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!