Look over your head. What do you think is holding up that roof? Timber from trees, of course.

Now look out the window. Are there any birds? Where do you think they go to sleep at night? In the trees, of course.

Do you know any carpenters, or maybe foresters? How do you think they get paid? By working with trees, of course.

There are 25 tree species to be found in Ireland

You probably know all these things already, but maybe I could tell you some things you don’t already know.

Trees can suck pollution out of the air. They can prevent flooding. They can make humans feel happy, just by being around us.

They can even talk to each other. A German scientist called Peter Wohlleban found that trees that are getting nibbled on by insects can tell the other trees deeper in the forest what’s happening, and the other trees can make their leaves taste bad so the insects don’t attack them.

In Ireland, we have 25 species of trees. Much fewer than over in mainland Europe. That’s because after the last Ice Age when trees were finding new places to live, they found it hard to cross the seas between us and France.

Some seeds managed to get here, carried by the wind or in the tummies of birds.

Although we have a small number, the ones we have are really cool – the ancient oak, the magical hawthorn or the rare old elm tree, to name just a few.

The ash tree is one of my favourites, probably because it’s the tree we make hurleys out of.

When the great warrior Cú Chulainn was a boy, he got himself in a bit of trouble with his hurley by accidentally pucking his sliotar into a dog’s mouth. The dogs owner was not happy and Cú Chulainn spent a long time making up for his mistake.

Our ancestors loved trees. They named many towns and villages after trees.

If you cut down a tree without permission back then, you would be in big trouble with the king. In fact, we liked trees so much we made an alphabet based on them. You should look it up. It’s called Ogham.

In Ireland, we have 25 species of tree, much fewer than in mainland Europe. That’s because after the last Ice Age when trees were finding new places to live, they found it hard to cross the seas between us and France.

Back in those days, we had so many trees that a squirrel could travel for miles and miles without touching the ground. We cut most of them down to make space for cows and sheep and houses. That made sense at the time, but we now know, because of science, that we must put some of them back.

It’s going to be a big job.

Maybe you could help plant a few?

Ray Ó Foghlú is a conservationist and an educator. He works for An Taisce’s LEAF programme and for the charity Hometree.