Interagency Clearinghouse of Ecological Information

Amendment to Blue River Landscape Management Strategy

Addendum #1

July 27, 1999

Subject: Intermediate timber harvests


The initial Blue River Landscape Management Strategy (4/18/97) was developed with a focus on regeneration harvests using fire history as a general model. The subject of intermediate harvests; i.e., precommercial and commercial thinnings was not addressed in the initial strategy. References in the 4/18/97 document to timber harvests were intended to apply to regeneration harvests, as explicitly described in the strategy.

Proposals for commercial thinning are now being considered for the Blue River watershed. A variety of situations exist: natural stands, plantations, in subwatersheds where regeneration harvests will be occurring in the next 40 years (1995-2035), in subwatersheds expected to serve as refugia for the next 40 years but are scheduled for harvest in future decades, and in reserves. Clarification of the intent of the Blue River landscape management strategy with respect to intermediate treatments is needed.

Landscape Management Strategy

Special Area Reserves

No modification needed; direction in the Willamette National Forest plan (1990, as amended by the Northwest Forest Plan 1994) is appropriate for intermediate treatments.

Landscape Areas

Landscape areas are where most questions arise. These are the zones where timber harvest is scheduled. Landscape areas are intended to provide late-successional habitat and timber production while meeting aquatic ecosystem objectives. Intermediate stand treatments (pre-commercial and commercial thinnings) can accelerate development of older forest structures while providing some economic benefits. Where intermediate treatments are planned, prescriptions should be established using the landscape block scheduling and general prescriptions of the landscape management strategy. Each of the situations described above are addressed below.

Subwatersheds scheduled for harvest in the first 40 years (1995-2035)

Although the focus of the 4/18/97 strategy was on regeneration harvests, it was assumed that precommercial and commercial thinning would occur in plantations following regeneration harvest. Table 2 (4/18/97) explicitly lists guidelines for precommercial and commercial thinning. These guidelines were meant as initial assumptions to be refined by subsequent modeling and analysis, and by operational experience. Two modeling projects are currently underway with results expected by the end of 1999. Thinning guidelines should be revisited when these studies are complete.

Intermediate treatments in existing plantations are also appropriate and desired to maintain stand growth, develop large trees, and promote understory diversity. These treatments should be synchronized with the timber harvest schedule for the landscape block the plantation sits within. If regeneration harvest of the block is scheduled for 80 or more years in the future, thinning activities should emphasize development of old forest structures.

Thinning of young natural stands may also be appropriate for the same reasons listed above. These stands may already provide some old forest habitat values. Thinning decisions should carefully consider existing stand conditions at the site scale and the habitat values provided.

Subwatersheds not scheduled for harvest in the first 40 years – refugia

These areas are intended to serve as refugia "so that organisms can repopulate areas impacted by natural or human-initiated disturbances" (4/18/97, p. 21). However, these areas are also intended for long-term timber harvest and intermediate treatments may be appropriate for the same reasons stated above. However, refugia objectives for these areas impose additional considerations. These areas are intended to provide late-successional habitat during the first 40 years (1995-2035). Intermediate treatments that reduce late-successional habitat during this period are not generally desired. An additional objective is to limit the period of time these areas are subject to management disturbance. The intent is to group management activities in time so that relatively long undisturbed periods can occur in the refugia. This may mean that the timing of thinning activities is less than optimal from a stand growth or economic perspective. In addition, road closure and restoration is a primary objective in these areas. Access for intermediate treatments needs to be integrated with road restoration and management strategies. An integrated restoration strategy, including a schedule of specific activities for the first 40 years, should be developed for the Cook-Quentin subwatersheds by 6/1/2000.

Aquatic reserves

Aquatic reserves were meant "to ensure that aquatic habitats and processes are protected", and should "provide contiguous blocks of undisturbed habitat" (4/18/97. P. 19). Timber production is not an objective for these reserves. Intermediate treatments are not generally desired in aquatic reserves. However, some reserves contain portions of plantations within them. Thinnings may be appropriate in plantations specifically for the objective of restoring habitat for the long term.

Timber harvest scheduling – refugia watersheds

This section is amended to clarify that the language on p. 26 was intended to apply to regeneration harvests only. The intent for intermediate treatments is expressed in the paragraphs above.