SCIENCE LAB SCARES : CALAMITY IN WAITING [ 2 ]

IN the 1990s, Patrick Pringle, now a geologist at Centralia College, took samples of wood from an enormous tree stump in a freshly dug construction pit.

For roughly a decade, Mr. Pringle's team collected wood from trees at construction sites.

Dr. Black recently analyzed the wood from 21 of those trees, all Douglas firs, and assembled a tree-ring record spanning 475 years.

Dr. Black's team compared that record with a Data set of old living Douglas trees on Vancouver Island in British Columbia, 150 miles away. Because those trees were still living, their rings can be precisely age dated.

By matching Vancouver Island and Orting records, calendar years could be assigned to Orting tree rings.

Four Orting trees showed evidence of having bark, meaning their outer rings were the last to ever grew.  And those trees all died in 1507 - the year of the Electron Mudflow, preserved in entombed lumber.

'' We took what was a fuzzy uncertainty and now pretty much put a razor blade on that timing,'' Dr. Black said.

The World Students Society thanks Katherine Kornei.