Woods of Wonder

Woods of Wonder

Oh, That's Old! Old-growth forests look very different from one another. Some have only one kind of tree. Others have many kinds of trees. Some may have very tall trees. Others have trees that are short.

These forests are so different that scientists do not have one definition for old-growth forests. Yet many old-growth forests do have things in common. Many scientists think that an old- growth forest must be at least 150 years old. Not every tree in the forest has to be that old, though.

The canopy should have more than one layer. The tallest trees form the top layer. Fallen trees make holes in the canopy where sunlight gets through. Young trees can grow in these holes. Dead trees give food and shelter to many living things. Old-growth forests are home to plants and animals that can't live anywhere else. If we study and care for these forests, we can learn a lot.

United States California has many great national parks, some with old-growth forests. In Sequoia and Kings Canyon National Parks, coniferous trees make up most of the old- growth forests. Giant sequoias grow here, and one of these giants is the largest tree in the world. A sequoia can live for more than 3, 000 years.

The Pacific fisher also lives in the park. Its favorite meal is porcupine. Because it only lives in old-growth forests, some states are trying to protect it.