SILVICULTURE, TIMBER MANAGEMENT and
THE DESIRED FUTURE CONDITION

by Michael Yost (5/24/94)

Desired Future Condition

The Quincy Library Group has described the desired future condition as: "all age, multi-story fire-resistant forest approximating pre-settlement conditions". The best data available on pre-settlement conditions relative to stand structure come from Sudworth's plots as reported in CASPO. (McKelvey, K., and James D. Johnston, 1992, The California Spotted Owl: A Technical Assessment of its Current Status, P. S. W. USFS.) (See Attachment B.)

The Desired Future Condition should also include a description of functions as well as structure. I would suggest adding the following statement from the CASPO Report: "We wish to create a forest in which natural processes are fully functional and stable" (McKelvey, K., and C. P. Weatherspoon, 1992, The California Spotted Owl: A Technical Assessment of Its Current Status, P. S. W. USFS.)

The silvicultural strategies recommended by the Library Group to achieve this condition are intermediate thinning and regeneration harvest using group selection and single tree selection. It has been recommended that the Quincy Library Group develop a Desired Future Condition and appropriate silvicultural strategy for each major forest type within the three Forests; i. e., true fir, mixed conifer, and eastside pine.

Intermediate Thinning Intermediate cuts will mostly be thinnings from below. Forest health is the primary objective. Fires hazard, risk of insect and disease, over-stocking and overstory suppression are some characteristics considered when selecting trees to cut. Trees removed during thinning operations will generally be in the smaller diameter classes.

Thinning should be structured to achieve stocking levels with the desired species composition and individual phenotypes to grow these areas into future groups. Where feasible, slash should be chipped or burned following thinning operations and a prescribed fire underburn should be considered. Planning watersheds are the appropriate landscape element for intermediate thinnings. Third order watersheds would be the most common size.

Regeneration Harvest

All Regeneration or harvest cuts should be preceded by a long range plan for the watershed which would include some type of thinning operation as described under the above section on Intermediate Cuts.

The desired future condition, stand structure objectives, wildlife needs, and other resource objectives must also be considered. Silvicultural strategies include group selection and single tree selection.

Group Selection

Group selection is the primary silvicultural method recommended by the Quincy Library Group. Group selection cuts will be regulated by area control, with third order watersheds as the recommended planning units. A 150-year rotation is recommended for Dunning Sites 1 and 2, and a 200-year rotation is recommended for Dunning Sites 3-5.

This means that in a planning unit where the average site is 1 or 2, 1/150 of the acres could be harvested in any one year. However, because of the impracticality of harvesting in each unit annually, group selection normally employs the cutting cycle concept where no harvesting is done for a period of years and then the accumulated harvest acres are all cut in one year at the end of the cycle.

For example, a 20 year cutting cycle would allow 13 percent of the area unit within a Site 1 or 2 planning unit to be harvested every 20 years, or 10 percent of the unit if the site were 3-5. Cutting cycles may vary to allow for flexibility with harvest schedules, and planning units where both site class categories are represented would be broken down into sub-planning units for timber harvest.

Single Tree Selection

In those situations where tree selection is determined to be the appropriate silviculture method, the allowable cut in any planning unit must be based on annual growth within the unit. 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.

Selection 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 Figure 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)

Snag Retention

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. 1979c, Harlow and Guynn 1983, Raphael and White 1984, Zarnowitz and Manuawal 1985, McComb et al, 1986a). Furthermore, in at least one context, U. S. National Forests in the Pacific Northwest, forest managers are following the biologists' advise (Bull et al, 1986). It is not certain to what extent this concordance represents independent arrivals at an ecological "truth", especially since it is all based on North American 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 is preferable to deciding that the model is too complex and ending up with no snags at all."

Hunter, M. L. 1990. Wildlife Forests, and Forestry: Principles of managing Forests for Biological Diversity. Regents/Prentice Hall.

*Note: 5-10 snags per hectare equals 2-4 snags per acre

ATTACHMENT A

Graphic not available at this time.

ATTACHMENT B

Graphic not available at this time.

The graphs below are from The California Spotted Owl: A Technical Assessment of Its Current Status, (Verner, Jared; McKelvey, Kevin S.; Noon, Barry R.; Gutierrez, R. J.; Gordon, I., Jr.; Beck. Thomas W., Technical Coordinators. 1992. Albany CA: Pacific Southwest Research Station, Forest Service, U. S. Department of Agriculture; 285 p.

WHAT IS ECOSYSTEM MANAGEMENT?

From Hart Mountain National Antelope Refuge Planning Update, August 1993.

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 recognized that we often don't fully understand how natural systems really work.