When radiocarbon dating a piece of wood or charcoal, the event dated is the growth of the tree ring. Trees grow by the addition of rings, and these rings stop exchanging carbon with the biosphere once they are laid down.

Why is carbon used to date trees?

Over time, carbon-14 decays in predictable ways. And with the help of radiocarbon dating, researchers can use that decay as a kind of clock that allows them to peer into the past and determine absolute dates for everything from wood to food, pollen, poop, and even dead animals and humans.

How is wood carbon dated?

Radiocarbon Dating Because wood can be dated directly and by radiocarbon, scientists used bristlecone pines to calculate a new calibration curve, and convert radiocarbon results into accurate calendar dates.

Can plants be carbon dated?

Carbon-14 dating can be used to determine the age of everything from bones and plant fibers, to wood and pollen.

What is the oldest thing on earth?

Microscopic grains of dead stars are the oldest known material on the planet — older than the moon, Earth and the solar system itself.