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AFFECTED ENVIRONMENT & ENVIRONMENTAL CONSEQUENCES CHAPTER 3 low bulk densities and low compaction potential. Mechanical disturbances can still reduce soil porosity to levels that limit vegetative growth, especially where there is a lack of woody debris and surface organic matter to help cushion the weight distribution of ground-based equipment. The sandy-textured surface layers are also easily displaced by equipment operations, especially during dry moisture conditions. Soil displacement damage resulting from the maneuvering of equipment is most likely to occur on the steeper landforms. Natural rates of surface erosion on undisturbed sites with gentle slopes are low because soils are protected by vegetation and organic litter layers. Accelerated rates of surface erosion are usually associated with disturbances or events that reduce vegetative cover, displace surface organic layers, or reduce soil porosity through compaction. Currently, soils in the planning area are adequately protected to maintain erosion rates within acceptable limits. Erosion associated with water is generally not a concern due to gentle slopes and low-to-moderate erosion hazard ratings associated with the dominant landtypes in the planning area. The low amounts of overland flow are associated the high infiltration and percolation rates typical of the sandy textures of the ash-influenced soils in the planning area. When water is channeled, particularly on disturbed sites such as road surfaces, trails, skid trails, and log landings, these soils are easily eroded (Soils Report pages 6-7). The absence of rock fragments on the surface and within soil profiles makes these soils well suited for subsoiling treatments. These treatments loosen compacted soil layers and improve the ability of the soil to supply nutrients, moisture, and air that support vegetative growth and biotic habitat for soil organisms (Soils Report page 6). Existing Condition of the Soil Resource Natural disturbances are not included as existing sources of detrimental soil conditions. Enough time has passed since the occurrence of past wildfires that there is currently no evidence of severely burned soils and/or accelerated surface erosion within affected areas. There are no known natural or management related landslides identified or known to exist within the planning area. The coarse textured soils common to the area are highly permeable and preclude the buildup of hydraulic pressures that could trigger landslides. There are no seeps or springs on steep slopes. Landform types in the planning area do not meet the criteria for landslide prone terrain (Soils Report, pages 8-9). Soil compaction and displacement associated with logging facilities – skid trails, log landings, and temporary roads – account for the majority of detrimental soil conditions associated with ground based logging operations. Local knowledge and experience with past and current harvest practices, research references, local monitoring reports, and field investigations were used to estimate existing soil conditions within each of the activity areas planned for this project (Soils Report page 10). Firewood cutting, both legal and illegal, is relatively minor within the planning area, in large part due to the low quality of the wood when compared with other areas on the district. The amount of detrimentally impacted soils associated with this activity is likely accounted for in the acreage associated with logging facilities (landings and skid trails), dispersed recreation sites, and non-designated roads and trails. The extent of detrimental soil conditions associated with recreation use, livestock grazing, and special use facilities is relatively minor in comparison to the transportation system and past logging disturbances. It is expected that adequate amounts of coarse woody material and surface organic matter currently exist to protect mineral soil from erosion and provide nutrients for maintaining soil productivity over much of the project area. 3-92
AFFECTED ENVIRONMENT & ENVIRONMENTAL CONSEQUENCES CHAPTER 3 A more complete discussion regarding the levels of detrimentally impacted soils associated with management activities can be found in following subsections (<strong>Environmental</strong> Effects, Alternative 1 and Coarse Woody Material and Surface Organic Matter) and in the Soils report on pages 9 through 13. Management Direction The Pacific Northwest Region developed soil quality standards and guidelines (FSM 2520, R6 Supplement No. 2500-98-1) that limit detrimental soil disturbances associated with management activities. This supplement requires that when initiating new projects; 1. new activities do not exceed detrimental soil conditions on more than 20 percent of an activity area including the permanent transportation system; 2. in activity areas where less than 20 percent detrimental soil impacts exist from prior activities, the cumulative amount of detrimentally disturbed soil must not exceed the 20 percent limit following project implementation and restoration; and 3. in activity areas where more than 20 percent detrimental soil conditions exist from prior activities, the cumulative detrimental effects from project implementation and restoration must, at a minimum, not exceed the conditions prior to the planned activity and should move conditions toward a net improvement in soil quality. This guidance supplements LRMP standards and guidelines that are designed to protect or maintain soil productivity (Soils Report pages 14-15). Detrimental soil impacts are those that meet the following criteria: Detrimental Compaction - in volcanic ash / pumice soils is an increase in soil bulk density of 20 percent, or more, over the undisturbed level; Detrimental Puddling - occurs when the depth of ruts or imprints is six inches or more; Detrimental Displacement - the removal of more than 50 percent of the A horizon from an area greater than 100 square feet, which is at least 5 feet in width; Severely Burned - when the mineral soil surface has been significantly changed in color, oxidized to a reddish color, and the next one-half inch blackened from organic matter charring by heat conducted through the top layer on an area 100 square feet or greater with a width of at least five (5) feet (Soils Report page 14). Soils in the planning area are not susceptible to puddling damage due to their lack of plasticity and cohesion (Soils Report page 6). There is no evidence of severely burned soils from past wildfires (Soils Report page 8) or from past timber management and fuel reduction activities off of designated logging facilities (Soils Report page 11). Soil Productivity Issues Issues are used to formulate alternatives, prescribe mitigation measures, and analyze the environmental effects of management activities. Key issues were originally identified by the Interdisciplinary Team (IDT) and emphasized by the public during scoping. Soil productivity was not identified as a key issue and was not used to formulate either of the action alternatives. It is utilized to help the decision maker, the Forest Supervisor, to determine which alternative will be selected for implementation. Plans for projects must include provisions for mitigation of ground disturbances where activities are expected to cause resource damage that exceeds Regional and LRMP standards and guidelines. The soil productivity issue for the Opine planning area is: The proposed use of ground-based equipment can potentially increase the amount and distribution of detrimental soil conditions within the individual activity areas proposed for mechanical treatments. The removal of trees from activity areas can potentially cause adverse changes in organic matter levels. 3-93
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United States Department of Agricul
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Abstract: The Opine Planning Area i
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PROJECT LOCATION CHAPTER 1 Figure 1
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PURPOSE AND NEED CHAPTER 1 commerci
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PLANNING DIRECTION - MANAGEMENT ALL
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PLANNING DIRECTION - MANAGEMENT ALL
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OTHER PLANNING DIRECTION & STRATEGI
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OTHER PLANNING DIRECTION & STRATEGI
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ANALYSIS ISSUES CHAPTER 1 The Opine
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ANALYSIS ISSUES CHAPTER 1 Soils The
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ALTERNATIVE DESCRIPTIONS CHAPTER 2
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COMPARISON OF ALTERNATIVES CHAPTER
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COMPARISON OF ALTERNATIVES CHAPTER
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IMPLEMENTATION GUIDELINES CHAPTER 2
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AFFECTED ENVIRONMENT & ENVIRONMENTA
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Environmental Assessment

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