De La Bastide, P. Y., B.R. Kropp, and Y. Piche

• 
  These results provide evidence that a single genetic individual of L. bicolor can remain associated with a host root system for at least 3 years and vary significantly in spatial distribution.
  
• 
  The different patterns of sporophore occurrence observed for various ectomycorrhizal species and host-fungus combinations suggest differing requirements of the fungi for host genotype, root types, and soil/microclimatic conditions.
  

• 
  [This study] investigated the species richness of ectomycorrhizal fungi based on epigeous sporocarps in an Interior Cedar-Hemlock forest in northwestern British Columbia.
  
• 
  Ectomycorrhizal fungal richness, based on epigeous sporocarps, decreased exponentially as gap size increased.
  
• 
  The most likely reason for these findings is that the removal of the tree bole during harvest eliminated or reduced the supply of carbon to the fungus. It is well known that hyphae form a mycelial network that links the roots of neighboring trees…Creation of above-ground gaps through tree harvesting or natural disturbance can create below-ground gaps in this hyphal network.
  
• 
  These data support findings from other studies that moisture extremes limit the number of ectomycorrhizal fungi producing sporocarps. Moisture, along with reduction or elimination the carbon resource (additional references cited), temperature (additional references cited), soil nutrient levels (additional references cited) and forest floor removal (additional references cited) can affect the abundance and number of fungal species producing sporocarps.
  
• 
  These results confirm the importance of sampling both sporocarps and root tips to achieve an accurate estimate of the ectomycorrhizal fungal community in forest ecosystems.
  
• 
  A significant gap in the below-ground ectomycorrhizal hyphal network occurs when above-ground gaps of 900m² or greater are created. This has implications for both management of edible mushrooms and wildlife, and for the mycorrhizal colonization of regenerating seedlings. The number of types of sporocarps, including edible types for humans and small mammals, decreases in larger gaps.
  

• 
  The purpose of this study, carried out at a subalpine forest in British Columbia, was to investigate the effect of three different clear-cut sizes: 0.1, 1.0, and 10 ha., on the persistence and diversity of ectomycorrhizae.
  
• 
  Because the mycorrhizal association may be particularly important at high-elevation sites where the growing season is short and soil nutrient resources are limiting, management practices that maintain this inoculum source may improve the success rate of tree establishment at these locations.
  
• 
  In conclusion, tree removal resulted in a dramatic decline in fine root activity and a similar reduction in the diversity of mycorrhizae two growing season after logging and a virtual elimination after 3 years.
  
• 
  …the observation that diversity declined with distance from the forest edge implies that smaller cut blocks will retain a higher diversity of mycorrhizae as they have a greater perimeter to area ratio than larger cut blocks.
  

• 
  Individual mycorrhizal fungi may colonize just a few root tips or may be able to span between roots and trees, persisting in larger areas of forest through the life of the stand. (Dahlberg & Stenlid 1990)
  
• 
  Size of selected individuals: (citations for each in Table 2, p. 257)
  

1. 
   Litter fungi: 1-150m (Tricholomopsis can be 150m).
   
2. 
   Root decay fungi: 30- 635 m (Armillaria can be 635m).
   

• 
  Some genets of root-rot fungi continue mycelial growth for centuries, with life spans extending across tree generations. Such species generally can survive extended periods saprobically until roots of new host trees contact old infected roots and the fungus can resume its expansion.
  

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  This study was undertaken to provide a preliminary estimate of the impact of varying amounts and kinds of soil organic matter on ectomycorrhizal development in mature western Montana forests.
  
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  Decayed wood was significantly more effective than humus in large quantity...but amounts greater than 45 % were not beneficial. Conversely, humus was more effective than decayed wood in low quantities.
  
• 
  Forest management decisions with potential to disturb soils and reduce woody residues, particularly in the dry northern Rocky Mountain habitat types, should take into consideration the importance of soil organic reserves and their effects on ectomycorrhizae as a factor in forest soil quality. A consistent effort should be made to retain a moderate quantity of large woody materials.
  
• 
  Preliminary estimates indicate that approximately 25-37 tons/hectare, 14cm in diameter or larger, of fresh residues should be left after harvesting and prescribed burning to provide parent materials for the decayed soil wood…
  
• 
  A quantity of organic matter in excess of these requirements, particularly on moist sites, can be considered as much of a potential problem for ectomycorrhizae as too little.
  

• 
  The present study was conducted to evaluate if microbial processes and decomposer fungi were sensitive to manual or chemical vegetation management, in addition to harvesting and site preparation.
  
• 
  Four treatments were established on three sites that had been clearcut and site-prepared 2 years prior to the initiation of the study:
  

2. glyphosate herbicide (Vision)

3. triclopyr (Release)

4. manually operated brushsaws

• 
  The present study demonstrates that further disturbance of the harvested sites as a consequence of manual and chemical vegetation control also has negligible effects on decomposer fungal communities and decomposition or mineralization processes 2 years after disturbance.
  
• 
  Conclusions:
  

2. Fungal community structure….was not altered 2 years after vegetation management was carried out on a clear-cut and prepared forest soil.

• 
  This study was conducted to evaluate the effects of wildfires on ectomycorrhizal fungal communities in Scots pine stands.
  
• 
  Below-and above-ground communities were analyzed in terms of species richness and evenness by examining mycorrhizae and sporocarps in a chronosequence of burned stands in comparison with adjacent unburned late-successional stands.
  
• 
  Recent investigations have revealed that the results of Sporocarp surveys poorly reflect the composition of below-ground ectomycorrhizal fungal communities (additional references cited).
  
• 
  Our data suggest that the influence of fire on communities of ectomycorrhizal fungi in boreal forest in Sweden differs in several respects from effects reported in previous studies of ectomycorrhizal fungi conducted in other forest ecosystems. For example, the number of ectomycorrhizal species recorded …did not change following fire. To the contrary [additional references found] that wildfire decreased ectomycorrhizal species richness in jack pine forests in Canada. Fires in these Canadian studies were of high intensity and not only killed the stands but also strongly altered the ground vegetation and humus conditions.
  
• 
  The significance of the fire intensity is supported by a study of a prescribed, low-intensity burn in northeast USA which left most trees alive, only slightly affected the litter layer, and hardly affected the fruiting of ectomycorrhizal basidiomycetes.
  
• 
  In conclusion, (this) study suggests that low-intensity wildfires of Swedish boreal forest have less effect on the ectomycorrhizal fungal species composition than are caused by spatial variation. Most of the common ectomycorrhizal fungal species tended to be found at all sites in the fire chronosequence and species richness did not seem to be affected by wildfire.
  

• 
  These preliminary results indicate that populations of arbuscular mycorrhizal fungi can rapidly increase following restoration thinning in Northern Arizona ponderosa pine forests. This may have important implications for restoring herbaceous understory of these forests because most plants depend upon arbuscular mycorrhizal associations for normal growth.
  
• 
  The specific objectives of this study were to: (1) quantify the effect of restoration thinning on arbuscular ectomycorrhizal and ectomycorrhizal fungal propagules densities; and (2) assess the relationships between mycorrhizal fungal propagules densities and soil and plant community properties.
  
• 
  These preliminary results indicate that mycorrhizal fungal population densities respond rapidly to restoration thinning in northern Arizona ponderosa pine forests. Two main processes control population densities of mycorrhizal fungi following disturbance: immigration of new propagules from nearby areas and survival and spread of residual propagules.
  
• 
  Finally, recent mycorrhizal fungi research in a variety of environments has show that mycorrhizal interactions may be important determinants of plant diversity, ecosystem variability, and productivity (additional references cited).
  

• 
  Live trees within forest disturbances could support refugia populations of ectomycorrhizae fungi from which to reestablish ectomycorrhizae communities during forest succession.
  
• 
  The effectiveness of refuge paper birch trees in maintaining a forest ectomycorrhizae community on birch seedlings, both in clearcuts and forest in northwest British Columbia, was examined.
  
• 
  Refuge trees were effective in maintaining forest ectomycorrhizal communities, but the mix of early-stage and multi-stage fungi also demonstrated how this ectomycorrhizal community was well adapted to disturbances, at least in these small clearcuts.
  
• 
  The current British Columbia biodiversity guidelines, which outline targets for refuge tree density and diversity across varying scales of landscape disturbance, should facilitate the recovery of ectomycorrhizal communities after harvesting.
  

• 
  The dependence of ectomycorrhizal fungi on tree hosts means forest management operations, such as harvesting, thinning, and fertilizing, will directly affect ectomycorrhizal mushroom abundance and species composition (additional references cited).
  
• 
  Study noted a negative correlation with western redcedar (a nonhost tree species) and ectomycorrhizal fungi.
  
  1. 
     Colonization of roots for many ectomycorrhizal species, especially late-stage types, is more effective by hyphal contact between root systems than by spores.
     
  2. 
     With many nonhost trees in a stand, the contact between root systems of host trees would be reduced…
     
  3. 
     Partial cutting that favors retention of a diverse mix of ectomycorrhizal tree species over western redcedar may benefit ectomycorrhizal mushroom richness.
     

• 
  Partial cutting systems could allow some timber removal without necessarily reducing ectomycorrhizal mushroom communities. Harvesting prescriptions that can retain some stand basal area with good tree vigor would be one option to accommodate commercial timber and mushroom resources.
  

• 
  The chemical substrates in mycorrhizal fungi often stimulate the growth and nitrogenase activity of the associated N₂ fixers.
  
• 
  Associated N₂ fixers are producers of plant-growth-promoting substances and B-group vitamins.
  
• 
  Other microbes in mycorrhizal fungi have capacities to break down primary minerals, thereby releasing nutrients available for uptake by plants.
  
• 
  Land restoration can be achieved by planting trees with nitrogen-fixing and rock weathering capacities, such as alders and some pines.
  
• 
  Changes in tree species compositions on site are likely to alter below-ground processes through changes in functional processes of organisms.
  
• 
  Trees with different types of microbial associations can have significant impacts on biogeochemical processes, affecting recovery of degraded ecosystems and forest sustainability.
  

• 
  A survey of the patterns of wood decaying fungi as to occurrence of sporocarps on naturally fallen logs of Norway spruce (Picea abies) was undertaken in two nearby forest stands with different histories of management.
  
• 
  One stand was an old-growth forest with few signs of logging and the other stand was selectively logged 60-80 years ago.
  
• 
  Forest management had a negative impact on species diversity. Newly fallen and weakly decayed logs in a natural forest had a higher species richness, more red-listed species, as well as more indicator species compared to similar logs in a managed forest.
  
• 
  The importance of dead wood for species diversity of wood-inhabiting fungi was clearly demonstrated.
  

• 
  Ectomycorrhizal formation, survivability, and physiognomic characteristics were assessed for conifer seedlings encountered 1 and 2 years postfire in the Huck burn site near Grand Teton National Park.
  
• 
  The number of ectomycorrhizae was positively correlated with the number of primary needles and root/shoot ratio. These results highlight the importance of mycorrhizae to conifer seedling survival during the initial growing season and point to alteration of carbon allocation as a primary mechanism affecting seedling survival.
  
  1. 
     Seedling survivability could be affected by increasing carbon allocation below ground, resulting in increased water uptake and decreased transpirational losses during early development.
     

• 
  It is abundantly evident that mycorrhizal colonization during the first growing season is a critical process affecting the survival of conifer seedlings. Seedlings that survived into the second growing season had all formed mycorrhizae by the end of the first growing season.
  

• 
  The objective of this study was to examine soils known to contain basidiospores of both hypogeous and epigeous ectomycorrhizal fungi and sclerotia over time to gain some insight into persistence of these propagules in the soil.
  
• 
  This study concludes that basidiospores and sclerotia of ectomycorrhizal fungi persist in the soil for at least 2 years. How long these propagules remain viable under field conditions and the relative importance of one propagules type over another are yet to be determined.
  

• 
  See especially “Conservation and management of forest fungi in the Pacific Northwestern United States: an integrated ecosystem approach. (R. Molina, D. Pilz, J. Smith, S. Dunham, T. Dreisbach , T. O’Dell and M. Castellano).
  

• 
  Small-scale gap disturbances, marked typically by the disappearance of between 1 and 10 trees from the canopy, have demonstrable effects on nutrient conservation and mobilization in soils (additional references cited). However, there is a paucity of information, especially regarding the dynamics of fine-root recolonization following gap formation.
  
• 
  Below-ground responses to above-ground disturbance were studied in experimental gaps created in a 95-year old Pinus contorta stand in southeastern Wyoming.
  
• 
  Active root tip densities remained high around single dead trees and declined with increasing gap size to near-zero values in the 30-tree gaps…
  
• 
  The results suggest that a mesoscale root gap had been created with the death of 30 trees, but it could not be determined clearly from the present investigation which of various-sized gaps represented a threshold.
  

• 
  Pre-fire fungal flora (polypores and corticoid fungi ) of 284 dead trees, mainly fallen trunks of Norway spruce, was studied in 1991 in an old, spruce-dominated mesic forest in southern Finland. Species diversity of the pre-fire fungal flora was very high, including a high proportion of locally rare species and 4 threatened polypore species…
  
• 
  …the whole area was burned. Burning was very efficient and all trees in the forest stand were dead one year after the fire. Also, the ground layer burned almost completely.
  

1. 
   Fire destroys the mycelia or decreases the inoculum potential of many fungi by consumption of dead woody material and by creation of extreme environmental conditions (additional reference cited).
   

• 
  Greatest losses in species numbers occurred in moderately and strongly decayed trees, in coniferous trees and in very strongly burned trees. Fungal flora of non-decayed and slightly decayed trees, deciduous trees, and slightly burned trees seemed to have survived the fire quite well and in these groups the species numbers had increased slightly as compared with the prefire community.
  
• 
  Species favored by fire were mainly ruderal species, which can utilize new, competition-free resources created by fire, and species that have their optima in dry and open places also outside forest-fire areas.
  
• 
  In the tree trunk the conditions (e.g. moisture) for mycelial growth and fruiting are more constant than in the ground (additional references cited)..this is probably the most important reason why fruiting seems to be more constant in wood-rotting fungi than in mycorrhizal or litter-decomposing macrofungi.
  
• 
  In disturbed areas, it is usually the ruderal species that should increase their numbers at the cost of competitive species. Ruderal species are typically characterized by effective dispersal and germination, rapid uptake of nutrients, and rapid mycelial extension. They are ephemeral, non-competitive, and have a rapid and often total commitment to reproduction (additional references cited).
  

• 
  Mycophagy may play a particularly important role in the life cycle of hypogeous-ectomycorrhizal fungi. Mycophagous animals potentially disperse spores of these fungi when they defecate on the forest floor, where spores may establish mycorrhizal relationships with roots of conifers.
  
• 
  Loss of mycophagous mammals from coniferous stands could affect long-term functioning of those stands and their ability to respond after disturbance.
  
• 
  Loss or decline of hypogeous fungi after anthropogenic disturbance, which has been documented in several studies, may have consequences for diversity of small mammals and persistence of vertebrate predators that depend on a mammalian prey base.
  
• 
  Management plans that enhance persistence of less obvious forest components, such as hypogeous fungi and small-mammal communities, are equally likely to ensure long-term conservation of forest habitat.
  

• 
  From size (highly variable, 1m-15ha) and persistence of genets (individuals of a given genotype), conclusions about the relative role of vegetative spread vs. spore establishment of ectomycorrhizal fungi can be drawn.
  
• 
  Field experiments conclude that certain ectomycorrhizal fungi appear early in the successional sequence, and are a major component of disturbed systems. Others dominate later stages of succession.
  
• 
  Early colonizing species typically colonize by spores, and appear to have small nonpersistent genets.
  
• 
  Later successional species colonize initially by spore but then spread primarily from hyphal networks.