Only a handful of tree-ring calendars of that length exist, including the Huon pines of Tasmania and the venerable bristlecone pines of the American Southwest.

"This is the 'Holy Cow' range," said Jim Speer, a dendrochronologist who uses tree rings to reconstruct fire history at Indiana State University.

Boswijk has begun using her record to date 19th-century wooden buildings from the time Europeans reached the North Island. In the U.S., researchers used similar calendars to determine the age of the Pueblo Bonito ruins of New Mexico and the Kentucky log cabin Abraham Lincoln was born in.

But the rings also tell another story. Like pages in the Earth's diary, they chronicle the weather patterns of each year. Some