Last updated: June 10, 2016
NPS photo by Lori Makarick
- GETTING READY FOR 2016:
A Call to Action
- Action Item:
- Scaling Up
- Year Accomplished:
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.