Monday, 26 February 2018

'Loneliest tree' records human epoch

Science correspondent
19 February 2018

It’s been dubbed "the loneliest tree on the planet" because of its remote location, but the Sitka spruce might represent something quite profound about the age in which we live.

The tree, sited on Campbell Island in the Southern Ocean, records in its wood a clear radioactive trace from the A-bomb tests of the 1950s and 60s.

As such, it could be the "golden spike" scientists are seeking to define the start of the Anthropocene Epoch - a new time segment in our geological history of Earth.

The suggestion is that whatever is taken as the golden spike, it should reflect the so-called "Great Acceleration" when human impacts on the planet suddenly intensified and became global in extent.

This occurs after WWII and is seen for example in the explosion in plastics production.

Chris Turney, from the University of New South Wales, Australia, and colleagues, say the Sitka spruce captures this change exquisitely in the chemistry of its growth rings.

"We're putting this forward as a serious contender to mark the start of the Anthropocene. It's got to be something that reflects a global signal," Prof Turney told BBC News.

"The problem with any Northern Hemisphere records is that they largely reflect where most major human activity has happened. But this Christmas tree records the far-reaching nature of that activity and we can't think of anywhere more remote than the Southern Ocean."



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