Management Experiments for HighElevation Agroforestry Systems

Jointly Producing Matsutake

Mushrooms and High-Quality

Timber in the Cascade Range

of Southern Oregon

James F. Weigand

United States

Department of

Agriculture

Forest Service

Pacific Northwest

Research Station

General Technical

Report

PNW-GTR-424

July 1998
Author JAMES F. WEIGAND is a forester, Forestry Sciences Laboratory, P.O. Box 3890,

Portland, OR 97208-3890.
Abstract Weigand, James F. 1998. Management experiments for high-elevation agroforestry

systems jointly producing matsutake mushrooms and high-quality timber in the

Cascade Range of southern Oregon. Gen. Tech. Rep. PNW-GTR-424. Portland,

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

Station. 42 p.

Experimental prescriptions compare agroforestry systems designed to increase

financial returns from high-elevation stands in the southern Oregon Cascade Range.

The prescriptions emphasize alternative approaches for joint production of North

American matsutake mushrooms (also known as North American pine mushrooms;

Tricholoma magnivelare) and high-quality timber. Other agroforestry byproducts

from the system are ornamental conifer boughs, pine cones, and Christmas trees.

Management practices concentrate on increasing the physiological efficiency and

vigor of trees, and on altering leaf area index, tree species composition, and stand

age-class structure to increase matsutake reproduction. Programs of thinning and

branch pruning test regulating flows of energy and moisture to mushroom mycelia

in the upper soil. Experimental prescriptions incorporate monitoring to evaluate

ecosystem responses to management and to accelerate adaptive learning.

Key words: Tricholoma magnivelare, agroforestry systems, nontimber forest products,

adaptive management, Abies magnifica, Tsuga mertensiana, Pinus contorta, Pinus

monticola, Abies amabilis, tree pruning.
Contents 1 Introduction

1 Physical Environment

1 Location and Topography

2 Soils

2 Climate

2 Vegetation

3 Key Management Concerns

5 Management Experiments

7 Management Objectives And Goals

8 Experimental Treatment Strategies

8 Adhere to Societal and Ecological Constraints

8 Reduce Tree Pathogens

9 Reduce Pacific Silver Fir and Increase Western White Pine

9 Thin and Prune

10 Harvest Nontimber Forest Products Opportunistically

12 Management Design

15 Vegetation Patterns

16 Experimental Management: Stand 355

16 Outline of Prescription Variables

21 Experimental Management: Stand 357

21 Outline of Prescription Variables

26 Experimental Management: Stand 401

27 Outline of Prescription Variables

31 Monitoring Response Variables

33 Opportunistic Research

33 Conclusion

33 Acknowledgments

34 Literature Cited

38 Appendix 1: Management Practices, Prescriptions 1-3, Stand 355

40 Appendix 2: Management Practices, Prescriptions 1-3, Stand 357

40 Appendix 3: Management Practices, Prescriptions 1-3, Stand 401

42 Appendix 4: Computer Source Code For Management Regimes
Introduction Growth in the international trade in North American matsutake mushrooms

(Tricholoma magnivelare (Peck) Redhead) from forests in the Pacific Northwest

to markets in Japan (Weigand 1997) has prompted forest managers to consider

silvicultural practices that increase commercial production of matsutake mushrooms.

Interest in this new source of forest revenue comes at a time when publicly owned

forests are subject to greater timber harvest constraints, and timber revenues are

lower than in previous decades. One obstacle to increasing matsutake mushroom

production is the absence of a tradition of matsutake mushroom management in

North America. By contrast, matsutake mushrooms of the closely related species

T. matsutake have been managed for centuries in eastern Asia (Hosford and others

1997, Totman 1989). Agroforestry technology developed for matsutake mushroom

culture in Japanese, Korean, and Chinese forests may be useful in several North

American forest types, particularly forests comprised of lodgepole pine (Pinus

contorta Dougl. ex Loud.; Pilz and others 1996b), jack pine (P. banksiana Lamb.;

Miron 1994), and ocote pine (P. ocote; Villarreal 1993).

A network of matsutake mushroom management areas has been established in

Washington and Oregon to study the ecology and productivity of matsutake mushrooms (Hosford and others 1997). Sites represent a broad spectrum of habitats

from sea level to 1800 meters in elevation. Wide distribution over many climate

and vegetation zones suggests that matsutake mushrooms may have evolved

different physiological responses to local conditions. An important zone of high

natural productivity and concentrated commercial harvest of matsutake mushrooms

straddles high-elevation forests on both east and west slopes of the Cascade Range

in southern Oregon. The region is noteworthy for its harsh climate, volcanic activity,

ash and pumice soils, and low tree growth (Hobbs and others 1992). Knowledge of

the site-specific autecology of matsutake mushrooms, however, remains fragmentary.

This report focuses on incorporating experimental design into stand prescriptions

that combine timber management and matsutake mushroom culture. Designing

easy-to-execute experiments within management activities can test means to

increase commercial harvests of matsutake mushrooms and provide new information about matsutake mushroom management. Traditional management for

matsutake mushrooms in eastern Asia is best suited to low-elevation, singlespecies, even-aged stands receiving summer rain. Uncertainty about appropriate

management for matsutake mushrooms in high-elevation, multispecies, unevenaged stands in the Cascade Range underscores the need for experimental prescriptions designed to clarify direction in matsutake mushroom management. Risk

to net economic yields of forest products from innovation may be alleviated by

concurrently managing timber resources for improved tree vigor and timber quality.

Examples here illustrate potential experimental management at the Diamond Lake

matsutake mushroom management area in the Umpqua National Forest, Douglas

County, Oregon.

Physical

Environment

Location and

Topography

The Diamond Lake matsutake mushroom management area is just west of the

Cascade Range crest in southern Oregon at 43°12’ 7" N. latitude and 122°12’ 20" W.

longitude, about 5.8 kilometers northwest of the north end of Diamond Lake. Elevation

ranges from 1675 to 1750 meters. Slopes within the management area range from

flat to 23 percent. Aspect is from northwest to east. The site is shielded from prevailing southwest winds and resulting windthrow, a prominent phenomenon at other

productive matsutake mushroom sites nearby.

1
Soils The management area is northwest of the Crater Lake caldera in a zone of thick

deposits of volcanic ejecta from the explosion of Mount Mazama 7,000 years ago

(Carlson 1979). Other volcanos in the immediate vicinity are Mount Thielsen (2780

meters) and Mount Bailey (2550 meters). Surface soils in the study site are Cryands,

loamy sands originating from Mazama ash and pumice deposition. Glacial debris is

occasionally mixed in with the volcanic material, but andesite rock with good porosity

underlies topsoil at variable depths (Radtke and Edwards 1976).

Litter and humus layers are generally less than 3 centimeters deep except on steeper,

moister, north-facing sites where stands of Pacific silver fir (Abies amabilis Dougl. ex

Forbes) and mountain hemlock (Tsuga mertensiana (Bong.) Carr) are often dense.

Surface soil layers are low in organic matter and clay compounds (U.S. Department

of Agriculture, soil inventory database samples S82-OR-019-002 and S91-OR-019-

002), in stark contrast to high-elevation volcanic soils in Japan (Kawata and others

1981, Shoji and others 1993) and elsewhere in the southern Cascade Range

(Alexander and others 1993). The prevailing trend of increasing organic litter with

increasing elevation does not apply to the Diamond Lake management area.

In contrast with other Cryand soils in the Cascade Range, soils in the pumice and

ash zone have lower available phosphorus and higher porosity (Meurisse 1987).

Soil bulk density at the Diamond Lake management area is 0.75 gram per cubic

centimeter or less. Water infiltration and permeability are both very rapid. These

features may be altered somewhat when hydrophobic char remains on the soil surface after fires. Water-holding capacity is low because fine pore spaces are few.

Unique physical properties of pumice-derived soils include resistance to compaction

and low rates of heat storage and heat transfer, particularly during drought months

(Meurisse 1987). Temperature can fluctuate widely at the soil surface, often exceeding 70 °C (Carlson 1979, Cochran and others 1967, Palazzi and others 1992)

during the day and below freezing at night, even during summer months. Insulating

properties of the mineral soil damp penetration of diurnal energy fluxes into soil

layers when the soil is dry. Low thermal diffusivity also causes soils to warm slowly

in spring (Cochran and others 1967). Average summer temperature of soils in the

area is 14 °C (Kimble 1993).

Climate High-elevation forests west of the Cascade crest in southern Oregon have a modified

montane mediterranean climate (Redmond 1992) and fall within the high winter precipitation zone in the southern Cascade Range. Most precipitation falls as snow.

Summer rainfall is sparse, usually the result of local thunderstorms. Annual precipitation for the site averages 1525 millimeters.

Vegetation Five conifer species dominate the overstory at the study site: Pacific silver fir, Shasta

red fir (A. magnifica A. Murr. var. shastensis Lemmon), lodgepole pine, western white

pine (P. monticola Dougl. ex D. Don), and mountain hemlock. At lower elevations

within the management site, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco)

and white fir (A. concolor (Gord. & Glend.) Lindl.) occur sparsely. Of the major

species, Pacific silver fir and western white pine appear not to form mycorrhizae

with matsutake mushrooms in the management area.

2
The dominant plant association type (Atzet and others 1996) is mountain hemlock/

grouse whortleberry (Vaccinium scoparium Leib.), which has one of the lowest stand

basal area densities of forest types in the Pacific Northwest west of the Cascade

crest. Stands within the study site have uneven-aged structure with the exception

of even-aged patches of lodgepole pine, particularly in disturbed or moist, frost-prone

areas. Shrub, forb, and grass species diversity is low, as is the percentage of cover

by understory vegetation. Prominent nontree species in the understory and in gaps

include pinemat manzanita (Arctostaphylos nevadensis Gray), golden chinkapin

(Castanopsis chrysophylla (Dougl.) A. DC var. minor (Benth.) A.DC.), squawcarpet

(Ceanothus prostratus Benth.), pipsissewa or prince’s pine (Chimaphila umbellata (L.)

Bart.), and little prince’s pine (C. menziesii (R. Br. ex D. Don) Spreng). A list of fungi

species at the sites has not yet been compiled.

Flat or gently sloping terrain make regeneration difficult because of frequent frosts.

Clearcut gaps greater than 8 hectares are difficult to regenerate either naturally

(Atzet and others 1992, Franklin and Smith 1974) or with planting (Halverson and

Emmingham 1982). Advance regeneration, except for shade-intolerant lodgepole

pine, usually responds well to small gap openings (Cromack and others 1991).

Suppressed small trees in the understory, particularly Pacific silver fir trees, may

be 40 or more years old.

Key Management

Concerns

Few silviculturists have attempted intensive management for timber production

at high-elevation sites in the zone of Mount Mazama pumice and ash deposition.

Establishing economically desirable but poorly adapted species, such as Douglas-fir,

and clearcutting at high elevations retards stand regeneration and growth (Halverson

and Emmingham 1982). Small gap disturbances (Cromack and others 1991) are

more typical of the characteristically uneven-aged structure of high-elevation forests

in the Cascade Range, especially on flat or on moister north-facing slopes. Advance

regeneration also responds well to overstory removal (Helms and Standiford 1985,

Tucker and others 1987).

Susceptibility of most tree species to one or more persistent plant parasites and

fungal and insect pathogens requires vigilant stand tending to promote tree growth.

Necessary investments for sanitation cuts, site preparation, tree planting or seeding,

and precommercial thinning for spacing usually exceed expected discounted revenues. Plantings of preferred species grow poorly, if they survive, and less preferred

species that regenerate naturally grow slowly. Sole focus on timber as the source

of revenue from high-elevation stands overlooks options for joint production such as

combining matsutake mushrooms and timber.

3
Grier and others (1989) point out that investments in forest stands should not be

based solely on net primary aboveground productivity. Sites yielding products with

disproportionately high economic value per unit of biomass may in the long run be

advantageous to manage, and may garner broad public support for intensified management as well. Both forest incomes and forest structure can be maintained. Mixing

crops with different harvest intervals also helps to even out flows of income at the

stand scale. Stand-level even flow of resource benefits is a fundamentally different

notion from even flow of timber income from annual harvesting of a fixed percentage

of a forest landscape. Nearly annual crops of wild mushrooms, of triennial boughs

crops, decadal crops of Christmas trees, and partial timber cuts every 25 to 50 years

may extract commercial biomass at a higher average annual rate than intensive

management of a single timber crop. Investing in an array of valuable crops, such

as high-quality western white pine timber and matsutake mushrooms, with long

histories of consumer demand globally, cushions uncertainty about future markets

and management costs.

Management for matsutake mushrooms in high-elevation stands remains risk laden

because there is no indigenous tradition of mycoforestry based on centuries of

refinement through trial and error. Managers need to have options in the event

that assumptions underpinning novel management for matsutake mushrooms fail

to hold up in practice. Failure-resistent management in the Pacific Northwest mixes

comparatively secure knowledge about timber species, based on a history of management and research, with experimental alternatives based on extrapolations from

other ecosystems and adaptive learning through small-scale experimentation and

monitoring.

The matsutake mushroom management area at Diamond Lake is challenging

because species diversity and biological productivity are both low. Emphasizing

individual management activities that improve quantities or qualities of several

resources at once can make management more efficient and lucrative. Interventions that mimic disturbance regimes natural to the ecosystem are likely to

speed recovery of ecosystems without hiatus in ecosystem productivity. Smallscale disturbances also are less likely to disturb the amenity values of highelevation forests, because the forest structure remains relatively unmodified or

rebounds quickly.

Another set of management experiments, not discussed in depth here, but just as

important to the success of stand management of high-elevation agroforestry systems, would develop a workforce and new institutions to handle new agroforestry

products (Everett 1996). Multiproduct management described here is more labor

intensive than traditional timber-based extraction. Improved links between nontraditional ecosystem products and their markets are needed. Programs for certification of sustainable harvests and establishment of cooperative or communitybased institutions must parallel the development of stocks of novel nontimber forest

products (Mater Engineering, Ltd. 1992). Without a secure forest-based labor force

and organized networks to distribute nontimber forest products to consumers, the

justification for more intensive forest management remains incomplete.

4
Constraints based on societal amenity values prevent maximization of financial

benefits from forest product goods. Amenity values such as aesthetics, recreational

opportunities, and conservation of biological diversity are more difficult to quantify

than values for forest products. These values are not explicitly included here as

outputs; instead, amenity values function as constraints to management. In some

cases, management for a commercial resource ensures that one or more amenity

values are preserved. For example, management concerns for aesthetics and

adequate tree regeneration coincide. Favoring partial cutting with considerable

overstory retention maintains old-growth trees and old-growth-dependent species

and creates a visually diverse landscape. Current work underway near the Diamond

Lake matsutake mushroom management area will describe in detail public responses

to the aesthetics of partial overstory retention.1

All tree species found originally in the stands before management are retained to

some degree in managed stands under the assumption that total biological diversity

is therefore conserved at the stand level. Biological diversity at higher geographical

orders likewise constrains management in terms of wildlife corridors and large-scale

wildlife habitat needs. Specific constraints tied to adjacency and landscape connectivity are not specifically addressed here.

Management

Experiments

A range of stand prescriptions described here implements agroforestry systems

that jointly produce timber, matsutake mushrooms, decorative boughs, Christmas

trees, and pine cones. The prescriptions elaborated here have not yet been implemented on the ground; Weigand (1997) developed them in consultation with Umpqua

National Forest staff for computer modeling of the production and value of multiple

forest products, both timber and nontimber, over 25 years. Table 1 gives an overview of major timber and nontimber products currently or potentially available in the

Diamond Lake matsutake mushroom management area. Each prescription tests the

feasibility of one or more management options as tools for overcoming barriers to

investment in high-elevation stands for cropping nontimber products listed in table 1.

Harvests of one or more nontimber products early in the cutting cycles in an unevenage management regime may generate sufficient income to finance costs for augmenting stand productivity. Monitoring these interventions will help evaluate whether

agroforestry management practices leave stand structures and ecosystem processes

intact and produce expected results.

Management with a multiproduct approach emphasizes product quality for timber

produced in small quantities at long intervals. Although attention to quality may

produce highly desirable products from high-elevation forests, the time until harvest,

upfront costs, technological changes, and changing product markets make for considerable risk and uncertainty. Initial assumptions and practices for agroforestry

prescriptions will likely require periodic revision. In this way, an adaptive strategy

uses new information as it becomes available to revise management during a cycle

of uneven-aged management.

1 Ribe, Robert G. 1994. Critical public perceptions of

alternative forest managements in the Cascade Range

of the Pacific Northwest: demonstration of ecosystem

management options, social perceptions study component,

study plan proposal. Unpublished manuscript. 27 p. On file

with: U.S. Department of Agriculture, Forest Service, Pacific

Northwest Research Station, Forest Sciences Laboratory,

P.O. Box 3890, Portland, OR 97208-3890.

5
Effects of forest management practices on North American matsutake mushrooms

are poorly known. Most information about responses by matsutake mushrooms to

changing forest production include altering stand tree species composition (Iwamura

and others 1966), irrigation (Ishikawa and Takeuchi 1970), overstory thinning (Lee

1981), cutting understory shrub and forb species (Ito and Ogawa 1979), artificially

covering matsutake mushroom colonies at fruiting time (Lee 1989), and removing

organic litter from the forest floor (Hosford and others 1997).

Describing desired conditions achieved from such manipulations is as important

as describing practices. Management for Asian matsutake mushrooms strives for a

forest canopy with light gaps, a forest floor with a thin organic litter layer and sparse

vegetation, and thriftily growing trees. The result is a soil environment exposed to a

greater range of energy and water fluxes and a greater number of fine conifer roots

close to the soil surface and available for mycorrhizal formation with matsutake mushroom mycelia than if natural vegetation developed unhindered.

Table 1—Potential agroforestry products from the Diamond Lake matsutake

mushroom management area, Diamond Lake Ranger District, Umpqua National

Forest, Oregon

Product category Estimated price per

and product unprocessed unit Source

1990 U.S. dollars

Foods and flavorings:

Tricholoma magnivelare 22.00/kg Amaranthusa

Chimaphila umbellata, 4.18/kg Miller 1988

Chimaphila menziesii

Decorative cones:

Pinus contorta .75/kg Thomas and Schumann 1993

Pinus monticola 1.33/kg Thomas and Schumann 1993

Decorative boughs:

Abies amabilis (open-grown) .35/kg Schlosser and Blatner 1996

Abies magnifica .35/kg

Pinus contorta 0-.20/kg

Pinus monticola .25/kg

Tsuga mertensiana 0-.25/kg

Christmas trees:

Abies amabilis (open-grown) 1.82 per tree USDA Forest Service 1996

Abies magnifica 1.82 per tree

Wood products:

Abies amabilis 230.08/mbfb USDA Forest Service 1996

Abies magnifica 205.25/mbfb

Pinus contorta 88.01/mbfb

Pinus monticola 299.45/mbfb

Tsuga mertensiana 234.64/mbfb

a Personal communication. 1997. Michael Amaranthus, research forester, formerly with the Pacific

Northwest Research Station.

b mbf = thousand board feet.

6
Forest managers can create analogous environments in high-elevation forests in the

southern Cascade Range where the stand structures, soils, and climate are different.

For example, north-facing slopes are often favored for production of matsutake mushrooms in the Diamond Lake area as compared to dry southwest slopes in Japan and

Korea (Hosford and others 1997, Lee 1983). South- to west-facing slopes may be too

severe for commercial production in the Diamond Lake region because of summer

drought. Certain practices such as cutting understory vegetation are of little concern

at the Diamond Lake management site owing to the naturally sparse understory.

Other environmental effects, such as fire frequency, are of greater concern in the

Cascade Range but not significant in the wet summer climate of Japan.

The tradition of matsutake mushroom management in eastern Asia serves as a point

of departure from which to synthesize and test hypotheses about promising options

for managing North American matsutake mushrooms. Basic differences in climate,

soils, and tree species, however, point to the need to manage for matsutake mushrooms in commercial timber forests with objectives, goals, and practices adapted to

local site conditions.

Management

Objectives and

Goals

Management for matsutake mushrooms strives to enhance biological productivity and

rates of biological processes as the means to expand commercial production. To this

end, management has four objectives:

• to improve tree resistance to pathogenic species

• to increase growth of individual trees

• to direct composition of regenerating trees to desired species

• to expand suitable habitat for matsutake mushrooms

These objectives emphasize product quality but allow for flexibility to chose the best

means in response to changing economic demands in the future.

Overarching management goals for different stands within the Diamond Lake

matsutake mushroom management area were established in alternative scenarios

for the first 25-year cycle of uneven-aged management. Goals in management are

highly likely to change in that time, however. Adaptive adjustments to surprises or

new information necessitate flexibility that will alter management for North American

matsutake mushrooms in response to economic signals and technological advances.

One hypothetical example of an adaptive change in matsutake mushroom management might involve efforts to regenerate Pacific silver fir were new evidence to show

that it is a matsutake mushroom host species and that it creates suitable forest environments for commercial quantities of matsutake mushrooms. Potential advances in

culturing Asian matsutake mushrooms under intensive domestication, on the other

hand, might reduce demand for North American matsutake mushrooms in Japan,

the major consumer market.

7
Experimental

Treatment

Strategies

Five strategies, described briefly in the following paragraphs, define the direction of

management of high-elevation forests for agroforestry joint production:

• adhere to known societal and ecological constraints

• reduce populations of tree pathogens by controlling the mix of tree species in

different age or diameter classes

• reduce the presence of Pacific silver fir and increase the presence of western

white pine

• thin and prune trees to concentrate nutrients and organic matter on fewer trees

• harvest nontimber products when commercial quantities are available

Adhere to Societal and

Ecological Constraints

Management scenarios proposed here assume that society’s interests in public forests

are best served by maintaining stand structure and biological diversity as well as by

even flows of forest products through time. All products considered for agroforestry

systems rely on forest structure and function being maintained indefinitely. No species

originally in a stand is entirely eliminated from the stand. Shifts in species dominance

are, however, planned as part of efforts to reduce tree pathogens and improve the

quality and quantity of economic production. The focus of regeneration is management of gaps of less than a hectare. Management is designed to maintain robust

old-growth trees where present and to foster diverse combinations of trees species

and tree ages. To maintain uneven-aged forest structure, timber harvest operations

are more complex and therefore more costly.

Reduce Tree Pathogens Inventory records from the Diamond Lake Ranger District showed multiple widespread tree pathogens in the matsutake mushroom management area. Management for reducing pathogen populations is directed to improve tree growth. Initial

timber harvests are sanitation harvests to remove diseased or mistletoe-infested

trees, to reduce drought stress on trees, and to improve growth rates for diseasefree advance regeneration and subsequent natural regeneration. Initial harvests

are the most extensive in the uneven-aged management program. Improved tree

growth, in turn, is hypothesized to favor matsutake mushroom production by supplying more fine root sites for mycorrhizae-mediated carbohydrate supplies to

matsutake mushroom mycelia. Integrating management practices for pathogen

control also avoids worsening effects of one pathogen in the process of alleviating

effects of another.

In the Diamond Lake region, dwarf mistletoe infestations affect growth of Pacific

silver fir, mountain hemlock (both infested by Arceuthobium tsugense (Rosendahl)

G. N. Jones subsp. mertensianae Hawksworth and Nickrent), and lodgepole pine

(infested with A. americanum Nutt. ex Engl. in Gray). Diamond Lake is just outside

the range of high species diversity of Arceuthobium spp. at the extreme south end of

the Cascade Range in northeast California. Consequently, both western white pine

and Shasta red fir are largely immune to mistletoe parasitism in the Diamond Lake

area2 (Hawksworth and Wiens 1996).

2 Personal conversation, Norman Michaels, silviculturist,

U.S. Department of Agriculture, Umpqua National Forest,

Diamond Lake Ranger District, Diamond Lake, Oregon.

8
Alternating species composition in the overstory and understory can break cycles of

infestation or infection from one cohort to the next. For example, mountain hemlock

or lodgepole pine may be retained in overstories for biological and structural diversity,

or for maintaining existing matsutake mushroom colonies. At the same time, promoting gaps and open understories composed of Shasta red fir and western white

pine interrupts cycles of mistletoe infestation in the understory from A. tsugense

or A. americanum. Shelterwood trees or seed trees that regenerate the three tree

species infested by mistletoes are planned for harvest within 5 to 10 years after

opening gaps in the forest. Vector trees for mistletoe infestations, particularly from

the control plots, are kept at least 20 meters away (Hawksworth and Wiens 1996)

from understory or gap regeneration of the same species in nearby experimental

plots.

White pine blister rust (Cronartium ribicola Fisch.) and western gall rust (Endocronartium harknessii (J. P. Moore) Y. Hiratsuka) infect western white pine and lodgepole pine, respectively, and cause widespread mortality (Hoff 1992, Snellgrove and

Cahill 1980). The principal measure to control fungal infection is to prune limbs of

trees closest to the ground. Hungerford and others (1982), Hagle and others (1989),

and Russell (1995) offer prescriptions for stocking and pruning to improve tree growth

and vigor over long rotations. Lodgepole pine also benefits from stocking control and

pruning (Cole and Koch 1995, Lishman 1995).

Reduce Pacific Silver Fir

and Increase Western

White Pine

All tree species at the Diamond Lake management area are valued timber species,

but western white pine is the most valuable tree for timber production (table 1). Its

clustered foliage and comparatively low leaf area of individual trees also contribute to

more open stand canopies in contrast to Pacific silver fir. Pacific silver fir is the most

shade-tolerant conifer in the area and creates dense stands of slow-growing trees

and thick organic litter layers. Litter builds up on the forest floor in dense stands without sharp diurnal and seasonal high fluxes of solar energy on the forest floor. High

leaf area indices and deeper litter layers in stands dominated by Pacific silver fir

intercept inputs of energy and water into the soil. Interception at crucial times in the

life history of matsutake mushrooms may reduce or delay water and energy transfers

necessary to induce matsutake mushroom growth and reproduction.

Thin and Prune Opening the overstory, by stand thinning and by selecting species with naturally

more open canopies, permits stronger pulses of solar energy and water to reach

upper soil layers at the time of matsutake mushroom fruiting. Thinning trees and

pruning branches both reduce leaf area index, although the intensity of control differs

with each practice. Thinning reduces drought stress and concentrates biomass on

trees having the best prospects for financial returns or on trees promoting the best

environment for matsutake mushrooms. Wood quality of pine species, in particular,

improves and tree taper is reduced (O’Hara and others 1995b). Pruning to the height

of the first merchantable log (5.3 meters) increases value to the tree bole where the

timber dimension, and therefore value, is highest. To date, no information is available

about benefits of pruning true fir and hemlock species for wood quality in the Pacific

Northwest. An additional topic for original management experiments would be to overlay pruning and nonpruning treatments to randomly selected management circles

in the matsutake mushroom management area. General pruning guidelines are

presented in the following tabulation. Pruning of lodgepole pine trees differs from

the other tree species because of its shade intolerance. Retaining more live crown

is necessary for longer retention in mixed-species stands.

9
Pruning guidelines

Species Height class Pruning height

Meters

For all trees species,

except pines: >5.0 2.5

>13.0 5.3

For western white pine: >2.5 1.2

>5.0 2.5

>13.0 5.3

For lodgepole pines in a stand where they comprise more than 60 percent of stand

basal area:

Prune as for nonpine species.

For lodgepole pines in a stand where they comprise less than 60 percent of stand

basal area:

Prune only if trees have a crown ratio greater than 75 percent.

>4.8 1.2

>10.0 2.5

>20.0 5.3

Sources: Hungerford and others 1982; O’Hara 1995a, 1995b; Russell 1995.

Harvest Nontimber

Forest Products

Opportunistically

Harvests of nontimber forest products, including boughs, Christmas trees, and

pine cones in addition to matsutake mushrooms, provide opportunities to generate

income that offset costs of conventional “precommercial” thinnings of young trees.

Bough harvests and Christmas tree harvests reduce stand density and leaf area

index. Timing of these harvests is difficult to predict in advance because existing

yield models for these products are not very sophisticated (Weigand 1997). Favorable market conditions, harvest timing, and supply availability on site are essential

factors to determine feasibility of these harvests. The minimum for a commercial

bough harvest is 2.2 metric tons of commercial grade boughs per hectare. Christmas

tree sales are possible when the number of open-grown true firs per hectare with

diameters at breast height (d.b.h.) between 1 and 10 centimeters exceeds the retention target for that diameter class by 125 or more trees per hectare. About one in

three years in the Diamond Lake area, western white pine trees have a large cone

crop (Franklin and others 1974). Trees must be at least 3.0 meters tall and sufficiently dense in numbers to make cone collecting profitable.

10
Table 2 presents matsutake mushroom management practices and their presumed

effects for high-elevation forests. These practices are incorporated into experiments

tied to practical, site-specific management at Diamond Lake.

Table 2—Outline of management practices, expected outcomes, and underlying assumptions at the

Diamond Lake matsutake mushroom management area

Management practices Expected outcomes Underlying assumptions

Thinning the overstory Thinning trees improves matsutake mushroom Open stands have increased individual tree growth and nutrient cycling.

production. Increased energy and water reach the soil.

Fluctuations in available water and energy are more extreme.

Pruning low branches Tree pruning improves matsutake mushroom production. Pruning reduces canopy interception of water and energy.

Pruning improves survival of western white pine. Pruning of branches prevents invasion by white pine blister rust.

Pruning improves the quality and value of timber. Butt logs of pruned trees produce more high-value, knot-free wood.

Spatially integrating Matsutake mushroom management and timber Matsutake mushrooms and their management do not affect growth

mushroom and production from rust-resistant western white pines and management for western white pine timber crops.

timber crops are compatible activities.

Directing tree species Mountain hemlock is the best tree species to host Mountain hemlock regenerates best in soils with an organic litter layer.

composition matsutake mushrooms on cold, moist sites. Shifting stand dominance from Pacific silver fir to mountain hemlock

increases production of matsutake mushrooms over time.

Lodgepole pine is the best tree species to host Lodgepole pine regenerates best on disturbed, exposed surfaces.

matsutake mushrooms on burned sites and riparian Lodgepole pine stands develop commercial matsutake mushroom

sites. colonies at high elevations.

Shasta red fir is the best tree species to host matsutake Shasta red fir dominates regeneration on flat sites with partial

mushrooms on flat, well-drained sites. overstory retention.

Shasta red firs host the most productive matsutake mushroom

colonies.

Altering the organic Increasing the amount of organic matter on the Soil organic matter makes soil more fertile for tree growth.

litter layer forest floor improves tree growth but depresses Thicker organic layers favor increased diversity of mycorrhizal fungi.

production of matsutake mushrooms. Matsutake mushrooms do not compete strongly with most other fungi.

Relying on natural Natural regeneration of host tree species is the most Natural regeneration produces the desired species mix for

regeneration cost-effective way to regenerate timber trees. multiproduct agroforestry systems.

Retaining old-growth Partial cutting retains old-growth trees and sustains Old-growth trees are natural foci of matsutake mushroom colonies at

trees productivity of matsutake mushroom colonies. high elevations.

Piling and burning Fires reduce the survival of matsutake mushroom Mycorrhizae and mycelia lie near the soil surface and are damaged

slash colonies. by fire.

Concentrating slash burns into small areas minimizes negative effects

of fire on matsutake mushroom colonies.

11
Management Design An experimental management approach increases the certainty that forest managers

draw valid inferences about effects of management practices. Three stands are considered here to demonstrate a range of options available to land managers for improving joint resource production and revenue. Data from Umpqua National Forest stands

355, 357, and 401 are given in table 3. Within each stand, five replications were

selected, each consisting of four plots. Each replication totals 9 hectares. Plots within

replications were randomly assigned to one of three prescriptions or to the control

treatment with no management. Each experimental plot covers 1 hectare and has a

25-meter-wide buffer treated the same way, for 2.25-hectare total forest area. The

two 25-meter-wide buffers between experiment plots reduce edge effects in the experiment plots. Buffers mitigate seed and spore dispersal and spread of tree pathogens from adjacent plots, particularly from control plots.

The experimental design will produce statistically valid information under constraints

of natural variation in site conditions, including within-stand variation, at Diamond

Lake. A key feature is the irregular distribution of matsutake mushroom colonies

in forest stands. Placement of replications is designed to assure that numbers of

existing colonies, or the absence of colonies in stand 357, are similar among the

treatment plots and the control plot of any one replication. Stands are uniform so

that random placement of replications reproduce similar environmental conditions.

Table 3—Features of stands used in management experiments at the Diamond

Lake matsutake mushroom management area

Stand feature Stand 355 Stand 357 Stand 401

Elevation (meters) 1735 1705 1675

Aspect NW to NE NW to NE W to NE

Slope (percent) 5 10-23 15

Position Ridge Mid to bottom

of slope Upper slope

Western white pine

100-yr site index (meters) 29 30 23

Basal area (m2

/ha) 24.6 53.4 60.1

Major overstory speciesa MH SF, MH SF

Minor overstory speciesa RF, WP LP, WP LP, WP

Understory speciesa All 5 species SF (MH) SF, LP

Fungal infectiona WP, LP WP, LP WP, LP, RF

Mistletoe infestationa SF, MH SF, MH —

Drought stressa — SF, MH RF

Timber quality Poor Poor Poor

a LP = lodgepole pine, MH = mountain hemlock, RF = Shasta red fir, SF = Pacific silver fir, and

WP = western white pine.

12
Stands 355 and 401 retain old-growth trees of host species for matsutake mushrooms. Each experimental plot contains 16 management circles with 25-meter

diameters. Figure 1 shows the schematic form of a plot surrounded by its buffer,

and figure 2 depicts, from overhead, a matsutake mushroom management circle

surrounded by interstitial cohorts of western white pine. Layout of management

circles was designed to not disrupt the current distribution of matsutake mushroom

colonies.

Where colonies already exist within a circular subplot, one or more anchor trees of

the host tree species are designated by location and pattern of previous matsutake

mushroom fruiting. Anchor trees are foci of colonies and will be retained indefinitely,

potentially up to 800 years, as long as they do not infect gap and understory regeneration with pathogens that undermine tree growth. Individual management circles

may not always have preexisting matsutake mushroom colonies. Experimentation

within each treatment plot involves a treatment program to maintain existing colonies

and establish new colonies.

Slash disposal from timber harvests needs to minimize damage to existing matsutake

mushroom colonies in plots and minimize any obstacles to reestablishing trees and

fungal colonies. Where possible, management practices convert harvested biomass

into merchantable timber, pulpwood, and decorative conifer boughs. Burning piled

unmerchantable slash away from the treatment plots may be unavoidable, however.

Buffer area

Plot

- - 25 m - -

Management

circle

Figure 1—Plot configuration of one treatment.

13
No vegetation management takes place in control plots. The only direct human

manipulation is annual harvests of matsutake mushrooms. Comparison of mushroom yields between unmanaged plots and treatments measures the efficacy of

treatments to increase production. Also, in a financial analysis, the controls allow for

a comparison to see whether joint production from more intensively managed plots

has greater net present value than single-product harvests of matsutake mushrooms

from control plots. If intensified management is not found to be financially feasible

or socially desirable, the control plots can serve as original forest remnants that can

hasten development of forest stand conditions similar to premanagement conditions.

Figure 2—Generic scheme of a matustake mushroom management circle.

14
In the interstices between management circles in stands 355 and 401, blister rustresistant western white pine trees are planted. These trees are timber crop trees on

100-year or longer rotations with potential retention of robust old-growth trees. This

effort supports regional objectives of the USDA Forest Service to restore western

white pine into stands where it has disappeared after previous blister rust infections.

Inclusion of western white pine is also a hedge if all efforts to manage matsutake

mushroom colonies should fail. An important management consideration is whether

western white pine trees, an apparent nonhost tree species for matsutake mushrooms, can be grown concurrently in stands also managed for matsutake mushrooms.

One part of the management system is monitoring the response of western white

pine to stand treatments intended to augment matsutake mushroom production.

The role of western white pine is different in stand 357. Western white pines are

planted as a row crop in combination with naturally regenerating Pacific silver fir,

Shasta red fir, or lodgepole pine. Stand 357 tests whether there are sites where

emphasizing timber production with nonhost species (western white pine and Pacific

silver fir) outweighs the combined value from timber and mushrooms in joint production. This question is especially important if managers are contemplating introducing

matsutake mushroom colonies and their host tree species into stands where host

trees and matsutake mushrooms were previously absent.

Vegetation Patterns The Diamond Lake experiments aim to retain an uneven-aged forest structure,

albeit with different species composition and ratios among different age classes

than might be found in control plots. Except for stand 357 just noted, the pattern

of canopy development consists of even-aged cohorts of western white pine intermingling with uneven-aged management circles comprised mostly of the true firs

and mountain hemlock. Lodgepole pines remain in small numbers except in one

treatment each in stands 357 and 401 and in any piled slash burn sites. Plots with

lodgepole pine are originally even-aged but eventually revert to an uneven-aged

system as advance regeneration of different species establishes itself in the understory in the time between the second to last cut and the final cut of a lodgepole pine

cohort. A shifting mosaic of uneven-aged tree cohorts results in trees growing at

lower densities than might be expected in unmanaged sites. An important advantage

of slow growth and low productivity of trees in high-elevations forests with ash and

pumice soils is the protracted period of stand conditions beneficial to high matsutake

mushroom production. Annual understory vegetation control of the kind typical for the

understory in Japan or Korea is not required at Diamond Lake. Small-scale timber

tree harvests adjust canopy structure and stand tree density every 25 to 50 years

along with approximately decadal tree pruning and Christmas tree sales to extend

matsutake mushroom production indefinitely in uneven-aged forests.

Each of the stands presented here has a different set of treatments tailored to conditions in that stand. Treatments support stand management objectives. Experimental

variations for stands are found in following sections. Details of stand management

common to all three treatment prescriptions in a stand are then described in the

appendices.

15
Experimental

Management:

Stand 355

The objective for experimental managment is to convert the stand to an uneven-aged

structure.

Immediate goals for stand development are:

• reduce mistletoe infestation by removing all mountain hemlock trees taller than

breast height

• reduce white pine blister rust infections by removing all western white pine trees

taller than breast height

• create an uneven-aged, multispecies stand that improves tree growth rates and

increases in high-quality timber from western white pine in the long term

• make Shasta red fir and mountain hemlock the major host species for matsutake

mushroom colonies to increase commercial production of matsutake mushrooms

in the near term

Assumptions being tested are:

• relying on natural regeneration is the most cost-effective means for regenerating

the desired species composition to provide host trees for matsutake mushroom

colonies

• partial overstory removal creates and spreads matsutake mushroom colonies as

well as increases commercial production

• pruning improves forest floor conditions for matsutake mushroom crops, increases

timber value, and improves the resistance of matsutake species to fungus infection

• measures to improve production of matsutake mushrooms do not adversely affect

western white pine tree growth

Table 4 outlines the objectives, experimental design, hypotheses, prescriptions for

agroforestry systems, and one option for incorporating further experimentation. Figure

3 renders a schematic cross-section of trees in treatment plots at year 25 for each of

the three prescriptions for stand 355.

Outline of Prescription

Variables

Prescription 1: Stand regeneration with a Shasta red fir overstory—In year 0,

harvest all trees taller than breast height except for:

• up to 30 Shasta red fir trees per hectare > 50 centimeters d.b.h., spaced with one

to two trees in each management circle as anchor trees.

Rationale: Large trees, except for Shasta red fir, in the stand are infested with mistletoe, infected with pathogenic fungi, or have defective form. Most pathogens do not

damage Shasta red fir at Diamond Lake. Cutting the infected trees would remove

sources of tree pathogens and permit restructuring the stand to consist of clumped

overstory patches of Shasta red fir and western white pine. Residual old Shasta

red firs harbor matsutake mushroom colonies and furnish a seed source desired

for natural regeneration to reduce, in part, expenses for tree planting. Vigorous,

smaller Shasta red firs can respond to overstory openings for more rapid growth.

16
Table 4—Objectives, experimental design, hypotheses, and prescriptions for agroforestry systems, stand 355, Diamond Lake Ranger

DistrictObjective Strategies Study design Hypotheses Prescriptions ConstraintsDraw greater revenue from Learn which management Create 5 replications Composition of tree 1. Retain 30 old-growth Maintain ecosystem processes.high-elevation forests practices are most effective for of 3 treatments plus a species in the overstory Shasta red firs per hectare in Retain original species diversity.

increasing matsutake mushroom control plot. Treatments influences the production 16 management circles per Leave intact amenity values ofyields in stands dominated change the composition of of matsutake mushrooms hectare aesthetics and recreation.by Shasta red fir. species in the overstory and the vigor of colonies. Confine disturbances to the

and develop understory 2. Retain 15 old-growth range and frequency of natural

Learn which practices and regeneration and further Species in the overstory Shasta red firs per hectare variation.products jointly produce the management goals do not affect matsutake and 15 old-growth mountainhighest net present value. to promote tree vigor. mushroom production or hemlocks per hectare in 16

the vigor of colonies. management circles per

Learn what spatial scale of hectare.gap disturbance works best to Density control ofculture matsutake mushroom overstory trees and tree 3. Retain 30 old-growthcolonies. regeneration increases mountain hemlocks per hectare

production of matsutake in 16 management circles per

Learn how intensive mushrooms. per hectare.management of mushroomcolonies affects adjacent Density control does 4. Control plot withoutwestern white pines grown not affect matsutake treatment.for high-quality timber. mushrooms.

Additional option Randomly design within each

treatment replication a pruning/no pruning treatment onregenerating trees in 8 of the16 circles per hectare.

17
Figure 3—Projected stand structure for stand 355 in 25 years.

18
Target species for regeneration are Shasta red fir (600 trees per hectare), mountain

hemlock (250 trees per hectare), and western white pine (250 trees per hectare).

In year 25, thin to meet targets for species retention:

mountain hemlock—

• retain the 250 most vigorous trees per hectare between 0 and 18 centimeters d.b.h.

Shasta red fir—

• retain the 250 most vigorous trees per hectare between 0 and 18 centimeters d.b.h.

Rationale: Stand thinning across all d.b.h. classes is necessary to maximize growth

on individual trees and to select for trees of host species of matsutake mushrooms

that have the greatest likelihood of advancing commercial production of matsutake

mushrooms.

Prescription 2: Stand regeneration with a Shasta red fir/mountain hemlock

overstory—In year 0, harvest all trees taller than breast height except:

• 15 Shasta red fir trees per hectare > 50 centimeters d.b.h.; and

• 15 mountain hemlock trees per hectare, with trees, regardless of species, spaced

with one to two trees in each 25-meter-wide management circle as anchor trees.

Rationale: Overstory retention of old-growth mountain hemlocks and Shasta red

firs may conserve long-lived matsutake mushroom colonies and allow for inoculation

of young Shasta red fir regeneration. An understory lacking mountain hemlock regeneration and with a small number of Pacific silver fir trees interrupts the spread of

dwarf mistletoe.

Target species for regeneration are Shasta red fir (850 trees per hectare) and

western white pine (250 trees per hectare).

In year 25, thin to meet targets for species retention:

mountain hemlock—

• retain 15-30 trees per hectare > 50 centimeters d.b.h., one to three trees per

25-meter-wide management circle

Shasta red fir—

• retain 15-30 trees per hectare > 50 centimeters d.b.h., one to three trees per

25-meter-wide management circle

• retain the 500 most vigorous trees per hectare between 0 and 18 centimeters d.b.h.

Rationale: Stand thinning across all size-age classes maximizes growth on individual

trees and selects for host trees that have the greatest likelihood of advancing commercial production of matsutake mushrooms.

Prescription 3: Stand regeneration with a mountain hemlock overstory—In year

0, harvest all trees taller than breast height except:

• 30 mountain hemlock trees per hectare > 50 centimeters d.b.h. spaced with 2 to

4 trees in each 25-meter-wide management circle as anchor trees.

19
Rationale: Overstory retention of mountain hemlock and development of vigorous

gap and understory Shasta red fir trees may conserve long-lived matsutake mushroom colonies and allow for infection of young Shasta red fir regeneration. An

understory without mountain hemlock regeneration interrupts the cycle of dwarf

mistletoe infestation on young trees.

Target species for regeneration are Shasta red fir (850 trees per hectare) and

western white pine (250 trees per hectare).

In year 25, thin to meet targets for species retention:

mountain hemlock—

• retain 30 to 60 trees per hectare > 50 centimeters d.b.h., two to four trees per

25-meter wide management circle.

Shasta red fir—

• retain the 500 most vigorous trees per hectare between 0 and 18 centimeters d.b.h.

Rationale: Stand thinning across all diameter size classes is necessary to maximize

growth on individual trees and to select for host trees that have the greatest likelihood

of advancing commercial production.

Prescription 3: Stand regeneration with a mountain hemlock overstory—In year

0, harvest all trees taller than breast height except:

• 30 mountain hemlock trees per hectare > 50 centimeters d.b.h. spaced with 2 to

4 trees in each 25-meter-wide management circle as anchor trees.

Rationale: Overstory retention of mountain hemlock and development of vigorous

gap and understory Shasta red fir trees may conserve long-lived matsutake mushroom colonies and allow for infection of young Shasta red fir regeneration. An

understory without mountain hemlock regeneration interrupts the cycle of dwarf

mistletoe infestation on young trees.

Target species for regeneration are Shasta red fir (850 trees per hectare) and

western white pine (250 trees per hectare).

In year 25, thin to meet targets for species retention:

mountain hemlock—

• retain 30 to 60 trees per hectare > 50 centimeters d.b.h., two to four trees per

25-meter-wide management circle

Shasta red fir—

• retain the 500 most vigorous trees per hectare between 0 and 18 centimeters d.b.h.

Rationale: Stand thinning across all diameter size classes is necessary to maximize

growth on individual trees and to select for host trees that have the greatest likelihood

of advancing commercial production.

Prescription 4: Control plot—In years 0 through 25, no vegetation management

is planned. Harvests of matsutake mushrooms may occur every year. Management

practices common to prescriptions 1 through 3 for stand 355 are given in appendix 1.

20
Experimental

Management:

Stand 357

The objective of stand management is to shift tree species composition and convert

the current even-aged stand structure to an eventual uneven-aged structure.

Immediate goals for stand development are:

• reduce the proportion of advance regeneration of Pacific silver fir in the understory

• produce high-quality timber with western white pine

• maximize net present stand value with a single product (timber) or a combination

of products (timber and either mushrooms or Christmas trees)

Assumptions being tested are:

• emphasis on timber production using western white pine and a host tree species

for matsutake mushroom colonies effectively alters stand composition for increased

tree vigor and financial returns

• measures to improve production of matsutake mushrooms do not adversely affect

western white pine tree growth

• tree species selection promotes matsutake mushroom production at sites without

a history of commercial production of matsutake mushrooms

Table 5 summarizes the objective, experimental design, hypotheses, prescriptions,

and one additional option for add-on research for adaptive learning. Figure 4 portrays

the expected stand structure and composition cross sectionally for each of the three

stand management scenarios for stand 357 in 25 years.

Outline Of Prescription

Variables

Prescription 1: High-quality timber production based on western white pine,

with delayed conversion of stand dominance to mountain hemlock and delayed

introduction of matsutake mushroom—This prescription changes stand structure

and composition in two steps: first by thinning the Pacific silver fir population and

introducing western white pine; then by removing a Christmas tree crop consisting

mostly of Pacific silver fir and allowing natural regeneration of mountain hemlock

and any Shasta red fir to dominate natural regeneration. Changes redirect stand

growth to yield some economic production as soon as possible after stand management begins.

In year 0, harvest all trees with heights greater than 1.37 meters and commercialquality boughs from trees not intended for retention.

Rationale: The forest overstory consists of trees with little value at present and no

prospect of improvement. Overstory trees are all foci of fungi pathogens or dwarf

mistletoe. This radical procedure removes most of the infected or infested trees and

changes the light and water status for the residual stand.

Retain 315 Pacific silver fir trees per hectare less than 1.37 meters in height with

good spacing, the longest crowns and best form.

21
Table 5—Objectives, experimental design, hypotheses, and prescriptions for agroforestry systems, stand 357, Diamond Lake Ranger

DistrictObjective Strategies Study design Hypotheses Prescriptions ConstraintsDraw greater revenue from Learn whether changing tree Create 5 replications Management for timber 1. Retain 315 Pacific silver firs Maintain ecosystem processes.high-elevation forests species composition introduces of 3 treatments and a and nontimber conifer per hectare that are less than Obtain early income from thedominated now by matustake mushroom colonies control plot. Treatments products provides the best breast height for harvest as stand to cover costs for standPacific silver fir. into stands without previous change the timing, the early stand income. Christmas trees. Regenerate management costs.

matustake mushroom choice of species for with mountain hemlock seed Improve biological diversity.production. recomposition, and the Management for timber trees. Exclude fire as a tool to alter

nontimber products and matsutake mushroom stand composition.

Learn which host tree species cropped. crops provides the best 2. Retain 25 Pacific silveris best suited to regenerate on early stand income. firs per hectare. Regeneratesites with mid to bottom with mountain hemlock seedslopes. Lodgepole pine is the trees

matsutake mushroom

Learn whether management of host species best suited 3. Remove all but 25 Pacificalternating generations of two to reforest moist sites. silver firs and mountainhost species promotes hemlocks per hectare.permanaent matsutake Mountain hemlock is the Regenerate with lodgepolemushroom colonies under species best suited to pine seed trees.changing stand composition. reforest moist sites.

4. Control plot without

Learn how intensive mushroom treatment.management affects westernwhite pines for timber.

Additional option Partition each treatment

plot into 16 subplots andchange stand density ofregenerating trees to testeffects on timber valuesand mushroom crops.

22
Figure 4—Projected stand structure for stand 357 in 25 years.

23
Rationale: Dense Pacific silver fir understory regeneration causes drought stress

for these trees. By removing the overstory and reducing the density of regeneration,

remaining trees develop open-grown foliage. Open-grown foliage on small Pacific

silver fir trees makes them potentially merchantable as decorative boughs and

Christmas trees3 for early income from the stand.

Retain all mountain hemlocks less than 1.37 meters tall.

Rationale: Favoring retention of young mountain hemlocks promotes stand dominance by mountain hemlock. Western white pine and mountain hemlock eventually

predominate. Target species for regeneration are mountain hemlock (1,200 trees

per hectare) and western white pine (500 trees per hectare).

In year 12, harvest Pacific silver fir trees for Christmas trees and boughs.

Rationale: Twelve years is hypothesized to be the time for residual Pacific silver fir

trees to bear open-grown foliage and have the merchantable size for Christmas trees

(Tucker and others 1987). Removing all but a few Pacific silver fir trees releases

growing space for mountain hemlocks, western white pines, and any Shasta red fir.

Stand conversion to a mountain hemlock stand with western white pine overstory

may require additional mountain hemlock trees to fill gaps created by harvested

Pacific silver fir.

In year 25, thin western white pine to 300 trees per hectare.

Rationale: Thinning reduces stand density to allow more growth on remaining crop

trees.

Harvest commercial-quality boughs from western white pine as well as any Pacific

silver firs not slated for retention.

Rationale: This practice generates some income, improves health of western white

pine, and reduces slash. Slash is piled and burned away from the site.

Thin mountain hemlock regeneration to 625 trees per hectare, and emphasize

retention of inoculated trees with good form and ample spacing.

Rationale: Mountain hemlock creates an even-aged cohort in the stand canopy. The

species also serves as host trees used to spread matsutake mushroom colonies in

the stand.

After year 25, this stand converts to producing matsutake mushrooms later than

the following two stand prescriptions. Commercial production of timber from western

white pine and, to a lesser degree, mountain hemlock, is emphasized. In the longterm, residual trees of the current even-aged cohort of mountain hemlocks will become anchor trees in management circles. Following development of overstories with

mountain hemlock and western white pine, large gaps from thinnings around mountain hemlock anchor trees would promote disturbance without the fire designed to

promote lodgepole pine. Lodgepole pine is hypothesized to be the preferred species

to replace mountain hemlock in gaps and thereby break the pattern of mistletoe infestation from overstory hemlocks to understory hemlocks. Gaps are therefore comparatively large. Slash thinnings to suppress mountain hemlocks growing under or beside

canopy hemlocks may be necessary.

3 Personal communication. 1996. Mark Savage, special

forest products sales coordinator, State of Washington

Department of Natural Resources, Olympia, WA.

24
Prescription 2: High-quality timber production based on western white pine,

with prompt conversion of stand dominance to mountain hemlock and introduction of matsutake mushroom production—In year 0, harvest all trees with

heights greater than 1.37 meters, except for mountain hemlock trees with d.b.h.

> 10 centimeters that will be used as seed trees.

Rationale: The forest overstory consists of trees with little timber value at present

and no prospect for improvement. Short-term retention of mountain hemlocks as

seed trees provides, however, a seed source of mountain hemlock to reinforce a

shift in understory composition to favor mountain hemlock.

Slash all Pacific silver fir regeneration less than 1.37 meters tall.

Rationale: The high density of Pacific silver fir understory regeneration causes

drought stress for trees. Any value for Pacific silver fir regeneration for boughs or

Christmas trees is assumed to be inferior to value created from management to

foster matsutake mushroom production and better tree growth.

Target species for regeneration are western white pine (625 trees per hectare) and

mountain hemlock (1,200 trees per hectare).

In year 5, harvest overstory mountain hemlock that have served as seed trees.

Rationale: If seed-tree mountain hemlocks remain in the stand too long, they act

as vectors for infesting the regenerating mountain hemlocks in the understory with

dwarf mistletoe.

In year 25, harvest commercial-grade pine boughs from western white pine and

possibly from mountain hemlock not marked for retention.

Rationale: This action reduces the amount of slash burned on a subplot in the buffer

area, generates incomes from nontimber forest products, reduces stand leaf area

index, and improves habitat conditions for matsutake mushrooms.

Thin mountain hemlock to 625 trees per hectare for retaining timber crop trees and

future anchor trees in management circles.

Rationale: Crop trees or potential host trees for matsutake mushrooms are grown

at wide spacing for best growth.

Prescription 3: High-quality timber production based on western white pine,

with prompt conversion of stand dominance to lodgepole pine to introduce

matsutake mushroom colonies—In year 0, harvest all trees greater than 1.37

meters tall, except for lodgepole pine with d.b.h. > 10 centimeter that will be used

as seed trees.

Rationale: A radical change in stand composition is desirable. Opening the canopy

and disturbing the organic litter layer during removal of Pacific silver fir can promote

lodgepole pine regeneration better than regeneration of other species.

Slash all but 25 trees per hectare each of Pacific silver fir and mountain hemlock

regeneration less than 1.37 meters tall.

25
Rationale: The high density of Pacific silver fir understory regeneration causes

drought stress for trees. Any value for Pacific silver fir regeneration for boughs or

Christmas trees is considered inferior to immediate implementation of vegetation

management to create or improve matsutake mushroom productivity and better tree

growth. Suppression of Pacific silver fir and mountain hemlock regeneration favors

the predominance of lodgepole pine in stand regeneration.

Species targeted for regeneration are lodgepole pine (1,200 trees per hectare) and

western white pine (625 trees per hectare).

In year 5, harvest overstory lodgepole pines that have served as seed trees.

Rationale: If seed-tree lodgepole pines are retained in the stand too long, they act

as vectors for infesting the regenerating lodgepole pine in the understory with dwarf

mistletoe or western gall rust.

In year 25, salvage pine boughs from western white pine and lodgepole pine trees

not marked for retention.

Rationale: Income from pine boughs can offset costs of precommercial thinnings

and improve timber grade quality and tree resistance to western gall rust.

Thin lodgepole pine trees to retain 600 trees per hectare.

Rationale: These trees eventually will become crop trees, and residual trees can

serve as focal trees for matsutake mushroom production.

Slash understory growth of all species, except mountain hemlock.

Rationale: Promoting mountain hemlock in gaps near clumps of lodgepole pine

sets in place an eventual shift in stand composition from lodgepole pine to mountain

hemlock. In this relay system of alternating stand composition, uneven-aged management with two single-species cohorts may be able to continue indefinitely while conserving matsutake mushroom colonies.

Prescription 4: Control plot—No vegetation management is planned. Harvests of

matsutake mushrooms may occur every year. Management practices common to

prescriptions 1 through 3 are given in appendix 2.

Experimental

Management:

Stand 401

The objective for experimental management is to convert the stand to an unevenaged structure. Immediate goals for stand development are:

• reduce western gall rust and western white pine blister rust infections in regenerating pine species

• create a mosaic in the landscape of predominantly single-species cohorts in each

matsutake mushroom management circle

• manage Shasta red fir for uneven-aged diameter class distribution in management

circles with old-growth retention

• manage pines species under essentially even-aged management by relying on

natural regeneration

26
Assumptions being tested are:

• promoting young, naturally regenerating or planted Shasta red fir around other

old-growth Shasta red fir is an effective method for expanding matsutake mushroom colonies

• relying only on natural regeneration with Shasta red fir is a cost-effective way to

promote tree growth and augment matsutake mushroom production

• measures to improve matsutake mushroom production do not affect growth of

western white pine

• retaining organic matter at mushroom harvest sites affects tree growth positively

and depresses western white pine growth

• directing the species composition improves matsutake mushroom production

These prescriptions have the option of leaving chipped slash on one-half of 25- by

25-meter subplots, randomly selected, in each treatment plot. Such practices may

keep more organic matter and potential mineral nutrients on site and improve growth

of trees and crops of matsutake mushrooms as compared to the practice of burning

slash. Regeneration focuses on Shasta red fir management to produce matsutake

mushrooms.

Table 6 summarizes the objectives, experimental design, hypotheses, prescriptions

for agroforestry systems, and adaptive options for additional research. Figure 5

projects a schematic version of expected stand structure in 25 years.

Outline of Prescription

Variables

Prescription 1: Matsutake mushroom management in uneven-aged stands with

Shasta red fir canopy, young Shasta red fir filling gaps, and cohorts of western

white pine—In year 0, retain 60 Shasta fir trees per hectare with d.b.h. between

18 and 50 centimeters as seed trees.

Rationale: These trees serve a double function: retaining a cohort of mid-sized

Shasta red fir in uneven-aged management within management circles and providing seed trees for natural regeneration.

Retain 60 Shasta red fir trees per hectare with d.b.h. > 50 centimeters with two to

four trees per 25-meter-wide management circles as anchor trees.

Rationale: Old-growth Shasta red fir may be the foci of matsutake mushroom

colonies. These trees maintain habitat for high-elevation old-growth wildlife species.

Although old Shasta red fir may be deformed and have little merchantable value as

timber, they are more resistant to fungal, insect, and parasitic plant pathogens than

old trees of other species and better protect younger aged cohorts from pathogen

species.

Harvest commercial-quality boughs from lodgepole pine regeneration and any

excess Shasta red fir regeneration.

Rationale: Harvesting boughs reduces leaf area index and generates some income

to cover management costs. These practices reinforce virtually exclusive Shasta red

fir regeneration.

27
Table 6—Objectives, experimental design, hypotheses, and prescriptions for agroforestry systems, stand 401, Diamond Lake

Ranger DistrictObjective Strategies Study design Hypotheses Prescriptions ConstraintsDraw greater revenue from Learn whether matsutake Establish 5 replications Shasta red fir trees spread 1. Retain 60 Shasta red firs Maintain ecosystem processes.high-elevation forests mushroom production depends of 3 treatments and a new matsutake mushroom per hectare, 18 to 50 cen- Conserve species diversity.dominated by Shasta on density control of control plot. Treatments colonies faster to young timeters in diameter at breast Retain amenity values forred fir. overstory trees. differ in the quantity of trees. height, as seed trees; and aesthetics and recreation.

overstory canopy and the 60 trees per hectare, > 50 Provide habitat for highLearn whether one host type of tree regeneration Lodgepole pine trees centimeters in diameter at elevation old-growth wildlife

tree species is favored for and timber products. spread new matsutake breast height, as old-growth species.establishing new matsutake mushroom colonies retention.mushroom colonies. faster to young trees.

2. Retain 60 lodgepole pines

Learn whether volume and Amount of tree canopy per hectare > 10 centimeters intype of organic matter from affects production of diameter at breast height astrees changes soil chemistry matsutake mushrooms seed trees, and 60 Shasta redand inputs of water and solar and the number of new firs per hectare, > 50 centienergy into the soil. colonies. meters in diameter at breast

height.

Learn whether the volume Amount of tree canopyof organic matter affects has a neutral effect on 3. Retain 30 Shasta red firsproduction of matsutake matsutake mushrooms. per hectare, 18-50 centimushrooms. meters in diameter at breast

height as seed trees; and 30Shasta red fir trees perhectare > 50 centimeters indiameter at breast height forold-growth retention.4. Control plot without

. treatment.

Additional option

Choose randomly 2 groupsof 5 management circlesfrom 1 treatment plot. Pilea fixed mass of organic littercollected from 1 group ineach circle in the second group.The remaining 6 circlesserve as controls.

28
Figure 5—Projected stand structure for stand 401 in 25 years.

29
Chip unmerchantable slash and leave slash on site.

Rationale: Slashing unmerchantable lodgepole pine and excess Shasta red fir

reduces competition for growing space among trees and suppresses lodgepole pine

regeneration to favor Shasta red fir. Target species for regeneration are Shasta red

fir (1,200 trees per hectare) and western white pine (250 trees per hectare).

In year 5, harvest Shasta red fir seed trees between 18 and 50 centimeters d.b.h.

Rationale: Seed trees are removed so that treatments in each prescription are

parallel and more growing space is provided for regenerating trees.

Prescription 2: Matsutake mushroom management in uneven-aged stands with

Shasta red fir canopy, lodgepole pine filling gaps, and cohorts of western white

pine—In year 0, retain 60 lodgepole pine trees per hectare with > 18 centimeters

d.b.h. as seed trees. Retain 60 Shasta fir trees per hectare with > 50 centimeters

d.b.h., with 2 to 4 trees per 25-meter-wide management circles as anchor trees.

Rationale: Lodgepole pine is the target regeneration species. Opening the canopy

creates more suitable growing space for lodgepole pine, which can host new

matsutake mushroom colonies.

Harvest Shasta red fir regeneration as Christmas trees, if feasible. Harvest boughs

of natural regeneration of Shasta red fir or excess lodgepole pine stocking.

Rationale: This treatment emphasizes regeneration of lodgepole pine at the expense

of Shasta red fir. Initially, regeneration of Shasta red fir is removed. Additional income

for stand management comes from boughs and Christmas trees from the excess

Shasta red fir trees.

Slash remaining unmerchantable Shasta red fir regeneration to favor only lodgepole

pine regeneration.

Target species for regeneration are Shasta red fir (600 trees per hectare), lodgepole

pine (600 trees per hectare), and western white pine (250 trees per hectare).

In year 5, harvest lodgepole pine seed trees.

Rationale: Western gall rust has infected lodgepole pine trees in the stand overstory.

Continued retention of the overstory trees will increase the chance of passing gall

rust infection to understory regeneration.

In year 15, thin for spacing to leave 40 lodgepole pine for each management circle,

totaling 640 trees per hectare and favoring the most robust trees.

Prescription 3: Matsutake mushroom management in uneven-aged stands with

less dense Shasta red fir canopy, young Shasta red fir filling gaps, and cohorts

of western white pine—In year 0, retain 30 Shasta red fir trees per hectare, with

d.b.h. between 18 and 50 centimeters, for seed trees evenly distributed across the

stand.

Retain 30 Shasta red fir trees per hectare with > 50 centimeters d.b.h., with 1 to 2

trees per 25-meter-wide management circles as anchor trees.

Rationale: Shasta red fir may be the preferred species for natural regeneration, but

densities of overstory retention and seed trees may not need to be as high as in

prescription 1 for suitable tree regeneration and commercial matsutake mushroom

production.

30
Slash and chip remaining unmerchantable Shasta red fir regeneration to favor only

lodgepole pine regeneration.

Leave chips on site.

Rationale: Slashing unmerchantable lodgepole pine and excess Shasta red fir

reduces competition for growing space among trees and suppresses lodgepole

pine regeneration to favor Shasta red fir.

Target species for regeneration are Shasta red fir (1,200 trees per hectare) and

western white pine (250 trees per hectare).

In year 5, harvest all seed trees.

Rationale: Seed trees are removed to avoid infection of young trees and give young

trees space to grow faster.

Plant, per hectare, twice the number of seedlings lacking of target species if natural

regeneration does not meet two-thirds of the targeted amount of regeneration.

In year 15, salvage boughs and slash lodgepole pine and Shasta red fir to reduce

stand density to a maximum 640 trees per hectare (40 trees per management circle)

of the most robust regenerating trees, regardless of species.

Rationale: Spacing affords more rapid growth of remaining trees. By not specifying

how much of each species must remain, the manager has discretion to adapt the

regeneration to site conditions in and around each management circle.

Prescription 4: Control plot—In years 0 through 25, no management is planned.

Harvests of matsutake mushrooms may occur in every year.

Management practices common to prescriptions 1 through 3 are given in appendix 3.

Monitoring

Response Variables

Improving future yields and financial benefits from multiple forest products is contingent on a continuing flow of information from treatment and control plots. The proposed monitoring program assures that quantitative information is collected to support

or refute the assumptions underlying scientific forest stand management. Response

variables include both economic and ecosystem variables (table 7). If none of the

alternatives proves to be economical and cannot attain goals at any time during the

first 25 years, practices need to be reevaluated and redesigned.

Chen and others (1993) stress the importance of continuous monitoring with many

replications among sites, environment, and weather conditions. The monitoring program outlined here, however, assumes little funding will be available and concentrates

on the most critical variables. New information may indicate that omitting or adding

response variables is in order.

Monitoring experimental plots includes mapping locations and densities of production in each harvest season and tracking the rate of creation and spread of selected

colonies for correlation to the age, density, and species of host trees and to local

environmental conditions. Understanding correlations between tree growth and production of matustake mushroom fruiting bodies will be essential to understanding

synergism between timber management and wild edible mushroom management. Of

particular concern is whether trees growing in stands with target conditions described

here will actually grow better than in unmanaged stands. Effects on productivity from

ecological interactions between trees and their mycorrhizal hosts, and matsutake

mushrooms in particular, remain poorly known.

31
Soil temperature, total solar radiation, effective precipitation, and soil moisture in the

A1 (uppermost mineral soil) layer on sites with different treatments require daily, or

even hourly, readings at critical times in matsutake mushroom life history, particularly

at harvest time. These readings can provide valuable insight into short-term and

small-scale factors that produce commercial quantities of matsutake mushrooms.

Data on energy and water energy entering the soil column is critical to test, first,

whether changes in the canopy from tree harvesting or pruning generate the desired

increases in energy and rainfall reaching the ground. Secondly, there is a need to

test whether these increases in energy and rainfall at key times produce the desired

stimuli in the top layer of the mineral soil to increase matsutake mushroom production.

Tree growth in response to management can be tested by measuring leaf area index

and stand basal area. An important question is whether improved growth of trees

actually promotes fruiting of matsutake mushrooms.

Multiple readings at randomly chosen points within treatments plots need to account

for variability within a plot for a more complete understanding of variation within plots.

A minimum of 35 readings per treatment plot is advised.

Table 7—Response variables, techniques for sampling, and response variables

units for management experiments, Diamond Lake matsutake mushroom management area

Response variable Technique Units

Financial variables

Matsutake mushroom production Simulated commercial collection kg/ha

Value of mushroom harvest Recorded mushroom sale tickets US$/ha

Timber harvest Recorded timber scale tickets mbf/ha

Timber harvest value Recorded timber scale tickets US$/ha

Commercial bough harvest Recorded bough sale receipts tonnes/ha

Commercial bough value Recorded bough sale receipts US$/ha

Matsutake cone crop mass Recorded cone sale receipts kg/ha

Value of matsutake cone crop Recorded cone sale receipts US$/ha

Christmas tree sales Recorded sale receipts US$/ha

Ecosystem variables

Leaf area index Light meter readings unitless

Canopy cover Light meter readings unitless

Soil acidity Soil pH meter pH

Soil organic matter Loss on ignition kg ha-1 cm-1

Soil litter depth Random measurement in treatment plots cm

Soil litter mass Dry weight samples of fixed area kg/ha

Soil moisture in autumn Tensiometer g/100 g

Soil nitrogen Kjeldahl g N/100 g

Soil temperature in autumn Hourly thermometer readings in A1 layer °C

Stand basal area increment D.b.h. measurements of tree subsamples m2

•ha-1•yr-1

Matsutake mushroom mycorrhizae Soil cores number/ha

Fungal species diversity Soil cores number of species

32
Opportunistic

Research

Investments in future forest production are susceptible to risks. Climate change and

catastrophic fire, for example, are events that could nullify the best planned management. One form of disaster preparedness is institutional commitment to tracking

response and recovery to human-induced microdisasters. Important information about

matsutake mushroom ecology and the ability of matsutake mushrooms to recolonize

burned sites can be found where slash residue from harvests in the matsutake mushroom management area has been piled and burned. Taken together, the sites furnish

a database for analyzing and developing disturbance response to fire.

Researchers in Japan and Taiwan are already reporting advances in inducing

mycorrhizae in vitro between Asian matsutake mushrooms and both Japenese red

pine (Pinus densiflora Sieb. & Zucc.; Eto 1990) and Taiwan pine (Pinus taiwanensis

Hay.; Hu 1994). Eventual success with similar artificial propagation using North

American matsutake mushrooms and host tree species seems inevitable although

initial efforts have been unsuccessful.4 “Domestication” of matsutake mushrooms

means, of course, that the supply of Asian matsutake mushrooms might grow swiftly.

On the other hand, an increasingly important advantage for the Pacific Northwest in

coming decades is the large base of public forest lands in the Pacific Northwest.

Matsutake mushroom crops from North America’s native forests can meet rising

demand from increasingly affluent eastern Asian countries and contribute even to

world-class tourism targeted to mushroom hunters. The need to research and refine

matsutake mushroom propagation and to plan stand-level culturing trials as management experiments is likely to meet needs of commercial and recreational pickers.

Conclusion The function of the prescriptions presented here is not advocacy for straightforward

implementation of fixed prescriptions. More important to forestry and foresters is

the notion that management for valued matsutake mushroom crops and high-quality

timber is possible; foresters already have the silvicultural tools to implement treatments designed to further the ecological understanding of matsutake mushroom

culture. The reward, of course, can be in terms of the increased revenues from

stands. Not least, though, is the sense of satisfaction for foresters from integrating

research results, personal knowledge about the ecosystems that they manage, and

asking questions to come up with creative and practical adaptive management

experiments suited to the ecological conditions of forests under their management.

Acknowledgments Rick Abbott provided data sets from the Diamond Lake Ranger District; Norman

Michaels, Michael Amaranthus, Philip Sollins, and Bernard Bormann contributed

valuable insight and critique. Funding for this study came from the Demonstration

of Ecosystem Management Options (D.E.M.O.), a multidisciplinary research program

studying the effects of partial overstory harvests on ecosystem processes of National

Forests in the Cascade Range.

4 Personal communication. 1997. Michael Amaranthus,

research forester, formerly with the Pacific Northwest

Research Station.

33
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In year 0, harvest commercial-grade boughs from trees not planned for retention.

Harvest boughs to specified heights on all retention trees.

Rationale: Boughs from trees to be harvested may yield enough commercial biomass

before boles are harvested and thereby reduce slash disposal. Merchantability will

depend on the species composition, demand for specific species, and size of trees.

Unmerchantable biomass is piled and burned away from the site.

Harvest all western white pine, taller than breast height.

Rationale: Eliminating larger western white pines removes trees infected with

western white pine blister rust.

Plant 240 trees per hectare blister rust-resistant western white pine stocks in cohorts

of 15 between matsutake mushroom management circles.

Rationale: Western white pine is the most valuable timber species native to the

research site. Per hectare, 16 cohorts comprised of 15 seedling trees are planted

at 25-meter intervals in the interstices of matsutake mushroom management circles.

Western white pine are managed on a 100-year or longer rotation, with some oldgrowth retention trees eventually left at the site.

Retain nontarget species for stand species diversity as follows:

60 lodgepole pine per hectare and less than breast height, and

60 Pacific silver fir per hecatare and less than breast height.

Appendix 1:

Management

Practices,

Prescriptions 1-3,

Stand 355

38
In year 5, plant per hectare twice the number of seedlings lacking of target species if

natural regeneration does not meet two-thirds of the targeted amount of regeneration.

In year 15 (approximate), harvest boughs up to 1.2 meters high from western white

pine and lodgepole pine trees > 2.4 meters in height to prevent blister rust and gall

rust infection; also prune other species where appropriate according to pruning

guidelines.

Rationale: Pruning accomplishes several benefits simultaneously for stand productivity. First, pruning inhibits infection from blister rust in the lower branches of a tree’s

live crown that lie close to the ground (Russell 1995). Early pruning of young trees

also produces lumber of higher quality at harvest because knot size is reduced in

volume, thus leaving more clear wood volume. Other benefits are the reduction of

leaf area index and resulting decreased leaf litter accumulation on the forest floor.

When canopy and litter interception of energy and water fluxes diminish, matsutake

mushroom production is hypothesized to increase. Comparison with control sites

serves to validate this hypothesis.

In year 25, harvest commercial-grade boughs on trees not planned for retention

as in year zero.

Rationale: Reduction of leaf area index results in less water stress, fewer nutrient

deficiencies, and causes more rapid nutrient cycling.

Harvest trees to meet targets for species retention:

Pacific silver fir—Retain 60 trees per hectare shorter than breast height, giving

preference to open-grown trees.

Western white pine—Retain at least 125 trees per hectare, giving preference to

the best spaced, largest, pruned, blister rust-resistant trees.

Lodgepole pine—Retain 60 trees per hectare taller than breast height, giving

preference to healthy trees with long crown length.

Rationale: Rather than produce a large quantity of small-diameter trees, stand

management early on strives for fewer trees with larger diameters and better wood

quality at harvest. A heavy early thinning to release the most robust western white

pine trees may make additional thinnings unnecessary before the final harvest cut.

Reducing the density of lodgepole pine stands is important to reduce insect and

fungal infestations.

After year 50, harvest all but the most vigorous lodgepole pines.

Rationale: Lodgepole pines will likely not thrive in stands where old-growth trees

and western white pine crop trees are targeted for best growth.

After year 100, harvest western white pine except for 10 trees per hectare of oldgrowth retention trees. Plant western white pine in the same pattern as in year zero,

except that the interstices are offset in a uniform direction by 5 meters.

Rationale: Developing a renewable western white pine resource may take a century

or more to achieve. The value of western white pine trees pruned for high-quality

lumber will likely be comparable with eastern white pine (Pinus strobus L.) and sugar

pine (P. lawsoniana Dougl.) (Fahey and Willits 1995, Page and Smith 1994). Also,

as part of restoration, remnant large western white pine are left on site to confer

old-growth features.

39
Retain Shasta red fir or mountain hemlock trees to develop an enduring overstory

of at least 30 old-growth (i.e., ≥ 50 centimeters d.b.h.) trees per hectare. At year

100, middle-aged western white pine and either Shasta red fir or mountain hemlock

dominate the canopy.

Cut younger trees depending on the composition of the overstory. Stands with

old-growth mountain hemlock will yield some Shasta red fir timber; stands with

just Shasta red fir in the overstory will emphasize cutting mountain hemlock so

that younger cohorts of mountain hemlock can continue to regenerate unaffected

by mistletoe infestations.

Rationale: Continuity in stand density control is hypothesized to extend optimum

conditions for matsutake mushroom colonies. This method is chosen as an alternative that simulates indefinitely midseral stand conditions to promote matsutake

mushroom colonies while permanently retaining old-growth trees.

In year 0, plant 625 trees per hectare of blister rust-resistant western white pine

seedlings on wide (4- by 4-meter) spacing for stand diversity.

Rationale: This enrichment planting raises the potential timber value of the stand

considerably and helps to redirect the stand composition away from dominance by

Pacific silver fir.

In year 0 and following years, spread matsutake mushroom sporocarps on and in

the ground to introduce matsutake mushroom spores for inoculating small trees.

In year 5, plant per hectare twice the number of seedlings lacking of target species if

natural regeneration does not meet two-thirds of the targeted amount of regeneration.

After year 25, the stand uses western white pine to guarantee high-quality timber

production. Lodgepole pine, where present, are harvested after year 75. A few

residual trees function as seed trees around large gaps created by harvests of

midstory mountain hemlock. Long-term uneven-aged management consists of

alternating generations of lodgepole pine or mountain hemlock in the canopy, when

the other species is regeneration in the understory. Given the difference in shade

tolerance between the two species, different methods of regenerating each species

need testing.

In year 0, harvest all commercial-grade boughs from trees not marked for retention.

Rationale: Harvesting of boughs generates some income to offset management

costs, and reduces leaf area index and slash accumulation from harvesting.

Harvest commercial-grade boughs from trees marked for retention, according to

guidelines for pruning in the main text.

Rationale: Reduction of tree leaf area and the amount of leaf litter on the forest floor

is believed important for increasing commercial quantities of matsutake mushroom.

Reduced depth of the organic litter layer can occur by removing leaf litter or by

ensuring that leaf litter decomposes quickly and cycles organic matter into the soil.

Here branch debris is kept from landing on the forest floor of a management circle

and disposed of in a management circle designated for pile burning.

Appendix 2:

Management

Practices,

Prescriptions 1-3,

Stand 357

Appendix 3:

Management

Practices,

Prescriptions 1-3,

Stand 401

40
Harvest all western white pine trees taller than 1.37 meters and retain any naturally

regenerated western white pines less than 1.37 meters tall in all management circles.

Rationale: As a precaution, all western white pine trees greater than breast height

are removed to prevent infection in planted regeneration.

Retain vigorous Shasta red fir trees > 50 centimeters, with up to three anchor trees

per management circles.

Rationale: Old Shasta red fir frequently host matsutake mushroom colonies. Retention of these old trees may allow for spread of matsutake mushroom to other younger

trees growing in the vicinity of old anchor trees.

Plant 240 trees per hectare of blister rust-resistant western white pine stock in the

interstices of management circles

Rationale: Reestablishment of disease-free western white pine is part of a regional

strategy to restore western white pine to its former ecological significance and to

raise the potential value of timber in future harvests. It is also the most valuable

timber species at the Diamond Lake matsutake mushroom research site.

In year 25, harvest from below half of the basal area of all trees between 18 and

50 centimeters d.b.h.

Rationale: Perpetuation of uneven-aged stand composition retains the largest trees

in this diameter class for recruitment as anchor trees if old trees become moribund

or no longer provide matsutake mushroom crops.

Thin western white pine to 80 trees per hectare, retaining the most robust trees in

cohorts of five trees per management circle interstice.

Rationale: This is a release thinning to allow the western white pine to maximize

volume growth on fewer but proportionately more valuable trees. One to two prunings

have already occurred by this time. Spacing between trees of western white pine

cohort ranges between 12.5 and 17.7 meters.

After year 25, the stand emphasizes timber quality and annual matsutake mushroom

harvests under management for joint production. Eventually three diameter classes

make up the stand:

• an old-growth cohort of Shasta red fir retained indefinitely as anchor trees for

matsutake mushroom colonies (>50 centimeters d.b.h.)

• a midsize cohort (18 centimeters < d.b.h. < 50 centimeters) of either Shasta red

fir or lodgepole pine, or both, managed for timber production on long rotations and

as eventual replacement trees for any dying anchor trees

• understory regeneration trees

The content of understory regeneration trees consists of lodgepole pine and Shasta

red fir if the midsize cohort is made up of only Shasta red fir. Otherwise, the understory consists of Shasta red fir alone if the midsize cohort is made up of lodgepole

pine or a mix of lodgepole pine and Shasta red fir. Both planted and naturally

regenerated western white pine occur in this stand. The age class distribution of

western white pine may be uneven, if gaps are colonized by naturally regenerating

western white pine along with the target species.

41
Appendix 4:

Computer Source

Code for

Management

Regimes

Each regime described in this paper is reproduced in QBasic computer source

code for use in modeling with the program MUSHROOM (Weigand 1997). The

nine regimes are reproduced in the ASCII file REGIMES.TXT on the diskette

included with Weigand (1997). Individual versions of the prescription are entitled

with the word “CULTURE” plus specific suffixes that denote first the prescription

number (either one, two, or three) and then the three-digit Umpqua National Forest

stand number (355, 357, and 401) for the pertinent stand for the regime. For example,

prescription no. 2 for stand 357 is found under subprogram CULTURE2357. QBasic

software converts the ASCII-formatted subprograms directly to QBasic source code.

Readers using other computer languages can likewise convert the ASCII text of

the desired prescription into their computer software text editor and edit the text

to conform with the syntax of other computer languages.

42
Weigand, James F. 1998. Management experiments for high-elevation agroforestry systems jointly producing matsutake mushrooms and high-quality

timber in the Cascade Range of southern Oregon. Gen. Tech. Rep. PNWGTR-424. Portland, OR: U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station. 42 p.

Experimental prescriptions compare agroforestry systems designed to increase

financial returns from high-elevation stands in the southern Oregon Cascade Range.

The prescriptions emphasize alternative approaches for joint production of North

American matsutake mushrooms (also known as North American pine mushrooms;

Tricholoma magnivelare) and high-quality timber. Other agroforestry byproducts

from the system are ornamental conifer boughs, pine cones, and Christmas trees.

Management practices concentrate on increasing the physiological efficiency and

vigor of trees, and on altering leaf area index, tree species composition, and stand

age-class structure to increase matsutake reproduction.

Key words: Tricholoma magnivelare, agroforestry systems, nontimber forest products,

adaptive management, Abies magnifica, Tsuga mertensiana, Pinus contorta, Pinus

monticola, Abies amabilis, tree pruning.

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Agriculture is dedicated to the principle of multiple

use management of the 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

management of the National Forests and National

Grasslands, it strives—as directed by Congress—to

provide increasingly greater service to a growing Nation.

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To file a complaint, write the Secretary of Agriculture,

U.S. Department of Agriculture, Washington, DC 20250,

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