Trees can help predict famines and wars

Long memory: Methuselah is a 4,850-year-old pine in California.

Scientists are finding that tree ring patterns are a time-map of rainfall and drought, accurately going back thousands of years. These might help us predict future famine and conflict.

What’s happening

Have you ever counted the rings inside a fallen tree trunk? Each ring is a single year in the tree’s life.

Some trees live to be hundreds or thousands of years old. Now, scientists have learned to use their rings to discover amazing things about the Earth’s climate in past centuries.

Find out more

How do they do this?

The light part of a tree ring grows during the spring and early summer. The dark part grows during the late summer and autumn. The light and dark rings together make one year.

The rings are larger when the weather is warm and wet. In a drought, the trees hardly grow at all.

By measuring the size of these rings, scientists can find out about the weather hundreds of years ago, long before people kept records.

And by understanding the effects of this weather they can learn to predict wars, famines and other big changes. Is this a good idea?

Some say…

Yes! Telling the future is all about understanding cause and effect. If we know that a drought is likely in the next ten years we can prevent a lot of suffering.

Others think…

Nature is too complicated for this. It is hard enough to get the weather forecast right. Tree rings might show us patterns for the past but they might not be repeated in the future!

You Decide

  1. What is your favourite tree?


  1. Find a tree and write a profile about it. What kind of tree is it? Does is it grow any fruit? How old do you think it is?

Some People Say...

“A tree’s wood is also its memoir.”

Hope Jahren

What do you think?

Word Watch

The Earth’s weather and temperature over a long period of time.
The atmosphere at a particular place and time, including its temperature, rain and wind.
Historical account or biography written from personal knowledge of the subject.


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