Oak Tree

The oak tree is a large, sturdy tree found across much of North America, Europe, and Asia. Oaks belong to a group of plants called the genus Quercus. There are about 500 different species of oak in the world. Some are tall trees that grow over 100 feet high. Others are short, bushy plants that stay close to the ground.

You can spot an oak by its leaves and its seeds. Oak leaves usually have rounded or pointed lobes along the edges, giving them a wavy shape. The seed of an oak tree is called an acorn. Each acorn sits in a small cup made of overlapping scales. Acorns are the only seeds in the world that look like this, so an acorn on the ground is a sure sign that an oak is nearby.

Oaks grow slowly, but they live for a very long time. A healthy oak can live 200 to 300 years. Some live much longer. The Pechanga Great Oak in California is thought to be more than 2,000 years old, older than the city of Rome. As an oak ages, its trunk grows thick and its branches spread wide. A big oak can shade an area as large as a basketball court.

Acorns are an important food for forest animals. Squirrels, deer, blue jays, woodpeckers, mice, and bears all eat them. Squirrels and jays bury acorns to save for winter, then forget where many of them are. Those forgotten acorns sometimes sprout into new oak trees. In a real way, squirrels and jays plant most of the world's oak forests.

Oak wood is one of the strongest woods in the world. People have used it for thousands of years to build ships, houses, barrels, and furniture. Many old wooden warships, including the famous USS Constitution, were built from oak. Wine and whiskey are still aged in oak barrels today, because the wood gives the drink its flavor.

Oaks have also been important in human stories and symbols. Ancient Greeks believed the oak was sacred to Zeus, the king of the gods. The Druids of ancient Britain held religious meetings in oak groves. The oak is the national tree of the United States, England, Germany, and several other countries. It often stands for strength and a long life.

Oaks face new dangers today. A disease called sudden oak death has killed millions of oaks in California. Warmer weather and new insect pests are also harming oak forests. Scientists are working to protect these trees, because losing oaks would mean losing food and shelter for hundreds of other species.