BOSH Project Destroys Tens of Thousands Acres of Juniper

Juniper removeal in Owyhee Mountains, Idaho. Photo George Wuerthner

The BOSH project in southern Idaho ultimately plans to destroy tens of thousands of acres of juniper woodlands on BLM lands. BOSH stands for Bruneau-Owyhee Sagebrush Habitat Project.

Snow covered juniper at Stinkingwater Pass, Oregon Photo George Wuerthner

The advocates of the BOSH project use pejorative language to characterize the Juniper clearing from the landscape. Terms like “restoring” the “natural” condition of the land assume that the lack of Juniper is the “natural” situation. Suggestions that Juniper is an “invader” and “encroaching” convey that juniper expansion is abnormal and difficult to manage.

Juniper woodlands, Owyhee Mountains, Idaho. Photo George Wuerthner

Ironically, the BOSH video discusses how creeks and springs are restored by eliminating Juniper. Still, in every area shown in the video, the riparian areas are heavily grazed with streams, wide and shallow from cattle use.

Bunchgrass under juniper. In areas without livestock, native bunchgrasses often are found growing beneath juniper. Photo George Wuerthner

Juniper are a native species that play an important ecological and ecosystem role in western arid lands. However, federal and state agencies, often acting as minions to the livestock industry, characterize the tree as an “invader” that must be controlled. Not surprisingly, most ranchers and their agency lackeys believe Juniper should be eradicated from many parts of the West.

The BLM claims the BOSH project is the largest “restoration” effort ever undertaken in the sagebrush steppe. The idea that removing tens of thousands of native trees is “restoration” itself demonstrates the biased nature of these projects.

The BOSH juniper removal is justified as a mechanism that will imrpove sage grouse habitat. Photo George Wuerthner

 Like many other juniper removal programs, the BOSH project is justified in the name of sage grouse recovery. After all, who isn’t for restoring sage grouse populations?

According to the BLM, 30,000 acres of land are being “treated’ (read logged) yearly to “halt juniper encroachment.’ So far, 140,000 acres of sagebrush steppe have been degraded.

Juniper cut by chainsaws. Photo George Wuerthner

The underlying assumptions about juniper “encroachment” are seldom questioned, and the science behind these disastrous practices is not subject to scrutiny.

Note that the juniper is common on the slope but has not been able to colonize the flatter ground more suitable for sage grouse. Photo George Wuerthner

For one thing, most juniper “encroachment” occurs on steeper terrain that sage grouse utilize less. I’ve seen many areas where Juniper is growing on mountainsides and slopes, but it is not happening in the flatter areas that are prime habitats for sage grouse.

Relict native bunchgrass surrounded by exotic cheatgrass in Owyhee Mountains, Idaho. The flammable cheatgrass is burns out sagebrush and is one of the biggest threats to sage grouse. Photo George Wuerthner

The BOSH project burns Juniper, often resulting in cheatgrass invasion in these disturbed sites.

The BOSH project relies on research from the Warner Mountains in SE Oregon. The study documented that within three years, a third of marked sage grouse nested in restored sagebrush habitat. In addition, nest success increased by 19% once trees were cut.

As a result, the sage grouse population in the restored areas grew at a rate that was 12% higher than those in neighboring areas with trees.

However, as the authors of this paper point out: “To our knowledge, our study is the first

empirical evidence of a population-level benefit for sage-grouse from habitat management.”

While I do not doubt their conclusions, it behooves the BLM to do additional confirmation of the conclusion that massive juniper removal truly benefits sage grouse survival before destroying hundreds of thousands of acres of Juniper based on one study.

Catte impacting water source in Owyhee Mountains, Idaho. Photo George Wuerthner

One of the basic assumptions behind juniper removal is that it will eliminate perches for sage grouse avian predators like ravens. Nevertheless, their paper showed that a reduction in avian predator perch sites and hunting efficiency was not a factor in chick survival. Instead, they: “speculate that juniper removals may not have benefited chick survival as much as other vital rates.” They conclude that primary predators of chicks in the project area may not be avian and were not affected by the removal.”

However, it’s important to note that federal and state agencies are using sage grouse as the justification for eliminating a native species (Juniper) that only occurs sporadically in prime sage grouse habitat while ignoring the multiple ways that the far more widespread effects of livestock grazing hinder sage grouse recovery.

Owyhee Mountains, Idaho, Photo George Wuerthner

Juniper has indeed expanded its range in many places. The reasons for this vary, including livestock grazing, climate change, and other factors. Whether this is an “invasion” or natural range expansion is critical to understanding the issue.

The agencies and the ranching industry see junipers as invaders and undesirable because they assert that junipers reduce the grass upon which their cattle graze. However, in places without livestock, grass growth is often abundant in the understory of juniper woodlands.

It’s important to note that juniper ecosystems have expanded in some areas and declined in others. Furthermore, many areas targeted for juniper removal are not prime sage grouse habitats. Instead, sage grouse is used as an excuse to eliminate a tree that the ranching community sees as a threat.

Old growth juniper store a considerable amount of carbon. Photo George Wuerthner

Here is where the conflict over different environmental goals comes into conflict. Two years ago, President Biden issued Executive Order #14072, which established a policy to conserve mature and old-growth forests, including Juniper.

Juniper can live for more than a thousand years and hold a lot of carbon, thus helping to reduce CO2 in the atmosphere.

Juniper berries are an important food source for many birds. Photo George Wuerthner

In addition, Juniper is an important species for wildlife. Juniper woodlands are used as hiding cover and shelter for mule deer and elk. Many bird species nest and take shelter in Juniper. Sixty species of birds consume the berries.

Some studies conclude that the Juniper is partly shifting its range due to climate change. Suppose such range expansion is due to natural causes, which began long before the more recent climate warming induced by humans. For instance, pinyon-juniper did not expand broadly until ~ 700 cal yr BP. Increased fire-related deposition coincided with regional droughts and pinyon-juniper infilling ~ 850–700 and 550–400 cal yr. Such natural expansions are continuing today.

Note the abundance of grass growing among juniper in this cow-free area. Most range scientists haven’t seen cow-free areas, so they conclude juniper inhibits grass growth. Photo George Wuerthner

Another study in southern Idaho at the northern edge of the pinyon-juniper range documented that infilling, rather than outright expansion, was the most common feature of these woodlands. The study revealed that woodland cover remained at approximately 20% of the area over the 59 years of the research. In the absence of disturbance, P-J woodlands exhibited the highest rate of increase among vegetation types at 0.37% per year.  

Another study in southern Utah that cored juniper found the ages varied from 160 to 3375 years, demonstrating that the so-called juniper “invasion” was not due to fire suppression or other factors usually given for the presence of juniper.

Juniper has shrunk and expanded many times in the past 4000 years as a consequence of changing climate conditions. Photo George Wuerthner

As Belsky argues from a viewpoint in the Journal of Range Management, “During the periods 4000-2000 before present, juniper expanded and contracted several times in response to increasingly mesic or set-k conditions, respectively, and occurred over areas often greater than those of today.

Belsky also challenges the common assertion that juniper reduces water flows and infiltration.

Cattle trashed riparian area. Cattle impact watersheds far more than juniper, compacting soils, removing streamside vegetation, and creating shallow, wide streams. Riparian areas are critical to sage grouse chicks. Photo George Wuerthner

While juniper removal appears to positively impact sage grouse survival, juniper colonization is typically marginal sage grouse habitat.

Other factors like the loss of sagebrush due to wildfire (enhanced by cheatgrass invasion), livestock consumption of forbs needed by sage grouse chicks, the destruction of riparian and wetland areas utilized as essential habitat by sage grouse chicks, and fences that are a significant source of mortality for sage grouse adults.

Livestock production is a major contributor to sage grouse decline. Photo George Wuerthner


The root cause of sage grouse decline is directly linked to livestock impacts. Far more of the range of sage grouse is occupied by livestock grazing than the area affected by any juniper expansion. Therefore, if agencies were genuinely interested in sage grouse recovery, they would focus on the activity that is the greatest threat to sage grouse survival, which is livestock production.

Grazing by livestock eliminates much of the grass understory where Juniper occurs, reducing competition for water, nutrients, and light.

Biocrusts protect soil from erosion and can inhibit seedlng establishment of cheatgrass. Such crusts are trampled by cattle hooves. Photo George Wuerthner

Cattle trampling of soil crust creates the disturbed soil necessary for juniper seedling establishment. Biocrust may also limit wildfire spread.

Furthermore, cattle trampling of biocrusts increases the likelihood of cheatgrass invasion. Cheatgrass is an annual grass that dries out earlier than native grasses and is fire-prone. Cheatgrass invasion, by increasing wildfire in sagebrush ecosystems, is a far greater threat to sage grouse survival than Juniper.

Another impact of western livestock production has been the conversion of many valleys into irrigated hay fields for livestock forage production. Hayfields typically are created by the removal of native vegetation, including sagebrush, planting of non-native grasses like alfalfa, and use of water that is often removed from natural water sources, thus shrinking or eliminating wet meadows and riparian habitat essential to sage grouse survival.

Sage grouse are poor fliers, and typically fly low to the ground where they often collide with fences. In some areas, fence collisions are a major source of morality. And the only reason we have fences across much of the Sagebrush Steppe is to facilitate livestock produciton. Photo George Wuerthner

Sage grouse are poor fliers and avoid flying across open hayfields without hiding cover (defined as shrubs like sagebrush); hence, such agricultural grounds fragment sage grouse populations and habitats.


Fire suppression is sometimes identified as a factor in juniper expansion, but this is based on a misinterpretation of sagebrush fire regimes, which I will address briefly. Almost all juniper expansion papers cite Miller, etc., in 2005, with an incorrect conclusion that fire suppression is the primary cause of juniper expansion.

The starting assumption of range professors like Miller and range managers tend to believe sagebrush burned frequently—usually less than twenty years. Since then, almost all research on Juniper cites the Miller paper to explain juniper expansion. The paper about the Warner Mountains repeats the old line that fire suppression has led to juniper expansion.  

Sagebrush has no adaptation to wildfire. It is killed by frequent fire. Photo George Wuerthner

The logic goes something like this: if sagebrush were burning frequently every 10-20 years, often attributed to Native American burning,  it would quickly kill any juniper expansion since Juniper is not tolerant of wildfire. However, as Baker points out in his paper on Juniper, there has been almost no fire scar research on Juniper itself, and the assumption that sagebrush is characterized by frequent fire has been debunked. Instead, high-severity blazes at long rotations characterize juniper woodlands.

However, the flaw in this logic is that sagebrush has no adaptations for fire tolerance and is easily killed by flames. If fires were as common as every 10-20 years, we would not have any sagebrush or sagebrush obligates species like sage grouse.

The fire rotation of sagebrush varies with the sagebrush species but is between 50 and 400 years. So, fire suppression, which at best has been effective for only 50-100 years, could not explain juniper expansion.

Juniper tend to burn at high severity on long fire rotations of hundreds of years. Photo George Wuerthner

Juniper tends to have long fire rotations in the hundreds of years and tends to burn at high severity where the trees are killed. Stand-replacing wildfire is driven far more by weather and topography, not canopy fuels.

Removing Juniper tends to accelerate colonization by exotic annual cheatgrass. The weeds (cheatgrass) that often replace Juniper are fuels that are more flammable and are one of the critical reasons for loss of sagebrush steppe across the West.

The Voluntary Grazing Permit Retirement Act could remove livestock from much of the sage grouse habitat with far better consequences for the bird than destroying tens of thousands of acres of juniper. George Wuerthner


Removal of livestock grazing would have a far greater impact on sage grouse survival than destroying tens of thousands of acres of Juniper. The Voluntary Grazing Permit Retirement Act is one mechanism that can help reduce livestock impacts on sage grouse. The Act has been introduced into Congress a number of times, but thus far has not been enacted.


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George Wuerthner is an ecologist and writer who has published 38 books on various topics related to environmental and natural history. He has visited over 400 designated wilderness areas and over 200 national park units.

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George Wuerthner