CFA Reports

SNEP Report: Conflicting Findings

The Sierra Nevada Ecosystem Project Report (SNEP) is an assessment of the Sierra Nevada ecosystems from the scientific view point, which in general, considers nature the elite manager. The report is set in the context of 3000 years of human use in the Sierras.

“Archaeological evidence indicates that for more than 3,000 years Native Americans practiced localized land management for utilitarian purposes, including animal hunting, forest burning, seed harvesting, pruning, irrigation, and vegetation thinning. These practices no doubt influenced resource abundance and distribution in areas of early human settlement.”

The simplest summary is contained in the SNEP team press release.

“A major study of the Sierra Nevada indicates that much of the mountain range is in fairly good health now but rapid population growth, ongoing neglect and pollution from the Central Valley threaten the future of the region’s forests, species diversity, and air and water quality.”

This somewhat positive view is not readily apparent from reading the 22 page Summary. Sierra concerns are the primary feature while scattered throughout the report are findings that the Sierras are better ecologically than the rest of California. The Summary of the SNEP report is filled with conflicting information. An accurate assessment can only be made after a thorough review of the other 3000 pages, one quarter of which will not be complete until August.

The following is a sample of the conflicts presented in the Summary.

Concern:

“Timber harvest, through its effects on forest structure, local microclimate, and fuel accumulation, has increased fire severity more than any other recent human activity. If not accompanied by adequate reduction of fuels, logging (including salvage of dead and dying trees) increases fire hazard by increasing surface fuels and changing the local microclimate. Fire intensity and expected fire spread rates thus increase locally and in areas adjacent to harvest.”

“Although silvicultural treatments can mimic the effects of fire on structural patterns of woody vegetation, virtually no data exist on the ability to mimic ecological functions of fire... Similarly, although combining managed fire with silvicultural treatments adds the critical effects of combustion, the ecological effects and fire hazard reduction of this approach are largely unknown.”

Conflict:

“However, logging can serve as a tool to help reduce fire hazard when slash is adequately treated and treatments are maintained.”

“Current fuel levels and projected future uses in these areas [urban interface] are incompatible without active fuels management.”

Concern:

“Losses of regional and local genetic diversity may be precursors to population extinction: once lost, genetic diversity may be irrecoverable. By their nature, timber harvest and forest regeneration have potentially large impacts on diversity, but their impacts can be mitigated by policy.”

“The primary impact of 150 years of forestry on middle-elevation conifer forests has been to simplify structure (including large trees, snags, woody debris of large diameter, canopies of multiple heights and closures, and complex spatial mosaics of vegetation,) and presumably function of these forests.”

Conflict:

“Each vegetation type in the Sierra is in itself a mosaic. Small changes in topography, differences in soil and rock characteristics, and the history of disturbances (fire, storm blowdown, insect and pathogen activity, avalanches) contribute to the complex mixture of patches that characterizes Sierran forests. Plant patterns vary not only from place to place in the Sierra but also over time. This complexity at the local scale makes it difficult to map vegetation, to generalize relationships of structure to function, and to assess forest conditions.”

“Conifer forest habitats in general have been less extensively and less severely modified than foothills and riparian communities.”

“Although the situation in the Sierra differs from that in forests in the Pacific Northwest, where fragmentation leaves remnant old-growth patches surrounded by large openings, functionally the Sierran forests have been fragmented to a lesser degree by simplification.”

“The image evoked popularly by the term old growth, that is, extensive uniform stands of even-aged, old trees, although descriptive of some Pacific Northwest forests, does not fit the complex and heterogenous Sierran forests.”

“Impacts to plant populations have come largely from settlement, grazing, and fire suppression.”

“The Sierra Nevada today is rich in vascular plant diversity.”

Concern:

“Many native Sierran species are adapted to habitats maintained by the pre-settlement fire regime. Although only a handful of species require late successional habitats, many more depend on the presence of large, old trees, snags, and logs in Sierran woodland and forest communities for some part of their life cycle.”

“On average, national forest have about 25% the amount of the national parks, which is an approximate benchmark for pre-contact forest conditions. East-side pine forests have been especially altered. Human activities, particularly timber harvest, indiscriminate burning in the nineteenth century, and fire suppression in the twentieth century, have drastically reduced the extent of late successional forests through the removal of large trees and woody debris and dense ingrowth of shade-tolerant tree species, leading to greater stand uniformity over large areas and loss of landscape diversity.”

Conflict:

“Despite alteration of the national park forests due to fire suppression, forests in the park represent the best available benchmark for presettlement amounts of late successional forest at these elevations in the Sierra.”

“Although the national parks contain large blocks of high-quality late successional forest, similar, if considerably smaller, patches are relatively well distributed throughout the Sierra.”

“Late successional old-growth forests of middle elevations at present constitute 7-30% of the forest cover, depending on forest type.”

“Depending on forest type, about 19% of the current distributions of middle-elevation conifer forest types are presently in high-quality late successional condition.” (Emphasis added). (Note: environmental leaders have claimed for years that only 5% remained. Late successional forests are one of five seral stages, which, given even distribution between seral stages, would ideally represent 20% of the forest.)

“Nineteen percent of the mapped polygons were ranked as structural class 4 and 5. Substantially more areas were rated as structural class 3 (29% of the total)... About half the 3-rated polygons have a substantial portion of their area (more than 25%) in patches ranked 4 and 5.”

The proportion of polygons (82%) with rankings of 3,4, and 5 in the national parks is the best available indicator of conditions that prevailed in the Sierra Nevada before Euro-American settlement and is nearly twice the proportion on the national forest lands (42%).

“Including polygons ranked 3 or higher, the proportion of late successional forest is 47% on all federal lands, 42% on national forests and 82% in national parks.

“Many of the more open stands (rank 4) with large-diameter trees, small gaps, and open understories of low shrubs or herbs contribute more useful late successional habitat than some of those ranked 5 and are less vulnerable to stand-destroying fire.”

“Also, the degree of past human influence on polygons was a strong component of the rankings; a polygon that had experienced significant past human-caused disturbance tended to be ranked lower than an otherwise similar polygon without such influences.”

“Despite timber harvest, fires, livestock grazing, and mining, there is still a high level of continuity in middle-elevation forest landscapes. The forest cover at these elevations is relatively continuous, and most forested stands have sufficient structural complexity to provide for at least low levels of late successional forest functions.”

“In El Dorado County, all adequate BMA [biodiversity management area] solutions required the inclusion of significant private lands, because many important biological communities are almost entirely unrepresented on the public lands.” (Credit: intensive management on private lands?)

“Despite 150 years of Euro-American timber harvest activity in the Sierra Nevada, clear-cut blocks larger than 5-10 acres are at present uncommon in the conifer forests of the Sierra Nevada, and tree cover is relatively continuous.”

Concern:

“Sixty-nine species of terrestrial vertebrates (17% of the Sierra fauna) are considered at risk by state or federal agencies, which list them as endangered, threatened, of ‘special concern,’ or ‘sensitive’.”

Conflict:

“By comparison, 30% of the statewide fauna are so listed.”

“In total, about 60% of the state’s vertebrate fauna occurs in the Sierra Nevada to some extent. [Only] three modern vertebrate species once well distributed in the range are now extinct from the Sierra Nevada: Bell’s vireo, California condor, and grizzly bear. The grizzly bear was directly exterminated by Euro-American settlers. The California condor suffered a series of blows, including the extinction of the Pleistocene megafauna upon which it once fed, elimination of most remaining wild and later domestic grazers, indiscriminate shooting, and finally, ingestion of lead slugs and collisions with power lines. Bell’s vireo lost much of its riparian willow habitat and suffered from cowbird parasitism.” “It is most likely that the decline of vast herds of Pleistocene ungulates made condors rare by the time of European exploration.” (Note: habitat alteration by timber harvest was not a contributor to these extinctions.)

Concern:

“Riparian areas have been damaged extensively by placer mining (northern and west-central Sierra) and grazing (Sierrawide) and locally by dams, ditches, flumes, pipelines, roads, timber harvest, residential development, and recreational activities.”

Conflict:

“Altered [aquatic] habitats are often linked to successful establishment of non-native species. Historically, only about twenty high-elevation lakes contained fish, whereas there are now more than 2000 lakes containing fish. This human-mediated ecological transformation has had severe detrimental impacts on native aquatic invertebrates and amphibians, causing drastic reductions in distribution and population sizes.”

“At high elevations, introduced fish seem to be the primary cause for loss of mountain yellow-legged frog populations throughout historic ranges. Causes for the coincidental decline of amphibians at low elevation are still unknown.”

Concern:

“Generally they [the management strategies] do not attempt to specify cost or funding source.”

Conflict:

“The Fire and ALSE [areas of late successional emphasis] strategies proposes some harvest of timber and biomass. These activities will produce income but may not cover the full cost of the strategies. None of the strategies are likely to succeed unless they look beyond nearby commodity outputs to identify the full range of beneficiaries of their actions and to devise mechanisms to recover a portion of that benefit.”

CFA June 10, 1996

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