Assessment

* Logging in the Sierra Nevada

MANAGEMENT STRATEGIES

* Implementing SNEP Forest Strategies

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Strategy 1. Areas of Late Successional Emphasis

The SNEP team developed one forest condition strategy, areas of late successional emphasis (ALSEs), in considerable detail, advancing new simulation models, developing multiple alternatives based on different starting points, and evaluating implications from various runs. These are described in detail in technical reports found in volumes II and III and the addendum to the SNEP final report. Only a brief summary is presented here. This strategy has been developed primarily for west-slope forests, specifically mixed conifer and red fir/white fir types, although in principle the design could apply to several other Sierran forest types. The strategy is targeted for public forest lands, but it could be adopted on private lands where conditions and goals permit.
This strategy stratifies forestland into two landscape categories: areas of late successional emphasis and matrix lands. Achievement of goals at the rangewide scale depends on an integrated network of ALSEs and managed matrix lands across the latitudinal and elevational distribution of the forest type. Different management applies, or is allowed, in ALSEs and matrix lands.

Possible Solutions

Areas of late successional emphasis are areas with a management emphasis on maintenance of structurally diverse forests that provide high levels of late successional function, including habitat for species requiring or preferring such conditions. ALSEs would be large landscape units, typically in the range of 20,00060,000 acres (multi-polygons), distributed across the range of the forest types. Existing high-ranked polygons (4s and 5s) would be used as starting points for identifying ALSEs, with adjacent or intermixed polygons potential areas for enhancing late successional characteristics. It should be recalled that these areas would not be homogeneous continuous stands of old trees. Patches of lower-ranked stands are included in many 4 and 5 polygons; what is more important, as described earlier, the natural late successional condition of Sierran middle-elevation forests is defined by great spatial variability (patches of deep forest interspersed with treefall gaps, areas where fires burned at different intensities resulting in different densities, etc.).
The size of ALSEs and their distribution are based on several criteria. Large size (multi-polygon) is promoted for ecological reasons: large blocks are assumed to provide preferred habitat over small areas for some plants and animals. Large areas also allow better opportunity to protect against loss from catastrophic fire (fuel breaks, fuel reduction) than small areas; if, however, fire should be uncontainable within ALSEs, they are unlikely to be entirely consumed. ALSEs are distributed across the elevational and latitudinal range of the forest types in the western Sierra. Gaps in ALSE distribution at the rangewide scale would occur where large blocks of high-ranking stands do not at present exist to form the base of an ALSE network, or where intermixed land-ownership patterns and conflicting land-use objectives preclude development of large areas.
Management of ALSEs would emphasize treatments to maintain, enhance, and protect high-quality late successional conditions . Active management within ALSEs is anticipated in at least some areas, with prescribed fire being the primary tool. Mechanical fuel treatment (timber harvest) could be allowed if limited in intensity and extent so as to maintain conditions as near natural as possible.
Fire protection within and adjacent to ALSEs would be priority ranked for treatment depending on fire risk severity. Adjacent areas would be subject to active management, with treatments including fuels breaks and other fuel protection zones, timber harvests, and prescribed burning.
SNEP developed several ALSE configurations. One solution is illustrated in plate 6.3. If the ALSEs depicted here were actually grown out as indicated, they would about double the present amount of late successional forest. The exact areal extent of high-quality late successional forest ultimately needed to achieve the objectives cannot be determined from existing information. However, the design and approximate overall abundance of late successional forests are most important. Extent and location of ALSEs illustrated here provide one solution. Local conditions will present real constraints and opportunities. However, the current total acreage is far below levels that existed in the pre-contact landscape, outside what is believed to be the natural range of variability if the rough benchmark of the national parks can be used, and may be inadequately distributed to support plant and biodiversity needs or to be protected against catastrophic loss.
ALSEs as described would not be adequate to sustain amounts or distribution of late successional forest near pre-contact levels; contribution of other forest lands is essential to a rangewide network. Matrix lands are forested areas outside of ALSEs and fuel protection zones, and they would typically have primary management objectives other than attaining late successional representation. These may be multiple-use forest lands: timber, recreation, firewood cutting, and so on. Although matrix lands have other primary objectives (e.g., wood production), restoration of late successional forest conditions in structurally simplified stands to the structural standards of rank 3 will be critical to achieving adequate amounts of late successional forest at the rangewide scale. Forests have undergone significant structural simplification as a result of timber harvest and other human-caused disturbance. Higher levels of structural complexity are needed in the matrix to maintain biodiversity and forest functions in managed stands that are more characteristic of natural forests. Some of these processes and speciessuch as the array of fungi that form mycorrhizae with treesare of direct importance in maintaining the long-term productivity of these sites. Greater structural diversity may also be important to improve the degree of connectionwhich affects movement of organisms and materialsacross the managed landscape.