There are more than 40,000 kinds of trees in the world. All trees have the same parts. Roots pull up water from the soil. Leaves make food from the sun. Bark protects trees from harm. Branches and trunks support trees.


Circle of Life


Like all living things, trees have a life cycle. One kind of tree, an evergreen, has leaves shaped like green needles. Instead of fl owers, evergreens have cones. Male cones make pollen. Wind carries the pollen to female cones where seeds are produced. When the seeds fall to the ground,


they sprout and grow into seedlings. Seedlings grow into trees. T e trees make cones. T e cycle begins again.


Life After Death


When a tree dies, nothing is wasted. If it falls, it opens up space for sunlight. T e sunlight helps seeds sprout and take root in the ground. Some trees sprout on the trunks


of fallen trees. T ese fallen trees are called "nurse logs." T ey provide nourishment as they rot.


A nurse log helps bring new life to the forest.


12 NATIONAL GEOGRAPHIC EXPLORER


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