They're the biggest and oldest living things on the Earth,Judy.
Judy
Yes,but what good are trees.They make streets more beautiful and less noisy,but what else can they do?
DR RAY
Well,the wood in your pencil,the rubber on the end of your pencil,the paper in your notebook and the fruit in your bowl all come from trees.And,I suppose you also enjoy breathing pure,cool air.
Judy
Of course.
DR RAY
Then you must thank trees for that too.They take harmful gases from the air,and release oxygen back into the air.How many people are there in your class,Judy?
JUDY
Forty-six.
DR RAY
Well,one and a half hectares of trees could produce enough oxygen to keep your whole class alive and healthy for a whole year.
JUDY
That's wonderful!
DR RAY
Trees cool the air as well as clean it.They are natural air conditioners.Three trees can do the job of 15 air conditioners running almost all day.
JUDY
You certainly know a lot about trees,Doctor Ray.
DR RAY
Thank you,Judy,but I don't,really.Scientists are only now beginning to understand them.For example,when insects attack a tree,it can warn its neighbours.The trees can then protect themselves by producing a chemical that makes their leaves taste nasty.And some trees can join their roots together underground,and pass food and water to each other.Trees are communicating with one another,but we don't know how.
JUDY
Are trees in danger?
DR RAY
In great danger.We cut down and burn millions every year,but we replace hardly any of them.We are destroying our best fighters against pollution.
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