Shrubs Of The Great Basin: A Natural History

Tamarisk

Tamarisk Tamarix spp. The Tamarisks are all ofgraceful and distinctive appearance, with light and feathery foliage and large, loose panicles of pinkish flowers. . . . As they are inhabitants of warmer arid regions, they are well adapted for countries of similar climatic conditions. They are also excellent for seaside planting. They grow well in saline and alkaline soil and thrive in the very spray of the salt water. -Liberty Hyde Bailey, CYCLOPEDIA OF AMERICAN HORTICULTURE THE GENUS Tamarix occurs naturally from western Europe and the Medi, terranean to North Africa, northeastern China, India, and Japan. The number of species is variously estimated to be between fifty and ninety. Ber, nard R. Baum of the Plant Research Institute in Ottawa, Canada, wrote a monograph on the group a few years ago that recognized fifty,four species. Of these, eight have become naturalized in North America, primarily in the Southwest, though one species is grown as far north as southern Canada. The colonization of the Great Basin by tamarisk is dramatically portrayed in a research paper by Earl Christensen entitled "The Rate ofNaturalization of Tamarix in Utah." Christensen looked at the historical records for Utah Lake, the Great Salt Lake, the Colorado River, and the Green River. He could find no evidence that tamarisks were present at any of these locales prior to 1925. As late as 1934, Seville Flowers, in his publication on the vegetation of the Great Salt Lake region, makes no mention of its occur, renee there. But twenty years later it was common. Similarly, tamarisks were recorded at Utah Lake in 1926 and became common in the period from 1930 to 1942. Now, throughout the Great Basin, they are abundant in wet 106 Tamarisk J08 TAMARICACEAE areas, whether saline or not. Outside of the Basin, Ivar Tidestrom recorded tamarisk along the Virgin River near Saint Thomas, Nevada, in 1919. Tamarisks are easily recognized by their small, scalelike leaves, very much like those of juniper, though smaller, and their slender, supple branches. They are, in fact, known as salt cedars by many. Linnaeus, the father of the so-called binomial system of naming plants, mistakenly described one tamarisk as a species of arborvitae. Several species are so well preadapted to Great Basin saline and alkaline soils that to the uninitiated they might well appear to be native shrubs. A traveler along the western shore of Walker Lake will see concentric rows of virtually pure stands of tamarisk, each row marking a former shoreline of this rapidly disappearing lake. The species along Walker Lake is known as T. parviflora. This is the easiest species to recognize when in bloom, since its tiny, pink flowers have only four petals. All other introduced tamarisks in the Basin have five petals. In the same general area can be found a species known as T. chinensis. Another species, T. ramosissima, appears to be a little less common. It can be found in the Fernley Wildlife Management Area and around the Soda Lakes in Churchill County. These last two species are rather difficult for the novice to separate. T. parviflora is found in southern Europe and Asia Minor from Yugoslavia to Turkey. T. chinensis, as might be guessed, occurs from Mongolia and China to Japan. T. ramosissima is found from the Ukraine and Iraq east through China and Tibet to Korea. Tamarisks were originally planted as ornamentals and as windbreaks, but their profligate nature soon demonstrated that all such introductions should be carefully monitored if major ecological catastrophes are to be avoidedwitness the Australian gum trees and Scotch broom in California or halogeton and Russian thistle in the Great Basin. Some introductions, of course, are accidental, as was the case with Russian thistle, and probably such errors are inevitable given the nature of modern commerce. However, some problems that have resulted from deliberately introduced forms might have been avoided if sufficient research had been done beforehand. In many instances, introduced species have grown out of bounds because the natural enemies which kept them in some sort of balance in their homelands are missing. The result is that many native species have been crowded out of some areas. Angus Woodbury, Stephen Durrant, and Seville Flowers found that, in 1958, tamarisks made up 19 percent of the total vegetation cover along the TAMARISK 109 streamside ofGlen Canyon. They found that tamarisks usually occupied the sandier areas and willows occupied the muddier sites. They concluded that competition between...