Wednesday, June 16, 2010

Pinon Pines

Pinon pines do well in the dry, sunny climate of the Front Range and we have ten or so on our Littleton farm. Though some natural stands can be found as far north as Ft. Collins, these small, drought tolerant pines are best found on foothill shrublands south of the Palmer Divide, on lower slopes of the San Luis Valley and across the lower foothills and mesa walls of the Colorado Plateau. Favoring sun-exposed areas between elevations of 5000 and 8000 feet, pinon pines form open woodlands with a variety of western junipers; drought tolerant shrubs, such as mountain mahogany, greasewood, bitterbrush and serviceberry, also characterize this life zone, which receives 10-20 inches of annual precipitation (most in the form of snow melt).

Easily recognized by their small, rounded shape (usually under 30 feet in height) and short needles in bundles of two, pinon pines bear female and male cones on the same tree. A deep tap root enables these trees to thrive in their semiarid environment and potent resins protect them from browsers and insects. The small female cones ripen to produce two large seeds on each scale, a favored food of humans and wildlife alike.

Like the oak forests of eastern North America, these pinon woodlands rely on scavengers to spread their seed. Taking the place of eastern gray and fox squirrels are Clark's nutcrackers, Steller's jays, scrub jays and pinon jays. These birds busily cache the pinon seeds in late summer and early autumn, often carrying them a mile or more from the parent tree. Since, like the squirrels, these birds bury more seed than they will ever consume, the future of the pinon pine woodland is assured. In addition, like the oaks, pinon pines produce mast crops every 5-7 years, further ensuring the survival of these attractive trees.