Recreational Activities - Ancient Bristlecone Pine Forest
Your Visit to the Bristlecone Pine Forest
![[Photo]: Bristlecone Pine Forest Visitors Center](images/drama.jpg)
Ancient Bristlecone Pine
Land of the Ancients - The
Trees that Rewrote History
Standing as ancient sentinels
high atop the White Mountains of the Inyo National Forest, the Great
Basin Bristlecone Pines rank as the oldest trees in the world and
have achieved immense scientific, cultural and scenic importance.
While the oldest trees are found in the mountains of Eastern California,
Great Basin Bristlecone Pine (Pinus longaeva) are scattered throughout
the high mountain regions of Nevada and to a lesser extent, Utah.
A cousin, the Rocky Mountain Bristlecone Pine (Pinus aristata),
is located throughout the eastern Rocky Mountain region in Colorado
and New Mexico. An isolated population of the aristata is also located
near Flagstaff, Arizona. A third member of the bristlecone pine
family, the Sierra Foxtail pine (Pinus balfouriana) is located in
the southern Sierra range and in isolated groves in northern California.
Originally classified as a foxtail pine because of the needle arrangement
(like a cat or fox's tail), these trees were redesignated
in the late 1800's and named bristlecone due to the long prickly
"bristle" on the immature cone. In 1963, Dr. Dana K. Bailey
determined that there were significant genetic and physical differences
between the bristlecones in the Great Basin and those in the Rocky
Mountains. His research efforts resulted in another redesignation
into two separate species named bristlecone: the Rocky Mountain
Bristlecone Pine and the Great Basin Bristlecone Pine.
In
the White Mountains, the ancient bristlecone pines seem to show
a preference for growing on the white, rocky soil that gives the
name to this mountain range.
This is Dolomite, a type of limestone created under the warm,
shallow, inland sea that once covered this area. This Dolomite is
very alkaline in soil chemistry and thus makes for very challenging
growing conditions: precisely why the oldest trees are found here.
The bristlecone pines don't actually "prefer" this
soil type. Other plant species have a very difficult time growing
in it and the bristlecones, because they have adapted to this high
alkalinity, have a chance to get established and grow in a near
competition-free environment. In other areas, such as the Great
Basin National Park, bristlecones have established themselves on
soil types that are equally inhospitable to all but the most hearty
of survivors: the ancient bristlecone pines
Every year, trees produce a new layer of wood just under the bark.
During a dormant period, or time of slower growth, a narrow band
of dark wood is produced which when added to the lighter colored
"summer growth", produces what we see as a distinguishable
tree ring. In wet years, the width of this layer of new wood is
usually wider than in years of drought. The bristlecone pines are
known as great recorders of these climatic variances due to their
high sensitivity to changes in annual precipitation. Scientists
who study and research tree-ring patterns are known as dendrochronologists;
they are called dendroclimatologists if they specialize in climate
research through tree-ring records.
Researchers use a device called an increment borer to extract
a small cross-section of a tree. This sample provides a look at
each tree ring and enables scientists to determine both the age
of the tree and the pattern of its growth. There are many trees
in the bristlecone pine forest of the White Mountains that exceed
4000 years of age, and are still growing!
Bristlecone
pine wood that has fallen to the ground can remain intact for thousands
of years in the cold, dry climate of the White Mountains. Using
a cross-dating technique that overlaps tree-ring patterns of living
trees with the still intact patterns of dead wood, scientists have
assembled a continuous tree-ring chronology extending nearly 10,000
years. This bristlecone pine chronology, developed here in the White
Mountains by University of Arizona researchers and Dr. Henry Michael
of the University of Pennsylvania is the longest in the world and
provides an unequaled look into past climatic and environmental
conditions.
For many years now, scientists, archeologists, and historians have
relied on a dating system known as radiocarbon dating. It was discovered
back in the 1960's that this process was flawed and needed
to be calibrated. The wood from bristlecone pines helped correct
this process by providing samples that could be precisely dated.
Scientists dated these samples by counting their growth rings; they
then measured the amount of carbon-14 (C-14) in those same samples.
They discovered that the radiocarbon dating process was providing
dates that were "too young" and established a calibration
factor to correct the dating process.
Faulty C-14 data obtained before the bristlecone pine calibration
was then re-examined and corrected. Archeologists found that some
artifacts discovered in Europe were actually 1000 years or older
than previously thought. This revision of archeological site dates
led historians to a reinterpretation of cultural diffusion throughout
the Mediterranean and European areas. Because the bristlecone pines
of this grove provided the wood to recalibrate the radiocarbon dating
method, they have become known as the trees that rewrote history.
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