Subject: Does mushroom picking damage or encourage the Mycelium?

From: [email-masked] (Marck D. Pearlstone)
Date: Sat, 11 Nov 1995 12:57:59 GMT

I have long believed that collecting the fruiting bodies of a fungus
would (for many species) encourage the mycelium to fruit more stringly
in future years.

Can anyone confirm or deny this scientifically speaking?

The conservationists are beginning to intrude upon the amateur
(gastro)mycologist in the UK, claiming danger of extinction of some
common species (particularily boletes in the New Forest).

TIA for your consideration of this argument.

Marck D. Pearlstone
[email-masked]

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From: [email-masked] (Lorelei Norvell)
Date: 11 Nov 1995 11:08:46 -0800

> Can anyone confirm or deny this scientifically speaking?

	There are numerous field studies attempting to ascertain the 
answer to this question.  European studies -- particularly those in the 
Netherlands and Norway -- have investigated this, particularly with 
respect to forest management.  Eef Arnolds has found that some 
ectomycorrhizal fungi appear to respond beneficially to a MODERATE amount 
of disturbance.  In Switzerland, Egli, Ayer & Chatelain have monitored an 
area since 1976 and found that there seems to be no deleterious response 
to mushroom harvesting with respect to future productivity.  
	In Oregon the Oregon Mycological Society has been investigating 
whether picking chanterelles has any effect on future productivity -- our 
study was begun in 1986 (with three years for procurement of baseline 
data, and harvesting begun on the experimental plots -- and no harvesting 
on the control plots -- in 1989).  Preliminary data indicate that there 
appears to be no deleterious effect on mushroom fruiting OVER THE SHORT 
TERM.  We shall statistically analyze our data after we have obtained ten 
years of harvesting data.  (The study will be discussed more fully in the 
1995 issue of McIlvainea -- journal of the NOrth AMerican Mycological 
Association -- currently in press.  The article will also contain full 
references of similar studies in Mexico and Europe).
	However, as you know, an ecosystem is a complicated entity, and 
the health of the whole must be considered as well.  The variables 
accompanying any field study -- weather variability is a major problem -- 
make interpretation of data extraordinarily complicated.  But studies are 
underway attempting to answer the impact of harvesting on fungi 
throughout the world.

Lorelei Norvell

---

From: Richard W. Kerrigan <[email-masked]>
Date: 21 Nov 1995 12:54:06 -0500

In addition to picking (in the strict sense), one might consider other 
related impacts (soil compaction, organic horizon displacement, etc.).  
The matsutake research station I visited near Sonobe, Japan, restricted 
foot traffic to well-defined paths which were minimally used.  -- Rick

Lorelei Norvell ([email-masked]) wrote:
: On Sat, 11 Nov 1995, Marck D. Pearlstone wrote:

: > I have long believed that collecting the fruiting bodies of a fungus
: > would (for many species) encourage the mycelium to fruit more stringly
: > in future years.
: > 
: > Can anyone confirm or deny this scientifically speaking?
: 	

: 	There are numerous field studies attempting to ascertain the 
: answer to this question.  European studies -- particularly those in the 
: Netherlands and Norway -- have investigated this, particularly with 
: respect to forest management.  Eef Arnolds has found that some 
: ectomycorrhizal fungi appear to respond beneficially to a MODERATE amount 
: of disturbance.  In Switzerland, Egli, Ayer & Chatelain have monitored an 
: area since 1976 and found that there seems to be no deleterious response 
: to mushroom harvesting with respect to future productivity.  
: 	In Oregon the Oregon Mycological Society has been investigating 
: whether picking chanterelles has any effect on future productivity -- our 
: study was begun in 1986 (with three years for procurement of baseline 
: data, and harvesting begun on the experimental plots -- and no harvesting 
: on the control plots -- in 1989).  Preliminary data indicate that there 
: appears to be no deleterious effect on mushroom fruiting OVER THE SHORT 
: TERM.  We shall statistically analyze our data after we have obtained ten 
: years of harvesting data.  (The study will be discussed more fully in the 
: 1995 issue of McIlvainea -- journal of the NOrth AMerican Mycological 
: Association -- currently in press.  The article will also contain full 
: references of similar studies in Mexico and Europe).
: 	However, as you know, an ecosystem is a complicated entity, and 
: the health of the whole must be considered as well.  The variables 
: accompanying any field study -- weather variability is a major problem -- 
: make interpretation of data extraordinarily complicated.  But studies are 
: underway attempting to answer the impact of harvesting on fungi 
: throughout the world.

: Lorelei Norvell
-- 
Richard W. Kerrigan, Research Department, Sylvan Spawn Laboratory, Inc.		
               1163 Winfield Rd., Cabot, PA  16032  USA
e-mail:	[email-masked]      phone: 412-352-1521      fax: 412-352-4062
	"Success has a thousand parents; failure is an orphan"

---

From: "Robert D. Darby" <[email-masked]>
Date: Wed, 22 Nov 1995 18:42:21 -0800

> foot traffic to well-defined paths which were minimally used.  -- Rick
I have been photographing, creating works of art, culturing, and gathering 
mushrooms for 25 years.  Regarding the matsutake I can testify that 
destruction of the surface areas with such things as garden rakes will 
destroy an area.  When the moss they typically fruit from is raked back 
and left to dry out, they will not fruit until the moss returns taking 
years.  Also the mycelium on the surface is exposed at this time and 
dries out sending god knows what message to the growth below.  They might 
move a few feet away the next year but generally the same army of rake 
preditors will return and rake back further, until there is no moss.  I 
know an area near Seattle where this was done for decades until there is 
no moss at all--nor matsutake.

---

From: [email-masked] (Steven Carpenter)
Date: 23 Nov 1995 14:52:00 GMT

The disturbance by raking for #1, unexpanded, unsurfaced Matsutake 
(Tricholoma magnavelare) has gotten so bad in the Deschutes National
Forest in Oregon that the US Forest Service has even published a handout
in Laotian script to describe the disastrous effects of deep-raking the
forest-floor.  Isolated picking might not be so bad, but the hordes of
people by the hundreds seeking "white gold" will take its toll.  Greed
and ignorance are the main culprits.  The #1 Matsutakes come at such
a high price, that people will destroy the rhizosphere looking for them,
and undoubtedly destroy next year's crop at that site as well.  It 
doesn't take a million-dollar NSF grant to figure that one out (if you
had seen what raking does, you would be convinced; I have heard
trufflers claim that raking doesn't hurt anything, but they also 
haven't published anything to prove that is true!)

I am unaware of any GOOD, published scientific works on the effects of
picking and how different modes of picking may affect local ecosystems or
microenvironments.  There may be some studies going on right now, but
whether they have made it through rigorous statistical analysis and peer
review remains to be seen.  I believe the Germans were doing some work
in the early 1980's, but I haven't seen or sought the references.

-Steven E. Carpenter
 Cascade Research Associates
  & Abbey Lane Laboratory
 [email-masked] 
Robert D. Darby ([email-masked]) wrote:

: On 21 Nov 1995, Richard W. Kerrigan wrote:

: > In addition to picking (in the strict sense), one might consider other 
: > related impacts (soil compaction, organic horizon displacement, etc.).  
: > The matsutake research station I visited near Sonobe, Japan, restricted 
: > foot traffic to well-defined paths which were minimally used.  -- Rick
: > 
: I have been photographing, creating works of art, culturing, and gathering 
: mushrooms for 25 years.  Regarding the matsutake I can testify that 
: destruction of the surface areas with such things as garden rakes will 
: destroy an area.  When the moss they typically fruit from is raked back 
: and left to dry out, they will not fruit until the moss returns taking 
: years.  Also the mycelium on the surface is exposed at this time and 
: dries out sending god knows what message to the growth below.  They might 
: move a few feet away the next year but generally the same army of rake 
: preditors will return and rake back further, until there is no moss.  I 
: know an area near Seattle where this was done for decades until there is 
: no moss at all--nor matsutake.