Tamarisk, the scourge of the desert, creeps into Aspen area | AspenTimes.com

Tamarisk, the scourge of the desert, creeps into Aspen area

Visit a desert canyon that possesses even a hint of water and chances are good you will have a nasty encounter with tamarisk.

Desert rats know and loath the shrub or small tree. Hikers are forced to fight through long stretches of it in canyon bottoms. Regular visitors to Lake Powell have watched it create a nearly impenetrable barrier to parts of the shore over the last decade or so.

Water managers estimate the trees absorb 300 gallons of water per day, or between 2 million and 4.5 million acre-feet of water per year. That’s enough to irrigate 1 million acres of farmland for a year or supply 20 million people with domestic water.

Colorado Congressman Scott McInnis’ office calls tamarisk “the poster child” for non-native plants invading the river ecosystems.

There are numerous theories about how tamarisk got introduced to the West, according to Tim Carlson, executive director of the Tamarisk Coalition. The nonprofit organization is devoted to stopping the shrub from spreading further and eliminating it where it already has taken hold. It was possibly brought in from Eurasia during the Dust Bowl for wind breaks and for erosion control along riverbanks.

Without natural checks and balances, it has spread at will, Carlson said. Without aggressive treatment, he fears it will sweep through Colorado’s West Slope.

“Grand Junction looks now like Moab did 20 years ago,” he said.

There are definitive consequences. Tamarisk, also known as salt cedar, crowds out native trees like cottonwoods, which often give desert landscapes their distinctive feel. Creeks already slowed to a trickle in dry desert environments can be sucked dry by the thirsty plants with roots that burrow down 100 feet.

Tamarisk has already popped up in the Roaring Fork Valley drainage. About 30 seedlings “and one full-blown tree” were discovered beside the warm waters of the Penny Hot Springs, said Jim Lewis, Pitkin County vegetation manager.

His crews cut the tree and seedlings nearly to the ground then immediately smeared an herbicide onto the nubs and stump. The herbicide must be used or shoots will sprout from the stump and make the shrub even thicker than before, Lewis said.

Lewis said other seedlings have been found and destroyed in Little Elk Creek and along Highway 82 near the dump turnoff. He said seeds likely get spread when they stick to a raft or kayak in Utah and then get put into the water back here. In other cases, seeds stick to vehicles that were used for a recreational trip to the Utah desert.

McInnis introduced a bill in the U.S. House seeking to create a $100 million federal fund that could be used for pilot projects to eliminate tamarisk. McInnis’ plan was to supply money to try different treatments then use the results to craft an eradication plan.

The fund would be just the beginning of what’s needed. Numerous canyons are covered with acres of the shrub.

“It is going to be a daunting task but this is a way to kick start the program,” said Blair Jones, a spokesman for McInnis.

But the bill never made it to the floor for a vote before the House adjourned for the year last week.

Nevertheless, the fight continues on a number of fronts, said Carlson. The Nature Conservancy, one of the world’s most popular environmental groups, has embarked on a four-year effort to free the San Miguel River of tamarisk from Telluride to Uravan.

All told there are 12 tamarisk removal projects under way in western Colorado and five in the Moab area, said Carlson.

The financial cost of the greater effort is staggering. Carlson said chopping the tamarisk by hand costs $1,500 to $5,000 per acre, depending on the terrain. Mechanical cutting costs $200 to $400. Both methods require the herbicide to be applied by hand because it must only be painted on the stumps to prevent environmental degradation.

Nature might supply the best alternative. The U.S. Department of Agriculture experimented with a Chinese leaf beetle in Colorado. That beetle helps keep tamarisk from spreading too drastically in the Far East.

In Colorado, the beetles were allowed to munch away in 100 enclosed acres along the Arkansas River. Researchers wanted to make sure they wouldn’t create some unforeseen problem while ridding the West of tamarisk. So far, results appear promising, according to Carlson.

“These bugs just eat tamarisk ” nothing else,” he said.

Scott Condon’s e-mail address is scondon@aspentimes.com

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