In this lesson, you'll learn about three main types of forests found on earth: coniferous, deciduous and tropical rainforests. You'll also discover how the ecosystems where these trees are located affect the biodiversity within them.
On Earth, there are a few different types of forest. It doesn't matter what type you're referring to; when you say the word 'forest,' the first thing that typically springs to mind is trees. There are three main categories of forest: deciduous (also called temperate forests), coniferous and rainforests. Rainforests are typically found in the tropics, or lower latitudes. The areas where rainforests are found form a band around the middle of the earth near the equator. As you move outwards towards the North and South Poles, you start to run into deciduous forests in the temperate latitudes. Coniferous forests are only found in the Northern Hemisphere, close to the top of the earth.
One of the biggest differences between forests is in their names. Coniferous means 'cone bearing,' and these are trees that have cones, like pine trees. Most conifers are considered evergreens, because they never lose their leaves and are 'forever green,' regardless of the season.
Deciduous trees, on the other hand, lose their leaves each year. Deciduous means 'falling off.' This can happen for two reasons. Deciduous forests, which are mainly comprised of trees such as oaks and maple trees, are the trees that turn colors in the fall. These trees lose their leaves when cold weather comes.
Another interesting fact is that rainforests are a type of deciduous forest, despite the fact that they are considered to be evergreens. However, instead of the forest trees losing their leaves due to winter and cold temperature, these trees lose leaves when there isn't enough rain and they dry out. This rarely happens, because the rainforest receives so much precipitation over the year.
Differences in Forest Temperature
There are several key differences that distinguish these forest types from one another. The first is temperature. Deciduous and coniferous forests experience all four seasons: fall, winter, summer and spring. As these forests experience seasons, the ecosystem temperatures fluctuate between quite cold (about -15°F) and relatively warm (around 50°F). The specific temperatures depend on where the forests are found.
Coniferous forests, the forests found closest to the North Pole, experience some of the coldest temperatures and longest winters, with little rainfall. The deciduous forests have a milder winter, with more rain, typically between 30 and 60 inches a year. Rainforests, on the other hand, are typically hot and humid year round, as they are found right around the equator. These forests can receive up to 80 inches of rain a year. (That's almost 7 feet!)
Forest Biodiversity - Coniferous Forest
The biodiversity of these forests follows a simple pattern: As you move from the poles towards the equator (or from the coniferous forest to the rainforest), the biodiversity, or different animal and plant life, increases. So following this pattern, the coniferous forests, or the forests nearest the North Pole that experience the lowest temperatures and longest winters, have the lowest biodiversity. As stated earlier, coniferous forests are home to mostly evergreen trees, such as pines, spruce and firs.
These are the typical species we get for our Christmas trees. We also find large predators, such as bears, wolves and lynx. You might even find a tiger or two! Large herbivores, or animals that eat only plants, such as elk, are also found in these forests. The remaining biodiversity is made up of insects and squirrels.
Forest Biodiversity - Deciduous Forest
As trees in the deciduous forest lose their leaves, it allows for a greater biodiversity. Organisms and plants that were covered in the spring and summer months are now exposed, which can lead to greater predation as well as new plant growth. These forests support trees, such as oak, elm, maple and aspen trees. We also start to see more plant species in these forests, such as ferns and primrose. These plants provide food for animals, so a greater biodiversity of animals exists in these forests as well. The large predators in deciduous forests are generally smaller than in coniferous forests. We find black bears and coyotes as well as bobcats. The large herbivores are mostly comprised of deer.
We also start to see birds of prey in these forests, such as eagles and owls, as well as other bird species, like woodpeckers, blue jays and swallows. There are a number of smaller mammals in these forests, such as mice, squirrels, chipmunks and rabbits. There are also reptiles in deciduous forests, such as turtles and snakes. Interestingly, in some deciduous habitats, one of the most abundant animal types is slugs.
Forest Biodiversity - Tropical Rainforest
The tropical rainforest has, by far, one of the highest biodiversities found on the planet. There are thousands of species of plants and trees, and it is estimated that hundreds of species have not been discovered yet! Many plants from the rainforest are known to have medicinal properties. These have been cultivated for human use, in anything from heart medications to cancer treatments.
The biodiversity of the rainforest starts with insects, and there are a lot of them. Leaf-eating insects, butterflies and termites are all abundant in the rainforest. Unfortunately, so are mosquitoes! Amphibians include multiple species of frogs; the most well known is the poison dart frog. Indigenous tribes coat arrow tips in the poison this frog secretes. There are numerous species of snakes and lizards as well.
Bird-life includes species such as toucans and parrots. The mammal species in the rainforest are also quite vast. Top predators include big cats, such as jaguars. Large primates, such as orangutans and chimpanzees, along with numerous species of monkey and lemur, are found in rainforests. Other mammals include bats and sloths.
The three main types of forest found on Earth are coniferous, deciduous and rainforest. Coniferous forests are comprised of trees that bear cones, are located in the Northern Hemisphere close to the North Pole and have the lowest biodiversity of the three forest types. Both coniferous and deciduous forests experience all four seasons.
Deciduous forests, or forests made up of trees that lose their leaves, have higher biodiversity than coniferous forests. Rainforests are found along the equator, and have the highest biodiversity of any ecosystem found on the planet. They are also considered to be a type of deciduous forest, but instead of trees losing their leaves due to the cold weather of winter, they lose their leaves due to lack of rain.
After viewing this video lesson, you should be able to:
- Realize the equator is surrounded by the rainforests (deciduous types)
- Know that close to the equators are the deciduous forests (changing color, losing leaves)
- Remember that the coniferous forests are in the Northern Hemisphere only, close to the pole and bear cones