Organizations Tackle Invasive Tree Species in Animas Basin near Durango

Apr 11, 2018

The invasive Russian olive tree can cause havoc in river ecosystems around the West. But a group of organizations outside of Durango has found a way to remove not only to remove the trees, but also to help the surrounding community in other ways.


Despite their name, Russian olive trees have little to do with real olives. You can’t make oil out of their fruits, and they are only very distantly related to true olive trees. They’re only called “olive” trees because of their medium size, their silvery green color and their small dry fruits.

If you travel in the West, you will likely see lots of these trees along rivers and in riparian areas. But they haven’t always been here. They were introduced to the United States as an ornamental plant sometime around the turn of the 20th century.

When Russian olive trees enter an ecosystem, they often take over. They grow faster than other native plants and out-compete them for water and nutrients. Their dying leaves upset the balance of nitrogen in the ecosystem. Native birds and wildlife don’t nest in them, so the trees knocks their populations out of balance as well.  

“One way to think of invasive plants is sort of like biological pollution,” said Amanda Kuenzi, Community Science Director at Mountain Studies Institute in Durango. She gave an example of the difference between biological pollution and chemical pollution.

“If we had an oil spill, it’s terrible, and it’s really bad, but we can clean that oil up,” she said. “It’s out of the river.”

But invasive species are different, she explained.

“They reseed. Every year that they’re putting out seeds, [they’re] just exponentially reproducing,” she said.

“Each one of those seeds becomes a new tree that can reproduce, so the problem just grows, and grows, and grows.”

She explained that Russian olive stands in deserts and warmer, low elevations are too thick to remove all at once.  But along the Animas River above Durango, temperatures are a little too cold for the trees to really take hold.

However, it may not always be like that. Warming average temperatures may make it easier for the trees to grow at those higher elevations in the future.

Most public lands agencies have programs to get rid of Russian olive trees. But Kuenzi explained land ownership boundaries between public and private lands are “like a checkerboard.”

Since public lands agencies don’t work on private lands, Mountain Studies institute teamed up with land conservancy organizations to reach out to private landowners and help them clear the trees from their properties. The landowners share costs and workloads of the species removal with the organizations.

“As those people were willing to eradicate Russian olives on their parcels, they could talk to their neighbors,” Kuenzi said. “I found that neighbors talking to neighbors was the most powerful tool.”

However, Russian olive trees can’t simply be cut down. The plants quickly begin to re-grow after they are cut. Kuenzi said she has seen hundreds of re-sprouts come from one cut stump.

So Mountain Studies Institute hopes to eradicate the trees by cutting them down and also applying herbicides. But with herbicides, Kuenzi says they’re being careful.

“We definitely don’t want to see tons of chemicals going into our waterways--that’s not the way herbicide should be used,” she said. “The way we’re using herbicide in this case is extremely localized, just very carefully applying it stump by stump.”

Some of the smallest trees can be sprayed at the base to kill them completely, she explained. The larger ones can be sliced at the trunk and injected with a small amount of chemical to create standing dead trees for wildlife habitat. And the trees can also be cut down completely and sprayed at the stump so they won’t grow back. Young people from the Southwest Conservation Corps do most of the labor.

“The landowners that I’ve worked with are so impressed that the kids are in there day in and day out with chainsaws,” Kuenzi said. “It’s hot sometimes, and they’ve got chaps, and hard hats, and all the safety equipment…”

The goal is to return the habitat back to how it was before the Russian olives were introduced. Kuenzi said it used to be dominated by native cottonwoods, river birch, and willows.

Mountain Studies Institute says it has cleared almost 300 acres of Russian olive trees so far. They have used the same tactics for the similarly-invasive tamarisk trees. Plus, Kuenzi’s team has found a way for their project to have even more impact in the community.

“One of the problems we ran into was what to do with all the waste materials after we cut down the Russian olives,” she said.  

But the answers sometimes present themselves. One of the Rotary clubs in town distributes firewood to low-income seniors and families in the area to help them heat their homes. Travis Ward, a member of Durango Daybreak Rotary, said the project has worked well so far.

“Amanda would call, and say ‘we’ve got a pile out by Animas School,’” Ward said. “We’d go out there and load it up, and take it out to our wood site. Hopefully it’ll be aged enough to use next winter.”

Kuenzi said there is a lot of community support for the program, and she hopes it can continue. She is working with local organizations and state agencies to secure funding for the upcoming summer.

This story is part of Western Slope Resources Reporting, a collaboration between community radio stations KSJD, KBUT, KVNF, KDNK, and KOTO. It provides in-depth coverage of how people and organizations are finding creative and positive ways to overcome natural resource-related challenges.