A U.S. scientist studying the dramatic change in ice conditions in B.C.'s Coast Mountains has discovered freshly exposed and perfectly preserved tree stumps -- some 7,000 years old -- an "astonishing" sign of how fast and far the glaciers of Western Canada are retreating in the age of climate change.
The stumps -- found at the foot of a melting glacier in Garibaldi Provincial Park, about 60 kilometres north of Vancouver -- were "still rooted to their original soil" and in such pristine condition that some had retained their bark, says geologist Johannes Koch, a former Simon Fraser University researcher now with Ohio's College of Wooster.
The stumps are relics of an ancient forest that was growing when humans were still relatively new arrivals in the Americas. At the time, Garibaldi's advancing Overlord Glacier overran the trees and encased their dead remains in an icy tomb that eventually reached hundreds of metres in depth.
The glacier would have advanced and retreated many times over the ensuing 7,000 years. But never, notes Koch, had historical warming cycles shrunk Overlord enough to release these trunks from their primeval deep-freeze -- until now.
"The appearance of this wood indicates that glaciers are becoming much smaller," Koch told CanWest News Service, adding that the stumps' exposure is a strong indicator that "the climate we observe these days is rather unique -- especially considering the pace of change in the past 150 to 200 years is astonishing."
The age of the stumps was measured using radiocarbon dating of samples from the newly exposed wood. The findings, presented recently at a Denver conference of the Geological Society of America, echo similar studies of glacial retreat in the Yukon, Europe, South America and New Zealand, said Koch.Times Colonist
