Kevin, Nadine, and Dad looked at the huge tree lying in their backyard.
"I can't believe the storm blew our tree down," said Nadine.
Tears filled her eyes.
"I loved climbing that tree," Kevin said sadly.
Dad sighed.
"This old oak tree was here when my dad built this house."
A truck pulled into the driveway.
Workers with chainsaws got out.
The workers cut off the small branches.
Then they cut into the thick trunk.
Sawdust filled the air.
With a giant crack, the trunk broke in half.
"It has rings of wood inside!" said Nadine.
"Most trees add one ring every year," said Dad.
"We can count the rings to find the tree's age."
Kevin and Nadine took turns counting.
"Our tree was 213 years old!" Nadine said.
"That's right, and it has a tale to tell," said a lady behind them.
"You must be Dr. Learner," said Dad.
She smiled at the kids.
"Dr. Learner is taking a slab for the Tree Ring Lab.
It's at the University of Arizona," said Dad.
Dr. Learner explained that the Tree Ring Lab had two million tree samples.
"Trees build a picture of the earth's history," she said.
She pointed to a thin ring in the trunk.
"This year had little rain, so your tree did not grow very much."
"Cool!" said Nadine, pointing to a thick ring.
"This year was rainy."
"Trees are like a weather calendar!" said Kevin.
"More than that," said Dr. Learner.
She pointed to a twisted ring.
"This scar shows that something unusual happened—likely a fire.
Trees can tell us about big events.
A tree would grow less if a hurricane blew off its leaves.
Or if a volcano erupted."
Kevin laughed.
"People would remember a volcano eruption!"
Dr. Learner showed them a picture of a tree slab.
It was twice as tall as a man.
"This tree grew from 212 to 1913."
"Whoa! That's 1,701 years!" said Nadine.
Kevin shrugged.
"Okay, maybe trees are better than people at remembering things."
Dr. Learner smiled.
"The oldest living tree is five thousand years old."
Nadine's eyes grew wide.
"How do you know that without cutting it down?"
"We use a tool that drills a tiny hole," said Dr. Learner.
"It doesn't hurt the tree."
The workers finished.
The backyard was quiet.
It looked strange without the tall tree.
Nadine spied something near the fence.
"Look! Our tree had a baby!"
The family hurried over.
The tree was tiny.
"I wonder what stories this tree will tell in the future," said Kevin.
"I don't think you'll find out," said Dad.
"But maybe your grandchildren or your great-grandchildren will."