Holding the Line

Frequent, low-intensity fires were once common on high-elevation sagebrush lands. These fast-moving fires killed young trees while revitalizing sagebrush, native grasses and wildflowers. Yet more than a century ago, Western settlers began suppressing most fires. That gave Douglas fir and juniper forests an opening to extend their reach into the Sagebrush Sea, where they shade out sun-loving sage. “As those trees outcompete the native shrubs and grasses, we lose forage for wildlife and for livestock,” explains Sean Claffey, Southwest Montana Sagebrush Conservation Coordinator with The Nature Conservancy. “We also lose suitable habitat for species like greater sage-grouse." 

The trees are just one invader in a larger siege on the Sagebrush Sea, which is being lost at an astonishing rate of 1.3 million acres each year. Invasive grasses, such as cheatgrass, are also elbowing out native plants. And as more people move to the region, developers bulldoze sagebrush for subdivisions and roads. These combined pressures have made the Sagebrush Sea among the most vulnerable ecosystems on Earth.

The threat is so severe that no one entity can take it on alone. So TNC has joined forces with local landowners, federal and state agencies and other conservation organizations to forge the Southwest Montana Sagebrush Partnership. Tackling conifer expansion is one of its many approaches to conserving our rangelands. 

Chainsaw crews first cut down young trees outside the forest edges. Next, prescribed fire specialists conduct controlled burns that mimic the low-intensity wildfires once common on the land. “When we use prescribed fire in sagebrush, we leave little island pockets of sagebrush that reseed that site,” Claffey notes. “And we see at some sites in southwest Montana that sagebrush return in as little as five years. What you don't see is the conifer seedlings coming back up through the sagebrush.”

TNC and our partners work with landowners to share best practices for controlling conifers. Says Claffey, “When we start realizing how much common ground we have, that's where we start having successes on the ground.”