Tropical and Temperate Rainforests

A tropical forest is any forest located between the Tropic of Capricorn and the Tropic of Cancer or approximately withing 1400 miles of the equator. When one passes out of the tropics, one enters what are referred to as temperate zones and those extend up until the Polar zones are reached.

Defining a rainforest is a bit more difficult as there are several different definitions on the web. For our purposes, we will use the one supplied by Princeton, “rain forest: a forest with heavy annual rainfall” (wordnet.princeton.edu/perl/webwn) and will add that rainfall should be evenly spread throughout the year with high humidity. There are both tropical rainforests and temperate rainforests. What are the differences between the two?

One obvious difference is their location and temperature range. The tropical rainforests of the world are much better known and found through out South America (primarily the Amazon Basin), Central Africa (The Congo rainforest was immortalized in Conrad’s novel, Heart of Darkness) and through out Most of Southeast Asia and the islands of the South Pacific. There are also tropical rainforests in the Eastern Caribbean and in Australia/ New Zealand area. The rainforests of the tropics are extremely large and believed to contain close to 90% of the species of life living on land on the planet. Temperature in tropical rainforests is steady with little daily or seasonal variation. Tropical rainforests general have short lifespans for individual plants, lasting 50 to 100 years and most of the plants have broad shaped leaves.

There are a few temperate rainforests with the best known being on the Pacific Coast of North America. There are a few pockets also found in Asia. The diversity in these rainforest is still amazing compared to normal forest, but not as high as those in the tropics. The plant life is less and so are the things feeding on them. There are also no well know predators in temperate rainforest, whereas the tropics have large cats such jaguars, lions and tigers plus high numbers of reptiles.

Because temperatures and seasons are much more variable the further one gets from the equator, the organisms living in temperate rainforests have to be more flexible and able to adapt. Temperate rainforest plants can adjust to changes in light and have bigger root systems for storage of nutrients than topical rainforest plants. Conifers are found in temperate rainforests and individual plants may live for over 1000 years. The animals are also more adaptable.

Tropical rainforests are larger in land area and located close to the equator. Plants have shallow root, broad leaves and live generally less than 100 years. Temperate rainforests have fewer species with slower growing plants that are longer lived and they are found in temperate regions, greater than 1400 miles from the equator.