Zones of Agreement for the restoration and management of riparian areas on the Ochoco National Forest.
Riparian areas are the interface between land and water and can be defined as zones where there is direct interaction between aquatic and terrestrial ecosystems (Gregory et al. 1991). In dry climates, such as the Ochoco National Forest (ONF), they are exceptionally productive and diverse compared to surrounding forests and rangelands (Gregory et al. 1991). Healthy riparian areas provide an array of functions to ecosystems and services to human communities including water quantity and quality, wildlife and aquatic habitat, erosion control, flood water retention, groundwater recharge, and biodiversity (Dwire et al. 2016). The riparian areas of the ONF are also critical to the economic health of surrounding communities, providing water for irrigation, forage and water for livestock, and recreational opportunities that support local businesses.
The Ochoco Forest Restoration Collaborative (OFRC) is particularly concerned with the health and function of riparian areas because of these important ecological, economic, and cultural values. We also recognize that riparian areas have been greatly altered from their naturally resilient conditions and attempt here to provide recommendations which directly address the factors influencing riparian zones in the ONF.
This document describes:
1) the collaborative’s understanding of historic and current conditions of riparian areas on the Ochoco National Forest,
2) the collaborative’s zones of agreement regarding the desired future condition of riparian areas, and
3) the collaborative agrees that best management practices are appropriate to restore riparian health and function.
Given our membership composition, collaborative mission, and historic scope of work, OFRC’s Zones of Agreements have historically focused on vegetation management. In this document, we integrate other aspects of forest management activities, including recreation, roads, historic structures and in-stream aquatic management as it pertains to vegetation management of riparian zones. Our interest is in holistic restoration of forest health and resiliency processes where a suite of restoration and management activities interface with riparian zone management.
As the ONF lies within the Blue Mountains Ecoregion, our final recommendations have been modified from the Blue Mountain Forest Partners Collaborative Riparian Zones of Agreement with omission of details specific to that geography and amended with details specific to the ONF.
Historic and Current Conditions
Our knowledge of the early historical conditions of riparian areas on the ONF is based on documentation from early European trappers and settlers, dendrochronology, geomorphic evidence and scientific literature.
These data paint a picture of riparian areas on the ONF that have changed dramatically from their historical condition. Streams on the Ochoco historically supported robust populations of Steelhead, Chinook Salmon, Bull Trout, and Redband Trout (Whitman 2002). Upland forests bordering streams were more open, maintained at low densities through frequent fires, often intentionally set by Native Americans to manage for desired species, increase wildlife forage, and ease of travel (Robbins & Wolf 1994). Diverse plant communities lined riparian corridors including willow, cottonwood, aspen, alder, birch, numerous shrub species and native forb, sedge, rush and bunchgrass assemblages (Whitman 2002). Descriptions by early Europeans indicate willows and other woody riparian species were prevalent and widespread (McAllister 2008). Wetland and wet meadow systems were also prevalent throughout many reaches, maintained by shallow water tables, frequent fire and beaver.
Beaver, which rely on riparian plants, were predominant ecological “engineers”, slowing water and promoting meadow and wetland systems by killing trees, building dams, intensively foraging and creating side channels (Naiman et al. 1998). The Crooked River was described as “exceptional” beaver habitat by Peter Skene Ogden in 1825 and early stockmen described wet meadows with abundant forage as common in low gradient valleys. Fur trappers were the first Europeans to widely affect the riparian zones in the Ochocos. Peter Skene Ogden led several trapping parties that worked with particular expedience, executing a policy by the British Hudson Bay company to create a “fur desert” south of the Columbia River to discourage American movement into Oregon. The Beaver populations in the Crooked River basin had been largely extirpated by 1847 (McAllister 2008).
Livestock grazing began in the 1870’s once the Indian Wars ended and the Ochocos were opened to settlement (Whitman 2002). Grazing was intensive and unregulated, except by local vigilantism, from 1870 to 1906 when the Blue Mountains Forest Reserve was established under the jurisdiction of the newly formed Forest Service (Hodgson 1919). Grazing was then a permitted activity but was allowed at twice the current stocking levels or more until the middle of the twentieth century (Walter & Boehme 2009). This took a heavy toll on riparian vegetation and thus interrupted sediment retention and stream bank building and maintenance (Dwire et al. 2016). Thus, by the turn of the century the combination of beaver removal and intensive grazing left many streams vulnerable to incision.11 Once stream channels deepened from this erosion, water tables dropped, and their disconnected floodplains were invaded by drought tolerant species; sage and juniper at lower elevations and conifers in forested areas (Buckley 1993).
Stream channelization and road building also had a large effect on riparian areas in the Ochocos. Many forest roads are built in or near streams requiring that streams be channelized to avoid damage to the road (Svejcar 1997). Many reaches upstream of Prineville were straightened in response to the 1964 flood to avoid flooding by moving water off the landscape faster (Whitman 2002, Svejcar 1997). During this same period many projects on the forest removed large wood and straightened channels during timber sales. Roads also concentrate overland flow, moving water into streams more quickly and increasing the risk of erosion. These actions increased peak flows which led to further erosion and downcutting.
Fire exclusion has impacted riparian areas similar to its impact on adjacent uplands. Extensive scientific research has shown that historically the dry forests in the Ochocos experienced frequent fires with a median interval from 16 to 25 years (Heyerdahl et al. 2019). Exclusion of low severity fire over the last century has led to the development of dramatically denser forests with increased abundance of shade tolerant trees (Merschel et al. 2014). Studies in the Blue Mountains have found that fires rarely stopped at the edge of riparian areas. Rather, they typically, although not always, burned right through the riparian area (Harley et al. 2020). The low degree of difference between riparian and upland fire regimes is determined by the similarity in the vegetation, physical environment, and topography of the riparian and upland areas (Dwire et al. 2016).
In the early 1990’s in response to the decline in native salmon and trout in the Pacific Northwest, partly driven by management on federal lands, the Forest Service and BLM adopted the PACFISH and INFISH strategies (Salwasser et al. 1995). These strategies established riparian habitat conservation areas (RHCAs) around streams where riparian and aquatic health would be the primary management emphasis (Roper et al. 2019). These strategies also set riparian management objectives (RMOs) for stream attributes like water temperature, pool frequency, bank stability, etc. as benchmarks for suitable habitat. Subsequent research has questioned the use of static RMOs across diverse vegetation and geological settings to judge effects of management (Kerschner & Roper 2010). A study of 136 reference and 590 managed reaches found no reaches that met all RMOs and that approximately the same percentage of reference and managed sites failed to meet PACFISH/ INFISH RMOs (Kerschner & Roper 2010). This indicates the need to set RMOs based on closely comparable reference sites to ensure differences are driven by management.
This outline of historical and contemporary activities encompasses five factors below that currently affect riparian zones in the ONF, of which are the focus of our recommendations for the restoration and management of riparian areas towards desired future conditions.
Changes in fire regimes and plant communities – historic frequency of fire in riparian zones of the Ochocos align with upland fire regimes and facilitated hardwood communities unique to both ephemeral and perennial streams (Heyerdahl et a. 2019). With fire suppression, conifer encroachment has led to a commensurate decline in hardwood abundance and diversity (Merschel et al. 2014), with pervasive effects on riparian and in-stream ecosystem function. Further, higher abundance of conifers corresponds with lower snow retention due to greater canopy interception, higher evapotranspiration rates, and likely lower base flows (Grant et al. 2013).
Impacts of native and domestic ungulates – historical grazing contributed to the decline in hardwood communities and erosion within riparian zones, where both domestic and native ungulates congregate for high-quality forage, water, and cover (Averett et al. 2017). Contemporary grazing practices seek to reduce domestic ungulate impacts to riparian vegetation, but restoration of degraded stream reaches is unlikely without excluding both domestic and native ungulates, of which compounding foraging strategies likely contribute to a lack of vegetation recovery (Averett et al. 2019; Opperman & Merenlender 2000).
Physical manipulation – historical manipulation of stream systems altered riverine-floodplain connectivity and subsurface hydrology, including the straightening of streams and subsequent high flow-incision feedbacks, road systems and berms altering downstream flows, and drainage of wetlands for grazing (Svejcar et al. 1997). These alterations also contribute to the degradation of riparian plant communities, resulting in higher peak flows, drying of riparian zones and loss of hardwood and wetland plants.
Coarse Wood Removal – The importance of coarse wood (i.e., dead-downed trees) and its control on stream channel morphology, sediment and organic matter storage and routing, and its role in the creation of fish habitat has been well established (Bjorn and Reiser 1991, Roni et al. 2014, Wohl et al. 2017a, Wohl et al. 2017b, Wohl et al. 2019). Past management actions such as the removal of large wood from streams, channelization, and road building within the riparian corridor have had negative impacts on the stream network within the project area. The net effect of direct and indirect large wooden debris and beaver removal from river corridors has increased channel conveyance for water and sediment and decreased the physical complexity of channels and floodplains (Wohl and Scott 2017).
Beaver – once widespread throughout the Ochocos, beaver modified riparian habitats via felling of trees, foraging of hardwood and herbaceous vegetation, den construction and damming of streams, all of which contributed to diverse riparian/wetland complexes. In addition to aforementioned factors, the removal of beaver from the Ochocos contributed to the simplification and incision of stream channels, resulting in further loss of critical riparian hardwood vegetation and in-stream habitat (Naiman et al. 1988).
Climate change – climate projections indicate a shift in precipitation from snow to rain, altering the seasonality and flow of water downstream (Heyerdahl et al. 2019). The current drought experienced throughout the ONF is indicative of shifts already occurring in the system, resulting in less water delivery downstream and likely interacting with high conifer density to reduce stream base flows (Heyerdahl et al. 2019). More frequent rain on snow events is also likely to lead to higher peak flows, with feedbacks resulting in greater erosion and incision of streams.
Desired future conditions
OFRC outlines the following future desired conditions for Riparian areas based on these major factors. Many of these desired conditions are adapted from the Watershed Condition Framework.
High Biotic Integrity
Riparian areas are resistant and resilient to natural disturbance and recover rapidly from human disturbances.
- Vegetation within RHCAs is resistant and resilient to the anticipated future fire regime.
- Where riparian areas are embedded in frequent fire landscapes that are dominated by upland vegetation (rather than riparian obligate vegetation) the upland vegetation is at a density that promotes low severity fire.
- Low likelihood of losing defining ecosystem components because of the presence or absence of fire.
- Vegetation is resilient to insect and disease disturbance.
- Large wood sources are available where appropriate, and contribute to soil productivity, pool creation, riparian and in-stream habitat, and reduced runoff.
Appropriate Plant Communities
Riparian areas are composed of a diversity of native vegetation adapted to riparian conditions of the ONF.
- Over 80% of the riparian/wetland areas are dominated by native mid- to late-seral vegetation that is appropriate to the site’s potential. These plant communities are vigorous, healthy, and diverse in age, structure, cover, and composition.
- Native riparian obligate hardwood and herbaceous plant communities adapted to moist soil conditions occupy most of their site potential and are reproducing sufficiently to ensure sustainability.
- Vegetation is in a dynamic equilibrium appropriate to the stream or wetland system.
- Where riparian areas are too dry to support hydrophilic vegetation, it should match the surrounding area.
Riparian areas exhibit a high degree of connectivity longitudinally along the stream, laterally across the floodplain and valley bottom, and vertically between surface and subsurface flows:
- Streams are not incised and are connected to their floodplain
- Water is not confined to artificial channels.
- Riparian conditions allow for infiltration and ground water recharge.
Historic and future engineered features do not impede restoration activities and ecological functioning of riparian areas.
- When created, human-built features/human constructions are intentionally designed to enable natural processes, mitigate unavoidable impacts to riparian areas, and limit erosion and incision.
- Access to water by wildlife is not restricted.
- Movement of wildlife, including mammals, insects, amphibians, and birds, between the riparian area and the surrounding landscape is not restricted by human constructs.
- Vertical connectivity between surface and subsurface flows is not harmed.
Riparian areas provide important ecosystem services to Central Oregon communities, including:
- High quality water for drinking
- Healthy food webs that support fishing opportunities
- Aesthetic values and places to camp, picnic, birdwatch, hike, or ride
- Flood control
- Recharge of streams and aquifers from which people draw irrigation and drinking water
Recommendations for Riparian Areas
Based on factors that have led to current degraded conditions of RHCAs throughout the ONF, we provide the following recommendations to the ONF for the restoration and management of RHCAs to promote the above desired future conditions. The following recommendations are modified from the Blue Mountain Forest Partners Riparian Zones of Agreement.
1. WHOLE WATERSHED APPROACH
As it does with the placement and arrangement of terrestrial restoration activities, the Forest Service should evaluate planning areas for restoration opportunities based on the “biggest bang for the buck,” as well as “the greatest good” for multiple resources and should seek to maximize the impact of restoration treatments. This is especially true if limited dollars for restoration activities is available. The Forest Service should take a whole watershed approach to aquatic restoration, meaning it considers a full suite of restorative activities, including upland management that may reduce evapotranspiration rates and favor stream base flows and groundwater recharge. Riparian restoration and management should be implemented in conjunction with adjacent upland management to ensure timely implementation.
2. PRESCRIBED FIRE
Like upland areas, riparian areas experienced historic fire, and in many cases are dependent on fire (particularly hardwoods and aspen). OFRC supports the reintroduction of fire into riparian areas, either by direct ignition or by allowing prescribed fire to back burn into riparian areas as one of many tools available to restore riparian areas. Where Rx fire units are located adjacent to streams, RHCAs should be included in prescribed burn unit planning and implementation. More specific recommendations on prescribed fire will be developed in future zones of agreement.
OFRC supports activities that promote full, and natural complement of hardwood restoration including aspen, cottonwood, willow, alder, water birch and a variety of shrub species native to the ONF. OFRC also supports enhancing diversity of understory species composition typical for drier habitats, such as snowberry, ocean spray, serviceberry, chokecherry, etc. We acknowledge that recovery of these species can be difficult, if not impossible, where ungulate browse is heavy, and therefore caging of planted and recovering hardwoods may be necessary. Where aspen restoration and recovery is prioritized, we recommend that the ONF follow the OFRC Aspen Zones of Agreement.
4. WET MEADOWS
OFRC supports meadow restoration/enhancement that cuts and removes conifers that have encroached into meadow habitats and planning that seeks to reintroduce prescribed fire into these systems. These treatments should be tied to the surrounding vegetation type by developing site specific prescriptions. Meadow boundaries should be determined through analyzing a mixture of site-specific products, including but not limited to LiDAR maps, soil mapping done through the Terrestrial Ecological Unit inventory, site visits, professional judgment and past aerial photographs.
5. LIVESTOCK AND WILD UNGULATES
Where riparian areas have degraded or impacted conditions from livestock (cattle, sheep, horses) and wild ungulates, the Forest Service should consider fencing or other strategies in their aquatic restoration treatments to reduce access to recovering and restored RHCAs. The OFRC acknowledges that fencing is not feasible or necessary along all RHCAs and therefore should be prioritized for RHCAs that are in the process of being restored and recovering. Wildlife friendly fencing that minimizes entanglement and targeted caging of hardwoods should also be employed. The OFRC understands that the Forest Service will work with permittees to facilitate livestock management along with recovery of aquatic/hydrological resources.
6. LARGE WOODY DEBRIS/COARSE WOODY DEBRIS (LWD/CWD)
Research has indicated that current management objectives from the INFISH standard for pieces of large wood per mile (e.g. >20 pieces per mile) may be too low and in managed watersheds the target should be set higher for the interim until wood loading can occur within the natural range of variability (Fox and Bolton 2007, Wohl et al. 2017a, Wohl et al. 2017b). Based on supporting literature (Montgomery et al. 1995, Beechie and Sibley 1997, Seixas et al. 2020), we support a minimum desired large wood frequency of 20 pieces per mile with an elevated target of 80 pieces per mile in degraded stream reaches proposed for restoration to enable reaching other INFISH RMOs such as pool frequency. Coarse wood harvested from RHCA’s should be used for in-stream/riparian habitat and where not available, coarse wood from adjacent uplands should be added to streams to meet coarse woody debris requirements.
7. BEAVERS AND BEAVER DAM ANALOGS
OFRC supports the use of in-stream “beaver dam analog structures” that promote floodplain connectivity, provide pooling habitat, and encourage riparian vegetation restoration in appropriate locations. Monitoring of the efficacy and longevity of these structures should occur. OFRC also supports beaver reintroduction but recognizes that many reaches are unlikely to support beaver populations or dam building activities due to their current degraded state. In conjunction with restoration activities, the OFRC encourages the USFS to explore beaver reintroduction where feasible.
As the population of Central Oregon grows and the ONF gains popularity among visitors, recreation demands will inevitably increase throughout the forest, likely impacting riparian areas. We recommend that planning and projects pertaining to trails, campgrounds, and dispersed camping seek to minimize and mitigate recreation impacts on RHCAs.
9. HISTORICAL/CULTURAL STRUCTURES
Existence of historical sites should not preclude potential actions for restoration and management activities in riparian areas. Components can be preserved, but not with detriment to activities and vice versa. The ONF should consult with the Confederated Tribes of Warm Springs Cultural Resources and Culture and Heritage Staff to address preservation of cultural sights and resources present within RHCA projects.
Road access to the Ochoco National Forest is important to many people for many reasons.
However, some roads are causing aquatic resource damage. The Forest Service should undertake an analysis at the project level to determine what roads are causing aquatic resource damage and propose road treatments (rerouting and alternative access) and stream realignment to address the adverse effects of those road segments. The NEPA analysis for road-related work should explain the tradeoffs associated with opening/maintaining roads vs. treatment.
OFRC supports culvert repair, replacement, and upgrades to improve fish passage and other aquatic processes.
12. STEWARDSHIP CONTRACTS
OFRC supports the use of Stewardship Contracts in project areas that include RHCA’s to fund RHCA restoration and management while utilizing contractors to complete restoration/management activities in conjunction with upland activities.
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Bjorn, T.C.; Reiser, D.W. (1991) Habitat requirements of salmonids in streams. W.R. Meehan (Ed.), Influences of forest and rangeland management on salmonid fishes and their habitats, Special Publication, vol. 19, American Fisheries Society.
Fox, M., Bolton, S. (2007). A Regional and geomorphic reference for quantities and volumes of wood in unmanaged forested basins of Washington State. North American Journal of Fisheries Management, 27:342-359.
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