Geoscience Reference
In-Depth Information
precipitation each year, most of it as winter snow. But even with such adverse
conditions, the bristlecone pine survives and reaches extremely old age.
Subsequent research has shown that the harsh conditions and extreme age
of the trees are related. h e slow growth rate of the bristlecone pine—with
100 tree rings in one inch of trunk—means that its bark is extremely dense,
making it resistant to rot, fungi, insects, and erosion. h e dense bark is
thought to be the primary reason these trees can live i t y times longer than
most other living things.
Ye a r s a t er this memorable hike into the bristlecone forest, Powell would
remember with fondness his summer working with Schulman, the i rst sci-
entist to recognize the importance of bristlecone pines for climate research.
Schulman was an expert in the then-new i eld called dendrochronology—
using tree growth rings to re-create a timeline of climate information. He
had spent much of his career searching for ancient trees that could provide
a means to study climates deeper and deeper into the past. His search
eventually brought him to the White Mountains, where local park rang-
ers talked about the gnarled pine trees that looked very old. At er years of
work, Schulman i nally found and dated the oldest tree in the grove, which
he named Methuselah. h
is tree is more than 4,800 years old—and still
alive today.
Powell recalled conversations he had with Schulman around the camp-
i re that summer. One evening in particular, the discussion took an oddly
unscientii c turn. Schulman talked about the trees as if they possessed the
secret to longevity, and he wondered aloud about the possibility of distilling
from these ancient trees an elixir of life. Not long at er this summer i eld
season, Schulman died of heart disease at age forty-nine. Although he did not
discover an elixir of eternal life for himself, the trees he studied have shared
their memories with scientists—memories of long droughts and periods of
abundant rainfall over the millennia. By carefully linking the tree-ring pat-
terns in dead trees with those of live ones, subsequent researchers have been
able to extend the bristlecone tree-ring records back almost 10,000 years.
Trees have proven to be a powerful tool for paleoclimatologists, largely
because they respond every year to conditions of temperature and precipita-
tion, and their responses are recorded in the growth rings of their trunks.
Schulman learned this in the 1930s as a protégé of one of the great tree-ring
pioneers, A. E. Douglass of the Tree-Ring Laboratory at the University of
Arizona in Tucson. Douglass had recognized that long-lived trees, especially
those in drought-prone areas like Arizona in the Southwest, could provide
