Since a number of people—especially those not living in the West—may not be very familiar with our peculiar slice of heaven called pinyon/juniper (p/j) habitat, a bit of description and some photos may be of interest.  This page covers 4 issues:  overview of p/j habitat in CO, information about the bark beetle infestations, cryptogamic soils, and the nest box environment on our property.  Click on any of these links to skip to that section.

Just to help orient you, here’s a map of CO, with some of the points I refer to below labeled, along with some of areas that non-Coloradans might also know.

Colorado geographic points

Colorado geographic points

SP = South Park (yes, that South Park!)     SLV = San Luis Valley


Colorado is estimated to have roughly 5 million acres of p/j habitat—a mere 7.5% of the state.  (You can see how unusual this lovely habitat is in the state on the map here.)  Annual precipitation typically ranges from 10 – 15 inches; here in Coaldale, we tend toward the lower end of that range most years.  In our particular area, we are in the “rain shadow” of the northern Sangre de Cristo Mountains; clouds gather moisture as they sweep across the San Luis Valley on the western side of the Sangres and wring it out as they cross the Sangres.  Little moisture remains in the clouds as they pass over Coaldale; but moving to the east, they again gather moisture to dump on the Wet Mountains to the east.  Characterized by hot summers, high winds, and intense sunlight, cloudy days are rare and the relative humidity is extremely low.  Rainstorms are infrequent but tend to be intense when they do occur; even just an hour of steady, gentle rain is something to celebrate.  The winters are often surprisingly mild—the area is one of several “banana belts” in CO.  Strong westerly downslope winds—called “chinook” or “snow-eater” winds—often warm the area and melt whatever snow may fall.  Even without these winds, the extremely dry air often causes lighter snows to simply evaporate rather than melt.  Soils in this habitat are often shallow, rocky, and at best only moderate in fertility.  The ground has little understory and a high proportion of bare soil.  Our soils are high in calcium carbonate (making for extremely hard water) and gypsum (with a gypsum mine about 1 mile from our house).

Referred to as “woodlands” rather than “forests” because the treesRocky Mountain Juniper rarely reach saw-millable size, p/j woodlands generally range in altitude from 4,500 – 7,500 feet.  Typically, lower-altitude p/j habitats have more junipers than pinyons; as altitude increases, the proportion of pinyons increases as well.  At our altitude of 7,000 feet, pinyon pines dominate—probably 90-95% of the conifers are pinyons.   This plethora of pinyons makes the junipers all the more precious.  We have 2 different species of juniper.   The silvery-green Rocky Mountain Juniper (left) is closely related to the Eastern Redcedar (which really is a juniper, despite its name), with beautiful red-streaked, aromatic wood well suited for cedar chests.  If you click on the photo to enlarge it and look closely, you can see berries on this tree.  The wintering Townsend’s Solitaires and American Robins are especially fond of these berries.

Oneseed Juniper

Oneseed Juniper

The yellow-green Oneseed Juniper (right) often has more than one trunk and can grow in wonderfully gnarly shapes.  Its name reflects the fact that its berries have only one seed, while other junipers usually have 2 or more seeds per berry.

As is typical for higher-altitude p/j habitats, our area has a significant shrub component of Gambel’s oak, mountain mahogany, three-leaf sumac, rabbitbrush, and sagebrush.  Just to highlight the peculiarity of the area, we also have several cactus species:  e.g., prickly pear, claret cup, yucca, and cholla.

Bark Beetle Infestations

Every so often, the bark beetle invasions of the western forests make the news.  To date, most of the bark beetle damage in CO has been west of the Continental Divide, decimating the majestic lodgepole pines of the high-altitude forests.   But in September 2008, a collective shiver ran through the cities of the Front Range (those in the urban corridor just east of the Rockies) when bark beetles were found throughout the Fort Collins area (the next major city north of Denver), primarily in non-native Scotch Pines but also in some native ponderosa pines.

It is estimated that CO has 23 million acres of forests; the bark beetle has already killed 1.5 – 2 million of those.  (It was news to me when I moved to CO to find that the national forests are a part of the Department of Agriculture—a powerful statement about their importance as a “crop.”)  In 2006, at least 40% of CO’s lodgepoles were infested; it’s surely higher than that now.  In some mountain areas, one looks out at areas that used to resonate with the deep, dark green of pines, only to find the reddish brown of dead lodgepoles as far as the eye can see.  Most of the lodgepole forests are found in north-central CO.  These beetle infestations can most cost-effectively be controlled by serious, extended cold—30 to 35 degrees below zero for a week or so.  But north-central CO has warmed to a greater degree over the last 50 years than has the rest of CO:  The state’s average low temperature rose by 2 degrees, while the average low temperature in north-central CO rose by more than 4 degrees.  Guess that’s all it takes…

Here in our little piece of central CO (probably about 30 miles east of the Continental Divide, as the beetle flies), we don’t have any lodgepoles and only an occasional ponderosa. (Our 40 acres have 1 lone ponderosa.  It doesn’t really belong, but it’s a grand tree.) Our predominant pine is the pinyon and our predominant insect anxiety is the ips beetle—ips confusus, I think.  About 19,000 acres of pinyons are infested with ips beetle in CO. We have some here, but it’s more an endemic situation than an epidemic situation (so far). The ips beetle is considered less aggressive than the mountain pine beetle (although don’t tell that to the Albuquerque area, which lost huge stands of pinyons, due to drought stress). The pinyons of southwestern CO have been seriously affected, I believe; here, though, we have been lucky so far to have had a couple of summers of decent (at least as far as pinyons are concerned) moisture and a couple of winters of surprisingly persistent snowpack. Our plants and soil know how to make the most of such bounties, meager though they may seem to people in other climates. That’s not to say we don’t have dead and dying pinyons—but they are the minority, thank heaven.

Cryptogamic Soils

One interesting aspect of our area is the large stretches of biological soil crusts (referred to colloquially as “cryptogamic”  or “microbiotic” soil).  Made up of living organisms such as cyanobacteria (formerly known as “blue-green algae”), mosses, and lichen—as well as their by-products—these fascinating crusts help to stabilize the soil and filter and retain precious moisture.  They are characterized by their dramatically increased surface topography, referred to as pinnacles or pedicles.  Frost heaves and uneven erosion result in the development of high pedicles.  Also, the organisms swell when wet and decrease in size when dehydrated, further increasing the surface area of the patches.  The rougher the surfaces, the greater the water filtration and retention.

Our 40 acres has about one quarter of an acre of this interesting soil.  Here are several photos of one of our cryptogamic areas.  From afar they appear barren and plain; but up close and personal, they seem rather other-worldly to me.

cryptogamic soil, view 1

cryptogamic soil, view 1

cryptogamic soil, view 2

cryptogamic soil, view 2

cryptogamic soil, close-up

cryptogamic soil, close-up

Although well adapted to severe growing conditions, these soils are extremely sensitive to compressions of almost any kind.  Here is a game trail worn by mule deer that we have now incorporated as part of our footpath system, in order to minimize any further damage to the area.  (And, as you can see, Paxi is very considerately sticking to the path himself.)

deer trail with blue heeler

deer trail with blue heeler

Nest Box Environment

To give you a sense of the context of our nest boxes in this interesting environment, Zell took photos of some of boxes from a more macro perspective.  You’ll note that all of the boxes are mounted on trees—a practice not recommended for all environments.  But, as I note elsewhere, our area has very few of the many nest box predators found in other areas:  raccoons, free-ranging domestic or feral house cats, tree squirrels, tree-climbing snakes, House Sparrows, European Starlings.  You’ll also note that the boxes are mounted rather low—none higher than 6 feet from the ground.  We used to have them mounted much higher in the trees, following the suggestions of many others.  But an ornithologist friend of ours was visiting once and mentioned that the boxes probably didn’t need to be that high.  We lowered them all posthaste and he was right.  The cavity nesters didn’t seem to mind at all and it certainly is easier for me to monitor and clean the boxes.  You can read more information about our nest boxes at nest box monitoring.

See if you can find the nest box in each photo (sort of a Where’s Waldo challenge).   You may need to click on each to see a larger version.

Facing due south, this photo shows box #2 with the foothills and some of the peaks of the Sangres in the far background.  (At the far left is Cottonwood Peak; next, an as-yet-unnamed ~12,500′ peak; then, the high point just to the left of the tree, The Nipple.  The Nipple marks the junction of 3 counties:  Frémont (where Coaldale is), Custer (to the south), and Saguache (to the southwest).)  You can also see the ubiquitous rabbitbrush, which provides vital food for deer and (not surprisingly) cottontails and jackrabbits during the winter.

Nest box #2

Looking southwest, box #4 features 1 of the Twin Sisters, with its summit above treeline in the background.  If you click on the photo to enlarge it—and look carefully—you can see that this box has a diamond-shaped entrance.  Zell adapted a couple of the nest boxes because he read that swallows might like that shape.  You can read more about this adaptation at the Violet-green Swallow write-up.  (Scroll to the bottom of that page for the write-up.)

Nest box #4

Nest box #4

This photo shows not only box #10 (and box #15 in the distance) but also Zell’s fuels mitigation work around the house.  Limbs up to 5 feet from the ground are removed and debris is raked up—all in an effort to limit the spread of wildfires traveling along the ground or spreading among low branches.  The effect is rather park-like, which is not necessarily my favorite look for this area.  But since there’s so little we can really do, it’s a small price to pay in an attempt to prevent total conflagrant destruction.

Nest box #10

A wonderful, old, twisted Oneseed Juniper hosts box #18.

Nest box #18

Box #19 is in one of my favorite locations (wisely selected by a VGSW pair this year—the “feather queen” of note in the VGSW write-up).  This box enjoys a gorgeous view of Bushnell Peak as well as both of the Twin Sisters.

Nest box #19

Resources consulted:







© 2008 Tina Mitchell


3 Responses to Habitat

  1. Hi Tina, I wrote to you a few years ago regarding American Dipper Birds. I’m still working on both my non-fiction about Sequoia National Park (thus the dipper nest-building email) and on a kid’s fiction novel about growing up in the Pike’s Peak area in 1898-1902. Just back from a research visit to Colorado, I’m sorry I didn’t make it to your ‘neck of the woods.” Whenever I visit, glad for your presence and your generous nature.

    Mary Martin Weyand
    Fillmore, CA

  2. Keith Kridler says:

    OH MY GOSH! To be able to walk out and check a nest box trail with the solitude that you have and the views and clear air that I can only dream about…The One Seed Juniper appears to be the same one that grows through out the Edwards Plateau area of Texas. This is one of the main food sources in central Texas for all three species of Bluebirds that winter in that region and also the many other species of fruit/berry eating birds.
    Thanks for sharing!
    Keith Kridler
    Mt. Pleasant, Texas

  3. Fread J. Loane says:

    Thank you for allowing me to freely roam your bit of Colorado heaven. With your well- chosen, guiding words, I swear I could smell the Pinyon air! Your abilities and writing talents are awesome. It is both such an honor and joy to share with you.
    Fread J. Loane
    Haskell, OK

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