SOIL MANAGEMENT AS AN INTEGRAL PART OF SILVICULTURAL SYSTEMS

Russell T. Graham
Don Minore
Alan E. Harvey
Martin F. Jurgensen
Deborah S. Page-Dumroese

ABSTRACT

Forest management is at a critical juncture. Concepts and strategies for managing forests to produce goods and services, yet maintain functioning visually pleasing forests, are being debated, developed, and implemented. A well-designed and implemented silvicultural system is basic to good forest management. Means of protecting soil and all factors affecting soil properties must be integrated into silvicultural systems. Inappropriate silvicultural techniques can degrade forest productivity especially by compacting, displacing, or destroying soil surface layers rich in organic matter. Because both short- and long-term productivity can be influenced by changes in these layers, we make several recommendations on how to protect soil when developing prescriptions for any silvicultural system.

INTRODUCTION

Forest management is at a critical juncture. Not since the late 1960's and early 1970's has the management of forests been more scrutinized. The management controversies of the Bitterroot and Monongahela National Forests contributed to passing of the National Forest Management Act of 1976. In response to the Act, forest practices were modified, but the primary focus of forest management continued to be on the production of timber-based commodities. Silvicultural systems were designed to efficiently produce lumber and fiber-based products from a variety of lands. Much of society was content with this form of management until more and more virgin forests were converted to young, fast-growing, high-yield, commodity-producing tree farms.

The demands of society are changing as the 21st century approaches. No longer is commodity production the only desirable forest attribute. Diversity, sustainability, old-growth, scenic values, wildlife (both game and non game), and water quality are becoming increasingly important. To provide and maintain these attributes requires some basic changes in forest management; new initiatives and concepts are now being developed.

"New Forestry" is one of these. It is a concept defined as "the management of ecosystems and not just the regeneration of trees" (Franklin 1989). In addition, a broad philosophy of forest management by the Forest Service, U.S. Department of Agriculture, entitled "New Perspectives," is also in the process of being defined and implemented. Both of these strive to make forest management more broadly based ecologically and responsive to society's demands.

New perspectives and new forestry both use the ecosystem as the basic unit of land management. The management of forest ecosystems to meet objectives is the practice of silviculture (Smith 1962). The silvicultural methods and manipulation techniques available to manage forests need to be assembled into complete silvicultural systems, planned programs of treatments to be applied throughout the life of the forest. This will be more important than ever, if new forestry and new perspectives are going to succeed and if ecologically sound silvicultural systems are to be implemented. Soil is often not fully integrated into our silvicultural systems, yet as outlined here, it is critical to the regeneration, productivity, nutrient value, and moisture-retention abilities of all forested sites. After discussing the role of surface soil layers in the forest, we outline silvicultural methods and their effects on soils, and recommend soil protection guidelines for silvicultural prescriptions.

FOREST SOILS

Litter, humus, soil wood, and certain key properties of the surface mineral layers of forest soils are usually most critical when developing silvicultural systems. These are the soil layers most easily and commonly disturbed by silvicultural activities, yet they are crucial to forest productivity.

Woody Residues

Although they are not a soil component, the quantity, quality, and disposition of woody residues can also influence forest soils greatly. The quantity of downed material can vary dramatically, depending on site, forest conditions, and forest treatments (table 1).

**TABLE 1**
Average downed woody loadings, duff depths, and percentages rotten from the Forest Inventory by cover type for east and westside National Forests of the Northern Rocky Mountains (Brown and See 1981)
Cover type¹	Westside forests			Eastside forests
Cover type¹	Total (Tons/acre)	Duff depth (Inches)	Rotten large (Percent)	Total (Tons/acre)	Duff depth (Inches)	Rotten large (Percent)
¹PP = Ponderosa pine, Pinus ponderosa DF = Douglas-fir, Pseudotsuga menziesii LP = Lodgepole pine, Pinus contorta L = Larch-grand fir, Larix occidentalis-Abies grandis S-F = Spruce-subalpine fir, Picea engelmannii-Abies lasiocarpa C-H = Cedar-hemlock, Thuja plicata-Tsuga heterophylla.
PP	12.9	0.6	61	5.0	0.6	70
DF	15.7	.9	63	12.0	1.0	63
LP	17.5	1.1	59	16.1	1.1	55
L	21.4	1.2	58	—	—	—
S-F	26.7	1.4	52	22.7	1.3	52
C-H	33.4	1.4	57	—	—	—

Physically, woody residues protect soil from erosion, displacement, and compaction. In addition, they can protect regenerating forests from both abiotic and biotic elements (Edgren and Stein 1974). Residues provide shade and protection from wind and snow, and can be critical factors in protecting newly established seedlings from livestock (Graham and others, in press). Regeneration can be damaged by falling or rolling logs, and fuel loadings can threaten forests by becoming a fire hazard. As logs and other woody debris decay they can become incorporated into the litter, humus, and mineral soil horizons.

Chemically, woody residues are an important forest component. Decaying logs, especially those with the incipient and advanced forms of decay, are excellent substrata for nonsymbiotic nitrogen (N) fixation (table 2). If sites do not have nitrogen-fixing plants present, such as ceanothus (Ceanothus spp.), shepherdia (Shepherdia canadensis), or leguminous forbs, these nonsymbiotic forms of nitrogen fixation are crucial. Also, woody residues release nutrients during decay that are critical for forest growth (Harvey and others 1987). Therefore, the quantity and kind of forest residues on a site can be critically important for maintaining site productivity.

**TABLE 2**
Woody residue weights¹ and associated N additions² from nonsymbiotic N fixation on four old-growth forest sites in western Montana and northern Idaho (Jurgensen and others 1987)
Decay class	Douglass-fir (Montana) (Tons/acre)	Douglass-fir (Montana) (Lb/acre)	Cedar-hemlock (Montana) (Tons/acre)	Cedar-hemlock (Montana) (Lb/acre)	Subalpine fir (Montana) (Tons/acre)	Subalpine fir (Montana) (Lb/acre)	Cedar-hemlock (Idaho) (Tons/acre)	Cedar-hemlock (Idaho) (Lb/acre)
¹Dry weights of woody residues >3 inches in diameter. ²Total N fixed over a 180-day period.
Incipient	5.0	0.03	10.7	0.07	27.4	0.17	3.1	0.04
Intermediate	7.1	.12	15.5	.18	15.7	.26	21.3	.40
Advanced	8.0	.20	10.9	.25	21.8	0.70	44.4	2.71
Total	20.1	.35	37.1	.51	65.0	1.14	68.8	3.15

Litter

The surfaces of forest soils are usually covered with a layer of litter. This material is composed of organic matter (OM) from trees, shrubs, grasses, forbs, other plant material, and animal material from the site. This layer is unconsolidated and undecomposed. It can vary widely depending on site, decomposition rates, and vegetation (table 3).

**TABLE 3**
Depth and distribution of soil organic materials among major soil components (Harvey and others 1989)
Site description	Organic matter depth¹ (cm)	Percent distribution in Litter	Percent distribution in Humus	Percent distribution in Decayed Wood
¹Thickness of organic matter layers in the surface 30 cm of soil. ²Major conifer species occupying the site, WWP = western white pine (Pinus monticola), LPP = lodgepole pine (Pinus contorta), WL = western larch (Larix occidentalis).
Undisturbed stands:
Hemlock-climax (MT)	3.8	12	38	51
Subalpine fir (MT)	3.5	7	45	48
Douglas-fir (MT)	2.3	6	58	35
Ponderosa pine (WA)	2.0	30	19	51
Grand fir (ID)	1.7	31	68	2
Hemlock (ID) 200-yr WWP²	1.5	25	61	14
Disturbed stands:
Subalpine fir (MT) 50-yr LPP²	1.9	19	58	23
Subalpine fir (MT) 15-yr WL²	1.5	21	41	39
Douglas-fir (MT) 15-yr LPP²	.5	46	40	14

Litter layers protect the surface of the soil by acting as a mulch on the soil surface to retain moisture in the lower layers. Soils protected by litter are less prone to erosion (Rothacher and Lopushinsky 1974). Likewise, litter layers protect soils from compaction (Lull 1959). Litter is not usually an important site for ectomycorrhizal activity, but if moisture is maintained in these layers ectomycorrhizae are present (Harvey and others 1987).

Litter can be an impediment to both natural and artificial regeneration of trees. If the litter layer is thick, which often occurs in ponderosa pine (Pinus ponderosa) forests where decomposition is slow, tree seeds falling on this layer germinate, but because litter dries rapidly they may die (Pearson 1949). On the other hand, if litter remains moist during germination and early seedling growth (a situation that can be found in many hemlock [Tsuga] and cedar [Thuja] sites) successful establishment of tree seedlings is quite common (Minore 1972). Often the forest being generated on these organic seed beds does not produce the desired mix of species or stand structure to meet some forest management objectives.

Humus

Humus is made up of highly decomposed organic material with no recognizable plant parts. Humus layers are usually relatively shallow, depending on the site, decomposition rates, and vegetation (table 2). Humus is a dynamic part of the soil horizon. It is a major substrate for both high nitrogen fixation and nitrogen storage, and it is rich in other essential elements (calcium, potassium, magnesium) (Harvey and others 1987). Humus contains many roots and maintains soil moisture, making it important for ectomycorrhizal activity. This layer often represents the transition between organic layers and the mineral soil. Very often this layer when burned over can provide numerous microsites for natural regeneration (Haig and others 1941).

Soil Wood

Soil wood as a component of forest soils is often overlooked. Soil wood is highly decomposed wood, incorporated into soil horizons usually in the form of brown cubicle rot. It can also occur in a fine powdery form, usually much older. As with the other organic components, quantity and type can be quite variable (table 2). Soil wood is a dynamic part of the soil system. Soil wood is not a continuous layer, but occurs in deep pockets created by buried logs and decaying stumps (Reinhardt and others, in press). Soil wood should not be confused with rotten wood or residue that is on the surface of the soil.

Soil wood protects soils from compaction and provides OM to the mineral soil. It is also an important source of N fixation and N storage (Harvey and others 1989). Soil wood is an excellent substrate for ectomycorrhizae. In addition, because of its water retention ability and physical characteristics, soil wood often contains root systems of conifers that grow rapidly and concentrate in these buried logs and stumps.

Surface Mineral Soil

The surface 5 to 10 cm of mineral soil is derived from the parent materials of the site, but is also highly influenced by vegetation and surface organic layers. The OM incorporated into shallow mineral horizons carries important properties into the mineral soil base. Mineral soil with good OM levels has better nutrition, water-holding capacity, and structure than soils with small amounts of OM. In addition, OM-rich mineral soils are excellent sites for nitrogen fixation and ectomycorrhizae (Harvey and others 1987). Surface layers are highly susceptible to compaction and displacement. Mineral soils with high volcanic ash content are particularly sensitive to forest operations. (See Hironaka and others, Page-Dumroese and others, these proceedings).

THE SILVICULTURAL SYSTEM

A silvicultural system is a planned program of treatments applied throughout the life of a stand (Smith 1962). The silvicultural system should integrate all planned site treatments and methods that will be used to implement the system (Graham 1990). Numerous factors should be considered during its development. Foremost among these are the site and stand conditions that determine the timing of treatments and what treatments are required to meet management objectives.

Regeneration Methods

The choice of regeneration method is, in many ways, the most critical decision regarding the entire system. It should be selected carefully and consider all abiotic and biotic elements that might influence forest regeneration and development, but soil properties are especially important. Physical properties of the mineral soil, especially water-holding capacity, can be used to help determine which regeneration method would be the most appropriate (fig. 1). For example, stands located on soils with high amounts of available water would be most suited to the clearcut method and stands on droughty soils with little available water would be more appropriate for selection or heavy shelterwood methods.

Figure 1—Regeneration methods in relation to soil moisture and texture. [view larger image - 56K] [Text description of this figure]

To implement the regeneration method, timber harvesting and harvesting machinery are usually used. Forest managers, for the most part, understand the importance of protecting forest soils from erosion and compaction through the application of careful harvesting techniques dependent on soil type and slope of the harvest unit. Even with this awareness, however, the importance of minimizing total soil disturbance is not always recognized.

In general, cable yarding systems compact and displace less soil than tractor yarding systems. Also, by using cable yarding over snowpacks during the winter, for example, on extremely shallow and sensitive soils, even less soil disturbance occurs (fig. 2). Ground-lead yarding in the summer can cause considerable soil disturbance. This can be very destructive to the critical surface layers of organic matter and shallow mineral soil.

Figure 2—Soil disturbance by depth class (light 0-2 inches, deep 2-10 inches, very deep >10 inches) for ground (GRND) yarding during the summer (SUM), ground yarding during the winter (WIN), cable (CAB) yarding during the summer, and cable yarding during the winter for harvesting operations in British Columbia (Krag and others 1986). [view larger image - 64K] [Text description of this figure]

Tractor yarding not only disturbs more soil than cable yarding, it also can compact soil. Compaction occurs not only in the surface layers, but at greater soil depths (Froelich and others 1985). Soil compaction in deep soil layers can be greater and more long-lasting than at the surface because of deep-layer isolation from organic matter and surface litter. Because yarding techniques can displace and compact forest soils, techniques specified in the silvicultural system need to be appropriate for the soils on which they are to be used. Care should always be taken to minimize soil displacement and compaction during any harvesting operation.

As harvesting equipment and processing plants become more efficient, and wood utilization becomes more intensive, greater amounts of fiber are removed from the forest. By removing this material less organic material may be available for incorporation into the soil. Therefore, it will become more critical that sufficient organic material remains after intensive harvesting to provide organic parent material to maintain both short- and long-term productivity.

Postharvest Treatments

After the choice of regeneration and harvest methods, fire hazard reduction and site preparation become the most important elements of the silvicultural system. Both natural and artificial regeneration require creating the proper conditions for establishment and growth, usually a compromise. Objectives of site preparation include: exposing mineral soil, creating access for planters, reducing competing vegetation, reducing the incidence of disease, reducing wildfire hazard, minimizing seedling damage, and encouraging early growth. Often when meeting these objectives the factors critical for tree growth (moisture, temperature, light, and nutrition) are not optimized (Graham and others 1989a).

Specific soil characteristics need to be included in system planning. How much or how little soil disturbance is necessary to establish and grow specific forest vegetation? Depending on the forest floor depth and condition of residue, litter, humus, and soil wood, highly variable disturbances may be required for artificial regeneration. Trees can be planted successfully near and through surface organic materials as long as good root-to-soil contact is made and the medium is moist. Likewise, depending on the desired vegetation, very little disturbance may be needed for natural conifer regeneration.

There are three methods of preparing sites for regeneration: mechanical, chemical, and fire. Chemical methods of site preparation are infrequently used in the Inland and Pacific Northwest. When they are used, a good understanding of how they interact with the soil is extremely important. Depending on site and soil characteristics, chemicals can be volatilized, absorbed, leached, or degraded. Therefore, chemical site preparation should be carefully applied and fully integrated into the silvicultural system when it is used (Baumgartner and others 1986).

Tractor piling of logging debris and machine site preparation is used widely throughout the West. Similar to tractor yarding, tractor piling can both compact and disturb soil surface layers (Minore and Weatherly 1988, 1990). The more the disturbance, the greater the loss of surface organic layers. Because tractor piling does impact the soil layers through displacement and compaction, tractor piling of logging debris can adversely affect tree growth (Bosworth 1989). For example, of several young stands measured in western Oregon the majority were growing below their potential after the sites were tractor piled (fig. 3). Likewise, when organic horizons are maintained or enhanced, seedling growth can be improved and long-term site productivity increased (Graham and others 1989b, in press).

Figure 3—A comparison of measured Douglas-fir seedling heights on plantations where slash was broadcast burned. Points below the diagonal line indicate measured heights shorter than predicted heights at age 5. Points above the line indicate measured heights taller than predicted heights (Minore 1986). [view larger image - 16K] [Text description of this figure]

Broadcast burning, if properly applied, can be highly effective and beneficial to the site (Graham and others 1989a). If burning conditions are optimum when the humus and soil wood are moist and fires do not destroy these materials, nutrients, especially N, can condense in underlying mineral layers when released from the burning litter and other surface materials (Harvey and others 1989). Broadcast burning, if properly applied, can allow stands to grow closer to their potential than tractor-piled stands (fig. 4).

Figure 4—A comparison of measured Douglas-fir seedling heights on plantations where slash was piled and burned. Points below the diagonal line indicate measured heights shorter than predicted heights at age 5. Points above the line indicate measured heights taller than predicted heights (Minore 1986). [view larger image - 20K] [Text description of this figure]

After the site preparation and hazard reduction treatments are completed it is imperative to leave sufficient large woody material on the site. As mentioned earlier, residue has several properties important for maintaining forest productivity. We recommend leaving a minimum 10 to 15 tons per acre of large woody material (>3 inches in diameter) after timber harvesting and other site treatments (Harvey and others 1987). We are presently refining these recommendations to make them more site specific based on habitat type.

Intermediate Stand Treatments

Cleanings, weedings, and thinnings are common intermediate stand treatments used in silvicultural systems. If these operations are mechanized, there is potential to compact and displace soil. Consequently, the same concerns described for harvesting and site preparation treatments, in relation to soil properties, should be evaluated when applying intermediate treatments. Another concern with intermediate treatments is the removal of material that normally would be added to the organic component of soil. Removal of wood material during intermediate treatments and final harvest should be limited and always allow for sufficient woody debris to remain on site to comply with the recommended amount needed to maintain long-term productivity.

RECOMMENDATIONS

We have several specific recommendations on how to protect and manage soil when developing prescriptions for any silvicultural system.

Consider soil properties such as texture, nutrition, depth, structure, and organic matter content, in all phases of silvicultural system development.
Be vigilant in protecting the surface OM and mineral layers.
1. Use cable systems for yarding when possible and time these operations to minimize soil disturbance.
2. Design tractor yarding systems to minimize number of trails and disturbance and do not operate under high moisture conditions.
3. Use tractor piling of logging debris judiciously. Grapple piling of debris is preferred.
4. Use prescribed fire when possible for fuel reduction and site preparation where necessary. Maintain high moisture content in humus and soil wood when burning.
Prescribe site preparation to meet specific biological objectives for the development of forests and not to meet administrative objectives.
Make sure that minimum woody residues are maintained on site (10 to 15 tons/acre until more site-specific recommendations can be developed). This is critical as wood utilization intensity is increased.
Minimize the destruction of either incipient or advance decay forms of residues.
Do not allow excess fuel accumulations, but protect ecosystems from late-summer wildfires.

CONCLUSIONS

Soil is literally the foundation of ecosystems. It must be protected if forests are going to be sustained and is even more critical when the threats of global climate change and increased acid deposition are contemplated. As soil is the foundation of the ecosystem, the silvicultural system is the foundation of forest management. Therefore, means of protecting soil and all of its properties must be integrated into the silvicultural system if the concepts of new forestry and new perspectives are going to succeed.

REFERENCES

Baumgartner, D. M.; Boyd, R. J.; Breuer, D. W.; Miller, D. L. 1986. Weed control for forest productivity in the Interior West. Pullman, WA: Washington State University, Cooperative Extension: 148 p.

Bosworth, B. 1989. Height growth on burned, piled and nonprepped clearcuts, 17 to 22 years after harvest. In: Baumgartner, D. M.; [and others], eds. Prescribed fire in the intermountain region: forest site preparation and range improvement; symposium proceedings. Pullman, WA: Washington State University, Cooperative Extension: 65-67.

Brown, J. K.; See, T. E. 1981. Downed woody fuel and biomass in the northern Rocky Mountains. Gen. Tech. Rep. INT-117. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 48 p.

Edgren, J. W.; Stein, W. I. 1974. Artificial regeneration. In: Cramer, O. P., ed. Environmental effects of forest residues management in the Pacific Northwest: a state-of-knowledge compendium. Gen. Tech. Rep. PNW-24. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station: M1-M32.

Franklin, J. 1989. Toward a new forestry. American Forests. 95: 37-44.

Froehlich, H. A.; Miles, D. W. R.; Robbins, R. W. 1985. Soil bulk density recovery on compacted skid trails in central Idaho. Soil Science Society of America Journal. 49: 1015-1017.

Graham, R. T. 1990. Importance of integrating harvesting, site preparation, and regeneration: the silvicultural system. In: Forestry on the frontier; Proceedings, Society of American Foresters annual meeting; 1989 September 24-27; Spokane, WA. Washington, DC: Society of American Foresters: 217-218.

Graham, R. T.; Harvey, A. E.; Jurgensen, M. F. 1989a. Site preparation strategies for artificial regeneration: Can prescribed burning fill the bill? In: Baumgartner, D., ed. Prescribed fire in the intermountain region: forest site preparation and range improvement. Pullman, WA: Washington State University, Cooperative Extension: 83-89.

Graham, R. T.; Harvey, A. E.; Jurgensen, M. F. 1989b. Effect of site preparation on survival and growth of Douglas-fir (Pseudotsuga menziesii Mirb. Franco.) seedlings. New Forests. 3: 89-98.

Graham, R. T.; Harvey, A. E.; Page-Dumroese, D. S.; Jurgensen, M. F. [In press]. Importance of soil organic matter in the development of interior Douglas-fir. In: Baumgartner, D. M.; Lotan, J., eds. Interior Douglas-fir: the species and its management. Pullman, WA: Washington State University.

Graham, R. T.; Kingery, J.; Volland, L. [In press]. Livestock and forest management interactions. In: Black, H., ed. A silvicultural approach to animal damage management in Pacific Northwest forests. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station.

Haig, I. T.; Davis, K. P.; Weidman, R. H. 1941. Natural regeneration in the western white pine type. Tech. Bull. 767. Washington, DC: U.S. Department of Agriculture. 99 p.

Harvey, A. E.; Jurgensen, M. F.; Graham, R. T. 1989. Fire-soil interactions governing site productivity in the Northern Rocky Mountains. In: Baumgartner, D. M.; [and others], eds. Prescribed fire in the intermountain region: forest site preparation and range improvement. Pullman, WA: Washington State University, Cooperative Extension: 9-18.

Harvey, Alan E.; Jurgensen, Martin F.; Larsen, Michael J.; Graham, Russell T. 1987. Decaying organic materials and soil quality in the Inland Northwest: a management opportunity. Gen. Tech. Rep. INT-225. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 15 p.

Jurgensen, M. F.; Larsen, M. J.; Graham, R. T.; Harvey, A. E. 1987. Nitrogen fixation in woody residue of northern Rocky Mountain conifer forests. Canadian Journal of Forest Research. 17: 1283-1288.

Krag, R.; Higginbotham, K.; Rothwell, R. 1986. Logging and soil disturbance in southeast British Columbia. Canadian Journal of Forest Research. 16: 1345-1354.

Lull, H. W. 1959. Soil compaction on forest and rangelands. Misc. Publ. 768. Washington, DC: U.S. Department of Agriculture. 33 p.

Minore, D. 1972. Germination and early growth of coastal tree species on organic seedbeds. Res. Pap. PNW-135. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 18 p.

Minore, D.; Weatherly, H. G. 1988. Yarding-method and slash-treatment effects on compaction, humus, and variation in plantation soils. Res. Note PNW-476. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 6 p.

Minore, D.; Weatherly, H. G. 1990. Effects of site preparation on Douglas-fir seedling growth and survival. Western Journal of Applied Forestry. 5: 49-51.

Pearson, G. A. 1949. Management of ponderosa pine in the Southwest. Agric. Monogr. 6. Washington, DC: U.S. Department of Agriculture, Forest Service. 218 p.

Reinhardt, E. D.; Brown, J. K.; Fischer, W. C.; Graham, R. T. [In press]. Prescribed fire in Northern Rocky Mountain logging slash. Res. Pap. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station.

Rothacher, J.; Lopushinsky, W. 1974. Soil stability and water yield and quality. In: Cramer, O. P., ed. Environmental effects of forest residues management in the Pacific Northwest: a state-of-knowledge compendium. Gen. Tech. Rep. PNW-24. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station: D1-D23.

Smith, D. M. 1962. The practice of silviculture. New York: John Wiley. 578 p.

Paper presented at the Symposium on Management and Productivity of Western-Montane Forest Soils, Boise, ID, April 10-12, 1990.

Russell T. Graham, Alan E. Harvey, and Deborah S. Page-Dumroese are Research Forester, Project Leader, and Research Soil Scientist, respectively, with the Intermountain Research Station, Forest Service, U.S. Department of Agriculture, Moscow, ID 83843. Don Minore is a Plant Ecologist with the Pacific Northwest Research Station, Forest Service, U.S. Department of Agriculture, 3200 Jefferson Way, Corvallis, OR 97331. Martin F. Jurgensen is Professor of Forest Soils, School of Forestry and Wood Products, Michigan Technological University, Houghton, MI 49931.

A Guide to Soil Quality Monitoring for Long Term Ecosystem Sustainability on Northern Region National Forests