Piñon Pine — December 2008


Pinon lone tree

 In the midst of the Holiday Season, what better time to turn our attention to the most common needle-leaved tree on the Preserve and the official New Mexico state tree, the piñon pine?  Indeed the plant community type that dominates the Deer Canyon Preserve landscape is designated as piñon-juniper woodland.  Also known as New Mexico pine, nut pine, mesa pine, two-leaved pine, pinyon pine, Rocky Mountain pinyon, and pinón, the species Pinus edulis is undoubtedly the most abundant pine in the state and perhaps the entire Southwest as piñon-juniper woodlands occur on most dry mountain slopes, mesas, and plateaus at elevations between 5,000 and 8,500 feet.  It is fitting that the largest living piñon on record grows in Cuba, New Mexico and stands almost 70 feet tall with a trunk diameter of over 5.5 feet.  The oldest documented piñon was found in 1956 in northeast Utah and was 973 years old. 

 The piñon is a relatively short tree (usually 30-45 feet tall) with a rounded, dense crown that often spreads wider than the height of the tree.  The trunk and main branches are typically somewhat crooked and have a dark gray, rough bark with reddish irregular furrows.

  pinon bark

The tree grows slowly, usually taking about 180 years to produce a trunk of one foot in diameter; consequently the wood is quite hard and brittle resulting in a fuelwood that burns hot and slowly.  Piñons commonly grow to be 400-500 years old and may produce taproots that reach 20 feet deep.  Pine leaves (needles) grow in clusters called fascicles enclosed at the base by a tiny brown, paper-like sheath and piñon needles grow two/fascicle.  The needles are usually curved, somewhat blue-green in color, 1–2 inches long, with a lifespan of 4-6 years.

pinon male & female cones

 Piñons begin producing cones when they are around 25 years old with male and female parts located in different cones on the same tree, therefore the botanical term monoecious applies.  The male pollen-producing cones grow in clusters at the tips of twigs (a cluster of about 20 male cones appears in the upper right of the photo above).  Each male cone is about one-half inch long and yellow in color turning to red-brown.  Soon after releasing large amounts of pollen in May the male cones wither and drop from the twigs.  Female seed-producing cones are produced at the tips of other branches in much smaller numbers that the male cones (two young female cones may be seen in the upper left of the above photo).  Initially green in color, these female cones will receive pollen spread by the wind and begin a long, developmental process that requires over two years before the seeds (piñon nuts) are mature.  At that time (late summer of their second year) the highly resinous, rounded cones will be about 1.5-2 inches long with fully developed thick, woody cone scales each housing two mature seeds.  A single female cone may produce 10-20 brown, wingless seeds (one seed remains in the cone in the second photo below). 

 pinon seed cone

pinon cone w:nut

 

 Members of the pine family (Pinaceae) are trees characterized by needle- like leaves, resin-containing tissues, and male and female reproductive structures produced in separate cones on the same tree.  Four genera of the pine family are native to New Mexico; pines (Pinus) with 9 species, spruces (Picea) with 2 species, firs (Abies) with 2 species, and Douglas firs (Pseudotsuga) with 1 species.  The scientific name of piñon, Pinus edulis, means edible pine and indeed the seeds of this species are the largest and most nutritious of all pine seeds.  They have been collected and eaten either raw, ground, or roasted by the earliest Native Americans and continue to be prized today for their exquisite flavor as well as their nutritional value.  With a protein quality higher than any harvested nut except cashews, piñon seeds are also high in niacin and riboflavin.  Yielding 3,000 calories per pound, they are also harvested by numerous birds, notably scrub jays, and mammals, especially squirrels and chipmunks.  Perhaps as a mechanism to limit the population size of such nut-gathering species, piñons are known to have seed production cycles in which large quantities of seeds are produced by all trees in an area once every five or six years with minimal seed production in the intervening years. 

 In addition to the piñon’s value as a source of food, fuel, and construction material, its pitch has also been used traditionally as an antiseptic, and melted with red clay as a salve to soothe irritated skin.  The pitch is also used to waterproof containers such as baskets and clay bottles, and warm pitch may be applied as cement in crafting turquoise jewelry.  Mixing the resin with leaves of three-leaf sumac produces a black dye, whereas a yellow dye results from mixing piñon resin with lichens.  The resin (pitch) is useful to the tree in plugging up cracks or holes produced by weather and/or boring insects.  However in periods of extended drought piñons may become so stressed that they produce insufficient resin to plug all the holes and consequently become susceptible to insect infestations.  That appears to be the case in recent years in some areas of northern New Mexico where the Ips beetle has caused significant piñon mortality.   

 I am not aware of such beetle damage to piñons in our area, but the situation certainly bears watching (be on the lookout for small round holes in the bark).  There are plans for an experimental investigation to be conducted in a remote area of Deer Canyon Preserve by researchers from the University of New Mexico on the effect of the loss of adult piñons to the overall health of a piñon-juniper woodland.  This study is an effort to help scientists gain a better understanding of the consequences of major beetle infestations.  It is possible then, that the Preserve may contribute in some way to the status of the New Mexico state tree — so that the piñon may continue to nourish and comfort humans and a host of wildlife species long into the future.       

 

A Botanical View – Gymnosperms and Angiosperms 

 The more different plants one learns about, the more important plant classification becomes to help sort them out and understand their relationships.  Since piñon is the first non-flowering plant we have considered, now would be an appropriate time to consider the distinction between seed plants that flower and those that do not produce flowers.  Pines, like all gymnosperms, produced seeds in cones, whereas flowering plants (angiosperms) produce seeds that are completely enclosed in fruits that develop from flowers.  These are the two categories of seed-producing plants: the more ancient gymnosperms (the name means “naked seeds”) and the more recently-evolved angiosperms (plants with “covered seeds”).  

 Whether or not a seed is “naked” or “covered” has nothing to do with the presence of a seed coat.  All seeds have a protective outer coating that developmentally is part of the seed itself.  Seeds are considered “covered” when they are protected by a structure outside of the seed coat that completely surrounds them during the entire course of their development.  The end result of that protective covering is what botanists call a fruit.  All angiosperms produce some type of fruit structure.  Seeds are considered “naked” when they are not completely covered during the entire course of their development.  In most gymnosperms the structure that ultimately becomes the seed is not completely enclosed during the time that pollination occurs and usually the mature seed is exposed.  There is no fruit structure in a gymnosperm (and since the fruit develops from a flower, gymnosperms have no flowers).


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© 2008 Jerry Melaragno

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