Environmental security

How a bizarre Nazi military machine left a lasting mark on the environment

The Tirpitz was the Nazis' most imposing warship and the largest battleship ever built by a European navy. It should have been an easy target for bombers, but this massive vessel could hide in plain sight.

Hitler's navy used a toxic artificial fog to conceal the ship when it was stationed in a Norwegian fjord. And, according to new research, this ephemeral smoke left a lasting mark on some of the living witnesses of World War II: the trees.

"The effects of one military engagement during World War II are still evident in the forests of Norway, 70 years later," said Claudia Hartl, a tree-ring researcher at the Johannes Gutenberg University in Mainz, Germany. [Images: Missing Nazi Diary Resurfaces]

Hartl, who presented her findings here during the annual meeting of the European Geosciences Union, didn't set out to study "war dendrochronology." Rather, she was taking core samples from pine trees around Kåfjord, near the northern edge of Scandinavia, to reconstruct a record of yearly temperatures for the past 2,000 years. (The trees can live for dozens or hundreds of years, and even older stumps can be found preserved in frigid lakes.)