We’ve heard about “saving the rainforests” for years, but why are they so important? Here are some facts about some of nature’s most amazing phenomena.
The Facts: Rainforests—forests with an average year-round temperature of 70°F and annual rainfall of more than 60 inches—are home to 50% of life on Earth…even though they make up only 6% of the landmass.
• More types of woody plant species grow on the slopes of a single forested volcano in the Philippines than grow in the entire United States from coast to coast. Forests in the tiny country of Panama contain as many plant species as all of Europe.
• More species of fish live in the Amazon River than in the entire Atlantic Ocean. One study found more species of ants living on a single tropical stump than are found in all of the British Isles.
• Yet scientists estimate that they have discovered and identified only one-sixth of the species living in rainforests.
The Facts: The ecosystem of a rainforest is upside down compared to other forests: nutrients are stored not in the soil, but in the canopy of plants above it.
• In forests with temperate climates, the deciduous trees all drop their leaves at roughly the same time, triggered by the change of seasons. Dead leaves gradually decompose and turn into rich soil.
• That doesn’t happen in the rainforest—there is no change of season; tropical trees drop their leaves gradually over the entire year.
• The constant heat and moisture of the climate spur the continuous growth of bacteria, insects, and fungi, which feed on the dead leaves—causing the forest floor to act as a huge living stomach.
• Result: Decomposition (which can take one to seven years in a temperate forest) takes only six weeks in a rainforest. Downside: The rich loamy soil that accumulates in temperate forests never gets a chance to build up on a rainforest’s floor.
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The Facts: The forest canopy protects the ground. Some areas of the Amazon receive up to 400 inches of rain annually. But without leaves and branches to shield the ground from pounding rain, water would run off immediately, taking any topsoil with it.
• Millions of years of daily rainfall combined with constant heat have drained nutrients from rainforests’ subsoil, leaving it high in toxic aluminum and iron oxides. This makes it unable to support much plant life.
• If exposed to the sun, the ground would become unproductive, hard-packed, and cement-like. The small amounts of nutrients left in the soil would be quickly leached away.
• The balance is fragile. It’s estimated that the Amazon produces 20% of all the oxygen generated by land plants on Earth. Without the climate moderation of the forest, the greenhouse effect—rising temperatures and plummeting rainfall—may be greatly accelerated.
The Facts: Over half of the world’s rainforests are gone forever—most have disappeared since 1960.
• Loggers, ranchers, miners, and farmers cut or burn the Amazon jungle down at the rate of 40 to 50 million acres annually.
• A 2.5-acre tract of healthy, growing rainforest loses about three pounds of soil through erosion annually. Cut the trees, and the same forest can lose up to 34 tons in a year.
• As settlers clear the forest to make room for agriculture or livestock, they discover the land supports them for only a few years.
• Once the forest is cleared, the only nutrients left are in the ashes. When the soil disappears, the rainfall diminishes, and the forest is gone for good. The damage is irreversible.
• Today, an area the size of the state of Washington is bulldozed every year. At that rate, it will take less than 50 years to destroy the remaining jungle. Some ecologists estimate that the Amazon will be completely gone by the year 2040.
• Scientists fear species are becoming extinct before they are even discovered—a scary prospect since roughly 25% of all prescription drugs contain ingredients originating in the rainforest.
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The Facts: The Amazon contains half the world’s tropical forests, spread over an area the size of the continental United States.
• While North American forests rarely have more than 15 species of trees in their entire ecosystem, the Amazon can contain between 100 and 250 different species in a five-acre plot. You can sometimes travel a mile or more before finding two trees of the same species in the Amazon.
• More than 100 types of plants and 1,700 kinds of insects can be found in the branches of a single mature tropical tree.
• The Amazon has more than a million interdependent—and exotic—species of plant and animal life. A few examples:
trees with 6-foot-long leaves |
slugs the size of small snakes |
flowers with 3-foot-long petals |
butterflies the size of dinner plates |
plants that can cradle 10 gallons of water in reservoirs formed by their leaves |
bees the size of birds tarantulas so big they eat birds |
rodents that weigh up to 100 lbs. |
catfish so big they’ve been known to eat children |
Why is the Amazon so diverse?
Thirty million years ago, the area that is now the Amazon jungle entered a dry period lasting thousands of years. The drought wiped out most of the region’s tropical forests—only isolated pockets of jungle survived. Over time, each jungle followed its own evolutionary course.
Then, following the last ice age (10,000 years ago), the climate became warm and wet again, and the different types of jungle grew together, each contributing many different plant and animal species.
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