The weather was so temperate that he played outdoors all year long.

WSJ: A Cricket Paradise in Jersey

"There's no known source of caffeine in temperate zones, so there's nothing we can suggest as a sort of alternative hypothesis at this point except for a human source, " she said.

CNN: Researchers find caffeine in waters off Oregon

"Much of the world's population in North America, Europe, most of China and large portions of Russia live near temperate forests, so what happens in these forests has global importance, " said Jerry Franklin, a professor of forest resources at the University of Washington whose work was instrumental in maintaining the research plots.

CNN: Global warming threatens forests, study says

So far, its scientists have identified 600 genetic markers in ten species of eucalyptus, acacia and melaleuca, a temperate tree prized for its oils.

ECONOMIST: Trees are the next target of genetic engineers