| Abundant sunlight, water, and warm temperatures encourage many different
kinds of trees to grow in a rain forest. Trees are tall (150 to 200 feet,
31 to 46 meters) and straight and grow close together, forming an unbroken
canopy overhead. A few very tall trees emerge from the canopy. The smooth
tree trunks have no lower branches; most of their leaves and flowers grow
near the top in the sunlight. The tree roots are shallow as they do not
have to go deep to reach water or nutrients. The trunks of the trees are
buttressed for support in the absence of deep roots, and garlands of vines
and air plants cling to the trees. The trees are broadleaf (the leaves
are broad, flat, and thin) and evergreen, as there is relatively little
change in the seasons. Many of the leaves have pointed tips to shed water.
Due to the lack of light, only a few short trees (25 to 50 feet high, 7.5
to 15 meters) grow below in the shade of the canopy.
It is always semi-dark on the floor of a rain forest. Unlike the
familiar jungle of the movies, there is little or no underbrush, except
in areas where sunlight can reach, such as along a river or in a clearing
created by a fallen tree. Few green plants grow in the gloom of the forest
floor. Fungi, which do not need sunlight, grow well here, and quickly decompose
fallen leaves. Much of the animal activity occurs high in the treetops. |
