Exotic Tamarisk Management

Tamarisk along the Colorado River

Tamarisk, (Tamarix spp.) commonly known as salt cedar, is an exotic (non-native) shrub or tree that grows in dense stands along rivers and streams in the west. Tamarisk, introduced to the U.S. in the 19th century as an erosion control agent, spread through the west and caused major changes to natural environments. Tamarisk reached the Grand Canyon area during the late 1920s and early 1930s, becoming a dominant riparian zone species along the Colorado River in 1963 (following completion of Glen Canyon Dam).

 

The impacts caused by tamarisk in the southwest are well documented. These prolific non-native shrubs displace native vegetation and animals, alter soil salinity, and increase fire frequency. Salt cedar is an aggressive competitor, often developing monoculture stands and lowering water tables, which can negatively affect wildlife and native vegetative communities. In many areas, it occupies previously open spaces and is adapted to a wide range of environmental conditions. Once established in an area, it typically spreads and persists.

Through a public review process, called an Environmental Assessment / Assessment of Effect, park management evaluated the impacts to natural, cultural and wilderness resources, and solicited public comments. Through this process the environmentally preferred alternative was selected, and includes the control of tamarisk in side canyons, tributaries, developed areas, and springs above the pre-dam water level of the Colorado River within Grand Canyon National Park.

Crews remove tamarisk through a combination of mechanical and chemical controls, allowing for native vegetation to recover. The size of the plant usually dictates how it is removed. Methods include pulling, cutting to stump level, or girdling it to leave the dead tree standing for wildlife habitat. The combination of hand tools and herbicide ensures maximum effectiveness with minimum impact to visitors and the environment. The particular method used is specific to each site and determined by the restoration biologist or on-site project leader.

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Reports and Documents

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Download the Tamarisk Site Bulletin
Tamarisk Management and Tributary Restoration March 2011 (240 kb PDF File)

Download the Tamarisk Program Overview Poster
Tamarisk Management in Grand Canyon:
Past Challenges, Current Efforts and Future Direction February 2009 (213 kb PDF File)

Download Grand Canyon Exotic Plant Species
Vegetation Management Bulletin (117 kb PDF File)

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Download the Tamarisk Eradication and Tributary Restoration Project Reports

Phase I Final Report 2005 (3.12 MB PDF File)Tamarisk Eradication and Restoration of 63 Tributaries

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Phase II-A Final Report 2007 (1.50 MB PDF File) Management & Control of Tamarisk and Other Invasive Vegetation at Backcountry Seeps, Springs and Tributaries in Grand Canyon National Park

Phase II-A Final Report 2007 Appendices Only(45 MB PDF File)

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Phase II-B Final Report 2008 (2.5 MB PDF File) Management & Control of Tamarisk and Other Invasive Vegetation at Backcountry Seeps, Springs and Tributaries in Grand Canyon National Park

Phase II-B Final Report 2008 Appendices Only (50 MB PDF File)

Final Map (4.05 MB) from Phase II-B Final Report

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Download the Finding of No Significant Impact - July 2002

FONSI Tamarisk Management and Tributary Restoration (212 kb PDF File)

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Download the Environmental Assessment - February 2002

EA Tamarisk Management and Tributary Restoration (1.6 MB PDF File)