David Pilz

Commercial harvests of edible mushrooms from the forests of the Pacific Northwest United States: issues, management, and monitoring for sustainability

Abstract Widespread commercial harvesting of wild edible mushrooms from the forests of the Pacific Northwest United States (PNW-US) began 10–15 years ago. A large proportion of suitable forest habitat in this region is managed by the Forest Service (US Department of Agriculture) and Bureau of Land Management (US Department of the Interior). These lands are managed under an ecosystem management philosophy that entails multiple-use, sustainable forest product harvesting, resource monitoring, public participation in forest management issues, and holistic planning. Managing the harvest of edible mushrooms engages every aspect of this management philosophy. We examine a variety of issues raised by mushroom harvesting and how these issues interact with forest ecosystem management choices. We discuss regulations currently being used by managers to conserve the mushroom resource while further information is gathered, unique challenges and considerations inherent to sampling fungi, and current research and monitoring activities in the Pacific Northwest. Although current scientific evidence suggests that harvesting likely will not harm the resource in the short term, no statistically-based monitoring information exists about the cumulative impacts of intensive and widespread commercial harvesting over long-time periods. We outline a three pronged approach to long-term monitoring of the resource: (1) tracking harvest quantities in areas with intense commercial harvests; (2) sampling productivity in areas with no mushroom or timber harvests; and (3) conducting research to model the relations between forest management and mushroom productivity. Public participation and a broad collaboration among public land management agencies, private forest landowners, forest managers, researchers, and research organizations will make this approach cost effective and the results widely applicable.

Allelopathic effects of litter on the growth and colonization of mycorrhizal fungi

In laboratory studies, water-soluble extracts of the litter of four shrub and three conifer species had variable effects on the growth of four species of ectomycorrhizal fungi. In general, low concentrations (parts per thousand) stimulated fungal growth; while, high concentrations (parts per hundred and parts per ten) either stimulated growth, inhibited growth, or had no effect, depending on both fungal and litter species. In greenhouse studies, litter applied to the surface of a sand-soil mixture reduced the formation ofRhizopogon sp. on Douglas-fir seedlings. Allelochemicals in the litter may inhibit seedling growth and suppress fungai growth and root colonization in the field, thus explaining the failures of reforestation by conifer species in disturbed sites.

Diversity, ecology, and conservation of truffle fungi in forests of the Pacific Northwest

Forests of the Pacific Northwest have been an epicenter for the evolution of truffle fungi with over 350 truffle species and 55 genera currently identified. Truffle fungi develop their reproductive fruit-bodies typically belowground, so they are harder to find and study than mushrooms that fruit aboveground. Nevertheless, over the last five decades, the Corvallis Forest Mycology program of the Pacific Northwest Research Station has amassed unprecedented knowledge on the diversity and ecology of truffles in the region. Truffle fungi form mycorrhizal symbioses that benefit the growth and survival of many tree and understory plants. Truffle fruit-bodies serve as a major food souce for many forest-dwelling mammals. A few truffle species are commercially harvested for gourmet consumption in regional restaurants. This publication explores the biology and ecology of truffle fungi in the Pacific Northwest, their importance in forest ecosystems, and effects of various silvicultural practices on sustaining truffle populations. General management principles and considerations to sustain this valuable fungal resource are provided.

Fungal Conservation: Conservation and management of forest fungi in the Pacific Northwestern United States: an integrated ecosystem approach

The vast forests of the Pacific Northwest region of the United States, an area outlined by the states of Oregon, Washington, and Idaho, are well known for their rich diversity of macrofungi. The forests are dominated by trees in the Pinaceae with about 20 species in the genera Abies, Larix, Picea, Pinus, Pseudotsuga, and Tsuga. All form ectomycorrhizas with fungi in the Basidiomycota, Ascomycota, and a few Zygomycota. Other ectomycorrhizal genera include Alnus, Arbutus, Arctostaphylos, Castinopsis, Corylus, Lithocarpus, Populus, Quercus, and Salix, often occurring as understorey or early-successional trees. Ectomycorrhizal fungi number in the thousands; as many as 2000 species associate with widespread dominant trees such as Douglas-fir (Pseudotsuga menziesii) (Trappe, 1977). The Pacific Northwest region also contains various ecozones on diverse soil types that range from extremely wet coastal forests to xeric interior forests, found at elevations from sea level to timber line at 2000 to 3000 metres. The combination of diverse ectomycorrhizal host trees inhabiting steep environmental and physical gradients has yielded perhaps the richest forest mycota of any temperate forest zone. When the large number of ectomycorrhizal species is added to the diverse array of saprotrophic and pathogenic fungi, the overall diversity of macrofungi becomes truly staggering. Issues relating to conservation and management of forest fungi in the

Seedling growth and mycorrhizal formation in clearcut and adjacent, undisturbed soils in montana: A green-house bioassay

Abstract In a series of greenhouse bioassays, tree seedling growth and root-tip development were compared among soils from two areas that had been clearcut and site prepared 16 years earlier and adjacent, undisturbed forest. Seedlings grown in soil from logged areas were shorter and had fewer root tips than those grown in undisturbed forest soil; however, effects on seedling weights were not consistent among species or experimental series. Fertilizing with nitrogen eliminated size differences due to soil source. In Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco], the only species tested in sterilized soils, sterilization of logged soils resulted in increased seedling size and root-tip formation, whereas sterilization of unlogged soils had either no or a negative effect.

Compatible Management of Understory Forest Resources and Timber

Many native mosses, lichens, ferns, herbs, shrubs, and fungi are harvested by humans from the understories of Pacific Northwest forests. These understory products are used personally and commercially for decorative, culinary, medicinal, cultural and educational purposes. Understory species harvested for any of these purposes are typically and awkwardly referred to as nontimber or special forest products (Vance et al. 2001, IFCAE 2002, Table 1). Hereafter, we refer to these species simply as understory forest resources and understory products. These species have important ecological roles in forest communities. They contribute to biological diversity and long-term ecosystem productivity (Alaback and Herman 1988, Halpern and Spies 1995), underpin mammalian and avian abundance (Morrison 1982, Carey 1995, Carey and Johnson 1995) and are important aesthetic components of forests.

Productivity and Sustainable Harvest of Edible Forest Mushrooms

Summary The commercial harvest of wild edible forest mushrooms has increased dramatically in the Pacific Northwest United States during the last decade, creating public and managerial concerns about potential over-harvesting. These concerns have prompted Federal land m anagement agencies and research organizations to undertake a variety of research projects addressing the ecological impacts and long-term sustainability of widespread harvesting. This article lists and briefly describes 25 ongoing research projects investigating the three most important forest mushroom genera of commerce; matsutake, morels, and chanterelles. We finish by describing future Federal directions in regional research and monitoring designed to ensure sustainable harvests through long-term cooperative monitoring involving multiple stakeholders, especially interested publics.