Section 2: A Plan for Restoring Salmon on the Tillamook and Clatsop State Forests Using Anchor Habitat Strategies
Section 2: A Plan for Restoring Salmon on the Tillamook and Clatsop State Forests Using Anchor Habitat Strategies
Concept and selection of Anchor Habitats in the Tillamook and Clatsop state forests
Ecotrust, Oregon Trout, and the Wild Salmon Center have developed a habitat-based strategy for restoring salmon runs in the coastal Pacific Northwest region. This strategy is based on watershed-specific evaluations that identify the most productive portions of the stream for native salmonids. When combined with other management tools, the protection and restoration of these critical anchor habitats create a strategy that is both ecologically and economically viable for the watersheds of the Northwest. We propose that this strategy be implemented on the Tillamook and Clatsop State Forests.
The specific anchor habitat strategy has been largely developed by Dr. Charley Dewberry during his watershed and salmon restoration project on the Knowles Creek in the Siuslaw watershed from 1991 to present. The Knowles Creek Project is a cooperative restoration effort of the U.S. Forest Service, The Hancock Timber Resources Group, and the Pacific Rivers Council.
- If a stream can only produce a few young salmon each year, than no matter what else happens during the life cycle of the fish, they won't return in economically viable numbers.
- As the watershed habitat is degraded, salmon populations are pushed toward the headwaters of the stream. Not all parts of the landscape have equal value for salmon. These small headwater streams can't produce many salmon. Habitat is limited, they are more susceptible to landslide and debris, and they are not the most productive part of the watershed. This is particularly true for coho.
- Salmon populations that can't move upstream become restricted to limited areas of the basin. This is particularly true for chum and chinook. As the distribution shrinks, each area that continues to support salmon becomes increasingly vital to their survival.
- Given that many salmon species in the Tillamook and Clatsop region are at five percent or less of their historic abundance, protecting the areas that continue to support juvenile salmon is critical to their persistence in the basin. We must protect the dwindling areas where salmon reproduce.
- Restoring downstream productivity is critical to salmon recovery. Historically, the lower portions of the streams were the most productive. If state salmon recovery objectives of achieving economically viable numbers are to be met, these areas must begin producing salmon again.
- Recovery of the lowland areas downstream starts upstream. If upstream reaches are in poor condition, the cumulative effects will be felt downstream. So recovery has to start upstream.
The Salmon Anchor Habitat Strategy focuses on restoring key watershed processes — especially the movement of sediment and organic matter through the watershed. These processes are vital in providing salmon with the food, spawning materials, and shelter. The strategy initially identifies the portions of the watershed that must be protected to maintain critical watershed functions.
The first step is to determine the distribution and abundance of each salmon species in the basin. Because damaged watersheds restrict salmon to particular areas, determining where the salmon are becomes crucial. Not all portions of the basin are equal. The most critical reaches are those being used by salmon for spawning and rearing, as well as the areas immediately upstream.
The first pass at determining distribution and abundance of salmon was done by reviewing existing information and by conducting a systematic snorkel count of juvenile salmon throughout most of the Tillamook and Clatsop region.
Existing information was gathered from Oregon resource management agencies. In Oregon this consists of Oregon Department of Fish and Wildlife (ODFW) spawning surveys as well as some core area maps. Surprisingly little information was available on where juvenile salmon have been found in the region. Also, existing information was difficult to use for ranking areas by their importance to salmon production.
To rectify this lack of information, stream ecologist Charlie Dewberry personally went into the streams themselves and conducted a systematic stream survey during the summer of 1999 and 2000. Because all snorkeling was done by a single diver, a very systematic technique was used.
This method provided a quick snapshot of juvenile salmon distribution and abundance over a wide area. It works best for coho salmon -that tend to cluster-but also provided valuable information regarding the use of these watersheds by juvenile chum, chinook, steelhead and cutthroat trout.
Management within anchor habitat areas is aimed at restoring watershed function, old-growth characteristics on the uplands, and recovering more natural sediment and organic matter movement in the watershed. Forest management in an anchor habitat is limited to activities that speed recovery. Upland management is targeted to reduce erosion in the anchor habitat. Roads should be evaluated and those not needed decommissioned. Road crossing and culverts should be upgraded to handle 100-year storm events without failing.
Restricted activities on steep, unstable slopes
We suggest that on uplands outside the anchor habitat, no land use actions should be allowed on steep unstable slopes that would greatly increase the size and frequency of landslides and erosion. Here too, roads and stream crossings should be upgraded to handle a 100 year storm event and landslides should be restricted to a more natural level of occurrence and magnitude. These areas contribute a considerable proportion, if not the majority, of large wood for the stream system.
Riparian zone management areas
Recovery of riparian zones is recognized by virtually everyone as a key element of salmon recovery. Riparian zones influence processes such as flood routing, sediment trapping, nutrient update, organic matter inputs, shade, stream temperatures and root strength. We focus on the movement of sediment and organic matter through the basin. The other functions will follow.
The riparian area of the forest is important in controlling erosion. A healthy riparian forest can stop large landslides, debris torrents and flows and dam-break-debris floods that are particularly destructive to salmonid populations.
On the uplands, only the primary channel of the drainage network will have a 100 foot restricted riparian management zone where activity will be limited to restoration efforts.
Larger streams will have a restricted zone defined by the valley floor and the first 100 feet up adjacent hill slopes. Within this restricted area, management objectives are for old-growth characteristics. Past 100 feet, harvest will be limited to half the area. No timber harvest will be allowed at tributary junctions and other measures will be taken in highly unstable areas to avoid mass erosion.
Using this approach, the selected habitats will anchor the most critical areas of the basin. Without this key step, activities will likely result in increased mass erosion which could lead to the loss of highly productive salmon areas. Areas outside anchor habitats are managed in a way to avoid setting off landslides. Riparian areas are managed to begin the process of restoring the stream and valley floor's ability to capture and hold sediment and organic matter.
Anchor habitats and salmon stocks identified for the Tillamook and Clatsop state forests
Plympton Creek: from the mouth
(steelhead, coho, and cutthroat trout)
South Fork Klatskanine River: above agriculture lands
(steelhead, coho, chinook, and cutthroat trout)
(coho, steelhead, and cutthroat trout)
Necanicum Watershed: above Hwy 26 bridge
(coho, steelhead, and cutthroat trout)
- Nehalem, North Fork
- Coal Creek (coho, steelhead, chum and cutthroat trout)
- Soapstone Creek (coho, steelhead, chinook, and cutthroat trout)
- Below Hamlet reach (coho, steelhead, and cutthroat trout)
- God's Valley Creek (coho, steelhead, and cutthroat trout)
- Fishhawk Creek (coho, steelhead and cutthroat trout)
- Humbug Creek (coho, chinook, steelhead, and cutthroat trout)
- Lost Creek (coho, steelhead, and cutthroat trout)
- Rock Creek above Fall Creek (coho, steelhead, and cutthroat trout)
- Wolf Creek, North and South Fork (coho, steelhead, and cutthroat trout)
- Lousignant (coho, steelhead, and cutthroat trout
- Foley Creek East Fork (coho, steelhead and cutthroat trout)
- Cronin Creek (chinook, coho, steelhead, and cutthroat trout)
- Wilson River, Little North Fork (coho, chinook, chum, steelhead, and cutthroat trout)
- Kilchis River, North Fork: above and including Shroader Creek (coho, steelhead, and cutthroat trout)
- Kilchis River, Little South Fork (coho, chinook, chum, steelhead, and cutthroat trout)
- Miami River: all on state land (chum, coho, steelhead, chinook and cutthroat trout)
|Allocation of Acreage in the Anchor Habitat Strategy|
|State Forests (T&C)||492,000 (approx)||100%|
|Anchor Habitats for Salmon||87,099||17.9%|
Clear Creek, upper (coho, chinook, steelhead, and cutthroat trout)
Timber management options within an anchor habitat strategy
The forest management prescriptions for the anchor habitat strategy treat both the two major landscape elements of watersheds: riparian zones and upland slopes.
The elements of forest management that we describe here include:
- Steep slope restoration practices
- Thinning in upland stands
- Riparian condition and restoration management
This framework balances what is known about watershed level process with scientific uncertainty and economic interests. It attempts to provide an effective, efficient framework of forest practices to recover salmon populations. Appendix 1 summarizes and compares the overall management approach
Restrictions on steep slopes is the key factor of the forest management strategy in the anchor habitat approach. Steep slope protection is key to ecological functioning of watersheds. An anchor habitat strategy relies on the delivery of large wood to the riparian zone.
We propose that no timber harvesting occur on steep slopes, except very limited removals (see Table 1) to hasten the establishment of older forest characteristics. Steep slopes are identified by the application of the GIS-based shallow landslide model (SHALSTAB) from Montgomery and Dietrich (1994). A significant portion of these slopes occur inside the proposed anchor habitats.
Riparian and upland thinning
|Table 1: Proposed Silvicultural Thinning Guidelines Anchor Habitat Strategy Tillamook and Clatsop State Forests|
|Pioneer||Early Seral||Mid-seral||Late Seral|
|Uplands in anchor habitats (not riparian or unstable slopes)||PCT annual maintenance||6,000–7,000 bf/acre Commercial thin — leave 20%||First or second commercial thin approximately 15,000 bf/acre — leave 20%||thin approximately 18,000 bf/acre leave 20% Future removals approx 20,000 bf/acre leaving 20%|
|Unstable slopes||PCT annual maintenance||5,000 bf/acre- leave 25%||First or second commercial thin 5,000 bf/acre — leave 50%||10,000 bf/acre — leave 75%|
|Riparian and valley floors inside anchor habitats||mgmt of inner zone (100 ft) aquatic purposes only, no removal of material PCT and annual maintenance||mgmt of inner zone (100 ft) aquatic purposes only, no removal of material PCT and annual maintenance outer zone- commercial thinning 5,000 bf - leave 50%||mgmt of inner zone (100 ft) aquatic purposes only, no removal of material PCT and annual maintenance outer zone- commercial thinning 6,000–7,000 bf||mgmt of inner zone (100 ft) aquatic purposes only, no removal of material PCT and annual maintenance outer zone- commercial thinning 8,000 bf leave 50%* leave largest trees until riparian objectives are met Addition harvest of outer zone commercial thin maintaining riparian objectives - leaving 50%|
|Riparian zones outside of anchor habitats||mgmt of inner 100 feet — aquatic purposes only, no removal of material PCT and annual maintenance||outer zone — thinning allowed 5,000 bf/acre leave 25%||outer zone — thinning allowed 7,000 bf/acre leave 25% must meet riparian objectives||outer zone — thinning allowed 10,000 bf/acre leave 25% must meet riparian objectives|
On uplands that are not steep the management goal within anchor habitats is to recover watershed function and old growth forest characteristics. We use the definition as provided by the Late Successional Reserves Panel (USDA,1994) for the Coast Range. These definitions are provided in Appendix 2.
To facilitate the recovery of this forest condition, a maximum of 3 thinning treatments are prescribed within a 100–120-year period. Table 1 lists the specific details of the thinning regime by forest condition and landscape type.
In general terms, thinnings generate harvested volumes of 5 to 20 mbf per acre over the long rotation period of 100–120 years. 20–75% of the trees will remain after the thinnings depending on the combination of forest conditions and locations within the watershed.
Importance of linked upslope and riparian zone processes
Recovery of riparian zones is almost universally recognized as a key element of salmon recovery. Riparian zones influence a number of processes such as flood routing, sediment trapping, nutrient uptake, organic matter inputs, shade, stream temperature, and root strength (Gregory et al., 1991; Gregory and Bisson, 1997). For our purposes the primary focus of riparian management is on control of sediment and organic matter movement within the basin. Other riparian functions will naturally follow from this key watershed process (Dewberry, 1998).
The riparian forest exerts considerable control on mass erosion within the basin. A healthy riparian forest can stop large landslides, debris torrents/flows, and dam-break-debris-floods (e.g. Dewberry et al. 1998, Dewberry et al. 1999). Dam-break-floods are particularly destructive to salmonid populations.
The riparian prescriptions were set by focusing on the critical role of the riparian forest in the dynamics of sediment and organic matter within the basin. No timber harvest is allowed on debris torrent fans in the riparian zone (mostly at tributary junctions). The only management activities allowed on debris torrent fans are activities to recover old-growth characteristics. If the toe slopes are active, then enough trees must be left so that erosion rates are not sharply increased.
Under our framework, the key ephemeral channels in the anchor habitats receive complete protection. In intact basins the amount of large wood which moves down tributaries into the mainstems can be up to 45% of total wood in the system (McGarry, 1994). The primary ephemeral channels, which deliver material straight into downstream channels are given some protection, while the other ephemeral channels only receive some protection from the restrictions to steep unstable slopes. These later ephemeral channels usually enter downstream channels at or near right angles and the material moving in the debris torrent/flow is often stopped in the tributary junction. Further downstream all fans which are in the basin are protected. Permanent channels receive considerable attention in this framework reflecting their critical role within the watershed.
When the anchor habitats, restricted steep, unstable slopes, and the riparian management areas are linked to form a forest practices framework, an effective, efficient restoration strategy emerges. The anchor habitats "anchor" the areas in the basin which are the most critical. Without these protections, activities will likely result in increased mass erosion and the subsequent loss of highly productive salmon habitat. This would set back restoration dramatically. Outside the anchor habitat areas, steep unstable slopes, where landslides and debris torrents/flows are initiated, would become important tools — as restricted areas — for restoration. Meanwhile, the riparian management areas begin the process of restoring the stream and valley floor's ability to capture and hold sediment and organic matter moving in debris torrents or dam-break-floods (Dewberry et al. 1998, Dewberry et al. 1999).