The chanterelle (Cantharellus cibarius*)—a peek at productivity
LORELEI L. NORVELL, FRANK KOPECKY, JANET LINDGREN & JUDY ROGER
PROCEEDINGS: THE BUSINESS AND SCIENCE OF SPECIAL FOREST PRODUCTS—A CONFERENCE
AND EXPOSITION January 26-27, 1994. Chris Schnepf, ed. Western Forestry and Conservation
Association, Portland, OR. pp. 117–128.
ABSTRACT. Since 1986 the Oregon Cantharellus Study Project team has been engaged in long-
term research of the chanterelle, a commercially harvested edible mushroom associated with
economically significant timber species in the Pacific Northwest. Eight years ago Oregon
Mycological Society members established 10 plots in a 100 year old hemlock-Douglas-fir stand
in the buffer zone of Mt Hood's Bull Run watershed to study whether harvesting chanterelles
adversely affects later fruitings. All chanterelles have been numbered, flagged, measured, and
mapped every 2 weeks throughout the growing season. Since 1989 all chanterelles over 1 cm in
diameter have been removed from 6 of the 10 plots, either by cutting (3 plots) or by pulling (3
pots). No chanterelles have been removed from the 4 control plots. While data reveal a wide
fluctuation of overall productivity -- indicated by biomass as well as numbers of fruiting bodies
-- from year to year, harvesting data fail to show that picking chanterelles has an impact on the
subsequent productivity over the short term. Factors that may influence productivity include
canopy cover, short and long term weather patterns, and the presence of coarse woody debris.
[PDF prepared on October 23, 2016. *The chanterelle referred to throughout as Cantharellus
cibarius is now known to represent the western endemic species, C. formosus.]
Historically, America has been a nation of mycophobes. Until recently, wild mushrooms were
picked only rarely for commercial purposes. However, during the 1980 recession in the Pacific
Northwest, many unemployed forest workers discovered that edible wild mushrooms, essentially
free for the picking on Forest Service lands, could be harvested and profitably sold for export to
Europe and Japan.
Unfortunately this increase in wild mushroom harvesting coincided with several drought
years; as previously abundant wild edibles became difficult to find, recreational mushroom
pickers began to fear overpick with subsequent disappearance of their favorite species. The
knowledge that in Europe—where fungi have been picked for centuries—mushrooms and forests
alike are in decline added to their concern.
One such sought-after mushroom is the yellow chanterelle (Cantharellus cibarius). In the
Pacific Northwest this choice edible lives in mycorrhizal union (from mycorrhiza, meaning
“fungus + root”] with Douglas fir (Pseudotsuga menziesii) and western hemlock (Tsuga
heterophylla). Many mushrooms found on the forest floor are in reality only the tip of a vast
mycorrhizal iceberg; the bulk of the fungus lies underground in an extensive subterranean thready
network called a mycelium. It is this mycelium that extends the root system of the tree, enabling
it to thrive. Most mycorrhizal fungi, dependent upon the nutrients supplied by their mycorrhizal
partners, have not yet been successfully grown in culture. Because growing chanterelles is still
the subject of scientific research (Danell & Fries 1990), if one wants a chanterelle for dinner, one
must find and pick it in the wild.
Unfortunately no one has yet scientifically demonstrated whether picking a chanterelle causes
the mushroom to decline or adversely affect its tree symbiont, although one study (Egli & a.
1990) seems to indicate that harvesting has little effect on the fruiting of various edible
mushrooms. That study needs to be tested by independent research. In North America, there have
been no studies to demonstrate what—if any—effect mushroom harvesting has upon chanterelles.
In 1986 the Oregon Mycological Society—with the support of the USDA Forest Service—
initiated a projected ten-year study to determine whether harvesting the yellow chanterelle would
adversely affect long-term productivity of either the mushroom or its associated trees. Plots were
established in the Mt. Hood National Forest in a stand of 100-year old western hemlock and
Douglas fir located within Portland’s Bull Run watershed Because the site is secured behind
locked gates a relatively short distance from the volunteer work force based in Portland, Oregon,
60 miles away, it is idea for such a long term study.
There are many problems inherent in an experimental study performed in the field. Our first
problem was one of scale: to provide statistically significant data, many plots should be randomly
placed over as large an area as possible. Our study would be small, and we would place plots only
where chanterelles were known to fruit. Despite this, we felt strongly we could make a
contribution—that even a small amount of systematically collected data would in the long run be
informative. Additionally, if we wished to show a causal relationship between harvesting and
productivity, all fruiting bodies from a given mycelium ought to be given the same treatment.
Since chanterelles do not grow consistently in long narrow straight lines, this unfortunately
resulted in variously sized and variously shaped plots—a statistician’s nightmare.
It is not known whether spore influx is necessary for continued viability of the mycelium. If
we assume that it is, then to monitor the impact of sporulation, chanterelles should be removed
from the harvest plots before they begin to sporulate. Data from one study (Largent 1991)
indicate that Cantharellus cibarius produce most spores 14 days after emergence of the fruiting
body. We therefore felt our biweekly visits should be sufficient to remove most, if not all, heavily
spore-producing chanterelles from the harvest plots.
Yellow chanterelles have a long fruiting season—up to five months on our plots—and are
long-lived, with an average spore-producing life span around 40 days (Largent 1991 for C.
cibarius; 49 days cited for Cantharellus lutescens by Kälin & Ayer 1983). Given the long fruiting
season and life span, one might anticipate we would miss or leave behind some chanterelles. We
reasoned that if systematic chanterelle removal for five months each year did not significantly
decrease our chanterelle productivity, careful harvesters (who do not disturb the mycelium or
duff) would probably not threaten their future “crops” either. If, however, our study did reveal a
significant negative impact over time, then further research might determine what harvesting
practices were best.
Furthermore, we did not know whether all of our chanterelle patches represented different
populations or individuals of one population or even whether in fact we were dealing with
Cantharellus cibarius in the European sense. It is possible that the Pacific Northwest chanterelle
may be a different species (the name for this species would be C formosus), but for the time being
dried specimens are needed before final conclusions can be made.
Beginning in September 1986, we established plots in an area where chanterelles were already
fruiting. Ten study plots (ranging in size between 16–64 square meters) were laid out in an
attempt to incorporate only those chanterelles growing from a single mycelial mass per plot.
Each plot was subdivided into 4-m2 quadrats for ease in monitoring. We felt it important to
inventory and monitor accompanying vegetation, ground cover, and associated fungi to provide
baseline biodiversity data. To date 39 vascular plants, 16 mosses and liverworts, and 215 fungal
species have been identified on the OCSP (Oregon Cantharellus Study Project) plots.
The primary aim of the project obviously was studying the chanterelles themselves. Since
1986, 2893 chanterelles have been marked, mapped, and measured on a biweekly basis through
In 1989, after a 3-year baseline period during which no chanterelles were removed from any
of the plots, each plot was designated either a CONTROL or HARVEST plot. Since the plots
grouped themselves into three distinct clusters, we have since designated these three blocks and
South, Northeast, and Northwest. Within each block are located CONTROL, CUT, and PULL plots.
No disturbance nor chanterelle removal is permitted in any CONTROL plot. Beginning in late
July to early August, every fourteenth day during the fruiting season a numbered skewer is placed
next to each new chanterelle, which is mapped by triangulation. Volunteer researchers then
measure and record the diameter, height, and condition of each chanterelle until it disappears or
the season is ended by snow (usually late November or early December.)
HARVEST plots are also monitored biweekly. The same methods are followed except that
chanterelles are removed when above 1 cm in diameter. In the CUT plots, mushrooms are sliced
level with the ground; in the PULL plots they are pulled from the duff. The harvested mushrooms
are then thoroughly dried, weighed to determine biomass, and kept as vouchers in the University
of Washington Fungal Herbarium (WTU) for future molecular analysis.
Preliminary results and discussion
When initiated, our harvesting study was unique in that Cantharellus cibarius productivity
was to be mapped and monitored in both control and experimental plots. The study has been a
labor-intensive one, made possible only by the hard work of over 60 volunteers who have thus far
spent over 5000 man-hours and donated both time and materials to the study. The project is an
unfunded one; we have not yet requested funding but are beginning to recognize the need for
more sophisticated monitoring equipment.
Although we have completed the fifth harvest year of a projected ten-year study, no firm
conclusions as to the effects of picking on chanterelle fruiting or tree growth can be made.
Without a complete statistical analysis, any observations presented here are still tentative.
WEATHER: Any ecological study, involving many uncontrolled variables, is perforce messy. Field
experiments are subject to innate cycles, complex microclimates, and global cataclysms. The
weather, for example, has plagued the OCSP since its inception—with each season varying
considerably from the next. In a study of meteorological effects on sporocarp productivity in
Finland, Ohenoja (1993) notes that temperatures and precipitation during the growth season
explained 19–42% of annual biomass variation and 24–88% of abundance variation (as defined
by numbers of fruiting bodies); the Finnish study also documented that May and July
precipitation was significant for fall fruiting mycorrhizal fungi, with the positive influence
declining by August.
As analyzed thus far in our study, however, the 1986–1993 weather data shown above indicate
little significant correlation between the among of precipitation and chanterelle appearance. (As
plots were being established in 1986 as late as November 11, the appearance of chanterelles is an
extrapolation from previous years and may not reflect the actual initial appearance of chanterelles
that year). Because our study is located in a moist forest zone, it is not too surprising that water is
rarely a limiting factor.
However, our data show significant correlations between average temperatures and chanterelle
abundance. [We have graphed] a significant positive correlation between summer temperature
and seasonal chanterelle abundance: the higher the average summer temperature, the greater the
number of chanterelles.
While monitoring general weather data may help explain much of the variability in annual
chanterelle productivity, we have by no means analyzed all weather relations. Ohenoja (1993)
also noted that high temperatures in the summer months could have a positive effect in fall
fruiting. This may not be related to higher soil temperatures (Kotilova-Kubickova et al. 1990,
Vogt et al. 1992). We have not yet procured ‘sunny day’ data, but it is conceivable that a greater
correlation may be shown between the number of sunny or partly cloudy days and chanterelle
abundance and biomass. During such periods, the chanterelle tree associates would produce
greater amounts of photosynthate, theoretically freeing up more carbohydrates for fungal fruiting.
We have thus far relied on meteorological data obtained from the Bull Run Headworks, which
is five miles to the north and separated by one ridge from the study site. Microclimates will no
doubt prove far more informative; Kotilova-Kubickova et al. (1990) stress the importance of such
micrometeorological factors as soil temperatures at 5 cm depths, daily minimum temperatures
directly above the soil surface, and relative humidity. Due to budgetary constraints, we have not
yet implemented monitoring procedures at this lower (albeit more informative) level.
PULL VS. CUT: In evaluating productivity of a mushroom, both numbers (of fruitbodies) and
biomass must be considered. A few large longer lived chanterelles may produce more spores than
many small ones. In 1991, for instance, substantial spring and summer rains produced 122
chanterelles in A3, a 172% increase over 1990. However, drought stunted sporocarp development
and lowered the amount of biomass, which was 73% of the previous year’s less numerous crop.
Kotilova-Kubickova et al. (1990) note, “the formation of new fruitbodies [of Dermocybe
uliginosa] is preconditioned and initiated by micrometeorological effects on the mycelium. But
the increase in biomass depends mainly on micrometeorological factors acting in the fruiting
period acting during the growth of the fruitbodies.”
Our study is complicated by our inability to weigh chanterelles from the control (i.e. non-pick)
plots directly. Biomass must be somehow extrapolated from data gathered on the harvest plots.
This is more difficult than one might suppose; chanterelles vary from solid compact bodies to
large flowery forms; there appears to be little correlation between number of fruiting bodies and
individual dry weight. Chanterelles that may have the same dimensions (cap diameter, stipe
diameter, stipe length) may have significantly different biomasses, probably a result of different
modes of growth (Kotilova-Kubickova et al. 1990). Furthermore, Vogt et al. (1992) have noted
that there is a potential for “overestimating biomass when life-span is longer than the sampling
interval.” Therefore despite our many measurements, biomass cannot be easily extrapolated. For
that reason we intend to harvest the control plots after the tenth year to acquire baseline biomass
data for the control plots.
Thus far, we have been able to use biomass data only in the harvest plots to evaluate the
differences between cutting and pulling chanterelles. To date, there appears to be little
correlation between harvesting method and productivity. This conclusion supports a similar
finding by Egli et al. (1990), who observed no difference between cutting or pulling on 15 other
edible species (including Cantharellus tubaeformis). If at the conclusion of the study we find no
real difference between cutting or picking, we would suggest pulling chanterelles in future
studies. It is quicker, for one thing, and would also ensure that the entire chanterelle would be
weighed, thereby facilitating biomass extrapolation.
BLOCK COMPARISONS: The small scale of our study required that we investigate potential
variation among the three blocks of plots. While there are differences in abundance and biomass
per square meter among the south, northeast, and northwest blocks from year to year, Figure 5
[not included here] reveals fairly similar trends among the blocks when each was compared to its
own baseline. (1987 was selected as the baseline year because it was the first year all plots were
in place by the beginning of the fall observation period.)
HARVEST VS. CONTROL: Jansen et al. (1985) reported that in some areas in the Netherlands,
Cantharellus cibarius remained locally abundant in traditionally collected areas, apparently in
contradiction to perceived decline in other European countries. After eight years of recorded
observation and five years of harvesting, have we detected any impact on chanterelle productivity
(either positive or negative) in our study?
To answer this question, first we calculated abundance per square meter by dividing the
number of chanterelles by the number of producing subplots (quadrats that have never produced
chanterelles over the past eight years have been deemed “non-producing”). Then chanterelle
abundance in harvest and control plots was compared to 1987 harvest and control baselines. [The
figure above] illustrates the comparison between the combined harvest and control ratios.
While there are differences between harvest and control plots (most noticeably the precipitous
1991 drop in control abundance followed by a 1991 control increase opposed to a steady harvest
abundance decline from 1990-1992), these differences are not statistically significant. There may
be a steady downward trend developing in the harvest plots opposed to continuing ‘undamped’
fluctuation in the controls, but many more years’ data are required before any generalizations
dare be attempted. This does not mean that there is neither negative impact nor positive impact—
simply that no trend one way or another is indicated at this time.
ADDITIONAL COMMENTS—From our intimate association with the study plots, we may permit
ourselves to make the following speculations:
Coarse woody debris and canopy cover appear to be extremely important for
chanterelle fruiting, particularly during extended droughts. Our plots, which contain
a high percentage of both buried and surface wood under closed canopy, appear to
produce mushrooms during times when more open and less cluttered stands remain
empty of chanterelles and other mushrooms.
Visual observations suggest that the yellow chanterelle appears to flourish more in
conservatively managed forest (those ‘high-graded’ or thinned with canopy cover
retained, as opposed to clear-cut) than in old-growth areas. One study (Arnolds
1991) suggests that ectomycorrhizal mycelium benefits from a judicious amount of
disturbance, which observation our data do not contradict.
The fact that some of the mushrooms produced by the mycelia are good edibles
does, however, offer hope to those who would prefer longer timber crop rotations:
current economic studies indicate that harvested mushrooms and other secondary
forest products can bring a greater profit than the trees themselves.
There remain several other questions that require further study before they can be answered.
Mycologists still do not now the average life span of chanterelle mycelia or how to ascertain the
age of a given Cantharellus mycelium. Thus a decrease in productivity on a plot in our study may
reflect nothing more than a natural senescence.
The cyclical nature of chanterelle fruiting should also be investigated. Some apple trees fruit
in alternating years; chanterelles may behave similarly for instance, control plot B5 produced 151
chanterelles in 19990 (our overall best year in all plots) and only 6 chanterelles in 1991 (our
overall second best year in all plots).
There may be complex correlations between tree and fungal productivity. Carbohydrates
produced by the symbiotic union of plant and fungus may be used for cone production some years
at the expense of mushroom production or may influence other competitive fungi.
Additionally there may be little impact on associated trees. Even if picking were shown to
decrease chanterelle productivity, the chanterelle mycelium might continue to exist, providing the
necessary moisture to its plant associates. If the chanterelle mycelium were to decline, the growth
of associated trees may still remain unaffected as other mycorrhizal mycelia assume the function
previously served by the chanterelle.
Further analysis of soils, microclimates, hypogeous fungi, trees, and chanterelle DNA on our
plots may provide some of these answers. We do feel that to comprehend fully the relationship
between harvesting and fungal productivity, a study of more than ten years is needed. Much will
probably remain a mystery. But we are beginning to understand far more than was previously
known about the effect of responsible picking on mushrooms and their associated trees.
We would like to thank OMS volunteers (Preston Alexander, Richard Bishop, Sally Borchman, Louise Brown,
Wanda & Jim Caruthers, Rita Coleman, John Davis, Gordon & Sheryl Ducette, Christel Goetz, Barney Hyde, Tom &
Bette Jones, Chela Kellum, Donna & Ed La Plante, Ed Lipper, Jerry Loehning, Robert Munson, Owen Norvell, Mollie
Peters, Kay & Tom Priest, Debbie Rand, Michael & Scotty Richardson, Maggie Rogers, Sharon Schmidt), other
consultants and volunteers (Joe Ammirati, Michael Castellano, Louise Godfrey, David Goheen, David Lehwalder, Gary
Lincoff, Dan Luoma, Todd Norvell, Scott Redhead, Sherrie Spencer, Thomas Volk, Glenn Walker), USDA-FS
employees (Rex Burkholder, Jim Hadfield, Nancy Halvorson, Dick Hardman, Rex Holloway, Tim Lee, Todd Parker,
Mollie Sullivan, Michael Rassbach, Kathleen Walker), and the City of Portland Water District (Jim Robbins). All have
been interested and generous with their time and advice. Without their effort and support, the Oregon Cantharellus
Study Project would not exist.
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Danell E, Fries N. 1990. Methods for isolation of Cantharellus species and the synthesis of ectomycorrhizae with Picea abies.
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Kälin I, Ayer F. 1984. Sporenabwurf und Fruchtkörperentwicklung des goldstieligen Pfifferlings (Cantharellus lutescens) im
Zusammenhang mit Komafaktoren. MYCOLOGICA HELVETICA 32: 67–88.
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fruiting; II. Fruiting duration and performance; III. Fruit-body growth and biomass production. MYCOLOGICAL RESEARCH 94:
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[distributed at the Conference on the biology and management of wild edible mushrooms in Pacific Northwest ecosystems,
Springfield OR, October 28, 1991].
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Appendix (raw data)
Chanterelle abundance [* control; + pull; $ cut]
Chanterelle biomass [grams dry weight]
Total Precipitation [inches] Mean temperature [°C (annual) (summer)]
1986 70.90 11.9 17.6
1987 58.98 12.3 19.3
1988 77.35 11.5 18.4
1989 69.69 11.3 17.9
1990 74.29 11.5 19.9
1991 79.51 11.9 19.8
1992 65.27 13.1 19.3
1993 As of January 27, 1994, Bull Run headworks weather data were not yet available.