Above and Below Olson’s glider helps him study leaves. He can see how leaves grow to capture sunlight. A tree with large leaves has its


leaves spread far apart. T e extra space lets in more sunlight. A tree with small leaves grows its leaves closer together. Some leaves grow in a spiral


around their stems. Others grow across from one another. Many have notched or cutout edges. Light can shine around the cutout parts to reach the leaves below. Olson knows all the diff erent


patterns leaves make. He knows that each pattern helps a tree get as much sunlight as possible.


Keeping Its Leaves


A conifer tree is diff erent from a deciduous tree. It doesn’t lose leaves in winter. Its leaves look like needles, but they act like other leaves. They use photosynthesis to feed the tree.


Life and Death Many tree leaves make food during spring and summer. T en comes autumn. T e days grow shorter. It gets cooler. In the fall, deciduous trees


begin to change. T ese trees lose their leaves in winter. First, photosynthesis slows down. T e strong green of the chlorophyll fades. Now other leaf colors like red, orange, and yellow appear. Finally, the leaves die. In the spring, new leaves will grow.


Into the Air T e next day, Olson goes to an open field. He straps himself into his glider. Soon, he is flying high above the trees. He studies the leaves in the


morning light. T ey are just beginning their day of hard work.


Wordwise


chlorophyll: a chemical in leaves that catches the sun’s energy


conifer: a tree that stays green year-round


deciduous tree: a tree that sheds its leaves at the end of a season


photosynthesis: the process by which organisms use sunlight to make food


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