The Blue Mountain Forest Health Report - Gast et
al. states that:
"Numerous factors directly and indirectly influence the potential for mycorrhiza formation, including seedling physiology, environmental conditions, and abundance of soil microorganisms and propagules (Perry et al. 1987). Modification of these conditions may influence a seedling's ability to form mycorrhizae. Mycorrhizal potential following disturbance such as clearcutting and slash burning depends primarily upon (1) the balance between mortality and input of mycorrhiza-forming propagules (such as spores and hyphae of mycorrhizal fungi); (2) the recovery of host plants, which provides the energy to stabilize populations of mycorrhizal fungi and allows them to grow and colonize nonmycorrhizal roots of surrounding plants; and (3) the diversity of fungus species, which buffers the mycorrhizal community against environmental changes following disturbance." (from Long-Term Forest Productivity and the Living Soil by M. P. Amaranthus, J. M. Trappe, and R. J. Molina)
Productive ecosystems tend to retain more nutrients. Although succession occurs, nutrients are increasingly immobilized in forms that are less available for plants and animals, such as phytates, lignins, tannins, and humic and fulvic acids. In order for nutrients to become available once again to plants and animals, they must be mineralized by the interaction of decomposers, i.e., bacteria and fungi, and their predators, i.e., protozoa, nematodes, microarthropods, and earthworms. These populations and their interactions are important to ecosystem stability, including predator-prey interactions, mutualisms, and disease.
It is perhaps something of a conundrum that in healthy ecosystems, while nutrient cycling and productivity increases, nutrient loss is minimized. This is possible because of the increasing complexity of the soil foodweb. As total ecosystem productivity increases, biodiversity within the soil foodweb also seems to increase. The greater number of interactions of decomposers, their predators, and the predators of those predators, the fewer the losses of nutrients from that system. Without the soil foodweb, plants would not obtain the nutrients necessary for growth, and the aboveground foodweb would not long continue. In undisturbed ecosystems, the processes of immobilization and mineralization are tightly coupled to plant growth, but following disturbance, this coupling is lost or reduced. Nutrients are no longer retained within the system, reducing the productivity of the ecosystem and causing problems for systems into which nutrients move, especially aquatic portions of landscapes.
Thus, the soil foodweb has been suggested as a prime indicator of ecosystem health. . . . Soil organisms play critical roles in maintaining soil health and fertility (Coleman 1992). The roles these soil organisms play include: (1) decomposition of plant material . . . (2) immobilization of nutrients in soil by bacteria and fungi . . . (3) soil aggregate structure improvement, which increases water-holding capacity, clay surface interactions with nutrients, and plant root architecture; (4) alteration of the soil pH; (5) mineralization of nutrients . . . and (6) control of disease-causing organisms through competition for resources and space, control of soil micronutrient status, and alteration of root growth.
Among factors that keep plants from growing at their maximum potential rate, nitrogen is usually the limiting factor. Especially in forests, nitrogen limitation, not light limitation, is what restricts productivity. For sub-dominant canopy trees, light may be the current limitation, but it is quite probably that competition for nutrients from the soil initiated that sub-dominant tree's inability to compete for light.
Is the suggestion then to spread tons of chemical fertilizer on forest stands? This is not a reasonable solution. First, spreading fertilizer throughout forests of the United States would be prohibitively expensive. Secondly, commercial fertilizer is often not incorporated into the forest, but lost through erosion and through the soil profile into the groundwater. This problem is seen with row crop agriculture, where fertilizer is applied to the soil, but soil and the organisms that perform processes in soil, can't retain that added nitrogen. In some cases, added fertilizer acts as a biocide, killing soil organisms and further degrading the soil. Thus, addition of chemical fertilizer may not be wise. It's much wiser to manage the soil and soil organisms appropriately, applying fertilizer only when it is critically needed to prevent the loss of a critical ecosystem component.
If we understand nutrient cycles in the soil, and work to enhance those processes that are beneficial to the vegetation human beings want on that land, we can enhance and encourage nutrient availability for the plants we desire during the time of year those plants require massive amounts of nutrients. We can enhance and encourage nutrient retention in soils, during those times the plants we desire in the system don't need those nutrients. Instead of fighting the complex soils system that has developed through eons of time, we need to learn what is present in soil, and how to manage those organisms. Instead of destroying nutrient cycling processes and the organisms that perform those processes for us, we need to sustain them.
There are current management practices that clearly work against the established nutrient cycling processes. In order to understand why these processes are detrimental, the first step is to understand what maintains soil health. Mainly, it is soil organisms that are responsible for the processes that provide soil nutrients. These organisms are different in different soils. In fact, the information being gathered suggests that the vegetation in a system is determined by what soil organisms originally colonize a soil and how those organisms cycle nutrients. The development of soil relies on feedbacks, where soil organisms provide the nutrients for plants to grow, and plants provide the carbon inputs, the organic matter, that select for and alter the soil organism communities. One influences the other, and both determine the trajectory of succession.
Forest succession can be changed by altering the organisms in the soil.
Most conifers are obligately mycorrhizal; conifers can be grown in hydroponic systems without mycorrhizae, but when they must compete with other plants for nutrients, conifers such as Douglas-fir, ponderosa pine, or lodgepole, won't survive without the mycorrhizal fungi growing on their root systems.
This mycorrhizal network is destroyed when soil is compacted with large machinery, and mat-forming mycorrhizal fungi are destroyed when forests are clearcut. A number of pesticides, including some herbicides, kill these fungi. The system is severely set back by many current management practices. Perhaps it would be wise to modify our management so that the biomass of these organisms isn't severely reduced. Certainly recovery of the system would be much more rapid, and less likely to follow some other successional trajectory, if the organisms responsible for healthy soils were not so severely affected.
. . . In forest systems, fungi are dominant soil microorganisms, the dominant decomposers. There can be up to 600 km of fungal hyphae per gram of soil in an ectomycorrhizal mat, and, on average, forest soils contain a kilometer of fungi per gram of soil. If fungal fruiting bodies are considered, such as mushrooms, fungal pathogens, and fungi growing on bark, leaves, and branches, fungal biomass can rival tree biomass in a mature or even old-growth forest.
One of the major functions of decomposer fungi and bacteria in soil is to retain nutrients in the soil when it rains. If applied pesticides kill bacteria, the nutrient-retaining ability of that soil is reduced. If fertilizers are applied that select for bacteria instead of fungi in forests, fungi can be outcompeted, soil pH can be increased, soil aggregation can be altered, and the forest can be lost. The ratio of fungal to bacterial biomass is critical. . . . Thus, in forest soils, we must maintain a fungal dominance in order to maintain favorable environment for the trees. If bacteria become the dominant form of soil decomposer, grasses are selected and the forest can be lost.
In fact, in experiments being performed in the Olympic Peninsula and in southern Oregon, it has been shown that if the fungal component in soil is lost, then regeneration of conifers becomes impossible. And it is the loss of the fungal component that triggers the resulting lack of regeneration. In fact, work done in Tasmanian eucalyptus forests suggests that the overstory trees will be lost if the fungal component of the soil is lost. So understanding this ratio of fungi to bacteria is critically important. . . .
In the foodweb model, there are higher-level predators in the system, and their function is to prevent the predators of bacteria and fungi from becoming too numerous, and to serve as food for even higher-level predators. The mites, predatory nematodes, and other microarthropods are all eaten by organisms that spend more of their time aboveground. So third, fourth, and fifth trophic-level predators are eaten by spiders, millipedes, centipedes, beetles, and insect larvae. These organisms are eaten by birds, voles, shrews, and can even comprise an important portion of the diet of bears or fox.
Thus soil organisms are extremely important in a number of ways. If we lose parts of the belowground organisms, the system doesn't function as it should. If the predators in the system are lost, the pools of mineral N in the soil are lost and plant growth suffers. . . . Competition for already occupied niches, both in terms of space and resource availability, can prevent an added organism from getting a foothold or finding a niche in most cases. But if the system is disturbed, insulted, or abused, then the added organism may find resources and space. Once successfully occupying a niche, that organism will be much more difficult to delete. In addition, genetically engineered soil organisms, whose parent strain occupies a normal soil niche, may do quite well when added to soil despite the presence of large numbers of other organisms.
In summary, the soil foodweb is a prime indicator of ecosystem health for a variety of reasons. If soil processes are disrupted, if bacterial or fungal activity is decreased, if fungal or bacterial biomass is decreased, if the ratio of fungal to bacterial biomass is altered to something inappropriate to the desired system, if the number or diversity of protozoa is reduced, or nematode numbers and nematode community structure is altered, loss of natural vegetation or even human health can be predicted. An understanding of soil foodweb structure and function as disturbance occurs could be extremely useful for assessing ecosystem health. Interpretation of the meaning of effects following specific disturbances still needs to be assessed. From Natural Resource News Jan. 1995 - Organisms in the Soil: The Functions of Bacteria, Fungi, Protozoa, Nematodes, and Arthropods by Elaine R. Ingham, Dept. Botany and Plant Pathology, Oregon State University
Other nutrient studies, such as one by Sterba (1988) found that residual trees had 12% greater growth if felled trees remained on site than if they had been removed. In assessing nutrient mass balance, one must consider belowground pools, rock weathering, atmospheric inputs, and biological processes such as nitrogen fixation (Waring and Schlesinger, 1985). Wiedemann (1935) found that several decades of litter raking is Scots pine plantations on sandy soils in eastern Germany led to higher soil densities and to growth declines of nearly two site classes. Similar results were found for radiata pine in New Zealand (Dyck and Skinner 1990).
Logging projects must examine the importance of large
down and underground wood in providing for late season moisture and providing
the major source of nitrogen in this type of site. According to Dr. Allen
Harvey a presenter in the recent seminar on soils produced by the BMNRI:
Total soil organic content generally reflects site productivity. Organic matter in the forest floor, including soil wood and surface mineral horizons, usually make up less than 15% (by volume) of the top 30 cm of soil. Normally, however, this 15% has the highest concentrations of nutrients (especially N), has a substantial cation exchange capacity, and supports most N-fixing and ectomycorrhizal activities. This uppermost 15% is also the part of the soil most likely to be disrupted or destroyed by forest management activities. Deeper soil horizons can be important to tree growth, especially on dry, sandy soils, but it can be subjected to compaction by heavy equipment.
Traditionally, some have viewed soil as inert and inanimate, and soil properties have been perceived as distinctive but relatively unchanging, except for plant nutrients, based only on mineral constituents. Organic constituents, until recently, have been largely ignored. Soil microbes have also been ignored, except for a few high-profile organisms (such as soil-borne pathogens and certain mycorrhizal fungi and N-fixing bacteria).
Predictions of forest growth models have keyed almost exclusively on vegetation, gross land form, and selected site characteristics. The above-ground characteristics of the last rotation were often assumed to be the best indicator for predicting growth, virtually ignoring soil and soil-borne microbiological processes. If soil potential was reduced, the assumption was that fertilizing could offset any damage. This approach has fostered a significantly over-optimistic view of the health and productivity potential for second generation, western forests.
Contemporary studies indicate soil quite literally resembles a living entity, living and breathing through a complex mix of interacting organisms from viruses and bacteria, fungi, nematodes, and arthropods to groundhogs and badgers. Microbial biomass alone could reach 10,000 kg/ha in productive, Inland Western forest soils. In concert, activities of all these organisms are responsible for developing the critical properties that underlie basic soil fertility, health, and productivity. Biologically driven properties resulting from such complex interactions require from a few to several hundreds of years to develop, and no quick fixes are available if extensive damages occur.
In short, soil microbes and the dead woody materials they require are indispensable to and a critical and manipulative component of all natural forest soil ecosystems!
Because microbial processes are fueled by plant debris and other organic matter, they are concentrated in and most characteristic of organic horizons. Because these horizons are shallow they are subject to site disturbance. Thus, they are easily changed or possibly destroyed by disturbance, natural or human-made. This system has evolved to accommodate modest natural disturbances, primarily wildfire and climatic perturbations. However, these ecosystems have not developed under circumstances that exclude fire, or that include soil compaction or extensive physical dislocation of shallow soil horizons. All these can be considered high-risk occurrences, at least over the short run.
Where units have reach-out arms, mechanical harvesting has been purported to cause less disturbance than conventional skidding, because there appears to be potential to stay on specified trails and travel on logging slash. In theory, this should significantly reduce the area and degree of compaction, displacement, and erosion, but the validity of such claims remains largely unsubstantiated. One problem in the Inland Pacific Northwest is insufficient slash to adequately cushion trails." From Natural Resource News Jan 95
Dr. Harvey answered: You don't. Obviously if you have large deposits of decomposed wood deep in soils then you had forests on that site for a very long period of time. In most cases Where you have significant downslope to the forest you do get some movement of soils downslope and they tend to move down and engulf and bury this wood over time. So that's how you get them deep into the soil profile. In addition to just large roots; obviously large roots are well buried in the soil profile as well.
We made a calculation once on some sub alpine fir systems to figure out how many gallons of water per acre there was. As I recall the figure there was some 80 thousand gallons of water per acre stored in wood in late August in that particular site we were looking at. That's quite a lot of water stored in something that when we started out we didn't even expect to find in these forest soils. We expected it to be all either all burned up or decomposed over time. It was something of a revelation to see how persistent this stuff was. Does that answer your question?
Q: So what does the removal of large boles portend for the forests of the future?
A. OK. Obviously we have a situation where if you consider the fact that we might in fairly intensive commercial forestry operations, for example, grow more and more smaller stems to get volumes up. That could, over the long term create, a problem because the kind of wood that's persistent, remember, has to be fairly large. Not only that, probably the most persistent wood is heartwood of the species that I mentioned: Douglas fir, larch, pines. So depending on how you silviculturally approach that system; again if this is an infertile system, and not all are, you could conceivably run yourself into problems by continuously growing more smaller stems to get volumes up. So, yes that could be a problem.
Q: But couldn't it also be a problem if you remove everything that is old and large and dead.
A: Absolutely. We've vociferously recommended against that for a long time now. That's not a good idea.
Background
Sustainable productivity of forests in the northwestern United States is an emerging issue and concern. Processes by which organic and mineral components and their associated nutrients are stored, cycled, and lost from forest ecosystems have been documented by Harvey and others (1980; 1987). Zinke and others (1982) have documented the close association between organic matter and nutrients and the losses of nitrogen, phosphorus, magnesium, and potassium from the forest ecosystem by intensive management. Work in both the United States and Australia (McColl and Powers, 1984; Squires and others, 1985) documents that productivity may be reduced for one or more rotations when significant losses of soil organic matter, nitrogen, and sulfur accompany mechanical site preparation and fuels treatment. Experimental work in Australia suggests that litter and logging residues maintain forest productivity in the second rotation at the first rotation level. This work by Squires and others (7985) shows that residues serve as a mulch to enhance water storage, keep weeds down, and retain nutrients. For whole tree harvest of western hemlock, Sachs and Sollens (1986) found a linear decline of soil organic matter accompanying successive rotations. In another study of whole tree harvest, Kimmins (1977) found that losses of nutrients and organic matter are significant, and that the value of organic matter as a sink for nutrient capital becomes more important as the rates of removal approach the rates of replacement.
Losses of nutrients that accompany timber harvest followed by prescribed fire is a concern and is being monitored in the Pacific Northwest Region (Little and Klock, 1985). Their study shows that care must be used in yarding un-merchantable material (YUM) and in prescribed burning if we are to save nitrogen, sulfur, duff, litter, and woody residues for the next rotations. Boyer and Dell (1980), in a research summary of the effects of fire on soils following timber harvest in the northwestern U.S., show the strong relationship between residual organic matter and the availability of nutrients and moisture. Other research by Amaranthus and Perry (1987; In Press) in southwestern Oregon shows a decline in mycorrhizal activity and seedling survival associated with high losses of organic matter following timber harvest and slash burning. Freedman (1981) has shown that site quality decreases with the combined and interactive effects of fire and harvest.
Organic matter, including large and small woody material, soil organic matter, and forest floor litter has been shown to be the most important factor in maintenance of site quality of western coniferous forest ecosystems (Harvey and others, 1987; Kimmins, 1977). Methods by which it may be measured and managed in forest ecosystems have been identified by Maser and Trappe (1984) and Brown (1985).
Organic matter losses would directly effect soil chemical and physical properties. Losses of organic materials would expose mineral soil to erosion. Runoff would increase where puddled and crusted, bare mineral soil occurs. Available soil water would be reduced as large and small organics are lost by decay and erosion. Soil microflora and microfauna types and species would shift along with changes in soil temperature and in soil chemistry. Nutrient storage and release would decrease as organics are reduced or removed. Similarly, on-site nutrients including, nitrogen, phosphorus, magnesium and potassium would be reduced with loss of organics. Indirectly and in combination these properties would affect productivity of all forest resources. Certainly, the effects would vary with soil types, plant associations and ecosystem processes, but change would occur. Whether the changes would measurably affect productivity in the near-term or long-term depends on inherent site quality. On low site land that has low organic and nutrient reserves, the effect may be observable and measurable within a rotation or less. For high site land that has large organic and nutrient reserves, the effects may be less easily detected or perhaps immeasurable in the near-term. (It is important to point out here the two "functional" pools of organic matter. The soil pool is the critical short-term concern following fire because it stabilizes nutrients and microbes and thereby provides the focus for stand regrowth. The above ground pool represents a longer-term supply of large and small woody material, which has a quite different function in the soil, supplying water storage, sites for nitrogen fixation, and an array of biological functions, most of which are active for many years.) -SITE PRODUCTIVITY Report by E. R. Gross and T. Atzet March 4, 1988 APPENDIX C From FEIS for Silver Fire Recovery Project -- July, 1988
Wood on the forest floor forms long-lasting, moist microsites that may aid forest recovery. Following intense wildfire in southwest Oregon, decaying logs retained 25 times more moisture than surrounding soil (M. P. Amaranthus, D. Parrish and D. A. Perry, manuscript in preparation, Oregon State University, 1988). Such decaying logs may expedite forest recovery by providing important refuge for roots and associated mycorrhizal fungi of pioneering vegetation.
Because most forest stands of the Pacific Northwest appear nitrogen limited, any factor affecting inputs and storage has implications for long-term productivity. Although the amount of nitrogen in sound stemwood may be small compared to that stored on the total site, decaying wood acts as an important locale for asymbiotic nitrogen fixation. Over the long residence time of large wood, inputs and storage of nitrogen are significant for some sites (Larsen et al. 1980, Harvey et al. 1986).
Protecting or enhancing the organic matter in Northwest forest soils is a primary means of maintaining long-term forest growth. Woody debris is a critical component of this organic fraction. The longterm ability of a soil to retain moisture, as well as ectomycorrhizal and nitrogen-fixing organisms, depends upon the continuing input of organic matter. Substantial losses of organic matter, including large wood, from thin, droughty, or infertile soils may result in long-term losses of forest productivity." (from Long-Term Forest Productivity and the Living Soil by M. P. Amaranthus, J. M. Trappe, and R. J. Molina) Emphasis added.
Studies at the Intermountain Forest and Range Experiment Station, Logan, Utah by DeByle and Packer (1981) show that soil erosion from snowmelt overland flow and summer rainstorms from burned and logged plots was substantial for several years following logging. In contrast the test plot showed virtually no erosion.
Soil compaction which results from even a single pass of most wheeled and tracked logging equipment will reduce the site soil productivity. Timothy O. Sexton in his LITERATURE REVIEW AND STUDY PLAN: EFFECTS OF POST-FIRE SALVAGE LOGGING AND GRASS SEEDING ON PINUS PONDEROSA AND PURSHIA TRIDENTATA SURVIVAL AND GROWTH cites research which supports the contention that ground based logging methods contribute to higher levels of soil compaction and disturbance than is commonly assumed in Forest Service analysis.
Topsoil is a reservoir of both nutrients and fungal spores and other propagules important for mycorrhiza formation. Loss of this biological reservoir by erosion will inevitably impair productivity. Reeves et al. (1979) found that the dominant species in a sagebrush (Artemisia) community in Colorado all were mycorrhizal. When topsoil was severely disturbed and eroded, numbers of mycorrhizal propagules were greatly decreased (Moorman and Reeves 1979), and nonmycorrhizal weedy species could successfully reestablish. Little is known about the effects of soil erosion from deforested areas, but the density and diversity of mycorrhizal inocula are reduced." (from Long-Term Forest Productivity and the Living Soil by M. P. Amaranthus, J. M. Trappe, and R. J. Molina) Emphasis added.
This means 24% of the projects on the Wallowa-Whitman are out of compliance with the Forest Plan standard we consider this a significant impact. Other National Forests have similar problems.
| Site Processes | Soil quality monitoring variables |
| Soil erosion | Percentage soil cover or surface disturbance, soil bulk density |
| Nutrient availability | % soil cover, soil color and organic matter content, soil loss |
| Gas exchange | soil bulk density or permeability, water logging etc. |
| Root growth and uptake | Soil structure, strength, water depth |
In addition, the general condition of soils and damage from past and present activities should be discussed by answering the following questions:
There is a broad diversity of organisms involved in these mortality processes. At least 110 species of parasitic wasps and flies attack the budworm and tussock moth. Nearly all occur on the east side and throughout the range of the pests (Carolin and Coulter 1959, Torgersen 1981). Parasitization by this array of species can be substantial. More than half of all tussock moth eggs in a site may be destroyed by a single species of parasitic wasp (Torgersen and Mason 1985). Other studies suggest that parasitization together with other mortality processes can affect the population behavior of the budworm (Torgersen and others 1984). Parasitoids are also dominant factors in the dynamics of tussock moth and larch casebearer populations and contribute to maintaining these insects at nondamaging levels (Mason and others 1983, Ryan and others 1987).
Research on predators and predation processes has contributed to our knowledge of how defoliator populations are regulated. The earliest research on insectivorous birds and ants as predators of tussock moth and budworm was done in eastside ecosystems. Studies in southern Oregon showed that the tussock moth is preyed upon by birds (Torgersen and others 1984). Other eastside studies on the budworm showed that trees where birds and ants are excluded have 10 times as many budworms as trees with the predators (Campbell and others 1983, Campbell 1987). Subsequent observations have documented that there are at least 32 species of birds that feed on the budworm and tussock moth; 20 of these are neotropical migratory species (Sharp 1992). The mountain chickadee and red-breasted nuthatch dominated both observations of actual predation on the budworm and tussock moth and density of individual species (Langelier and Garton 1986, Torgersen and others 1984, 1990). Korol (1985) indicated that 19 species of birds prey on the mountain pine beetle; woodpeckers are the primary avian predators of bark beetle larvae and adults (Dahlsten 1982). Birds also function in spreading diseases of insects, dispersing seeds of some forest trees and shrubs, and contributing to nutrient cycling by spreading wood-rotting fungi (Otvos 1979).
Arthropod predators of defoliators and bark beetles include spiders, ants, true bugs, nerve-winged insects, beetles, flies, and wasps. Over a dozen species of forest-dwelling ants prey on budworm and tussock moth (Bain 1974; Markin 1975, 1979; Torgersen and others 1990; Youngs and Campbell 1984). Among these, carpenter ants and thatch mound-building ants live underground or in association with stumps, logs, and snags, but ants forage in the crowns of living trees where they tend aphids or hunt for prey on the foliage. In one study, 85 percent of the budworm pupae artificially stocked on experimental branches were killed by ants within 3 days of stocking (Campbell and Torgersen 1982). Ants significantly reduce budworm populations on conifer seedlings in sites regenerated by seed-tree cuts (Campbell and others 1984). Ants are also a primary dietary component for pileated woodpecker (Beckwith and Bull 1985), a bird designated as a Management Indicator Species by the USDA Forest Service (Arwin 1987). Thus, management actions that favor populations of forest-dwelling ants are important both for regulation of pest insects and for providing a prey base for an Indicator Species.
Predation of defoliating insects by spiders is less well known than that of birds and ants but it is recognized as an important predatory component in forest ecosystems. This group comprises a major portion of the foliage dwelling arthropod fauna in mixed-conifer forests in the montane West (Mason 1992, Moldenke and others 1987). Documentation of spider predation and its effects on population dynamics of tussock moth and budworm has been reported by Torgersen and Dahlsten (1978), Mason and Torgersen (1983), Fellin (1985) and Mason and Paul (1988). Nothing is known of potential effects of silvicultural practices on spiders.
Mortality processes are interrelated in various ways, but one of the structural features they have in common is dead wood-both standing snags and downed, woody material. Therefore, restoration activities should include dead wood components. Data are now being analyzed that will clarify the question of how much dead wood, in what size classes, and of what species and decay classes is appropriate in the ecological management of eastside mixed-conifer stands (Torgersen and Bull, in preparation)....
To prevent possible further destabilization of eastside forest ecosystems, given our current limited knowledge of ecosystem function, we should maintain old, relict stands. Precisely because these stands have survived a long time suggests that they may contain key elements necessary for the pursuit of sustainable ecosystem management. Loss of old-growth will result in loss or depletion of species that are narrowly adapted to such stands and the standing and downed, dead wood components associated with them (Thomas and others 1975). As Leopold (1953) cautioned, "To keep every cog and wheel is the first precaution of intelligent tinkering."
Salvage of insect-killed trees is currently being used to prevent further buildup of woody fuels, to capture merchantable volume before it deteriorates, and to improve conditions for stand replacement by shade intolerant early successional species. In sales involving removal of standing, insect-killed trees, current Forest Service standards and guidelines for residual dead woody debris are being used. Recent research may yield information useful for updating standards and guidelines governing amounts of woody debris to be left as substrate for predators and other dead-wood-dependent species (Bull and Holthausen 1993, Maser and Trappe 1984, Torgersen and Bull, in preparation)." (By Torolf R. Torgersen from Eastside Forest Ecosystem Health Assessment Richard L. Everett, Assessment Team Leader Published by: U.S. Department of Agriculture, Forest Service Pacific Northwest Research Station General Technical Report PNW-GTR-330 April 1994)
Please analyze and cite the latest recommendations
of researchers regarding snag and down log numbers in relation to management
indicator species (MIS). Some of these MIS (specifically cavity excavators
and cavity nesters) play a significant role in keeping insect infestations
at endemic levels and any restoration plan must include a plan for restoring
these species to pre-settlement population levels. We also request a restoration
plan for any insect predators of the insect pests in question. We request
that large leave tree and large snags be protected across the landscape.
We would like to see snags and replacement trees protected from windthrow
and other edge effects.