Tirpitz engagement recorded in trees
The relentless campaign to find and sink Germany's WWII battleship, the Tirpitz, has left its mark on the landscape that is evident even today. The largest vessel in Hitler's Kriegsmarine, it was stationed for much of the war along the Norwegian coast to deter an Allied invasion. The German navy would hide the ship in fjords and screen it with chemical fog. This "smoke" did enormous damage to the trees which is recorded in their growth rings. Claudia Hartl, from the Johannes Gutenberg University in Mainz, Germany, spoke with our science correspondent Jonathan Amos.