Mushrooms

	From the damp ground of the forest floor sprout tiny umbrellas. We call these mushrooms, although the real work is going on under the ground, unseen. In the Pacific Northwest we have the ideal warm and moist climate to produce hundreds of different kinds of mushrooms. In fact, the west coast of North America may be the best place on earth for mushrooms. Mushrooms are the above ground fruiting bodies of an organism called a fungi. The fruiting bodies come in a wild variety of colors, shapes and sizes.

Questionable Stropharia	Bears Head mushroom	Lobster Mushroom

Fungi are made up of a microscopic set of cob-web like material called mycelia. Imagine if you had a giant iron and could squish an apple tree into a large, flat, one cell thick layer. The apple tree would expand in size and spread out over hundreds of feet. Then imagine this is buried in the top 6 inches of soil and the apples start popping up out soil when they grow. This is pretty much how a fungi works. The underground part may stretch for hundred of feet in all directions, in fact in some places, it has been learned that this underground network forms the largest living thing on the planet, stretching out for hundreds of acres. If you want to see this part of the mushroom in person, take a board, and lay it on the ground under some trees where leaves have fallen. After about 5 or 6 weeks, if you turn the board over you will find it covered with the white spider-web looking material of mycelia.

As this material grows and expands it forms tiny nodules. These are tiny fruiting bodies, mushrooms. When it begins to rain, these tiny mushrooms absorb water like a sponge and rapidly expand, often growing so fast that they expand more than 1,000 times in 6-12 hours.

The mycelia, a white, cobwebby looking material

The roles of fungi: decomposer

Fungi interact with the environment in several ways. The majority of fungi break down dead material into nutrients that other organisms can use. The mycelia produce chemicals that are especially good at breaking down other materials and releasing important nutrients. They also do this very quickly, and a fallen leaf may be recycled into nutrients in only 3-4 weeks. Fungi are critical components of the ecosystem, and coupled with bacteria and insects, recycle all dead matter over time.

Fungi also interact with bacteria in ways that we are only just beginning to understand. The chemicals given off by mycelia in some cases stimulate and help certain kinds of bacteria to grow, and also, at the same time, kill other types of bacteria which compete or eat the bacteria the fungi is helping. Under the soil is a very complex chemistry, of which fungi are key players.

Rhytisma punctatum, an ascomycete growing on a maple leaf.

The role of fungi: mycorrhizae

In the Pacific Northwest the dominant trees are conifers. One of the advantages that these trees have is that they form a partnership with mushrooms. The roots of the tree end in tiny hairs which do the work of absorbing water and nutrients from the soil. The fungi mycelia connect to the tiny tree root hairs and the fungus mycelia network then delivers nutrients to the trees roots. Since fungi are exceptionally good at breaking down complex molecules into simple ones, they increase the trees ability to gather nutrients. The fungi also produce chemicals which kill off bacteria which might harm the tree. In exchange, the tree gives the fungi sugar from photosynthesis which the fungi uses to expand itself. This relationship is known as mycorrhizae. Many kinds of plants utilize fungi in this way. For trees this is especially critical during the first few years of life. When the seedling tree first gets established, its need for water and nutrients is often greater than its tiny root system can produce. During a summer drought, most seedling conifers do not have the ability to meet their needs for water alone and will die. Those that form the mycorrhizae parternship with fungi are much more likely to survive the first few dry summers.

A root hair with mycelia attached

The role of fungi: Parasites

The third role of fungi is that they eat or attack living things, sometimes even killing them. There are many kinds of parasitic fungi. Athletes foot or ring worm are common ailments caused by parasitic fungi. Fungi like the lobster mushroom at the top of the page parasitize other mushrooms. The mushroom to the left is a common mushroom called the Honey Mushroom. It sometimes acts as a decomposer, breaking down dead wood from trees. However it also can act as a parasite, particularly attacking tree roots and sometimes killing many trees. Armillaria root rot is a common tree disease, and there are many others which infect trees, shrubs and fruit. A common problem with commercial blueberries is called mummy berry, which is a fungus that infests and ruins blueberries.

Fungi are a source of both food and medicines. There are many people who make their living in the northwest growing or collecting mushrooms for market. The total cash value of wild mushroom harvests was over a billion dollars in the late 1990's. Certain prize species of mushrooms can fetch several hundred dollars a pound and there has been growing concern about the impacts of unregulated mushroom harvests on public forest land. The most famous medicinal mushroom is penicillin, a drug which kills bacteria. There are actually many mushrooms that act as anti-bacterial agents, and medical researchers have begun to isolate chemicals and medicines from over 300 mushroom species.

Mushrooms ability to break down chemical substances have led to experiments in using mushrooms to clean up toxic waste spills, oil spills and other contaminated sites. In a recent test, a mushroom application completely cleared up a toxic chemical spill over three months. Completely. There was no measurable trace of the chemical contaminant on the site where the mushrooms had been applied! The mushrooms apparently broke down the contaminate into other harmless elements.


Strobilurus kemptonae specializes in decomposing old Douglas fir cones	Bracket fungi decompose a standing tree

Some basics about mushroom identification

The fruiting bodies of fungi come in a variety of shapes, colors and sizes. In simplistic terms, you could divide mushrooms into two groups, those shaped like umbrellas and those not. The mushrooms shaped like umbrellas have a stem and a cap. The underside of the cap will have either gills, teeth or look like a sponge. The purpose of mushroom is to produce spores, tiny dust like reproductive cells. A key component of identifying many mushrooms is the color of the spores.
By placing a mushroom cap on a sheet for a few hours you can collect a sample of the spores, which you can then use to determine the spore color.		Like all fields of study, mushrooms have their own terminology which describes attributes of the mushroom. The cap and stem of the mushroom need to be examined carefully for the attributes. The best way to learn this terminology is to spend a few hours with some mushrooms and a field guide. You may not successfully figure out the mushroom in hand at first, but you will begin to learn the terms and what to look for. An important consideration is where the mushroom is growing. Some mushrooms grow in meadows, in forests, on the ground or on logs or wood.
		The mushroom to the left has a long stem, and a ring on the stem. The cap was stout and white with a tinge of brown. It had pinkish colored gills when it was young, and brown as it aged, and it had chocolate brown spores. The mushroom smelled faintly of almonds and was found in a grassy meadow area. All these characteristics combined enabled the student to determine it was a mushroom of the genus Agaricus. This is the same genus as the common grocery store mushroom.

Thanks to Mike Beug for permission to use some of his pictures. For an over view of mushrooms in the NW click Here