April 21, 2007

You May Call It ‘Tamarack,’ but It’s Not

By Chris Woodka, The Pueblo Chieftain, Colo.

Apr. 21--Tamarack trees are not native to the Arkansas Valley and few, if any, grow here.

Tamarisks, or salt cedars, are a growing threat to water supplies, channel capacity and plant diversity in the Arkansas Valley.

Confusion persists, as in a recent "Tell It To The Chieftain" submission, about the two species.

Arkansas Valley natives have for generations called salt cedars "tamarack," adding to the confusion.

The tamarack tree, a type of conifer related to pine trees, is native to North America -- just not Southern Colorado. The tree's range includes the upper Midwest, Northeast, Canada and Alaska, according to the Natural Resource Conservation Service Web site.

Of the 11 species of tamarix, also called tamarisk, at least three are found in Colorado, according to NRCS data. None are native, but were introduced to the United States as ornamental plants. They are not conifers, but flowering trees.

The prolific salt cedars are the most widespread species in Colorado and they aggressively choke out all other forms of vegetation.

Introduced to the United States from central Asia in the mid-1800s as an ornamental plant, salt cedars spread rapidly along waterways. They draw salts from the soil and concentrate it in the areas around the plants, reducing the habitat for other species of plants and animals.

Salt cedars are resistant to fire and drought. When water is available, a mature tree can use 200 gallons per day and produce 2.5 million seeds. It will reproduce more quickly than other species.

Unlike native cottonwoods, which also use large quantities of water, salt cedars spread to drier, upland areas, tapping into potential sources of water.

The Tamarisk Coalition estimates removing salt cedars in the Arkansas Valley, the most heavily infested part of the state, could recover nearly 60,000 acre-feet annually, even after native vegetation is re-established.

No one is certain about who would benefit from recovering the water, however.

The topic came up at the Arkansas River Basin Forum in Rocky Ford during a discussion of the Arkansas River Compact last week.

State engineers Hal Simpson of Colorado and David Pope of Kansas could not immediately answer which state would benefit, and were hard-pressed to even begin to quantify the gains from tamarisk removal.

"There are some benefits, but they may not be as great because of the replacement by natives like cottonwoods," Simpson said. "The net benefit might be as high as 1 acre-foot per acre in some places, but it's expensive."

"It's expensive, but we've got to stay with it," Pope said. "I don't think we'll ever be able to completely eradicate it."

Others at the forum said tamarisk control is needed, even if it doesn't result in direct benefits of consumable water in the river. The flood control capacities of the Arkansas River in Las Animas and Fountain Creek in Pueblo have been reduced by thick tamarisk stands.

"I'm not totally convinced you'll be able to realize the savings in water," said Jim Broderick, executive director of the Southeastern Colorado Water Conservancy District. "But it has become a health and safety issue."

The Southeastern District is taking the lead in a tamarisk control program through a mapping project and strategic plan that would involve counties and state agencies. The district will later apply for federal funds to attempt to control tamarisk throughout the basin before the problem becomes worse.

The fear is tamarisk will fill in areas of light concentration, possibly doubling the amount of water they use in the Arkansas River basin. Reduced water availability could have negative consequences for all water users in the basin, especially junior water rights holders.


Copyright (c) 2007, The Pueblo Chieftain, Colo.

Distributed by McClatchy-Tribune Business News.

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