Juniper Trees in our Area
Sources: Petrides, George & Olivia Petrides, 1992, A Field Guide to Western Trees, pp. 66-70, Houghton-Mifflin;
Our "Saguaro Juniper" Corporation is so named by virtue of the overlapping, intermingling presence of both Saguaro cacti (Cereus giganticus) and Juniper trees (Juniperus spp.) on some parts of our land. Some very large and beautiful junipers grow here, mostly around the 4,000 foot-level and on north-facing slopes, but quite a number (including some of the oldest) survive at near 3,000 feet elevation in well-protected (and exceptionally well-watered) washes.
Junipers are relatively small, slow-growing but long-lived trees (some surviving for more than a thousand years). During the Pleistocene Epoch, they were part of the pine-oak woodlands that were then the dominant vegetation complex in our area, but today we may regard them (at our elevations of 3,000 to just over 4,000 feet) as relics of cooler and winter-wetter times. We have noticed, in observing zones of overlap between Saguaros and Junipers here for over a decade, that we usually see very few young junipers in our uplands but a great many young saguaros, which suggests that over a somewhat long run Junipers are gradually retreating from and Saguaros colonizing these areas. (However, these patterns might be due to more short-term, perhaps cyclical, climatic changes.)
Junipers are usually found in dry climates. Like cedars and cypresses, they have small, scalelike leaves, but on at least some quickly growing twigs there are also sharp, needle-shaped leaves.
Our impression has been that nearly all of our resident Junipers are of the "One-seed Juniper" (Juniperus monosperma), but we're taking a humble stance at this time and admitting we haven't investigated them thoroughly enough to make general statements. We haven't seen an Alligator Juniper (Juniperus deppeana) yet. One of our landmark Junipers stands at the head of the Notch in our Notch Ridge & Basin just above the Waterfall. Here you see it at left -- a great shade tree for hikers wanting respite from the summer sun.
(Click on the image to enlarge it.)
This is a male tree, and we are unsure of its species, but below right you can see a closeup of its leaves:
This looks to us something like the "Utah Juniper" (J. osteosperma), by virtue of the generally short points of the leaf scales. (Click on the image to enlarge it.) But we need to learn more about details of comparison.
Junipers bear fleshy fruits (which are cones whose soft and thick scales have fused) containing from one to 12 seeds. The sexes of Juniper are mostly on separate plants, so identification requires locating female trees. The ball-shaped fruits are blue when young, darkening when they mature. They often show a whitish "bloom". Many birds and mammals eat the fruits (as did Native Americans and early pioneers).
The female members of junipers are fruit-bearing. This particular female tree, below,(in the Red Tank Wash), again, looks like Utah Juniper (Juniperus osteosperma) -- its leaf-scales are yellow-green and short-pointed, its mature fruits are reddish brown and single-seeded. But we should learn to examine these trees more carefully, and will do this as time permits. (Click on the image below left to enlarge it.)
Along the upper reaches of Red Tank Wash, there are a number of very large and old Juniper trees. Here are two, lying at elevations below 3,600 feet: (Click on the left-hand image for a close-up of the trunk.)
Junipers like these must be very old. At elevations of less than 3,600 feet, this is nearing the lower edge of Juniper distribution in our area, but these drainages are unusually well-watered, and we do see some fairly young junipers in this wash.
This one, below, lies on the edge of the Sierra Blanca Canyon Wash just below 3,900 feet (a wash area that also contains some young plants of the species). This one displays a very large root system spread, increasingly exposed as the banks of the wash erode (the visible roots extend just to the limits of each side of the photograph). (Click on the image for a close-up of the trunk.)
Here, below, along the upper edge of Jim's Willow Spring in Sierra Blanca Canyon Wash, is a juniper we might consider of "middle age": (Click on each image to enlarge it.)
This particular tree, which looks to us like Utah Juniper, was budding out above in January 2005, while the wash was still running from recent flood. It has an unusual shape for the junipers in our area -- low and spreading -- as shown below:
An Experiment with Mistletoe Removal
In Upper Cottonwood Seep Wash, in the canyon well below the seep stands an ancient juniper tree, located right in the middle of this fairly sizeable wash. Clearly it has endured the buffeting of innumerable gully-washing floods, yet it still survives with large rocks propped against it.
The three photos above were taken in 1997 and 1999, with a video camera, which was what we mainly used at this time and of poor resolution, so we include below some clearer illustrative images taken in January 2005 that display this tree as it should be seen: (Click on each image to enlarge it.)
The image above right suggests some major past episode of decapitation of a very old trunk, followed by resprouting at or near the base, with the subsequent growth of the (also now quite old) tree we see standing today.
One secret of the subsequent survival of this tree is evident in this 2005 image at right, showing the tree strongly bent in the downstream direction (toward the left in the photo), but sustained by a large rock which props it against the flood forces of the wash. This arrangement must be quite old. (The age of the tree could no doubt be measured by the rings in its trunk base, but in any case it must be very old despite its relatively small overall size.) (Click on the image to enlarge it.)
The photos below, again taken with the old video camera in October 1999, show how pervasively this tree had been invaded by mistletoe when we examined it at that time. A number of the upper branches were dead, and all of the others were covered with mistletoe growth, which is the main greenery visible in each of these photographs -- little chlorophyll energy is evident in the body of the juniper itself, whose leaves had a generally grayish cast .
So we decided to make an effort to extend the life of this tree, by trimming out as much of the mistletoe as we could find. We did this on one brief day in October 1999 (after the photos above were taken). It took less than an hour to remove all the visible infestations, leaving substantial piles of the parasite on the ground around the tree.
Returning in April, 2002, we found a much healthier looking Juniper, as you can see in the photograph to the right. A brief inspection showed no signs of mistletoe. We planned to continue monitoring this tree to see how our repair work stands up over time. (Click on the image to enlarge it.)
In January 2005, following good spring rains, we took the following pictures of the tree, below: (Click on each image to enlarge it.)
On the left, you see a rich growth of green leaves tinged with reddish growth, but now the reddish growth is almost entirely not mistletoe, but new sprouts. We do see some mistletoe which was missed by our 1999 pruning, and also some young mistletoe growth in places. For more details, see our page on Mistletoe.