Download Role of fungi in forests If all the fungi were removed from our Pacific

Role of fungi in forests
If all the fungi were removed from our Pacific Northwest Forests how would that change
our forests? (brief but thorough)
Fungi are fundamental to the success and health of every terrestrial ecosystem, and essential to
the sustainability of biodiversity.
The ability of fungi to decompose major plant components - particularly lignin and
cellulose - is the basis of their organic recycling role. Without decomposer fungi, we would
soon be buried in litter and debris. They are particularly important in litter decomposition,
nutrient cycling and energy flows in woody ecosystems, and are dominant carbon and organic
nutrient recyclers of forest debris.
Fungi are particularly valuable in acid soils, where the low pH makes it difficult for the
survival of other organic decomposers such as bacteria. Bacteria release nitrogen in the
form of nitrate which is easily leached from the soil and therefore lost to surface roots.
However, the fungi that break down the organic surface litter release nitrogen into the
soil in a form of ammonia nitrate which is less mobile. This could be very important to the
successful establishment of young trees and to the sustainability of the ecosystem as a whole.
The transformation of nutrients and their transition from soil into plants is an essential
component of ecosystem nutrient cycling which could not be achieved without the fungi.
Mycorrhizal associations' form fungus-root systems which are far superior to roots
alone. Many of the world's plants are partnered by mycorrhizal fungi, both in natural
ecosystems and in agricultural or forestry crops. The fungi have a mutually beneficial
relationship with the plants, thanks to a two-way exchange that occurs in modified roots known
as mycorrhiza, (literally 'fungus-roots').
Fungi need a constant supply of organic matter to survive and thrive. The nutrient cycle relies
on the reintroduction of dead material to provide a constant source for the fungi to decompose.
In an existing woodland the organic horizon is topped up each year with falling leaves, but in
our parks and gardens, or on new plantings schemes, this source of nutrients is either
nonexistent or is removed as overenthusiastic gardeners remove all the autumn leaves.
Fungi perform a number of essential functions in forest ecosystems and are an important forest
resource. The following list is certainly not exhaustive, but includes functions for consideration
when making forest management decisions.
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Mycorrhizal associates - Mycorrhizal fungi form mutualistic symbioses with
host plant roots, increasing plant water and nutrient uptake in exchange for
carbon (for reviews see Allen 1991, O’Dell et al. 1993, and Smith and Read,
1997).
Pathogens - By killing trees, pathogenic fungi can reduce or eliminate plant
species, cause gaps in the forest canopy that may increase plant species diversity
(Holah et al. 1993), and add to accumulation of dead wood. As a consequence
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of altering plant diversity, pathogenic fungi in turn alter the fungal community
(Christensen 1989). Other pathogenic fungi such as heart rot fungi, while not
true tree killers, and have an influence on nutrient cycling and wildlife habitat
(Hennon 1995).
Decomposers – Wood and litter decay fungi recycle carbon, minerals, and
nutrients for use by other organisms, and contribute to the soil matrix physical
properties. Fungal fruiting bodies are a major agent of nitrogen, phosphorus and
potassium export from logs, particularly in the early stages of decomposition
(Harmon et al. 1994).
Wildlife food sources - Fungi provide an important food source for many
species, including microbes, arthropods, nematodes, and mammals (Fogel and
Trappe 1978, Maser et al. 1978, Ingham and Molina 1991).
Edibles and medicinals – The harvest of edible and medicinal fungi, including
chanterelles, morels, matsutake, boletes, truffles, ganoderma (reishi) and others
is a growing industry, particularly in the Pacific Northwest (Molina et al. 1993,
Schlosser and Blatner 1995, Amaranthus and Pilz 1996, Pilz et al. 1998). In
addition, recreational mushroom collecting has become increasingly popular in
the past several decades.
Effects:
If all the fungi were removed from our Pacific Northwest Forests, then the consequence
will be
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Biodiversity will not be maintained, forest ecosystem will loose the sustainability in
biodiversity.
Decomposition of dead particles will not be occurring in the great extent, so
nutrient cycle will affected.
pH of the soil may change, and that will affect the growth of the other plants.
Pathogenic fungi will change the biodiversity of the forest ecosystem.
Mecinal fungi produce valuable medicines to us. If there are no fungi in Pacific
Northwest Forest that will affect the medicinal industry present near by.