Gladys Calderon, age 9, of Portland, Ore., for her question:

WHY DO SOME TREES LOSE LEAVES?

A tree that loses its leaves at a certain time each year and later grows new leaves is called a "deciduous" tree. The trees lose their leaves because it is nature's normal way with this type of tree.

In the northern temperate region, most deciduous trees lose their leaves in the fall, stay bare all winter and then grow a new set of green leaves when spring arrives. Scientists say losing the leaves helps deciduous trees to conserve water.

Deciduous trees usually have broad leaves. Such trees include ash, beech, birch, chestnut, maple and some oaks.

Dried leaves continue to hang on the branches of some deciduous trees until the new leaves come out. In warmer climates, deciduous trees leaf out earlier and keep their leaves later in the season.