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Yurok Tribe Leads Massive Revegetation Project

Tribe, Partners Restore Klamath River’s Reservoir Reach As Dams are Removed


Under contract with Resource Environmental Solutions (RES), the Yurok Fisheries Department is leading a monumental project to restore the diverse, native flora that once flourished within the Klamath River’s 38-mile-long reservoir reach.

During the last six weeks, the Yurok Revegetation crew collaborated with smaller teams from Siskiyou Biosurvey and Native Ecosystems Inc. to hand sow billions of native plant seeds and over 28,000 acorns in briefly bare earth behind the bygone Iron Gate, Copco and J.C Boyle reservoirs. In the 2,000-acre project area, the tribal crew and corporations also manually planted approximately 76,000 trees and shrubs representing nearly 100 native plant species. Currently, countless small seedlings have begun to cast a sea of green across the empty reservoirs.

The Yurok Fisheries Department’s Senior Riparian Ecologist, Joshua Chenoweth, designed the revegetation plan to mimic, as much as possible, the interconnected plant communities that existed in the Upper Klamath River for millennia.

The massive revegetation project is part of a multifaceted, tribe-initiated effort to remove four dams and restore the ecological void left in their wake. The years-long revegetation component seeks to strengthen habitat to support struggling native fish stocks, such as fall Chinook salmon, ESA-listed spring Chinook and coho salmon, steelhead trout and Pacific lamprey. The rewilding of this ecologically distinct stretch of the Klamath will also benefit 240 vertebrate species, ranging from river otters to ring-tailed cats.

The holistic revegetation project’s primary objectives include:

  • Establish interconnected, biologically diverse and resilient ecosystems that support robust salmon runs before the dams.

  • Create year-round habitat for native fish, mammals, birds, amphibians, reptiles and insects.

  • Encourage environmental complexity to enhance culturally invaluable salmon, steelhead and Pacific lamprey stocks.

  • Stabilize several feet of fine silt trapped behind the dams for the last 57 to 106 years.

Concurrent to the revegetation project, Klamath River Renewal Corporation construction crews are working hard to dismantle the remaining three of four dams by October. The Fisheries Department, Yurok Tribe Construction Corporation and RES are evacuating sediment from the reservoirs in preparation to rebuild 38 miles of salmon habitat in the main-stem Klamath.

The dam removals, habitat work and revegetation effort are primary parts of the most ambitious salmon restoration project in history. The project will reopen 400 miles of historic salmon spawning habitat, improve water quality within 190 miles of the Klamath and reduce fish disease infection rates.

The Upper Klamath is located at the intersection of the Klamath, Siskiyou and Cascade Mountain ranges. Its topography, climate and geology vary greatly from the steep volcanic canyons above Copco Dam to the relatively flat pine forests around JC Boyle reservoir. This complex landscape supports a wide variety of ecosystems, including: floodplains, wetlands, oak woodlands, mixed conifer forests, pine woodlands, wet and dry meadows, grassland-chaparral and rocky escarpments.

Starting in 2019, the Yurok Revegetation crew sustainably harvested millions of seeds from native plants within these ecosystems. From the original stock, regional nurseries amassed approximately 17 billion seeds for the restoration project.

During this phase, Chenoweth drafted the blueprint to bring the reservoir reach back to life. He mapped the reservoir reach and developed detailed contingencies for multiple water year types. The riparian ecologist and the Yurok GIT Department plotted the reservoir reach into 42 planting zones, including high priority and control areas. Each zone was refined into smaller sections. The Yurok GIT Department imported a mobile map package with the planting zones and sections onto geo-enabled digital devices to guide revegetation crew members.

Chenoweth also curated seven native seed mixes, consisting of up to 20 integrated plant species, for specific environmental conditions within each section. The seed aggregates perform distinct functions. One mix, comprised of fast-growing grasses and flowering plants, halts erosion.

In the months prior to project implementation, the Yurok Revegetation crew assembled the seed blends, plugs, container and bare-root stock into groups of symbiotic plant communities reflecting the natural composition of flora in the Upper Klamath. The crew stored plant material in climate-controlled shipping containers throughout the reservoir reach for quick deployment.

In late January, as the water receded from Iron Gate Reservoir, the revegetation team rapidly planted 30,000 pounds of grass, herb and forb seed mixes throughout the reservoir reach, while the silt was still wet to get a head start on noxious weeds.

During the laborious seeding effort, the crew simultaneously planted acorns, milkweed rhizomes, trees, shrubs and bunch grasses. To give the plants the best shot at surviving the hot and dry summer ahead, the crew put a tremendous amount of care into planting every seed, sapling and grass cluster. For members of the crew, the restoration of the Klamath River’s reservoir reach is an expression of a timeless, reciprocal relationship between native people and the natural world.

When they reach a certain age, each botanical species contributes to the plant community and ecosystem. These symbiotic relationships improve the viability of individual plants and the plant community.

Here are a few examples of the plant species incorporated into the revegetation project and brief descriptions of the innumerable roles they occupy in the environment. Silverbush lupine (Lupinus albifrons) deposits nitrogen in the soil, while its showy purple flowers supply bees and butterflies with pollen and nectar. Common yarrow’s (Achillea millifolium) long tap root transports essential calcium and potassium from deep underground to the soil surface and its palm-sized inflorescence entices dozens of pollinators, including hummingbirds. Grasses such as June grass (Koeleria macrantha), squirreltail (Elymus elymoides) and blue wildrye (Elymus glaucus) stabilize soil and serve as a cool season food source for native creatures, such as moth larvae and mule deer. Turkey Mullien (Croton setiger), a squat broad-leaf plant, harbors pest predators and produces forage for doves, quail and turkeys.

Plants, like Garry and black oaks (Quecurs garryana and Q. kellogii), provide more than the rest. In the spring and summer, the trees’ dense canopy is a haven for resident and migratory songbirds. In the fall, numerous animals feast on the nutritionally dense nuts that drop from oak branches. A myriad of beneficial fungi resides in the layer of leaves at the base of the hardwood and several inches into the soil. Many of these fungi nourish native wildlife, convert organic material into natural fertilizer and much more.

Near the reservoirs’ former waterline, the Yurok Revegetation crew planted acorns next to existing oak stands to foster a connection between mycorrhizal fungi and the seedlings. These fungi furnish water and nutrients to oak trees in exchange for carbohydrates. Mycorrhizal fungi also suppress plant pathogens and increase quantities of good soil bacteria. Mycorrhizas play a critical part in the success of almost all plant species. The native grasses and forbs planted around the oaks will connect to the fungal grid too.

At strategic locations in all three reservoirs, the revegetation crew established facilitation patches or dense plantings of habitat-specific plants. Ranging in size from .22 acres to larger than 2 acres, facilitation patches accelerate positive plant interactions, which in turn expedites plant growth and improves survival.

Maturing faster, trees in facilitation patches reach seed-bearing age earlier than those sown in a standard planting configuration. These concentrated plantings will become natural seed banks for the remainder of the restoration area. Drawn in by the abundance of seeds, birds and mammals will spread the reproductive material to new locations. Furthermore, tree canopies within facilitation patches close faster and discourage noxious weed encroachment. The revegetation crew installed facilitation patches in every ecosystem within the reservoir reach, including the riparian zone.

In the riparian environment, the revegetation crew planted Fremont cottonwood (Populus fremontii), oaks and Ponderosa pine (Pinus ponderosa) trees. The trees and tall shrubs will one day shade the river for salmon and the sedge will attract the insects that sustain baby fish. More robust and diverse riparian plantings will be installed in the next two years as the river and its tributaries develop and settle into natural pathways. Species to be planted include, big-leaf maple (Acer macrophyllum), white alder (Alnus rhombilfoia) and red-osier dogwood (Cornus sericea). Riparian plantings will create sprawling root networks that will capture and store fluvial sediment and excess nutrients.

Depending on the plant, it will take varying amounts of time for the 100 species to reach maturity. Many of the herbaceous plants will start producing flowers and seeds this year or next. The trees require a bit more time. In a decade or less, dark green foliage will follow the contour of a clear Klamath River through the reservoir reach. As more years pass, it will appear as if the dams were never there at all.


The Klamath River is the third largest salmon river in the lower 48 states. Currently, the Klamath’s salmon stocks are less than five percent of historic numbers in large part because of the dams. Two decades ago, the Yurok Tribe identified the decommissioning project as the single most effective action to restore struggling fish runs.

The removal of the dams will facilitate several short- and long-term improvements to the river’s ecology. Later this year, salmon are expected to spawn above the dams for the first time since 1918. Their progeny will not have to contend with extreme levels of Ceratonova shasta disease. In recent years, fisheries biologists observed fatal C. Shasta infections in nearly 100 percent of sampled juvenile salmon.

The river will be cooler when adult spring and fall Chinook salmon are running in the late summer and early fall because water will flow freely instead of stagnating behind the dams. With dams in, the lower Klamath typically reached 80 degrees, well above the lethal temperature for salmon.

Additionally, it will be safe to swim in the river during the warm months because the reservoirs will no longer emit elevated concentrations of toxic blue-green algae.

Within the next three to four years, the remaining sediment impounded behind the dams will wash out to sea or come to rest on the riverbank, where riparian plants will quickly colonize the fluvial substrate. The river’s health will improve every year.

In the long-term, fisheries biologist expect salmon to reproduce in the cold creeks that flow into Upper Klamath Lake, where there is an abundance of great habitat for baby fish. The restoration work that the Tribe and its partners plan to implement in the Klamath largest tributaries, including the Trinity, Scott and Shasta Rivers, over next five years will further enhance fish stocks.

The Klamath’s tributaries are where most salmon spawn and die. As the number of spawning fish increases, native birds and mammals will consume their carcasses, facilitating the spread of marine-marine derived nutrients across the landscape.

The post-dam removal prediction of what the Klamath will look like in a decade is largely based on the cascade of positive outcomes that occurred after the removal of the Elwha River dams, now the second biggest project of its kind in US history. Chenoweth led the restoration of the Elwha after the Elwha and Glines Canyon Dams were dismantled in 2012 and 2014. Today, in the footprints of the two reservoirs, Washington’s Elwha braids and bends through a vast floodplain flanked by 30-foot-tall trees, broadleaf shrubs, flowering herbs and grasses. Evidence of the erstwhile dams is barely discernible. Salmon and especially steelhead populations are increasing every year.

Situated on the Olympic Peninsula, the Elwha River drainage is cooler and wetter than the Upper Klamath River. The recovery of the Upper Klamath may take longer due to the hotter and drier summers and colder winters. Chenoweth and other world-leading restoration experts think it will take decades for the recently planted trees to assume the form of a functional forest with multiple canopy layers in the riparian zone. At which time, the uplands will become a mosaic of mixed conifer and hardwood forests, chapparal, oak woodlands and meadows.

At this stage, the reciprocity between plants will extend back to humans in the form of a productive river, cultural preservation, food sovereignty, carbon storage, economic stability, outdoor recreation opportunities and clean air.


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