Russian Olive Tree (Elaeagnus angustifolia) categorized as an invasive species.
According to Columbia University:
“The Russian olive, with its tendency to spread quickly, is a menace to riparian woodlands, threatening strong, native species like cottonwood and willow trees. They are responsible for out competing a lot of native vegetation, interfering with natural plant succession and nutrient cycling and choking irrigation canals and marshlands in the western United States. This displacement of native plant species and critical wildlife habitats has undoubtedly affected native birds and other species. The heavy, dense shade of the Russian olive is also responsible for blocking out sunlight needed for other trees and plants in fields, open woodlands and forest edges. Overall, areas dominated by the Russian olive do not represent a high concentration of wildlife.
Control Level Diagnosis: The Russian olive has been categorized as a noxious weed in New Mexico and Utah, and as an invasive weed by California, Nebraska, Wisconsin and Wyoming state authorities. There is a serious concern that should the Russian olive continue to establish itself, it will become the dominant woody plant along Colorado’s rivers, where it is already taking over hundreds of thousands of acres of cottonwood and willow woodlands. Some cities are already taking steps to remove the Russian olive.”