5. What Is A Rainforest?
Rainforests are regions that are wet throughout the year either due to rainfall in the tropics or due to a combination of rainfall and coastal fog in the temperate regions. Temperature rainforests experience defined seasons while the tropical rainforests occurring near the equator experience no defined seasons. The trees in both forests have a broad base to provide additional support for the heights they reach. Together these two types of forests support 50% of flora and fauna in the world.
4. Temperate Rainforests
Temperate rainforests are found in regions with heavy rainfall similar to tropical rainforests but have cooler temperatures than the latter. Average annual rainfall is between 80-135 inches (200-350 cm), and average temperatures are always above zero, around 39-540 F (4-120C). The rainfall is not evenly distributed throughout the year, and there can be dry periods, when fog from the sea supports the forest, so most temperate rainforests are found along coasts. Both broadleaved and coniferous trees are found in these forests.
Temperate rainforests are distributed all over the world, and the major forests are the Pacific (US and Canada, Appalachian (eastern US), Magellanic and Valdivian (South America), Knysna-Amatole (South Africa, Atlantic Oakland (UK), Colchis (Turkey and Georgia), Fragas do Eume (Spain, High elevation mountain (Taiwan, Baekdu and South Seas (Korea), Taiheiyo (Japan, Caspian Hyrcanian (Iran, Australian and New Zealand forests. According to the Worldwide Fund, the Pacific forests account for a quarter of the total area of temperate rainforests.
3. Tropical Rainforests
Tropical rainforests are very warm, and humid throughout the year due to the even rainfall that they receive. Annual rainfall in these forests is around 60 to 400 inches (152 to 1000 cm), and the average humidity is between 77-88%. Found near the equator, these forests are always warm, with 12 hours of sunlight around the year, and temperatures ranging between 68-93 0 F (20-340C).
The largest tropical rainforest is the Amazon Basin in South America. Other regions with tropical rainforests are the Caribbean Islands and Mexico (Central America), Congo Basin and Madagascar (Africa), and Southeast Asia, India, and some islands in South Pacific.
2. Habitats, Biodiversity, and Significance to Humans
In terms of biodiversity, the tropical rainforests are the richest among the terrestrial ecosystems, supporting 15 million species of plants and animals. They have many hundreds of tree species, while temperate rainforests have only up to 20 tree species. The temperate rainforests have less biodiversity compared to the tropical ones due to cooler temperatures.
Due to the same reason, nutrient cycling occurs faster in tropical compared to temperate rainforests. However, the trees in temperate rainforests grow taller than in tropical forests, and have more biomass, making them the most productive forests in the world. While the average height of trees is 80-115 feet (25-35 meters) in tropical forests, in temperature rainforests they can be as tall as 300 feet (90 meters). Trees live longer in temperate rainforests up to 500-1000 years, while they live only 50-100 years in tropical rainforests.
The rainforests are important for carbon sequestration storing 250 billion tons of carbon, maintain rainfall patterns, and protect the soil. The tropical rainforests are the source of one-fourth of the medicines humans use. Rainforests also provide livelihoods for many local communities.
1. Environmental Threats, and Conservation Efforts
Temperate rainforests are logged for timber given the impressive size of trees; 99% of the temperature rainforests in the US, including redwoods, have been logged. Other reasons for forest destruction are the conversion of land for agriculture and increasing urban sprawl, and acid rain due to pollution. The biggest threat to tropical rainforests has been and still is the conversion of land for agriculture and livestock farming. Mining for minerals, extraction of energy and timber, conversion to palm and pulp plantations, and road constructions are some other major reasons of tropical rainforest destruction. Two-thirds of the tropical rainforests exist as fragmented patches.
While large and small non-profits, governments and individuals are working with local communities to reduce extraction pressure on tropical forests, none of the larger industrial causes have been removed. Similarly, in the temperate rainforests commercial logging can be stopped only through government intervention. Converting to renewable energy, recycling, and reusing resources, going paperless are a few initiatives that individuals have been following, besides using consumer power to influence corporations and government to save the rainforests.