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Forests cover one-fifth of the Earth's
surface and supply the world with some of life's essential
ingredients, such as oxygen and water. Trees provide habitats
for countless birds, insects, animals and plants. They supply
wood for building and making paper, as well as rubber and
many other products we use daily. Trees are also becoming
a source of new medicines as scientists study indigenous and
natural remedies for diseases such as cancer.
There are three major types of forests: tropical rainforests,
temperate forests and coniferous forests.
Tropical Rainforest
These forests typically grow where it is hot and humid most
of the year. Almost half of the world's forests are rainforests,
covering 16 percent of the Earth's land surface. They are
located in parts of Central and South America, Central and
West Africa, and Southeast Asia.
Rainforests are wetter than most forests because they are
located where there are heavy rains. They are also much denser
than other forests, and each rainforest is home to several
thousand different trees. The trees have very broad leaves
that are green all year long. Rainforests are very fragile
ecosystems, where a variety of plant and animal species survive
inter-dependently.
Temperate Forests
These forests, also known as deciduous, once covered most
of Europe and the eastern half of North America. Temperate
forests are found where there is a cold winter that interrupts
the growing season, less rainfall and cooler temperatures.
The forests may contain "hardwood" tree species such as beech,
oak, hickory and birch.
Many of the temperate forests were cut down in the early 18th
and 19th centuries to make way for industry and agriculture.
Trees in this type of forest shed their leaves once a year.
In subtropical areas, these forests remain green throughout
the year.
Coniferous
Forests
This third type of forest grows in areas where the winter
season is long and the growing season is short. Coniferous
trees, or cone-bearing trees such as pine and fir, are especially
suited for these harsh conditions. They have small needle-shaped
leaves that stay green during the whole year, and they have
tough seeds. While a coniferous forest may be large, it does
not have many different species of trees.
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