The Great Basin bristlecone pine (Pinus longaeva,) Nevada's
state tree, includes the oldest living trees in the world (maximum recorded age
of 4,844 years.) This species is characteristic of the subalpine zone in some
Great Basin mountain ranges where it is the dominant tree species along with
limber pine (Pinus flexilis). Present in many of the high ranges of Eastern
Nevada, it is absent from most of Central Nevada west of the Monitor Range and
from the northern ranges. Although the tree is widely distributed across an
elevation of 6,760–11,600 feet, the oldest trees are found in harsh,
high-elevation environments in the White Mountains and the Snake Range.
Excellent hikes can be taken through ancient groves of this species in Great
Basin National Park.
Bristlecone pine is famous for its gnarly, twisted,
contorted growth forms. Slow growth of the resinous wood causes its resistance
to insects and disease, while the stressful environments where it grows limit
the potential for wildfire spread, thus allowing this species to reach great
ages. The oldest trees adopt a "strip-bark" growth form in which narrow strips
of living inner bark carry water to the surviving branches and return nutrients
to the roots. The great majority of the tree is, in fact, dead, provoking Ronald
Lanner, an authority on the bristlecone pine, to point out that the question is
not why these trees "live so long," but why they "take so long to die."
In addition to their aesthetic value, bristlecone pines have
made a major contribution to our scientific understanding of historical climate
conditions. Using dendrochronology,
it is possible to compare tree rings of living trees with those of dead trees
that have persisted for millennia as snags or logs in these high-elevation
environments. In this way, tree-ring chronologies have been reconstructed that
provide information about historical climates dating to earlier than 6000 B.C.
Suggested Reading:
David A. Charlet. Atlas of Nevada Conifers: A Phytogeographic Reference. Reno: University of Nevada Press, 1996.
Ronald M. Lanner. Trees of the Great Basin: A Natural History. Reno: University of Nevada Press, 1983.
