The fungus that makes its home in the forests of Opal Creek is a fundamental component in the life and death of forest organisms, and the recycling of nutrients in our ecosystem. The fungal kingdom is made of organisms that reproduce via spores and are not able to photosynthesize. Fungi is found at every level of the forest from the microscopic species found in the soil horizon, to the gilled mushrooms found in forest canopy soil.
Mushrooms are the fruiting bodies of fungi. When you see a mushroom in the forest, you are seeing the equivalent of an apple on a tree. The fungal “tree” or mycelium is underground or buried in the wood or other substrate to which the mushroom is attached. The mycelium consists of bundles of filamentous cells (hyphae) devoted to absorbing and transporting nutrients. Mycelial mats can be huge, sometimes covering acres. When conditions are right, hyphal bundles will differentiate to form mushrooms. The mushrooms contain specialized reproductive tissues critical for spore production. Fungal sex is unusual and complicated, and a subject best explored on one’s own.
Fungal spores are disseminated in many ways. Most species rely on the small size of the spores, which make them able to be distributed by air currents. Fungal spores have been found in the stratosphere and are a common part of the microscopic organisms found in all natural air samples.
Animals are also responsible for distributing spores by eating the mushroom and then excreting the spores in the scat. Some animals that do this are: slugs, turtles, deer, and flying squirrels. Squirrels and chipmunks also pick up mushrooms, carrying them to trees to dry for future food storage. They are often forgotten and the spores fall to the ground from the tree.
Types of Fungi
The fungus in our forest can be divided into two main categories, the basidiomycetes and the ascomycetes. The basidiomycetes are the fungi that are gilled mushrooms, and in our forest there are estimates of around 3,000 species. The ascomycetes are the cup fungi, the morels, and their allies. Many ascomycetes are in an intimate symbiotic relationship with algae and bacteria species and are known as lichens.
Nutrient Cycling and Relationships
The contributions to the cycling of nutrients provided by fungi are essential. All of the mushrooms found in our forests are wholly or partially saprophytic. This means that they gain their nutrition from dead or dying biomatter. If it were not for the mushrooms and other fungi processing dead material, it would pile up on the forest floor and not be available to the next generation of plants.
Many of Opal Creek’s gilled mushrooms are also involved in an essential intimate symbiotic relationship with plants, and most notably the trees. This relationship is between the roots of the plants and the underground root-like structure of the fungi. This is called the mycorrhizal relationship. Microscopic hair-like fungal hyphae penetrate the roots of the plant and allow for nutrient exchange to take place between the plant and the mushroom. This exchange goes both ways, the plant provides photosynthetically-produced carbon in the form of carbohydrates to the fungus, and the fungus provides essential nutrients such as phosphorous to the plants. The plant also provides water and hormones to the fungus that promote growth.
Mycorrhizal relationships can be complex, as some fungal species will form them with only a single tree species and some individual trees may have many associated fungi. The inability to recreate mycorrhizal conditions is the main reason that some commercially valuable mushrooms (morels, chanterelles, and matsutakes) are difficult to cultivate in a farm environment. Also, tree plantations that lack mycorrhizal fungi grow more slowly and are more susceptible to disease than those where the fungi are present.
Many choice edible mushrooms can be found in the forest of Opal Creek, such as Chanterelles, Matsutakes, Truffles, and Boletes.
Interested in learning more about Fungi?
Check out our weekend workhop on Mushrooms taught in October!