At the Flatiron Rock Trailhead in central Oregon’s Badlands Wilderness, a gnarled stump reaches out of a crack in the rocks. A centuries-old juniper tree stood here until last December, when vandals illegally cut it down and hauled it away.

“That tree is probably a lamp somewhere now,” says Gena Goodman-Campbell, wilderness coordinator for the Oregon Natural Desert Association, as she looks at what’s left. A $1000 reward offered by ONDA and other local environmental groups has failed to turn up any leads.

Old-growth western junipers (Juniperus occidentalis) are stooped and twisted, their furrowed red bark typically blanketed in lichen. No two are alike, and Goodman-Campbell points out one favorite after another as she works her way up the trail. This one’s roots have split a massive boulder; that one’s limbs are so bent they rest on the ground. Although junipers typically grow no taller than thirty feet, an individual might live for more than a thousand years—a tree a few miles south of here was dated at 1,600 years, and there are likely others even more ancient. These trees are irreplaceable, and cutting one down on public land is punishable by a fine of $100,000 and up to a year behind bars.

Strange, then, that while the Bureau of Land Management (BLM) is hunting for the Badlands timber poacher, it’s also ramping up efforts to remove western juniper from large swaths of eastern and central Oregon—in an attempt to restore the region’s sagebrush steppe ecosystem. Over the past 130 years, changes in land use and management practices have allowed juniper woodlands to expand their geographic range tenfold, profoundly altering the ecosystems they infiltrate. Today, land managers in Oregon and several other western states are struggling to regain some control over invading junipers even as they strive to protect the remaining old-growth stands not far away. Both native and invasive, the western juniper is a living contradiction. And like many stories of transformation in the American West, this one starts with the arrival of white settlers and their cattle.

Conifers tend to be sensitive to fire, and historically, junipers survived the fires that regularly swept across the arid inland west by carving out niches safe from the flames. They took root in inhospitable patches of habitat where the grasses that fueled the fires couldn’t grow—rocky surfaces and steep slopes with shallow soils and little moisture.

But beginning around 1870, settlers turned large numbers of cattle loose to eat the native grasses that grew among the sagebrush. This left less fuel for fire, and between this and a widespread campaign to suppress fires across the American West, soon nothing was keeping junipers confined to their steep, rocky sanctuaries. Now, when a robin perched on one of those gnarled branches to gulp a juniper berry, chances were good that the seeds would grow undisturbed wherever the bird happened to drop them. Across the region, juniper populations exploded.

Given the opportunity, juniper trees outcompete the grasses and shrubs of the sagebrush steppe. In extreme cases, nothing but bare soil and shallow-rooted invasive grasses remain between the trees, dramatically decreasing habitat quality for many species. Sagebrush-dependent songbirds like the Brewer’s sparrow (Spizella breweri) and the green-tailed towhee (Pipilo chlorurus) have nowhere to nest. Bighorn sheep (Ovis canadensis) and pronghorn antelope (Antilocapra americana) become more vulnerable to mountain lions (Puma concolor), which use junipers as cover to stalk large prey.

The spread of juniper can also reduce water availability in an already-parched landscape. Despite their drought tolerance, a single mature juniper can consume 10 to 30 gallons a day, pulling water from nearby streams and springs. While this affects native wildlife, it’s had an even greater impact on the cattle ranchers who for generations have come to depend on the sagebrush ecosystem’s natural resources. As water and native grasses become scarce, the number of cattle a piece of land can support plummets. Depending on the site and how advanced the juniper growth is, the tree’s invasion can decrease the amount of forage by 30 to 90 percent. The Oregon Cattlemen’s Association has called juniper “one of our most noxious invasive species.”

Still, no animal is more emblematic of the sagebrush steppe in trouble than the greater sage-grouse (Centrocercus urophasianus). These iconic western birds about the size of barnyard hens gather each spring in groups called “leks.” Here, the males inflate yellow air sacs in their chests, spread their fanlike tails, and dance for the approval and attention of the females—a display so show-stopping that many people have dubbed them America’s birds of paradise. Unfortunately, these reproductive spectacles have become increasingly rare as the species’ population has plummeted 80 percent since 1960, primarily due to habitat loss.

The sage-grouse is a kind of indicator species, signaling the health—or lack thereof—of the ecosystem it inhabits. As its name suggests, the sage-grouse depends on sagebrush for food and nesting cover. A number of factors in addition to the juniper invasion have contributed to the bird’s shrinking habitat, including energy development, invasive weeds, drought, and urban expansion. But juniper’s impacts on grouse go beyond the loss of sagebrush: Grouse have evolved to give a wide berth to any tree more than four feet tall, because anything taller than a sage bush represents a potential perch for a predatory hawk.

When mature juniper cover reaches just 4 percent—picture taking a standard checkerboard and filling in just two and a half of the squares—sage-grouse abandon their leks.

“If you think back to the 1980s, you had juniper encroachment occurring, but a lot of these stands hadn’t fully matured yet,” says BLM wildlife biologist Travis Miller. “As the juniper is maturing and encroaching further, our habitat is getting choked. You go up to a lot of these table tops where we count the birds at these leks and you just look around, and you see it basically becoming woodland,” he says. A native of Burns, Oregon, a hundred miles east of the Badlands, Miller spent his high school summers working for his father, Richard Miller, an Oregon State University professor who did some of the foundational research on sagebrush and juniper fire ecology. In the late 1990s, the father-son team cored and aged the 1,600-year-old juniper near the Badlands.

Today the younger Miller is responsible for monitoring the sage-grouse population in the agency’s Burns district, where large areas of land are in the process of being treated to slow or reverse juniper encroachment. His assessment is not optimistic. “Either sage-grouse need to adapt to juniper, or they’re going to be gone,” he says. Miller’s grim conclusion is based on the sheer scale of the problem, and the current slow rate at which these treatments are being conducted. “There’s a lot of leks with a lot of juniper,” he says. “It’s a daunting task.”