Elaeagnus angustifolia: The Case For, The Case Against

Until this year, I had not noticed the honeysuckle-like fragrance of the Russian olive trees (Elaeagnus angustifolia). And, with their gray-green leaves, they provide a pleasing contrast to the darker leaves of the cottonwoods that also line the rivers. I have a friend who, not without reason, claims that they provide food for animals and fix nitrogen in the soil.

But, the smell of the flowers becomes cloying, the fruits are unpalatable to the human tongue (or at least they were to me when I tasted them), and, most importantly, in Colorado where I live, the tree is a non-native invasive species that rapidly crowds out native species. A report by Columbia University claims that in Colorado, Russian olive trees have replaced hundreds of thousands of acres of willow and cottonwood woodlands. The state categorizes the Russian olive as a noxious weed slated for eradication, containment, or suppression.

But, what about my friend’s claims? Although it’s true they provide food for birds, this is the case only for some species, and trees appear to reduce “avifaunal diversity.” Cavity-nesting birds and woodpeckers, for example, do not use the Russian olive tree, and so its spread destroys the richness or variety of birds present in a location.

What about its nitrogen-fixing abilities? According to various Web sites, this quality interferes with “nutrient cycling” by attracting other species that prefer high nitrogen soils and outcompete native species that survive on less fixed nitrogen.

Finally, Russian olive trees are almost impossible to control. They do not attract insects, grow from suckers (making pruning ineffective), and resist fire. They thrive on a variety of water, temperature, and soil conditions.

My friend’s knowledge is true as far as it goes, but taken within the context of the riparian areas of the western United States the case against the Russian olive tree is watertight.