Melting Glacier Exposes Frozen Forest
Laura Dattaro
Published: Sep 25, 2013, 8:30 AM EDT
weather.com
Researchers hope to find more vegetation on subsequent visits. (Cathy L. Connor)
The Mendenhall Glacier, which flows from the 1,500-square-mile Juneau Ice Field, has been retreating since the mid-1700s, according to the USDA Forest Service. But in the past 50 years, reports LiveScience, relics of an old forest
have begun appearing amid the melted ice. In the past year or so, trees
still upright and with roots and bits of bark still intact have been
exposed by the retreating flow.
Researchers based at the
University of Alaska Southeast (UAS) are studying the emerging forest;
they have determined that the trees’ ages range from about 1,200 to
2,350 years old, reports the Juneau Empire. The trees are likely spruce, UAS geology professor Cathy Connor said, though this hasn’t been verified.
"There
are a lot of them, and being in a growth position is exciting because
we can see the outermost part of the tree and count back to see how old
the tree was," Connor told LiveScience. "Mostly, people find chunks of
wood helter-skelter, but to see these intact upright is kind of cool."
The
trees were likely protected by a four-to-five-foot layer of gravel,
which spills out from streams of an advancing glacier’s meltwater in the
summer, according to LiveScience. The gravel protected the trees from
the glacier’s powerful motion, snapping branches and treetops as it
advanced.
Mendenhall is one of 38 large glaciers
originating in the Juneau Ice Field, nearly all of which are retreating.
Since 2005, LiveScience reports, the glacier has retreated about 170
feet per year, with an expected large retreat this year due to an
unusually warm summer.
So far, the Juneau Empire
reports, trees are the only remnants of the forest being exposed. But
the team hopes to find other vegetation to help better explain the
area’s history.
"These are relict stories, and piecing
them together with radiocarbon dating and stratigraphic work would help
piece together the chapters of the story," Connor told LiveScience.
MORE FROM WEATHER.COM: Glaciers In Retreat
Grinnell Glacier, Glacier National Park (1938 and 2009)
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