Every year 350,000 acres of priority sagebrush areas are being encroached.
The sagebrush biome defines the American West. It’s where the deer and the antelope play, where modern-day cowboys and cowgirls work their herds, and where the sweet smell of sagebrush drifts across the windswept range. But this vast region — and the people and wildlife that depend on it — is in trouble.
According to the Sagebrush Conservation Design, America is losing 1.3 million acres per year of sagebrush grasslands. "Conifer encroachment" is a leading cause of sagebrush loss today, and it is caused by native trees, like junipers, pines, and Douglas fir, which are spreading into sagebrush.
Healthy woodlands and forests are very important for their inherent values to people and wildlife. However, conifer encroachment into adjacent sagebrush threatens the values of these ecosystems, including wildlife habitat, water availability, fire resilience, and forage productivity.
Be sure to check out the Reducing Woody Encroachment in Western Rangelands Technical and Pocket Guides for the latest, practical, science-backed solutions for addressing encroachment in sagebrush country.
Why Is Conifer Encroachment in Sagebrush a Problem?
Healthy sagebrush grasslands provide critical food for grazing livestock and wildlife. Conifer encroachment reduces the productivity of perennial grasses and eliminates shrubs essential to sustaining grazing animals like mule deer and pronghorn.
Sagebrush grasslands are like upside-down forests, storing most of their carbon and nutrients deep in the soil. Conifer encroachment alters carbon and nutrient cycling, shifting resources above ground where they are more susceptible to loss by fire.
Many unique animal species, like the sage grouse, are found nowhere else in the world but in sagebrush grasslands. When trees move in, sagebrush-obligate wildlife disappear.
When conifer encroachment crowds out native bunchgrasses, it reduces resistance to invasive annual grasses. Maintaining the deep-rooted plants of sagebrush grasslands is key to keeping weeds like cheatgrass at bay.
Conifer encroachment greatly increases woody fuels in sagebrush grasslands, making wildfires harder to fight and impacts more severe.
By impacting native grasses and forbs, conifer encroachment reduces the ability for rain and snowmelt to infiltrate soils. This lowers moisture availability and increases erosion.
As a general rule, humans love trees. It’s not surprising — there’s a lot about trees to like! However, across the globe, vast swaths of the landscape are naturally treeless. In fact, they make up 40% of all terrestrial ecosystems. These meadows, grasslands, and shrublands are some of our most productive and important ecosystems, and they provide society with fertile grazing lands, open space and world-class recreation, and a remarkable diversity of unique wildlife.
Unfortunately, these grassy biomes are among the most imperiled globally, threatened by many factors including tree expansion. In the American West, conifer encroachment in core sagebrush areas results in altered fire regimes, reduced forage productivity, depleted water resources, habitat loss for sagebrush-dependent wildlife, and more.
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What Can We Do About Conifer Encroachment?
Science shows removing trees early in the encroachment process is one of the few actions proven to be effective at protecting and improving sagebrush ecosystems.
The best way to conserve sagebrush is to "defend the core" by working together to prevent the spread of trees in and around core sagebrush areas. Core sagebrush areas represent the best of the best, our last remaining intact sagebrush landscapes. Since much of sagebrush country is a mix of public and private land, it’s important to work across ownership boundaries.
Thousands of ranchers, rangeland practitioners, and land managers are coming together throughout the sagebrush sea, working across boundaries to remove encroaching conifers. These efforts are restoring millions of acres of sagebrush rangeland, improving productivity and wildlife habitat. Photos: Connor White.
How Can We Balance Sagebrush and Woodlands?
Careful planning is needed to ensure conifer removal is done in a holistic manner that considers a broader suite of other ecological and societal values. Targeted conifer removal and healthy woodlands are not incompatible resource management goals but can, and should, be intentionally balanced across the landscape.
While solutions to the conifer encroachment problem in core sagebrush areas are relatively simple and effective, achieving lasting results at large scales that considers a range of social and ecological values requires coalitions of motivated land management agencies, community partners, and landowners working together across boundaries.
