Clear Lake Sage-Grouse Habitat Improvement Project Phase IV Soils Report

Transcription

1 Clear Lake Sage-Grouse Habitat Improvement Project Phase IV Soils Report January 11, 2016 By Sue Goheen, Forest Soil Scientist Introduction This report focuses on the effects of the proposed action on soil productivity within the Clear Lake Sage-Grouse Habitat Improvement Project Phase IV project area. The report includes existing condition, affected environment, environmental consequences, and direct and indirect effects. Soil is the basic resource of the forest and rangeland, and is key to the productivity of an area. Soil directly or indirectly supports all other resources. It serves as a growth medium for plants, filters biological and chemical substances and regulates water transmission. A major goal for soil resource management is long-term maintenance of soil productivity and watershed protection. This requires avoiding management actions that would irreversibly impair soil productivity. It is necessary to monitor soil productivity to detect significant changes caused by management actions. Maintaining soil productivity also requires restoring or improving soils in areas where they have been degraded. Controlling soil erosion, compaction, and maintaining the nutrient balance during range management, timber harvest, vegetative manipulation, and postfire rehabilitation is vital to long-term soil productivity and protection of down-stream water quality. To reduce loss of soil structure and nutrients, practices would include maintaining ground cover to reduce soil loss and limiting livestock and equipment use on soils during wet weather (Modoc National Forest Land and Resource Management Plan, 1991). 1 The Modoc National Forest Land and Resource Management Plan (LRMP) requires that project plans for activities implement appropriate Best Management Practices (BMP) and other projectspecific mitigation measures for soil and water protection. This includes areas of concentrated use. The Modoc National Forest uses the allowable 15% detrimental disturbance as a measure to track the impact of disturbance on site productivity. As a minimum, 85% of areas affected by soil-disturbing activities will not exceed soil property thresholds in the Soils Guidelines A-G in the LRMP, 1991 (4-21, 22). This includes maintaining mineral organic matter in 85% of its natural condition in the upper 12 inches of the soil profile, porosity at least 90% of its natural condition, a minimum of 30% of the soil surface covered with intact duff, five large logs per acre, and remaining within the allowable soil loss. Soil quality analysis standards provide threshold values that indicate when changes in soil properties and soil conditions would result in significant change or impairment of the productivity potential, hydrologic function, or buffering capacity of the soil. Detrimental soil disturbance is the resulting condition when threshold values are exceeded.

2 Project Location The Clear Lake Sage-Grouse Habitat Improvement Project Phase IV project area is located in Modoc County, California in the following locations: T46N R7E Sec. 1,6,19,22,23,24,25,29,30,32,36; T46N R8E Sec. 9,10,11,12,13,14,15; and T45N R7E Sec. 2,3,10,11,12,14,15,23,24,25,26,35,36. Current Condition The project area is in the sage steppe ecosystem on the Modoc Plateau. The vegetation in this area is a mixture of low sagebrush, big sagebrush, western juniper, bitterbrush, annual and perennial grasses and forbs. Sagebrush-grasslands are the dominate plant communities, but western juniper now occurs at variable densities throughout the project area. Western juniper, once a minor component of the community, is co-dominant or even dominant in some of these formerly open sagebrush communities. The encroachment of western juniper has made these areas less suitable for Sage-Grouse, as well as moving the vegetative condition away from historic conditions. Juniper encroachment has become more severe in recent years due to changes in agency wild fire suppression activities and climate change. Purpose and Need Maintain and restore suitable habitat for Sage-Grouse in the Clear Lake Active Management Area. The historically sagebrush and native bunchgrass dominated ecosystem has been altered by the encroachment of junipers due to the exclusion of low intensity fires and other factors. Proposed Action The Clear Lake Sage-Grouse Habitat Improvement Project Phase IV proposes to treat up to 10,420 acres of western juniper (Juniperus occidentalis) on Forest system lands. The project proposal consists of four upland habitat units that are located south, southwest, and east of the Clear Lake National Wildlife Refuge. The proposed action would incorporate management recommendations identified in the 2010 Conservation and Recovery Strategy for Sage-Grouse and Sagebrush Ecosystems within the Devil s Garden/Clear Lake Population Management Unit. To meet the Purpose and Need, the following actions are proposed: Hand fell all juniper trees that do not exhibit old growth characteristics. Burn slash concentrations across roughly 30% of the total treatment area. Lop slash throughout the project area. Brush management includes cutting encroaching western juniper, and subsequently treating the slash (cut limbs) generated by the tree cutting work. Juniper trees exhibiting old growth

3 characteristics (large diameter boles, flattened crowns, etc.) and those with cavities or large stick nests would be retained. The definition of old growth juniper is consistent with the Sage Steppe Ecosystem Restoration Strategy (EIS, p49). Existing Condition The 1983 Soil Survey of Modoc National Forest Area, California was used as the basis for interpreting and describing the soil resource. As required in the LRMP the soil survey was fieldverified for vegetation manipulation projects. It was determined, upon field investigation, that the soils were mapped correctly. The Clear Lake Sage-Grouse Habitat Improvement Project Phase IV project encompasses the following SMU: SMU 101 Aikman family, 0 to 2 percent slopes. SMU 109 Alicel family, 5 to 25 percent slopes. SMU 144 Cowiche family, 1 to 10 percent slopes. SMU 146 Cowiche-Simpson families complex, 1 to 15 percent slopes. SMU 154 Deven-Pass Canyon families complex, 1 to 10 percent slopes. SMU 158 Deven-Puls families association, 1 to 15 percent slopes. SMU 184 Indian Creek family, 1 to 5 percent slopes. SMU 185 Indian Creek-Puls-Barnard families complex, 0 to 2 percent slopes. SMU 190 Jacknife-Aikman families association, 0 to 5 percent slopes. SMU 191 Keating-Deven families association, 1 to 20 percent slopes. SMU 201 Lawyer-Elmore families, deep Association, 1 to 20 percent slopes. SMU 210 Lithic Xerorthents, Mesic-xerofluvents, Mesic-Aquolls Association, 0 to 20 percent slopes. SMU 224 Pass Canyon-Fordice-Gwin families Association, 1 to 20 percent slopes. SMU 228 Pass Canyon-Los Gatos families complex, 1 to 20 percent slopes. SMU 236 Puls-Roval-Dishner families complex, 0 to 5 percent slopes. SMU 237 Ridd-Los Gatos-Gwin families association, 5 to 35 percent slopes. SMU 239 Rock outcrop-bakeoven-wenatchee families association, 20 to 60 percent slopes. SMU 268 Supan-Supan deep-pass Canyon families association, 1 to 20 percent slopes. SMU 276 Wrentham-Bakeoven families association, 10 to 40 percent slopes. 3 Table 1. Soil Map Unit Acreages for the Clear Lake Sage-Grouse Habitat Improvement Project Phase IV project.

4 Chandler Unit SMU Acres Doublehead Unit SMU Acres W Horsecamp Unit SMU Acres Mammoth Unit SMU Acres

5 Map 1. Doublehead and Horsecamp Units Soils Map 5

6 Map 2. Mammoth Unit Soils Map

7 Map 3. Chandler Unit Soils Map 7

8 The SMU characteristics in Table 2 should be used to determine management direction. Table 2. Soil Map Unit Characteristics for the Clear Lake Sage-Grouse Habitat Improvement Project Phase IV project. SMU Rooting Depth inches to clayey alluvium to to 40 to weathered to 40 to weathered or to 20 to to 20 to or silica duripan to 20 inches to silica duripan to 40 to silica duripan to alluvium or to 40 to to weathered Erosion Hazard Susceptibility to Burning Damage Surface Horizon Subsurface Horizons Low Silty clay Silty clay Low Gravelly, Gravelly fine sandy Low Loam Clay, Gravelly clay Low Low Loam Clay, Gravelly clay, Silty clay Low Cobbly, Very cobbly Low Cobbly, Very stony clay Low Cobbly clay, Clay Low Cobbly clay, Very stony clay, Cobbly, Silty clay Clay, Clay, Loam, Cobbly clay Clay, Clay Clay Clay, Clay, Gravelly clay, Gravelly silty clay Low Loam, Silty clay Silty clay, Silty clay, Clay, Loam, Sandy, Loamy sand Low Cobbly clay, Clay, Cobbly Stony, Cobbly, Very cobbly Clay, Clay Very cobbly clay, Extremely cobbly clay,

9 210 4 to 40+ to or alluvium to 40 to to 40 to to 20 to or silica duripan to 40 to to 40 to to 40+ to weathered or to 40 to to High, Loam Gravelly, Gravelly clay Low Variable Variable Very cobbly, Very stony, Extremely cobbly Very cobbly, Gravelly Low Very stony clay, Very cobbly, Cobbly sandy clay, Silty clay to High to High Low Cobbly, Gravelly, Very cobbly Very cobbly fine sandy, Gravelly coarse sandy Loam, Very cobbly Very gravelly, Very cobbly fine sandy Loam, Clay, Cobbly clay, Extremely cobbly clay, Loam, Clay, Cobbly clay, Gravelly clay Clay, Clay, Cobbly clay Very cobbly clay, Clay, Gravelly clay, Extremely cobbly clay Extremely gravelly y coarse sand, Fine sandy, Loam Cobbly clay, Gravelly clay, Very gravelly clay, Extremely cobbly clay, Loam, Clay Very gravelly, Very cobbly fine sandy 9

10 Affected Environment Restrictive soil layers as exhibited in the project area increase below ground competition. Shallow restrictive layers present in the project area include a silica duripan, a heavy clay layer, and. With increasing juniper dominance over time, herbaceous vegetation is likely to decrease on sites where there is a restrictive soil layer within inches beneath the surface as is present on these sites. Impermeable layers that restrict water movement also will influence surface water runoff on the site. Enhancing ground cover as a result of cutting junipers will help prevent erosion. Environmental Consequences Proposed Action Direct and Indirect Effects The Proposed Action will revitalize sage-steppe ecosystems through juniper control. This Alternative is to implement the sage steppe restoration strategy which will restore habitat for the Sage-Grouse. This action is needed due to the loss of the sagebrush ecosystem as the density of juniper has altered many sites from sagebrush steppe to juniper dominated woodlands. The cause of this ecological shift is predominately due to anthropogenic changes, and the associated loss of vegetative, habitat, and hydrologic values. Juniper will be cut down that do not meet old growth characteristics on approximately 10,420 acres. The method for restoration will be by hand cutting. With the cutting of juniper, erosion and sedimentation may be reduced by increased perennial grass cover. This should increase the ability of the site to capture and store water. Leaving juniper debris on the ground after cutting can intercept runoff and increase infiltration, as well as reduce evaporative loss of soil water. (1) The juniper boles and branches will be lopped or lopped and scattered on the ground surface with concentrations of down material being burned on approximately 30% of the project area. Concentrations of down material will be burned when conditions permit depending on current fuels conditions and presence of other resource concerns. Limited change in soil structure or infiltration capacity would result from the proposed burning of down material. Juniper reduction from the Clear Lake Sage-Grouse Habitat Improvement Project Phase IV Project not expected to result in detrimental soil disturbance over the allowed 15% of the project area as stated in the LRMP Soils Guidelines. Design Features It is recommended to maintain forest floor litter, organic matter, and small and large woody debris. The reasons include: increasing organic matter to improve site fertility; increasing woody debri to provide a microclimate by increasing shade; which, in turn, would increase soil moisture and decrease soil temperature; increasing woody debris would provide a temporary mechanical

11 barrier to grazers allowing for increased vegetative growth; and retaining organic matter and woody debris on the site to provide protection and habitat for soil biota and wildlife. It is a recommendation to retain and scatter all slash and woody debris from the cut trees. A thick over story of juniper can reduce soil-water-capture and infiltration by limiting the amount of precipitation that reaches the ground. Research indicates that when juniper dominance is reduced, it will result in an increase in herbaceous cover on sites with relatively fine-textured soils; and, hence, a decrease in runoff and soil erosion. Leaving juniper debris on the ground after cutting can intercept runoff and increase infiltration, as well as reduce evaporative loss of soil water. (1) With the cutting of juniper, erosion and sedimentation may be reduced by increased perennial grass cover. This should increase the ability of the site to capture and store water. Consistency with Regulatory Framework Clear Lake Sage-Grouse Habitat Improvement Project Phase IV project Proposed Action Alternative is expected to meet the direction given by the 1991 Modoc National Forest Land and Resource Management Plan, the 2004 Sierra Nevada Forest Plan Amendment Final Supplemental Environmental Impact Statement (SNFPA), the 2008 Sage Steppe Ecosystem Restoration Strategy, appropriate Best Management Practices, and the State Water Resources Control Board requirements. Modoc National Forest Land and Resource Management Plan, 1991 Soils Standards and Guidelines (4-21, 22). 11 Maintain soil productivity by applying guidelines to areas where management prescriptions are applied: land for timber production, range allotments, and other areas where healthy or productive vegetation is desired (e.g., riparian areas and campgrounds). The following guidelines do not apply to administrative sites, system roads or special use areas. Monitor for implementation and effectiveness. Areas not meeting guidelines will be rehabilitated. As a minimum, 85% of areas affected by soil-disturbing activities will not exceed soil property thresholds (Guidelines A-G). A. Forest floor (litter) and large woody debris. Both guidelines below should be met for those forested soils in at least a minimally stocked vegetative condition. - Forest soils are in acceptable condition when: (1) with mechanical site preparation, a minimum of 30% of the soil surface is covered by forest duff which is at least two inches thick (or the existing thickness, if less than two inches) in an intact or nearly intact condition; or (2) for prescribed burns, at least the lower half of the original duff layer which covers 25-50% of the area, should be retained and will be dependent on the erosion hazard potential of the unit (i.e., a higher percentage of duff will be needed where the erosion hazard potential is higher). The intent is to evenly distribute the duff. - For large woody debris management, leave at least 5 logs per acre in an activity area. Up to 20

12 logs per acre may be left when there are no other resource conflicts. The amount specified for retention will depend on the amount of logs available and the number needed to provide nutrient cycling and site productivity while also meeting minimum fuels treatment requirements in the Fire Suppression Difficulty Index (SDI). Preference is for large cull logs at least 16 inches in diameter and about 40 cubic feet in volume. Most logs should be in decomposition classes 3, 4. And 5 (defined in USDA Handbook 553, page 80), except at least two logs per acre should be in class 1 or 2. The class 1 or 2 logs may be the same logs required by the Forest-wide standard for snags and down logs. Smaller logs, stumps and root wads can be substituted when sufficiently large cull logs are not available. Determine the number and size of logs per acre retained through the interdisciplinary process during project level planning. This guideline my be waived in strategic fuel break areas and for safety reasons. B. Soil porosity is at least 90% of its natural condition. To help meet this guideline, both items below should be followed: - During wet soil conditions (as determined on a project level), cease heavy equipment operations or confine equipment and other soil disturbing activities to designated routes. Heavy equipment may be operated (as in dry soil conditions) when (1) sufficient frost exists in the soil (3+ inches); or (2) sufficient snow pack is present (18+ inches); or (3) sufficient surface or subsurface rockiness (more than 60% rocks by volume), or combinations of the above as determined through the interdisciplinary process, is sufficient to support equipment without causing unnecessary soil resource damage. - A soil restoration project will be planned and implemented when: proposed management activities will likely result in less than 90% of the natural porosity being maintained on that portion of land dedicated to vegetative production; current activities are resulting in the above; or past management activities, or the cumulative effect from all these have resulted in the above; and when the most favorable opportunity arises. The most favorable opportunity will be determined through the interdisciplinary process. C. The mineral organic matter in the upper 12 inches of soil should be at least 85% of its natural condition. D. Design management activities not to exceed an average allowable soil loss of one ton per acre per year. This is mainly accomplished by leaving an effective ground cover. The intent is for effective ground cover to be evenly distributed over the soil surface. The amount of effective ground cover needed and the means to meet this will vary by soil type, slope, and planned and applied soil conservation management practices (determined by the erosion hazard rating method , chapter 50). The minimum effective ground cover will be determined through the interdisciplinary process during project planning. E. Treat all degraded watersheds causing active soil degradation in a cost-effective manner and on a priority basis according to beneficial uses. Design improvement activities to meet management objectives. Completion target is two decades. Treat degraded watersheds affecting

13 soil productivity, but not currently in an active state of degradation, within five decades. F. During project planning, verify areas where soil productivity has been degraded. These areas will either be included in the project plan for restoration and improvement, or added to the Watershed Improvement Needs (WIN) program for future treatment. G. Complete an SRI Order 2 or field-verified SRI Order 3 during the planning phase of each sitedisturbing or vegetative manipulation project. Assess impacts of proposed management activities on the soil resource. Develop specific soil mitigation measures and soil conservation management practices for each project site as needed. Range Standards and Guidelines (4-18, 19) 1. Through allotment management planning, manage rangeland vegetation to provide for healthy ecosystems; and to make forage available for livestock, wild horse herds, and wildlife species. F. Manage allotments to protect soil, water, and streamside-dependent resources. Sierra Nevada Forest Plan Amendment Final Supplemental Environmental Impact Statement, 2004 (Volume 1 - Appendix A, pages 358 and 359) Objectives, Standards and Guidelines Maintain suitable habitat for meadow-associated species by using appropriate grazing utilization standards. Degraded meadow (e.g. early seral, with greater than 10 percent bare soil and active erosion) require total rest from grazing until they have recovered and moved to mid or late seral status. 13 Maintain long-term soil productivity; maintain and improve soil fertility, nutrient cycling, soil porosity, hydrologic function, and buffering capacity; minimized erosion. Implement soil quality standards (as outlined in Appendix F). Attain standards for ground cover, compaction, and ground disturbance, so that the risk of sediment delivery to aquatic systems from management activities is minimized. Sage Steppe Ecosystem Restoration Strategy, 2008 Under the provisions of this plan, juniper treatment projects could be implemented to restore the sage-steppe ecosystem on the Modoc National Forest. This could result in the creation of additional forage that could potentially be available in the future for use by herbivores. Other Laws or Regulations Abide by all appropriate contract provisions, Best Management Practices, and the State Water Resources Control Board requirements. Literature Cited

14 (1) Miller, R.F., Bates, J.D., Svejcar, T.J., Pierson, F.B., and Eddleman, L.E Western Juniper Field Guide: Asking the Right Questions to Select Appropriate Management Actions. U.S. Geological Survey Circular p. References Luckow, K.R., and Ahuja, S.P Soil Survey of Modoc National Forest, California. U.S. Department of Agriculture, Forest Service and Natural Resource Conservation Service. 422p. U.S. Department of Agriculture, Forest Service Modoc National Forest Land and Resource Management Plan. Modoc National Forest, Alturas, CA. /s/sue Goheen Date: January 11, 2016 Prepared by Sue Goheen, Modoc National Forest Soil Scientist