I. INTRODUCTION. II. AFFECTED ENVIROMENT - Current Conditions. History of Area and Soils

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2 I. INTRODUCTION History of Area and Soils Soil development was slow in the upper reaches of the Gemmill project area due to steep slopes and old unstable geological formations. In the lower reaches of this area soil development was moderately due to more stable outslope formations. Parent material of mostly metavolcanics and metasediments that have contributed to moderately developed soils. Steep slopes and erosion have produced moderately developed soils that are shallow (<20 inches) to deep (40 to 60 inches) with a thin surface layer. Proposed Action, Purpose & Need The Gemmill Thin project responds to two problems within the Upper Hayfork Creek fifth field watershed and Chanchelulla LSR. 1) There is less late successional old growth (LSOG) habitat than desired; 2) The risk of losing existing and developing LSOG habitat to wildfire is increasing. Soil concerns will focus on soil erosion and detrimental soil disturbance (compaction and soil displacement) as well as minimizing removal of soil nutrients in order to maintain long-term soil productivity. II. AFFECTED ENVIROMENT - Current Conditions The Upper Hayfork watershed is located in the Southern Klamath Mountains (M261Ac) Ecological Subsection of the Klamath Mountains Ecological Section (M261A) of northern California. This subsection comprises an area of the Central Metamorphic Belt of the Klamath Mountains. This area is dominated by Paleozoic metavolcanic and metasedimentary rocks. The climate is temperate and humid. Mass wasting and fluvial erosion are the main geomorphic processes. Soil Information: Soils within the project area have predominately formed in metasedimentary residuum on the upper mountain sideslopes and ridges. Soils formed in these areas are generally shallow (less than 20 inches) to moderately deep (20 to 40 inches) loams to gravelly and very gravelly clay loams (Deadwood, Goulding, Marpa, and Neuns soils). Soils formed in outslope sediments are moderately deep to very deep (greater than 60 inches) loams to gravelly clay loams (Holland and Hugo) see Appendix B (Tables 1 to 5) for soil information within project. Tables 1 and 2 list map units within the project area and various soil descriptions that confirm map unit compositions. Three soils are represented throughout this project area. One with less rock fragments on dormant landslides that has finer surface textures of loam and subsoil textures of clay loam; one with lots of rock fragments that has surface textures of gravelly loam and subsoil textures of very gravelly clay loam; and one with surface textures of sandy loams and subsoil textures of gravelly coarse loams. Steeper 2

3 areas are moderately deep to shallow soils that have slopes less than 35%, and are deep to very deep loams. Tables 3 and 4 list the major soils within the project area, their physical properties, and their ratings for burn damage, compaction, and erosion. Burn damage is controlled by soil pore size and fire intensity. With metasediments (MS) weathering of parent material produces smaller grain sizes and smaller pore sizes that do not allow heat to penetrate deeply into the soil thus reducing effects only to the surface, hence a moderate rating. With rock fragments in the soil greater than 40%, compaction is only at moderate levels but with rock fragments less than 40%, compaction can be high to severe depending on texture. Table 3, shows that Hugo, Holland, and Marpa all have high to severe compaction ratings due to texture and lack of rock fragments. Studies (Powers and Alves, 1999; Gomez and Powers 2004; Luckow 2002; Brais 2002; Rust 2004) have shown that rock fragments greater than 40% act as a matrix or skeleton that resists compressive forces. Erosion hazard is dependent on slope, texture, and rock fragment cover (assuming a bare exposed soil with no cover). Table 3 and 4 show project unit soils (Holland and Hugo) have the highest erosion hazard ratings. Neuns soil has the lowest erosion hazard ratings due to rock fragments on the surface and in the subsoil. In terms of soil erodibility, Hugo soils have the highest adjusted erodibility of.32 (see Table 4), which is an indicator of how easy it will erode. Table 4 show the soils with the highest clay and silt fractions have the slowest permeabilities and saturated flows for subsoil water movement. Holland, Hugo, Marpa soils have the best hydrologic ratings of B, which are moderate runoff rates for medium textured soils. The soils with the highest runoff potentials and slow rates of transmission are Deadwood and Goulding since they are both shallow to hard bedrock and have hydrologic rating of D. Table 5 shows on selected units existing soil cover is very high and duff depth is good for fertility and buffering of temperatures. On the average large woody debris (LWD) is greater than 5 logs per acre, which meets Soil Quality Standards of greater than 5 logs per acre. Fuel amounts are high and a reduction to 5 to 10 tons/acre would be desirable for protection of soil resources from destructive fires. Soil Cover/Erosion: Many land use activities have the potential to cause erosion rates to exceed natural soil erosion or soil formation rates. In order to assess the potential risk of a given soil to erode, an erosion hazard rating (EHR) was developed (R-5 FSH ). Many interrelated factors are evaluated in an EHR system to determine whether land use activities would cause accelerated erosion. The EHR system is designed to assess the relative risk of accelerated sheet and rill erosion. This rating system is based on soil texture, depth, clay percent, infiltration, amount of rock fragments, surface cover (vegetative and surface rocks), slopes, and climate. Risk ratings vary from low to very high with low ratings meaning low probability of surface erosion occurring. Moderate ratings mean that accelerated erosion is likely to occur in most years and water quality 3

4 impacts may occur for the upper part of the moderate numerical range. High to very high EHR ratings mean that accelerated erosion is likely to occur in most years and that erosion control measures should be evaluated. These ratings assume varying amounts of vegetation cover depending on degree of vegetative management. Little past erosion was detected in the project area. Thinning and mastication will leave 50 to 70% of ground cover intact, which equates to low to moderate EHR ratings, only in the Goulding soils did the EHR go high moderates. Current and anticipated EHR levels are listed in Appendix C and are displayed below (Figure 2: Gemmill Project Soil Erosion Hazard Map). Figure 2: Gemmill Project Soil Erosion Hazard Map (bare soil ratings). Figure 2 above, shows the area in orange as having high erosion hazard due to fine textured soils that lack rock fragments. Areas in yellow that are moderately high erosion hazard are shallow gravelly sandy loam soils. Areas in light brown are mixed clay loams and gravelly loams that are moderately deep with moderate erosion rates. Areas in green 4

5 are moderately deep to deep gravelly loams with moderately low erosion rates. These values are for bare surface soils (soils without vegetative cover). Soil Compaction/Porosity: Compaction reduces infiltration, increases runoff, which increases erosion hazard ratings and decreases down site water quality. Detrimental compaction decreases porosity, which decreases tree root elongation during critical growing period thus stressing the tree and decreasing timber site indexes. With stressed trees the stand becomes more likely to develop disease and insect attacks. To deal with the problems of compaction, scientists from the forest service and Pacific Southwest Experimental Station developed a compaction rating criteria and in 1995 the forest service and Pacific Southwest experimental station soil scientists developed Soil Quality Standards (SQS) to set management thresholds for erosion, fertility, and compaction (see Issue of Compaction, 2004). Table 6 below shows the average disturbance and decrease in total porosity for representative transects within selected project units, which are graphically displayed in Graph 1 below. Five 200ft transects were evenly distributed throughout the project area (units 21, 22, 26, 29, 31) on a Hugo loam (map unit 137, Hugo-Neuns complex, 20 to 40% slopes) which had the highest compaction hazard rating (see Table 3). Each transect was stratified according to disturbance into undisturbed, disturbed, and skid trails. Twenty points were sampled per transect measuring bulk density and soil strength. Bulk density is expressed as g/cc3 and is used to calculate porosity, which is expressed as total porosity (or void space) of the soil. Porosity relates to water and gas exchange in the soil necessary for root development. Research has found a decrease in 10% porosity equates to significant decrease in gas and water exchange in soils that affects root growth which equates to detrimental compaction (Powers, et. al. 1995). Soil strength is expressed as kilo-pascals (kpa) of resistance to penetration with a cone penetrometer. It measures the resistance of roots to penetrate soils. When resistance is 2000 kpa root penetration is inhibited and greater than 3000 kpa root penetration ceases (measured at field capacity ideally, but can be measured when dry but values will be much higher). Table 6 shows that 34% of the Gemmill area is in a disturbed state (disturbed and skidtrails) and the rest is undisturbed. The greatest disturbed state is skid-trails, which shows and decrease of 8.2% in total porosity, which is below the SQS threshold of 10%. Table 6: Average Disturbance and porosity for Gemmill Project Area Disturbance Percent Total Porosity Decrease SOS Threshold Undisturbed % Disturbed % Skid Trails % Graph 1 below, sampled when soil was dry in July shows high soils strengths in all samples with a slight increase in the 4 to 6 inch zone and a bigger spike in the 10 to 12 5

6 inch zone. This graph shows some compaction in the 4 to 6 inch zone and old relict compaction in the 9 to 13 inch zone. Tree root development takes place in the spring during tree burst in the 4 to 8 inch zone when soils are moist and at field capacity. When soil becomes dry in late June root growth ceases due to less available water and increasing soil strength. These soil strengths are not unusual for this time of year. Graph 1: Graphic comparison of compaction in disturbed areas and skid trails Gemmill TS Compaction Depth (in) Undisturbed Disturbed Old Skid Trails Soil Strength (kpa) Shasta-Trinity Land Management Plan state that in an even-aged managed stand no more than 15% of the area shall be in a nonproductive state (landings, roads, and main skidtrails). Porosity (an expression of compaction) shall not decrease by 10% over background levels (ST-LMP, Appendix O, Soil Quality Standards). In this area, (see Table 6 and Graph 1 above) skid trails did not exceed porosity thresholds and were at the maximum 8.2% decrease in porosity on 17% of the area. This level of compaction is moderate and not detrimental. Graph 1 above, shows the zone of compaction for recent skid trails is the 4 to 6 inch zone and for old skid trails the 10 to 14 inch zone. Compaction has recovered from old past activities and is below threshold now. Figure 3 below, shows the area in red as having the highest compaction potential where the areas in light green having moderately low compaction potentials. Fine textured soils and lack of rock fragments contribute to this high rating for the Hugo and Holland soils. Coarse textured soils and abundance of rock fragments contribute to a low compaction 6

7 rating for Neuns, Deadwood, and Goulding soils. Given this information, care must be given to the soils in red that have high compaction ratings. Figure 3: Gemmill Project Soil Compaction Hazard Map Soil Fertility/Large Woody Debris: Fuel cover transects (see Table 5) indicate that the dominate cover is the 1 to 3 inch and the 3 to 20 inch class of woody material. Duff thickness ranged from 2 to 4 inches. Average tons/ac for mixed conifer ranged from 22 to 45, for tree/brush stands from 13 to 21 and brush stands from 5 to 7. Large woody debris (LWD) ranged from 10 to 20 trees/ac for mixed conifer stands, for tree/brush stands it ranged from 3 to 8 trees/ac, and for brush areas 1 to 5 logs/ac old decayed class 4 and 5 (see Table 5). It should be pointed out that LWD functions as habitat for vertebrates and invertebrates and not micronutrient banks. Matamala, 2003 and Spear 2003 found that LWD had no significant affect on soil organic matter levels, microbial activity or micronutrient levels. They found the main contributor to organic matter levels was fine tree root decay. Duff and fine slash 7

8 function as cover, invertebrate habitat and substrate, and micronutrient banks. When duff is incorporated into the soil, it becomes a substrate for microbial breakdown and assimilation of micronutrients by plants. Table 5 shows on selected units existing soil cover is very high and duff depth is good for fertility and buffering of temperatures. On the average LWD is greater than 5 logs per acre, which meets Soil Quality Standards (SQS) of greater than 5 logs per acre. Fuel amounts are high and a reduction to 5 to 10 tons/acre would be desirable for protect of soil resources from destructive fires. SQS state that in metavolcanic, metasediment, and nonmarine sediments cover can range from 40 to 70% depending on erosion hazard rating for the particular soil. Mastication will occur on slopes less than 40% and will be used to reduce fuels and provide soil cover. Mastication is really a rearrangement of residue. Mastication reduces the depth of residues and places them nearer to the ground where they can decompose more rapidly. As decomposition increases, organic matter and nutrients are added more quickly to the soil. Soil temperature will increase due to the lowering of canopy in these units but soil moisture will increase so decomposition rates will increase. With some soil incorporation into the masticated chips, decomposition will be accelerated along with the release of carbon dioxide. Important soils nutrients will be released faster (N, P, Ca, Mg, S etc.) and made for plant uptake (Sustaining Site Productivity on Forestlands, 1983). Since cover will be increased by mastication forming a thick organic matter duff, soil microbial activity will be enhanced and soil nutrients will be returned to site. SQS states one should leave 4 to 10 tons per acre of woody material of duff, material 0.25 to 3 inches, and from 3 to 10 inches. These size classes are the most important to protect since they contain the bulk of recyclable soil nutrients. Masticated chips deeper than 4 inches that burns during a wildfire, can cause excessive soil heating when soils are dry with coarse textured soils which can kill plant roots down to 4 inches (Busse, 2005; Raymond, 2005). Most brush fields in this climatic zone that are masticated, will generate from 2 to 3 inches depth of chips over a continuous area so heating thresholds are not likely to be reached. Biomass harvesting will be remove small tree boles and leave tops either to lop and scatter or to hand-pile and burn, with the goal of achieving 4 to 10 tons/acre of surface woody material. Figure 4 below, soil fertility in the Gemmill project area is moderately high to moderately low depending upon the parent material formation and available water holding capacity. Figure 4 shows that Hugo and Holland, have the best soil fertility due to its depth (>40 inches deep), available water-holding capacities (AWC) and finer textured soils (see Table 4). Neuns soils have moderate fertility due to lower AWC values, shallower depths (<40 inches deep), and coarser textured soils. In general, most timber soils have low fertility and most nutrients are recycled from decomposing roots and surface duff leachates that gets incorporated into the soil. Since most roots are in the upper 1 to 2 feet of soil it is very important to protect topsoil from displacement and 8

9 erosion. With erosion, not only is there degraded water quality but also a loss of soil productivity. Figure 4: Gemmill Project Soil Fertility Map III. ALTERNATIVES Soil Resource Bounding Area: The effects of each alternative on the soil resource have been assessed using the Region 5 Soil Quality Standards and the Shasta-Trinity Land Management Plan. 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. Shasta-Trinity Land Management Plan Standards and Guidelines for soils state that in an even-aged managed stand no more than 15% of the area shall be in a nonproductive state (landings, roads, and 9

10 main skid-trails) on matrix lands Shasta-Trinity L.M.P. Chapter 4 section 4-25). These standards apply to the soil project bounding area only. For soil erosion, compaction and soil fertility the soils analysis was bounded only to the project activity units (units #1 to 41). The analysis provided focused on soil productivity and on-site erosion potential. By adhering to the regional soil quality standards (USDA Forest Service, FSH 2509, 1995) for onsite erosion, compaction, and soil fertility, soil productivity is maintained or improved. Three standards will be used as the evaluation criteria to evaluate each alternative: Soil Quality Standards that apply: Soil Stability. Erosion is the detachment, transport, and deposition of soil particles by water, wind or gravity. Vascular plants, soil biotic crusts, and litter cover are the greatest deterrent to surface soil erosion. Visual evidence of surface erosion may include rills, gullies, pedestalling, soil deposition, erosion pavement or loss of the surface "A horizon. Erosion models are also used to predict on-site and off-site soil loss (water erosion prediction project (WEPP) and/or the erosion hazard rating (EHR)) along with soil erosion monitoring stations. Soil Hydrology. This function is assessed by evaluating or observing changes in surface structure, surface pore space, consistence, bulk density, infiltration or penetration resistance using appropriate methods. Increases in bulk density or decreases in porosity results in reduced water infiltration, permeability and plant available moisture. Cone penetrometers and soil core extractors are used to assess this function. Nutrient Cycling. This function is assessed by evaluating the vegetative community composition, litter, coarse woody material, and root distribution. These indicators are directly related to soil organic matter, which is essential in sustaining long-term soil productivity. Soil organic matter provides a carbon and energy source for soil microbes and provides nutrients needed for plant growth. Soil organic matter also provides nutrient storage and capacity for cation and anion exchange. Cover transects are used to assess this function. Soil quality standard measurements (used in matrix Table 6 below): Erosion: (tons/acre) needs to be less than or equal to 1-2 tons/acre depending on slope and parent material which equates to an erosion hazard rating in the low-moderates (4-7). Cover necessary to keep erosion less than 2 tons/acre: o Granitics 90% or greater cover necessary o Metasediments 50 to 70% cover necessary 10

11 Compaction: (g/cm3) based on threshold bulk densities for a particular soil (or less than 10% decrease in porosity) depending on rock fragments and textures and will be expressed as total acres in a compacted state. Fertility or Nutrient Recycling: (tons/acre) Tons of duff and fine slash that is less than 3 inches left after fuel treatment for nutrient recycling (generally 4 to 8 tons/acre which equates to 50 to 70% surface cover). Proposed Alternatives Four alternatives are being proposed for the Gemmill Thin Project: Alternative 1: orginal proposed action, Alternative 2: no action, Alternative 3: diameter limit action, Alternative 4: proposed action. Each alternative will be assessed using the three evaluation criteria developed from the Soil Quality Standards and are displayed in Table 7: Table 7: Soil Quality Standards Matrix for Alternatives Soil Quality Standard Alternative 1 (orginal proposed) Alternative 2 (no action) Alternative 3 (diameter limit) Alternative 4 (proposed) Acres 1,612-1,452 1,452 (Anticipated cover) (50-70% cover) (90-100% cover) (60-80% cover) (50-70% cover) Erosion (erosion hazard rating) Moderate Low Moderate Moderately low Compaction (acres compacted) No detrimental compaction anticipated No detrimental compaction detected (see Table 6) No detrimental compaction anticipated No detrimental compaction anticipated (Miles of roads to be (10.61 miles treated) (0 miles treated) (10.61 miles treated) (10.61 miles treated) decommissioned) Fertility (tons/acre of slash and duff) 5-10 tons/acre tons/acre 7-12 tons/acre 7-12 tons/acre Mitigation Measures: The following mitigation measures are included and should apply: Dedicate no more that 15% of a harvest unit to primary skid trails and landings. Wing subsoil to an estimated 18 inches in depth, mulch, or use available organic material to achieve 2 tons/acre, all temporary roads used in timber-harvest activities. Prevent road runoff from draining onto skid trails and landings. Minimize soil erosion by water-barring all skid trails, mulching with straw or fine slash (achieve 75%+ cover) the last 50 feet of all skid trails where they enter main roads. 11

12 Rip (with winged sub-soiler to 18 inches deep), mulch (2 tons/acre) all landings and primary skid-trails (last 200 feet to landing). When a landing is to be retained, mulch (rice straw or wood chips) to achieve 2 tons/acre of cover. Reuse existing primary skid trails and landings whenever possible. Landings should be constructed to adequately drain with crowned landings and directed drainage with catchments (rock armoring and/or silt fences with straw bales may be used as necessary). All new landing fill slopes and road fill slopes (>100 sq. ft) would be mulched initially, and the mulch would be maintained throughout the life of the project. Landing areas with slopes less than 25% and greater than 1 acre should have natural non-constructed designs with slash covered operating areas for de-limber and loading with short entry road for loading (see design specifications in Appendix----). Retain existing down coarse woody debris (CWD) whenever possible providing the amount of logs does not exceed fuel management objectives. Mechanical skidding equipment is generally restricted to slopes less than 35%. When slopes are >35% and <45% mechanical skidding equipment is restricted to slash covered primary skid trails. Ground-based mechanical equipment will only operate on fine-textured soils (non-rocky) when the soils are dry down to 8 inches from June to the end of October. No wet weather logging on soils with high compaction hazard. Limited operating period (LOP) on units 19, 20, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31, 32, 33, 35, 36, 37, and 39. Post-treatment total soil cover should be between 50 and 70% with at least 50% cover as fine organic matter (duff, plant leaves/needles, fine slash (<3 inch material), etc.). Fuel reduction activities should retain 30-50% of the existing surface duff mat (R5 SQS ). IV. ENVIRONMENTAL CONSEQUENCES Forest soils are generally considered nonrenewable resources with an average formation rate of 0.1 inch/100 years. Recovery time frames for the various components of the soil ecosystem vary from a few years to a 1000 years depending on the intensity and type of disturbance. In 1995, the Forest Service in Region 5 developed soil resource monitoring standards (USFS, 1995) meant to detect changes that would lower soil productivity over a 12

13 rotation which is at least 100 years for nutrient cycling and longer for soil erosion (1000 years). Changes above established thresholds indicate the need for mitigation. This monitoring is based upon the following concepts: 1) management practices create soil disturbance; 2) soil disturbances affect soil and site processes; and 3) soil and site processes control site productivity (Powers et al., 1998). A threshold for detrimental disturbance is defined as a change in any monitoring variable sufficient to trigger a 15% reduction in soil productivity from that of the undisturbed condition. Fifteen percent was chosen because this value was determined to be the smallest change that would be statistically significant. This does not imply that productivity has declined by 15%, but that a detrimental disturbance threshold has been exceeded (Powers et al., 1998). The Regional Soil Quality Standards (USFS, 1995) are meant to be early warning thresholds of impaired soil conditions. Not all changes caused by management are detrimental to the soil resource. The soil quality standards are to be used as interim standards until such time as the Long-Term Soil Productivity installations reach a mature age (Powers et al., 1998) and are able to provide verification of the interim SQS or require modifications of the SQS. The ongoing North American network of Long-Term Soil Productivity installations (Powers and Avers, 1995) have been set up thorough out the U.S. to answer long term soil productivity questions. Scientists from the research branch of the Forest Service and professionals from National Forests are working together in a cooperative national study to find answers to long-term soil productivity. The main objectives are to quantify the effects of soil disturbance on soil productivity, to validate standards and methods for soil quality and monitoring, and to understand the relationships between soil properties, long-term productivity and forest management practices. Findings will show us how changes in site organic matter and soil porosity affect fundamental site processes controlling forest health, productivity, and sustainability. Currently the Soil Quality Standards developed by the region, current research and professional judgment are the standards that we operate on. Alternative 1 Orginal Proposed Action Direct and Indirect Effects Direct effects on the soil ecosystem, by natural or man-caused activities, are primarily soil disturbance, redistribution of organic matter and changes in biological properties. The soil ecosystem properties that are affected are soil volume, soil porosity, soil water availability, soil chemistry, soil biology and ecological diversity (Powers, 1989). Indirect effects on the soil ecosystem are secondary reactions to direct effects. The most common secondary reactions are increased surface erosion, reduction in fertility, and reduced vegetative growth. This alternative treats the thinning acres with track mounted equipment, cable suspension, and helicopter (see Table 7). With planned soil cover of 50 to 70%, erosion will be in the low moderates thus keeping erosion less than 1 tons/acre. This alternative 13

14 focuses on sediment reduction measures to insure cumulative watershed effects do not exceed threshold. Road decommissioning of miles will greatly benefit the soil resources in terms of reducing soil compaction and increasing water infiltration. With erosion mitigations recommendations listed in APPENDIX E direct and indirect effects will be minimal from this project. Concerning compaction, the more acres treated with harvesters and rubber tire skidders when fine-textured soils (soils high in clay) are wet or moist, the more incremental compaction can occur. Harvesting in areas with soils that have high compaction hazards will be limited to dry season only (June to October) as per mitigation measure of limited operating period (see Figure 3 and APPENDIX E). Road decommissioning (10.61 miles) will consist of pulling culverts, ripping, and mulching on selected roads to reduce erosion, increase infiltration, and speed natural recovery of these roads. Fuel treatments will be mastication, lop and scatter, handpile and burn, and jackpot burn for thinned stands, managed plantations, and roadside managed areas. Soil effects of mastication, lop and scatter, hand pile, jackpot burn, and tractor pile are listed in Table 8. Table 8: Fuel treatments and their effect on soils Treatment Mastication Lop & Scatter Hand pile Jackpot Tractor Pile Effects on Soil Fuel rearrangement, increased soil cover, temp., moisture & microbe activity, possible short-term C/N imbalance if too much incorporation. 3 to 10 in material, provides soil cover, breaks down rapidly into fine litter and slow incorporation. Like lop-and-scatter except concentrated, decomposes more slowly, concentrations can burn hot but are only spotty and create mosaic. Concentrated areas of fuel consumed can be hot but are limited on the landscape are mosaic and do not increase overland erosion. Usually large with some topsoil mixed in, some compaction and loss of topsoil if not done properly with brush rakes and good operator. As a general rule 4 to 10 tons per acre of woody material of duff should be left with material being 0.25 to 10 inches in size. These size classes are the most important to protect since they contain the bulk of recyclable soil nutrients. This alternative will leave 5 to 10 tons/acre of woody material for decay and soil fertility. Pile burning (hand pile, jackpot, tractor) will burn fairly hot but of little extent and will create mosaic patterns. Water repellency is only an issue with hot intensity fires, hydrophobic vegetation, and coarse-grained soils. In this project area little coarse-grained soils will be burned. Best Management Practices will be followed in relation to fuel management activities (section Fire Suppression and Fuels Best Management Practices in Water Quality Management for Forest System Lands in California) to insure SQS will be met. 14

15 Mastication will occur on slopes less than 35% and will be used to reduce fuels and provide soil cover. If masticated chips remain on the soil surface soil temperature will decrease due to the insulation affect and soil moisture will increase. With some soil incorporation into the masticated chips, decomposition will be accelerated along with important soils nutrients (N, P, Ca, Mg, S etc.) will be made for plant uptake (Sustaining Site Productivity on Forestlands, 1983). Cumulative Effects This soil resource analysis has been completed in accordance with the CEQ memorandum of June 24, 2005, regarding guidance on the consideration of past actions in cumulative effects analysis. In addition, this analysis incorporates guidance identified in the R5 white paper titled Analysis of Cumulative Effects in NEPA dated 8/4/2005. This cumulative effects analysis quantifies the impact effects as a sum of the direct and indirect impacts of the alternatives considered in addition to the past and foreseeable future actions (which are independent of the alternatives considered) as described in the Cumulative Actions Table in Chapter 2 of the Gemmill EIS. 1. Effects Analysis To analyze the cumulative effects on soils, the unit of measure used to quantify the effects are the regional Soil Quality Standards (SQS) developed and adopted in 1995 (see FSH , R5 Supplement ). These are the appropriate units of measure because they are regional standards that evaluate measurable changes in soil productivity that have been tested and peer reviewed. The direct and indirect effects of implementing the alternatives considered have been disclosed in the previous section of this report. This cumulative effects analysis quantifies the impact effects as a sum of the direct and indirect impacts of the alternatives considered in addition to the past and foreseeable future actions (which are independent of the alternatives considered). 2. Bounding the Effects Cumulative effects on the soil ecosystem have two scales. The first deals with the number and types of management activities occurring within an individual stand over time and their distribution occurring within a project area or watershed over time. Geographic Bounding: The soils analysis provided for this project only considered the specialist project bounding area for Alternative 1 as the project area treatment units. Soil Quality Standards only apply to the affected soils in regards to project unit area erosion, compaction, and fertility of past, present and future planned activities within the project treatment units. Time Frame Bounding: The effect of management on soil recovery is dependent on soil type, climate, moisture, cover and time. By using the Universal Soil Loss Equation (USLE) typical recovery rates 15

16 can be developed that show for erosion, soils with 50 to 70% cover, recovery is in 3 to 5 years (see below Graph 2 USLE Model Recovery). Graph 2. USLE Model Recovery for the Upper Hayfork Ck. Cumulative Watershed USLE Model Recovery "C" factor values Years since disturbance 12 percent soil cover 35 percent soil cover 55 percent soil cover 80 percent soil cover 90 percent soil cover Depending on what effect is measured (erosion or compaction or fertility) will determine recovery rates. Recovery rates for Gemmill Thin Project are listed in Table 9 and Appendix D. The table below shows that there is some short term increases in erosion but over a 3 to 5 year span those rates drop to background (due to falling leaves, braches, needles, grass and forbs). In regards to compaction forest data collected by Pacific Southwest Experimental Station at Redding and the forest soil scientist (Powers, 2005, Rust, 2005, Young, 2005) 1 show in soils that have high clay amounts (Holland and Hugo) severe legacy compaction that is over threshold can last up to 40 years. In soils with less clay and more rock fragments this effect is shorten (Marpa and Neuns). With fertility a slight short-term decrease is due to less duff and dead material but with incorporation this becomes negligible. Also with stand thinning residual trees respond with increased growth, root mass, soil organic matter and an overall increase of soil fertility. Table 9. Recovery rates for the Gemmill Thin Project (with activity being thinning) Recovery Rates for Project Activity (understory thinning) Soils Soil Type Erosion Compaction Fertility Holland 3-5 years years 1-2 years Hugo 3-5 years years 1-2 years Marpa 3-5 years years 1-2 years Neuns 3-5 years 5-10 years 1-2 years 1 See section VIII References 16

17 3. Actions Considered By focusing on the soil quality standards and considering past, planned, and future activities cumulative effects can be evaluated for each alternative within project activity units (see Tables 7, 10). Table 10. Summary of Impacts and Other Management Actions for Alternative 1 Soil Resource Past Direct & Indirect Future Cumulative Erosion Hazard Low Moderate Low Low Compaction Below threshold 10.6 mi road None 10.6 miles decommissioned Hydrologic Good (B) Good (B) Good (B) Good (B) Group Fertility Moderate Moderate Moderate Moderate With erosion control measures implemented, cumulative erosion will be slightly elevated but will go to background levels after 2 to 3 years. This is shown with the recovery curve above and Appendix C & D, which shows calculated surface erosion rates (WEPP erosion model) 2 for predevelopment conditions, severe wildfire, clear-cut harvest, thinning harvest, prescribed fire, skid-trails, landings, and post harvest recovery rates. The WEPP model shows onsite erosion rates for planned thinning (0.25 t/a) are well below 1 ton/acre and sediment delivery rates are very low (0.18 t/a) and are similar to predevelopment levels of (0.09 t/a). In comparison clear-cuts on these soils with similar site conditions are only elevated by 30% (0.65 t/a) vs. a severe wildfire where erosion rates are in excess of tons/acre depending on soil type. Landings (60 ea planned less than.5ac ea.) have rates that are similar to clear-cuts (0.34 t/a) and when mulched the rates are negligible (0.02 t/a). The same holds true of skid trails that are mulched or slash covered (from 39.9 pre to 0.64 t/a post). All of these units, roads, skid-trails, landings, and prescribed burns have generous forest buffers that limit sediment delivery into waterways. For Alternative 1, with compaction mitigation measures for all units, infiltration will not be impeded and overall soil quality will be maintained. Hydrologic function will be improved due to road decommissioning mitigation measures built into this alternative, which will improve drainage and lessen surface runoff. 2 The Water Erosion Prediction Project (WEPP) soil erosion model was developed by an interagency group of scientists including the USDA's Agricultural Research Service (ARS), Natural Resources Conservation Service, Forest Service, the Dept. of Interior s Bureau of Land Management and US Geological Survey. Scientists from these agencies throughout the United States have been working since 1985 to develop this erosion prediction model to replace the Universal Soil Loss Equation (USLE) for various land management activities (timber harvesting, roads, grazing, fuel reduction, prescribed fire and wildfire). 17

18 For Alternative 1, future foreseeable action of burning (as listed in Cumulative Actions Table X) brush fields will be lightly burned and cover will be greater than 50% levels which will yield values in the moderate EHR range. Brush fields contain vegetation that produce water repellency (Chamise, Manazita, Buckbrush) but these areas will be burned lightly to reduce flashy fuels. The effects of burning will be limited to low intensity burns that create mosaic landscapes to reduce fuel loads. Future foreseeable underburning will consume moderate amounts of surface slash but shallow burning penetration will have minimal effect on soil organic matter and duff consumption. Burning done with a low to moderate prescription will not affect soil fertility significantly and will be done with the assurance of protecting soil cover, soil organic matter and consumption of no more that 50 percent of soil duff. Soil fertility will be increased due to better infiltration and tree growth, which equates to more fine root development and increase of organic matter in the soil. In Mediterranean climates 3 the bulk of soil nutrients reside in the soil of which is released slowly over time. Root decay has been shown to be one of the main contributors to soil organic matter. Soil organic matter acts as sinks for soil nutrients, and are readily available for breakdown by soil microorganisms and incorporation. Maintaining duff and fine slash of at least 50% of the area is crucial to maintaining soil health and fertility. Post harvest fuel treatments will be moderate and soil health will be adequately protected. For Alternative 1, future foreseeable actions as listed in Cumulative Actions Table X are outside soil bounding area except prescribed burning that has been analyzed above. Alternative 2 No Action Current soil conditions for the Gemmill action area watersheds are landscapes with areas of moderate past use (Hall City sub-watershed) to areas of low past use (Chanchelulla, Wilson, and Goods sub-watersheds). Soils are mostly metavolcanic and on lower rolling hillslopes old dormant landslide deposits. Metavolcanic soils are moderately susceptible to erosion and past use indicates that erosion has been low to moderate. Currently these areas are stabilized and erosion is at low rates for metavolcanic. The landslide deposits have had some erosion due to placer miming and stripping in the Hall City subwatershed. These areas have been logged in the past thus causing more erosion and compaction. Currently these areas have good cover, erosion is at moderately low levels, and compaction levels have recovered and are below SQS thresholds (see Appendix C, Table 6, and Graph 1). If a stand-replacing fire were to occur in the Gemmill action area severe erosion would occur on both metavolcanic soils and the fine textured landslide sediments (see Appendix C and D). A stand-replacing fire would remove soil cover and cause organic matter destruction especially in the topsoil. These factors would cause sheet and rill erosion in the productive topsoil at rates as high 74 tons/acre far exceeding soil formation 3 Mediterranean climate warm dry summers and cool moist winters. 18

19 rates of 1 to 2 tons/acre/year. This alternative would not treat excessive fuel accumulation. Erosion rates would be excessive if a major fire occurred, thus necessitating the need a for fuel reduction program in these areas to protect soil resources. Alternative 3 Diameter Limit Direct and Indirect Effects This alternative focuses on removing every tree less than 18 inches in diameter with feller-bunchers and cable suspension. The effects on overall soil erosion and compaction will be similar to Alternative 1 but stand health would not be effectively treated and soil fertility could be affected with increased root diseases in this area. Road decommissioning will be the same as alternative 1, which will have a positive direct and indirect effect by increasing infiltration and reducing road erosion. With less area thinned a large wildfire could burn these areas more severely thus increasing erosion (see Table 7 & Appendix D). Cumulative Effects This soil resource analysis has been completed in accordance with the CEQ memorandum of June 24, 2005, regarding guidance on the consideration of past actions in cumulative effects analysis. In addition, this analysis incorporates guidance identified in the R5 white paper titled Analysis of Cumulative Effects in NEPA dated 8/4/ Effects Analysis To analyze the cumulative effects on soils, the unit of measure used to quantify the effects are the regional Soil Quality Standards (SQS) developed and adopted in 1995 (see FSH , R5 Supplement ). These are the appropriate units of measure because they are regional standards that evaluate measurable changes in soil productivity that have been tested and peer reviewed. The direct and indirect effects of implementing the alternatives considered have been disclosed in the previous section of this report. This cumulative effects analysis quantifies the impact effects as a sum of the direct and indirect impacts of the alternatives considered in addition to the past and foreseeable future actions (which are independent of the alternatives considered). 2. Bounding the Effects Are the same as in Alternative 1 in regards to geographic bounding and time frame. 3. Actions Considered By focusing on the soil quality standards and considering past, planned, and future activities cumulative effects can be evaluated for alternative 3 (see Tables 7, 11). 19

20 Table 11. Summary of Impacts and Other Management Actions for Alternative 3 Soil Resource Past Direct & Indirect Future Cumulative Erosion Hazard Low Moderate Low Low Compaction Below threshold 10.6 mi road decommissioned None 10.6 miles (decompaction) Hydrologic Good (B) Good (B) Good (B) Good (B) Group Fertility Moderate Moderate Moderate Moderate Erosion control measures implemented, cumulative erosion will be slightly less than Alternative 1 but will go to background levels after 2 to 3 years. This is shown with the recovery curve above and Appendix D, which shows calculated surface erosion rates (WEPP erosion model) 4 for predevelopment conditions, severe wildfire, clear-cut harvest, thinning harvest, prescribed fire, skid-trails, landings, and post harvest recovery rates. For Alternative 3, with compaction mitigation measures for all units, infiltration will not be impeded and overall soil quality will be maintained. Hydrologic function will be improved due to road decommissioning mitigation measures built into this alternative, which will improve drainage and lessen surface runoff. Future foreseeable action of burning (as listed in Cumulative Actions Table X) brush fields will be lightly burned and cover will be around 50% levels which will yield values in the moderate EHR range. Broadcast burning brush fields contain vegetation that produce water repellency (Chamise, Manazita, Buckbrush) but these areas will be burned lightly to reduce flashy fuels. Underburning will consume moderate amounts of surface slash but shallow burning penetration will have minimal effect on soil organic matter and duff consumption. Burning done with a low to moderate prescription will not affect soil fertility significantly and will be done with the assurance of protecting soil cover, soil organic matter and consumption of no more that 50 percent of soil duff. Soil fertility will be increased due to better infiltration and tree growth, which equates to more fine root development and increase of organic matter in the soil. For this alternative, only trees less than 18 inches will be removed increasing growth on healthy stands but will have less benefit for unhealthy stands with root rot and stem rot disease. With 4 The Water Erosion Prediction Project (WEPP) soil erosion model was developed by an interagency group of scientists including the USDA's Agricultural Research Service (ARS), Natural Resources Conservation Service, Forest Service, the Dept. of Interior s Bureau of Land Management and US Geological Survey. Scientists from these agencies throughout the United States have been working since 1985 to develop this erosion prediction model to replace the Universal Soil Loss Equation (USLE) for various land management activities (timber harvesting, roads, grazing, fuel reduction, prescribed fire and wildfire). 20

21 unhealthy stands these areas will be more susceptible to fire due to dead material accumulation. For Alternative 3, future foreseeable actions as listed in Cumulative Actions Table X are outside soil bounding area except prescribed burning that has been analyzed above. Alternative 4 Proposed Action Direct and Indirect Effects for Alternative 4 This alternative proposes thinning using track mounted equipment, cable suspension, and helicopter; along with post-harvest and other hazardous fuels reduction. Post-project soil cover will be maintained at 50 to 70%, therefore erosion will be low to moderate and less than 1 ton per acre. Harvesting in areas with soils that have severe compaction hazards will only occur during the driest part of the year, June to October, as described in resource protection measures for units 19 to 33, 35 to 37, and unit 39. Soil effects of postharvest fuels reduction including mastication, lop and scatter, and hand pile are summarized in Table Road decommissioning of 10.6 miles would greatly benefit the soils resource in terms of reducing soil compaction and increasing water infiltration. Road decommissioning will consist of pulling culverts, ripping, and mulching on selected roads to reduce erosion, increase infiltration, and speed natural recovery of these roads. Due to incorporation of appropriate resource protection measures (Chapter 2) and Best Management Practices (Appendix O), direct and indirect effects to soils will be minimal from this project. Table Fuel treatments and their effect on soils Treatment Mastication Lop & Scatter Hand pile Effects on Soil Fuel rearrangement, increased soil cover, temp., moisture & microbe activity, possible short-term C/N imbalance if too much incorporation. 3 to 10 in material, provides soil cover, breaks down rapidly into fine litter and slow incorporation. Like lop-and-scatter except concentrated, decomposes more slowly, concentrations can burn hot but are only spotty and create mosaic. As a general rule, 4 to 10 tons per acre of woody material of duff would be left with material being 0.25 to 10 inches in size. These size classes are the most important to retain since they contain the bulk of recyclable soil nutrients. Retaining 5 to 10 tons per acre of woody material with this alternative will maintain natural decay processes and soil fertility. Hand pile burning will be fairly hot in concentrated areas of small extent and will create mosaic patterns in terms of soils effects. Water-repellency is only an issue with high intensity fires, hydrophobic vegetation (i.e., chaparral and chemise spp.), and coarse-grained soils. In this project area little coarse-grained soils will be burned, and soil water-repellency is not expected. Mastication will occur on slopes less than 35% and will be used to reduce fuels and provide soil cover. If the masticated chips remain on the soil 21

22 surface, soil temperature will decrease due to the insulation affect of scattered material and soil moisture will increase. With some soil incorporation into the masticated chips, decomposition will be accelerated and plant uptake of important soils nutrients (N, P, Ca, Mg, S etc.) will be encouraged. 5 Cumulative Effects For Alternative 4, implementation of resource protection measures and BMPs ensure that detrimental compaction will not take place, infiltration will not be impeded and overall soil quality will be maintained. Future foreseeable thinning in the analysis area are outside soils bounding area (project units) and would not cause soil-related effects that would be cumulative with the effects of this project. Future foreseeable prescribed burning in Wilson and Hall City watersheds (Gemmill Fuels Project) would be accomplished with a low to moderate burn prescription and would not affect soil fertility significantly. The effects of burning will be limited to low intensity burns that create mosaic landscapes to reduce fuel loads. Light duff consumption and shallow burning penetration has minimal effect on soil organic matter and duff consumption. Burning would be done with the assurance of protecting soil cover, soil organic matter, and consumption of no more that 50 percent of soil duff. Brush fields do contain vegetation that produce water repellency (Chemise, Manzanita, Buckbrush), therefore these areas will only be burned with a light prescription to reduce flashy fuels. Best Management Practices (BMPs) will be incorporated in future Forest Service fuel management activities to insure SQS will be met. Soil fertility will be increased due to better infiltration and tree growth, which equates to more fine root development and increase of organic matter in the soil. In Mediterranean climates6 the bulk of soil nutrients reside in the soil and duff, of which is released slowly over time. Root decay has been shown to be one of the main contributors to soil organic matter. Soil organic matter acts as a sink for soil nutrients that are readily available for breakdown by soil microorganisms and incorporation. Maintaining at least 50% duff and fine slash in an area is crucial to maintaining soil health and fertility. Post harvest fuel treatments will be moderate and soil health will be adequately protected. Conclusion: There are no cumulative effects on soils with this project. Within the project activity units (soil resource bounding area) past effects are out of the range of time and space since past effects are healed. Future foreseeable project of burning within the soil resource bounding area are within the SQS standards so effects will be negligible and not cumulative. Therefore the only cumulative effect could be a large stand-replacing fire that would cause accelerated erosion that would far exceed SQS thresholds (see 5 Powers (1983) 6 Mediterranean climate warm dry summers and cool moist winters. 22

23 Appendix C & D). Given current site conditions, Alternative 1 reduces fire risk to the greatest extent by treating the most ground. With alternative 2, erosion could be elevated due to increased fire risk and soil fertility levels will be at risk due to wildfire effect of extreme soil heating and soil organic matter destruction (see Table 7 & Appendix C & D). With alternative 3, stand health will not be effectively treated and will be susceptible to stand replacing fires (see Table 7 & 11). Alternative 4 reduces fire risk by treating the most ground and has the least soil impacts. Addendum to Gemmill Thin DEIS cumulative effects analysis: There are three new projects as well as a wildfire (Telephone Fire, 2008) that were not foreseeable when the analysis for the Gemmill DEIS was completed; as a result there is a need to update the cumulative effects analyses for all resources to include relevant actions/effects of these projects. The three new projects (see Figure 5) are: 1) Westside plantation thinning 2) Westside watershed restoration 3) Forest-wide travel management plan. All of the listed fires (Telephone fire) and future foreseeable projects (Westside plantation thin, Westside watershed restoration, and forest travel management) are outside of the soil bounding for time and space for soil cumulative effects. Soil bounding for the Gemmill project was the project unit boundaries only. The Telephone fire or any foreseeable projects will not overlap these units so their will be no additional cumulative effects for project unit soils. 23

24 Figure1. Gemmill Analysis Area 2008 wildfires and new foreseeable actions 24