from the The Overstory
#155 - Mycoforestry
Article by Paul Stamets
: NUTRIENT CYCLING
: VALUING BIODIVERSITY
: RECYCLE WOOD DEBRIS FOR
: GUIDING PRINCIPLES OF
: ORIGINAL SOURCE
Without fungi, there are no forests. Mycoforestry is the use of fungi to sustain
forest communities. Mycoforestry can be used to help accomplish the following
* preservation of native forests
* recovery and recycling of woodland debris
* enhancement of replanted trees
* strengthening sustainability of ecosystem
* economic diversity
Mushrooms contribute phosphorus and confer other ecological benefits to the
riparian and forest ecosystems. Mushrooms become launching platforms for
explosive growth of bacterial populations, many of which are critical for plant
health. Mushrooms have a preselecting influence on the bacteria sharing their
habitat (Tornberg et al. 2003). Bacteria beneficial to trees regulate inputs and
outputs of nitrogen and are phosphorus limited (Sundareshwar et al. 2003).
Mycelium absorbs phosphorus from its surroundings, moving these mineral salts
over distances, and later releases this mineral when mushrooms rot or the
mycelium dies. Fungal-decomposing bacteria then absorb the phosphorus. As the
mushrooms rot, the ecosystem benefits from this cycling of essential minerals in
which the bacteria allow phosphorus, zinc, potassium, and other minerals to be
redeposited back into the nutritional bank.
In other words, mushroom remains fertilize the ecosystem. Other organisms
quickly consume the dying and rotting mushrooms. As plants grow, their falling
leaves, branches, and flowers enter into fungal cycle of decomposition. This
response - a highly energized state of regrowth - is nature's safeguard for
rapid, adaptive habitat renewal. After catastrophes strike, the saprophytes lead
the way toward renewal, supporting the construction of complex life-supporting
Reforestation efforts are greatly enhanced when mycorrhizae are introduced to
sprouting seeds or to the roots of young trees before or at the time of
planting. The value of fungi is being increasingly recognized when economists
assess forests. Many researchers sincerely believe that secondary products from
woodland ecosystems, in addition to the other benefits they offer, provide
strong economic incentives to leave the forests intact. And beyond short-term
economic incentives, forests affect climate and prevent desertification. Placing
an economic value on an aesthetic - for instance unspoiled landscapes, an
incalculable like biodiversity, or undiscovered mycomedicines - confronts the
simplistic conclusions of conventional economic models that compare timber and
mushrooms as two mutually exclusive commodities. From an economic perspective,
many biologists believe the biosphere is underappreciated.
Taking into consideration high-value mushrooms such as matsutake, the economic
benefits of preserving the woodlands increasingly outweighs the short-term gains
of logging, assuming the economic ratios remain on par. A study by Alexander et
al. (2002) using a Soil Evaluation Equivalent (SEV) formula found that, in south
Central Oregon, a comparison of harvesting timber and matsutake mushrooms
yielded close to the same economic benefit from the land over the same time
period. This evaluation, however, does not factor many other positives in not
cutting the timber - enriching soils, reducing erosion, helping the health of
streams, increasing biodiversity, improving air quality, effecting regional
cooling (thereby offsetting global warming) and, some particularly incalculable
aesthetics: the experiential pleasure a person or family has in the pursuit of
wild mushrooms while walking through verdant natural landscapes. In fact, wild
mushrooming, according to a United Nations report by Eric Boa (2004), has
worldwide socioeconomic significance.
Selective harvesting of developing second- and third-growth forests, however,
when done with the intention of preserving other secondary forest products such
as mushrooms, may prove to be the best practice for sustaining profits. These
principles are the cornerstone of an emergent new management strategy called
The manner in which mushrooms are harvested, too, has a dramatic impact on
subsequent crops. For instance, a study in southern Oregon showed that when
matsutake patches were raked and the divots from the harvested mushrooms were
not recovered with duff, matsutake crops in subsequent years plummeted 75-90
percent; if harvesters recovered the divots after shallow raking, yields were
not adversely affected (Eberhart et al. 2003). Similarly, no adverse effects
were noticed over a decade of harvesting chanterelles in a forest west of
Portland, Oregon (Pilz et al. 1993, 2003), where the preferred practice was to
cut the mushrooms while picking, leaving the stem butts undisturbed. We now know
that chanterelles often come up in pairs, and if harvesters cut only one
partner, then the other mushroom, often hidden from view as a resting
primordium, can grow to maturity. Perfecting harvesting practices to protect
future harvests dramatically improves the profitability of the
mushroom-harvesting industry. We can't yet accurately assess the value of our
old-growth forests, but the valuations continually increase directly in
proportion to our knowledge. If a mushroom species exclusive to the old-growth
forest prevents a viral epidemic that could kill millions and cost billions, how
do we value it? Mushroom species producing enzymes to break down VX toxin and
antibiotics protecting cells from pox and HIV viruses dramatically increases the
value of old-growth forests. Losing these antiviral species in order to improve
the quarterly reports of lumber companies may cost our civilization far more in
economic terms than it gains for a single industry: the future of our species
may literally be at stake.
RECYCLE WOOD DEBRIS FOR FOREST
After loggers haul trees away, vast debris fields remain behind: stumps, brush,
and downed small-diameter or otherwise unmarketable trees. Until this wood
debris decomposes, its biomass is locked away from the food web and is therefore
unavailable to bacteria, protozoa, insects, plants, animals, and other fungi,
some of which would dismantle the cellular structure of wood, freeing nutrients.
In order to stimulate decomposition and trigger habitat recovery, we can
selectively introduce keystone mushroom species such as saprophytic fungi, the
first species to feed on dead wood.
Making wood debris fields more fungus friendly speeds up decomposition and helps
the decomposition cycles become more balanced. To help nature recalibrate after
logging, fungi must be brought into close contact with the dead wood so that the
forest floor can act as a springboard for saprophytic and other fungi, which are
instruments of the forest's immune system, ready to heal its wounds. For several
years after a forest has been cut, the mycosphere survives underground, with an
increasing loss of diversity over time unless plant communities and debris
fields are renewed.
In forestlands, mycelium follows trails of fallen wood. Sticks and branches
making ground contact are soon consumed by mycelium from existing fungal
communities. From the ground, mycelia literally reach up into the newly
available wood. Whether wood is whole or fragmented affects the rate at which
nutrients return to the soil: wood chips are quickly consumed by fungal
mycelium, whereas logs decompose much slower. I recommend creating a matrix by
chipping wood into variably sized fragments in order to let mycelium quickly
grab and invade the wood. Wood fragments with greater surface areas are more
likely to have contact with spores or mycelium; this is especially true in the
cultivation of mushrooms where spawn growth is integral to success. The fungal
recycling of wood chips lessens reliance on fertilizers, herbicides, and
pesticides. So leaving the chips in the woods helps recovering forest soils just
like leaving stubble on farmed land helps agricultural soil. However, if the
wood is reduced to too fine a dust and piled too deeply, it suffocates aerobic
fungi, including beneficial saprophytes, and anaerobic organisms flourish; chips
should be no smaller than 1/8 inch and piled no more than a foot deep.
GUIDING PRINCIPLES OF MYCOFORESTRY
Mycoforestry is a newly emerging science, an off-shoot of ecoforestry practices
with an emphasis on the role of beneficial fungi. As with any new scientific
path, guidelines help steer the course of research and the development of new
implementation strategies. The guiding principles I foresee are:
1. Use native species of fungi in the habitats needing restoration.
2. Amplify saprophytic fungi based on available wood substrates.
3. Select species known to help plant communities.
4. Select mushroom species that attract insects whose larvae are food for fish
5. Select fungal species according to their interactions with bacteria and
6. Choose species that compete with disease rot fungi (such as Armillaria
species and Heterobasidion annosum) by using mycorestorative saprophytes like
Hypholoma, Psilocybes, Trametes, Ganoderma, Sparassis, and allies.
7. Choose species of known medicinal or culinary value if economically valuable
mushrooms help tilt the balance in favor of preservation.
8. Promote ground contact with fallen trees so they can reenter the soil food
9. Leave snags to sustain bird and insect populations.
10. Use spored oils in chain saws, chippers, and cutting tools so that wood
debris is immediately put into contact with fungal spores, speeding up
11. Retain wood debris mass on site, and place debris around newly planted
trees, along roads, or wherever erosion control is needed.
12. Only burn wood debris as a last ditch measure for disease control.
13. Use mycorrhizal spore inoculum when replanting forestlands. (Seedlings
cultivated in pasteurized or constructed soils on tree nurseries typically lack
Figure 1. <http://www.agroforestry.net/images/Stametsmf1.jpg>
or <images\Stametsmf1.jpg> In the ancient
forests carpeting Mount Rainier, I encountered a large noble fir
(Abies procera) hosting a noble polypore (Bridgeoporus nobilissimus) at its
Figure 2. <http://www.agroforestry.net/images/Stametsmf2.jpg>
or <Stametsmf2.jpg>Piles of branches sit
undecomposed after 20+ years on a farm on the border of Mason and Thurston
counties, Washington State. Had this wood been chipped, placed into contact with
the ground, and/or shaded, saprophytic fungi would have flourished, and debris
by-products would have reentered the food chain. Brush piles like this one also
pose a fire hazard, since the elevated wood dries, hardens and resists rot.
Figure 3. <http://www.agroforestry.net/images/Stametsmf3.jpg>
or <Stametsmf3.jpg> Left: Young Doulgas fir
seedlings without wood chips. Right: Young Douglas firs seedlings collared with
wood chips. The addition of wood chips cools the ground, increases moisture
retention, and provides delayed release nutrients as they decompose.
Alexander, S. J., D. Pilz, N. S. Weber, E. Brown, and V. A. Rockwell.
2002. Mushrooms, trees and money: Value estimates of commercial mushrooms and
timber in the Pacific Northwest. Environmental Management 30(1):129-141.
Boa, E. 2004. Wild edible fungi: A global overview of their use and importance
to people. Rome, Italy: Food and Agriculture Organization of the United Nations.
FAO Technical Paper: Non-Wood Forest Products 17.
Eberhart, J. L., D. L. Luoma, D. Pilz, M. P. Amaranthus, R. Abbott, and D.
Segotta. 1999. Effects of harvest techniques on American Matsutake (Tricholoma
magnivelare) production. Proceedings from the IXth International Congress of
Mycology. Sydney, Australia. <http://www.matsiman.com/formalpubs/harvestmethodposter/harmethposter.htm>.
Pilz, D., R. Molina, and L. H. Liegel. 1998. Biological productivity of
chanterelle mushrooms in and near the Olympic Peninsula Biosphere
Reserve.Ambio-A Journal of the Human Environment. Special Report Number 9,
Pilz, D., L. Norvell, E. Danell, and R. Molina. 2003. Ecology and management of
commercially harvested chanterelle mushrooms. Portland, Ore.: USDA Forest
Service, Pacific Northwest Research Station. PNW-GTR-576.
Tornberg, K., E. Baath, and S. Olsson. 2003. Fungal growth and effects of
different wood decomposing fungi on the indigenous bacterial community of
polluted and unpolluted soils. Biology and Fertility of Soils 37:190-197.
Sundareshwar, P. V., J. Morris, and E. Koepfler. 2003. Phosphorus limitation of
coastal ecosystem processes. Science 299:563-565
reprinted from the Overstory #155 with permission of the author:
Stamets, P. 2005 (in press). Mycelium Running: How Mushrooms Can Help Save the
World. Copyright ? 2005. Ten Speed Press, Berkeley, CA. For more information: <http:www.fungi.com>.