Saltcedar Control Program

The Owens Valley Monitor 1999-2000

Saltcedar Control Program
Brian Cashore,
Saltcedar Control Project Coordinator

The effects of agriculture, dam construction, groundwater pumping, livestock grazing, urbanization, and other human activities have led to the decline of many southwestern riparian vegetation communities. Invasive weed establishment is often a by-product of such disturbance. The dry Lower Owens River channel exemplifies some of these processes in action.

If you had visited this stretch of the river between October 1999 and March 2000 you would have seen the Inyo County Saltcedar Control Program crew clearing the channel of a virtual monoculture of approximately thirty-year-old saltcedar, or tamarisk, trees. The saltcedar control work was focused in this area this year to prepare the channel for the impending water releases to the river channel as part of the Lower Owens River Project. Though we exceeded our goals for the season, there is still much work yet to be done. We have witnessed firsthand that a century of human disturbance to a riparian ecosystem cannot be reversed within a few seasons.

1999 saltcedar control crew: from left to right, Brian Cashore, Jerry Zatorski, Bill Howe, Chuck Spresser, Rick Puskar, Nathan Reade, and Jason Denio. Lori Gillem, also a crew member is not in the photo. (Click on image to enlarge).

This year's work was accomplished with our largest crew yet, including Jason Denio, Lori Gillem, Bill Howe, Rick Puskar, Nathan Reade, Chuck Spresser, Jerry Zatorski, and myself. We alternated jobs throughout the day between cutting with chainsaws and brushcutters, spraying cut stumps, and "swamping," or clearing limbs and logs. Each day found us either working our way south along the banks of the dry Lower Owens River channel or cutting for days at a time on the adjacent flood plain benches, where dense thickets of thirty-year-old trees grew. These populations were established when runoff water released to the river during wet years deposited saltcedar seeds at the high-water points. It was always satisfying to look north and see the channel cleared of saltcedar, with an occasional willow tree, now free from competition, ready to re-colonize. The view to the south required philosophical thinking or a great sense of humor.

While the crew cleared an impressive 9 river miles of tamarisk this season the old-fashioned way, we sometimes wondered about our own competition. The newest tool in controlling saltcedar in the Owens Valley may be aliens. Legal ones from China. Diorhabda elongata is a tamarisk leaf-eating beetle that has been tested in quarantine in the U.S. for over ten years. The Saltcedar Control Program and LADWP are participating in a small-scale test of the effectiveness of these aliens in the valley. The study is being conducted by scientists from the U.S. Department of Agriculture. Eli Asarian, an ICWD college intern last summer, was invaluable in his assistance with this project as well as with other saltcedar work.

As new arrivals, the beetles seemed a little disoriented at first, but they eventually began feeding and reproducing on the contained test plants. The insects are extremely species-specific and have not demonstrated the ability to feed on any plant family other than that of the tamarisks. If successful, these beetles could eradicate up to 80% of the local saltcedar plants without herbicides, chainsaws, or harm to the native vegetation. If the USDA and the California Department of Food and Agriculture ultimately approve the use in California of biological control agents, such as the Chinese beetle, the Saltcedar Control Program will consider their use in the Owens Valley. This decision would be subject to a public environmental review process.

A landscape, such as the Owens Valley floor, that has experienced multiple disturbances over many years will reflect those changes in a variety of ways. The saltcedar in the valley and along the river is one such reflection. To restore a portion of the Owens Valley environment to a former or more natural state will require a tremendous amount of energy and expense. The Inyo County Saltcedar Control Program is attempting to reverse processes that began long ago, while getting the "biggest bang for the buck" out of available funding. Right now, that means cutting the plants down and treating the stumps. Biocontrol and other new techniques may offer promise, and we will always be open to options.

Someone looking ahead at the work yet to be done may question whether it is all worth it. What is the value of a monoculture of saltcedar versus a native riparian system? The answer involves taking responsibility for past disturbances and then deciding whether we should attempt to repair them or accept these altered lands as they are.

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