JOAN CARTAN-HANSEN, HOST: Forests play an essential role in our world.

They provide a home, food for thousands of creatures, fuel, and recreation for people, and much more.

Let's find out more about forests.

(MUSIC) AUTUMN: Forests cover about 30 percent of the earth's surface.

JOAN CARTAN-HANSEN, HOST: That right.

Forests are one of our world's biomes.

A biome is a large geographical area that contains similar plants, animals and environments.

A forest is a complex community of life in which trees are the dominant life form.

LILY: There are three basic types of forests.

The tropical rainforests, temperate forests, and boreal forests.

CORBIN: The type of forest can be defined by the type of trees and the amount of rain.

CARTAN-HANSEN: Rain forests are mostly found around the equator.

They cover about seven percent of the earth's surface.

Rain forests have the greatest variety of trees.

They have two basic seasons, wet and dry.

And because the climate is so warm, rain forests are evergreen, that is the trees don't lose their leaves.

Rain forests are so moist that some can even create their own rain.

AUTUMN: Temperate forests grow in North America, northeastern Asia, western and central Europe and south of the Equator.

Temperate forests enjoy all four seasons of weather.

CARTAN-HANSEN: Temperate forests have deciduous and conifer or evergreen trees.

LILY: Deciduous is Latin and it means to fall.

Deciduous trees lose their leaves in the fall and re-grow them in the spring.

CORBIN: Conifer or evergreen trees have needles and keep them year-round.

CARTAN-HANSEN: Temperate deciduous forests in North America have trees like oak, maple, and beech.

In the Southern hemisphere, tropical deciduous forests have a warmer climate.

Trees here don't grow as tall.

Their trunks and branches twist more, and their trees' bark is thicker.

Forests, no matter the type, have three basic zones.

The top is called the canopy.

That's where branches join together to form sort of a roof over the rest of the forest.

The next level is the understory.

That the area where small bushes, plants and saplings live underneath the mature trees' canopy.

The final level is the forest floor.

Here living things like algae, fungi, lichen, moss and the decaying plants and leaves create a squishy carpet on the forest floor.

CORBIN: Here's a fact for you.Insects are the only creatures that live at all levels of the forest.

CARTAN-HANSEN: More than five million land species depend upon forests for their survival.

Forests are where they live, where they find food.

Forests provide services to people too.

They absorb carbon from the atmosphere.

They give us wood for fuel, furniture, houses, and paper.

They give us a place to recreate and enjoy nature.

Forests and the plants that live in them are the basis for medicine and food.

Forests give us the ability to regulate temperature and they clean the air of pollution.

Most importantly, forests clean our water and provide oxygen we breathe.

LILY: One large tree can capture and filter 36,500 gallons of water a year.

AUTUMN: And two mature trees provide enough oxygen for one person to breathe over a year.

CARTAN-HANSEN: Forests are so important; they've been called our planet's lungs.

But the world's forests are in trouble.

More than fifty percent of the planet's forest have already been destroyed.

And we are losing forests at a staggering rate.

The equivalent of the size of 48 football fields every minute.

Some forests are cleared for agricultural uses or mining.

Some are lost to disease and pests.

Large amounts are lost to wildfires.

LILY: We need to take care of our forests.

We need our forests for clean air and clean water.

CORBIN: We need forests for recreation and for a home for all those animals and plants.

AUTUMN: So, you do your part so we all have forests to enjoy.

CARTAN-HANSEN: If you want to learn more about forests, check out the Science Trek website.

You'll find it at ScienceTrek.org.

(MUSIC) Science Trek on Idaho Public Television is made possible through the generous support of the Laura Moore Cunningham Foundation, committed to fulfilling the Moore and Bettis family legacy of building the great state of Idaho.

By the Idaho National Laboratory, mentoring talent and finding solutions for energy and security challenges, by The Friends of Idaho Public Television and by the Corporation for Public Broadcasting.