REGENERATION SILVICULTURE AS
BY THE QUINCY LIBRARY GROUP
The Quincy Library Group Bill requires utilization of group selection and individual tree selection prescriptions to achieve the desired future condition of an all-aged, multi-story, fire resistant forest as described in the Quincy Library Group Community Stability Proposal.
Group selection silviculture will be practiced on lands labeled "available for Group Selection," on the QLG Community Stability proposal map. The QLG Bill describes these lands as the "pilot project area." Silvicultural activities on these lands will be consistent with the recommendations of CASPO and the Sierra Nevada Ecosystem Project.
The proposal specifies group selection similar to that being practiced since 1976 at the Blodgett Forest Research Station of the Univ. of Calif. Berkeley.
The CASPO Technical Assessment (McKelvey et al. 1992) analyzed some potential long term strategies for timber management in the Sierra. That report addresses group selection silviculture as follows: "One kind of structure that may have promise for protection and long-term maintenance of owl habitat is multi-aged mosaics of small, even-aged groups or aggregations. Groups would generally range in size from about 2 acres down to a quarter-acre, or probably less. Probably this type of silviculture best approximates pre-settlement stand structures. This warrants serious consideration. Openings would be sufficiently large to permit regeneration of shade-intolerant as well as shade-tolerant species. Multiple size classes in general would be separated horizontally rather than vertically, but in sufficient proximity to satisfy this attribute of owl habitat. The horizontal separations of size class also would confer some degree of resistance to crown fire."
Group selection silviculture is addressed as follows, in chapter 44 of the Sierra Nevada Ecosystem Project final report to Congress (Weatherspoon 1996): "The long-term sustainability of any desired forest condition in the Sierra Nevada depends in part on adequate establishment of vegetation at suitable intervals."
According to Weatherspoon, evidence indicates that the pre-settlement fire regime which dominated most Sierra Nevada forests produced a mosaic of small even-sized groups of trees. The pre-settlement fire regime is described as one in which fire burned relatively frequently at low to moderate severity with many small trees being killed by the fire, but most large trees surviving. "Scattered individuals and groups of main canopy trees, however, are killed where the fire locally flares up or burns more severely (or groups of trees previously killed by other agents such as bark beetles are consumed to varying degrees by the fire), leaving scattered small openings with a matrix or surviving small trees." (Weatherspoon 1992)
He describes this fire regime and stand structure as common during the pre-settlement era in the Ponderosa and mixed confer forests and states: "Silviculturally this kind of stand structure is approximated with the group selection cutting method." (Weatherspoon 1992)
REGULATION OF ANNUAL CUT
The QLG proposal stipulates that group selection cutting will be regulated by area control with a 150 year rotation on Dunning sites 1 and 2, and a 200 year rotation on sites 3, 4, and 5. This means that the amount of timber cut annually will be regulated by land area rather than timber volume. The number of acres harvested annually is calculated by dividing the total acres in the pilot project area by the number of years in the rotation. Assuming that the Dunning Site classes are evenly distributed, a reasonable estimate of acres cut annually is 1/175 or 0.57 percent of the pilot project area, the amount stipulated by the QLG Bill.
All spotted owl habitat areas and protected activity centers within the pilot project area will be deferred from resource management activities as required by the Bill. The Bill also requires that all riparian areas within the pilot project area are protected by the Scientific Analysis Team Guidelines found in a Forest Service document titled Viability Assessments and Management Considerations for Species Associated with Late Successional and Old-Growth Forests of the Pacific Northwest," (Thomas et al 1993)
Third order watersheds are recommended as timber harvest units. However, it becomes impractical, as well as economically and environmentally undesirable, to harvest in every third order watershed each year. Therefore, a cutting cycle method will be used in which no cutting is done for a period of years within specific watersheds and the accumulated harvest acres are all cut in one year at the end of the cycle. Typical cutting cycles vary from about fifteen to twenty years.
SIZE OF OPENINGS
Research at Blodgett Forest has shown that group selection openings should be approximately twice the surrounding upper canopy height in width to allow establishment of tree species which are intolerant of shade (Ponderosa and Sugar Pine.) Depending on the height of surrounding trees, group openings may vary from about .25 acres to 2.5 acres. For example, if average heights of surrounding trees is 110 feet, then the opening would be about 220 feet in diameter or .87 acres. Openings smaller than 1.5 times the canopy height will show a decrease in tree growth. At the Blodgett Forest, the public reacted negatively to openings larger than about 2.5 acres (Holmen and Heald 1988.)
Group selection openings should be designed to fit the terrain, existing vegetation, fuel conditions, stand health, wildlife habitats and other ecosystem conditions.
SKID TRAILS AND LOCATION OF OPENINGS
Skid trails to accommodate removal of logs should be located near the edge of openings whenever possible and should be located with future cuts in mind. Timber should be felled into the cut area or into adjacent timber stands, not into areas previously cut containing non-sawtimber sized trees. (Holmen and Heald 1988)
The distance between group cuts should allow for creation of correctly sized group cuts in the future.
RETENTION OF LARGE TREES
Individual trees within the group may be designated to be retained. CASPO Interim Guidelines currently require the retention of trees larger than 30 inches DBH. Other trees and snags, of any size, could be designated for retention as well.
All fuels generated by timber harvesting must be treated or removed. These fuels may be chipped on site and removed for biomass fuel or ethanol production, or burned in piles or by broadcast methods depending on conditions and circumstances. Excess fuels wil be utilized whereever possible.
On slopes where machinery can operate, there are a variety of fuel management options. For long-term fire protection, fuels should be treated not only within the regeneration opening but also in the surrounding stand.
Regeneration in the openings could be natural or by planting, or by a combination of both. Removal of competing vegetation may be necessary on some sites.
MAINTENANCE OF RECORDS
In the past, a major objection to group selection has been the difficulty of keeping track of numerous small openings. New technologies of GIS and GPS will make this significantly easier. It is probably not appropriate to keep records on each individual opening. Rather, records can be maintained on management units, which is consistent with forest ecosystem management on a landscape level.
SINGLE TREE SELECTION
The QLG Bill states, "individual tree selection may also be utilized within the pilot project area."
In those situations where single tree selection is determined to be the appropriate silviculture method, the allowable cut in any planning unit should be based on annual growth. Again, cutting cycles may vary. A 20-year cutting cycle would allow the harvest of 20 years of net annual growth within a planning unit.
SELECTING TREES TO BE HARVESTED
The CASPO team has suggested to the Library Group that diameter frequency distribution curves be utilized to determine appropriate distribution of diameters in uneven-aged stands. Dr. Verner commented that "if the bumps on the curve were targeted for harvest you would not be violating CASPO.' It was suggested that this strategy could be applied to either group selection or single tree selection cuts. With group selection, naturally occurring "clumps" of trees would be marked for harvest.
Alternative strategies based on tree health rather than diameter may be more appropriate to the Quincy Library Group goals.
Listed below are several risk-rating systems, all based on crown characteristics, which could be used to select the less vigorous, higher risk trees for harvest:
1. Keen Tree Class System (See attachment A)
2. Collins Pine Crown Classification System.
3. California Pine Risk-rating System.
4. Risk-rating System for Mature Red Fir and White Fir in Northern California. (Ferrell) (See attachment B)
Regardless of silvicultural system, any regeneration-harvest operation must consider snag retention.
One reasonable approach to snag retention has been suggested by Malcolm Hunter. "Within the United States, biologists studying forest types from nearly every region of the country have arrived at recommendations for snag densities that are remarkably consistent (e.g., Scott 1978, Evans and Conner 1979, Thomas et al. 1979, Harlow and Guynn 1983, Raphael and White 1984, Zarnoqitz and Manuawal 1985, McComb et al. 1986). Furthermore, in at least one context, U.S.National Forests in the Pacific Northwest, forest managers are following the biologists' advice (Bull et al. 1986). It is not certain to what extent this concordance represents data, but until better models are derived, 5-10 large snags per hectare* seems like a reasonable target. Using this quota as a rule of thumb may be rather simple and unsophisticated, but it is preferable to deciding that the model is too complex and ending up with no snags at all." (Hunter, 1990.) *Note: 5-10 snags per hectare equals 2-4 snags per acre.
Snag requirements are currently dictated by the CASPO Interim Guidelines.
Communities within the QLG area depend on forest resources to meet many human needs. Our goal is to provide management direction which will yield commodity resources while sustaining the health and diversity of the forest ecosystem.
We believe that ecosystem based management is the appropriate approach to achieve this goal. The following description expresses this management approach: "An ecosystem approach to management focuses on the restoration and maintenance of natural processes, such as water cycling, nutrient cycling, soil formation, and vegetative succession, and the conservation of natural diversity in plant and animal life. Management decisions are based on sustaining ecosystem functions rather than on any single element or species in isolation. "An ecosystem-based management approach is not a tool, rule, or recipe for land management. Instead, it attempts to consider whole natural systems and how they function and to understand how human activities affect and are affected by them. It recognizes that we often don't fully understand how natural systems really work." (From Hart Mountain National Antelope Refuge Planning Update, August 1993.
Ferrell, George T. 1980. Risk-Rating Systems for Mature Red Fir and White Fir in Northern California. Pacific Southwest Forest and Range Experiment Station. General Technical Report PSW - 39.
Holmen, Scott P. and Heald, Robert C. II. 1988. Group Selection Silvicultural Systems, A Planning Example. Blodgett Forest Research Station. Dept. Forestry and Resource Management. University of California Berkeley, Calif.
Hunter, M.L. 1990. Wildlife, Forests, and Forestry: Principles of Managing Forests for Biological Diversity. Regents/Prentice Hall
McKelvey, Kevin S. and Weatherspoon, C. Phillip. 1992. Projected Trends in Owl Habitat. The California Spotted Owl: A Technical Assessment of its Current Status. U.S. Forest Service general technical report PSW-GTR - 133.
Weatherspoon, C. Phillip. 1996. Fire - Silviculture Relationships in Sierra Forests. Volume II Assessments and Scientific Basis for Management Options. Sierra Nevada Ecosystem Project. Final Report to Congress. Wildland Resources Center Report No. 37. Univ. of Calif. Davis.
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