A Regional Research and Monitoring Program for Commercially - Harvested Edible Forest Mushrooms
David Pilz and Randy Molina
Pacific Northwest Research Station
US Department of Agriculture, Forest Service

Cantharellus formosus  
"Pacific golden chanterelle"
Tricholoma magnivelare  
"American matsutake"
Morchella species  
"Black morel"
Boletus edulis  
"King bolete"


Issues and Concerns

The forests of the Pacific Northwest are rich with diverse fungi and abundant edible mushrooms.  During the last decade, forest managers have expanded their appreciation of this resource as they begin to grapple with the twin issues of rare fungi associated with decreased old-growth forest habitat and edible mushrooms that are commercially collected in large quantities.   Both issues are especially important on public forests managed by the Forest Service (US Department of Agriculture) and Bureau of Land Management (US Department of Interior).  Federal lands encompass a large proportion of forest mushroom habitat in the Pacific Northwest, and these agencies are mandated to conserve biological (fungus) diversity and provide opportunities for the sustainable harvest of commercial products (edible mushrooms).  Early efforts to address these issues are summarized in "Managing forest ecosystems to conserve fungus diversity and sustain wild mushroom harvests"  (Pilz and Molina, 1996), a free General Technical Report (PNW-GTR-371) published by the Pacific Northwest Research Station.

Air pollution and intensive forest management (leading to declines in forest health and simplified forest ecosystems) are thought to be major contributors to decreased mushroom diversity and productivity in Europe (Arnolds 1991).  In the Pacific Northwest, climate change, pollution from growing urban areas, ozone depletion, introduced pathogens, and intensive timber harvesting may also be detrimental to forest health and thus impact edible mushroom production.  Initial studies of the impacts of edible mushroom picking have concluded that careful harvesting does not diminish subsequent fruiting (Egli and others 1990, Norvell and others 1995), but these small-scale studies have not adequately addressed the impacts of large-scale commercial mushroom harvesting or forest management activities over long periods of time.

We propose a regional approach to edible forest mushroom monitoring and research in the Pacific Northwest (and potentially elsewhere) that is designed to be systematic, statistically sound, modular, and voluntary.  Cooperation among landowners, forest managers, scientists and interested publics (for instance, mycological societies and commercial mushroom harvesters) will be integral to its success.

Baskets of commercially-harvested wild edible forest mushrooms ready for sale at local buying stands

Program Rationale

-  The Pacific Northwest region of the North American continent is one of the best places for conserving genetically diverse populations of temperate coniferous forest fungi because:

-  The USDA Forest Service and USDI Bureau of Land Management have begun implementing regional monitoring programs for rare fungi associated with old-growth forest habitat, but no comparable regional monitoring of edible mushrooms yet exists.  Commercial harvest of edible forest mushrooms is now a large, wide-spread,  regional industry, but current site-specific research and monitoring projects are inadequate to ensure sustainable harvesting throughout the region.

-  Factors that have lead to declines in edible forest mushroom production elsewhere are starting to impact forests in the Pacific Northwest; hence regional trends in fruiting of edible ectomycorrhizal mushrooms may indicate shifting mycorrhizal relations and associated changes in forest health.

-  Maintaining or enhancing appropriate habitat is the most important factor in guaranteeing the viability of fungus populations and providing future opportunities for sustainable harvest of edible mushrooms.   Forest types and age classes will shift across the landscape in the coming decades and centuries as a result of natural disturbances and forest management activities.   In order to maintain connectivity of habitat for reproductive dispersal and provide continuously available harvest opportunities for the public, edible mushroom occurrence and production must be quantified in various ecological habitats and stand conditions. This information must then be incorporated into long-range ecosystem management plans.

-  A regional research and monitoring program is cost-effective because it shares work and expense among cooperators, avoids unnecessary duplication of field sampling, and allows landscape or regional inferences about noted fruiting trends, habitat correlations, or forest management activities.

-  Public participation in program design and field sampling will lower agency costs, improve understanding of monitoring goals and methods, enhance communication between public land management agencies and user groups, and increase confidence in the results.

 Program Objectives

-  Low-intensity, long-term monitoring of areas with heavy commercial harvesting to ensure harvest sustainability and evaluate reasons for potential trends.

-  Low-intensity, long-term monitoring of natural areas (where neither timber nor mushroom harvesting occurs) to provide control sites for interpreting trends in commercially harvested areas and to detect trends related to regional changes in the environment or forest health.

-  Intensive, short-term research on correlations between mushroom productivity, habitat, and stand management activities to provide forest managers with the information needed to ensure future habitat availability and mushroom collection opportunities.

-  Use development of this research and monitoring program as a prototype for cost-effectively ensuring the sustainable harvest of an array of other nontimber forest products by engaging interested publics in research and monitoring activities.

Sampling Challenges

Ectomycorrhizal mushrooms fruit in clusters and several flushes may occur during a season.  Hence, to obtain reasonably precise estimates of edible mushroom production on a site, areas 0.4 ha (1 acre) or greater must be repeatedly sampled during the course of a fruiting season.  Long, narrow strip plots (transects) have several practical advantages over circular or square plots, especially in brushy terrain.  Hidden mushrooms are more readily found (detection error is reduced) when two individuals search from opposite sides of the plot.  Soil and vegetation trampling that results from repeated sampling during a season is lessened by spreading the impact linearly and, if the plots are 2 meters wide or less, personnel can avoid walking on the plots entirely.   Field personnel also find it easier to remember where they have already searched in linear plots than in large circular or square plots.

Taxonomic Challenges

Although most edible mushrooms are easily recognized, life histories and species concepts may still pose some challenges to monitoring program design.    For instance, several types of morels are commercially collected in the Pacific Northwest and their taxonomic identities are not yet fully resolved.  Recent evidence suggests some may be facultatively mycorrhizal and fruit regularly in non-disturbed forests, while others are likely saprobic and fruit in flushes following disturbances such as fire or logging.  Likewise, several species of chanterelles are commercially collected in the region, but their taxonomic identities are still being genetically examined.  Voucher specimens from monitoring sites will allow productivity values to be linked with emerging species distinctions and corresponding ecological adaptations.

Program Design

 Other Commercially Harvested Species

Many other species of edible mushrooms are commercially collected in the Pacific Northwest, and the number is increasing as customers become more informed and adventurous.  Monitoring less commonly collected species will depend on the willingness of interested individuals, organizations, and landowners to invest the time, money and effort.  The voluntary and modular nature of the proposed monitoring program will accomodate species of interest to cooperators.
Hydnum repandum  
Tuber gibbosum and 
Leucangium carthusianum  
“Oregon white and black truffles”
Hypomyces lactifluorum  
parasitizing Russula species  
“Lobster mushroom”


Potential Cooperators

Scientists:  PNW Research Station (Project design and implementation, training, data management, scientific analyses, and reports.)

Land Managers: USDA  and USDI.  Also any public or private forest landowner with appropriate sites and interest in the project.  (Provide the majority of field sites and personnel managers.  Collect field data.)

Public: Mycology clubs, commercial harvesters, and other interested individuals or organizations (Input on project design, periodic critique of program, collecting field data.)

While the envisioned monitoring program is ambitious and entails many challenges, our greatest asset is the large community of mushroom lovers that have a deep appreciation for fungi.  The development of this program will rely on their enthusiasm, hence we are optimistic about its success.


Arnolds, E. 1991. Decline of ectomycorrhizal fungi in Europe. Agriculture, Ecosystems and Environment. 35: 209-244.

Egli, S.; Ayer F.; Chatelain, F. 1990. Der Einfluss des Pilzsammelns auf die Pilzflora. Mycologia Helvetica. 3(4): 417-428.

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.

Pilz, D.; Molina, R.  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.

For Further Information


Related Online Posters

Commercially-Harvested Edible Forest Mushrooms: Productivity and Sustainable Harvest Research in the Pacific Northwest

Chanterelle mushroom productivity responses to young stand thinning