Fire and Fuels Specialist Report - final

Transcription

1 United States Department of Agriculture Forest Service Rocky Mountain Region Fire and Fuels Specialist Report - final La Garita Hills Project Submitted by: Kent Smith, Fire/Fuels (Name ), (Resource) Paul Minow San Luis Valley Field Office (List any of the people that attributted to this report) 1

2 Contents Relevant Laws, Regulation, and Policy that Apply 3 Affected Environment (Existing and Desired Conditions) 4 Description of Alternatives 9 Direct and Indirect Effects 10 Cumulative Effects 15 Design Criteria 15 References 17 Appendix A - Methodology 18 Appendix B Maps 20 2

3 Scope of Analysis The analysis of the effects on fire and fuels includes the area within the LGH analysis area boundary. La Garita Hills Fire and Fuels Within the topic of fire and fuels, a distinction must be made between the terms fuels and hazard fuels. In the context of this document, fuels refers to any burnable, live or dead vegetation, within the analysis area. Hazard fuels and/or hazardous fuels refer to burnable, live or dead vegetation, which, if ignited, could threaten public safety, structures, or other improvements. Existing Conditions The existing fuels profile across the analysis area is quite diverse. Grass/shrub and piñon/juniper models are found in the elevation range. Mixed conifer, including the ponderosa pine, Douglas-fir, Douglas-fir mix, and bristle cone pine, range from ,500 in elevation. Aspen is found throughout the area, but primarily ranges from ,600 elevation. The spruce zone and spruce mix zone are found in the ,000 elevation range. Climate has a large impact on the fuels across the analysis area. Lower elevations receive approximately 8-10 inches of precipitation annually. Higher elevations receive approximately inches of precipitation annually, mostly in the form of snow. Average high temperature during, from May October, is 72.2 degrees (F), and the average low is 38.5 (observations taken at 7700 ). The dry, cool conditions provide a short growing season, which is not conducive to producing heavy loads of fine fuels, the primary carrier of fire. As such, accumulations of fuels across all fuel types and sizes are typically less than similar fuel types in other parts of the western United States. The La Garita Hills analysis area lies primarily in the Upper Rio Grande Basin of the state of Colorado Water Division III (Upper and Lower Rio Grande Basins). According to A History of DROUGHT IN COLORADO (No. 9 Second Edition, February 2000), The San Luis Valley in south-central Colorado is the driest region, averaging only seven inches in the center of the valley. 3

4 Within these generally cool, dry climate conditions there have been periods of wetter than normal and drier than normal precipitation. No clear cycle (or patterns) of these periods (short or long term) have been determined (A history of Drought in Colorado, No. 9 Second Edition, February 2000). When analyzing fuel types in reference to moisture regimes, wetter periods will typically stimulate growth in all vegetation classes, and produce more continuous fine fuels in the form of grasses and herbs. During drought conditions vegetation typically becomes stressed and is more susceptible to disturbances such as insects and fire. Fire Regimes A natural fire regime is a general classification of the role fire would play across a landscape in the absence of modern human mechanical intervention, but including the influence of aboriginal burning (Agee 1993, Brown 1995). Coarse scale definitions for natural (historical) fire regimes have been developed by Hardy et al. (2001) and Schmidt et al. (2002) and interpreted for fire and fuels management by Hann and Bunnell (2001). The five natural (historical) fire regimes are classified based on average number of years between fires (fire frequency) combined with the severity (amount of replacement) of the fire on the dominant overstory vegetation. These five regimes include: I 0-35 year frequency and low (surface fires most common) to mixed severity (less than 75% of the dominant overstory vegetation replaced); II 0-35 year frequency and high (stand replacement) severity (greater than 75% of the dominant overstory vegetation replaced); III year frequency and mixed severity (less than 75% of the dominant overstory vegetation replaced); IV year frequency and high (stand replacement) severity (greater than 75% of the dominant overstory vegetation replaced); V 200+ year frequency and high (stand replacement) severity. Fire regimes across the analysis area are variable according to the vegetation zone. The spruce and spruce mix zones are typically in fire regime IV and V. The aspen mix and Douglas-fir mixed conifer zones usually fall into fire regime III. Ponderosa pine stands are typically a fire regime I, but where there is a greater mix and density of other species with ponderosa, those areas are in fire regime III. A lack of fine surface fuels, and continuity of those fuels, reduces the number of ignitions and scale of fires in the piñon/juniper stands and they typically are in fire regime V. To help verify fire regimes, a cursory fire return interval (FRI) study was conducted in and around the analysis area. By sampling fire-scarred trees, the trees were aged and the interval between fires was calculated. A composite interval from each site was then established. A complete description of the methodology and analysis can be found in Appendix A. FRI was variable depending on site conditions. Lower elevation sites in ponderosa dominant stands had an average fire return interval of 30 years. Higher elevation sites in mixed conifer had an average fire return interval of 45 years. Average FRI prior to modern fire suppression intervention was 30 years in the lower elevation sites and 80 years in the higher elevation sites. Fire Load and Behavior The La Gartia Hills analysis area had 43 documented fires, from 1970 through 2012, with 56% 4

5 being natural ignitions. Seventy-two percent of fires have been 2.5 acres or less. Ninety-three percent of fires have been 40 acres or less. Only three larger fires have occurred: The Hellsgate Fire, 78 acres, in The Coolbroth Fire, 252 acres, in The Poison Fire, 306 acres, in While little is known about the Poison Fire, the majority of fire spread for both the Coolbroth and Hellsgate Fire occurred over one day. The Coolbroth and Hellsgate Fires are within a tenth of a mile of each other, on opposite sides of Carnero Canyon, and exhibited mixed severity fire behavior and effects. It s interesting to note that all three fires burned in the ponderosa pine and mixed conifer transition zones, at elevations between 8500 feet and 9900 feet, supporting a more frequent fire return interval at lower elevations (< 10,000 ) versus higher elevations where there is no record of large fires in recent history. The geography of the analysis area offers many natural fuel breaks in the form of rock outcrops, barren areas, drainages and riparian areas, which may inhibit fire spread. The lack of volume and continuity of fine surface fuels, due to soils, climatic conditions, and other land management actions, generally produces low intensity fire behavior. In areas with heavier fuel loading, higher fire intensities have been seen but these are often group torching or short duration runs, and are typically wind dependent. Fire control issues have been minimal, even during 90 th percentile weather conditions, with fires typically being contained within the first operational period. In 2005, the Benny s Creek and Buck Park 2 fires were allowed to burn with minimal management actions, based on favorable forecasted weather conditions, and were managed as Wildland Fire Use fires. These fires burned in fuel types similar to those in the La Garita Hills analysis area. Located four to five miles north-northwest of the analysis area, these fires started in July and burned for approximately six weeks with low to moderate intensities, and low to mixed severity. Some short duration runs occurred when low relative humidity and wind aligned, but the majority of fire behavior was smoldering and low intensity surface fire. With no containment or suppression actions taken on either fire, the Buck Park 2 fire reached 112 acres in size, and the Benny s Creek Fire reached 135 acres. Figure 1 shows fire behavior on the Buck Park 2 Fire. 5

6 Figure 1. Torching and smoldering in mixed conifer on the Buck Park 2 Fire. Insect and Disease Many insects and diseases are at work within the La Garita Hills analysis area. Some are recurring without huge effects to the landscape, some have been at epidemic levels and some remain at endemic levels. Spruce beetle infestations in the area have killed roughly 12,000 acres of spruce and spruce mix within the analysis area over the last five years, and have been at epidemic levels throughout most of the Rio Grande NF for over ten years. Western spruce budworm has remained at mostly endemic levels with major episodes every 9-12 years, as has been the case within the mixed conifer zone for hundreds of years. Mountain pine beetle are active and have had episodes of higher activity in the past 15 years, but are within the historic range of variability, compared to what has taken place in other parts of Colorado, in the last ten years. The effects of the spruce beetle infestation on fuels will take time. The vertical arrangement of the fuel will change as needles die and shed to the surface, and resulting snags eventually fall and become down, coarse woody debris. After dead stands lose their needles, surface vegetation such as grasses and herbs should increase with more sunlight and precipitation reaching the ground. This process could take decades to play out (DeRose & Long, 2009) Fire behavior within these beetle killed areas will be variable depending on the level of infestation and the stage and volume of mortality. A stand in the red needle stage may support crown fire under certain conditions, but it s doubtful it would be as volatile as a crown fire in a live stand. Dead stands that have lost their needles will most likely have a mixed severity fire depending on the amount of down, coarse woody debris and weather conditions. In areas where most of the snags have fallen, the heavy down, coarse woody debris fuel load could burn with higher intensity, but rate of spread will be dependent on the fine fuel loading (DeRose & Long, 2009). These higher intensities could impact soils in the form of sterilization and/or hydrophobicity. Wildland Urban Interface and Hazardous Fuels No existing data on structure or housing density in and around the analysis area was available. A visual assessment was conducted by the Forest Service using available public data sources. 6

7 Google Earth (imagery date, 2010) and National Agriculture Imagery Program (NAIP) photos (imagery date, 2009) of the analysis area were used. This assessment identified 87 sites of development in and around the area. An estimated 261 structures (e.g. houses, barns, out buildings, etc.) exist across these sites. Using the Silvis Laboratory, University of Wisconsin, definition of Wildland Urban Interface (WUI) as a guide, 48 sites roughly fit the Low Density Intermix (LDI) category. This category is described as having a structure density between 6.17 and structures per square kilometer, and the surrounding area being greater than 50% vegetated. Because some sites did not fall within the square kilometer criteria, their close proximity to the analysis area boundary and adjacent LDI sites that did meet the criteria, they were included. The LDI sites were mapped using GIS, and had a 1.5 mile buffer applied to the locations to represent the impact of potential spotting distance (Silvis Laboratory). This buffer, clipped to the analysis area, represents the WUI area in the analysis area. It is important to note that WUI areas only identify acres that could be impacted by a wildfire, burning under extreme fire weather conditions, and help fire and fuels management identify areas where fuel treatments and suppression efforts would be successful. There is no intent to treat all the acres within these areas. The La Garita Hills LDI is acres, comprising roughly 14% of the analysis area. Just over half of the LDI acres are vegetated with grass and piñon/juniper, the remaining LDI is in the timber litter, and timber understory fuel models. Local fuel load surveys in and around the analysis area typically record fine fuel loads less than half of those represented in fire behavior fuel models. These lighter fine fuel loads, the discontinuity of fuels, and the areas natural fuel breaks, most likely result in fewer fire starts, slower rates of spread, and limited growth potential under most conditions. Nevertheless, fires burning during very high and extreme fire weather indices can exhibit higher intensities and extreme behavior in fuels throughout the analysis area. The LDI structures identified lie within the North Saguache Fire Protection District and are covered under the County Wildfire Protection Plan. However, these areas are remote and have poor road access, increasing fire response times. Fuels Treatments Approximately 10,700 acres have been treated within the analysis area in the past twenty years, where fuels reduction was the primary objective. Those acres do not account for timber harvests and other vegetation treatments where fuels reduction was a secondary objective. The majority of fuels projects have been prescribed burns, with only 277 acres of mechanical treatment (chainsaw thinning prior to burning). Projects have been in ponderosa, Doug-fir Mix, and grass/shrub vegetation types, below 10,000 feet elevation. Primary prescribed burn objectives have been to reduce hazard fuels and return fire to the ecosystem, with a secondary objective of improving wildlife habitat. Desired Conditions The desired conditions differ for each vegetation zone and fire regime. For large portions of the ponderosa pine, Douglas-fir mixed conifer, and aspen vegetation zones, it is desired that the stands be fire-resilient. According to Forest Restoration and Fire: Principles in the Context of Place, from Brown et.al. (2004), A forest that is fire-resilient has characteristics that limit fire 7

8 intensity and increase the resistance of the forest to mortality. These characteristics are determined by the arrangement of fuels according to stand structure and species composition within those zones. The shade tolerant species composition and the dense structure of the spruce/fir and spruce mixed conifer zones are adapted to large-scale disturbances, such as insect outbreaks and stand replacing fire, and these characteristics are desired for those naturally functioning systems. General Desired Conditions by Vegetation Zone Aspen Mix Open stands with a diversity of age classes and few conifers in the understory. Healthy, aspen stands slow fire propagation and do not support crown fire, during most fire weather conditions. Douglas-fir/mixed conifer Stand structure should consist of multi-aged groups of trees, of varying size, with some interlocking crowns, and varied interspacing between groups. Stand species composition promotes Douglas-fir but accommodates other existing species. These types of stand structures should limit fire spread into the overstory under low to high fire weather conditions and limit the extent of active crown fire during high fire weather conditions. Grass Vigorous diverse plant communities that fill into barren areas and under open stands. These conditions would provide more continuous fine fuels that could carry fire into surrounding timber stands, helping return natural fire to the ecosystem. Fires under these conditions will affect a broader area, help naturally thin timber stands, and be more easily controlled. Piñon /juniper Stand structure consists of multi-aged groups of piñon /juniper, of varying size, with some interlocking crowns, and varied interspacing between the groups. These stands would be resistant to independent and active crown fire, during low to high fire weather conditions, due to interspaced grouping and lack of herbaceous fuel under the stands. Ponderosa pine Stand structure is variable but generally uneven-aged and open; occasional patches of even-aged structure are present. The forest arrangement is in small clumps and groups of trees interspersed within variably sized openings of grass/forb/shrub vegetation associations similar to historic patterns. Size, shape, number of trees per group, and number of groups per area are variable across the landscape. Composition of these stands is ponderosa pine dominated with some mixed conifer and aspen. Fires in these stands would typically be low severity surface fires that maintain stand structure by killing young understory trees, maintaining openings and reducing competition among existing trees. Riparian Composition consists of a mosaic of shrub and herbaceous-dominated communities, with only minor conifer encroachment. Under most conditions, these areas would stop or slow wildfire propagation. Shrub Shrub dominated structures of varying sized groups within interspersed openings. Fires in these areas would have little effect on shrubs, and shrubs typically burn with low to moderate intensity. 8

9 Spruce Fir Stand structure consists of large expanses of multi aged groups as well as single aged stands, with small interspaced openings. Large subalpine meadows exist in areas where soil types do not support conifer growth. Canopies are typically low and uniform throughout the stands. Under low to moderate fire weather conditions, fires are very small and only effect small portions of stands. Stand replacing fire is more common when high to extreme fire weather conditions exist, allowing fire to propagate into the canopies, and affect stands at the landscape scale. Spruce Mixed Conifer - Stand structure consists of large expanses of multi aged groups with a minor component of single aged stands, with varying interspaced openings. Large subalpine meadows exist in areas where soil types do not support conifer growth. Species mix will vary based on aspect, elevation, and previous disturbances. Depending on the type and arrangement of species present canopy structure may be more open and less dense. Under low to moderate fire weather conditions, fires are very small and only effect small portions of stands. During high to extreme fire weather conditions fires will tend to be mixed severity with potential for stand replacement when spruce is the more dominant species. Description of Alternatives Alternative 1 - No Action Please refer to Chapter 2 for full description of alternatives. Alternative 2 Please refer to Chapter 2 for full description of alternatives. Alternative 3 Please refer to Chapter 2 for full description of alternatives. Alternative 4 Please refer to Chapter 2 for full description of alternatives. Direct and Indirect Effects To assess the effects of each alternative, in regards to fuels, a common metric needed to be established. On a landscape scale, Crowning Index can be used to quantify fuels characteristics and were used in this analysis. The Crowning Index (CI) is the 6.1-m (20 foot) windspeed at which active crowning is possible, based on Rothermel s (1991a) crown fire spread rate model and Van Wagner s (1977) criterion for active crown fire spread. CI is a function of canopy bulk density, slope steepness and surface fuel moisture content USDA Forest Service Research Paper RMRS-RP-29. (2001). The higher the 20 wind speed, the more resistant a stand will be to active crown fire activity. To assess CI in this analysis, common stand exam data collected within the analysis area, between 1980 and 2013, were uploaded to the Field Sampled Vegetation (FSVeg) database. These data were then imputed across the analysis area using the FSVeg Spatial Data Analyzer, to represent current conditions. These data were then modeled using the Forest Vegetation Simulator (FVS), to show the effects of the action alternatives, which includes CI. Using the 9

10 mean crowning index metric for each vegetation zone, the effects of the treatments could be compared over a fifty-year period. Alternative 1 (NO ACTION) Under the no action alternative, current processes will progress relying only on natural disturbances to alter stand structure, composition, and size. No salvage harvests, mechanical thinning or manipulation, or prescribed burning would take place. Wildfires will be managed to protect values at risk and/or resource benefit, where allowed. In general, stand densities, fuel loads and fuel continuity will increase, increasing the potential for a larger scale, moderate to high severity wildfire, in most vegetation zones. There will be no direct effects of the no action alternative. The indirect effects of the no action alternative per each vegetation zone are as follows: Aspen mix Mature aspen stands will become decadent, with little chance for rejuvenation, due to lack of disturbance. Early and mid-seral aspen stands will continue to be overtaken by conifer encroachment and eventually be replaced by conifers. Aspen stands with moderate to high rates of conifer encroachment will be less resistant to wildfire. Douglas-fir mixed conifer Stands will continue to be affected by western spruce budworm and dwarf mistletoe. Competition for moisture within dense stands will continue to stress all species making them more susceptible to disease and insects, such as Douglas-fir beetle and mountain pine beetle, which are currently effecting stands at endemic levels. Fuel loads will continue to increase incrementally over time, increasing the risk of mixed to high severity wildfire at scales out of the range of natural variability. Grass Meadow and grassland productivity will continue to be driven by climate, range management practices and natural disturbance (wildfire). Wildfire has been an infrequent disturbance in these areas, due to the non-continuous and sparse fuel load, and will likely have little impact in the future. Piñon/juniper These stands will continue to encroach into interspaced openings. Crown continuity in denser stands will support independent crown fire in extreme fire weather conditions. The lack of herbaceous surface fuels will inhibit wildfire ignitions, and fires that do start will most likely effect stand structure on a very small-scale under low to high fire weather conditions. Ponderosa Stand composition and structure will change over time. Interspaced openings within the ponderosa pine will gradually be encroached by a mix of species. Understory species will increase in numbers and act as ladder fuels to the overstory. As these changes occur, wildfires will most likely be of mixed to high severity during high to extreme fire weather conditions. Riparian Structure and composition of riparian areas will change over time, as conifer continues to encroach into these areas. This encroachment could lead to an increase in crown fire potential and higher severity fire during extreme fire weather conditions. Shrub Shrubs will likely be unable to compete with other species as conifer encroaches into interspersed openings between timber stands. Fire will have little effect on shrubs during low to moderate fire weather conditions due to lack of herbaceous and surface litter fuels. 10

11 Spruce/fir - The short-term effects of the spruce beetle mortality will be an increased risk of crown fire initiation and spread while the dead trees retain the red or gray needles. Dead needles drop from the trees within one to three years, drastically reducing the torching and crowning potential. An increase of surface litter fuels will result, along with an increase in herbaceous fuels as more sunlight and precipitation are allowed to reach the forest floor. The increase in available fine fuel, along with the opening of the canopy, will allow for stronger winds at ground level resulting in potentially higher rates of spread for surface fires. While the risk of crown fires decreases, the rate of spread for surface fires will increase. As regeneration grows and fills in gaps, the potential for higher rates of spread would decrease as stand composition and structure slowly returns to a closed canopy. Over the long term, as more of the dead trees fall, coarse woody fuel loading of large diameter material would increase and result in hotter fires with longer residence times. These high intensity burns could increase soil heating at greater depths, detrimentally affecting soil microorganisms and nutrient cycling. Spruce/mixed conifer Stand structure and composition will vary depending on the amount of spruce present and be largely dependent on aspect, however the indirect effects will be very similar to those in the spruce/fir. Figure 2 shows crowning index of the current conditions, in 2014, and the subsequent spruce mortality due to spruce beetles in As a result, there was an increase in CI in the spruce/fir, spruce mixed conifer, and aspen mix zones. From 2024 on, CI values remain at a relatively steady state over the next 30 years. 20' Wind Speed - mph Figure 2. Alternative 1 (NO ACTION) - Crowning Index Aspen mix Douglas-fir/mixed conifer Piñon/Juniper Ponderosa pine Spruce/Fir Spruce/mixed conifer 11

12 Alternative 2 The effects of the Alternative 2 actions will be addressed by activity type: Salvage/sanitation salvage/intermediate harvests o Direct effects - These activities will reduce the amount of live and dead fuels (trees) in those areas. In spruce mix areas, the removal of dead boles will decrease the number of snags that would eventually fall, becoming coarse woody debris. There would also be a reduction in canopy continuity and canopy bulk density, providing openings for moisture and sunlight to reach the forest floor. There will be an increase in surface activity fuels from timber harvest activities, but this could be mitigated by the piling and burning of those fuels. o Indirect effects By reducing the amount of live and dead trees, with corresponding reduction in canopy bulk density and continuity, the potential for torching and crowning is reduced. Removal of spruce snags will also reduce the amount of dead boles that would eventually fall and become large coarse woody debris, thus reducing the potential for high severity fire and detrimental soil heating. Timber Stand Improvement (TSI)/TSI with Prescribed Fire o Direct effects These activities will primarily reduce the amount of live and dead fuels (trees) in the small diameter class (, 8 dbh) through felling or mastication. This would result in a reduction in canopy continuity and canopy bulk density while retaining the mature characteristics of the stand. These treatments will also be designed to provide interspersed spacing between groups of trees. Surface activity fuels would increase with these activities, but will be used to help propagate fire during prescribed burning treatments. Prescribed fire would remove some natural fuels as well as thin immature trees that would not be treated as part of the TSI prescriptions. In WUI areas thinning and/or masticating will be designing to break up canopy continuity and bulk density, providing aerial fuel breaks to reduce the extent of potential crown fire. o Indirect effects - By reducing the amount of live and dead trees, with corresponding reduction in canopy bulk density and continuity, the potential for torching and crowning is reduced. Altering stand structure through these treatments would remove ladder fuels, and create openings, while retaining older more mature trees that are more resistant to fire and in turn reducing the potential for torching and crowning. These treatments would create openings, reduce competition for moisture and provide more precipitation and sunlight to reach the forest floor, promoting shrub and herbaceous response. Prescribed fire o Direct effects Prescribed fire will reduce the natural fuel loads and alter stand structure to some extent. In areas prescribed for under burning, woody debris, surface litter, and seedlings and smaller trees will be reduced while canopy base height is increased. In areas prescribed for mixed severity burning, fire behavior that alters stand structure will be desired so that larger groups of trees are affected to create openings and reduce overall stand density. 12

13 o Indirect effects By reducing natural fuel loads and altering stand structure, the ecosystem will be more resilient to future fires, droughts, and disease and insect outbreaks. In Figure 3, current conditions are represented in the year 2014, followed by the spruce mortality in the spruce/fir, spruce mixed conifer, and aspen mix zones, and proposed treatments occurring in the year 2015, and the subsequent effects through the year Figure 3. 20' Wind Speed - mph Alternative 2 - Crowning Index Aspen mix Douglas-fir/mixed conifer Piñon/Juniper Ponderosa pine Spruce/Fir Spruce/mixed conifer CI is nearly doubled in each vegetation type, after treatments in 2015, and gradually decreases over time as crown bulk densities increase as stands mature. However, this decrease in CI does not reach current levels, even after fifty years. Fire adapted types, aspen mix, ponderosa pine, and piñon/juniper, show the strongest long term response as these species do well in open stands and tend to self-prune as they mature. Non-fire adapted types, spruce/fir, spruce mixed conifer, and Douglas-fir mixed conifer show a strong initial response followed by a larger decrease in CI as they are typically shade tolerant species that produce understory more rapidly. The proposed action treatments will all alter stand structure, composition, and fuel loading to some extent that will effect CI and create more fire resilient stands. In some instances, more than one treatment may need to occur in a specific area to achieve desired results. The adaptive management approach will allow for flexibility in treatment options as monitoring reveals whether treated areas are moving towards desired conditions. 13

14 Alternative 3 The areas identified for treatment in Alternative 3 are smaller, yet yield similar effects as Alternative 2, as shown in Figure 4. Figure 4. 20' Wind Speed - mph Alternative 3 - Crowing Index Aspen mix Douglas-fir/mixed conifer Piñon/Juniper Ponderosa pine Spruce/Fir Spruce/mixed conifer Alternative 4 The areas identified for treatment in Alternative 4 are smaller, yet yield similar effects as Alternative 2, as shown in Figure 5. Figure 5. 20' WindSpeed - mph Alternative 4 - Crowning Index Aspen mix Douglas-fir/mixed conifer Piñon/Juniper Ponderosa pine Spruce/Fir Spruce/mixed conifer Cumulative Effects Common to all Alternatives Past Actions Fuels reduction treatments have occurred in the project area over the last twenty years, resulting in 10, 700 acres treated with prescribed fire and 277 acres treated (thinned) mechanically. These 14

15 treatments primarily occurred in ponderosa pine, returning fire to the ecosystem, acting as maintenance burns. In all action alternatives the use of prescribed fire and mechanical thinning would continue, with Alternative 2 affecting up to 121,500 acres, Alternative 3 affecting roughly 89,000 acres, and Alternative 4 affecting roughly 83,000 acres. On-going present Actions Currently there are no fuel reduction projects planned in the analysis area, other than what is being proposed by this EIS. Future Actions Under all action alternatives, the use of best management practices will be employed as defined in the design criteria for this project, and negative impacts are expected to be minimal. As the forested stands and grasslands respond to the treatments, and vegetation becomes established and/or recovers, the negative effects will fade and the forest condition will return to a natural functioning state. Crowning Index will increase in treated areas and will mostly remain higher than current values over the time span modeled. Design Criteria Prescribed Fire o Prescribed fire plans will be prepared in accordance with the November 2013 Interagency Prescribed Fire and Implementation Procedures Guide, and be reviewed and approved by all required personnel. o Silvicultural prescriptions will be utilized to prepare and write fire behavior prescriptions for each burn plan that address species and size class specific mortality constraints. o Fire behavior prescriptions should be designed to mitigate effects of prescribed fire on coarse woody debris to meet forest plan and/or wildlife standards. o Natural features and existing roads and trails will be used as containment lines where appropriate in order to minimize the need to construct hand lines. Air Quality o Prescribed burning operations will comply with the State of Colorado air quality regulations. A State of Colorado smoke permit will be obtained for each prescribed fire treatment that lists the limitations and stipulations specific to each treatment and site. Monitoring Prescribed Fire o Vegetation and fuel load monitoring will occur, as needed, to assess pre and post fire effects. o Fuels and weather conditions will be monitored as described in each prescribed fire plan. o Fire behavior will be monitored throughout burning operations. Air Quality o Smoke impacts will be monitored throughout burn operations. 15

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17 References Agee, J.K Fire ecology of Pacific Northwest Forests. Island Press, Wash. DC. Brown, J.K Fire regimes and their relevance to ecosystem management. Pages In Proceedings of Society of American Foresters National Convention, Sept , 1994, Anchorage, AK. Society of American Foresters, Wash. DC. Hann, W.J., Bunnell, D.L Fire and land management planning and implementation across multiple scales. Int. J. Wildland Fire. 10: Hardy, C.C., Schmidt, K.M., Menakis, J.M., Samson, N.R Spatial data for national fire planning and fuel management. International Journal of Wildland Fire 10: Schmidt, K.M., Menakis, J.P. Hardy, C.C., Hann, W.J., Bunnell, D.L Development of coarse-scale spatial data for wildland fire and fuel management. General Technical Report, RMRS-GTR-87, U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fort Collins, CO. 17

18 Appendix A - Methodology Fire Return Interval Study To help determine the accuracy of the FRCC data, a cursory fire return interval (FRI) study was conducted on five sites in and around the analysis area. Tree data was recorded by hand and locations were logged using a GPS and mapped using ArcMap. The study sampled fire scarred trees using two methods; tree cores were obtained using increment borers, and chainsaws were used to fell trees and cut slabs containing fire scars from them. The increment borer method proved to be ineffective in accurately determining FRI, however the slab method provided quality data. Slab samples were planed and incrementally sanded smooth. Using a dissecting microscope, and other magnification equipment, tree rings were then counted to determine date and age of the tree and years between fire scars. In cases where dead trees were sampled, age and years between fire scars could only be determined. Tree rings in most of the samples were extremely dense, making counting accuracy difficult. Once all samples from each site were counted, data were recorded in FHX2 Software for Analyzing Temporal and Spatial Patterns in Fire Regimes from Tree Rings (Grissino-Mayer, ). The data were then graphed using Fire History Analysis and Exploration System (FHAES) software to develop the composite interval of the site. The Sheep Creek site is displayed below. Taking counting inaccuracy into account, scars that were clustered in the same time span were most likely scared by a single fire event. For example, using the graph above, the four scars that are clustered near the year 1900 were most likely scared during the same fire. By using this inference the average fire return interval for each site was calculated. Wildland Urban Interface (WUI) Low Density Intermix (LDI) There were no existing structure data readily available for the La Garita Hills Analysis Area. 18

19 Using Google Earth (2010) and GIS orthographic photos (2009), a visual assessment of private land in and around the analysis area was conducted. When a structure or group of structures was identified they were added to a GIS layer as a structure site. In all cases there was at least one structure at a site, and in most others there were multiple structures at a site (not every structure was individually counted). Eighty-seven sites were identified. Due to the variation in number of structures at each site, the number of sites (87) was multiplied by three, to get an estimate of the number of total structures (261). These structures include houses, garages, barns, sheds, and other out buildings. These data was then assessed for structure density. The Silvis Lab, University of Wisconsin is a WUI research organization. Silvis Lab definitions of WUI are used by the Forest Service, Fire Program Analysis (FPA). We utilized the Silvis Lab WUI definitions as a guide for defining the La Garita Hills WUI areas. The Silvis Lab s definition of LDI represents areas with housing density >= and <= , Vegetation >50%, in a square kilometer. Using a square kilometer grid overlay in ArcMap, the structure site density was visually assessed to see which sites roughly met the LDI definition. Those that did were added to a LDI structure layer. In some cases structures that did not meet LDI criteria were included due to their location between the analysis area boundary and nearby, true LDI structures. This judgment was based on a hypothetical response to a fire burning on federal lands towards private property and those structures being the first needing defense. The LDI sites were mapped using ArcMap, and had a 1.5 mile buffer applied to the locations to represent the impact of potential spotting distance (Silvis Laboratory). This buffer, when clipped to the analysis area, represents the amount of WUI within the La Garita Hills analysis area (25,903 acres). 19

20 Appendix B Maps 20

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