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A Total Forest Management Plan
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This is a unit about some of the plant life under the ground. Part of this world is discussed as roots, the other as mushrooms. That over simplifies the situation for there are many types of fungi (some 240 species in Montreal, Canada, see Natel and Neumann 1992) and probably other plants under the surface. The emphasis is on understanding all of the volume of the land.
One major component of the life is the ectomycorrhizal fungi. These (pronounced "my-co-ri-zi") are the small white, thread-like structures under the ground. They attach to pines and oaks and feed there (and to other fungi) but they are not parasites. They have a mutually beneficial relationship for they act as little roots and feed the plants water and nutrients. The trees obtain their phosphorus and nitrogen from the fungi; the fungi obtain energy (simple sugars) from the tree roots. They enhance the ability of trees to absorb water and nutrients from the soil and they move photosynthetic carbohydrates from trees into the soil. In turn, this carbon supports a vast array of insects, nematodes, bacteria and other organisms in the soil.
Mycorrhizae Marx (1979) provided basic information and background on the ectomycorrhizae.
Although most workhas been with pine seedlings, the benefits of ectomycorrhizae may be as great for artificial regeneration of oaks as they are for pines.
" Ectomycorrhizae occur naturally on many important forest tree species around the world. All members of the gymnosperm family Pinaceae (pine, spruce, fir, larch, hemlock, etc.) as well as certain angiosperms (willow, poplar, aspen, hickory, pecan, oak, birch, beech, eucalypt, etc.) normally form ectomycorrhizae. Ectomycorrhizal infection is initiated from spores or hyphae (propagules) of the fungal symbionts inhabiting the rhizosphere of the feeder roots. propagules are stimulated by root exudates and grow over the feeder root surface and form a fungus mantle. Following mantle development, hyphae develop around root cortical cells and form the Hartig net. These hyphae may completely replace the middle lamellae between the cortical cells. The Hartig net is the main distinguishing feature of ectomycorrhizae. Ectomycorrhizal roots may be unforked, bifurcate, multi-forked (coralloid), nodular, or in other shapes. The color of an ectomycorrhiza is determined by the color of the hyphae of the fungal symbiont and may be brown, black, white, red, yellow, or blends of these colors. Individual hypha or strands of hyphae may radiate from the fungus mantles into the soil and to the base of the fruit bodies of the fungi.
"Most fungi which form ectomycorrhizae with forest trees are Basidiomycetes that produce mushrooms or puffballs (fruit bodies). [See below.] Certain Ascomycetes such as truffles also form ectomycorrhizae, however. Over 2100 species of these fungi can form ectomycorrhizae on trees in North America. The fruit bodies of these fungi produce billions of spores that are widely disseminated by wind and water. Most ectomycorrhizal fungi are dependent on their hosts for simple carbohydrates, amino acids, vitamins, etc., necessary to complete their life cycles. Ectomycorrhizal development, therefore, is a prerequisite for fruit body production by these fungi; not all fungi which form mushrooms and puffballs, however, are ectomycorrhizal. Many of these fungi are saprophytes that play important roles in the decomposition of organic matter and the mineral cycle in forest ecosystems. Certain other fungal species are pathogenic to trees.
"Many species of fungi are normally involved in the ectomycorrhizal associations of a forest, a single tree species, an individual tree, or even a small segment of lateral root. As many as three species of fungi have been isolated from a single ectomycorrhiza. Even as a single tree species can have numerous species of fungi capable of forming ectomycorrhizae on its roots, a single fungus can enter into ectomycorrhizal association with numerous tree species. Some fungi are apparently host specific; others have broad host ranges and form ectomycorrhizae with members of numerous tree genera in diverse families. Fecal extracts from flying squirrels and chickarees have been shown to support growth of nitrogen-fixing bacteria also found in the feces of forest rodents. These bacteria continue to live after freezing.
"Ectomycorrhizal fungi aid the growth and development of trees. For some trees, such as Pinus, they are indispensable for growth under natural conditions. Trees with abundant ectomycorrhizae have a much larger, physiologically active, root-fungus area for nutrient and water absorption than trees with few or no ectomycorrhizae. This increase in surface area comes both from the multi-branching habit of most ectomycorrhizae and from the extensive vegetative growth of hyphae of the fungus symbionts from the ectomycorrhizae into the soil. These extramatrical hyphae function as additional nutrient and water absorbing entities and assure maximum nutrient capture from the soil by the tree host. Ectomycorrhizae are able to absorb and accumulate nitrogen; phosphorus, potassium, and calcium in the fungus mantles more rapidly and for longer periods of time than nonmycorrhizal roots. It is also thought that ectomycorrhizal fungi help break down certain complex minerals and organic substances in the soil and transmit nutrients from these materials to the tree. Ectomycorrhizae also appear to increase the tolerance of trees to drought, high soil temperatures, soil toxins (organic and inorganic), and extremes of soil pH caused by high levels of sulfur or aluminum. Ectomycorrhizae deter infection of feeder roots by pathogens, such as species of Pythium or Phytophthora. Hormones either induced or produced by fungal symbionts cause ectomycorrhizal roots to have greater longevity (duration of physiological activity) than nonmycorrhizal roots.
"Two other types of mycorrhizae also occur on plants; endo- and ectendo-mycorrhizae. Endomycorrhizae are most prevalent. They occur on many important hardwoods (elms, gums, walnut, sycamore, maples, ash), most agricultural crops (cereals, peas, beans, corn, forage crops), and most ornamental and horticultural plants. Ectendomycorrhizae are rare."
Specific ectomycorrhizae formed in the nursery can be used to improve survival and growth of pine seedlings on various sites. When there is a need for artificial oak regeneration, treating seedling roots may increase survival and growth.
Foresters have been able to able to manipulate and reasonably manage three species of fungi in pine nurseries--Pisolithus tinctorius, Thelephora terrestris, and Cenococcum graniforme. All three fungi have been associated with various oak species in the field. Pisolithus has been proven to be or is suspected to be ectomycorrhizal with ten species of oak. There are genetic differences in the oak species in forming these ectomycorrhizal relations. White oak seems most easily (best) innoculated.
These two preliminary studies proved that techniques developed for inoculum production, soil infestation, and seedling root assessments of pine have application to oak seedlings. Certain isolates of Pisolithus were found to be superior
The best known of these Ascomycete fungi are the "truffles." They are below-ground (hypogeous) relatives of the cup fungi. They have developed a spore-dispersal strategy that depends on animals. As a truffle matures, it begins to emit an odor, a chemical signal that a feast awaits. Only a few of the several hundred are pleasing to human taste (Trappe and Castellano 1991)These fungi fruiting bodies are excellent food for many animals. The animals spread the spores through the soil, another major but poorly understood relationship (Maser et al. 1978). The trees are highly dependent on a working matrix, a network of mycorrhizae, to consistently gain water and nutrients for growth. Thus they are dependent up on a mass of distributors, the small rodents. This link of trees and wild animals has be ignored. It will one day be evident that a healthy community of small rodents within a forest contributes mightily (via their role in "managing the forest floor and root complex") to site index, probably more than 5 % in advanced ages. The financial worth of rodents can be estimated (if that is ever needed) by the change in wood volume actually and potentially available from the same site with and without such rodents.
Carey (2004) noted that flying squirrels also consume non-truffle foods and thus can forage far from trees and in areas with brush and hardwood species (with foods) and thus disperse mycorrizhal fungi ... and thus increase truffle diversity associated with forest diversity.
Cork and Kenagy (1989) found that hypogeous fungi have high concentrations of nitrogenous compounds, vitamins, and minerals and are a major dietary item for many rodents. Surprisingly, 80% of the nitrogen in samples was in the indigestible spores and indigestible walls of the peridium and only half of the remaining 20% was protein nitrogen. They suggested that the food value of the fungal resource was derived from its timely great abundance and strong odors. Such features of the plant result in high energy and nutrient yields for the mammals in relation to foraging effort.
Another major link occurs. The rodents have truffles as a major food; the rodents are major prey of owls and other raptors.
Fires can reduce the mycorrhizae and thus it is essential to understand soil conditions and the life processes of the fungi to minimize the harmful effects and allow maximum recovery. Grigal and McColl 1977) reported no difference in the weight loss of litterbags (used in soil decomposition studies) placed before and after a fire in Minnesota.
Toxic substances can influence the fungi as well as can acid rain (but this may be a positive effect since fungi typically grow well in acid conditions.)
Natel and Neumann (1992) found that seeking fungi based on vegetation classification missed species. Their occurrence was poorly correlated with observed vegetation.
Productivity (e.g., Cantharellus sp. in the Pacific Northwest) can be highly variable as well as is the price and thus harvesters are wary of more regulations, higher permit fees, and contracts that restrict harvesting to those who may the highest price for rights to pick in certain areas. (The situation is similar to beaver trapping.) Resource managers must sell permits and collect fees to cover the costs of administering harvests. Vandalism to machinery and property, potential liability claims, and illegal waste dumping can force any landowner to restrict their property to pickers. Pickers may form large groups to bid on contracts for picking mushrooms. Information, planning, and soliciting help in studies can improve the relations with and allow funds from mushroom pickers to add to the profits of an area.
Timber is only 1 to two orders of magnitude more valuable than mushrooms, "yet while timber grows, harvesting mushrooms can provide annual income to harvesters once fruiting is established." (Pilz et al. 1998)
See New York Biological Garden's fungal type collection catalog of the Ghent University Herbarium, Belgium.
See Soils
Literature
Cork, S.J. and G.J. Kenagy.1989. Nutritional value of hypogeous fungus for a forest-dwelling ground squirrel. Ecology 70(3):577-586
Grigal, D.F. and J.G. McColl. 1977. Litter decomposition following forest fire in northeastern Minnesota. J. Appl. Ecol 14: 531-538.
Liegel, L., D. Pilz, T. Love and E. Jones. 1998. Integrating biological, socioeconomic, and managerial methods and results in the MAB mushroom study. AMBIO special report, Sept.,p.26-33
Marx, D.H. 1979. Ectomycorrhizae:Rx for Artificial regeneration of oak?, Proc. 17th Hardwood Symposium of the Hardwood Research Council, Cashiers, NC. p. 66-71.
Maser, C.,J.M.,Trappe and R.A. Nussbaum 1978. Fungal-small mammal interrelationships with emphasis on Oregon coniferous forests. Ecology 59:799-809.
Nantel, P. and P. Neumann. Ecology of ectomycorrhizal-basidiomycete communities on a local vegetation gradient. Ecology 73 (1): 99-117
Pilz, D., F.D. Brodie, S. Alexander, and R. Molinda. 1998. Relative value of Chanterelles and timber as commercial forest products. AMBIO special report 9, Sept. p.14-16
Trappe, J.M. and M.A. Castellano 1991. Keys to the genera of truffles (Ascomycetes) McIlvainea 10:47-65.
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