Full opinion text
DECISION AND ORDER REYNOLDS, District Judge. In this action, filed April 2,1990, plaintiffs, three conservation groups, claim that the United States Forest Service (“the Service”) violated various statutory and regulatory provisions by failing to consider basic principles of ecology in developing a management plan for the Nicolet National Forest (“the Nicolet”). Plaintiffs farther claim that the Service failed to provide adequate opportunities for “remote” forms of forest recreation and faded to consider a sufficient range of alternative forest plans. Both sides have filed motions for summary judgment, on which oral argument was heard September 3, 1992. For reasons set forth below, the court now denies the motion filed by plaintiffs and grants the motion filed by defendants. This action is brought pursuant to the Administrative Procedure Act (“APA”), 5 U.S.C. § 701 et seq. Jurisdiction in this court is based upon 28 U.S.C. § 1331. I. Overview The Nicolet National Forest, whose boundaries encompass almost a million acres in northeastern Wisconsin, of which about 655,-000 acres are national forest land, is managed according to the prescriptions set forth in a rather detailed document, the “Land and Resource Management Plan,” issued by the Service. Development of the current plan, which covers the period from 1986 to 1995, began in 1980 under the direction of the Nicolet Forest Supervisor, Jim Berlin (“Berlin”). A draft version of the plan was formally issued to the public on November 9, 1984, along with a draft environmental impact statement comparing the impact of the draft plan to that of several alternative plans. There followed, pursuant to 16 U.S.C. § 1604(d), a period of public comment, as a result of which the draft plan was modified in certain respects. On August 11,1986, the Service’s Regional Forester for the Eastern Region (“Regional Forester” or “regional office”), which includes the Nicolet, issued the final plan, the final environmental impact statement (“FEIS”), and a Record of Decision explaining why the plan had been approved. The plan then was challenged in an administrative appeal by various citizens’ groups, including the instant plaintiffs. On February 22, 1988, Service Chief F. Dale Robertson (“the Chief’) issued a decision affirming the plan in part and remanding it in part to the Regional Forester. Plaintiffs Sierra Club, Wisconsin Forest Conservation Task Force, and Wisconsin Audubon Council, Inc., are organizations dedicated to the enjoyment, study, and conservation of forests and other natural resources. Members of each organization use the Nicolet for scientific and recreational purposes, which allegedly will be adversely affected by implementation of the plan. (Compl. at ¶¶ 5-7; Jan. 21,1992 Affs of George Hall, Emmet Judziewicz, Donald Waller, William Alverson, Jean Anderson, Jim Young, Clark Gaskill.) Plaintiffs raise three distinct but related claims. First, they claim that in developing the plan, the Service ignored important scientific principles and, as a result, failed to consider the plan’s effect on “biological diversity,” thereby violating the National Environmental Policy Act (“NEPA”), 42 U.S.C. § 4321 et seq., which requires a “hard look” at the environmental consequences of federal action, the National Forest Management Act (“NFMA”), 16 U.S.C. § 1600 et seq., which governs the development of forest plans and requires that they provide for biological diversity, and the Multiple-Use Sustained-Yield Act (“MUSYA”), 16 U.S.C. § 528 et seq., which bars impairment of the productivity of the land. Second, plaintiffs claim that the Service failed to provide adequate opportunities for “remote” forms of recreation, in violation of the NFMA, 16 U.S.C. §§ 1604(e)(1), (g), and associated regulations, which, together with MUSYA, 16 U.S.C. § 528, identify recreation as one of the purposes of the national forest system and require the Service to provide a “broad spectrum” of recreational opportunities and to inventory the forests’ recreational resources. Finally, plaintiffs claim the Service violated NEPA, 42 U.S.C. § 4332(2)(C)(iii), and associated regulations, by failing to consider an adequate range of alternative forest plans with more varied amounts of logging and road building. Because each of these claims is brought pursuant to the APA, the challenged action may be set aside only if shown to be “arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law.” 5 U.S.C. § 706(2)(A); Citizens to Preserve Overton Park, Inc. v. Volpe, 401 U.S. 402, 416, 91 S.Ct. 814, 823, 28 L.Ed.2d 136 (1971). With this standard in mind, the court will address the merits of plaintiffs’ claim, after first reviewing their standing to challenge the Nicolet forest plan and the “ripeness” of the instant dispute. II. Standing and Ripeness A. Background The plan, a document the size of a suburban phone book, establishes fairly specific objectives for recreational and commercial use of the Nicolet over the period of a decade or so and prescribes management practices necessary to achieve those objectives and to fulfill other statutory requirements. The objectives for recreational use are classified according to several different forms of recreation — “developed,” “dispersed,” “wilderness,” and hunting, fishing, and trapping— and are quantified in terms of “visitor days per year.” (Plan at 22.) The objective for timber harvesting is set at 97 million “board feet” of timber per year, allocated among six categories of timber type, each of which is subclassified according to harvest method, age-class, and forest district (there are four of them). (Id. at 22, 25-27, 33-35.) To accomplish these objectives, the plan sets forth a number of management prescriptions to be implemented over the course of ten years, specifying (among other things) the number of miles of roads to be maintained, closed, and newly constructed; the number of new campsites and trails to be constructed; and the acreage of “wildlife openings” to be maintained, trees to be harvested, and trees to be “regenerated.” (Id. at 23-24.) Aso, the plan divides the forest into dozens of smaller geographic sections, each of which is identified by one of 16 “Management Aeas” that represent different combinations of management practices and recreational environments. (Id. at 83-156.) Finally, the plan sets forth a number of forest-wide “guidelines necessary to implement” the plan’s management prescriptions. (Plan at 36, 37-82.) The guidelines range from general policy statements concerning, for example, the construction of trails and recreation areas, to quite specific instructions concerning timber harvesting methods, the protection of “sensitive” species, and the construction of roads. (Id.). B. Analysis A case or controversy for purposes of Afiele III arises where an injury, the invasion of a “concrete” and legally cognizable interest, has occurred or is “imminent,” is traceable to the defendant’s action, and is redressable by a decision in the plaintiffs favor. Lujan v. Defenders of Wildlife, — U.S. -, -, 112 S.Ct. 2130, 2136, 119 L.Ed.2d 351 (1992). There is no question that the alleged injury in this case concerns a concrete, legally cognizable interest — personal and professional enjoyment of the Nicolet environment — nor that plaintiffs and their members would themselves be “among the injured.” Sierra Club v. Morton, 405 U.S. 727, 734-35, 92 S.Ct. 1361, 1365-66, 31 L.Ed.2d 636 (1972). Defendants contend, however, that plaintiffs’ injury is not imminent because the source of the anticipated injury is not the plan itself but implementation of the plan, which must await the development of site-specific projects (such as individual timber sales) that will be subject to their own environmental analyses. See 40 C.F.R. §§ 1502.14(d), 1508.9(b). Thus, defendants insist, though plaintiffs will have standing to challenge such projects as they are developed, they do not have standing to challenge the plan as a whole. The court disagrees. Contrary to defendants’ assertion, the plan does not “merely state[] guidelines and parameters to be followed in the event a project is undertaken.” (Mar. 6, 1992 Def.Br. at 3.) While the plan certainly includes such guidelines and parameters, it also sets forth, as indicated in the previous section, a whole array of exceedingly specific management “prescriptions” that are in no sense conditional or optional. Consider the following regulations: Plans guide all natural resource management activities and establish management standards and guidelines for the National Forest System. They determine resource management practices, levels of resource production and management, and the availability and suitability of lands for resource management. As soon as practicable after approval of the plan, the Forest Supervisor shall ensure that, subject to valid existing rights, all outstanding and future permits contracts, cooperative agreements, and other instruments for occupancy and use of affected lands are consistent with the plan. Subsequent administrative activities affecting such lands, including budget proposals, shall be based on the plan. 36 C.F.R. §§ 219.1(b), § 219.10(d). Similarly, the FEIS provides: After the Plan is approved the [Nicolet office] will begin implementing it by producing the goods and services in the amounts specified in the Plan, using the management prescriptions specified, and adhering to the standards and guidelines included in the prescriptions. (FEIS, App. B at 8.) Thus, while the plan does not itself spell out the numerous site-specific projects necessary to its implementation, it clearly does require that such projects be undertaken, and it dictates their cumulative effect, which, after all, is what plaintiffs are concerned about. Moreover, barring amendment or revision (see 36 C.F.R. §§ 219.10(f), (g)), neither of which is said to be in the offing, the plan is certain to be implemented in its current form. Thus, because the current plan mandates, in quite specific terms, the very management activity that will ultimately cause plaintiffs’ injury, the fact that the Service has yet actually to inflict the injury through the development of site-specific projects does not render the injury “conjectural” or “speculative” and therefore does not deprive plaintiffs of standing to challenge the plan. Idaho Conservation League v. Mumma, 956 F.2d 1508, 1516 (9th Cir.1992). See also Rockford League of Women Voters v. United States Nuclear Regulatory Comm’n, 679 F.2d 1218, 1221-22 (7th Cir.1982). Plaintiffs also have standing to challenge the adequacy of the FEIS. Indeed, such a challenge may be brought even absent a showing that injury is imminent and redressable; it is enough that the alleged injury concerns a concrete and legally cognizable interest that “could” be impaired as a result of the agency’s failure to prepare the FEIS properly. Defenders of Wildlife, — U.S. at - n. 7, 112 S.Ct. at 2142 n. 7. In this case, plaintiffs contend, if the Service had considered basic ecological principles in its environmental analysis it might have sought to avoid or mitigate plan prescriptions that contribute to excessive forest fragmentation,. the source of plaintiffs’ injury. That gives plaintiffs standing to challenge the FEIS. Repackaging their position on standing, defendants also contend that since site-specific projects have yet to be developed, the dispute over the forest plan is not “ripe” for adjudication. Here, defendants rely principally upon Lujan v. National Wildlife Fed’n, 497 U.S. 871, 890, 110 S.Ct. 3177, 3189, 111 L.Ed.2d 695 (1990), which held that a general category of actions and decisions by the Bureau of Land Management was not “agency action” under the APA, 5 U.S.C. § 702, and therefore was not ripe for review, because the actions and decisions, though related as a factual matter, had not been formally grouped into a “completed universe.” Absent such formal grouping by the agency or by statute, the court held, a category of actions and decisions that may constitute a “program” in the abstract “cannot be laid before the courts for wholesale correction under the APA.” 497 U.S. at 893, 110 S.Ct. at 3191. Unlike the actions and decisions at issue in National Wildlife Fed’n, however, the collection of decisions that make up the forest plan is formálly treated as a single agency action. See: 36 C.F.R. § 219 Subpart A; 36 C.F.R. § 219.10(d) (providing for administrative appeal of “the Regional Forester’s decision to approve a forest plan”). Thus, notwithstanding the need to develop site-specific projects, the forest plan is ripe for review. Idaho Conservation League, 956 F.2d at 1518-19. The court now turns to the substance of plaintiffs’ claims. III. Biological Diversity A. Statutory, Regulatory Background The NFMA, enacted in 1976, was designed to provide a “comprehensive framework for the development and implementation of [forest] management plans” consistent “with the principles of multiple-use and sustained-yield” that had been set forth in MUS-YA. S.Rep. No. 94-893, 94th Cong., 2d Sess. at 8, 10 (1976), U.S.Code Cong. & Admin.News 1976, pp. 6662, 6668, 6671, Section 6(g) of the NFMA directs the Secretary of Agriculture to promulgate regulations governing the development of management plans. 16 U.S.C. § 1604(g). The regulations are to include, among other things, guidelines that: provide for diversity of plant and animal communities based on the suitability and capability of the specific land area in order to meet overall multiple-use objectives, and within the multiple-use objectives of a land management plan adopted pursuant to this section, provide, where appropriate, to the degree practicable, for steps to be taken to preserve the diversity of tree species similar to that existing in the region controlled by the plan. 16 U.S.C. § 1604(g)(3)(B). The required regulations, promulgated in 1979 and revised in 1982, include two sets of guidelines corresponding to the diversity language of Section 6(g)(3)(B). The first set concerns the place of biological diversity in forest planning generally: Forest planning shall provide for diversity of plant and animal communities and tree species consistent with the overall multiple-use objectives of the planning area. Such diversity shall be considered throughout the planning process. Inventories shall include quantitative data making possible the evaluation of diversity in terms of its prior and present condition. For each planning alternative, the interdisciplinary team shall consider how diversity will be affected by various mixes of resource outputs and uses, including proposed management practices. 36 C.F.R. § 219.26. The second set of diversity guidelines is addressed to the actual content of management plans: Management prescriptions, where appropriate and to the extent practicable, shall preserve and enhance the diversity of plant and animal communities, including endemic and desirable naturalized plant and animal species, so that it is at least as great as that which would be expected in a natural forest and the diversity of tree species similar to that existing in the planning area. Reductions in diversity of plant and animal communities and tree species from that which would be expected in a natural forest, or from that similar to the existing diversity in the planning area, may be prescribed only where needed to meet overall multiple-use objectives. 36 C.F.R. § 219.27(g). For purposes of these regulations, “diversity” means “the distribution and abundance of different plant and animal communities and species within the area covered by a land and resource management plan.” 36 C.F.R. § 219.3. Closely related to the diversity provisions (perhaps designed to implement them) are regulations concerning protection of the “Fish and Wildlife Resource.” 36 C.F.R. § 219.19. These regulations require, first, that the Service manage “[f]ish and wildlife habitat ... to maintain viable populations of existing native and desired non-native vertebrate species.” Id. Accordingly, habitat must be provided to support, at least, a minimum number of reproductive individuals and that habitat must be well distributed so that those individuals can interact with others in the planning area. Id. The second requirement of the fish and wildlife regulations is that the Service estimate and monitor the effect of forest management on the populations of certain “management indicator species.” 219.19(a)(l)-(7). These species, which may be plant or animal, vertebrate or invertebrate, must include, “where appropriate,” representatives of the forest’s threatened and endangered species, species with “special habitat needs,” common game species, “non-game species of special interest,” and species whose “population changes are believed to indicate the effects of management activities on other species ... or on water quality.” 36 C.F.R. § 219.-19(a)(1). In sum, the NFMA and associated regulations create three requirements related to biological diversity: that forest planning provide for diversity of plant and animal communities, that viable populations of vertebrate species be maintained, and that the effect of management prescriptions on populations of management indicator species be monitored. Defendants’ method of addressing these requirements is set forth below, followed by a discussion of the ecological principles that plaintiffs claim defendants ignored. B. The Service’s Approach to Biological Diversity 1. The Wildlife Habitat Diversity Index The Service claims it satisfied the NFMA’s diversity provisions by conducting the required population viability and indicator species analyses and by conducting a separate analysis of “vegetative diversity.” The latter analysis was based on the Service’s assumption that overall biological diversity was mainly a function of “diversity of habitats,” and that diversity of habitats was mainly a function of “vegetative diversity.” (FEIS, App. D at 3.) The level of vegetative diversity occurring throughout the forest was found to depend on three variables: distribution of timber type, variety of timber age-class, and the level of “wildlife management investment,” which refers to the percentage of land under a “high recreation/wildlife management intensity.” (FEIS, Chpt. 3 at 26-27, App. D at 28.) Distribution of timber type was deemed important because different timber types provide or are associated with different qualities of habitat. (Id., App. D at 21-25.) Tree types were deemed particularly beneficial to “wildlife habitat” if, among other things, their structure or canopy creates “cover,” if they are associated with diverse “understory” shrubbery, if they create “snags” for dens and the like, if they typically grow in stands of diverse tree species, and if they are harvested on a “short rotation.” (Id.) Based apparently on these criteria, the Service concluded that the best forest plan in terms of diversity would increase the total acres of Jack Pine, Balsam Fir, and Aspen, and decrease the total acres of Red Pine, White Pine, White Spruce, Mixed Hardwoods, and Lowland Conifers. (Id., App. D at 21-25.) Accordingly, the Service determined that the total acres of each timber type should account for the following percentages of the total forest acreage: Jack Pine, 4.3 percent (up from 2.5 percent); Balsam Fir, 4.7 percent (up from 3.4 percent); Aspen, 27.9 percent (up from 23.2 percent); Red Pine, White Pine, and White Spruce combined, 10.8 percent (down from 12.6 percent); Mixed Hardwoods, 41.2 percent (down from 46.5 percent); and Lowland Conifer, 11.1 percent (down from 11.8 percent). (FEIS, App. D. at 13, 16.) Variety of timber age-classes was included as the second variable in the Service’s diversity analysis apparently on the assumption that, like different timber types, trees at different stages of growth provide or are associated with different kinds of habitat. (FEIS, App. D at 25.) The Service found that, in general, the optimal mix of age-classes would be achieved by distributing tree populations evenly among different age-classes, resulting in a “balanced age class structure.” (Id., App. D at 25.) The following table sets forth the existing and desired age-class mix as determined by the Service: (Id. at 2-12 (Table 2-6).) As noted above, the third variable in the Service’s assessment of biological diversity was the percentage of forest land subject to a “high recreation/wildlife management intensity,” which reflects: the number of permanent forest openings maintained, the amount of special wildlife areas such as grouse hunter trail systems and deer winter range management areas, and ... the amount of on-the-ground wildlife coordination which is carried out in any alternative. (Id., App. D at 28.) Of these factors, the Service placed particular emphasis on the total acreage of permanent forest openings maintained, apparently because many species thrive on the edge of forested areas or in clearings, rather than within the forested areas themselves. (Id., App. D. at 27-28.) The Service found that for diversity purposes, the optimal number of acres under wildlife management investment would be 468,000, or 85 percent of the “total manageable lands” in the Nicolet. (FEIS, App. D at 29.) The optimal values for each of the three diversity variables are set forth not only for the forest as a whole, but also for each of four “socio-economic zones” into which the forest is divided. The zones represent different geographical areas of the forest and are associated with different demographic and economic patterns. (FEIS, Chpt. 3 at 44-45.) After assigning optimal values to each of the three variables, the Service used these values as benchmarks for estimating the degree to which each of the eight alternative forest plans would contribute to biological diversity. The result was a Wildlife Habitat Diversity Index, which lists the percentage of each alternative’s conformity to the optimal management prescriptions. {Id., App. D at 31.) For the timber type variable, that percentage is determined as follows: each timber type’s prescribed percentage of the total forest is subtracted from its optimal percentage, the differences added together, and their sum subtracted from 100. {Id., App. D at 30.) It is unclear exactly how the diversity indices for the other two variables were calculated. {Id., App. D at 29-31.) Because separate diversity indices were calculated for each of three variables and for each of four socio-economic zones, each alternative forest plan generated 12 sub-indices. To arrive at a total diversity index, the subindices were added together and their sum divided by 12, thereby according equal weight to each of the three variables. {Id.) The table below lists the Service’s diversity indices for each alternative, excluding the breakdown by socio-economic zone. {Id., App. D at 31 (Figure D-5).) As the numbers indicate, Alternative 6 was the alternative designed to maximize biological diversity. Alternative 5 represents the plan that was adopted. According to the FEIS, the Service compared the alternative forest plans on the basis of several variables that were not incorporated into the diversity analysis. (Id., App. D at 26-28.) Among these was total acreage of old-growth forest, of which the FEIS states: The total number of wildlife species associated with the mature and old growth forest condition is about equal to the number associated with the regenerating and young timber condition. * * * * * * Both managed and unmanaged old growth will occur as scattered small areas across the Forest with the exception of large designated wilderness areas. (Id., App. D at 26.) Another factor the Service studied but did not incorporate into the diversity analysis was total acreage of forest occurring in “large areas of low human disturbance.” (Id., App. D at 27.) Of this factor, which was quantified in terms of “total wilderness, old growth, and other modified road management areas in blocks over 1,000 acres,” the FEIS states: “Certain wildlife species are sensitive to human disturbance and are thus associated with large areas of no roads, closed roads, or reduced roads.” (Id.) 2. Population Viability Analysis The Service began its population viability analysis, required under 36 C.F.R. § 219.19, by compiling a list of “all rare and uncommon vertebrate wildlife species” and of various other species “associated with habitats subject to significant change through planning alternatives.” (Nov. 15, 1991, Defs Br., Ex. A at 1.) Sixty-five of the species on the list were identified as “needing” a population viability analysis. (Id., Ex. A at 2.) The sixty-five were then grouped by habitat type, resulting in fourteen categories of habitat. (Id., Ex. A at 10-11, Table 4.) The habitat for each of the 65 species was identified by reference to a 1984 inventory of the Nicolet’s species and associated habitats, in which “forested habitats” are divided into 17 different combinations of timber type and age-class, and “nonforested habitats” are divided into “upland openings,” “rural human settlements,” “open water,” “riparian zones,” and five categories of “wetlands.” (Id., Ex. C at 40-60.) From each of the 14 habitat categories into which the 65 species were grouped, the specie requiring the largest “territory” was selected for the viable population analysis, on the assumption “that if adequate habitat is available to maintain viable populations of these 14 species, then adequate habitat will be available for all associated species.” (Id., Ex. A at 2.) To determine whether viable populations of the 14 species would be maintained, the Service multiplied the amount of each specie’s habitat that would be available after 150 years under each alternative forest plan by the specie’s population density, resulting in an estimated population size. (Id., Ex. A at 12, Table 5.) The Wild Turkey, for example, is associated with Oak and has a population density of 1 per 100 acres; under Alternative 5, there would be 22,880 acres of Oak after 150 years, resulting in an estimated population size for the Wild Turkey of 229. (Id.) Based on estimated population size, the Service calculated the probability that the specie would begin to inbreed after 150 years. (Id., Ex. A at 27, Ex. C at 11.) An “inbreeding coefficient” of 0.5 or greater indicates that the specie will become extinct. (Id., Ex. C at 11.) Under Alternative 5, the forest plan, none of the 14 species analyzed for population viability would have an inbreeding coefficient of 0.5 or greater for the forest as a whole, though some of them would reach that number when population size is broken down by socio-economic zone. (Id., Ex. A at 27, 30.) 3. Management Indicator Species Analysis Pursuant to 36 C.F.R. § 219.19(a), the Service selected thirty-three species (no plants or invertebrates) as management indicator species for the Nicolet. (Nov. 15,1991, Defs Br., Ex. B at 23.) For each of them, the Service identified the specie’s associated habitat and multiplied the amount of such habitat provided for in each alternative forest plan by the specie’s population density, just as it had done for the species analyzed for population viability, to arrive at an estimated population size. (Id., Ex. B at 24-27, 29.) Further, the Service established a plan for monitoring the populations of the indicator species in the future. (Id., Ex. B at 32-40.) C. Plaintiffs’ Objections to the Service’s Approach 1. Conservation Biology Plaintiffs challenge the Service’s approach to diversity largely on the basis that it ignored the ecological consequences of “forest fragmentation,” as predicted by the science of conservation biology. This science demonstrates, plaintiffs say, that biological diversity of a particular region depends on several interrelated factors bearing upon the quality of the region’s habitats. Prominent among these factors are the size of the habitats, or “patch size,” and the extent of disturbance -within the habitats. (VII Admin.Ree. at 1848-1854.) The science holds that a habitat must be sufficiently large and undisturbed that “minimum viable populations of sensitive species [can remain or recolonize within the habitat] after a catastrophic disturbance.” (Id. at 1851.) Based upon the size of the area typically affected by such disturbances, plaintiffs estimate that a patch size of 50,000 acres is minimally necessary. (Id. at 1852.) Another factor that conservation biology deems relevant is the degree of accessibility between similar geographical habitats. The science predicts that as similar habitats become increasingly isolated from each other, biological diversity declines because organisms cannot survive disturbances in one habitat by migrating to another. (Id. at 1863-74.) This is known as the theory of “island biogeography,” so-named because it is derived from the study of biological diversity on oceanic islands. (Id. at 1863-64.) The same theory has been applied to purely terrestrial habitats, where, for example, “islands” of old-growth forest are surrounded by a “sea” of young or clear-cut forest, thereby isolating the organisms dependent on old-growth habitat. (Sept. 9,1991 Kuhlmann Aff., Ex. N(13) at 63; VII Admin.Ree. at 1864, 1873; Sept. 12, 1991 Pl.Br. at 24-27.) The third factor plaintiffs identify as crucial to conservation biology is the extent to which a habitat is penetrated by adverse external forces, or “edge effects,” from adjacent habitats. (Id. at 1874^90.) Edge effects would include, for example, the invasion of an old-growth forest by plants and animals (deer are of particular concern) from a surrounding younger forest. (Id. at 1877-78, 1888.) If the invasion extends, say, a quarter-mile into the old-growth forest, and the entire habitat is only a half-mile wide, the organisms dependent on the old-growth forest may be effectively deprived of their habitat. (Id. at 1875.) Thus, the presence of edge effects is believed to be pertinent to determining how large a habitat must be. Plaintiffs contend that conservation biology and the associated concepts of “patch dynamics,” “island biogeography,” and “edge effects,” represent well-accepted scientific theory. The theory is based, according to plaintiffs’ submissions to the Service, mainly on scientific literature dating from the 1970s (Id. at 1849-51, 1855, 1860, 1862, 1864-67, 1871-72, 1876-80, 1885), though it relies as well on scholarship of the 1960s. (Id. at 1855, 1863, 1864.) The bibliography plaintiffs submitted to the Service includes a number of sources from the 1970s and early 1980s discussing, in terms of conservation biology, the biological significance of a forest habitat’s size, internal fragmentation, isolation from other habitats, and edge effects. (Sept. 12, 1991 Pl.Statement of Facts at 23-36; VIII Admin.Ree. at 2158-66, 2191-97.) Several of these sources confirm the applicability of island biogeography to continental forest reserves. (Sept. 12, 1991 Pl.Statement of Facts at 23-36; VIII Admin.Rec. at 2162, 2163, 2165, 2166, 2197.) Relying on some of the same sources, a 1983 article published by the Service (and submitted to the court by defendants) states: It is man’s indirect effects, through population isolation and habitat alteration (a form of competition for resources), that hold the greatest danger for most species.... * * * * * * Man dramatically changes the natural patterns of habitats through land use decisions. This often isolates wildlife and fish populations. And, man alters the habitats within a particular land use situation. This often fragments and reduces the populations of some species. (Nov. 15, 1991 Defs Br., Ex. E at 6.) The principal author of that article, United States Fish and Wildlife Service official Hal Salwasser, commented in another paper: “Island Biogeography theory and empirical knowledge are the foundation of the role of pattern diversity in National Forest Management.” (VII Admin.Rec. at 1873.) Plaintiffs’ general position was endorsed before the Service by thirteen experts on biological diversity, they being of the unanimous opinion that such diversity cannot be maintained in the Nicolet unless a meaningful portion of it is reserved for large tracts (i.e., at least 30,000 to 50,000 acres) of relatively undisturbed forest. (VIII Admin.Rec. at 2167-2191.)- As one expert put it: Supporting large reserves these days is like supporting motherhood. The overwhelming consensus among ecologists and biogeographers is “the larger the better.” (Id. at 2186.) Accordingly, plaintiffs proposed on administrative appeal that the Nicolet plan be modified to provide for the establishment of three “Diversity Maintenance Areas” (“DMAs”), two consisting of about 60,000 acres and the third consisting of about 40,000 acres; together, these areas would account for almost a quarter of the national forest. (VII Admin.Rec. at 1923.) No timber harvesting or road construction would take place on the DMAs, according to plaintiffs’ proposal, and all existing roads, save town roads, county, state, and federal highways, and certain Service “class A roads,” would be “closed and gated.” (Id.) The DMAs would remain available, however, for other activities such as “hiking, fishing, skiing, hunting, camping and snowmobiling on designated trails.” (Id.) Plaintiffs submitted maps describing where each of the DMAs should be situated. (Id. at 1705-08.) 2. The Service’s Response to Plaintiffs’ Position The Service declined to set aside undisturbed areas of the size proposed by plaintiffs and chose not to address the issue of forest fragmentation because it found that the theory of island biogeography had not been shown to be applicable to the habitats of the Nieolet. (Plan at 17; Record of Decision at 11, 16-18; Sept. 12, 1991 Kuhlmann Aff., Ex. N(16) at 2.) That finding was based on the fact that the theory, according to the Service, had been developed mainly in studies of non-forest habitats such as oceanic islands and deserts. (Sept. 12, 1991 Kuhlmann Aff., Ex. N(16) at 2.) The Service noted, further, that to the extent the theory had been applied to forests, “[t]he majority of the research has been conducted in the Pacific Northwest’s old growth forests which are managed exclusively under the even aged system,” rather than under the system of combined even-aged and uneven-aged management followed in the Great Lakes area. (Plan at 17; Record of Decision at 17.) The Service also concluded that even if island biogeography were found applicable to the Nieolet, still the theory would not require the establishment of large blocks of undisturbed forest. The Service cited biologist Larry Harris, author of “The Fragmented Forest,” for the proposition that biological diversity could be preserved by maintaining numerous small habitats in place of a few large ones, and for the further proposition that the need for large habitats is minimized if timber is harvested on “long rotation” and by selective cutting. (Sept. 12, 1991 Kuhlmann Aff., Ex. N(16) at 2.) Thus, according to the Service, the Plan should satisfy plaintiffs’ concerns since it creates numerous undisturbed habitats of smaller size and since much of the forest is harvested by long-rotation selective cutting. (Id.) The idea that island biogeography is of uncertain application finds some support in articles presented at a 1982 workshop, the purpose of which was “to identify the current state of information and the future needs to implement the NFMA provision for diversity on national forests.” Cooley, J.L. and Cooley, J.H. (eds.), Natural Diversity in Forest Ecosystems: Proceedings of the Workshop (“Workshop”) at i (1984). Referring to island biogeography, for example, one article (not written by Service personnel) states: Considerable disagreement still exists over the application of these equilibrium principles, first developed for islands, to landscape management. There is, however, no question that landscape patterns greatly affect species diversity of the individual communities on that landscape. An understanding of how specific landscape features (e.g., community size, separation, and the presence of corridors) affect the processes that determine diversity should be a primary research goal. Christensen, N.L., and Peet, R.K., “Measures of Natural Diversity,” Workshop at 54-55 (citations omitted). Similarly, according to an article by one of the 13 experts who supported plaintiffs’ position before the Service: Because the degree of insularity created by habitat conversion can vary, it is appropriate to question greatly the applicability of results of studies of true islands to habitat islands. [T]he application of conservation biology to the problem of minimum area requirements is still very much in the research and development stage. Nonetheless, responsible management of natural diversity on national forest lands requires that at least these fundamental concepts be considered. However, they should be viewed merely as starting points for more comprehensive management planning efforts than have been required or even technically possible in the past. Wilcox, B.A., “Concepts in Conservation Biology: Applications in the Management of Biological Diversity,” Workshop at 164, 170. The Service, however, did not reject plaintiffs’ proposal only on the ground that its application was uncertain. Rather, the Service also predicted that the proposal would be measurably less beneficial than the forest plan in terms of preserving biological diversity. (Record of Decision at 17.) According to the Service’s diversity index, a forest plan incoiporating plaintiffs’ proposed DMAs — Alternative 7 — would, after 150 years, result in a “low” level of diversity, whereas the preferred forest plan would result in a “high” level. (Id.; see supra at 15.) Though the Service did not directly consider principles of conservation biology, it did estimate, as noted above, the total acreage of “upland old growth” that would result from each alternative plan, as well as the number of acres of “wilderness, old growth, and other modified road management areas” found in blocks of 1,000 acres or more. (FEIS, App. D at 26-27.) Neither measure, however, was factored into the diversity index. Under the forest plan, according to the impact statement, “old growth will occur as scattered small areas across the Forest with the exception of large designated wilderness areas.” (Id., App. D at 26.) 3. The Chiefs Decision Regarding Diversity The Chief found that the diversity provisions of the NFMA and associated regulations establish “no additional requirements beyond those identified” in the regulations concerning population viability, management indicator species, and the protection of the habitat of threatened and endangered species. See 36 C.F.R. § 219.19. (I Admin.Rec. at 32.) Thus, by complying with these regulations, the Chief concluded, the Regional Forester ensured that the plan provided for biological diversity; no additional inquiry into the principles of conservation biology or anything else, for that matter, was required. (Id. at 34-35.) The Chief separately concluded that the Regional Forester was correct in declining to consider the predictions of island biogeography. “Island biogeography theory is not new,” the Chief found, “but until there is conclusive, empirical evidence that the conclusions, hypotheses, or predictive capabilities for terrestrial ecosystems are valid, it is proper to acknowledge it as untested theory.” (Id. at 36.) D. Analysis The Service’s assessment of biological diversity is said to have violated not only the NFMA but also NEPA and MUSYA. The latter statute requires that national forests be managed for the “multiple use” of various resources, including “recreation, range, timber, watershed, and wildlife and fish,” and that the “periodic output” of such resources be maintained “in perpetuity ... without impairment of the productivity of the land.” 16 U.S.C. §§ 528, 529, 531. This language, however, really just amounts to a statement of principle; it offers no guidance on how to assess the particular management activity at issue in this case. See Perkins v. Bergland, 608 F.2d 803, 806-7 (9th Cir.1979). Because the NFMA speaks directly to that issue, MUSYA need not be considered further. NEPA requires that federal agencies take a “hard look” at the significant environmental consequences of proposed projects and disclose the same in a “detailed statement.” Robertson v. Methow Valley Citizens Council, 490 U.S. 332, 348-50, 109 S.Ct. 1835, 1844-45, 104 L.Ed.2d 351 (1989); 42 U.S.C. § 4332. The court finds no reason to treat this requirement separately from the NFMA requirement that forest plans “provide for the diversity of plant and animal communities.” 16 U.S.C. § 1604(g)(3). For each statute, the ultimate question, as plaintiffs present it, is the same: What must the Service do to analyze properly the effect of its forest plans on biological diversity? Again, the NFMA deals with that question specifically, whereas NEPA is of far broader application. Nevertheless, the court assumes that the analytical standards developed under NEPA bear upon the quality of the analysis required to address the environmental factors identified in the NFMA. Under NFMA regulations, forest planning in general must “provide for diversity of plant and animal communities and tree species,” and management prescriptions, “where appropriate and to the extent practicable,” must “preserve and enhance the diversity of plant and animal communities ... and the diversity of tree species.” 36 C.F.R. §§ 219.-26, 219.27(g) (quoted in full, supra at 10). Diversity refers to “the distribution and abundance” of the objects in question. 36 C.F.R. § 219.3. Plaintiffs contend that the Service cannot have properly addressed the specified types and elements of diversity without attention to principles of conservation biology, for such principles are known to be critical to the viability of individual species and to an understanding of the structural differences among biological “communities.” Both the NFMA and NEPA require that environmental analyses be founded upon an “integrated” understanding of the major natural and social sciences. 40 C.F.R. § 1502.6; 36 C.F.R. § 219.5(a). In particular, NEPA requires consideration of “ecological” effects, “such as the effects on natural resources and on the components, structures, and functioning of affected ecosystems.” 40 C.F.R. § 1508.8. The NFMA, similarly, reveals an ecological bent in its emphasis on diversity of biological “communities.” 16 U.S.C. § 1604(g)(3); 36 C.F.R. §§ 219.3, 219.26, 219.27(g). Plaintiffs contend that these explicit and implicit references to ecology, together with the “hard look” principle underlying NEPA require the Service to take account of the basic ecological principles bearing on biological diversity, prominent among which are the principles of conservation biology. Plaintiffs have presented the agency and the court with a wealth of authority in support of the theory that principles of conservation biology concerning habitat size, internal fragmentation, edge effects, and island bio-geography are relevant to an ecosystem’s ability to sustain a diversity of organisms. (Supra at 1537-39.) Defendants, furthermore, have offered nothing that directly contradicts the plaintiffs’ scientific analysis. Indeed, certain aspects of it have been endorsed by Department of Agriculture officials. (Supra at 1538.) Thus, the court can safely assume that the principles of conservation biology set forth by plaintiffs represent sound ecological theory. Whatever their theoretical validity, however, considerable uncertainty seems to surround the question of how exactly these principles should be applied. Nowhere in plaintiffs’ exhaustive briefs and supporting materials does there appear any suggestion of what methodology the Service should have used to incorporate principles of conservation biology into its planning process. Before the agency, plaintiffs came up "with a fairly straightforward application of the science in their proposed creation of three DMAs. (Supra at 1538.) In this action, however, plaintiffs challenge not the Service’s rejection of that proposal but rather its failure to consider the scientific principles upon which the proposal was based. (Dec. 20, 1991 Pi’s Reply Br. at 4 n. 5.) It is therefore incumbent upon plaintiffs to explain how, precisely, those principles might have been considered; yet no such explanation has been given. Further, plaintiffs have failed to respond to defendants’ assertion that empirical studies of island biogeography have been conducted only in ecosystems differing substantially from the Nicolet and that such studies therefore do not have equal significance in that forest. (Supra at 1539.) Nor have plaintiffs answered defendants’ statement that, according to at least one authority on conservation biology, biological diversity is not dependent on the maintenance of a few large habitats but also can be preserved by maintaining numerous small ones, as defendants purport to have done in their forest plan. (Supra at 1539.) Uncertainties such as these are reflected as well in articles written by non-Serviee scientists, who state, in effect, that while conservation biology is important and should be considered, how to consider it remains an open question. (Supra at 1539-40.) Moreover, even if plaintiffs had identified some definite manner of applying conservation biology to forest planning, still the court would be reluctant to conclude that the Service acted irrationally in failing to embrace that science. When the NFMA regulations were first proposed in the late 1970s, the committee of scientists charged with reviewing them concluded that the regulations should not specify any particular manner of providing for biological diversity: [T]here remains a great deal of room for honest debate on the translation of [the NFMA’s biological diversity provision] into management planning requirements and into management programs. * * * * * * [W]e believe it impossible to write regulations which are specific on how this [i.e., providing for biological diversity] is to be done in all regions, in a wide variety of vegetation types, and with a wide range of natural and human factors to consider. * * * * * * No matter how diversity is defined, its measurement is complex. We have studied the question as to whether the regulations should specify use of a diversity index to measure diversity and to monitor effects of management ..: Although several mathematical formulations have been used in ecological research, there is no substantial agreement on the meaning or significance of the figures derived. Thus, we believe use of any of the present diversity indices would divert attention from the objective of considering variety throughout the planning process. 44 Fed.Reg. at 26609 (1979). The committee’s comments on diversity make no reference to the scientific principles plaintiffs have discussed here. Id. at 26599-26630. In view of the committee’s decision not to prescribe a particular methodology and its failure to mention the principles that plaintiffs claim were by then well established, the court cannot fairly read those principles into the. NFMA, particularly since their actual application, as noted above, is subject to debate. The court’s unwillingness to impose upon the Service a particular scientific theory reflects not only the experience of the committee of scientists, but also the more general idea that in areas of scientific uncertainty the agency’s choice of methodology is entitled to considerable deference. Baltimore Gas & Elec. Co. v. Natural Resources Defense Council, Inc., 462 U.S. 87, 103, 103 S.Ct. 2246, 2255, 76 L.Ed.2d 437 (1983); Central Arizona Water Cons. Dist. v. United States Envtl. Protection Agency, 990 F.2d 1531, 1540 (9th Cir.1993). The court concludes, therefore, that the Service did not act irrationally in failing to base its diversity analysis on the principles of conservation biology set forth by plaintiffs. This does not mean, of course, that the Service is relieved of its obligation to study the effect of the forest plan on biological diversity; it only means that, in doing so, the Service was not bound to apply the particular scientific theory that plaintiffs espouse. The court now turns to the distinct problem of whether the Service’s chosen methodology rationally addressed the elements of diversity set forth in the NFMA. The Service’s diversity analysis consisted of three steps. First, the Service determined how each of the forest plans, including the one deemed optimal for diversity, would affect tree species and age-class composition in the forest’s four socio-economic zones. (Supra at 1533-35.) This determination was believed to be important because of the assumption that different combinations of tree species and age-class are critical elements of habitat for various groups of species. (Id.) Second, the Service converted the prescriptions determined in the first step into percentages, representing the extent of each forest plan’s conformity to the tree type and age-class prescriptions deemed optimal for diversity. (Supra at 1534-35.) Third, based on the results of the first step and on assumptions regarding habitat associations and population density, the Service predicted how each forest plan would affect the population sizes of numerous management indicator species, as well as the likelihood of inbreeding for species subject to the population viability analysis. (Supra at 1536-37.) For the most part, aside from criticizing this methodology for its failure to consider conservation biology, plaintiffs do not challenge the assumptions underlying the methodology or the manner in which it was conducted. Plaintiffs express some disagreement with the Service’s choices of species for the analyses of management indicator species and population viability, but they have not explained how those choices were irrational or otherwise legally deficient. (Sep. 12,1991 Pl.Statement of Facts at 94-98.) Plaintiffs do contend, however, that the Service’s analysis failed to examine the effect of the forest plan on diversity of biological “communities,” as distinct from diversity of “species.” The NFMA and associated regulations plainly require the Service to provide for both forms of diversity (though without explaining the difference between the two). See 16 U.S.C. § 1604(g)(3); 36 C.F.R. §§ 219.3, 219.26, 219.27(g) (all quoted in full, supra at 1532-33). Yet the Service, plaintiffs insist, really only considered diversity of species: it estimated, for each forest plan, the total acreage of various tree species and the aggregate populations of numerous animal species, but made no attempt to survey and study the broader communities in which these species live. The Service does not purport to have examined biological communities directly. Rather, it assumed that a diversity of communities necessarily would follow from a diversity of habitats, that forested habitats are defined largely by the species and age-classes of trees they contain, and that, therefore, an adequate mixture of tree species and age-classes necessarily would yield a diversity of habitats. (Supra at 1533.) The importance of tree species and age-classes, according to the Service, is that they create or are associated with different physical structures (mainly canopy and understory), which in turn benefit different groups of animals. (Supra at 1533-34.) Thus, though the Service paid particular attention to tree species and age-classes, it did so on the theory that these factors are representative of whole communities, a theory that plaintiffs have not directly contested. The Service applied this theory by prescribing, for each of the forest’s four socioeconomic zones, a mix of tree species, tree age-classes, and wildlife openings deemed optimal for wildlife diversity; the forest plans were then compared on the basis of their conformity to the optimal prescriptions. (Supra at 1534-35.) The general principles underlying the determination of optimal prescriptions are more or less evident. For the age-class variable, the idea was to achieve an even distribution among several age-classes; for the timber-type variable, to increase the acreage of those timber types deemed particularly beneficial for wildlife diversity; and for the wildlife investment variable, to increase the total acreage of wildlife openings throughout the forest. (Supra at 1533-35.) If these general principles are evident from the FEIS, however, the manner in which they were translated into actual numbers is not. The FEIS does not explain, for example, why the Service chose 27.9 percent as the optimal forest-wide Aspen percentage, or why it chose 45 percent as the optimal percentage of Mixed Hardwoods in the 11- to 60-year age-class. (Supra at 1533-34.) If the Service used some particular formulae to arrive at these and other numbers underlying the diversity index, or at the parameters from which the numbers were selected, one would have hoped that the formulae would be set out in the FEIS or in a referenced document. Nonetheless, the court does not find that the Service’s method of determining the optimal prescriptions was irrational. The failure to describe that method in detail suggests a degree of arbitrariness in the selection of the optimal prescriptions, but not so much as to undermine the analysis as a whole. The general principles underlying the selection of optimal prescriptions are identified and explained, and plaintiffs have not attempted to show, nor has the court found, that the prescriptions themselves are at all inconsistent with those principles. Further, there is no basis in the record for questioning the method by which the optimal prescriptions and the prescriptions of the various alternative plans were converted, for purposes of comparison, into the percentages shown in the diversity index. Thus, the court concludes that the Service did not act irrationally in assuming that it could provide for an “abundance” of different biological communities — “abundance” being the first of two components of diversity under the NFMA, 36 C.F.R. § 219.3 — by prescribing a certain mix of tree species, tree age-classes, and wildlife openings throughout the forest, and did not act irrationally in applying that assumption through development of the diversity index. The second element of diversity of communities is their “distribution” throughout the planning area. 36 C.F.R. § 219.3. Though the parties really have not discussed this point, the court concludes that the Service rationally addressed this element of diversity as well. It did so by developing and examining the prescriptions deemed critical to diversity (i.e., tree type composition, age-class variety, and wildlife management investments) not only at the level of the forest as a whole but also at the level of the socioeconomic zones, the four geographic regions into which the forest has been divided. (Supra at 1534-35.) Ideally, perhaps, the Service would have conducted a more precise analysis of community distribution, but in the absence of evidence that such an analysis was feasible, the court cannot find that the Service’s more general approach was irrational. For the foregoing reasons, the court concludes that the Service’s analysis of biological diversity satisfied the requirements of the NFMA, NEPA, and associated regulations. IV. Recreation A. Background 1. Variety of Recreational Opportunities Under the NFMA and MUSYA, the Service, in administering the national forests, must “provide for multiple use and sustained yield” of forest resources, including “outdoor recreation.” 16 U.S.C. § 1604(e)(1); 16 U.S.C. §§ 528, 529. Accordingly, Service regulations state: To the degree consistent with needs and demands for all major resources, a broad spectrum of forest and rangeland related outdoor recreation opportunities shall be provided for in each alternative [management plan]. 36 C.F.R. § 219.21. Pursuant to this requirement, the Service in 1982 adopted a new system of classifying recreational opportunities called the “Recreation Opportunity Spectrum” (“ROS”) (VIII Admin.Rec. at 2022.) The ROS, which is not itself prescribed by regulation, consists of six categories of recreational environments — “primitive,” “semi-primitive nonmotorized,” “semi-primitive motorized,” “roaded natural,” “rural,” and “urban” — each of which is associated with its own narrative description and with rather precise standards of forest management. (FEIS at 7-9; III Admin.Rec. at 497-515.) The forest plan purports to set aside 63,-158 acres of land classified as semi-primitive nonmotorized (found in Management Areas 5, 6.2, and 9.2), 146,400 acres of land classified as semi-primitive motorized (found in Management Areas 1.2, 2.2, 3.2, 4.2, and 6.3), and 443,152 acres of land classified as roaded natural (found in Management Areas 1.1, 2.1, 3.1, 4.1, 8.1, 8.2, and 9.1). (Plan at 84-85.) On the ROS, the latter classification represents areas with “a high degree of user interaction,” whereas the semi-primitive classification refers to areas of “relative” or “moderate” isolation. (FEIS at 7-9.) Accordingly, the ROS applies different management standards to semi-primitive and roaded natural areas. In semi-primitive areas, trail density is limited to 2 miles per square mile, campgrounds contain no more than 10 sites, the road system is of “low density,” power tools are used only during periods of “low or no recreation,” and “vegetative management” is designed primarily to “enhance recreational experience,” with timber production as a secondary goal. (Ill Admin.Rec. at 499-502.) In roaded natural areas, by contrast, trail density is limited to 3 miles per square mile, campgrounds contain no more than 100 sites, the road system is of “moderate density,” there is no restriction on the use of power tools, and “vegetative manipulation” is designed to “meet resource [i.e., timber production] and recreation objectives.” {Id. at 503-04.) The other significant difference between semi-primitive and roaded natural areas, according to the ROS, is in their respective “Visual Quality Objectives” (“VQOs”), which describe the eonspicuousness of management activity. On the Nicolet, there are three possible VQOs. (Plan at 41-42.) A VQO of “retention” applies where “Management activities are not evident to the casual forest visitor.” {Id. at 186.) A VQO of “partial retention” applies where “[h]uman activities may be evident but must remain visually subordinate to the characteristic landscape.” {Id.) And a VQO of “modification” applies where “[h]uman activity may dominate the characteristic landscape but must, at the same time, follow naturally established form, line, color and texture.” {Id.) According to the ROS, the modification VQO is not appropriate for areas designated semi-primitive, but may be appropriate for areas designated roaded natural. (Ill Admin.Rec. at 500, 502, 504.) Berlin, the Nicolet Supervisor, was not a fan of the ROS. The problem with it, in his view, was that its standards for logging and road construction would effectively eliminate timber production on lands classified as semi-primitive. (VIII Admin.Rec. at 2016.) Berlin felt that such a restriction on the use of the land was appropriate only in eongressionally-designated -wilderness area. {Id. at 2017.) Accordingly, Berlin proposed early in the planning process that the semi-primitive nonmotorized classification in the Nicolet be reserved exclusively for wilderness area, leaving the rest of the forest under the road-ed natural classification. {Id. at 2021.)