This time of the
year in the Sea to Sky corridor, with autumn rains fast approaching, results in
the growth of lots of mushrooms in the area’s forests. People often think of
mushrooms as a member of the Plant kingdom, but they belong to a separate
kingdom of organisms called Fungi. The fungal kingdom has been estimated to
contain about 1.5 million species.
Mushrooms
,
yeasts
and
molds
are all examples of
fungi.
Our area boasts
approximately 450 species from the Fungi kingdom. The fleshy, fruiting bodies
of our local mushrooms are used by residents for edible and medicinal purposes,
but these fungi also play a vital role in the health of our local ecosystems.
Different species
of fungi provide different functions in the forest, all as a result of the fact
that fungi lack chlorophyll. Chlorophyll is the green pigment that many plants
use to absorb energy from sunlight in order to make food.
Recalling your
Grade 9 science terminology,
mutualism
is a symbiotic term that describes a close and often
long-term relationship between individuals of different
species
where both derive
a
fitness
benefit. Fungi have a mutualistic relationship with the roots of host plants,
ranging from trees to grasses in our ecosystems. Fungi enhance the plants’
nutrients from the soil while tapping the trees’ store of photosynthetically
generated simple sugars and vitamins.
Myco
means mushroom, while
rhizal
means roots. The collection of filament
cells that grow into the mushroom body is called the
mycelium
. The mycelium of mycorrhizal mushrooms
can either cover the exterior or enter the interior roots cells of the host
plants.
The mycelium also
grow beyond the immediate root zone of the host plant as long, complex chains
of cells that fork repeatedly in matrix-like fashion, spreading over acres to
geographically defined borders. The mycelium can grow over half a kilometre a
day, increasing the plant's absorption of nutrients, nitrogenous compounds, and
essential elements (e.g. copper, zinc, phosphorus). To do this the mycelium
secretes enzymes that break down organic complexes and then absorbs the
newly-freed nutrients through their cell walls. These enzymes and the ability
of the mycelium to selectively absorb materials, results in plants better
protected against bacteria and other contaminants in the soil.
A forest's health
is directly related to the variety and abundance of mycorrhizal fungi and their
hosts. Studies have shown that within the topsoil of a typical Douglas fir
forest in the Pacific Northwest (a.k.a. here!) the mycelium component
approaches 10 per cent of its total biomass, with a cubic centimetre of soil
hosting up to 100 metres of mycelium. Local species of mycorrhizal fungi
include Wooly Chanterelles (
Gomphus floccossus
), Manzanita Boletes (
Leccinum
manzanitae
), Pine
Mushrooms (
Tricholoma magnivelare
)
and Tumbling Puffballs
(Bovista plumbea)
.
Fungi, along with
bacteria
, are the primary
decomposers
of organic
matter in most terrestrial
ecosystems
worldwide. Again recalling that Grade 9 science class, a
saprophyte
is an organism that lives on and gets
its nourishment from dead organisms or decaying organic material.
Saprophytic
mushrooms obtain their food energy
through the decomposition of dead wood and other organic material on the forest
floor and in this process recycle critically limited nutrients back into the
soil.
Most of our gourmet
mushrooms are saprophytic, wood-decomposing fungi. Their mycelium network
weaves between and through the wood’s cell walls, secreting enzymes and acids
they break down large molecular complexes into simpler compounds. The end
result of their activity is the return of carbon, hydrogen, nitrogen, and
minerals back into the ecosystem in forms usable to plants, insects, and other
organisms. Local species such as Oyster mushrooms (
Pleurotus species
), Button Mushroom (
Agaricus
brunnescens
) and Orange
Peel Mushroom (
Aleuria aurantia
)
are examples of saprophytic mushrooms.
So next time you
wander into the local woods looking to harvest or just appreciate the beauty
and complexity of those fruiting bodies of our local mushrooms, you can also
marvel about the world of networks and chemical reactions occurring in the soil
beneath your feet!
Whistler
Naturalist present the Fungus Among Us Mushroom (FAU) Festival,
Oct. 17th and 18th
The FAU is a
two-day event that includes:
• Talks from
experts on mushrooms in the Whistler area;
• A field trip
to local forests with the experts to hunt, collected, label and display
mushrooms;
• A mushroom
cooking (and sampling) demonstration.
Details coming soon!