Main | Table of Contents | Executive Summary | Letter from the Superintendent | Abstract | List of Tables | List of Maps | Appendices
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Main | Table of Contents | Executive Summary | Letter from the Superintendent | Abstract | List of Tables | List of Maps | Appendices |
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Purpose and Need | Alternatives | Affected Environment | Environmental Consequences | Wild and Scenic Rivers | Consultation and Coordination | List of Preparers |
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CHAPTER TWO ALTERNATIVES (Including the Preferred alternative) [click here for a menu of this chapter] IntroductionThis chapter describes the three action alternatives selected for analysis for the Draft Yosemite Fire Management Plan/Environmental Impact Statement (EIS). It also describes the no-action alternative that represents the existing fire management program. Each of the three action alternatives presents a separate comprehensive proposal for the restoration of fire to park ecosystems and the management of hazardous levels of vegetative fuels. Each alternative proposes to use prescribed and managed wildland fire throughout the park, as well as mechanical methods to reduce forest fuels in developed areas. Alternatives differ in the time and methods used to accomplish restoration and fuel reduction. A detailed description of the effects on the environment of each alternative follows in Chapter 4, Environmental Consequences. The no action alternative required by the National Environmental Policy Act (NEPA) would continue the current fire management program. This program includes hand cutting, prescribed fire, managed wildland fire, and suppression strategies. It has been in effect since roughly 1970, but has been meeting neither the park’s land management objectives, nor the needs of the park’s neighbors. Since the program began, the park has reduced fuel buildup and begun to restore natural fire regimes in some areas, but not at the rate needed for comprehensive ecosystem maintenance and restoration. In addition, the current program does not satisfy the new requirements of the National Fire Plan and the 2001 Federal Fire Policy. The action alternatives (Alternatives B, C, and D) propose methods by which to meet the ecosystem maintenance and restoration and hazardous fuel reduction goals of the Yosemite Fire Management Plan. These methods would meet the long-term goals of Yosemite’s General Management Plan, Resources Management Plan, and Vegetation Management Plan, as well as fulfill the requirements of the National Fire Plan and Federal Fire Policy. Process for Formulating the AlternativesThe Yosemite Fire Management Plan was last revised in February 1990. Yosemite National Park has long recognized that fire management, as a program, should evolve as results from research and monitoring reveal new information about fire ecology, fire behavior, and fuels management. Scientific knowledge and experience has been critical in developing practical, feasible alternative methods to manage fire in the park. In addition, participation from the public and federal, state, and local agencies is an important component in planning processes in Yosemite. The action alternatives considered in the Draft Yosemite Fire Management Plan/EIS were developed from comments and concerns expressed by the public; input from federal, state, and local agencies; guidance from existing park plans; policy guidance from the National Park Service, and the National Fire Plan, and Federal Fire Policy; and research, monitoring, and experience from the existing fire management program and the U.S. Geological Survey Biological Research Division, Yosemite Field Station. The 2001 Federal Fire Policy emphasizes the use of prescribed and wildland fire to meet land management goals, restore ecosystems, and assure public and firefighter safety. The National Fire Plan calls for increases in fuel reduction to protect the wildland/urban interface (communities, developed areas, structures, and utilities) from fire. It also calls for increases in the number of firefighters and the amount of firefighting equipment to allow fuel reduction work to continue during elevated firefighting activity in other parts of the state or country. These guiding principles provided direction as the alternatives in the Draft Yosemite Fire Management Plan/EIS were developed. Members of the public; federal, state, and local agencies; and the National Park Service identified important issues during two periods of public scoping. Preliminary scoping took place in early 1999. In March and April of 2001, an additional scoping period was announced with the Notice of Intent to prepare an EIS on the Yosemite Fire Management Plan. Scoping comments focused on air and water quality, mechanical fuel reduction, wilderness, sensitive species, and other matters. The issues identified during public scoping are summarized as concern statements in Chapter 1 (page 1-21). The Yosemite fire management staff used the issues first identified in 1999 to begin consultations with fire and resource management specialists in Yosemite and in other fire and land management agencies to develop goals and objectives and to evaluate potential fire management activities. Concepts for developing a range of alternatives began taking shape in December of 2000, following consultations with the park’s Resource Management Division. It was suggested that the alternatives vary in two ways: ¨ By the various combinations of wildland fire, prescribed burning, fuels treatments, and fire suppression considered in the program, and ¨ By the amount of time needed to reduce fuels in developed areas and restore or maintain the natural fire regime throughout most of the park.
Finally, the comments received during the March and April 2001 scoping period were used to further develop the range of alternatives and identify needed analyses. The appropriate type, amount, location, and boundaries of proposed fire management activities were based on the identification of existing conditions, departures from the natural fire return interval, and target conditions (see Ecological Basis for the Alternatives, below). In addition, because program development based on sound science and practical experience is vital to Yosemite’s fire management program, adaptive management became a component of each alternative. The proposed fuel reduction and fire activities were evaluated as to whether they were reasonable and/or feasible. Some actions were considered and dismissed from detailed study. The Council on Environmental Quality regulations state that only a reasonable number of examples covering the full spectrum of alternatives must be analyzed and compared [40 CFR Parts 1500-1508 (1987)]. National Park Service staff used the project goals and objectives, policies and planning guidance, and public concerns to combine individual actions and thus fully develop the three action alternative concepts that were carried out into detailed analysis. Once the alternative concepts had been developed, they were more fully evaluated within the framework of meeting or, as appropriate, balancing the criteria outlined below. The evaluation of the alternative concepts also determined whether they would need to be modified to meet the broad goals of the General Management Plan, Resources Management Plan, Vegetation Management Plan, and Merced Wild and Scenic River Comprehensive Management Plan, as well as the specific purpose and need of the Yosemite Fire Management Plan. Alternatives were also examined as to how well they adhered to the laws and regulations pertaining to special land designations, in particular the Wilderness Act, the Wild and Scenic Rivers Act, and the California Wilderness Act of 1984 which established Yosemite’s designated wilderness and the Tuolumne Wild and Scenic River. The environmental consequences of implementation were identified by the planning team and other park staff members. Following administrative review, the proposed alternatives were modified and refined, and suggestions were made as to how analysis of environmental consequences could be modified to better address effects of changes on park resources and other fire management issues including wildland/urban interface protection. The preferred alternative was chosen after evaluating each alternative based on: (1) how well it achieved the purpose of and need for the Yosemite Fire Management Plan; (2) how well it achieved the goals of the General Management Plan, Resources Management Plan, and Yosemite Vegetation Management Plan; and, (3) how well it addressed issues and concerns expressed by the public. The planning team recommended Alternative D as the preferred alternative in the Draft Yosemite Fire Management Plan /EIS. CriteriaNational Park Service staff used the project goals and objectives described in Chapter 1 (Goals and Objectives of the Yosemite Fire Management Plan), policies and planning guidance, and public concerns to fully develop the three action alternative concepts that were carried into detailed analysis. In addition, the alternative concepts were examined again to verify that they satisfy a set of criteria based on the goals and objectives, other plans in effect in Yosemite, Federal Fire Policy, and the many acts, laws, and regulations under which Yosemite National Park operates. These criteria thus are based on the responsibilities Yosemite National Park is entrusted to follow. For the Yosemite Fire Management Plan the criteria are: ¨ Restore or maintain natural fire regimes. · Actions should move toward restoration of the natural fire regime in areas of the park where natural or prescribed fire is an acceptable method of vegetation management. · Actions should move toward restoration and maintenance of the natural range of variability for plant community structure and fuel loads. ¨ Focus on ecosystem processes. · Actions should allow natural processes to prevail where they do not threaten structures or protected areas (such as wildland/urban interface areas). · Actions should further ecosystem restoration so that, in the future, fire processes may be used to help sustain or maintain the park’s ecosystems. ¨ Protect and maintain cultural landscapes and historic and prehistoric resources. · Actions should help maintain and protect cultural landscapes and landscape features. · Actions should maintain light (within natural range of variability) surface fuels on and adjacent to archaeological sites and historic structures. · Actions should protect cultural resources, to the extent feasible, from the damaging effects of fire and fire management actions. · Actions should sustain traditional cultural resources (plants, occupation sites) where traditional activities such as plant gathering are important. ¨ Manage consistent with other land use designations within Yosemite National Park. · Actions should support wilderness characteristics. · Actions should protect and enhance Outstandingly Remarkable Values (ORVs) within the boundaries of Wild and Scenic Rivers and protect ORVs outside the boundaries. In the case of the Tuolumne Wild and Scenic River, values for which the river was designated should not be degraded. ¨ Establish and manage Special Management Areas to accomplish area specific goals. · Actions should protect and provide for the special management needs found in: § Giant sequoia groves § Wildland/urban interface areas § Boundary areas · Actions should reduce fuel accumulations in wildland/urban interface areas. · Actions should move toward reducing the risk of high-intensity wildland fire and restore natural and cultural resource conditions by restoring natural plant community structure and fuel loads in areas adjacent to Special Management Areas. Ecological Basis for the AlternativesInformation on fire history and fire ecology was used to assess the current ecological condition of plant communities in the park and develop a set of target conditions for vegetation and fuels. The assessment of existing conditions was based on departure from the natural fire return interval as described below. Target conditions were developed in conjunction with fire specialists at Sequoia and Kings Canyon National Parks (table 2.3). Existing and target conditions were used to determine the appropriate type, amount, and location of fire management activities and the boundaries of fire management units in the action alternatives in this plan. Fire Return Interval Departure (FRID)A fire return interval is defined as the number of years between naturally occurring fires at a specific location that is representative of a typical stand of that vegetation. For example, a fire scar analysis of a sample of trees in a stand of ponderosa pine trees might show that natural fire has occurred in that stand from as frequently as every two years (minimum value) to as infrequently as every six years (maximum value). The median value for the stand would be four years. The fire return interval for a given vegetation type can be used in conjunction with fire history maps to determine where naturally occurring fires have missed an area and the number of years between successive naturally occurring fires in an area. This information is known as the fire return interval departure (FRID). For example, if fires were suppressed in the above-mentioned stand of ponderosa pine trees for 60 years, the stand would have missed 30 fires based on the minimum fire return interval of 2 years, 15 fires based on the median interval of 4 years, and 10 fires based on the maximum interval of 6 years. Vegetation communities can change on a landscape scale when areas have not been allowed to burn at natural intervals. A geographic information system (GIS) based analysis was used to assess landscape scale change in the ecological condition of vegetation communities in Yosemite. This analysis, originally developed in Sequoia and Kings Canyon National Parks (Caprio and Lineback 1997), uses deviations from the natural fire return interval as an indicator of change in natural conditions (van Wagtendonk et al. 2002). In general, the further vegetation communities depart from their natural fire regimes, the more unnatural conditions prevail and the higher the risk of a stand replacement wildland fire, which is not natural to forests with surface burning fire regimes. Maximum fire return interval departure (FRIDmax) represents the most conservative estimate of how severe the deviation from natural conditions might be in terms of fuels and vegetation. Median fire return interval departure (FRIDmed )gives a moremoderate view, while the minimum fire return interval departure (FRIDmin) presents the most extreme indication of how far the stand is from its natural condition. This Draft Yosemite Fire Management Plan/EIS presents a range of fuel reduction target acreages based on the median and maximum fire return interval departures. The first step in the analysis was to group the park vegetation types into fire vegetation types that are based on similar fuels and fire behavior (Appendix 10 and map 2-1). The second step was to assign median and maximum fire return intervals to fire vegetation types (map 2-2). The third step was to use fire scar, fire history, and stand structure studies conducted in the Sierra Nevada to create a map of when each acre of the park had last burned (map 2-3). Fire history maps date back to 1930 for the park and from these we can derive 80 years of fire history for the park. In addition, it is known that by the 1860s fire suppression as well as logging was going on in places that are now part of Yosemite National Park. Fire history records date to 1958 for the El Portal Administrative Site, and again we know that settlement impact was influencing the fire regime much earlier. The final step was to calculate departures from the natural fire interval and create maps that depict the number of interval departures for both the median (map 2-4) and maximum (map 2-5) fire return interval departures. This is done using the following map algebra: FRID = |Fire Return Interval – (Current Year – Year Last Burned)| Fire Return Interval
As of the year 2000, results of the median FRID analysis indicate that 62% of park vegetation is considered to be in acceptable ecological condition (i.e., little to no deviation from natural fire regime), (table 2.1). These areas are expected to remain in acceptable ecological condition as long as the natural fire regime is maintained. Another 13% of the park vegetation shows significant deviation from natural conditions and 25% of the park is considered highly compromised by past fire suppression. In the El Portal Administrative Site, 38% of the area is considered to be in an acceptable condition, 43% shows significant deviation from natural conditions, and 19% is highly compromised—showing high departure from the natural range of variability (table 2.2). It should be noted that much of the area that shows significant deviation from natural conditions is in the western portion of the park, in lower elevation forests where fires have been suppressed either because of the presence of nearby communities or park boundaries. This area includes the giant sequoia groves. Despite ongoing reintroduction of fire to the groves over the past 30 years, progress has been slow—17% of the groves still contain unnaturally high levels of fuel. The analysis does show positive effects from fire management activities, as many areas are in an acceptable condition, but also underscores the fact that large areas require attention. In the action alternatives, fires would continue
to be suppressed in this area due to safety constraints. The area would be managed to restore ecosystems while
reducing risk of unwanted fire. This
would be done through prescribed fire throughout the Suppression Unit
and fuel reduction in the wildland/urban interface, along road and
utility corridors, and in other areas with resources needing
protection from fire.
Table 2.2 Fire Return Interval Departures by Percentage of Vegetation Type for Median Fire Return Intervals at the El Portal Administrative Site
Target Conditions for Vegetation and FuelsTarget conditions for vegetation and fuels in Yosemite have been established using information from a number of sources including scientific studies, monitoring data, and professional evaluations (table 2.3). The target conditions describe vegetative conditions in two ways: as a set of structural features for the vegetation types within Yosemite and as a set of fire-related ecosystem processes that help sustain the vegetation types. The target conditions are a measurable set of variables which provide parameters to assess vegetative condition and the effectiveness of the program. Fire management actions have been divided into two categories, restoration and maintenance, each of which has an associated set of defined target conditions. In general, target conditions for restoration are based on plant community structure while target conditions for maintenance are based on ecosystem processes. Restoration target conditions apply to plant communities that have missed three or more fire return intervals. Maintenance target conditions apply to plant communities that have missed less than three fire return intervals and are within their natural range of variability. The general objectives for vegetation in fire management terms are to: ¨ Restore fire to plant communities that have missed three or more fire return intervals. ¨ Maintain plant communities that have missed less than three fire return intervals and are within their natural range of variability. Restoration TargetsFire restoration actions are needed when an ecosystem has missed so many naturally occurring wildland fires that the types and ages of plants are not what would be expected in that vegetation type if lightning fires had been allowed to burn. Fire restoration actions aim to return plant communities to a vegetative structure that would allow natural ecosystem processes, including fire, to maintain them. The structural targets developed for major vegetation types of the Sierra (table 2.3) are used to determine whether an ecosystem is within its natural range of variability. Restoration targets are intended for vegetation types that exhibit structural conditions that are three or more fire return intervals outside of the natural, expected condition. Most areas slated for restoration are on the western side of the park. Areas that show the effects of long-term fire exclusion are more likely to experience a stand replacement fire that could result in a complete change in vegetation type. Reducing the fuel load either through prescribed burns or by removing live and dead vegetation and then burning the area would decrease the risk of a stand replacement fire and help restore the plant community to within its natural vegetative structure as measured by structural targets (table 2.3). Restoration targets were developed for each vegetation type using variables that measure plant community structure. These include gap distribution, density, frequency by species composition, and fuel load (table 2.3). Gap distribution describes the occurrence of open spaces in the forest canopy. Three gap sizes were used: 0.1-1 hectare (ha); 1-10 hectare; and 10-100 hectare. For example, restoration targets for ponderosa pine/mixed conifer forest show that small gaps should occur across 75-95% of the landscape, medium gaps should occur across 5-25%, and large gaps should occur across less than 1% of the landscape (table 2-3). Density is expressed as the number of trees per acre. For fire management analysis, trees are separated into two size classes. This division of trees into two size classes is based on the age to diameter relationships for certain tree species and the length of time fires have been suppressed. In general, we are assuming that trees less than 31.5” diameter breast height (dbh) have become established in the period since fires began to be suppressed and trees larger than 31.5” dbh were established before fire suppression activities began in Yosemite, as early as the 1860s. Recruitment of new trees and shade tolerant trees flourished when wildland fires were suppressed and over the decades these trees have grown without the influence of fire. Thus, existing density of trees less than 31.5” dbh are much higher than in pre-settlement forests. While we have made the preceding assumptions, we recognize that we do not have a complete picture of what Yosemite’s forests looked like before fire suppression (Stephenson 1999). The actual distribution of tree sizes should be measured in each stand before restoring the stand to natural densities by cutting trees. The current size break of 31.5” dbh should be applied with reason and prudence because the study trees were from a specific location and elevation. Measurements of trees at Yosemite may show that trees either larger or smaller than 31.5” dbh have become established since fire suppression, depending on site potential and tree species. For example, areas like Yosemite Valley and Hodgdon Meadow are exceptionally good sites for tree growth. At sites such as these, trees larger than 31.5” dbh could have established themselves since 1860 when the cavalry first began suppressing fires. Other locations like Mosquito Creek are less productive and the size break would probably be under 31.5” dbh. Frequency by species composition refers to the makeup of a stand. It is the composition of trees that comprise a given vegetation type. It was derived by counting the number of trees by species greater than 31.5” dbh in established fire effects study plots. If plots were not available in Yosemite for a particular vegetation type, data from fire effects plots in similar vegetation types in Sequoia and Kings Canyon National Parks were used. Fuel load is a measurement of dead and down wood, litter, and duff expressed in tons per acre. Dead and down fuels were evaluated across the landscape and put into categories: light fuel load is 5-30 tons per acre, moderate fuel load is 30-60 tons per acre, and a heavy fuel load is greater than 60 tons per acre. For example, target conditions for fuel load in ponderosa pine/mixed-conifer forest would be light across 20-40% of the landscape, moderate across 20-50% of the landscape, and heavy across 5-20% of the area. Fuel loads in ponderosa pine/mixed conifer forests currently exceed these desired conditions.
Table 2.3 Restoration Target Conditions Preliminary target conditions by vegetation type for restoring plant communities by reintroducing the natural fire regime in Yosemite National Park. Restoration target conditions are based on structural features of vegetation types. Variables are number and size of forest openings or gaps, tree size, species composition, and amount of live and dead vegetative fuels.
1 based on consensus expert opinion for Sequoia and Kings Canyon National Parks 2 based on fire effects monitoring data for ‘pre-settlement’ tree from Yosemite; additional databases may be available to refine targets 2a Sequoia and Kings Canyon National Parks fire effects monitoring data Table 2.4 Maintenance Target Conditions Preliminary target conditions by vegetation type, for maintaining the natural fire regime within plant communities in Yosemite National Park. Maintenance of ecosystems is based on ecosystem process variables of fire return interval, seasonality of fire occurrence, fire size, and severity.
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