A Slice of History

Scientist have named it, dendrochronology: the dating and study of tree rings. But that

is a terribly boring word for something that embodies such artistic beauty.

The amature historians, ecologists and Jr. Ranger Rick's all know each year of a tree's growth produces a new ring around the outermost layer of the trunk. The rings are separated by light and dark wood to denote the moisture and temperature of the growing period. The wider the light colored ring, the more optimal (wetter) the environment was for a particular tree or species of tree. It's fascinating to play detective on a fallen tree.


Scientists even have a way to find the number and width of tree rings without harming the tree. With the use of a tool called an increment borer, scientists quite literally bore a small hole in the side of a tree and remove a sample of the cross-section. The living tree is able to heal itself by filling the hole with resin.


Surprisingly, Washington State is one of

two states that does not have a state coordinator to find, track and keep current records on important trees (Keeper's of the Trees). In fact, our oldest tree, aptly named Big Tree, died a quiet, largely unnoticed death in 2015. The approximately 250 to 500 year old Ponderosa Pine near the Columbia River Gorge now has such significant rot in its core that is would be impossible to study its rings.


Luckily, recent history has provided some tree ring research. Two paleoclimatologists at the University of North Carolina published a fascinating scientific report on Ponderosa Pines of the Pacific Northwest. Their findings have tracked storms between the Pacific


Ocean and the Cascade Mountains over the past 325 years using increment boring. Unlike traditional dendrochronology, which focuses on specific events in the our climate's past, this research shows an overall eb and flow of weather. Prior to the research, modern meteorological records beginning in the 1950s had shown an increase in PNW wet weather-- something any Washingtonian would affirm. But this tree ring analysis has given us an extended 250 year view into the past. And as it turns out, our stereotypically wet weather is in fact on a return to it's historically average levels. Not sure if that's an uplifting note to end on, but perhaps that means sunny days ahead!

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