One–seed Juniper — February 2009

Juniper tree1


Late winter is a time when many are reminded of one-seed juniper (Juniperus monosperma), not just because it is easily the most abundant tree on the Preserve, but also because the air fills with juniper pollen for a couple weeks sometime between late February and late March.  Juniperus is an old Latin word for this type of tree and monosperma means one seed, so the scientific name of this plant is the same as its common name.  This species is sometimes also called cherrystone juniper, New Mexico cedar, or Sabina (a Spanish word for juniper).  It thrives in dry, rocky soil up to an elevation of about 7,000 feet.

One-seed juniper is a slow growing, long-lived tree that usually reaches a height of 10–20 feet.  The largest one on record is found in New Mexico, in the 

Jicarilla Mountains northeast of Alamagordo, and is 29 feet tall with a trunk circumference of 168 inches and a crown spread of 28 feet.  Juniper trunks are frequently branched near the base and have gray-brown bark that detaches in long thin strips revealing a cinnamon color under the bark.  The root systems of junipers often grow deep taproots giving the trees access to water that is not available to neighboring plants.  Unlike many conifers, juniper leaves are scalelike, rather than needlelike.  In fact, junipers are characterized by having two types of leaves.  Most of the leaves are small and flattened with tiny glands that produce a white exudate.  Leaves at the tips of some branches are twice as long as the scalelike leaves and sharply pointed, like tiny awls, making new branches prickly to the touch.

Juniper male cones2

Junipers also differ from other conifers in that their seed cones are small and spherical with fleshy outer scales; consequently they are often called berries (although botanically, they are not fruits).  Like other conifers junipers have separate male and female cones, but unlike pines the cones are produced on separate trees (the dioecious condition).  The male trees produce small pollen cones in large numbers, and release pollen in the late winter or early spring.  The female cones of one-seed juniper are also quite small and typically develop a single seed, although two or three seeds may form in rare cases.  By the fall, the seeds are fully developed and surrounded by the fleshy scales making the “berry” which measures about blue whereupon they are typically eaten by a variety of birds and mammals, a most effective means of seed dispersal.

Juniper female cones3

Juniperus monosperma was a true multipurpose plant for Native Americans.  The wood is extremely rot-resistant making it good for construction and for fuel.  That same property may be why it was preferred for rites associated with funerals such as fumigating homes to expel evil spirits after a death, and to fumigate the deceased’s property.  Berries were used to season meats and stews or roasted in a deer stomach.  They were also strung as beads and used in children’s rattle toys.  Juniper charcoal was mixed with chewed melon seeds to produce body paint.  Finely shredded bark is said to have been the earliest diaper material.  And there are a host of medicinal uses such as: infusion of the male cones for stomach problems, leaf infusions to ease childbirth and treat colds and aches, and chewed bark for spider bites and other wounds.

Juniper bark3

One-seed juniper is widely considered to be a weed tree because it grows just about everywhere (I see that as a testament to its adaptability and its seed dispersal strategy) and it is bad-mouthed for using a lot of water.  However from my recollection of plant physiology I cannot think of any reason why junipers would use more water than any comparable tree such as piñon and they certainly don’t use as much water during the growing season as broad-leaved trees like the non-native Siberian elm or the Tree-of-Heaven.  Furthermore water that passes through trees is not necessarily lost to the ecosystem, in fact some is passed directly to various herbivores.  I certainly understand that junipers are unwanted in rangeland where they frequently turn up and are a pain to remove.  And junipers tend to grow together forming thickets with lots of dead trunks and branches that become a significant fire hazard.  In our fire-prone territory thinning and removal of dead wood is certainly necessary especially in areas near homes and other structures.

Rather than regard it as the poor sister in the piñon-juniper woodland plant association that dominates the Preserve, I would place one-seed juniper at least on par with its partner piñon pine.  Both tree species are critical to maintaining the stability of our woodland system.  Both provide food, protective cover, nesting sites, and water to dozens of wildlife species.  Junipers, perhaps more so than pines, create a suitable habitat for the growth of other plants.  For example, I find it much more common to see a small piñon growing at the base of a juniper than vice versa.  And there are several of our showy wildflowers that are much more likely to thrive growing at the base of a juniper tree than out in the open.  Along those same lines, when I walk my dogs they spend a lot more time sniffing around juniper trees than they do in open areas of the Preserve.  So let us appreciate one-seed juniper for the critical role it plays in nurturing the many other organisms that are vital parts of web of life around us.

A Botanical View – Are junipers and cedars the same tree?

It is very common to hear one-seed juniper, and other juniper species being called cedars.  In common parlance there is nothing wrong with this practice.  As long as the common name of an organism is effective in distinguishing one type of organism from another there is nothing wrong with that usage.  It is certainly the case that almost all plants have more than one common name.  If the person or persons you are talking to understand the type of tree you mean when you say cedar, then it is certainly appropriate to use that name.

To a botanist, however, calling a juniper a cedar is clearly incorrect.  Botanists recognize junipers as trees that belong to the genus Juniperus.  This genus is part of the Cupressaceae (the cypress or redwood family) and is characterized by scalelike leaves and fleshy cones.  There are over 60 different species of junipers worldwide of which seven are native to New Mexico.  True cedars belong to the genus Cedrus which is part of the pine family (Pinaceae) and has woody cones.  All species of Cedrus (such as the famous Cedar of Lebanon, Cedrus libani) are native to Asia or North Africa.  Whereas both junipers and cedars belong to the same major plant group, conifers, they are members of distinctly different families making them quite different types of trees.

Why then is it so common for non-scientists to refer to junipers as cedars?

Probably because juniper wood and cedar wood are quite similar and are used for similar purposes.  The heartwood of both cedars and junipers is red colored and highly aromatic, filled with chemicals that make it highly resistant to decay.  And since there are no true cedar trees native to the Western Hemisphere, when someone calls a tree a cedar around here much of the potential confusion is moot.  Indeed the most widely accepted common name for Juniperus virginiana, the juniper I encountered most frequently in Rhode Island, is eastern red cedar.  So feel free to use the names juniper and cedar interchangeably, and understand that my botanical training requires that I avoid using the name cedar for a juniper without a caveat.


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© 2009 Jerry Melaragno

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