Disclosure: Some links may be affiliate links. If you buy an item via links on our site, we may earn a commission. Learn more.
The world is a diverse place with oceans, deserts, plains, and of course, forests. Did you know that forests cover around a third of all habitable land on earth (around 4.06 billion hectares), and there are around four trillion trees currently on the planet; that’s about 400 per human being!
Forests are incredibly important and the majority of the terrestrial life on earth relies on them as a home. And there’s more than one type of forest; shall we go into the trees and explore?
What is a Forest?
Some people use the terms woodland and forest interchangeably, but these words are designed to refer to two different things. Even though both are in relation to groups of trees.
According to the FAO, a forest is an area of land that covers more than 0.5 hectares and has trees that are higher than 16.4 feet (5 meters) as well as at least 10% canopy cover.
That said, most forests have a canopy cover of at least 60%, which is one of the things that sets them apart from woods which are not usually as dense.
Why are Forests Important?
Forests are the primary type of habitable terrestrial land and as such, millions of people live and work in them. In fact, as much as 20% of the world’s population relies on forests to support their livelihoods. That’s around 1.6 billion individuals.
What’s more, there is such a vast array of life in forests that we aren’t fully aware of it all. According to the WWF, in one year alone, as many as 400 new species were discovered in the Amazon rainforest; and that’s just one location!
Haven for Biodiversity
There is more forest cover on the earth than any other kind of habitat so it goes without saying that there are a lot of creatures that call these areas home. In fact, nearly half of all the species on earth live in a forest location and this includes almost 80% of all land biodiversity.
The types of animals that live in forests are widely diverse, including big cats, wolves, insects, birds, reptiles, and many more. If that wasn’t enough, forests are home to thousands of types of plants that are certainly not limited to trees.
There are also microorganisms that we cannot see with the naked eye, but their survival is imperative to that of many other species. Without forests, we wouldn’t see anywhere near as much life on earth.
Absorb & Store Carbon
Trees and plants ‘breathe’ out oxygen and absorb carbon dioxide, which is the main gas that causes global warming. Since humans are creating more and more carbon, it’s a good job that we have as much forest land as we do because the trees can soak this up and even store it.
Studies have shown the effectiveness of species-rich forests when it comes to storing carbon. In some cases, these trees are able to store carbon dioxide for hundreds of years so the more forests we have, the less impact from global warming we will see.
Livelihood for Humans
At least 20% of the world’s population relies on forests for their very survival. Forests provide the basic needs of humans, which include food, fuel, and even water, as well as providing many people with jobs. For example, tourism brings in millions of forest visitors every year, and they need tour guides.
On top of this, while most of us are living in the digital era, there are still indigenous tribes that live, eat, and breathe the forest. It’s thought that there are 476 million people living as part of indigenous tribes and this is no small number.
Provided that forests are properly managed, they provide humans with a source of renewable energy and with conservation efforts firmly in place, it’s now easier than ever to find sustainable materials that have come from forests.
Floods could be a serious problem in forests, but thanks to the tree roots, they’re not as bad as they could be. This is because the tree roots help the soil to absorb more water, so the risk of flash floods is greatly diminished.
Provides Useful Medicines
Forests are like nature’s pharmacy, and they provide humans with access to a wealth of natural ingredients that can be used for their medicinal benefits. While there are plants all over the world that have health benefits, up to 70% of plants with anti-cancer properties can only be found in tropical forests.
And don’t fall into the trap of thinking that these ingredients are only used in new-age medicine. That notion couldn’t be further from the truth. In fact, western doctors are prescribing medications with as many as 7000 medical compounds that have been sourced from forests. For example, quinine is an alkaloid found in a Latin American tree that is used to treat malaria.
It’s not just medications themselves but also medical supplies. Did you know that the attire worn by medical professionals is also sourced from forests?
Helps to Regulate the Water Cycle
The water cycle is essentially the movement of water between the earth and the sky and this is helped by trees in the forest. Plants absorb water in their roots and then release it back into the air through their leaves via a process known as transpiration. These cycles coupled with others such as condensation and rainfall, make up the complete water cycle.
Forests are incredibly diverse places and there are many layers to them. In each layer, you’ll find various species of wildlife and plants.
The emergent layer refers to the very tops of the tallest trees in the forest. Their crowns can be seen popping out of the top of the main forest canopy. At this uppermost layer, animals include monkeys, birds, and butterflies.
The canopy is the top of the trees, called the crown. When all of the crowns meet, a dense layer of foliage is formed therefore creating a canopy over the rest of the forest. This is an important layer for photosynthesis as well as home to things like squirrels, flying foxes, birds, and reptiles.
Underneath the main canopy are many smaller trees that haven’t grown tall enough to form part of the canopy. However, if a gap ever forms, some trees will quickly grow to fill this. In the understory, we find animals like birds, snakes, and frogs.
The shrub layer rises around five to 6 feet (1.8 meters) from the forest floor and consists of smaller woody plants and shrubs. Here there are animals such as flies, deer, and bears.
The very base of the forest is the forest floor which is where you’ll find various species of fungi, worms, insects, and other decomposers. This layer is usually covered in things like twigs, fallen leaves, and other forest debris.
Types of Forests
Forests around the world are very different depending on the region they’re found in. There are three main types of forest; tropical, temperate, and boreal. Let’s look at each one in a little more detail.
1. Tropical Forests
Tropical forests are sometimes referred to as rainforests, and while this is one of the types, there are more. They’re typically found close to the equator and cover around 10% of the earth. However, they are home to almost half of all the life on the planet.
Distribution of Tropical Forests
Tropical forests are found in very specific locations; 23 degrees north or south of the Tropic of Cancer and Capricorn. This means that they’re always closer to the equator, where they form a lush green band around the center of the planet.
One of the most famous tropical forests is the Amazon which is located in Brazil but also spreads into Bolivia, Peru, Columbia, Ecuador, Guyana, and Suriname.
Some of the other tropical forests in the world are:
- The Southeast Asian rainforest
- The Congo rainforest
- The Daintree rainforest
- The New Guinea rainforest
General Characteristics of Tropical Forests
In order to be called a rainforest, a tropical forest must have at least 67 inches (1750 mm) of rainfall each year. Moreover, rainfall is consistent throughout the year and not unevenly distributed.
There is great biodiversity in tropical forests, and while we don’t know the exact number of species found in these forests globally, scientists estimate it to be between 3 and 50 million.
The climate in a tropical forest is much more consistent than in other places on the planet, with the temperatures not changing much throughout the seasons. Typically, it may be anywhere between 68 – 95 °F (20 – 35 °C) and very humid.
There is always direct sunlight on the tropical forest owing to its location. This allows plants to perform photosynthesis all year round. However, the forest is dominated by big trees with large leaves which cover the smaller plants growing lower down.
While tropical forests contain a lot of plant species, the soil here is surprisingly poor in nutrients. This is because the constant precipitation washes a lot of the goodness away. However, that doesn’t mean that the plants are missing out. The amount of decaying matter on the forest floor enriches the soil once again. That said, the plants quickly absorb these nutrients leaving very little in the soil.
Types of Tropical Forests
- Evergreen Rainforests – rainforests are wet and humid environments with around 79 inches (2 meters) of rain each year. They are often very dense and are the most diverse in terms of plant and animal species.
- Tropical Moist Forests – unlike evergreen rainforests, moist forests are made up of semi-evergreen deciduous species because of their location a little further from the equator, which means there is more definition between the seasons. It’s here that you’ll often see monsoons.
- Tropical Dry Forests – the trees in dry tropical forests are almost always deciduous, and they need to be because there’s very obvious seasonality here. For half of the year, it doesn’t rain at all, whereas the other half experiences a lot of rain. The plants and animals here have adaptations to help them survive extreme conditions.
- Cloud Forest – at higher elevations, we find cloud forests that feature shorter trees and whose canopy is in line with the clouds. These forests are often very misty and dark.
- Mangroves – a mangrove is found around coastal areas and is usually surrounded by brackish water. There isn’t much species diversity here and most of the trees are evergreen.
Threats to Tropical Forests
As many as half of the world’s tropical forests have already been destroyed and there are ongoing issues with things like deforestation. The good news is that, while there are a lot of threats to these forests, conservation efforts are well underway.
The act of cutting down large portions of forests is called deforestation, and while it is necessary in some cases, humans are overdoing it. Large areas of tropical forests are being removed to make way for agricultural land, and it’s thought that up to 58,000 sq mi (150,278 sq km) are being cut down annually.
While agriculture is one of the contributors to tropical deforestation, illegal logging is thought to be the main cause of concern.
Forests in South and Central America are under serious threat from deforestation but it’s those in West Africa that are facing the biggest problems due to the ever-growing population.
Tropical forests are home to millions of species, but many of these are under threat from poachers. For example, the Amazon manatee is poached so frequently that it almost disappeared from the wild entirely.
Climate change has played a serious role in the degradation of the Amazon rainforest. So much so that it’s thought that the area will eventually turn into a dry savannah because it won’t be able to generate its own rainfall and the ecosystem will fail. It’s thought that for every significant rise in temperature, there could be between a 10-20% decrease in annual rainfall in these forests.
2. Temperate Forests
Temperate forests make up around 25% of the world’s forest cover, although recent findings show this figure could be falling. While the biodiversity here isn’t quite as strong as that in tropical forests, these areas are still home to a plethora of animals, including birds, deer, chipmunks, kangaroos, rabbits, and wild boars, among others.
Distribution of Temperate Forests
You’ll find the temperate forests located at mid-latitudes and owing to this location, they have much clearer seasons.
These forests are widespread across Europe and North America as well as parts of Asia, including China, Russia, Japan, and Korea.
Some of the most famous examples of temperate forests include:
- The Appalachian temperate rainforest
- The Caspian Hyrcanian forest
- Taiheiyo evergreen forest
- Eastern Himalayan broadleaf forest
General Characteristics of Temperate Forests
The climate of temperate forests is typically described as moderate, and these areas will usually have four distinct seasons. However, the colder seasons do cover six months of the year, so the trees here tend to be slower growing.
The species diversity of trees in a temperate forest is nothing like that of a tropical forest, and there are typically only three to four species per square kilometer (approximately 1.2 to 1.6 species per square mile). However, there is much more diversity in the understory as the soil here is far more nutrient-rich. The most common tree species in these forests include things like oak, hickory, and maple.
The temperature in a temperate forest can vary greatly. In winter, it can get as cold as -22 °F (-30 °C), while the summer temperatures can easily exceed 85 °F (29 °C). Normally, these forests wouldn’t get more than around 59 inches (150 cm) of rain each year.
Types of Temperate Forests
- Deciduous Forest – these forests do not have a dense canopy which means the sunlight can easily reach the floor. The trees here, all deciduous species, lose their leaves in fall and become green again in spring.
- Coniferous Forest – trees in these forests don’t lose their leaves because the temperatures here are constantly colder. However, this does mean that trees in coniferous forests tend to grow more slowly.
- Mediterranean – these forests have very hot and dry summers, while the winters are much cooler and moist.
- Temperate Rainforest – unlike tropical rainforests, a temperate rainforest isn’t as warm. However, it still experiences heavy rainfall throughout the year.
Threats to Temperate Forests
Just like tropical forests, temperate forests face certain threats.
Many years ago, much of the earth was covered in temperate forest but so much of it has been cleared now in order to provide space for human settlement.
Sadly, temperate forests are also facing threats because of the number of endangered species living in them. These areas are some of the worst in the world for animal species that are under threat. In the US alone, temperate forests are home to as many as 12 endangered mammal species, such as the red wolf.
As with tropical forests, our temperate forests are facing threats as a result of climate change. The largest forest in North America, located in Alaska is currently facing significant changes due to global warming, where winter snow is rapidly turning to winter rain. As a result of this, the wildlife is suffering with serious impacts on the salmon population.
Studies have also shown that there is a decline in the number of species that depend on deadwood substrates, such as arthropods.
3. Boreal/Taiga Forests
Up to 31% of the forest cover on earth is made up of boreal forest, and it’s this type of forest that creates the largest terrestrial biome. You’ll sometimes hear these forests being called taiga, and they’re home to animals like wolves, bears, and moose. Interestingly, these forests were formed by glaciers many millions of years ago, and this has affected everything from the geology to the soil quality.
Distribution of Temperate Forests
Boreal forests are found across North America and Eurasia, in countries like Canada, as well as in Alaska and many areas of Scandinavia. However, as much as two-thirds of the world’s boreal forests can be found in Siberia. Note that these forests are found between 50 and 60 degrees latitude.
These forests are usually divided into three zones which include:
- The high boreal
- The mid boreal
- The southern boreal
General Characteristics of Temperate Forests
Boreal forests experience some of the coldest temperatures of all forest types, with winter sometimes getting to below -65 °F (-54 °C). There is a distinction between summer and winter, although the former is typically very short, with a growing season that usually only lasts for around 130 days.
The soil quality in boreal forests is among some of the worst, and the pH of the soil here is incredibly acidic. Owing to this and the fact that it gets so cold here, the diversity of trees is not very great. There are many coniferous trees like pine and spruce, although some deciduous species remain, including willow and poplar.
Boreal forests are among some of the most remote and vast on the planet. As a result of this, they are one of the most important carbon stores in the world.
Types of Boreal Forests
- Open Canopy Boreal – these forests are found in northerly locations and are usually colder. Because of this, there isn’t a great deal of species diversity.
- Closed Canopy Boreal – there is a very good species diversity in closed canopy boreal forests owing to the lower latitudinal location and therefore higher temperatures. Because of the rich soil in these areas, the trees tend to grow more densely.
Threats to Boreal Forests
Boreal forests are among some of the most beautiful places on earth, but they are sadly under threat from several things.
As with other types of forest, boreal forests have been cleared to make way for humans, and this is one of their greatest threats. The main issue here is not only for the forest itself but the range of animals that live here, such as wolves, moose, bears, and several species of carnivorous birds.
Some of the animals that live in boreal forests are under threat. Most notably, the caribou which is now at risk of extinction because of habitat loss as a result of deforestation.
One of the biggest threats to the boreal forests is climate change as these areas rely on colder weather. This is because of the layer of permafrost on the forest floor. When temperatures rise, it causes this to melt which makes the ground far too moist and even swampy in some parts. This means that trees are unable to survive, and many are dying off.
We might imagine wildfires taking place in very dry forests in places like Australia but they’re becoming increasingly common in boreal forest. However, it’s not the fires themselves that are posing a risk, but the carbon they create.
Yes, the fires are a result of climate change, but when they start, they emit significant amounts of carbon, which are then released into the atmosphere. Where boreal forests are excellent carbon stores, these wildfires are throwing out the balance.