged, or old are usually not collected. Mushrooms not commercially harvested may be important as food for wildlife or for reproducing the species via spore 

dispersal. Clear objectives regarding the type of production information needed will 

determine monitoring methods. For measuring commercial production, managers 

could give commercial harvesters exclusive access to a defined area and weigh all the 

mushrooms they collect by commercial grade. If an estimate of total production and 

animal use of the resource is desired, then thorough sampling designs and searching 

techniques must be used.

Sample plot shape, size, number, and location are important considerations for efficient 

and accurate mushroom inventories because edible fungi tend to fruit in several 

clustered arrangements (Vogt and others 1992). Plots are typically shaped as circles, 

squares, or strips. Strip plots, commonly called transects, are actually elongated 

rectangular plots located along a transect. Walking along strip plots is quicker than 

stopping repeatedly for sampling numerous, small, circular or square plots. The 

perimeters of narrow strip plots are easily measured from a single transect, whereas 

determining the perimeter of a large circular or square plot is difficult in brushy areas 

unless borders are permanently marked. For a given sample area and number of plots, 

strip plots may be more likely to intersect clustered sporocarps and provide a representative sample, but this assumption needs testing. "Adaptive cluster sampling" (Thompson 1992) is a theoretically efficient sampling method for populations that have clustered individuals, but its practicality for mushroom sampling under field conditions has 

not yet been tested.

Field personnel walking along the center of a strip plot are more likely to detect mushrooms near the center than on the edges. This error (lower probability of detection near 

the edges) becomes worse with wider strips (Thompson 1992) and brushier sites. 

When a strip plot is sampled by two individuals walking along either side, the probability 

of detection greatly increases because partially hidden sporocarps may be observed

53

Sampling Designs

Total Versus

Commercial Production

Inventories and Monitoring
from either of two angles. If strip plots are sufficiently narrow (2 meters [6.6 ft.] wide or 

less), field personnel can sample from the sides without stepping into the plots, thus 

avoiding soil disturbance or compaction within the plot (Mehus 1986, Ohenoja and 

Metsänheimo 1982, Ruhling and others 1984). Walking repeatedly along the 

immediate edge of a narrow strip plot does, however, tend to create highly impacted 

trails that can be erosive on steep slopes. Soil disturbance in these trails may impact 

mycorrhizal formation or mycelial growth and, consequently, alter fruiting patterns in 

the immediately adjacent plots. Strip plots 5 to 8 meters (16.4 to 26 ft.) wide allow 

sampling personnel to walk on the plot in a pattern that changes with each visit, 

thereby dispersing trampling impacts.

Strip plot widths also must correspond to required sample area. The total sample area 

needed for adequate productivity estimates is directly related to sporocarp abundance 

and distribution patterns within a site. Abundance is an especially difficult consideration 

because it changes from year to year. A sample area large enough to produce a 

reasonable sample during a year with light fruiting, may yield an overwhelming and 

unnecessary workload in a year with heavy fruiting. Investigators must either select 

sample areas that are workable at both extremes or subsample in years of heavy 

production. Approximations of adequate sample areas for various edible mushroom 

species are provided in the ongoing studies described here. Unfortunately, even with 

sample areas of 2,500-10,000 square meters (3,000 to 12,000 yd2), production 

estimates for a single mushroom species are frequently imprecise (Pilz and 

Amaranthus, unpublished data); that is, the estimates have broad confidence intervals 

(the range of values that have a given statistical probability of including the true value). 

Two-meter wide (6.6-ft. wide) strip plots would need to be kilometers in length to yield 

such large sample areas. A reasonable number of circular or square plots covering this 

area would be so large that personnel would experience difficulty determining where 

they had already searched unless the plot were elaborately subdivided. Investigators 

must balance the shape and arrangement of the plots with how much walking is 

practical, ease of sporocarp observation, site brushiness, and potential for soil 

compaction or erosion from repeated visits.

Investigators also must decide whether to sample mushroom production at a given site 

or within a given habitat type. If characterizing mushroom production at a given site 

(say a logging unit) is desired, systematically located strip plots are easy to establish 

because beginning and end points are typically located at the edge of the site 

(commonly a road) and follow parallel compass bearings. All microhabitats, whether 

suitable for the mushroom of interest or not (that is, logs, streams, rocks, nonectomycorrhizal host vegetation, and so forth), are included in the sample so that 

per-unit-area production estimates characterize the site as a whole. If the investigator 

wants an estimate of mushroom productivity in a given habitat type, then either 

production estimates must be adjusted downwards by the percentage of inappropriate 

habitat that falls within the sample plots or sample areas must be selected that exclude 

obviously inappropriate habitat. For instance, a manager wishing to estimate 

chanterelle productivity in local Douglas-fir stands would avoid sampling alder thickets 

along streams (or proportionately adjust production estimates) because alder does not 

form mycorrhizae with chanterelles. Randomly located plots provide greater assurance 

of unbiased

54
estimates than systematically located plots, but may require a little more effort to locate, 

establish, and sample because, to relocate them, they need to be better marked and 

documented than strip plots starting from the edge of a road. A distance or orientation 

criterion also must be used to ensure that randomly located strip plots do not overlap.

The scale of the inventory is another important consideration in selecting sampling designs. 

For instance, strip plots may be practical for sampling mushroom populations in a forest 

stand or small watershed, but different approaches may prove more useful for 

characterizing populations over landscapes or regions. For example, many land 

management organizations have established forest inventory plots (various sizes and 

shapes) across their landscapes. These inventory plots provide the opportunity to sample 

mushrooms at sites where the vegetation and environment have already been fully 

described, thus allowing cost-effective correlations of productivity with habitat factors.

The verb "to mushroom" derives from observations that sporocarps often grow and 

mature rapidly. To estimate edible mushroom production, we must decide when and how 

they will be measured. In essence, we are taking snapshots in time of their development.

To estimate total biological productivity of an undisturbed site across a season, one would 

mark and track individual mushrooms, measuring or weighing them only when they reach 

maximum size (assuming they did not get picked by humans or eaten by animals first). 

This procedure would be very labor intensive and for many purposes, unnecessary. 

Individual sporocarps of chanterelles, for example, persist 2 to 8 weeks in the field, 

allowing sampling intervals of a week or longer before mature sporocarps are lost to 

decay. Mushrooms under a certain size can be left for sampling during the next visit, 

allowing them to mature. Sampling interval and minimum size criteria must be clearly 

explained to properly interpret the resulting data.

In areas of intensive commercial collection, some harvesters visit sites daily and harvest 

a mushroom only when it reaches optimum commercial value, as defined by specific size 

and maturity criteria. Cooperating with collectors using this method provides a very 

accurate measure of commercial mushroom production at a site.

The simplest way to determine mushroom biomass is to pick and weigh them. Unfortunately, 

no one has conclusively demonstrated whether picking influences the size, number, or 

biomass of subsequent sporocarps, either that season or in following years. Study 8 

suggests no short-term effects of harvest on subsequent chanterelle production, but 

carefully replicated comparisons are needed for other mushroom species. Studies 9 and 11 

also address this issue, as will the planned morel inventories mentioned in study 7.

Mushrooms readily absorb rainfall and dry quickly, which causes rapid changes in 

mushroom moisture content. When accurate fresh weights are desired, mushrooms should 

be protected against excessive drying during transport from the field to the weighing facility. 

A picnic cooler works well to transport mushrooms. Plastic field collection bags retain 

moisture too well if the study includes measurements of commercial grades. Fresh 

mushrooms transpire ("sweat') moisture that condenses inside the

55

Sampling Methods and 

Units of Measure
bag; they then get wet and rapidly become slimy. Paper bags breath adequately but often 

tear when wet. Small waxed bags work well for individual mushroom specimens but are too 

small for the larger collections typical of plot samples. Cloth bags work well because they 

breath and do not tear when wet. Plastic buckets used by commercial collectors protect 

mushrooms well in the field but can be cumbersome, especially if multiple buckets are used 

to collect a separate sample for each strip plot. Mushrooms from each strip plot can be 

placed in separate cloth bags that are then carried in a single bucket for field protection. 

Regardless of the collection method, mushrooms must be weighed promptly for accurate 

fresh weights.

Any inventory of total production should rely on dry weights for comparisons among sites 

and sampling periods, because mushroom moisture content will change with differences 

or changes in the weather. If it is impractical to dry all sampled mushrooms, investigators 

can weigh subsamples, calculate a dry-to-wet weight ratio, and use this ratio to estimate

total dry biomass from the total fresh weight.

Estimating the weight of non-harvested mushrooms requires different procedures. Size and 

dry weight measurements of a representative sample of picked mushrooms can be used to 

develop regression equations that estimate weight of nonpicked mushrooms from 

measurements of their size. Various size attributes can be used: maximum, minimum, or 

average cap diameters (all species); cap height (morels); stem diameter at the annulus 

(matsutakes); or stem diameter where it meets the hymenium (chanterelles). Bending and 

kneeling to measure stem diameter in the field is physically difficult, and measuring total 

height or stem length is problematic if part of the stem or its base is imbedded in duff or soil. 

Equations currently are being developed to determine best size criteria, or combination of 

criteria, for estimating the weight of each species. See studies 7, 9, 10, and 11 for examples, 

and Vogt and others (1992: 569) for a discussion of difficulties with this method.

When sample mushrooms are not harvested, field crews must know which mushrooms were 

measured during the previous sampling interval to avoid (or keep track of) repeat sampling. 

Mushrooms can be marked in several ways: with permanent felt-tip markers, paint, nail 

polish, food coloring, colored toothpicks, or small bulletin board pins with colored heads. 

Each method has drawbacks. Chemicals in the markers and paint may be toxic and 

influence sporocarp growth. Food coloring is nontoxic and less likely to affect mushrooms but 

may not persist in rain. Round toothpicks (the colored party variety) tend to crack open the 

caps of small sporocarps, and small pins may be lost on the site (to the potential detriment of 

small mammals) after mushrooms have decayed. The thin, flat variety of wooden toothpick is 

unlikely to split mushroom caps and may be painted if greater visibility is needed. Markers 

placed next to (rather than in) measured mushrooms should always be placed on the same 

side (compass orientation), so they are not mistakenly associated with mushrooms that fruit 

subsequently.

Some mushroom collectors report that mushroom harvesting influences the size or 

abundance of mushrooms that fruit later in the season or in following years. Confirming or 

refuting these anecdotes requires a statistical comparison of harvest and no-harvest 

treatments; sporocarps are collected and weighed on harvest plots, and counted and 

measured for size and weight regressions on control plots. Three years of baseline 

productivity data were collected from plots (selected clusters) in study 8 before harvest

Studies of Mushroom 

Harvesting Effects

56
treatments were applied. The usefulness of applying harvest treatments with only one year 

of baseline data will be assessed for matsutake mushrooms in study 11.

Inventory strip plots can be used for harvest impact comparisons, but if harvest and noharvest plots are adjacent, comparisons could be confounded by the possibility that 

sporocarps from both plots may be connected by underground mycelia that share responses 

to harvesting disturbance. Some mushroom harvesting impacts may result from destructive 

searching techniques used by inexperienced harvesters, such as raking forest duff layers to 

find immature sporocarps. Examining the impacts of searching techniques is most readily 

studied in a replicated experimental design using analysis of variance (ANOVA) to compare 

treatments and possible covariation with environmental factors like soil type (study 11 is an 

example).

Individual sporocarps do not recur, so they are not appropriate experimental units for 

measuring the impact of harvesting treatments. Insofar as clusters of mushrooms can be 

assumed to represent the fruiting of distinct mycelial colonies, they are more appropriate 

experimental units for measuring the impact of sporocarp harvesting on the fruiting behavior 

of a fungus individual. Cluster productivity can be measured by numbers of sporocarps, and 

weight can be measured or estimated. Comparisons should be based on the relative 

increase or decrease in productivity of treated clusters compared to control clusters, 

because all clusters will experience annual background variation in fruiting levels related to 

weather or physiological cycles.

Before application of experimental treatments, clusters of sporocarps must be mapped and 

delineated. Clusters should contain fairly uniform numbers, biomass, and spacing of 

sporocarps, so that treatments are applied to similar experimental units. Anticipated 

covariance also should be kept to a minimum to obtain maximum sensitivity of statistical 

comparisons. The most likely source of covariance is a physiologically shared response to 

different treatments by clusters fruiting from a single mycelial colony (individual). Similarly, 

genetically distinct mycelia of ectomycorrhizal species may share the same host tree, and 

therefore share common physiological responses to treatments. Clusters receiving 

experimental treatments should be sufficiently distant from each other to minimize the 

chance of shared mycelia or hosts. Molecular techniques of genetic analyses will be useful 

for determining the normal extent of mycelial colonies for different species. This will allow 

researchers to define adequate separation of clusters without using unnecessarily large

distances.

Once clusters are defined, experimental treatments are randomly assigned to them. 

Replicating experimental treatments requires use of either multiple sites or blocking 

clusters within a site according to similar microenvironmental factors, or both.

Managers value prompt results to support their decisions; therefore, investigations supported 

or conducted by land management agencies must carefully consider how many years of 

baseline data provide adequate precision for their comparisons. Mapping sporocarp 

locations and abundance for several years before treatment application likely would improve 

cluster definitions, and several years of baseline data would test the assumption that control 

and treatment clusters exhibit similar annual variation in production if they are not treated. 

On the other hand, cluster definition may be adequate after only one year of mapping, and 

sufficient replication of randomly assigned

57
treatments should compensate for variation among clusters in the annual fluctuations of 

productivity. Study 11 illustrates these procedures and considerations.

Forest thinning or clearcutting, soil disturbance, fire, fertilization, cattle grazing, and allowing 

forest stands to age naturally all potentially influence edible mushroom produc tivity. Studies 

of forest management effects will allow managers to predict trends in edible mushroom 

production as these activities change forest landscapes. Studies can be located where 

management activities have already occurred (retrospective) or where they are planned 

(prospective).

Retrospective studies compare inventories in areas affected by a particular land 

management activity with inventories in non-affected areas (controls). Retrospective 

comparisons require more careful and extensive replication of inventoried sites than 

prospective studies because variation in the presence and abundance of mushrooms on 

the inventoried sites prior to the management activity is unknown.

Prospective studies typically employ baseline inventories of mushroom production to 

enhance statistical comparisons and simplify interpretation. Although fewer sites may be 

needed than with retrospective comparisons, replication of the experimental treatments still 

require multiple sites because management activities are typically applied to entire forest 

stands.

Stand treatments can be compared by sampling sporocarp production on strip plots, but the 

power of ANOVA comparisons derives from the degrees of freedom (number of treatment 

replicates minus one), rather than the number of plots within each treatment. Therefore, plots 

need not be as large, long, or numerous within each treatment location as is needed to obtain 

narrow confidence intervals for productivity estimates on a single site. Indeed, one large plot 

in each replicated treatment (stand or site) would be adequate if the investigator is not 

concerned about assigning confidence intervals to an estimate of productivity at individual 

treatment locations.

Experiments on the scale of forest stands are expensive and rarely justified simply to 

examine effects on mushroom production. Opportunities exist, however, to cooperate with 

integrated research projects examining the influence of land management activi ties on 

various ecosystem components and processes. Cooperating with integrated research 

restricts mushroom investigators to the overall design and objectives of the project, and field 

activities must be carefully coordinated. The mushroom portion of the study becomes less 

expensive, however, and considerable information on site conditions is available. Studies 9 

and 12 illustrate edible mushroom monitoring conducted as a component of an integrated 

research project.

Interpretation of inventory data or experimental results will be enhanced by an improved understanding of mushroom biology and ecology. A short list of topics and 

relevant questions worthy of further investigation follows. Study 13 illustrates an 

approach for investigating some of these topics.

Environment—How do micrometeorological factors (for example, soil temperature and 

moisture content) influence the onset and progress of sporocarp development? Are patterns 

of annual variation in sporocarp abundance or size cyclical in nature? If so, what factors 

regulate the patterns? How uniform are fruiting patterns among populations located in 

different forest stands, watersheds, landscapes or regions?

Studies of Forest

Management Effects

Studies of Biology and

Ecology

58
Mycelial colonies—What factors influence establishment, growth and decline of the fungal 

mycelium for a given species? How deep, extensive, and dense is the mycelial colony that 

produces sporocarps? How quickly does it spread through the soil? Does a fungus reach its 

maximum vigor or competitiveness in stands of a certain age? What are the preferred host trees 

for mycorrhizal species? How does the fungus interact with other fungi or soil organisms?

Reproduction—How does the species reproduce? How important is spore dissemination to 

reproduction, and does commercial picking significantly impact spore dispersal? Are episodic 

disturbance events necessary for reproduction (for example, fires for morels)? Following a 

stand-replacement event such as wildfire or logging, do fungi colonize a new forest through 

resting propagules or persistent mycelia in the soil, by maintaining mycorrhizae on rapidly 

sprouting brush species, by spores from adjacent forest, or some combination of these?

Genetics—Do colonies consist of genetically distinct, dikaryotic (two different haploid nuclei 

per cell) individuals? How commonly, and in which species, do monokaryotic (haploid) spores 

anastomose (fuse) with existing hyphae to produce heterokaryotic mycelia with more than two 

genetically distinct nuclei per cell (Rayner 1991)? How genetically diverse is the species at 

different scales (for example, within stands, watersheds, regions, or throughout its range)? Are 

there locally adapted endemic populations that may need protection?

Although few of these questions are easily answered, we must address them if managers are to 

regulate commercial mushroom harvests with confidence about long-range impacts. Answering 

these questions requires creative investigative methods that employ detailed descriptions, 

long-term correlations of fungus physiology with site conditions, and innovative field and 

laboratory experiments. Field research sites selected, secured, and mapped for harvesting 

impact or land management studies are logical locations to conduct detailed, long-term research.

Amaranthus, M.; Trappe, J.M.; Bednar, L.; Arthur, D. 1994. Hypogeous fungal production in 

mature Douglas -fir forest fragments and surrounding plantations and its relation to coarse 

woody debris and animal mycophagy. Canadian Journal of Forest Research. 24: 2157-2165.

Arnolds, E. 1988. The changing macromycete flora in the Netherlands. Transactions of the 

British Mycological Society. 90: 391-406.

Arnolds, E. 1991. Decline of ectomycorrhizal fungi in Europe. Agriculture, Ecosystems, and 

Environment. 35: 209-244.

Chen, P.Y.S.; Novy, C.; Rogers, K. [and others]. 1993. In: Thomas M.G.; Schumann, D.R., 

eds. Income opportunities in special forest products: self-help suggestions for rural 

entrepreneurs. Agric. Info. Bull. 666. [Place of publication unknown]: U.S. Department of 

Agriculture, Forest Service. Chapter 11.

Danell, E. 1994. Cantharellus cibarius: mycorrhiza formation and ecology. Uppsala, Sweden; 

Acta Universitatis Upsaliensis. 58 p. Ph.D. dissertation.

de Geus, N. 1995. Botanical forest products in British Columbia: an overview. Victoria, BC; 

Integrated Resources Policy Branch, British Columbia Ministry of Forests. 51 p.

59

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Jansen, E.; van Dobben, H.F. 1987. Is decline of Cantharellus cibarius in the Netherlands 

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65-83.

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MacKenzie, J.J.; EI-Ashry, M.T. 1990. Air pollution: toll on forests and crops. New 

Haven, CT Yale University Press.

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aspects of wild edible mushrooms in the forests of the Pacific Northwest: a preface to 

managing commercial harvest. Gen. Tech. Rep. PNW-GTR-309. Portland, OR; U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Research Station.

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Japan;: Government Forest Experiment Station.

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and Consultation Office, Forest Service Research Station. 158 p.

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subarctic Finnish Lapland. In: Laursen, G.A.; Ammirati, J.F, eds. Arctic and alpine mycology. 

Seattle: University of Washington Press: 371-389.

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forest decline associated with anthropogenic pollution. In: Schulze, E.D.; Lange O.L.; Oren, R., 

eds. Forest decline and air pollution: a study of spruce (Picea abies) on acid soils. Berlin, 

Germany; Springer-Verlag: 23-46.

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34-36.

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Conference Presentations on Productivity and 

Sustainable Harvest of Wild Mushrooms

Study 7: Morel Life Histories–Beginning to Address 

the Unknowns With a Case Study in the Fremont 

National Forest Near Lakeview, Oregon

Nancy S. Weber, David Pilz, and Carol Carter 1 2

In the forested regions of the North Temperate Zone, true morels (Morchella Pers. : 

Fr.) are the premier spring wild mushroom collected for personal and commercial use 

(Weber 1995). True morels are easily distinguished from other wild mushrooms, but 

identifying a given collection to species is often frustrating. The modern history of 

scientific nomenclature for mushrooms begins with the works of the Swedish scientist 

Linnaeus. Linnaeus (1753) placed what is now called the common, white, or yellow 

morel (Morchella esculenta (L. : Fr.) Pers.) in the genus Phallus as P. esculentus L. 

Since the time of Linnaeus, several dozen species and subspecific taxa in Morchella 

have been described and named. Korf's (1973) estimate that there are probably only 

three good species may be low, but an estimate of a dozen good species may be high. 

No modern synthesis of the genus giving probable synonymies has appeared. Several 

studies are underway that may yield insight as to how many species of true morels 

merit recognition.

1Nancy Weber is with the Department of Forest Science, Oregon State University, Corvallis, OR 

97331; David Pilz is with the U.S. Department of Agriculture, Forest Service, Pacific Northwest 

Research Station, Corvallis, OR 97331; and Carol Carter is with the Biology Department, Portland 

State University, Portland, OR 97207. Funds for Weber's work provided in part by the National Science 

Foundation through grants DEB 9007186 and DEB 9400545.

2Cooperating was Betty Charon, USDA Forest Service, Fremont National Forest, Lakeview Ranger 

District, Lakeview, OR 97630.

Context

62
For this discussion, we divide the true morels into four informal groups: the half-free morel 

(M. semilibera DC : Fr.); the common, white, or yellow morel(s) (M. esculenta and related 

taxa); the black morel(s) (M. conica Pk., M. elata Fr. : Fr., and allied taxa); and the fire 

morel(s) (M. esculenta var. atrotomentosa Moser, and M. conica var. nigripes Moser). All 

four groups are represented in western North America.

The life cycle and life style (mode of nutrition) of true morels differ from those of the matsutake 

and the golden chanterelle, both of which are believed to be obligately mycorrhizal and are not 

known to form either sclerotia or conidial states (anamorphs). In contrast, true morels are 

saprobic or at most facultatively mycorrhizal. They regularly form sclerotia (dense masses of 

tissue) and conidial states as part of their life cycle (Matrouchot 1892; Molliard 1904a, 1904b, 

1905; Ower 1982; Stamets 1993). Furthermore, Ower (1982), working with isolates from 

California, and Ower and others (1986) established that M. esculenta can be cultivated from 

spores and complete its entire life cycle as a saprobe. Ower (1982) worked with tissue 

cultures and cultures started from ascospores of a single specimen. In Europe, Buscot (1989, 

1992, 1993a, 1993b, 1994), Buscot and Kottke (1990), and Buscot and Roux (1987) have 

described various types of associations among mycelia of M. rotunda (Pers.) Boud. (same 

group as M. esculenta), M. elata, and M. semilibera and roots of Picea abies. Buscot (1994) 

postulates that morels may be involved in complex ectomycorrhizal relations under some 

conditions. Successful attempts at pure culture synthesis of morel mycelium and roots of 

possible hosts have not been reported.

Many questions remain about the mating types and nuclear behavior in morel life cycles. The 

scheme presented in figure 1 is undoubtedly oversimplified, but will serve as an introduction 

to the apparent complexity of the morel life cycle. We have drawn on the life cycle presented 

by Volk and Leonard (1990) and other publications in developing figure 1.

The least complex possible nuclear cycle may involve two mating types (n, n'). Each 

ascospore and the cells of its products (definitely the primary mycelium and sclerotia and 

possibly conidiospores and sporocarps if they are formed) contain nuclei of only one mating 

type (n or n'). For the cycle to be completed, a secondary mycelium (both types of nuclei 

present in each cell) is formed. The cells in the secondary mycelium may contain both types of 

nuclei, singly or in pairs (dikaryons) (n, n', n+n'; Volk and Leonard 1990). All the products of 

the secondary mycelium, except possibly the conidiospores, are likely to share this pattern. 

We have seen no reports on the nuclear condition of the conidiospores; in many other 

members of the Ascomycotina, uninucleate and binucleate conidiospores may be formed 

which results in several possible types of conidiospores (for example, n, n', n and n, Wand n', 

n and n'). In the ascus, two nuclei of opposite mating type fuse and undergo meiosis producing 

eight haploid (n or n') ascospores. Other mating systems may occur; for example, Volk and 

Leonard (1990) interpreted Ower's (1982) work to imply that the progeny of a single spore 

might complete the cycle (noted with "?" in fig. 1).

The important lesson of this complex life cycle is that there are many potential points at which 

management decisions may impact future crops of morels. The possibility that sclerotia 

produced by the primary mycelium (haploid, monokaryotic mycelium) might

63
64
form sporocarps was inferred from Ower's (1982) work and remains an area of uncertainty. The 

role and behavior of the conidiospores also remains unresolved. The primary and secondary 

mycelia are the vegetative stages of the organism, responsible for obtaining nutrients and so 

forth; the sclerotia may function as storage organs or tide the organism over unfavorable 

conditions.

Each of the four groups of morels appears to have different ecological preferences. The 

common and half-free morels occasionally fruit abundantly in mechanically disturbed (but likely 

not burned) areas. They also may fruit regularly, if less abundantly, in relatively stable habitats 

in association with broad-leaved trees in the Rosaceae, Salicaceae, Fagaceae, and possibly 

the Ericaceae. In western North America, black morels are most abundant in coniferous 

forests, especially those attacked by insects, and in burned areas. Fire morels are the least 

well known; they may be restricted primarily to severely burned coniferous forest at moderate 

to high elevations. The black and fire morels from burned areas are the backbone of the 

commercial morel crop in western North America.

Several papers (Coombs 1994, Duchesne and Weber 1993, Miller and others 1994) contain 

information that could lead to the development of methods for predicting or enhancing the morel 

crop. Duchesne and Weber (1994) report that in May following a prescribed burn in September 

1990 in Ontario, Canada, a massive fruiting of morels developed in the burned area but not in 

the adjacent forest. Coombs (1994) describes the initial stages in an experiment where morel 

sclerotia were introduced into a burned area to see if such inoculation would increase the crop. 

Miller and others (1994) found what they identify as morel sclerotia in soils burned in the 1988 

fires in Yellowstone National Park. Perhaps some way of estimating the potential crop based on 

the density of sclerotia could be developed.

Informed management of wild morels is possible only if we know which organisms are 

involved, agree on what to call them, and understand their biology and ecology. Areas in need 

of attention include (1) defining the species and arriving at a stable set of names for them, (2) 

gathering baseline data on natural fruiting patterns for each species, with emphasis on those 

gathered in commercial quantities, and (3) confirming the life cycle and life style variations for 

at least the major species. Studies of macroscopic and microscopic changes in sporocarps as

they mature, population structure at the molecular level, and productivity over a period of years 

are just some of the topics awaiting attention.

As a result of contacts made during the conference, the authors initiated a study on morel 

fruiting patterns. The Lakeview Ranger District, Fremont National Forest, in south-central 

Oregon was chosen because of interest in the project by local staff and an abundant fruiting 

of morels in the area.

The objectives of this preliminary study included:

1. Testing selected ways of quantifying information on abundance of sporocarps per unit 

area.

2. Developing regression formulae relating sporocarp weight and size.

3. Gathering baseline estimates of productivity for use in comparing future 

fruiting levels.

4. Gathering samples for morphologic, taxonomic, and population genetics studies.

65

Objectives
66

We developed a method for setting up random strip plots to count morel sporocarps. Using 

a belt-chain and compass, we established a line 183 meters (600 ft.) long. We sampled 

morels within a band 1 meter (3.2 ft.) wide on each side of the line. All morel sporocarps 

were gathered by gently detaching the intact sporocarp from its mycelium (with a minimal 

amount of adhering debris). Sporocarps from each transect were placed in separate, 

labeled kraft bags. For each transect, sporocarps were sorted into four size categories 

approximating commercial grades. Within each grade and transect grouping, sporocarps 

were counted, weighed, and placed in a dehydrator (Trappe 1982). After drying, they were 

weighed again.

Sporocarps close to, but outside, the edge of the transect were gathered, kept in separate 

individual bags, and labeled with their position along the transect (distance and whether 

right or left of median line). Size and weight measurements of these sporocarps were used 

for the regression formulae. The next day, the sporocarps were cut in half longitudinally; 

one-half of each sporocarp was used for molecular studies of population genetics, and the 

other half was kept as a voucher sporocarp for studies of sporocarp morphology.

Data collected over a period of years will provide an estimate of population fluctuations and 

can be used in conjunction with various types of habitat manipulation to ascertain effects on 

fruiting patterns of morels. Because we observed morels to be clustered on the landscape, 

strip plots may show great variability in numbers of sporocarps encountered. Multiple strip 

plots must be sampled within a short period to provide precise estimates of site productivity. 

Genetic and morphological analyses of specimens will be used to determine variation within 

and among populations and species.

A three-person field crew is optimal. When morels are abundant, only two or three strip plots 

can be completed in a standard working day. This schedule includes travel time, taking 

notes on sporocarp morphology, and sorting, counting, weighing, and drying sporocarps as 

well as preparing samples for molecular analysis. Crews need to be trained in the survey 

technique, in identification of morels, and in techniques for recording data and processing 

sporocarps. Several crews could be trained together in a 1- to 2-day workshop, with part or 

all of one day spent in the field.

Each crew should have:

• standard safety equipment

• compass

• belt-chain (preferably calibrated in meters)

• dowel, rod, or stick cut to 1 meter in length

• supply of large (standard grocery size) and small (lunch bag size) kraft bags

• basket for carrying supplies and samples (paper bags may tear when wet)

• indelible markers

• knives, trowels, or other implements for easing sporocarps from their substrate

• cooler(s) to hold sporocarps and prevent overheating or desiccation during travel time

Methods and Rationale

Unique Considerations
In the laboratory, facilities are needed for sorting, weighing, and drying the sporocarps. Home 

food dehydrators, available in many markets for about $60-100, are recommended. Those with 

adjustable temperatures and a fan are preferred. Sporocarps to be dried are cut in half 

lengthwise, placed in a single layer on each screen, and clearly labeled. The sporocarps 

should become as crisp as a fresh potato chip in 12 to 16 continuous hours of dryer operation. 

A steady drying temperature in the range of 35 to 50 °C (about 95 to 120 °F) and good air 

circulation are recommended to prevent collapse of the sporocarps. When sporocarps are 

removed from the dryer, the dry weights are determined and each set of sporocarps is placed 

in a clean bag, labeled, and stored in an insect-proof place for further morphological study. 

During the drying process, mature morels release large quantities of spores. These spores 

may cause allergic reactions in some people, thus the dryers should be located in a 

well-ventilated area or under an exhaust fan, so that the spores will not affect workers. 

Sporocarps for molecular studies are labeled, placed in small coolers with a block of artificial 

ice, suitably packed so that the sporocarps are not damaged, and express shipped to the 

laboratory. They also may be frozen and shipped later.

Morel season in a given area and elevation usually lasts only a few weeks, although by moving 

from lower to higher elevations, or from warm to cool exposures, morels can be found over 

several months in some mountainous areas. The season starts after snow melt when rains are 

relatively regular and the soil warms; generally, nights are cool and days warm at the start of 

morel season. The season can end abruptly with the arrival of hot, dry weather. Trying to 

schedule crews for a particular time and place more than a few weeks in advance is not 

recommended. Rather than have one or two crews responsible for survey in several dispersed 

districts or forests, each organization may prefer to have a local trained crew that can be 

assigned to morel duty on a few days notice.

The principal investigators have begun an expanded and replicated study of morel 

productivity, ecology, taxonomy, and population genetics following wildfires and tree mortality 

in the mountains of northeastern Oregon. Michael Amaranthus (Pacific Northwest Research 

Station, Grants Pass, OR) is concurrently installing a case study of morel responses to site 

conditions and tree mortality in a recently burned area of southwestern Oregon.

Buscot, F. 1989. Field observations on growth and development of Morchella rotunda and 

Mitrophora semilibera in relation to forest soil temperature. Canadian Journal of Botany. 67: 

589-593.

Buscot, F. 1992. Ecological and biological strategies of morels. Cryptogamie –

Mycologie. 13: 171-179.

Buscot, F. 1993a. Mycelial differentiation of Morchella esculenta in pure culture. 

Mycological Research. 97(2): 136-140.

Buscot, F. 1993b. Synthesis of two types of association between Morchella esculenta and 

Picea abies under controlled culture conditions. Journal of Plant Physiology. 141: 12-17.

Buscot, F. 1994. Ectomycorrhizal types and endobacteria associated with ectomycorrhizas 

of Morchella elata (Fr.) Boudier with Picea abies (L.) Karst. Mycorrhiza. 4: 223-232.

Current Status

Literature Cited

67
68

Buscot, F.; Kottke, I. 1990. The association of Morchella rotunda (Pers.) Boudier with roots of Picea abies 

(L.) Karst. New Phytologist. 116: 425-430.

Buscot, F.; Roux, J. 1987. Association between living roots and ascocarps of Morchella rotunda. 

Transactions of the British Mycological Society. 89: 249-252.

Coombs, D. 1994. Come spring, this project may make a lot of sense. Mushroom, the Journal of Wild 

Mushrooming. 13(46): 12-13.

Duchesne, L.C.; Weber, M.G. 1993. High incidence of the edible morel Morchella conica in a jack pine, 

Pinus banksiana, forest following prescribed burning. Canadian Field-Naturalist. 107: 114-116.

Korf, R.P. 1973. Discomycetes and tuberales. In: Ainsworth, G.C.; Sparrow, Frederick K.; Sussman, A.S., 

eds. The fungi, an advanced treatise. Vol. IV: A taxonomic review with keys: Ascomycetes and fungi 

imperfecti. New York; Academic Press: 249-319.

Linnaeus, C. 1753. Species plantarum. Holmiae. [Place of publication unknown]: [Publisher 

unknown]. 1,200 p.

Matruchot, L. 1892. Recherches sur le développement de quelques mucédinées. Paris: [Publisher 

unknown].

Miller, S.L.; Torres, P.; McClean, T.M. 1994. Persistence of basidiospores and sclerotia of 

ectomycorrhizal fungi and Morchella in soil. Mycologia. 86: 89-95.

Molliard, M. 1904a. Forme conidienne et sclérotes de Morchella esculenta Pers. Revue Générale de 

Botanique. 16: 209-218.

Molliard, M. 1904b. Mycélium et forme conidienne de la morille. Comptes Rendus Hebdomadaires des 

Séances de I'Academie des Sciences. 138: 516-517.

Molliard, M.1905. Production expérimentale de I'apareille ascosporé de la morille. Comptes Rendus 

Hebdomadaires des Séances de I'Academie des Sciences. 140: 1,146-1,148.

Ower, R. 1982. Notes on the development of the morel ascocarp: Morchella esculenta. Mycologia. 74: 

142-144.

Ower, R.; Mills, G.L.; Malachowski, J.A.; inventors, Neogen Corp., assignee. 1986. Cultivation of 

Morchella. U.S. patent 4,594,809. June 17. 7 p. Int. CI.4A01G 1/04.

Stamets, P. 1993. Growing gourmet and medicinal mushrooms. Berkeley, CA: Ten Speed Press. 552 

p.

Trappe, J.M. 1982. Alternative methods for drying fungi and controlling insects in herbaria. 

Mycologia. 74:1,014-1,015.

Volk, T.J.; Leonard, T.J. 1990. Cytology of the life-cycle of Morchella. Mycological Research. 94: 

399-406.

Weber, N.S. 1995. A morel hunter's companion. Lansing, MI: Two Peninsula Press. 209 p.
69

Study 8: Oregon Cantharellus Study Project 1986-96

Lorelei Norvell, Judy Roger, Janet Lindgren and Frank Kopecky 1 2

During an economic recession in the 1970s, many unemployed workers discovered that edible 

wild mushrooms could be harvested and profitably sold for export to Europe and Japan. 

Unfortunately the resulting increase in wild mushroom harvesting coincided with several drought 

years. Edible species became increasingly difficult to find, and recreational mushroom pickers 

began to fear that overpicking would lead to a disappearance of many species. They pointed to a 

severe decline in many popular edibles in Europe where fungi have been picked for centuries 

(Jansen and others 1985).

The perceived decrease in yellow chanterelles (Cantherellus cibarius) provoked the greatest 

concern. Commercial harvesters believed that picking the sporocarps did not endanger the 

organism, but no scientific evidence existed to support this belief. Members of the Oregon 

Mycological Society decided to conduct a pioneer 10-year study to investigate the impact of 

intensive chanterelle harvest on future chanterelle productivity.

The Oregon Cantharellus Study Project began in 1986 in cooperation with the U.S. 

Department of Agriculture, Forest Service, and the City of Portland. An unfunded study, all 

materials and labor have been donated by over 60 volunteers.

The objectives were to:

1. Determine the effects of long-term, intensive, chanterelle harvesting on subsequent fruiting.

2. Assess associated fungus and plant diversity on the chanterelle site through biweekly 

inventory of all epigeous fungi (excluding lichens) and semiannual inventory of vascular and

nonvascular plants.

The study is in a 100-year-old Tsuga heterophylla and Pseudotsuga menziesii forest within the 

buffer zone of the City of Portland's Bull Run Watershed, Mount Hood National Forest (Corbett 

and Zig Zag Ranger Districts), Oregon.

In 1986, the research team established 10 separate study plots (ranging from 16 to 64 square 

meters [172 to 690 ft.2) around clusters of fruiting chanterelles; the intent was to encompass one 

chanterelle clone per plot. Before harvest treatments were applied, workers mapped and 

measured chanterelles for 3 years to acquire baseline data. In 1989, each plot (subdivided into 

4-meter-square [43 ft.2] subplots for mapping purposes) received one of three treatment 

designations: (1) control (no removal of chanterelles), (2) pull-harvest (chanterelles pulled from 

ground), or (3) cut-harvest (chanterelles

1Lorelei Norvell is with the Department of Botany, University of Washington, Seattle, WA 98195; and Judy Roger, Janet 

Lindgren, and Frank Kopecky are with the Oregon Mycological Society, Portland, OR. Frank Kopecky served as 

coordinator, 1985-87, Janet Lindgren as instigator, Lorelei Norvell as project designer and coordinator, 1988-91, and Judy 

Roger as coordinator, 1992 to present.

2Cooperators were Dick Hardman, Rex Holloway, Molly Sullivan, Kathleen Walker, and Todd Parker; Corbett and Zig Zag 

Ranger Districts, Mount Hood National Forest; and Jim Robbins, City of Portland Water District.

Context

Objectives

Methods and 

Rationale
removed by cutting at ground level). All treatments were replicated in three blocks (one block 

has two small control plots).

Plants and other mushrooms are inventoried in all plots. Tree age will be determined from 

growth ring increment cores and soil will be analyzed at the conclusion of the study to provide 

additional ecological information. Daily temperature and precipitation data are provided by 

the Bull Run Watershed Headwork's weather station 5 kilometers (3.1 mi.) away.

Three to four volunteer researchers visit the site every 2 weeks from early July until the 

season is ended by snow in late November to early December. In no-harvest control plots, 

researchers place color-coded plastic pickup sticks with numbered flags next to each new 

chanterelle and map them by triangulation. Coordinates are obtained from metric tapes 

secured to dowel rods inserted into plastic pipes driven into the ground at all subplot corners. 

Workers determine cap diameter, stem diameter, and height of each chanterelle and report 

their measurements to another individual who records them. Measurements are repeated at 

each successive visit until the chanterelle disappears or the season is complete.

In harvest plots, all chanterelles greater than 1 centimeter (0.39 in.) in diameter are removed 

(in an attempt to duplicate "heavy" harvesting). Researchers place harvested specimens into 

(waxed) paper bags, and note the date and subplot. At completion of each day of fieldwork, 

the project coordinator measures, dries, and records biomass (dry weight in grams) of each 

chanterelle. All specimens are stored at the University of Washington fungal herbarium (WTU) 

for future molecular analysis. From 1986 to 1993, 2,893 chanterelles were tracked on the 

control and harvest plots.

During each visit, other fungus species also are inventoried on subplots (but no mapping, 

measurements, or enumerations are made). New or unrecognized species are collected in 

aluminum foil or plastic tackle boxes, and field identifications and distinctive characters are 

recorded by experienced field taxonomists. All fresh collections are then described, dried, and 

stored at WTU for later microscopic examination. Both plants and fungi also are inventoried 

during spring months. Since 1986, 215 fungus, 39 vascular plant, and 16 bryophyte species 

have been recorded.

Selection and training of conscientious qualified volunteers able to conduct a scientific 

investigation of this magnitude has been our most important consideration. Fortunately the 

approximately 80 years of taxonomic experience (Lindgren, Norvell, and Roger) and 40 years 

of forestry experience (Kopecky) brought to the study by the primary investigators have been 

augmented by additional expertise from over 50 enthusiastic volunteers. Despite a seemingly 

large volunteer pool, we found it easy and most efficient to use a relatively small work force 

composed of the same trained reliable individuals. The labor-intensive nature of our primary 

research-field work alone requires at least 15 annual visits (with an estimated 24 staff-hours 

per visit) for each of 10 projected years–leads almost inexorably to worker burnout, 

particularly as strict adherence to a biweekly sampling regimen often necessitates working in 

extremely unpleasant (wet and cold) weather. Dependence on a volunteer work force also has 

dictated the small scale of our study. If the chanterelles were only harvested and weighed (not 

measured, mapped, or tracked), or if only two treatments were applied (pull-harvest versus 

no-harvest), time spent on site could be reduced.

Unique

Considerations

70
Preliminary data indicate no difference between cut-harvest and pull-harvest. Our data agree 

with that of Egli and others (1990), who observed no difference between cutting or pulling of 15 

other edible species. The fact that our study (comparing treated and control plots over time) was 

the first of its kind, however, dictated that we attempt to provide as much baseline data as 

possible for future studies.

Although we are getting excellent data, they may not be applicable to other sites. Given the 

small scale of the study, we may be seeing harvest effects on only closely related, if not 

genetically identical, chanterelles in one forest location. Larger studies should be conducted 

and results compared.

The study's location behind locked gates in the Bull Run Watershed (first suggested and 

facilitated by Kopecky and the USDA Forest Service) has protected its integrity. We strongly 

suggest establishing any study of an economically valuable fungus (for example, chanterelle, 

matsutake, and morel) in similarly protected preserves when possible. The relative proximity of 

such a protected site to a metropolitan area also proved helpful: all microscopic examination and 

drying can be done in established labs rather than in temporary work stations.

Our greatest challenges have involved unknowns, uncontrollable variables, and unforeseen 

omissions. When we began the study, we did not know the age of our chanterelle mycelia, 

whether mycelia require spore influx to remain viable, or whether chanterelles have innate fruiting 

cycles. Although 8 years of data (5 years of harvesting data) indicate no statistically significant 

correlation between chanterelle harvesting and subsequent fruiting, the weather has been so 

variable as to make any conclusions premature and unreliable. Preliminary data do suggest a 

statistically significant correlation between warm summer temperatures and high chanterelle 

numbers (this correlation also has been cited by Danell 1994, Largent and others 1994, Ohenoja 

1993), but this is the only factor among many yet to be analyzed. Recent studies (KotilovaKubickova and others 1990a, 1990b, 1990c; Largent and others 1994; Vogt and others 1992) 

indicate that micrometerological data would prove more informative in tracking sporocarp 

production of Basidiomycetes than the generalized weather data we have obtained thus far. In 

spite of these problems, this study is the oldest continuing examination of chanterelle production 

and picking impacts.

After the 1996 field season, we intend to perform a full statistical analysis of the first 10 years of 

data and determine the genetic composition of the population through molecular techniques. 

Because even a 10-year study is too short to provide definitive answers, we hope to continue the 

study.

Egli, S.; Ayer F.; Chatelain, F. 1990. Der Einfluss des Pilzsammelns auf die Pilzflora. 

Mycologia Helvetica. 3(4): 417-428.

Danell, E. 1994. Cantharellus cibarius: mycorrhiza formation and ecology. Uppsala, Sweden: 

Acta Universitatis Upsaliensis. 58 p. Ph.D. dissertation.

Jansen, E.; van Dobben, H.; de Wit, T. 1985. Achteruitgang van de cantharel in 

Nederland. Wetenschappelijke Mededeling Koninklijke Nederlandse Natuurhistorische 

Vereniging. 167: 59-69.

Kotilova-Kubickova, L.; Ondol, J.P.; Priban, K. 1990a. Phenology and growth of

Dermocybe uliginosa in a willow carr. l: Phenology of fruiting. Mycological Research.

94: 762-768

71

Current Status

Literature Cited
.

72

Kotilova-Kubickova, L.; Ondol, J.P.; Priban, K. 1990b. Phenology and growth of 

Dermocybe uliginosa in a willow carr. II: Fruiting duration and performance. Mycological Research. 94: 769-773.

Kotilova-Kubickova, L.; Ondol, J.P. ; Priban, K. 1990c. Phenology and growth of 

Dermocybe uliginosa in a willow carr. III: Fruit-body growth and biomass production. 

Mycological Research. 94: 774-780.

Largent, D.; Hewlett, S.; Sime, D. 1994. Influence of environmental factors on fruiting of 

edible, mycorrhizal mushrooms. [Place of publication unknown]: [publisher unknown]; 

Final report; [contact unknown]. Prepared for: California Department of Forestry and Fire 

Protection.

Ohenoja, E. 1993. Effects of weather conditions on the larger fungi at different forest sites 

in northern Finland in 1976-1988. Oulu, Finland: University of Oulu. Ph.D. dissertation.

Vogt, K.A.; Bloomfield, J.; Ammirati, J.F.; Ammirati, S.R. 1992. Sporocarp produc tion 

by Basidiomycetes, with emphasis on forest ecosystems. In: Carroll, G.C.; Wicklow, 

D.T, eds. The fungal community, its organization and role in the ecosystem. 2d ed. New 

York: Marcel Dekker: 563-582.
Study 9: Effect of Environmental Factors and Timber

and Mushroom Harvest on Cantharellus Production

on the Olympic Peninsula, Washington State

Michael Amaranthus and Kenelm Russell 1 2

Changes in forest composition and structure likely affect fruiting of chanterelle (Cantharellus) 

species. Recent research (Amaranthus and others 1994) indicates that clearcutting can decrease 

truffle sporocarp production for two decades as compared to mature forest fragments. Luoma and 

others (1991), O'Dell and others (1992), and study 4 of this publication show differences in 

ectomycorrhizal fungus community structure among stands aged 25, 50, 80,160, and 400+ years. 

Forest thinning can reduce productivity of hypogeous fungi in 60- to 70-year old Douglas-fir 

stands." Little information, however, exists on chanterelle responses to forest thinning and various 

silvicultural systems. Such data are essential to predict impacts of forest harvest on mushroom 

production.

This study is on the Olympic Peninsula within 60-year-old stands dominated by western hemlock, 

Douglas-fir, and Sitka spruce and is an Integrated Research Site of the Long-Term Ecosystem 

Productivity Program of the USDA Forest Service. The integrated research and extended 

perspective offered by this study will produce needed information on interactions among 

chanterelle fruiting, environmental factors, mushroom harvesting, and forest density management.

Objectives were to:

1. Compare subsequent fruiting among plots where chanterelles are harvested and not 

harvested.

2. Correlate sporocarp production with soil temperature, air temperature, and moisture variables.

3. Compare chanterelle production in stands thinned to produce forest composition and structure 

typical of early, middle, and late seral stages (and a no-timber-harvest control).

Including the no-timber-harvest control, the study design consists of 4 treatment stands in each of 

3 blocks for a total of 12 treatment stands. Chanterelle production is sampled once monthly from 

mid-August to mid-December. Chanterelle sporocarp production has a strong seasonal aspect in 

our region, and sampling over a 5-month period will ensure capturing not only biomass production 

but also changes in soil

1Michael Amaranthus is with the U.S. Department of Agriculture, Forest Service, Pacific Northwest Research 

Station, Grants Pass, OR 97526; and Kenelm Russell is with the Washington Department of Natural 

Resources, Olympia, WA 98504.

2Cooperators were David Arthur, Siskiyou National Forest, Grants Pass, OR 97526; and Richard Bigley and Jim 

Arthurs, Washington Department of Natural Resources, Olympia WA 98504.

3Upublished data. 1995. James Trappe and Wes Colgan III Department of Forest Science, Oregon State 

University, Corvallis, OR 97331.

73

Context

Objectives

Methods and 

Rationale
moisture and temperature on the site. Two years of baseline data on chanterelle production 

have been collected, and timber-harvest treatments were scheduled for spring 1995. Posttreatment chanterelle sampling will occur at years 1, 2, 3, 5, 10, and 20 and every 20 years 

thereafter.

Chanterelle mushrooms are sampled within four strip plots (8 by 100 meters [26 by 328 ft.]) 

located in each forest harvest treatment. One-half of each transect (4 by 100 meters) was 

randomly selected as either a chanterelle-harvest or no-harvest treatment. In the 

chanterelle-harvested portion of each transect, all mushrooms are cut at the soil surface with a 

knife and placed in sealed plastic bags in a cooler. Size and weight are measured within 24 

hours of collection. Cap width (at widest point), total mushroom height, and basal stem 

diameter (where cut) are measured to the nearest millimeter, and fresh weight recorded to the 

nearest one-tenth of a gram. A subsample of mushrooms is dried and weighed to determine 

average moisture content during each sampling period. In the no-harvest half of each strip plot, 

cap diameter and mushroom height are measured in the field for each chanterelle mushroom. 

Regression equations (derived from the harvested mushrooms) of size, fresh weight, and dry 

weight will be used to estimate chanterelle biomass in the measured, but not harvested, 

portions of each plot.

Additional data collected include fruiting of chanterelle species other than C. cibarius and C.

subalbidus (the commercially harvested species), mycophagy, and forest floor vegetation and 

litter (moss, salal, decayed wood, and so forth). For future identification, a colored plastic 

toothpick is inserted in each inventoried, but not harvested, mushroom. During each visit, soil 

moisture and temperature are determined at a 10 centimeter (3.93-in.) depth at the end points 

of two center strip plots in each stand. Air temperature and soil surface temperature also are 

recorded at each of the three blocks.

Most other studies of chanterelle production have lacked integration with investigations of other 

ecosystem components. Other research activities on the site and the extended perspective 

offered by this integrated project will produce information on interactions between fruiting of 

mycorrhizal fungi and environmental factors, such as soil compac tion, stand conditions, and 

timber harvesting.

Two years of pretreatment data (autumn 1993 and 1994) have been collected. Total and 

monthly production was much higher in autumn 1994 than in autumn 1993. Chanterelle 

numbers and total dry weight have been significantly greater, during both seasons, in areas 

with only moss on the forest floor than in areas covered with sparse salal, dense salal, or 

decayed wood. Chanterelle harvest has not yet significantly affected chanterelle numbers or 

dry weight. Timber harvest began in summer 1995, and chanterelles were again sampled that 

autumn.

Amaranthus, M.P.; Trappe, J.M; Bednar, L.; Arthur, D. 1994. Production of hypogeous 

fungi in managed and unmanaged habitats of southwest Oregon. Canadian Journal of 

Forestry Research. 24: 2,157-2,165

Luoma, D.L.; Frenkel, R.E.; Trappe, J.M. 1991. Fruiting of hypogeous sporocarps in Oregon 

Douglas-fir forests: seasonal and habitat variation. Mycologia. 83: 335-353.

O' Dell, T.E.; Luoma, D.L.; Molina, R.J. 1992. Ectomycorrhizal fungal communities in

young, managed and old growth Douglas-fir stands. Northwest Environmental

Journal. 8: 166-168.

Unique Considerations

Current status

Literature Cited

74
Study 10: Matsutake Productivity and Ecology 

Plots in Southern Oregon

David Pilz, Chris Fischer, Randy Molina, Michael Amaranthus, 

and Daniel Luoma1 2

The production of the Japanese matsutake mushroom (Tricholoma matsutake) has declined in 

Japan (Kawai and Ogawa 1981) while demand continues to increase (The Japan Trade 

Development Division 1990). Korea supplies much of the matsutake market, but harvesting of 

the American matsutake (T. magnivelare) in the Pacific Northwest also has expanded 

dramatically. They are now harvested from northern British Columbia and southeast Alaska, 

south through coastal pine forests and the eastern crest of the Cascade Range in Washington 

and Oregon, to the Siskiyou and Klamath Mountains of southwest Oregon and northwest 

California. In Oregon alone, about 204,545 kilograms (450,000 pounds) valued at $4,350,000 

were harvested in 1992 (Schlosser and Blatner 1995). Much of the Oregon harvest of 

matsutake mushrooms is collected from Federal lands on the east side of the Cascade Range 

near Chemult and in the Siskiyou Mountains of southwest Oregon. Burgeoning mushroom 

harvest activities preceded monitoring of matsutake productivity and adequate understanding of 

its ecology. Matsutake fruiting differs greatly from year to year, so quick establishment of 

baseline productivity study sites was deemed essential to begin gathering inventory and 

ecological data. The applicability of fungus diversity sampling methods to the measurement of a 

single species of edible mushroom also needed evaluation.

Objectives were to:

1. Determine biomass production of matsutake sporocarps from permanent plots in designated 

study areas and from watersheds where matsutakes are commercially harvested.

2. Correlate sporocarp production with vegetation, soil, and temperature parameters.

4. Develop cost-effective methods to inventory, predict, and compare productivity of edible 

mushrooms in different regions.

This study was installed in Oregon on the Chemult Ranger District of the Winema National 

Forest, the Illinois Valley Ranger District of the Siskiyou National Forest, and the BLM Medford 

District. Each long-term study site is 225 by 225 meters (740 ft.) for a total area of 5 hectares 

(12.4 acres). These sites were located in inaccessible areas wherever possible, and signs 

restricting recreational or commercial collecting were

1David Pilz, Chris Fischer, and Randy Molina are with the U.S. Department of Agriculture, Forest Service, 

Pacific Northwest Research Station, Corvallis, OR 97331; Michael Amaranthus is with the U.S. Department of 

Agriculture, Forest Service, Pacific Northwest Research Station, Grants Pass, OR 97526; and Daniel Luoma is 

with the Department of Forest Science, Oregon State University, Corvallis, OR 97331.

2Cooperators were Gerry Smith, Chemult Ranger District, Winema National Forest; Rudy Wiedenbeck and David 

Arthur, Siskiyou National Forest; and Kathy Browning, Medford District, Bureau of Land Management.

75

Context

Objectives

Methods and Rationale
posted. At Chemult, three sections (square miles) were designated for study purposes. 

Matsutake production was evaluated within six permanent 2- by 50-meter (6.6 by 164-ft.)strip 

plots located systematically and oriented randomly within each study site for a total sample area 

of 600 square meters (6,460 ft.2) per site. Study sites were selected on different aspects and 

elevations within the dominant plant community types to allow extrapolation of results to a 

broader landscape context.

To estimate biomass of the matsutakes without harvesting them, the following measurements 

were made after the veil of each mushroom had broken: (1) cap diameter, (2) stem diameter at 

point of annulus attachment, and (3) vertical distance from annulus to top of cap. Once 

measured, each mushroom was marked so that it would not be remeasured. Other matsutakes 

were collected outside the plots to develop correlations between size and weight, so that the 

biomass of unharvested sporocarps within the plots could be estimated from their size 

measurements. Plots were surveyed weekly through the fruiting season until no new sporocarps 

were located or the site was covered with snow. A percentage of volume removed was 

estimated for partially eaten sporocarps. Data on fungus consumption by animals will provide 

valuable information about potential effects of human competition for a wildlife food resource.

Distance to the nearest tree or shrub species also was determined for each mushroom. These 

data may reveal fungus-host associations important for managers to understand for long-term 

maintenance of matsutake populations. Weekly temperature and moisture data will be obtained 

from the nearest weather station and correlated with estimates of matsutake biomass 

production.

At the Illinois Valley Ranger District, we also attempted to weigh all mushrooms collected by 

harvesters from a discrete watershed having only one access road. A station was set up to 

monitor what collectors brought out at the end of each day.

Many valuable lessons were learned from field experience during autumn 1993. These study 

plots were too expensive and time consuming to use for randomly sampling productivity of likely 

habitats without foreknowledge of fruiting on the site. The sample area of the strip plots on each 

site was far too small to adequately sample a single mushroom species, except in areas of 

known heavy fruiting, such as the Chemult sites. Many study sites were compromised by illegal 

picking unless they were located far beyond a road gate. Some "no picking" signs were simply 

ignored because the matsutakes are so valuable. Some sites were intentionally harvested by 

indignant local pickers, and one gate was even pulled out of the ground. Weighing the 

commercial harvest from a given watershed was problematic because the weighing station was 

time consuming to operate and intimidating to harvesters, among whom prior arrangements had 

not been made. Correlations of fruiting with weather may be stronger if data were collected on 

the site rather than from distant weather stations (especially in mountainous and forested terrain 

where microclimate variations are great over small distances), but local stations are expensive.

Dry weather limited fruiting in the Siskiyou Mountains during the 1993 season and only a few 

matsutakes were found on two of the nine sites. The Illinois Valley Ranger District study sites 

were abandoned to free personnel for pursuing more cost-effective monitoring approaches. 

One of the BLM sites was monitored in 1994, but dry, cold weather prevented fruiting. The 

Chemult sites were sampled from 1993 to 1995 and data are being analyzed.

Unique Considerations

Current Status

76
77

Kawai, M.; Ogawa, M. 1981. Some approaches to the cultivation of a mycorrhizal fungus, 

Tricholoma matsutake (Ito et Imai) Sing. In: Mushroom science XI, Part 2: Proceedings of 

11th international scientific congress on the cultivation of edible fungi; 1981 [day and month 

unknown]; Sydney, Australia. [Place of publication unknown]; [publisher unknown]: 

869-883.

Schlosser; W.E.; Blatner, K.A. 1995. The wild edible mushroom industry of Washington, 

Oregon and Idaho: a 1992 survey. Journal of Forestry. 93: 31-36.

The Japan Trade Development Division. 1990. The mushroom market. Export 

Opportunities in Japan Series [no. unknown]. Ottawa, ON: External Affairs and 

International Trade Canada.

Literature Cited
Study 11: Matsutake Inventories and Harvesting Impacts in the 

Oregon Dunes National Recreation Area

David Pilz, Randy Molina, Michael Amaranthus, Daniel 

Segotta, and Frank Duran 1 2

The Oregon Dunes National Recreation Area (ODNRA) of the Siuslaw National Forest is located 

along the central Oregon coast between Florence and Coos Bay. Matsutake mushrooms have 

been commercially harvested for decades from shore pine (Pinus contorta var. contorta) forests on 

the dunes, but harvesting pressure increased dramatically in the last 5 years as the value of 

matsutakes became widely known. To manage the resource appropriately, the Siuslaw National 

Forest dedicated funds in 1994 and 1995 for monitoring production and examining harvest impacts. 

After considering a variety of monitoring methods, the ODNRA decided to participate in a 

matsutake monitoring program designed by Michael Amaranthus and described here. To compare 

results regionally, this study design is also being implemented at the Diamond Lake Ranger 

District, Umpqua National Forest; the Chemult Ranger District, Winema National Forest; the 

Boswell Mine near Cave Junction; and the Medford District BLM.

Objectives were to:

1. Determine matsutake production (sporocarp biomass) and value from long-term study 

plots in a known matustake fruiting area.

2. Evaluate the effects of various mushroom harvesting techniques on matsutake production.

In 1994 we delineated clusters of matsutakes for application of experimental treatments in 

subsequent years. Mushrooms were individually collected, graded, and weighed, and each tenth 

mushroom was dried and weighed. We mapped each mushroom relative to a reference tree. We 

then used Global Positioning System equipment to pinpoint these trees so that clusters could be 

mapped relative to each other and easily relocated. First-year mapping and weighing allowed us to 

(1) choose clusters of sporocarps for application of experimental treatments in subsequent years, 

(2) determine per-unit-area productivity of matsutake mushrooms on the study site, and (3) identify 

surplus clusters for use in other field studies, such as examination of matsutake physiology, 

reproduction, population genetics, and response to microclimatic variables.

Treatments were implemented in 1995. Clusters were defined to include mushrooms no further 

than 0.5 meter (1.6 ft) apart with distances between clusters being greater than 2 meters (6.6 ft). 

Replicated blocks of clusters were used to examine the influence of vegetation type on mushroom 

productivity and response to treatments. Within each of three blocks, six clusters with similar 

matsutake production were selected and randomly assigned one of the six following treatments:

1David Pilz and Randy Molina are with the U.S. Department of Agriculture, Forest Service, Pacific Northwest Research 

Station, Corvallis, OR 97331; Michael Amaranthus is with the U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Research Station, Grants Pass, OR 97526; and Daniel Segotta and Frank Duran are with the Siuslaw National 

Forest, Corvallis, OR.

2Cooperating were Ed Strawn and Dwight Reindle, commercial matsutake harvesters from the Oregon Dunes.

Context

Objectives

Methods and 

Rationale

78
79

1. No harvest control.

2. Harvest with minimal disturbance (gentle rocking and pulling) and replacement of duff.

3. Total removal of litter and duff layer by raking (to the surface of the matsutake mycelial 

layer), sporocarp removal, and careful replacement of the duff.

4. Total removal of litter and duff layer by raking (to the surface of matsutake mycelial layer) 

sporocarp removal, and no replacement of the duff.

5. Total removal of litter and duff layer by raking (deep raking through the matsutake mycelial 

layer), sporocarp removal, and duff replacement.

6. Total removal of litter and duff layer by raking (deep raking through the matsutake mycelial 

layer), sporocarp removal, and no replacement of the duff.

These treatments are designed to answer questions about the impact of harvesting itself and 

the potential damage of searching techniques used by some harvesters to locate the valuable 

small mushrooms that have not yet emerged through the forest duff layer.

To characterize climatic differences among the study sites, maximum and minimum soil and air 

temperature will be determined at 1-week intervals beginning August 1 and extending 2 weeks 

past the fruiting period in each location.

Mapping individual sporocarp locations was labor intensive but provided a valuable foundation 

for long-term studies, because sporocarps occur in nearly the same spot each year. In 

Japanese studies, matsutake sporocarps appear in arcs on the leading edge of mycelial mats 

called shiros that advance through the soil only a few centimeters per year (Ogawa 1975, 

Tominaga 1971). Our initial mapping indicated that fruiting patterns of the American matsutake 

may be more diffuse than those of the Japanese matsutake. Selection of clusters for application 

of experimental treatments was based on proximity of sporocarps to each other rather than the 

excavations of mycelial mats needed to define shiros. Fruiting in 1994 was sufficiently heavy to 

proceed with cluster selection and application of experimental treatments in 1995. Rapidly 

increasing demand for commercial matsutake harvest privileges has lent urgency to obtaining 

results of harvest impacts.

Security of the study site is a major consideration. We have cooperated with commercial 

collectors throughout the study to keep the surrounding area thoroughly harvested, thus 

discouraging unauthorized harvesters. Our cooperators are skilled at noting evidence of visits by 

other harvesters. During application of the experimental treat ments, mushrooms left in the 

control clusters were marked to destroy their commercial value. Arrangements for regular visits 

by dedicated law enforcement officers was necessary to reduce vandalism of the study site. In 

1995, the study site was closed to the general public during the fruiting season to allow officers 

to cite anyone found in the area, because it was often difficult to catch unauthorized harvesters 

with mushrooms in their possession.

Commercial production (rather than total biological) will be measured in this study because 

treatment applications and sampling procedures are designed to mimic what

Unique

Considerations
80

typically occurs during commercial harvesting activities. Annual production of matsutake 

differs greatly, and conclusions about averages, extremes, and trends must be based on 

data collected over many years. Likewise, the potentially harmful effects of experimental 

treatments may not become apparent for several years. This study will provide 

increasingly valuable insights as new data accumulate from each season.

The 1994 field season at the Dunes study site was productive. Nearly a hundred 

reference trees were used to locate from 20 to 100 sporocarps each. The season began 

in early November, peaked in early December, and finished in early January. At least half 

of the clusters (temporarily defined by the reference trees) showed evidence of tampering 

by unauthorized harvesters, but we had sufficient undisturbed clusters to apply 

experimental treatments in 1995. Site security was enhanced in 1995. Results of the 

mapping and first-year treatment applications will be published in 1996.

Study activities are proceeding concurrently at the Diamond Lake site. Mapping began in 

1995 at the Chemult, Boswell Mine, and Medford sites, and treatments will be applied in 

1996.3

Ogawa, M. 1975. Microbial ecology of mycorrhizal fungus, Tricholoma matsutake (Ito et 

Imai) Sing. In: pine forest 1: Fungal colony ('Shiro') of Tricholoma matsutake. Bull. 

272. Tokyo, Japan: Government Forest Experiment Station.

Tominaga, Y. 1971. Studies on the formation and development of the fruit body of 

Armillaria matsutake (Ito et Imai). Bulletin Hiroshima Agricultural College. 4: 106-122.

3Concurrent studies are being coordinated by Rick Abbott, USDA Forest Service, Diamond Lake Ranger District, Umpqua National 

Forest, Idleyld Park, OR 97447; Jerry Smith, USDA Forest Service, Chemult Ranger District, Winema National Forest, Chemult, 

OR 97731; and Mike Amaranthus, USDA Forest Service, Pacific Northwest Research Station, Grants Pass, OR 97526. 

Cooperating on these sites is Andy Moore, commercial matsutake harvester, Cave Junction, OR 97523.

Current Status

Literature Cited
81

Study 12: Chanterelle Production Responses 

to Stand Thinning

David Pilz, Randy Molina, and Jim Mayo 1 2

Norvell and others (1995) (also see study 8) examine the impact of harvesting chanterelles and 

David Largent and others (1994) correlate the fruiting phenology of chanterelles with 

microenvironmental variables. This study and study 9 are the only known examinations of 

timber management impacts on chanterelle productivity.

This study was added to an integrated research project, "Young Stand Thinning and Diversity 

Study," an administrative study sponsored by the USDA Forest Service, Willamette National 

Forest, in the central Oregon Cascade Range. The project was designed to examine how 

various stand-thinning techniques and leave-tree densities affect site conditions and ecological 

responses, including the production and quality of special forest products such as chanterelles.

Objectives were to:

1. Determine how large an area must be sampled to produce adequate estimates of 

chanterelle productivity on a given site.

2. Examine the impacts of stand thinning on subsequent chanterelle production.

Four young (30 to 50 years old) Douglas-fir stands in the Oakridge, Blue River, and McKenzie 

Ranger Districts of the Willamette National Forest were selected as study blocks. At each 

location, three logging treatments are being examined that include an unthinned control and two 

thinning intensities (124 residual trees per hectare [50/acre] and 297 residual trees per hectare 

[120/acre]). Productivity is being estimated by collecting chanterelles along systematically 

located strip plots. The effects of thinning will be assessed by comparing the relative increase or 

decrease from baseline fruiting in thinned stands to the seasonal increase or decrease from 

baseline fruiting in unthinned stands. We will also compare the impact of stand thinning 

operations by sampling permanently marked areas of dense chanterelle fruiting.

Annual fruiting patterns are highly variable, so supervisors must be flexible in scheduling work

crews. We designed our sampling for what we considered feasible in a year with heavy 

production and will undertake optional tasks when fruiting is light. Facilities, space, and 

equipment must be arranged to regularly sort, weigh, and dry large numbers of chanterelles.

1David Pilz and Randy Molina are with the U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331; 

and Jim Mayo is with U.S. Department of Agriculture, Forest Service, Willamette National Forest, Blue River Ranger District, Blue River, OR 97413.

2Cooperators were John Tappeiner, Department of Forest Science, Oregon State University, Corvallis, OR 97331; USDA Forest Service, 

Willamette National Forest, the Blue River, McKenzie, and Oakridge Ranger Districts; and the Cascade Center for Ecosystem Management.

Context

Objectives

Methods and

Rationale

Unique

Considerations
82

Permanently marking mushroom patches so that they can be located after logging 

operations is difficult. Nearest leave trees were identified, located, and marked. Plot 

centers were marked with rebar driven into the ground to avoid puncturing logging tractors 

tires. If necessary, metal detectors can be used to relocate the rebar. Planned skid trails 

were avoided as chanterelle patches were selected. Some patches may be damaged or 

destroyed by slash burn piles, or slash may have to be moved to facilitate sampling. Slash 

also may make walking on inventory strip plots difficult after logging. Other researchers 

were informed not to pick chanterelles for personal use.

We benefit from work performed by other cooperators; our methods and design were 

limited, however, by choices made by the original designers of the integrated research 

project. Coordination is required to uniquely mark plot locations, because many other 

studies are occurring in the same stands. Timber harvest studies on National Forest lands 

may encounter legal challenges that prevent or delay logging.

Only 1 year of baseline productivity data on fruiting patterns (1994) was obtained, but 

chanterelles were found in all stands. Commercial thinning operations were/are 

scheduled for 1995 and 1996. Only control stands were sampled in 1995. The first 

season of post-logging surveys is scheduled for autumn 1996.

Largent, D.; Hewlett, S.; Sime, D. 1994. Influence of environmental factors on fruiting of 

edible, mycorrhizal mushrooms. [Place of publication unknown]; [Publisher unknown]; 

final report; [contact unknown]. Prepared for: California Department of Forestry and Fire 

Protection.

Norvell, L.; Kopecky, F.; Lindgren, J.; Roger, J. 1995. The chanterelle (Cantharellus 

cibarius): a peek at productivity. In: Schnepf, Chris, comp., ed. Dancing with the 

elephant: Proceedings: The business and science of special forest products–a 

conference and exposition; 1994 Jan. 26-27; Hillsboro, OR. [Place of publication 

unknown]; University of Idaho Extension Service: 117-128. Sponsored by: Northwest 

Forest Products Association; Western Forestry and Conservation Association.

Current Status

Literature Cited
Study 13: Shiro Analysis of Matsutake in the

Central Washington Cascade Range

David R. Hosford 

1 2

As harvests of native matsutake diminished, Japanese importers began looking to the U.S. Pacific 

Northwest to supply similar mushrooms. As a representative of their interests, H. Ohara, a matsutake 

specialist, came to the Pacific Northwest in 1980 to assess the quantity and quality of matsutake, 

"pine mushroom," in Washington State. It was during his visit that we first met and together located 

matsutake "shiros" (literally, castle or domain of the fungus) in central Washington. Later, during my 

visit to Japan, we laid the foundation for future collaboration. In 1985, we began a 5-year study of 

Tricholoma magnivelare in central Washington using the Kyoto or "Shiro" method developed 

principally by Hamada (1955), Ogawa and Hamada (1965), Ohara (1966), and Ohara and Hamada 

(1967).

As the commercial value of matsutake became more widely recognized, our study attracted the 

attention of forest researchers, managers, and harvesters specifically interested in mycorrhizae, 

sporocarp productivity, and habitat management. This study, the first of its kind in the Pacific 

Northwest, has provided baseline information on the ecology of matsutake and has led to new 

studies throughout the region.

Objectives for each Shiro analysis were to:

1. Mark the seasonal location of each sporocarp.

2. Map the horizontal and vertical position of the mycelium.

3. Calculate total sporocarp productivity per season.

4. Determine the maturation interval in days from primordia to fully opened sporocarps.

5. Collect and identify associated species of mushrooms.

6. Identify all associated plant species and determine plant community structure and composition.

7. Determine soil type, profile, pH, temperatures, and moistures.

8. Collect roots, soil, and young sporocarps for study of mycorrhizae, microbial populations, and 

somatic cultures, respectively.

The shiro is defined here as the soil microhabitat that is influenced by mycelial growth and 

mycorrhizal development; it is the fundamental ecological unit in the study of mycorrhizal fungi. 

From studies of T. matsutake shiros, Japanese researchers have developed forest management 

techniques to establish new shiros in pine forests or to

1David Hosford is with the Department of Biological Sciences, Central Washington University, Ellensburg, WA 98926.

2Cooperators were Hiroyuki Ohara, Laboratory of Biology, Doshisha Women's University, Kyoto, 602, Japan; Makoto Ogawa, Biological 

Env ironmental Institute, Kansai Environmental Engineering Center, 8-4 Ujimatafuri, Uji, Kyoto, 611, Japan; and the Wenatchee National Forest, 

Cle Elum Ranger District.

83

Context

Objectives

Methods

And

Rationale
enhance sporocarp productivity in established shiros (Ogawa 1982). With this management possibility in mind, we began our baseline study of T. magnivelare shiros to 

better understand its ecology and productivity.

In autumn, 1985, four sites with 19 shiros, were located in the central Washington Cascade 

Range. Each site was described in detail including topography, climate, soil type, and 

vegetation. From late August through mid-November, each shiro was monitored one to 

three times per week for the appearance of matsutake and other mushrooms species. 

Numbers of sporocarps were counted and their position in the shiro marked by color-coded 

flags; different colors represented different years. The relative position of fungal mycelium 

and host roots to the flags was determined, and annual growth or advancement of the 

mycelium mapped. Flags also provided an accurate reference point for obtaining 

mycorrhizae or soil samples from the active mycorrhizal zone and from immediately 

adjacent soil (Ohara and Hamada 1967). Harvested sporocarps were weighed and either 

dried for later study or used to obtain somatic cultures and spore prints. Mature (fully 

opened) and decaying sporocarps were counted and marked, but left in place.

For long-term study, selected shiros should ideally be close to the research facility to allow 

frequent monitoring, yet distant to regular public access so that they are protected from 

unwanted visitors. Such criteria are difficult to meet. Our 19 shiros were scattered in four sites 

with some on private and others on public lands. Unfortunately, by the end of the study only 

nine shiros remained as a result of clearcut logging. Cooperation among land owners, 

managers, and researchers is needed to dedicate research sites for such long-term study. 

Low levels of fruiting in the dry seasons in 1987 and 1989 also impacted our study.

Shiro analysis involves flagging, collecting, identifying, weighing, and curating samples, 

extremely time consuming and labor intensive activities. At the beginning of our study, we 

monitored 19 shiros one to three times per week. Each trip took about 10 hours in the field, 

including travel time, followed by 10 to 16 hours of laboratory study. We averaged 46 hours 

per week per researcher the first season. From 1986 to 1989, I worked alone and had to 

reduce field trips to one per week and monitoring to two shiros per site (total of eight). Even 

so, the work load was overwhelming. Those interested in this type of research need field staff 

adequate to the task of monitoring the selected number of shiros.

Study results have been summarized by Hosford and Ohara (1986, 1990, 1995). From 1990 

to 1993, the nine remaining sites were visited sporadically; productivity was low due to 

extreme drought. In 1994, we began regular monitoring of shiros for sporocarp productivity 

and soil microbiology. Daily weather conditions, precipitation, and soil temperatures are now 

recorded year-round. Future collaboration with colleagues in Japan and the USDA Forest 

Service on mycorrhizae, DNA, and microbial populations is anticipated. Based on our initial 

forest habitat analysis, preliminary GIS (Geographic Information Service) mapping of 

potential matsutake sites in the central Washington Cascade Range is underway.

Unique

Considerations

Current Status

84
85

Hamada, M. 1955. [Title not translated]. Kanzume Jiho. 34: 1-7. In Japanese.

Hosford, D.; Ohara, H. 1986. Shiro analysis of mycorrhizal fungi. [Abstract]. In: 

Roots in forest soils: biology and symbioses: Meeting of the IUFRO working party 

on root physiology and symbioses (S2.01-13); 1986 August 4-8; Victoria, BC. 

[Place of publication unknown]: [publisher unknown].

Hosford, D.; Ohara, H. 1990. Ecological characterization of American matsutake. 

In: Abstracts: bacteriology and mycology. Osaka, Japan: International Union of 

Microbiological Societies Congress.

Hosford, D.; Ohara, H. 1995. Ecological study of Tricholoma magnivelare shiros in 

central Washington. In: Schnepf, C., comp., ed. Dancing with the elephant: 

Proceedings: The business and science of special forest products–a conference

and exposition; 1994 Jan. 26-27; Hillsboro, OR. [Place of publication unknown]; 

University of Idaho Extension Service: 111-116. Sponsored by: Northwest Forest 

Products Association; Western Forestry and Conservation Association.

Ogawa, M. 1982. How to produce matsutake mushroom. Nara, Japan: Matsutake 

Research and Consultation Office. Forest Service Research Station, Nara, 

Japan: 158 p.

Ogawa, M.; Hamada, M. 1965. [Title not translated]. Transactions of the 

Mycological Society of Japan. 6: 67-71. In Japanese.

Ohara, H. 1966. [Title not translated]. Proceedings of the Japan Academy. 42: 

503-506. In Japanese.

Ohara, H.; Hamada, M. 1967. Disappearance of bacteria from the zone of active 

mycorrhizas in Trlcholoma matsutake (S. Ito et Imai) Singer. Nature. 213: 

528-529.

Literature Cited
Forest Fungi and Ecosystem 

Management

David Pilz, Randy Molina, Michael Amaranthus, Michael 

Castellano, and Nancy S. Weber 1

What exactly is "ecosystem management"? Simply put, it is a holistic approach to 

managing land. It is based on understanding and maintaining the components (for 

example, species), interactions (for example, food webs), and processes (biological, 

chemical, and physical) of ecological systems, while simultaneously producing products 

and services for society. As applied to Federal forests in the United States, a goal of 

ecosystem management is full implementation of forest management directives found 

in Federal legislation. (For a concise review of pertinent laws, see Cubbage and others 

1993: 528-539.) Previous efforts to implement this body of legislation have been 

challenged repeatedly with administrative appeals, lawsuits, and laws that preclude 

judicial review. Nevertheless, their basic tenets are widely accepted among scientists, 

managers, and the general public: namely, public forests should provide a wide variety 

of amenities and uses in perpetuity.

In recent decades, the public has demanded a broader spectrum of recreational 

opportunities and commercial goods from public forests. Concurrently, scientists have 

expanded our understanding of the critical role that biological diversity plays in sustaining long-term production of many services and commodities we derive from forest 

ecosystems. Fungi are essential functional components of forest ecosystems and 

directly provide humans with valued products.

1David Pilz, Randy Molina, and Michael Castellano are with the U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Research Station, Forestry Sciences Laboratory, 3200 Jefferson Way, Corvallis, OR 97331; Michael 

Amaranthus is with the U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Grants Pass, 

OR 97526; and Nancy Weber is with the Department of Forest Science, Oregon State University, Corvallis, OR 97331.

Illustrated Principles 

of Ecosystem 

Management

86
87

Conserving Diversity

In this chapter, we briefly describe the following principles of ecosystem 

management and illustrate them with examples of managing forest fungi:

• Conserving diversity is essential to sustaining ecosystem productivity

• Management must account for the dynamic nature of ecosystems

• Ecosystem processes must be managed across multiple scales and land ownerships

• People are an integral part of ecosystems and their successful management

• Adaptive management requires continuous monitoring and research

These principles are excerpted from recent publications that discuss in detail the 

meaning of ecosystem management and its application to public forests (Bormann and 

others 1994, Jensen and Everett 1994, Kaufmann and others 1994, Marcot and others 

1994, Moote and others 1994, Overbay 1992). After discussing examples of how these 

principles relate to forest fungi, we examine methods for integrating the management 

of forest fungi into the larger context of ecosystem management.

An underlying premise of efforts to preserve diversity is the recognition that we cannot 

know all the functional roles each organism, population, or species has in an ecosystem. In many cases, their importance is clear and their functions invaluable, but 

scientists are continually surprised with discoveries about the significance of unusual, 

obscure, or seemingly minor species. Although species frequently exhibit overlapping 

functions in ecosystem processes, a given species can be specially adapted to a 

narrow environmental niche, thereby allowing it to function more effectively than 

competitors. In ecosystems with diverse biota, numerous species with precise adaptations use the physical environment more efficiently than a few species with imprecise or 

general adaptations, thus enhancing ecosystem productivity. We are just beginning to 

understand how important the diverse fungus community of Pacific Northwest forests is 

to the growth of trees and the vast array of other forest organisms.

No officially threatened or endangered fungus species is currently listed on the Federal 

Register, but through the Forest Ecosystem Management Assessment Team (FEMAT 

1993) process, and in the general mycological community, many fungus species are 

considered rare, uncommon, or threatened, Oxyporus nobilissimus was listed with the 

Natural Heritage Program in Oregon by John Christy.2 to 1994, Joseph Ammirati3

submitted "A preliminary list of uncommon, sensitive, rare, and/or endangered macrofungi in Washington State" to the Washington Department of Natural Resources 

Natural Heritage Program, but no official action was taken on it. Rare or endangered 

fungi need to be listed if they are to be protected within the context of our forestry 

practices. Germany, the Netherlands, and Sweden have developed such "red" lists for 

fungi whose abundance has declined dramatically (Arnolds 1991, 1992). The list 

created from the FEMAT process is a logical starting point, but habitats outside the 

range of the northern spotted owl and within other ownerships must be considered 

when determining the status of each species

2John Christy, Wetlands and Aquatics Ecologist, Oregon office, The Nature Conservancy, 821 SE 14th 

Avenue, Portland, OR 97214.

3Joe Ammirati, head of the Botany Department, University of Washington, Seattle, WA 98195.
88

Well-documented species distinctions are requisite to accurate listing, and valuable for 

managers designing measures to protect rare species. Fungi have complex matingcompatibility factors, and many are difficult or impossible to culture and mate in vitro; 

thus the biological species definition of mating compatibility (with fertile offspring) 

within, but not among, species is difficult to verify in most cases. Currently, most 

fungus species are predominantly defined by sets of morphological characteristics, but 

mycological taxonomists constantly debate meaningful criteria for defining a unique 

species, and are sometimes referred to as "lumpers" or "splitters," depending on how 

many species they recognize. Molecular techniques of genetic analysis are providing 

additional information for resolving some species concepts.

In addition to accurate species distinctions, the process of listing fungi should detail 

criteria for determining rareness and assigning threatened status, as well as removing 

species from protection lists as new information becomes available or populations 

expand. We can adopt much of the process that the native plant societies have used 

for vascular plants. A panel of regional experts, using agreed upon criteria, should 

annually evaluate species for addition to, or removal from, lists. Information used by 

the panel should be widely disseminated, so that managers can judge the importance 

of conserving local populations.

Conservation of diversity is important for sustaining the harvest of wild, edible fungi as 

well. The wide variety of edible fungi with their individual habitats and fruiting seasons 

provides opportunities in the Pacific Northwest to gather mushrooms or truffles throughout most of the year. Genetic diversity within edible fungus populations likely allows 

specific adaptations to local habitats and, consequently, greater sporocarp production 

than if fungus populations were genetically uniform. Appropriate management of edible 

fungi will require a greater understanding of diversity within and among populations and 

the importance of that diversity to survival, reproduction, sporocarp production, and 

long-term viability of each species.

All populations of living organisms are influenced by a wide range of factors such as 

climate, soil, disturbance processes, other plants and animals, and people. These 

factors are unpredictable and fluctuate in a manner that greatly influences the abundance and distribution of mushroom species and populations. As with all organisms, 

local extinctions, invasions, migrations, or successions of mushroom taxa inevitably 

occur without any human influence (Groombridge 1992) but can be greatly accelerated 

or interrupted by human activities (Arnolds 1991).

Forests change slowly and incrementally as they age. Sporocarp studies suggest that 

groups or guilds of ectomycorrhizal fungi shift in composition as forests age (see 

citations in study 4), and parasitic and saprobic fungi find more habitat as trees reach 

maturity and woody debris increases in a forest (Arnolds 1989). Edible mushrooms 

can occur in all stages of coniferous forest stand development; however, edible 

ectomycorrhizal species such as chanterelles, matsutake, and boletes occur most 

abundantly in mid-successional stages of development.

Forests also change rapidly and dramatically when disturbed by storms, wildfires, or 

logging. Disturbance (and the process of recovery from disturbance) is common to all 

ecosystems, and fungi have evolved responses. For example, some form

Dynamic Nature 

of Ecosystems
ectomycorrhizae with brushy hosts that sprout quickly after logging or a fire that kills coniferous 

hosts (Amaranthus and Perry 1989, 1994; Molina and others 1992), thereby enabling the fungi to 

persist on the site until new trees become established. While clearcutting is an efficient means of 

timber harvest, and mycelial colonies of ectomycorrhizal fungi, such as chanterelles, boletes, 

and matsutakes, could conceivably persist on a site if new conifer hosts become promptly 

established, fruiting is likely to be greatly reduced or eliminated until the new stand accumulates 

sufficient carbohydrates from photosynthesis to support sporocarp production. In the southern 

Cascade Range of Oregon, chanterelles can be collected in partially harvested stands. 

Matsutakes were abundantly produced in some ashfall areas of the Mount St. Helens eruption in 

Washington where host trees were not killed (Amaranthus, unpublished data). Some morel 

species are known to fruit prolifically in response to disturbances such as fire, soil movement, or 

tree mortality. On the other hand, disturbances that differ in type, frequency, or severity from 

historical patterns (for example, industrial pollution) may endanger fungus diversity and 

sporocarp production by commercial species (Arnolds 1991, Jasen and others 1985).

Managers must characterize the typical dynamics of change for their particular ecosystem and 

adopt practices that provide sufficient habitat for species to perpetually reproduce or migrate. 

For instance, Rhizopogon exiguus (a species listed in the FEMAT report [1993]) has been found 

only in late-successional forests. If, indeed, it depends on some characteristic of older forests for 

its existence, then its long-term survival depends on its ability to colonize new appropriate 

habitats when its original habitat changes. Its spores are disseminated by small mammals that 

rarely wander deep into new clearcuts, except where they can find sufficient cover from 

predation under coarse woody debris. Unless there is significant connectivity among stands of 

late-successional forest or their structural components, this fungus may eventually become 

threatened as remaining patches of old-growth forest inevitably encounter stand-replacement 

disturbance events such as fire or logging.

Ecosystem processes occur on various scales, from specific habitats to forest stands, 

landscapes, and regions. Effective ecosystem management must integrate plans or activi ties for 

a given scale with management considerations for other scales. Ecological or geographic 

boundaries rarely correspond completely with ownership, administrative, or political boundaries, 

therefore ecosystem management also must operate across these divisions.

Some species of fungi have very particular habitat needs. Oxyporus nobilissimus, for 

instance, occurs only on large-diameter trees, snags, or stumps of Abies species, especially 

Abies procera. Continual recruitment of old noble firs is needed for this fungus to persist.

Likewise, many edible ectomycorrhizal fungi flourish with particular species and ages of host 

trees. The American matsutake now fruits abundantly in shore pine (Pinus contorta var. 

contorta) stands planted 40 years ago to stabilize dunes on the Oregon Coast ,4 and Korea is 

the world's largest producer of Japanese matsutake mushrooms because it has extensive young 

pine stands that developed after the Korean war.5

4Personal communication. 1993. Dan Segotta, botanist, Oregon Dunes National Recreation Area, Siuslaw National Forest, Reedsport, 

OR 97467.

5Personal communication. 1993. Yun Wang, mycologist, Crop and Food Research, Mosgiel, New Zealand.

89

Multiple Scales
90

Similarly, Boletus mirabilis forms mycorrhizae only with hemlock (Tsuga) species, and its 

sporocarps are found growing only from thoroughly rotted wood containing hemlock roots.

At the scale of forest stands, silvicultural practices can be used to enhance fungus 

diversity. The Final Supplemental Environmental Impact Statement (FSEIS; USDA and 

USDI 1994a) that resulted from President Clinton's forest plan, designates large areas of 

Federal forest lands as "late-successional reserves." For areas within this designation that 

have been clearcut during the last four decades, the primary management goal is using 

silvicultural manipulations (for example, thinning or snag creation) to speed the 

development of late-successional structure and habitat in regenerated forest stands, and 

thereby enhancing ecosystem diversity. Several recent studies (Amaranthus and others 

1994, study 4) suggest that older forest habitats support a greater diversity of truffles and 

ectomycorrhizal morphotypes, as well as more unique species, than do adjacent young 

forest plantations. Research that examines the response of fungus communities to 

silvicultural manipulations and changing forest structure and composition will be essential 

to evaluate progress towards this goal (studies 2 and 3).

Silvicultural practices used to speed development of late-successional characteristics also 

may have implications for some commercial mushrooms. Although C. cibarius and C. 

subalbidus are commonly found in younger stands, they were placed on the FEMAT list of 

old-growth-associated species out of concern that populations occurring in old-growth 

forests may be genetically unique, and that commercial harvesting pressures might harm 

them. Cantharellus tubaeformis, on the other hand, was listed in FEMAT because it is more 

typically found in older forests, and, may be associated with coarse (large-diameter) woody 

debris that remains as a legacy from previous old forests. If this observation is verified, then 

maintaining or creating this legacy in late-successional reserves would improve its habitat. 

Likewise, increasing the amount of coarse woody debris will provide additional habitat for 

less frequently collected saprobic mushrooms such as sulfur shelf (Laetiporus sulphureus), 

lion's mane (Hericium abietis), angel's wings (Pleurotus porrigens), and Ganoderma 

species.

Some portions of Federal forests are designated as "matrix" lands, where timber 

production is emphasized. Silvicultural practices used for enhancing timber production 

typically employ clearcut harvesting timed to occur when rate of increase in mean annual 

increment of tree volume (derived from diameter and height growth) starts to decline. 

Although stands approaching harvestable age, (using this criterion) produce abundant 

quantities of commercially valuable ectomycorrhizal mushrooms and truffles, fruiting of 

these fungus species is typically negligible during early stages of stand regeneration. Areas 

managed for short timber harvest cycles will have a greater proportion of their forest stands 

in early seral stages than areas managed for longer timber rotations; therefore overall 

production of edible mycorrhizal species across a landscape or ownership may be 

diminished with short timber harvest cycles. If edible mushroom production is correlated 

with vigorous growth of host trees (young or mature), then studies of commercially thinned 

middle-aged stands may provide valuable information about sustaining high levels of 

mushroom production (studies 9 and 12) while producing timber.
91

Japanese foresters manipulate forest stands specifically to improve matsutake production 

(Tominaga 1978); they clear understory growth, reduce litter depth, and thin trees. Practices 

such as mild controlled burns or density management may improve matsutake fruiting in the 

Pacific Northwest. Changes in matsutake production may depend mainly on how litter is 

removed or thinning is conducted. Thinning intensity and pat terns, soil compaction and 

movement, and slash disposal all may have significant effects. With an understanding of 

these effects, thinning can be designed to maintain or enhance mushroom production.

On a landscape scale, Bormann and Likens (1979) describe the northern hardwood forest 

as a shifting mosaic of irregular patches, differing in composition and age, and driven by 

disturbance, growth, and decay. This seems a good way to envision most, if not all, natural 

forested landscapes, although the characteristic spatial and temporal scales of the mosaic 

will differ. The species and abundance of fungi respond to this shifting mosaic of forest 

conditions (Mehus 1986). A primary objective for managing fungi on a landscape level is to 

create (or maintain) sufficiently large and connected habitats to sustain viable populations 

of all species. Within this goal, managers also may wish to assure a steady supply of 

readily accessible habitat that produces abundant crops of edible mushrooms.

Three aspects of habitat that influence fungus communities and mushroom production are 

most relevant at the scale of landscapes: (1) different major forest types, (2) different 

successional stages within a given forest type, and (3) microhabitat diversity within each 

forest type and successional stage. Forest types, successional stages, and unique 

microhabitats harboring rare or endemic species, accommodating high fungus diversity, or 

supporting high levels of edible mushroom production need to be identified, mapped, and 

inventoried. Basic inventories are essential because they provide benchmarks for future 

comparisons and allow managers to predict how fungus communities or edible mushroom 

productivity will change overtime as the mosaic of forest conditions are manipulated.

Regional lists of rare fungi depend on identification of unique fungus species or endemic 

populations that deserve protection. During evaluations of fungus species for inclusion on 

such lists, their abundance, distribution, range, variation among populations, and local 

adaptations need to be considered.

Commercial harvest of edible fungi significantly contributes to the regional economy. 

Transient harvesters can work throughout most of the year if they follow a seasonal route 

through the Pacific Northwest, as various species fruit at different locations or elevations. 

Managers can better regulate the harvests on their own lands if they communicate 

regularly with managers in other portions of the region about timing and sizes of 

mushroom crops, harvester activities, and purchase prices.

Management activities or plans at any given scale invariably affect management 

considerations on adjacent scales. Regional listing of a rare fungus species could shift 

timber harvest away from sites having appropriate habitat for that fungus. Silvicultural 

manipulations of many individual stands will affect the mosaic of forest conditions on the 

landscape and may result in increasing or decreasing mushroom crops.
Effective ecosystem management requires coordination among landowners and regulatory 

agencies and integration of plans at different scales. For example, if public lands provide 

adequate habitat for fungi associated with late-successional forests, short-rotation timber 

management can be practiced on private forest lands with less risk of extirpating species of 

concern. On the other hand, many industrial forest landowners are closing their land to the 

public to prevent problems with fire, vandalism, and garbage dumping; hence private 

timberlands may act as reserves where edible fungi are not subject to human harvests and 

can freely disseminate spores.

In most forests, human management plays a dominant role in shaping the landscape, and 

human activities have become an integral component of ecosystem processes (for example, 

fire suppression, timber harvests, and livestock grazing.) Ecosystem management of public 

forests presents us with the challenge of obtaining human amenities in a manner that mimics 

naturally evolved patterns, thereby conserving species, interrelations, and processes that 

ensure the forest will produce a wide variety of amenities and useful products in perpetuity.

Human uses of forest ecosystems shift in response to economic conditions, technological 

advances, and changing social values; therefore, the public must be included in the planning 

process if results are to reflect current social values and economic needs. The increasing 

value that society is placing on biological diversity has prompted conservation organizations, 

such as The Nature Conservancy, to create databases of rare species and their habitats on 

private lands. Integrating databases for private lands with similar databases for public lands 

allows managers to examine species occurrence and rareness across whole ecosystems 

rather than just ownerships, thus enabling more effective, less expensive, and less restrictive 

conservation efforts. Public agencies would benefit from efforts by local mycological societies 

to extend species databases to fungi, just as native plant societies have for plants.

The recent increase in the number of people commercially harvesting edible mushrooms is 

another example of how people play a constantly changing role in ecosystems. Some of the 

increase came from forest workers who lost employment when logging was restricted on 

Federal lands to protect the northern spotted owl. Mushroom harvesting increased quickly, 

and many managers were caught unprepared; hence, newly instituted regulations and permit 

systems needed refinement. The public has provided valuable input regarding commercial 

mushroom gathering during the last several years by helping managers revise permits, 

improving the fairness and efficacy of harvest regulations, and ameliorating conflicts between 

commercial and recreational pickers. As with the harvest of any wild organism, mushroom 

collectors are concerned about sustaining the resource, and increasingly recognize the 

relation between mushroom production and appropriate forest habitats. Their input (in 

conjunction with opinions of the interested public as a whole) should be considered when 

designing how forest conditions will change across the landscape over time.

To be effective, ecosystem management must be "adaptive," that is:

• The best information currently available should be used for immediate decisions 

• Monitoring and research activities should be started to address critical areas of ignorance

• Management strategies should be adapted (modified) as improved information

 becomes available

People and 

Ecosystems

Adaptive 

Management

92
These principles have been incorporated into the survey and management guidelines 

described in the FSEIS (USDA and USDI 1994a). and adopted in the record of decision 

(USDA and USDI 1994b). The first surrey strategy is managing known sites of rare 

species. The second is surveying sites where ground-disturbing activity is anticipated. The 

third is conducting surveys of specific likely habitat for presumed rare species, and the 

fourth is conducting general regional surveys. The information acquired while implementing 

each strategy will be used to modify the others. For instance, a database of herbarium 

specimens of the FEMAT fungi has been compiled and made accessible to managers so 

that collection locations can be used to protect "known" sites of occurrence. Habitat and 

location information will be used to refine our understanding of habitat requirements for 

each species. This information can then be used to determine which species are potentially 

present in a particular area before ground-disturbing activities occur, and where to look for 

other populations. Information from the first three steps will be used to create a 

habitat-stratified sampling scheme for the general regional surveys.

A good example of the adaptive management process for edible mushrooms is the 

potential use of research on the fruiting patterns of morels in response to fire. If the timing 

and intensity of fires is related to subsequent levels of morel fruiting, managers may be 

able to reduce dangerously high fuel loads with controlled burning, while enhancing 

production of this special forest product.

Successfully implementing the principles of ecosystem management we have just 

illustrated will entail:

• Conducting relevant monitoring and research activities

• Using the best information available to develop and continuously update models for 

predicting the results of management choices

• Improving information access and transfer

• Developing regional strategies to enhance cooperation among land owners, managers, 

researchers, and the interested public

Monitoring and research are absolutely essential, but can be expensive. Managers and 

researchers must cooperate to design cost-effective monitoring and research programs 

that provide information useful for supporting management decisions. They also must 

develop technology transfer systems that disseminate research results promptly, so that 

further decisions are based on the most current information. Management and monitoring 

(including research) can be envisioned as a feedback loop with each activity continuously 

refining and improving the other. Acquiring and disseminating critical information may 

appear a daunting task, but if it is approached logically and systematically, managers will 

obtain pertinent knowledge in a timely manner.

A step-wise approach to monitoring and research activities would include the following 

elements:

• Identify subjects of critical concern and assign priorities to them

• Identify management options for addressing these concerns

• Identify information required to choose among options

93

Integrating Forest

Fungi Into Ecosystem

Management

Monitoring and 

Research
• Assess the resources available to procure needed information

• Choose creative and cost-effective methods of acquiring information

• Share the costs of data gathering with cooperators

• Assure that information becomes quickly and readily available to managers

• Verify that new information is incorporated into management activities

Researchers have developed several ways to examine fungus diversity and sporocarp 

production (Arnolds 1992, Vogt and others 1992), but these procedures have not been adapted 

to regional biodiversity surveys or edible mushroom monitoring projects in the United States. 

Standardized protocols for measuring and monitoring fungi will ensure compatibility of data sets 

for comparison and evaluation. They must be sufficiently broad to accommodate differences 

among fungus species and the specific goals of a survey, monitoring, or research project.

National Forest managers must implement the selected protocols on a large scale to meet survey 

strategies 2, 3, and 4 of the record of decision (USDA and USDI 1994b). In addition to the 

standardized protocols being development by the U.S. Department of Agriculture, Forest Service, 

Pacific Northwest Research Station, national efforts are also underway. A book is expected to be 

published by the National Biological Survey and the National Museum of Natural History on how 

to collect samples, culture isolates, and monitor diversity of fungi from terrestrial and aquatic 

substrates.6 Rather than concentrate on particular taxa, the book will be divided into five major 

sections: (1) macrofungi on soil, wood, leaves, lichens, and other substrates; (2) readily culturable 

microfungi; (3) fungi associated with animals; (4) aquatic fungi and protoctistan organisms 

formerly treated as fungi; and (5) general topics–for example, herbarium management, culture 

collections, database management, and appropriate molecular techniques. Each section will 

feature a complete range of sampling protocols for each fungus group.

These protocols will provide essential tools for environmental assessments of fungi on public 

lands in the range of the northern spotted owl. Protocols will be tested by field personnel and 

evaluated by land managers for feasibility and cost. Because nonspecialists often implement the 

fungus survey protocols (at least portions that do not require taxonomic expertise), the protocols 

will thoroughly describe unique aspects of assessing fungus populations. Prior training of field 

personnel will be requisite.

The mycology team at the USDA Forest Service, Pacific Northwest Research Station, in 

Corvallis, Oregon, is currently developing practical field procedures that can be used by 

managers for monitoring the production of edible mushroom sporocarps. These procedures are a 

subset of the sampling protocols for fungus diversity; they concentrate on a single fungus species 

and management considerations regarding sporocarp harvests. Special emphasis will be placed 

on practical, economical, valid methodology

6 Draft title: "Standard methods for fungi" as a volume in the "Measuring and Monitoring Biological Diversity Series" being published by the 

National Biological Survey and the National Museum of Natural History. Editors are Greg Mueller, Field Museum of Natural History, 

Chicago, IL 60605; Gerald Bills, Merck Research Laboratories, Rahway, NY 07065; Amy Ros sman, Systematic Botany and Mycology 

Laboratory, Beltsville, MD 20705; and Harold Burdsall, U.S. Department of Agriculture, Forest Service, Center for Forest Mycology, 

Madison, WI 53705.

94
usable by nonspecialists to implement monitoring programs wherever 

commercial harvesting of wild mushrooms is a significant activity.

Managers and researchers need to cultivate a clear understanding of each other's 

needs and goals if they are to develop useful monitoring and research plans. Managers can be frustrated by lack of precise information when they need to make decisions, 

and scientists often perceive a lack of appreciation among managers for the rigor of 

the scientific method. Managers and researchers will fully realize the limitations and 

opportunities each faces only by cooperating to achieve mutual objectives. Constraints 

are commonly inherent in funding mechanisms or institutional goals, and these barriers 

to shared endeavors must be altered to allow effective cooperation. The conference 

that this publication summarizes was specifically intended to bring together managers 

and researchers to develop an integrated approach to monitoring and managing fungi 

in forest ecosystems.

Researchers and managers must cooperate in developing models that theoretically,

mathematically, and geographically predict ecosystem responses to the management 

choices. Mycologists and other researchers should be involved in the early stages of 

modeling the role of fungi in forest ecosystems, because they have the greatest 

familiarity with distributions, habitat requirements, reproductive mechanisms, and life 

histories of important fungus species, as well as their functional roles in the ecosystem 

and interrelations with other biotic and abiotic components. The theoretical exercise of 

developing models for the occurrence, persistence, and function of fungi in forests 

provides useful insights about additionally needed data, how important the missing 

information is, and how readily it may be acquired. This information allows us to design 

the most useful monitoring and research programs for improving the predictive power 

of our models.

Because fungi are so numerous and ecologically diverse, monitoring and managing 

them species by species is impractical in many cases. Effective use of new models and 

technologies for implementing ecosystem management must be tied to evolving 

concepts of preserving adequate representative habitats (continuously over time) for 

the long-term viability of all species, including those beyond our ability to specifically 

consider (Marcot and others 1994). The challenge in this case, is defining what constitutes "adequate representative habitats." The first step in modeling the relations 

between fungi and habitats is developing conceptual models that postulate how groups 

of fungus species (guilds) with similar ecosystem functions or life histories are related 

to various habitats or their components. Conducting regional surveys over an extended 

period is the next step in identifying species or guilds that indicate adequate habitat for 

a large number of associated species. The third step is evaluating how species with 

similar reproductive mechanisms will respond to various forest management regimes. 

The final step is developing predictive models to quantify how indicator species and 

guilds of fungi will respond to anticipated changes in the landscape mosaic of forest 

habitats. The authors are not aware of any examples where this has been attempted 

with fungi, so this endeavor will be challenging.

Modeling may be applied to specific rare fungi as well. Those listed in the FEMAT 

95

Modeling
Geographic Information System (GIS) map layers will help identify locations with 

especially rare habitat, reveal the status of connectivity among habitats, and suggest 

opportunities for creating appropriate habitat (for example, structural components) in 

other areas.

Habitat modeling of fungus diversity or rare species occurrence is only in the early 

conceptual stages; substantial work (regional monitoring and empirical studies) is 

needed to develop and test useful predictive relations for our models. Nevertheless, 

conceptual models will be useful for inferring unusual, significant, or rare habitats in 

greatest need of short-term protection and assigning priorities to needed research.

Predictive models that relate edible mushroom productivity to habitat factors will allow 

managers to assess how planned forest management activities influence mushroom 

crops and may suggest means for enhancing mushroom production. Salient habitat 

factors that can be manipulated include tree species, plant communities, stand age, 

stand density and structure, abundance of coarse woody debris, fire frequency, and 

soil compaction, movement, or drainage. Although some important habitat factors are 

not readily altered (for example, aspect, climate, or soil type), managers can chose to 

encourage fruiting in accessible locations where mushroom production is most likely to 

improve in response to management activities.

On a larger scale, if mushroom production per unit area can be correlated with stand 

characteristics, such as tree species, age, or structure, then different management 

regimes and objectives (with their associated silvicultural assumptions) could be used 

to create scenarios of mushroom productivity across watersheds, forest, or regions.

Although new monitoring programs will be essential for ongoing adaptive management 

plans, much useful information on edible fungi already exists, and references are being 

compiled for fungi listed in the FEMAT report (1993). A logical first step is summarizing 

current information from diverse or obscure sources and making it available in a 

convenient form. The next step is using every means available, especially new information-transfer technologies, to provide easy and quick access to summarized knowledge and new monitoring or research information.

Unlike plants and many groups of animals, no complete guide to the macrofungi of the 

Pacific Northwest currently exists, and many genera of fungi still lack definitive monographs and keys. Even when comprehensive treatments exist, they often need revision. Even so, several good identification books are available. Where descriptions are 

lacking for rare fungi, researchers should give high priority to publishing useful descriptions and keys.

Mycologists have been collecting Pacific Northwest fungi as specimens for herbaria for 

nearly a century. Herbarium archivists are presently converting huge datasets from 

note cards or data books to electronic format. This is a slow, tedious, underfunded 

process that will take years to complete, but it has been expedited for FEMAT-listed 

fungi. Recent Federally funded contracts have supported visits by taxonomic experts to 

significant herbaria where specimens were verified and collection data electronically 

Information Access

96
97

remote locations to acquire information about specimens of interest. As with the FEMAT 

species, specimen identification should be verified and information recorded in a 

standardized format.

The procedure for extending surveys of fungus diversity beyond herbarium records also 

can benefit from past efforts and experiences. For instance, cataloging rare vascular 

plant species, locating their populations, and preserving their habitats began nearly 15 

years ago in Oregon (Meinke 1982). The experiences and ideas of individuals and 

organizations (for example, State Natural Heritage programs, The Nature Conservancy) 

with experience in this process will be invaluable for designing and conducting efficient 

fungus surveys.

Useful information is available for important species of wild edible fungi, but few efforts 

have been made to synthesize knowledge from diverse sources, especially as they relate 

to forest habitats and management. Molina and others (1993) summarize information 

concerning the harvest of commercially valuable, wild, edible species in the Pacific 

Northwest. In cooperation with experts on each species, a series of more detailed 

publications is in progress, each summarizing current knowledge about a given species 

of commercial importance (for example, matsutake, chanterelles, and morels).

Managers struggling to regulate the rapid increase in commercial harvesting of mushrooms can find a comparable precedent in the brief, but intense, harvest of Pacific yew 

(Taxus brevifolia Nutt.) bark for taxol production (Campbell 1993, Hartzell 1991). Th e 

rapid development of yew biomass as a special forest product and concerns about its 

sustainability are in many ways analogous to the development of mushrooms as special 

forest products. Mushrooms have been used medicinally in Asia for millennia (Stamets 

1993), and if active ingredients are isolated from fungi and proven effective by 

pharmaceutical companies, new species of wild fungi may suddenly experience intense 

harvest pressure in their native habitats. Managers will benefit from familiarity with 

previous examples of urgently-needed harvest regulations.

In addition to synthesizing current knowledge and learning from past experiences, 

effective ecosystem management of forest fungi must use the full array of new technologies now available for handling large quantities of information. The recent increase in 

electronic communication capabilities and software, especially the Internet, will transform 

the accessibility and utility of information. Large databases of recent literature citations 

are already available on-line from most universities. Electronic mail allows virtually 

instantaneous global communication among colleagues. Bulletin boards provide 

interactive discussions on almost any topic of mutual interest. Recent developments in 

World Wide Web browsing programs allow keyword searches of international resource 

indices that direct the user to "home-page" sites (providers) that maintain and 

continuously update pertinent information for public access and use. Advances in 

personal computer hardware, increases in data transmission rates, and standardizing of 

data transfer protocols are expanding our ability to share information, especially images. 

Individuals or organizations with specialized knowledge will be able to provide on-line 

resources that support interactive inquiries.

Advances in computer science also provide managers with several ways to model 

ecosystems. The GIS databases are powerful tools for applying model predictions to
98

decisions about changing forest landscapes; for example, creating electronic databases of 

pertinent collections of fungi in herbaria was the essential first step for implementing new 

survey plans on Federal lands. Placing appropriate location information on shared GIS 

databases will allow managers to determine if herbarium specimens of significant fungi have 

been collected from lands they manage, and evaluate the precision of relevant location 

information. If location data are vague or the sites have been disturbed since the specimens 

were collected, the sites should be revisited. Satellite trilateration using the Global Positioning 

System (GPS) can record the precise location of newly discovered populations or habitats on a 

GIS data layer so that future activities will account for their presence.

Organizations conducting diversity assessments of fungi will likely benefit from the 

development of on-line mushroom identification services. Either dichotomous or synoptic keys 

could be accessed electronically and designed for easy use. Users could point and click on 

images of key features to clarify their choices. Synoptic keys use a set of shared characteristics 

described for each taxon, and the combination of selected characters narrows the alternatives 

to appropriate taxa. Synoptic keys are most efficient when all selected characteristics are 

described for each taxon in the key, and some subset of characteristics is unique for each 

taxon. Dichotomous keys also can incorporate a "point-and-click-to-learn-more" format 

incorporating illustrations of mushroom characteristics, glossaries, common and scientific name 

indices, and color images. This technology has the potential to make mushroom identification 

entertaining as well as educational.

The FEMAT report (1993) and subsequent documents implementing its analysis (USDA and 

USDI 1994a, 1994b) were pivotal initiatives for instituting ecosystem management on Federal 

forests in the Pacific Northwest and incorporating fungi in the process. These initiatives should 

be considered the beginning of efforts to fully survey, monitor, manage, and sustain fungus 

diversity and edible mushroom harvests throughout the region on all land ownerships. Progress 

towards this goal will be augmented if managers and the mycological community cooperate to 

develop regional strategies that:

• Expand the level of mycological expertise

• Involve the public in the process of ecosystem management

• Coordinate the efforts of all interested parties

Ecosystem management and assessments of biological diversity will be possible only if we can 

identify the organisms comprising the web of life. Several approaches are needed to alleviate 

the current and anticipated shortage of professional mycologists trained in taxonomy. 

Universities and funding agencies should support more graduate programs and students in this 

fundamental science and hire them when they graduate. The recent announcement of the 

"Partnership for Enhancing Expertise in Taxonomy" by the National Science Foundation strongly 

supports this effort.

Training of individuals with strong mushroom identification skills is needed as well. Many 

Federal land management agencies have staff botanists who are assigned management of 

fungi as yet another responsibility. Most botanists have training in the principles of taxonomy 

and use of taxonomic keys, but some are unfamiliar with the

Regional 

Strategies
vocabulary used to describe the characteristics of fungi. Agency botanists commonly 

express interest in learning more about mushroom identification, and would benefit from 

training programs sponsored by experts. One such program is the 2-day "Mushrooms and 

Managers" short course sponsored by the Oregon State University College of Forestry and 

the Pacific Northwest Research Station. Another approach would be a "mycological 

institute" similar to the "silvicultural institute" held periodically at Oregon State University. 

Institute training could provide an intensive 1- or 2-week, hands-on session with specific 

training in mushroom identification and field sampling protocols. Much of the course could 

be taught by invited specialists.

In most parts of the country, and especially the Pacific Northwest, many people have a 

strong interest in macrofungi; they form the membership of numerous mushroom clubs and 

mycological societies. Although most members became interested in macrofungi as a source 

of food and recreation, some have expanded their interests into more technical aspects of 

mycology and have the interest, time, and technical knowledge to help with research. 

Examples of their efforts include the landmark chanterelle project by the Oregon Mycological 

Society (study 8) that includes identification of all mushrooms at a site in the Mount Hood 

National Forest, the extensive survey of fungi at Barlow Pass, Washington, conducted by 

members of the Puget Sound Mycological Society in cooperation with several research 

mycologists (Ammirati and others 1994), and the long-term research contributions of the 

North American Truffling Society (Rawlingson and others 1995). The Pacific Northwest Key 

Council provides a forum for amateur mycologists with a scientific bent to hone their skills in 

taxonomy; however, only a few dozen people in the region have sufficient time, interest, and 

knowledge of macrofungi to participate effectively in sampling fungus diversity. It is 

unrealistic to think that the mushroom club closest to a given National Forest district or other 

administrative unit harbors the expertise to conduct complex inventories or identification 

tasks. Most clubs have limited funds for libraries and microscopes, and the majority of club 

members are not experienced in using technical literature and microscopic features of 

macrofungi to make definitive identifications. Nevertheless, if the skills, resources, and 

commitment of local volunteers is carefully assessed, managers and researchers can usually 

find appropriate ways to use their help. Certainly, when talented mycologists do volunteer, 

every effort should be made to support their participation.

Commercial mushroom harvesters are another group with extensive experience. Their 

knowledge of ideal habitat for abundant fruiting of edible mushrooms is probably unequaled. 

They also are skilled at reading marks or signs in the forest indicating mushroom 

consumption by animals or collection by other humans. Although often secretive and wary of 

land managers, many commercial harvesters are keenly interested in learning more about 

the mushrooms they collect, and support efforts to ensure the sustainability of the resource. 

Managers and researchers benefit greatly from soliciting their cooperation in designing, 

conducting, and evaluating edible mushroom monitoring projects.

Like "ecosystem management," "coordination" and "cooperation" are often considered 

good-sounding buzzwords infrequently put into practice. Several examples, however, 

should demonstrate their applicability to the study of fungi.

99

Coordination
100

We noted earlier that no complete publication currently identifies all the macrofungi in 

the Pacific Northwest (that is, a "mycota" similar to a “fora" for plants). Even if taxonomists reach agreement on species distinctions, ample work remains to describe each 

species and provide keys for each genus. Publication of a complete mycota for the 

region might be delayed for decades while issues are resolved and identifications 

completed or updated. The advent of on-line references provides another alternative. 

An extensive (not necessarily complete) mycota would still involve considerable 

cooperation among taxonomic experts worldwide, as well as significant institutional and 

financial support; but on-line keys, descriptions, references, and citations can be 

continuously updated, gaps noted, and unresolved issues explained. Given sufficient 

enticement, interested parties could begin cooperating immediately to design and 

implement this resource.

Studies that examine fungi and their responses to forest management activities 

throughout the range of relevant habitats constitute another endeavor that significantly 

benefits from coordination. Regional research may initially be more expensive than 

local case studies, but the broad applicability of the results provides significant savings 

in the long run. Mixed ownership of forest lands in the Pacific Northwest lends itself 

readily to regional studies that involve cooperative investigations among organizations 

with different interests and management goals. Mushroom fruiting is so variable that 

long-term monitoring is necessary to gather meaningful data. Regional investigations 

conducted by several collaborators are more likely to be maintained for extended 

periods than local case studies because more organizations have a stake in their 

continuity.

Successful surveys of fungus diversity and studies of edible fungi will inevitably require 

open communication and cooperation from a wide range of forest owners, managers, 

scientists, resource specialists, mycological societies, and harvesters.

The "fungophobic" cultural tradition our society inherited from British immigrants (Arora 

1986) induces many managers to disregard fungi and evokes derogatory opinions from 

others. Although fungi have been recognized as belonging to a separate taxonomic 

"kingdom" of life for over 20 years, many people still consider them plants. Mycologists 

are often hired as botanists. These examples illustrate the difficulties mycologists and 

mushroom enthusiasts face in obtaining resources to manage our forests for more than 

just the trees. As concepts of forest management evolve, however, ecosystem management is becoming a reality. Fungi play such vital roles in forest ecosystems that 

they cannot be ignored in management plans, yet resources available for monitoring 

fungi are likely to remain limited. Meeting the challenge of doing more with less 

requires managers and mycologists to pursue creative options for investigating and 

managing forest fungi in an ecosystem context.

Ecosystem management of forest fungi will require hard work, patience, new technologies, innovative solutions, extensive cooperation, and shared resources, but the 

elements of success are in place. Given the enthusiasm, excitement, and optimism 

common among mycologists, mushroom lovers, and ecosystem managers, we can 

Closing Remarks
101

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103
Acknowledgments

The excellent technical reviews by Joseph Ammirati, Shannon Berch, Eric Danell, Paul Dunn, and 

James Trappe are gratefully acknowledged. We thank Doni McKay and Thomas Danner for help with 

keyboarding. Artwork for the cover was done by Christine Roberts. The conference and proceedings 

were supported by the Cascade Center for Ecosystem Management, PNW Ecological Framework for 

Management Program, and the Northwest Forest Plan.

104
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Nation's forest resources for sustained yields of wood, water, 

forage, wildlife, and recreation. Through forestry research, 

cooperation with the States and private forest owners, and 

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