Forests cover approximately one-third of the earth’s land surface and are home to 80 percent of the world’s terrestrial species of plants, insects, and animals. There are three major forest zones, although each of these zones includes specific forest subtypes. The three major zones are tropical, temperate, and boreal.
Tropical forests are located close to the equator, between the Tropic of Cancer and the Tropic of Capricorn. They are spread mainly through Southeast Asia, South America, and Africa. Although tropical forests only cover a small amount of Earth’s land, they house almost half of all terrestrial species.
The plant life in the Amazon alone is thought to provide 20 percent of Earth’s oxygen. Because of the close proximity to the equator, temperatures are consistent and warm all year long. Many tropical forests have a rainy season and a dry season, yet they still receive an average of 80 inches of rainfall a year.
The balmy temperatures, high levels of rainfall, and consistent sunlight create an environment where many different plants, animals, and insects can thrive. Many of the species found in tropical forests are endemic to the particular area they live in.
The unique species of plants that are found in tropical rainforests account for approximately 25 percent of all natural medicine. This only includes the ones that have already been discovered; there are likely thousands more medicinal plants that have yet to be studied.
Monkeys, sloths, lemurs, and other animals that have adapted to life in trees thrive in the tropical forest. Tigers, elephants, and anacondas can also be found. Many different species of trees, ferns, mosses, orchids, and palms also all thrive in the hot, wet climate.
Although there is such a rich diversity of life in tropical forests, the soil isn’t very nutrient rich. Due to the high levels of rainfall, many of the potential nutrients are quickly washed away. Additionally, organic matter is swept away before it has the chance to properly decompose and release nutrients into the soil. The thin layer of topsoil contains the majority of the nutrients, which are quickly absorbed by the surrounding plants. 1
Subtypes of Tropical Forests
While most think of the tropical rainforest when imagining tropical forests, there are actually a handful of different subtypes within this category.
- Evergreen: Tropical evergreen forests receive rainfall year-round with no dry season.
- Seasonally dry: The seasonally dry tropical forests have alternating wet and dry seasons.
- Montane: Also referred to as cloud forests, these mountainous regions receive most of their precipitation from fog and mist.
- Tropical coniferous: Found mostly in Central America, these forests have low levels of precipitation and conifers adapted to life in warm temperatures.
- Subtropical: Located to the north and south of true tropical forests, these forests consist of trees that are adapted to resist summer drought.
- Swamp: Swamp forests are also referred to as flooded forests and are inundated with freshwater either seasonally or year-round.
- Dry: These forests are located at tropical and subtropical latitude but have long dry periods throughout the year. 2
Temperate forests are located between 25 and 50-degree latitudes in both hemispheres. There are four types of temperate forests: deciduous, coniferous, mixed, and rainforest. This type of forest is known for having four distinct seasons due to its location within a "temperate" climate.
Temperate forests are spread widely throughout North America, Eurasia, and small parts of the Southern Hemisphere. Temperate deciduous forests are found mostly in the eastern United States, Europe, western Russia, Canada, Japan, and China. Although temperate forests experience all four seasons, they tend to have fairly long growing seasons and a decent amount of precipitation spread throughout the year.
While temperate coniferous forests stay green year-round, trees in temperate deciduous forests lose their leaves in the fall. Temperate forests have very rich soil and support a wide variety of trees. Oaks, birches, elms, and maples are often found in deciduous forests, while pines, firs, and hemlocks can be found in coniferous forests. A variety of mosses, ferns, and shrubs can all be found in the understory.
Wildlife in these regions is either acclimated to life in harsh climates or migrates somewhere else for the winter. Temperate forests support a wide variety of wildlife, including bears, foxes, wolves, deer, squirrels, and rabbits. Koalas, wombats, and possums call the temperate forests of Australia home, while red pandas thrive in China’s temperate forests. Many migratory birds call temperate forests their home throughout spring and summer, living off of the abundance of seeds, berries, and insects.
Subtypes of Temperate Forests
- Deciduous: Deciduous forests are dominated by deciduous trees that lose their leaves with the coming of winter and regrow in the spring.
- Coniferous: Coniferous forests are dominated by cone-bearing needle-leaved evergreens.
- Mixed: A temperate forest which includes both deciduous and evergreen trees.
- Rainforest: Two-thirds of temperate rainforests are located in North America’s Pacific Northwest. This type of forest receives more rainfall and has milder temperatures year-round. 3
Boreal forests are also referred to as snow forests or taiga and are only found in far northern latitudes. There are no boreal forests in the southern hemisphere. The climate is very harsh and cold, which makes it difficult to support a vast range of plants and wildlife.
The average annual temperature of the boreal forest is between 23 to 41 degrees Fahrenheit. Instead of having four distinct seasons, the boreal forest only has a long, cold winter, and a short, moist summer.
The boreal forest is one of the largest biomes, comprising approximately one-third of the earth’s forests. These forests are typically located between 50 and 60 degrees N and stretch through Canada, Alaska, Russia, and Scandinavia.
Because the climate is so harsh, there are only 50 to 100 frost-free days a year. Boreal forests also only receive 12 to 33 inches of precipitation a year, mostly in the form of snow. Even so, low evaporation rates combined with low temperatures allow the ground to remain moist throughout the growing season.
The taiga is not home to as many plant and animal species as the tropical or temperate biomes. The soil in boreal forests is known for being very poor in nutrients and highly acidic. As needles fall from the coniferous trees, they continue to make the soil even more acidic, making it too toxic for other types of plants to grow.
Evergreen conifers that are able to withstand harsh temperatures thrive here, including pine, fir, hemlock, and spruce. Animals who call the taiga home often have thick coats of fur, and include moose, bears, elk, wolf, deer, and lynx. 4
Forests are an important source of Earth’s oxygen, and the rainforest is even referred to as the “lungs of the earth." Aside from converting carbon dioxide into oxygen through photosynthesis, trees also produce thousands of different beneficial terpenes that provide a wide range of therapeutic benefits, both physical and emotional.
Simply taking a walk through a forest, whether deciduous, rainforest, or coniferous, can ease your mind and soothe your soul. Just a 20-minute stroll through a wooded area has been shown to reduce cortisol levels, decrease blood pressure, and reduce feelings of stress and anxiety.
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