S.F. Stillaguamish Vegetation Project Silviculture. Samantha Chang, Certified Silviculturist September 8, 2017

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1 MOUNT BAKER-SNOQUALMIE NATIONAL FOREST SPECIALIST REPORT OUTLINE ENVIRONMENTAL ASSESSMENT S.F. Stillaguamish Vegetation Project Silviculture Samantha Chang, Certified Silviculturist September 8, Applicable Laws, Regulations, and Policies The National Forest Management Act of 1976 Mt. Baker-Snoqualmie National Forest Land and Resource Management Plan (Forest Plan, as amended) Standards and Guidelines for Management of Habitat for Late Successional and Old Growth Forest Related Species within the Range of the Northern Spotted Owl, including the Aquatic Conservation Strategy Forest Service Handbook , Section 32.1 directs that a financial analysis shall be completed for each timber sale project alternative during environmental analysis. As defined by Forest Service Handbook , Section 13, a financial analysis provides a comparison of anticipated costs and revenues that are part of Forest Service monetary transactions. Forest Service Manual Policy directs National Forests to use only those silvicultural practices that are best suited to the land management objectives for the area; ensure practices are applied so as to sustainably manage forest vegetation resources, as directed in the land management plan; and prescribe treatments that are practical in terms of the cost of preparation, administration, transportation systems, and logging methods. In Section 2478 Silvicultural Examinations, Prescriptions, and Evaluations, FSM Policy directs that on National Forest System lands, all silvicultural activities that cut, burn, establish, or otherwise modify forest vegetation, must have a silvicultural diagnosis and prescription prepared or reviewed by a certified Silviculturist prior to implementing the project or treatment. FSM Diagnosis of Treatment Needs states that the diagnosis compares the existing conditions to the desired conditions to determine treatment options to achieve the management objectives, supports the proposed action as well as the purpose and need for action for silvicultural projects, and provides information for alternative development and evaluation of the effects on the forest vegetation. 2. Relevant Standards and Guidelines 1994 Record of Decision NWFP 1 of 23

2 Late-Successional Reserves Relevant Standards and Guidelines: No harvest is allowed in stands over 80 years old. Thinning may occur in stands up to 80 years old regardless of the origin of the stands. The purpose of silvicultural treatments is to benefit the creation and maintenance of late-successional forest conditions. Thinning these stands can open up the canopy, thereby increasing diversity of plants and animals and hastening transition to a forest with mature characteristics (1994 ROD, p. C-12). Riparian Reserves Relevant Standards and Guidelines: TM-1. Prohibit timber harvest, including fuelwood cutting, in Riparian Reserves, except to control stocking, reestablish and manage stands, and acquire desired vegetation characteristics needed to attain Aquatic Conservation Strategy objectives (1994 ROD, p. C-32) Forest Plan Forest-Wide Standards & Guidelines Timber Relevant Standards and Guidelines: Provide for the production of timber on lands classified as suitable for timber production consistent with various resource objectives, environmental constraints, and considering cost efficiency (MBS Forest Plan, p ). Favor the regeneration and management of western redcedar on those sites where it now occurs and on sites where environmental conditions are such that successful establishment and management would occur (MBS Forest Plan, p ). 3. Other Programmatic Direction Forest-Wide Late Successional Reserve Assessment, Mt. Baker-Snoqualmie National Forest, September The project area is within LSR 116, which was designed to include habitat with numerous marbled murrelet detections and to improve connectivity between areas of suitable owl habitat. 2 of 23

3 The LSR s current projection of providing habitat capable of supporting 19 owl pairs deviates greatly from the projection of supporting 26 nesting pairs when habitat conditions are recovered (LSRA p. 38). 4. Definitions of Technical Terms (if needed) Basal area (BA) The cross-sectional area of a tree trunk at breast height (4.5 feet above ground), expressed in square feet. Benefit/Cost Ratio The value of benefits divided by the value of costs. It is a simple gauge of the relative efficiency of amounts of investment and operating funds to produce benefits. Canopy closure The ground area covered by the vertical projection of crown perimeters and commonly expressed as a percent of total ground area. Codominant A tree whose crown helps to form the general level of the main canopy. Commercial thinning An intermediate treatment to improve residual tree growth which harvests timber that is suitable for production of commercially valued products, generally dimensional lumber or plywood veneer. Crown The part of a tree bearing live branches and foliage. Diameter at breast height (DBH) The diameter of a tree bole measured perpendicular to the trunk at 4.5 feet above ground, expressed in inches. Height above ground is measured from the uphill side if on a slope. Dominant A tree whose crown extends above the general level of the main canopy. Ground-based yarding Timber harvesting system in which logs are transported from stump to landing using heavy equipment that travels on tires or tracks (tractor, skidder, loader, forwarder, etc.) that either drag or carry the logs. Use is generally restricted to less than 35% due to equipment limitations and soil protection measures. Plant association A plant community type based on land management potential, successional patterns, species composition, and potential natural vegetation. Pre-commercial thinning An intermediate treatment to improve residual tree growth that does not produce harvested materials with commercial value. Relative density (RD) A measure of stand density relative to established reference levels, where RD = BA/(QMD^1/2) (Curtis, 1982). Resilience The ability of a social or ecological system to absorb disturbances while retaining the same basic structure and ways of functioning, the capacity for self-organization, and the capacity to adapt to stress and change. 3 of 23

4 Restoration The process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed. Ecological restoration focuses on reestablishing the composition, structure, pattern, and ecological processes necessary to facilitate terrestrial and aquatic ecosystems sustainability, resilience, and health under current and future conditions. Quadratic mean diameter (QMD) The diameter corresponding to the mean basal area of a stand. Skyline yarding Timber harvesting system in which logs are transported from stump to landing by full or partial suspension from a steel cable (skyline) suspended between a yarder and tail tree, tailhold stump, or other anchor point. Soil disturbance is generally lower than ground-based yarding due to the suspension and absence of heavy equipment travel within the stand. Silviculture The art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society on a sustainable basis. Silvicultural Prescription A document written or approved by a certified silviculturist that describes management activities needed to implement silvicultural treatment or treatment sequence. The prescription documents the results of an analysis of present and anticipated site conditions and management direction. It also describes the desired future vegetation conditions in measurable terms. It documents a planned series of treatments designed to change current stand structure and composition to one that meets management goals. The prescription normally considers ecological, economic, and societal objectives and constraints. Stand A contiguous group of trees sufficiently uniform in age-class distribution, composition, and structure, and growing on a site of sufficiently uniform quality, to be a distinguishable unit. Stand density A measure of the degree of crowding of trees within stocked areas. Thinning A silvicultural treatment made to reduce stand density of trees primarily to improve growth, enhance forest health, or to recover potential mortality. 5. Management Requirements and Mitigation Measures There are no mitigation measures for the timber resource in this project. 6. Analysis Methodology, Assumptions Stand examination plot data was collected in 2015 and 2016 for 32 of the stands proposed for commercial thinning in the S.F. Stillaguamish Vegetation Project. Data was recorded through Common Stand Exam software and uploaded to the FSVeg database and used for growth and yield modeling with the Forest Vegetation Simulator program (FVS) using the West Cascades Variant. Stand growth and yield was modeled for the individual stands for which data was collected, and averaged by vegetation zone to project expected growth and yield for stands proposed for commercial thinning in the Project. Stand examination plot data was not collected for pre-commercial stands. A combination of stand examination data, modeling, field 4 of 23

5 reconnaissance, aerial photography and remote sensing data interpretation, and historic records were used to analyze the stands within this project. FVS output was used to compare predicted effects of each alternative. For estimates of stand density, growth, and species composition trees 6 inches DBH and greater were considered. Volume estimates are computed for trees 7 inches DBH and greater for consistency with current market demand for minimum merchantable log size. Tree regeneration and growth of existing seedlings were not modeled, as modeling of treatments based upon a target relative density are skewed when seedling and sapling size trees are included in the calculation of relative density, and both natural regeneration and understory vegetation development are difficult to model with current FVS software. Cost efficiency analysis was done using FVS volume estimates, current regional log prices, road reconstruction and maintenance cost estimates (see Engineering Specialist Report), approximate timber harvest and contract costs from recent comparable timber sales, and adjustment for various factors based on an analysis of bid statistics from comparable timber sales on the Mt. Baker-Snoqualmie National Forest from 2009 to present. This report provides an assessment of economic viability of proposed timber harvest based upon those estimates. Actual timber sale bid values would be dependent on timber cruise volume estimates, contract requirements and market conditions. Pre-commercial thinning, also referred to as non-commercial thinning in the Environmental Analysis, is not included in the cost efficiency analysis for proposed timber harvest. Timber sale receipts retained for resource improvements through the Knutsen- Vandenberg Act or allocated funds for Stand Improvement could be used to fund noncommercial treatments. Ecosystem services such as water supply, wildlife habitat, air quality, and visual quality have complex values that are difficult to quantify, and therefore are not considered in this cost efficiency analysis. Costs of planning, timber sale preparation, and timber sale administration are not considered in the estimated timber sale values. Direct and indirect effects on forest vegetation were analyzed within the proposed treatment stands in the S.F. Stillaguamish Vegetation Project. Cumulative effects were analyzed within the South Fork Stillaguamish watershed. 7. Affected Environment Need for Treatment The time needed for natural development from an early seral stage to late seral or old forest stage is estimated at years for Western Hemlock Zone forests, and years within the Silver Fir Zone. Old forest structure, which likely provides the highest quality habitat for species associated with late seral or old growth forests due to the persistence and size of down logs, is complete at approximately 450 years old (LSRA, p. 26). Past timber harvesting created stands in younger age classes which are densely stocked and structurally simple, and lack the complex old forest structure needed as quality habitat for those species. The treatments proposed in this project are designed to expedite development of desired structural characteristics to improve habitat capacity for northern spotted owls and marbled murrelets through variable density thinning approaches that have been applied in other Late Successional Reserves on the MBS. 5 of 23

6 Appropriately designed thinning treatments in dense, young stands can provide growing conditions that approximate those historically found in the early development of old-growth stands (Hayes, et al, 1997) and to speed development of old-growth characteristics (Tappeiner, et al, 1997). The function of thinning for these objectives is to promote growth of vigorous dominant trees and accentuate heterogeneity of tree sizes that hastens development of old-growth structure (Acker, et al, 1998). Commercial thinning can initiate and promote tree regeneration, shrub growth, and the development of multi-storied stands (Bailey, et al, 1998). Thinning and gap creation increase understory shrub size, and flower and fruit production (Wender, et al, 2004). Although the full suite of conditions that develop in old-growth forests over long periods of time cannot be expected to accelerate through a single thinning treatment, some select characteristics (such as tree diameter, density, canopy structure, species composition, and vegetative cover) can be improved in the near term while others continue to gradually develop. Promotion of large branch diameters is a goal of the treatments, as they provide nesting platforms for marbled murrelets when of sufficient girth, covered with lichens, or contorted into witch s brooms by dwarf mistletoe infection. Branch radial growth is influenced by light availability (either due to crowding or relative height in the crown), and is positively correlated to tree basal area growth, making individual branches highly responsive to changes in stand conditions imposed by silvicultural treatments (Weiskittel, et al, 2007). Heavier commercial thinning results in more live branches and larger branch diameters on remaining Douglas-fir trees that are more suitable for nesting platforms, compared to lighter thinning or no thinning (Dykstra, et al, 2016). Proposed Treatment Stands Stands proposed for treatment in the S.F. Stillaguamish Vegetation Project regenerated both naturally and with planting following clearcut harvesting. Stand year of origin for stands proposed for commercial thinning range from Some of the stands were precommercially thinned. There are approximately 6,958 acres of stands suitable for commercial thinning in the project area. Stands proposed for non-commercial thinning were clearcut as recently as There are approximately 5,727 acres of stands suitable for non-commercial thinning in the project area. Adjacent and surrounding stands are a combination of mature, oldgrowth, and younger stands. The stands are located primarily within the Western Hemlock Zone, with some upper areas in the Silver Fir Zone (see Table 1). Most stands proposed for treatment have moderate to moderately high productivity and stockability (Henderson et al., 1992). Elevations range from 1,000 to 4,000 feet above sea level. Table 1. Approximation of Plant Associations in Stands Proposed for Commercial Thinning. Vegetation Zone Plant Association Timber Productivity Western Hemlock Zone Western Hemlock/Alaska Huckleberry-Swordfern Western Hemlock/Swordfern- Foamflower Western Hemlock/ Alaska Huckleberry Moderate to Moderately high Stockability Percentage of Plots High 33% Moderately high High 25% Moderate Moderate 23% Western Hemlock/Devil s Moderate to Low 5% 6 of 23

7 Silver Fir Zone Club-Ladyfern Western Hemlock/Swordfern- Oregongrape Silver Fir/ Devil s Club- Alaska Huckleberry High Moderately high High 4% Moderate Moderate to High 4% Silver Fir/Alaska Huckleberry Low to Moderate Moderate to High 2% Habitat quality in this LSR is below the level needed for old-growth dependent species because much of the area is in younger stand ages with dense, homogenous stands that do not provide necessary habitat characteristics like cavity and branch nesting structures and suitable forage. Current habitat capacity for nesting pairs of northern spotted owls is estimated at about 73% of potential capacity when habitat conditions are recovered (LSRA p. 38). Species Composition Western hemlock, Douglas-fir, and Pacific silver fir are the most prevalent tree species in the overstory. Western redcedar and red alder are also present in the overstory, along with minor amounts of Pacific yew, Sitka spruce, and bigleaf maple. Advance regeneration of trees in the understory consists of hemlock and silver fir, with smaller numbers of western redcedar. Understory vegetation is limited by lack of available light, but is more abundant where small gaps exist in the tree canopy. Understory species include red huckleberry, Alaska huckleberry, Oregon grape, salmonberry, trailing blackberry, swordfern, bracken fern, deer fern, devil s club, and foamflower. Patches of red alder are located in areas of relatively recent past disturbance, such as along the channel migration zone of the South Fork Stillaguamish River and other smaller channels, landslides, and road construction areas. In the alder patches shade-tolerant conifer species such as hemlock and cedar are emerging through the understory as the alders mature. Lacking new disturbances that expose bare soil the stands will most likely revert to conifer-dominated forest in the long term as the alders reach maturity and decay. Areas of alder along channel migration zones will most likely persist over time due to periodic disturbance caused by flood events. Disturbance History Timber harvest and land clearing beginning with Euro-American settlement is the most evident disturbance factor affecting vegetation in stands within the project area. Early settlement for mining and the associated railroad activity led to relatively small-scale clearing for townsites and occasional fires near developments. Large-scale natural disturbance factors include landscapescale stand-replacing fires that have occurred centuries apart, avalanches, landslides, and flooding along the river. Fire was the main factor affecting the development of forest stands, with much of the project area growing after major fires that occurred in 1308, 1508, and The area around Mt. Pilchuck is colder and wetter relative to elevation than any other area of the Mt. Baker-Snoqualmie National Forest, and features some of the oldest trees dating to over 1,000 years due to the lack of more recent stand-replacing fires. Following commercial timber harvest, prescribed burns were used following clearcut harvest for slash treatment and site preparation before planting. Windthrow appears to be limited in extent and frequency, as tip-up mounds are 7 of 23

8 present but few areas of extensive windthrown trees can be found. Severe winter storms can cause small patches of windthrow, such as areas of saturated soils along the Mountain Loop Highway several years ago and Heather Lake Trail in the winter of Past forest management practices were primarily even-age silviculture for timber production objectives. Stands were clearcut and routinely burned for slash reduction and site preparation for planting, including yarding of cull logs in the 1970s and early 1980s in hopes of increased utilization of biomass in the piled unmerchatable material, or PUM decks, at landings. As the market for such biomass did not materialize, many of the PUM decks still remain at landings and have been the source of human-caused fires at dispersed recreation sites in recent years. Timber management was focused on conifer production, and natural regeneration of hardwoods was reduced through prescribed burns and pre-commercial thinning. Natural regeneration was supplemented with predominately Douglas-fir seedlings in the Western Hemlock and Silver Fir zones, including offsite stock prior to the 1980s. The use of poorly matched seed stock and species contributed to limited regeneration or the need to replant in some cases (USDA, 1995) and is evident in the predominance of western hemlock in the stands at present. Forest Health Forest pathogens that contribute to tree mortality and damage to conifer trees in the project area include Douglas-fir beetle, bark stripping by black bears, dwarf hemlock mistletoe branch and stem deformities, hemlock looper, hemlock woolly adelgid, fir engraver beetle, heart decay, and patches of root disease. Past bear damage was found in 31% of stands. Young trees with thin bark are most susceptible to bark stripping by black bears, and bear damage may be ongoing in non-commercial age stands in the project area. Dwarf hemlock mistletoe was found in 19% of stands. Stand examination plots, which were completed following the summer drought of 2015, found Douglas-fir beetle activity in 28% of stands surveyed, and 41% of the stands that had Douglas-fir trees in the plots. The combination of root disease, drought, and Douglas-fir beetles appears to be contributing to limited mortality in some areas (Dickinson, 2016). Douglas-fir beetle activity appeared to subside to lower background levels with the return to more typical seasonal precipitation patterns in summer Hemlock looper caterpillars have caused varying levels of damage and mortality in the project area. A hemlock looper outbreak in 1993 and 1994 caused over 10,000 acres of defoliation in the South Fork Stillaguamish drainage, including about 4,000 acres in the Green Mountain Analysis Area. That outbreak caused nearly 1,000 acres of tree mortality along Canyon Creek, followed by stand regeneration. Looper outbreaks occur in cycles averaging about 10 years apart, and tend to occur in the same areas over time as they prefer older forest stands with a high proportion of western hemlock and lower elevations with gentle slopes. The Green Mountain area was also extensively affected in 2005 and 2006 by both hemlock looper defoliation and drought-related hemlock dieback. An evaluation in 2007 noted Pacific silver firs killed by silver fir beetles, and indicated stress caused by overstocking as a factor in the successful beetle attacks. Commercial thinning was suggested in order to improve tree vigor and reduce the risk of hemlock looper outbreak (Mehmel and Hadfield, 2007). Figure 1 shows the estimated area affected by forest pathogens in the Green Mountain Analysis Area based on Forest Health Aerial 8 of 23

9 Detection Survey data (USDA, 2016). Bear damage and root disease can have a similar appearance from the air and are reported together. Figure 1. Annual acres affected by forest pathogens in the Green Mountain Analysis Area. Palmer Drought Severity Index values (Figure 2) correlate well to recent levels of damage. Limited soil moisture increases the stresses on individual trees, making them less able to resist attack by insects or diseases. Severe and longer lasting drought events in 1993 and the 2000s coincide with hemlock looper outbreaks and increased hemlock dieback, bear damage and root disease, and fir engraver beetle damage, while years without drought have a much lower occurrence of damage. Looking at historical climate data it is clear that more severe droughts occurred in the period between 1920 and 1950, which predates the stands proposed for treatment. If droughts of such severity and intensity return, the risk of larger scale insect and disease outbreaks will increase. 9 of 23

10 Figure 2. Palmer Drought Severity Index from 1895 to 2016 for the Cascade Mountains West climate division (NOAA, 2016). Stand Structure These stands are in the stem exclusion stage of stand development (Oliver and Larson, 1996). Competition for growing space and resources (light, moisture, and soil nutrients) is high enough that some overstory trees are dying, and seedlings in the understory are unable to develop into mature trees. Relative density allows a quantifiable measure of stand density relative to biological thresholds for suppression mortality and maximum density, similar to stand density index. A relative density below 50 avoids suppression mortality and excessive restriction of crown development for coastal Douglas-fir, while 100 approximates its biological maximum density (Curtis, 1982). The stands proposed for commercial thinning have an average relative density over 80, indicating that trees are dying because density is too high, and individual tree growth is below potential. Restriction of crown development prevents tree branches from growing in length and diameter because they are crowded with branches from adjacent trees and receive limited light. While there are some benefits to restricting branch diameters for the purpose of high quality timber with fewer knots, the opposite applies for development of nesting platforms. Overcrowding in dense stands leads to suppression mortality, weakens trees, and decreases their resistance to damage by insects and disease (Oliver and Larson, 1996; Tappeiner, et al., 2007). Attributes of stands proposed for commercial thinning, as estimated from stand examination plots, are described in Table 2 and Table 3 below. Approximately 7% of the proposed stands are within the Silver Fir Zone. Table 2. Current average stand attributes by vegetation zone, for trees 6 inches DBH and greater. Vegetation Zone Total Acres Trees/ Acre Basal Area/Acre (sq. ft.) QMD Relative Density Canopy Closure (%) MBF/ Acre Western Hemlock Zone 6, Silver Fir Zone Table 3. Current average number of snags per acre by vegetation zone. Vegetation Zone Hard Snags per Acre DBH > 20 DBH Western Hemlock Zone Silver Fir Zone The snags created in this stage of development are limited to lower diameter classes, relatively short-lived, and not large enough to accommodate larger cavity-nesting species. Table 3 above summarizes the current average number of snags per acre by diameter class. As opportunities for natural disturbances that create canopy openings are limited, it may be several decades before existing seedlings in the stand have enough light to grow and contribute to a more complex canopy structure. 10 of 23

11 8. Environmental Effects (includes Cumulative) Analysis Area The analysis area for direct and indirect effects to forest vegetation is the extent of the stands proposed for treatment. Alternative 1 - No Action No direct effects would occur as a result of the No Action Alternative. The stands would continue to grow in dense conditions, causing additional suppression mortality (Oliver and Larson, 1996). This mortality would lead to a higher number of snags than if the stands were thinned, although they would mostly be from suppressed or intermediate crown classes and therefore relatively small and short-lived. Table 4 summarizes stand attributes by vegetation zone for the No Action Alternative after 50 years, for stands proposed for commercial thinning treatments. Quadratic mean diameter would be lower than if thinned, since tree growth rates would be below potential due to continued competition for growing space and resources, and small trees would not be removed. Given current stand ages and conditions another years could be needed for development of old growth structural characteristics. Crown width and branch diameter in dominant and co-dominant trees would be limited by competition for light between adjacent trees. Higher tree density could contribute to increased stress and higher height-diameter ratios, making trees more susceptible to breakage, windthrow, and attack by insects or disease. Table 4. Alternative 1 (No Action) Year 2066 stand attributes by vegetation zone. Vegetation Zone QMD Canopy Closure Hard Snags per Acre DBH DBH >30 DBH Western Hemlock Zone % Silver Fir Zone % Species composition would not change substantially in the near term unless natural disturbances cause species-specific mortality or create openings in the canopy that allow tree regeneration and increased understory vegetation, as canopy closure would remain high. Over several decades the shade-tolerant tree species would stay the same or increase in proportion, as openings in the canopy develop that release existing shade-tolerant seedlings and saplings from competition. Figures 3 and 4 below show expected changes in the number of large trees per acre in 50 years with no treatment, and tree species composition. 11 of 23

12 Figure 3. No Action Alternative large trees per acre. Figure 4. Current species composition. Climate Change Temperature for the Pacific Northwest is projected to increase 2.1 C by the 2040s and 3.8 C by the 2080s (Littell et al, 2011). Temperature is projected to increase in all seasons, but with the largest increases during the summer months. This seasonal difference would be a change in the trend observed in the 20 th century, which indicate more warming in the winter (Mote, 2003). Precipitation is projected to increase slightly, but the summer months are projected to have a 10% decrease in precipitation by the 2040s (Raymond et al, 2014). The effect of these changes on tree growth would depend largely on the degree to which decreased summer precipitation and higher temperatures contribute to drought stress. If soil moisture is more limited than present, increased stress may make trees less resistant to attack by insects and disease. For example, drought can limit the ability of Douglas-fir trees to produce enough sap to resist attack by Douglas-fir beetles, leading to tree mortality and increased risk of spread to adjacent trees. Increase in temperature alone may improve tree growth rates, especially at higher elevations where the growing season is shorter, but combined with limited precipitation during the growing season such changes are likely to cause a declines in tree growth (Restaino et al., 2016). Warming temperatures are likely to increase the frequency and severity of droughts, regardless of small changes in mean annual precipitation, leading to episodes of tree dieback or mortality, insect outbreaks, and fire (Peterson et al, 2014). The hemlock looper outbreak during the drought of and increased Douglas-fir beetle activity after the 2015 drought season may be indications of the types of events that may occur more frequently in the project area. Gradual shifts in tree species may occur in areas of marginal growing conditions, such as Pacific silver fir regeneration shifting upslope where temperatures remain cool enough for successful seedling establishment, and being replaced by western hemlock regeneration. The treeline is likely to shift upslope as growing conditions become more favorable at higher elevations of the Subalpine Fir Zone. Alternative 2 - Proposed Action The estimated acres of commercial thinning is less than the total stand acres, as portions of the stands would be within no-cut riparian buffers, inaccessible for timber harvest equipment, in hardwood patches, or otherwise unsuited for commercial thinning. Road reconstruction costs may also be prohibitively high in some areas, making it not economically viable to include 12 of 23

13 certain stands and associated access roads in a timber sale when the value of timber to be harvested is less than the costs of harvest. Based on recent timber sales on the Mt. Baker- Snoqualmie National Forest and project design, treated acreage is expected to be 30-50% of total stand area. Commercial thinning treatments would reduce relative density and produce timber used as raw material for the forest products industry in the Puget Sound region, in addition to economic contributions of job availability and associated labor income. The timber products program on the Mt. Baker-Snoqualmie National Forest is estimated to have contributed 280 jobs and $13.7 million in labor income to the local area in 2014 (USDA, 2016). Assuming 40% of total stand area is commercially thinned with an average yield of MBF/acre, approximately 97.5 million board feet of timber would be harvested in total, with an estimated net timber sale value of about $3.2 to $3.5 million and benefit/cost ratio of to at current weighted average delivered log prices (March 2017). Table 5 shows a range of possible net timber sale values, depending on percent of stand area harvested and log prices, which typically fluctuate seasonally and from year to year depending on market conditions, and both high and low road reconstruction cost estimates. At a lower percentage of stand acreage, for example if high stream density of yarding obstacles make a greater portion of stands inaccessible to harvesting, or if actual yield is lower due to marginal timber quality, some stands and associated road segments would not be economically viable. If less stand area is accessible for harvesting, delivered log prices decline, or costs increase, fewer of the stands proposed for commercial thinning would be economically viable because the high costs would lead to deficit timber sale or stewardship contracts. Highly deficit areas would need to be dropped from road reconstruction and timber harvest in order to maintain economic viability, leading to a reduction in timber volume in some scenarios. Similarly, the amount of pre-commercial thinning that could be completed would depend on how well suited the stand is for pre-commercial thinning operations as that affects thinning costs. High costs of pre-commercial thinning would allow fewer acres to be treated. Table 5. Estimated timber volume and net values under multiple scenarios, with high and low road cost estimates. Parentheses indicate negative values. *All Stands includes areas that are highly deficit, varying by scenario assumptions. Scenario Net Value Including All Stands* Est. Volume (MMBF) Net Timber Sale Value Benefit/Cost Ratio 40% acres, $562/MBF (current) $3,165,320 to $3,493, $3,165,320 to $3,493, to % acres, $512/MBF (down $50/MBF) ($119,214) to $251, $1,279,950 to $1,688, to % acres, $562/MBF $212,777 to 71.8 $53,019 to to (current) 30% acres, $512/MBF (down $50/MBF) $579,133 ($1,852,798) to ($2,250,624) $1,144, $162,348 to $462, to of 23

14 Road work and harvest activity associated with timber sales in the project could begin in 2018 and continue for approximately 10 years through successive timber sale contracts. Land clearing for recreation site improvements would produce merchantable timber which could be offered for sale, prior to or during construction of the improvements, or in conjunction with timber sales. Tables 6 and 7 summarize stand attributes by vegetation zone both post-treatment and after 50 years for the Proposed Action. Snag density would be reduced in thinned stands, as one of the effects of thinning is to reduce suppression mortality and improve the resistance of residual trees to attack by insects and disease (see Table 7). Height-diameter ratios are lowered by thinning, so although trees may be at higher risk of windthrow immediately after thinning, resistance is improved in the long term (Tappeiner, et al, 2007). As the stands proposed for treatment generally lack evidence of frequent windthrow, the short term increase in risk of windthrow may be minimal. Table 6. Post-thin average stand attributes by vegetation zone, for trees 6 inches DBH and greater. Vegetation Zone Total Acres Est. Thinning Acres* Trees/ Acre Basal Area/Acre (sq. ft.) QMD Relative Density Canopy Closure Yield MBF/ Acre Western Hemlock Zone 6,688 2, % 32.9 Silver Fir Zone % 48.3 *Assuming 40% of stand area commercially thinned. Table 7. Alternative 2 (Proposed Action) Year 2066 stand attributes by vegetation zone. Vegetation Zone QMD Canopy Closure Hard Snags per Acre DBH DBH >30 DBH Western Hemlock Zone % Silver Fir Zone % Canopy closure predicted by the FVS model for year 2066 (see Table 6) is likely underestimated, as tree regeneration that would contribute to canopy was not included in the model run due to unpredictability of natural regeneration and survival of existing seedlings after logging. Crown expansion with increased light availability also tends to increase canopy closure above model predictions within a few years after thinning. Portions of the commercially thinned stands would not be thinned because they are in no-cut riparian or wetland buffers, are in areas of sensitive or unstable soils, cannot be accessed by timber harvesting equipment, or are otherwise unsuitable for treatment. These skips are part of the project design, but no harvest activity would occur in them. Small skip areas would be used as needed to protect legacy features such as large snags and remnant old-growth trees from disturbance during harvesting. Such unthinned areas may help conserve mycorrhizal fungal mats by minimizing soil disturbance in the unthinned areas and allowing fungal recolonization as residual trees increase growth and carbohydrate flow to their root systems increases (Carey, 2003). 14 of 23

15 Commercial Thinning Thinning would primarily be from below, removing more trees in the smaller diameter classes and leaving trees 20 inches DBH or greater. The creation of gaps and heavy thin areas would contribute to spatial variability in tree density within stands. Figures 5 and 6 below show expected changes in the number of large trees per acre after 50 years and tree species composition post-treatment for commercially thinned stands. Figure 5. Alternative 2 large trees per acre (TPA). Figure 6. Alt. 2 post-thinning species composition. Diameter distribution of the Proposed Action will be improve desired characteristics for latesuccessional and riparian habitat, as there would be more trees in the largest diameter classes as a result of thinning. QMD in the Western Hemlock Zone would increase by about 5 inches over 50 years compared to the No Action Alternative (see Table 6). Western hemlock would make up less of a majority of the tree species, and representation of Douglas-fir, western redcedar, and hardwood species would increase, contributing to greater species diversity. Over time the proportion of western hemlock, western redcedar and Pacific silver fir would likely increase as existing understory trees develop into a second canopy layer and natural regeneration of these shade-tolerant species occurs. Gaps approximately ¼ to ½-acre in size would be located in 3 to 10% of the total stand area. All merchantable trees under 20 DBH would be harvested within gaps, except for minor species that are retained for species diversity. Within gaps canopy closure would be greatly reduced, possibly providing enough light for shade-intolerant trees species such as Douglas-fir and red alder to regenerate. The amount of light reaching the forest floor depends on the height of the surrounding tree canopy, aspect, and orientation of the opening relative to the angle of sunlight, so combined with the availability of seed from mature trees nearby the regeneration of shadeintolerant species is not entirely predictable. The small gap areas would provide limited patches of early-seral vegetation within the treatment stands. Heavy thin patches approximately ½ to 3 acres in size would be located in 3 to 10% of the total stand area. Immediately after thinning relative density and canopy closure would be reduced to the degree that even after tree crowns expand after thinning to capture more available light, small gaps in the canopy would allow light to reach the forest floor. This additional light would 15 of 23

16 benefit existing understory trees and increase abundance of understory vegetation. Large branches develop on widely spaced trees (Maguire, et al, 1991), so this treatment would increase the development of large branches and thus availability of nesting platforms for marbled murrelet in the future. Preference for retaining Douglas-fir as leave trees would create opportunities for epicormic branch development (new branch growth from dormant buds on the trunk) when additional light is available to the sides of the trees. Epicormic branches are an important habitat characteristic of old-growth forests and provide platforms that are important for wildlife and epiphytic plants. The additional light available to the forest floor after thinning would provide for increased understory vegetation and growth of tree seedlings to create a multi-layered canopy. If the increase in understory vegetation leads to an increase in use of the area by deer, natural regeneration of western redcedar may be limited by deer browse as cedar is typically preferred over other conifer species. The increase in understory vegetation would provide increased forage for herbivorous mammals, native pollinators, and songbirds (see Wildlife section). Variable density thinning treatments completed within the last 10 years on the Darrington Ranger District have shown a post-thinning increase in native understory plants with seeds that are distributed by wind or spread through bird activity, including fireweed, thimbleberry, salmonberry, huckleberries, trailing blackberry, and blackcap raspberry. Climate Change Under the scenario of increased temperature and decreased summer precipitation, the above treatments would increase resiliency of residual trees. By improving growing conditions, including reduced competition for soil moisture, trees would grow more vigorously and be less susceptible to mortality caused by insects or disease. Improved tree species diversity would develop greater resilience on a stand basis by diminishing the impact of species-specific insects or disease, such as Douglas-fir bark beetles or western hemlock looper, on the stand as a whole. The Proposed Action would implement an action item of the Vulnerability Assessment and Action Plan for National Forests in Western Washington, to maintain and enhance biodiversity and increase resilience (Aubry, et al, 2011). Action Item 2A of the Plan is to Continue the National Forests thinning programs. These programs achieve: 1) promotion of greater biodiversity by increasing the proportion of less abundant conifer and hardwood tree species, 2) the development of understory vegetation, 3) enhancement of the habitat value provided by forest stands, and 4) increased stand resistance and resilience to disturbance and environmental stressors. Additional information regarding the contributions of the proposed action on climate change is located in Appendix C, Climate Change. Alternative 2A The addition of new temporary road segments in Alternative 2A would improve or allow access to stand areas where existing non-system roads used in previous timber harvest would not be suitable. The additional temporary roads would likely maintain timber harvest within portions of proposed stands that would need to be dropped otherwise. The 9 commercial thinning stands or 16 of 23

17 portions of those stands dropped in Alternative 2A would reduce potential timber harvest by approximately 4.2 million board feet compared to Alternative 2; however because those stands are mostly over 80 years old, include extensive wetland areas, or are structurally not in need of silvicultural treatment to meet desired conditions, the actual reduction in timber volume at implementation is not likely to be substantially different than it would be in Alternative 2. The reduction in non-commercial thinning in Alternative 2A is similarly not likely to be different than it would be in Alternative 2, as the older non-commercial stands would likely be prohibitively costly to treat. Alternative 2B The addition of new temporary road segments in Alternative 2B would have the same impact on harvested stand area as Alternative 2A. Alternative 2B drops part of an additional stand, G59, from thinning treatments due to areas of root disease within that stand. Although areas of extensive mortality would be excluded from commercial thinning in all action alternatives, any remainder of the stand included in the area dropped that could be treated to increase residual tree health and resistance to bark beetles and hemlock looper, as recommended by several forest health specialists who conducted site evaluations (Mehmel and Hadfield, 2007; Dickinson, 2016). As the areas of stand G59 dropped in this alternative were not identified through stand diagnosis by a Silviculturist or in consultation with a forest health specialist, it is unclear what the actual change to treated acres would be. The reduction in non-commercial thinning in Alternative 2B is not likely to be different than it would be in Alternative 2, as those stands would likely be prohibitively costly to treat. The reallocation of 7 non-commercial stands to optional stands to add for potential thinning (meaning commercial thinning) is not associated with a valid basis for prescribing commercial thinning treatments or increasing the economic viability of commercial thinning in those stands, and as such those areas remain unlikely to be commercially thinned if this alternative is implemented. Considering this, the combined effect of the changes in Alternative 2B would reduce potential timber harvest by approximately 4.5 million board feet compared to Alternative 2, with the same caveats described above for Alternative 2A. Cumulative Effects The affected area for cumulative effects to the timber resource is the South Fork Stillaguamish watershed. Cumulative actions listed in Appendix C have been considered in the cumulative effects analysis for forest vegetation. Past and Present Actions Past timber harvest and development has reduced late-successional and old growth forest remaining in the watershed to approximately 60-80%. Much of the area is in mid-successional stages of stand development. Adjacent forested private lands have been managed with even-age silvicultural systems, creating large blocks of clearcut harvest and actively managed regeneration with preference for rapid growth of major commercial conifer species. Private lands within the National Forest boundary in the project area have been developed for residential and recreational use, leading to a loss of forested area including riparian areas along stream channels. 17 of 23

18 Future Actions Alternatives 2, 2A, and 2B would bridge stand development in treated stands from mid- to latesuccessional conditions sooner than Alternative 1 (No Action), and create small areas of earlysuccessional conditions through gap creation. Current forest management practices are expected to continue on adjacent private lands in the foreseeable future, maintaining a portion of the watershed in homogenous stands with limited species diversity that will not develop into late-successional forest. There is very limited possibility that activities on private lands within the project area could affect the timber resource within the project area, such as changing the seed source for trees that would grow through natural regeneration or increasing the likelihood of species-specific forest insect outbreaks by limiting tree species diversity or introducing invasive pests through human activities. Many invasive pest introductions occur through human vectors like recreational vehicle travel from infested areas and transportation of firewood containing invasive insects. The risk of windthrow may increase in stands adjacent to clearcut harvest; however, landform, wind direction, and soil characteristics are additional considerations in the probability of windthrow. Such effects would be greatly limited by distance and connectivity, and are largely dependent on other factors such as climate. The effects of the human activities listed above on the timber resource is overall likely to contribute to maintaining an available supply of timber within the South Fork Stillaguamish watershed, as active management sustains higher rates of timber growth over time compared to passive management. Forest cover would be maintained in varying age and structural classes. While diversity of structural classes is unlikely to change on private lands, the Proposed Action would lead to a greater range of structural characteristics within the watershed. 9. Forest Plan Consistency All Alternatives would meet Forest Plan Standards and Guidelines. However, Alternative 1, No Action, would forego opportunities for silvicultural treatments to better meet wildlife habitat objectives. Alternatives 2 and 2A would benefit the creation and maintenance of late-successional forest conditions, consistent with the Late-Successional Reserve Standard and Guideline in the Northwest Forest Plan ROD (p. C-12), and would control stocking, manage stands, and acquire desired vegetation characteristics needed to attain Aquatic Conservation Strategy objectives consistent with the Riparian Reserve Standard and Guideline (p. C-32). Alternative 1, No Action, would not control stocking or further development of late-successional forest conditions. Alternatives 2A and 2B would not differ substantially from Alternative 2 as stands that had not been identified as over 80 years of age or not well suited to pre-commercial thinning in Alternative 2 would not have been included in implementation of silvicultural treatments, which require stand diagnosis and silvicultural prescription prior to treatment, and large areas of wetlands or hardwoods in other dropped stands would have been excluded from thinning through design elements and mitigation measures. The inclusion of new temporary road segments in 18 of 23