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Effect of Harvest Techniques on
American Matsutake
(Tricholoma magnalivelare) Production |
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Joyce Eberhart (1), Daniel Luoma (1),
Dave Pilz (2), Michael Amaranthus (1), Rick Abbott (3), Dan Segotta (4),
and Andy Moore (5) |
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(1) Department of Forest Science,
Oregon State University, Corvallis, OR 975331, USA. (2) USDA Forest
Service, Pacific Northwest Research Station, Forestry Sciences Laboratory,
Corvallis, OR 97331, USA. (3) Umpqua National Forest, Roseburg, OR
97470, USA. (4) Siuslaw National Forest, Florence, OR 97439,
USA. (5) PO Box 1141 Cave Junction, OR 97523, USA. |
INTRODUCTION
The American Matsutake, Tricholoma magnivelare, (Fig.1) is
widespread in North America, but fruits most abundantly in the
Pacific Northwest. The commercial harvest of matsutake is a
multi-million dollar industry with thousands of pickers now
harvesting the mushrooms from private, state, and federal lands.
There is considerable controversy regarding how the resource
should be managed. An important concern is whether raking surface
soil layer to find young mushrooms will reduce subsequent
fruiting. The objectives of this study is to evaluate the effects
of several harvest techniques on matsutake production.
METHODS
In order to asses the effects of harvest method on matsutake
production, six treatments were implemented in two separate
geographic areas of Oregon. The Oregon Dunes National Recreation
Area is along the central Oregon coast. Diamond Lake is in the
Oregon Cascades about 1500m elevation. Both have areas that can
produce large numbers of matsutake. However, each has a distinct
climate regime and forest type. The costal location has a mild
climate, seldom experiences freezing temperatures, and the dry
summer seasons moderated by frequent cool, foggy days. Pinus
contorta, and picia sitchensis are the dominant trees
accompanied a by dense under story of ericaceous shrubs. abies
procera and psudotsuga menziesii dominate the canopy
and the under story is sparse (Fig. 3).Within each of these areas,
3 blocks were established to replicate the experimental
treatments. Shiros (groups of mushrooms that are fruiting from an
underground mat of mycelium, Fig. 4) were identified in 1994 and
treatments were implemented in 1995. Plots were monitored in 1996
and 1997 by recording numbers and dry weight of sporocarps
(mushrooms) from each shiro. Members of the commercial harvesting
community were involved to maintain the integrity of the study
sites. Signs (Fig. 5) and other educational efforts were made to
inform the public of the importance of the study.
The following treatments were implemented, one each on a
shiro in each of the three blocks at the two sites:
1) NH - No matsutake harvest (control)
2) BMP - Best management practice - harvest with minimal
disturbance (gently rocking and pulling)
3) SR-R - Shallow raking of litter layers to the interface
with the mineral soil surface, sporocarp removal and replacement of The litter
4) SR-NR - Shallow raking of litter layers to the interface
with the mineral soil surface, sporocarp removal and NO replacement of the litter
5) DR-R - Deep raking of the litter layers and 10 cm of mineral
soil, sporocarp removal and replacement of litter and mineral
soil
6) DR-NR - Deep raking of the litter layers and 10 cm of mineral
soil, sporocarp removal and NO replacement of litter an mineral soil
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| Fig. 4. Andy Moore reveals a Tricholoma
magnivelare shiro, groups of mushrooms that fruit from a mat
of mycelium and mycorrhizae. Under favorable weather conditions,
shiros produce in the same area annually. |
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FIG. 1. Tricholoma
magnivelare
The American matsutake |
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| Fig. 2. Dan Sagotta demonstrates the deep rake, no
replace (DR _ NR) harvest in dense shrubs at the Oregon Dunes
Recreation Area Site |
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| Fig. 3. Rick Abbott and
Charlie Lefevre inspect a shiro harvested by removal of the litter
layer and 10 cm of mineral soil, without replacement of the litter
at the Diamond Lake site (DR-NR). |
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Charles Lefevre observes the shallow rake
and litter replacement (SR-R) treatment at Diamond Lake
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Fig. 5. Public
education sign installed at a study site |
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RESULTS
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In order to detect treatment effects, we calculated for each
post-treatment year an "expected" sporocarp production
(the predicted number of sporocarps if plots had not been treated).
These predicted values were derived from the percent change in
average production for the no harvest controls for each year, thus
tracking year-to-year variation. The percentage change was then used
to calculate the expected average post-treatment production in
treated plots. The following charts display the comparisons of the
actual sporocarp production to the "expected" production.
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Treatments:
1) NH - No harvest (control)
2) BMP - Best management practice
3) SR-R - Shallow rake, replace litter
4) SR-NR - Shallow rake, no replace
5) DR-R - Deep rake, litter replace
6) DR-NR - Deep rake, no replace
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| Chart 1. Actual vs.
expected matsutake production at the Diamond Lake
study area, 1997 (n =3). |
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Preliminary results at Diamond Lake (Chart 1) suggest that careful
picking has no impact on sporocarp production, nor did a one-time
shallow raking with the litter layer carefully replaced. When
expected numbers of sporocarps were calculated, the actual
production of matsutake on deep rake treatments and shallow rake
without litter replacement were significantly reduced
(p<0.05). Results are only shown for 1997 because fruiting
in 1996 was so limited that the control produced no sporocarps and
expected production could not be calculated.
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| Chart 2. Actual vs. expected matsutake production at the Dunes study area, 1996 (n
=3). |
Chart 3. Actual vs. expected matsutake production at the Dunes study area, 1997 (n
=3). |
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Preliminary results at the Oregon Dunes National Recreation
Area (Chart 2 and 3) suggest that there were initial treatment
effects in 1996 on number of mushrooms produced in the more
severe treatments. The beginning of recovery in production may
be indicated in 1997 |
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DISCUSSION
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| The results were consistent across the two region in that the
BMP and a one-time SR-R treatment were similar to the control. at
Diamond Lake. the more severe treatments (SR-NR, DR-NR) showed dramatic
decreases in sporocarp numbers. We expect that the effects of
repeated raking would be more severe than those reported here for a
one-time raking. The small size of some shirro in the Dunes study
may limit our ability to detect effects, particularly since some
shirros stopped producing mushrooms. However, the initial effect of
the more severe treatments is consistent with the results at Diamond
Lake. There may be interaction effects with shiro size whereby small
shirros are more sensitive to disturbance. The mild costal climate
of the Dunes site may also affect the response of the shirro to
disturbance. |
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