Something different takes place in each of the three rings at the same time.

VOA: special.2009.01.11

The rings were international in scope, connected to the city of Deal, New Jersey,Brooklyn,New York, Israel and Switzerland,"

VOA: standard.2009.07.24

"In the tropics, a lot of tree species don't even form rings that we can see.

VOA: standard.2010.04.05

Using samples from around Southeast Asia, Buckley and his colleagues saw this pattern in tree rings from recent years, when he could corroborate the rings with other historical climate information.

VOA: standard.2010.04.05