There are different areas all over the world, each of which is characterized by different vegetation. Vegetation is the totality of all plant species and communities that can grow in a given area. They form so-called vegetation zones.
vegetation zone definition
A certain area on earth is referred to as a vegetation zone, in which only certain types of plants occur. Vegetation zones are significantly influenced by the climate prevailing there.
climate and vegetation zones
Which plants live in the vegetation zones is influenced by the climate. These include above all the ones given there temperatures and the rainfall. The plants have corresponding strategies on how best to deal with the climatic conditions.
For example, a plant that needs a lot of water cannot live in areas where there is little rain.
The zones run parallel to the latitudes. It is warmest at the equator and the further away from the equator, the colder it gets. It is therefore very cold at the North and South Poles.
vegetation zones of the earth
The vegetation zones can be divided into eight different areas. Since the earth can also be divided into four climate zones and the vegetation zones are influenced by the climate, the respective vegetation zones can also be assigned to the climate zones at the same time. You now get an overview of all vegetation zones on earth and the climate zones in which they occur.
If you would like to learn more about the climate zones, please read the separate article!
Figure 1: Earth’s climate zonesSource: pixabay.com
The figure shows you into which climate zones the earth can be divided. Now you get shown which vegetation zones occur in which climate zones:
Polar and sub-polar zone:
Temperate zone:
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Boreal coniferous forest
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Deciduous and mixed forest
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steppe
Subtropical zone:
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sclerophyllous shrubs
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Desert
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savannah
Tropical zone:
vegetation zone characteristics
Each vegetation zone has its own characteristics due to temperature differences. They must therefore be considered individually.
polar zone
The polar vegetation zone includes areas in the far southern and northern latitudes. The polar vegetation zone includes the tundra and the polar ice deserts.
tundra
The tundra is also called «cold steppes» and covers the subpolar zone of the Arctic. There are also small areas of tundra in South America. It is considered the transition zone between the arctic ice areas and the northern coniferous forests. The climate in the tundra is low in precipitation and cold with temperatures ranging from -50°C to 15°C. The vegetation has adapted accordingly.
Larger plants cannot survive under these conditions because the soils are impenetrable by permafrost and no water can be extracted.
Smaller growths such as shrubs, grasses and herbs can grow on the tundra during the warmer months of the year. This is possible because their growing seasons average only 2-3 months.
Temperate zone
The temperate zone includes the northern coniferous forest zones, the deciduous and mixed forests and the steppe landscapes. It lies between the subtropics with an annual mean temperature of 20 degrees Celsius and the polar zone with an average temperature of 10 degrees Celsius in the warmest month.
Boreal coniferous forest
The northern coniferous forest is also called «taiga» and is the northernmost vegetation zone in which large trees and shrubs also grow. In this vegetation zone, the average temperature is -15°C – 0°C. Precipitation values are on average below 600 mm, so they are rather low. The boreal coniferous forest is found in Alaska, Canada and northern Europe.
You can enter the amount of precipitation in millimeters (mm). With «1 mm of precipitation» you mean the equivalent of 1 liter (L) of precipitation per square meter. Put simply, this means: 1 mm = 1 L.
As the name suggests, most of the vegetation in this zone consists of conifers. These include spruce, fir, pine and larch. In some places it can also happen that deciduous trees grow. On the forest floor one finds mainly mosses, lichens and herbs.
Since the temperatures in the boreal coniferous forest zone are often below 0°C and the ground then freezes over, the trees cannot absorb water through their roots at this time. So that as little water as possible evaporates, they have needle leaves instead of deciduous leaves. Because of the smaller surface area, less water is evaporated from needle leaves. In addition, the waxy layer of the cuticle protects the needle leaves from cold damage.
Deciduous and mixed forest
The deciduous and mixed forest zone is the vegetation zone in which Germany, Austria and Switzerland are also located. As in the tundra and the coniferous forest, here too there are distinct seasons.
The climate is temperate, with average temperatures of 6°C – 14°C. At 600 – 900 mm, precipitation is higher than in northern vegetation zones and is distributed throughout the year so that there are no dry periods.
Ideal growth conditions prevail here for deciduous trees such as beech, oak and spruce.
The deciduous trees shed their leaves in autumn. Before doing so, they strip the leaves of as much nutrients and chlorophyll as possible. The substances are then stored in the trunk, branches and roots so that they can survive the winter.
Trees also drop their leaves because otherwise too much water would evaporate through the leaves. The trees would then dry up. Since the ground often freezes in winter, the trees cannot absorb as much water at this time of year.
Unfortunately, most such forest areas are used economically, which is why the biodiversity in these forests is not as pronounced as it used to be.
steppe
The steppe, like the deciduous and coniferous forests, is assigned to the temperate zone. With an average temperature of 3°C – 8°C, the temperature is acceptable for larger plants. However, the growth of these is prevented by the long dry periods. Average precipitation here is only 300 mm.
For this reason, the vegetation in steppe landscapes consists mainly of tall grasses and herbs that can reach a height of up to two meters. The amount of precipitation here is not enough for trees or larger shrubs.
subtropical zone
The subtropical climate zone is characterized by low rainfall and high temperatures in summer and mild winters. The sclerophyllous zones, deserts and savannahs belong to the subtropical climate zone.
sclerophyllous shrubs
The vegetation zone of the sclerophyllous shrubs has characteristics that force the plants to adopt certain protective mechanisms. The summer are hot and dry with an average temperature of 25°C. The precipitation falls with 300 mm – 700 mm mostly in the winter months, just at the time when the plants cannot absorb the water. The average temperatures in the winter months are 7°C – 12°C.
For this reason, the vegetation in sclerophyllous regions has adapted accordingly: sclerophyllous trees such as olive and laurel trees have small, hard leaves that are well protected against dry periods. They also have an extensive root system to gain enough resources from the nutrient-poor soils.
Desert
You can easily recognize desert areas: Due to the extremely high temperatures and the long dry periods, deserts are almost completely devoid of vegetation. The few plants that grow in the desert have adapted to the region with small leaves and deep roots. The annual rainfall here is only 50 mm – 200 mm.
Deserts are inhabited by cacti and succulents. Due to the limited availability of water and moisture, they have special protection mechanisms against evaporation and store their water inside.
tropics
A total of five vegetation zones are characteristic of the tropical zone. These include three different types of savannah and the tropical rainforest. In the following sections, the respective characteristics of the vegetation zones are presented in more detail.
savannah
Like the sclerophyllous regions and desert regions, savannahs belong to the subtropical zone. You are between the desert and the tropical rainforest. There are three types of savannas, differing in climate. For this reason there are three different vegetation zones of the savannas:
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thornbush savannah
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dry savannah
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wet savannah
thornbush savannah
The thornbush savannah is the driest type of savannah with only 250 mm – 500 mm of precipitation per year. The average temperatures are between 25°C and 35°C.
dry savanna
In the dry savannah, the precipitation is 500 mm – 1000 mm slightly higher than in the thorn bush savannah and the average temperatures here are 25°C – 30°C.
wet savannah
As the name suggests, the wet savannah is the wettest type of savannah. The precipitation is highest here with 1000 mm – 1500 mm. The average temperatures are between 25°C and 28°C.
Basically, the vegetation in savannas consists of one open tree layer and one covering the ground herb layer. However, the three savannahs differ in some ways in the type of vegetation. While bushes mainly grow in thorn bush savannas, trees can only really grow in dry savannas.
Tropical rain forest
The tropical rainforest is characterized by high rainfall, which is spread over the entire year. The precipitation values here are mostly over 2000 mm and can also reach 10000 mm per year. The temperatures are also almost constant at 25°C. The combination of these factors resulted in the most diverse variety of species having developed in the rainforest:
There are huge trees that grow up to 40 m tall, but also the forest floor is covered with a variety of herbs, shrubs and smaller trees.
Vegetation Zones – Occurrence
There can be several vegetation zones within a continent. You can now see what that can look like in Europe, Africa and then in the northern hemisphere.
The different vegetation zones in Europe
The European continent is divided into three climate zones. The north of Europe forms a sub-polar zone, the mid-latitudes a temperate zone and the south of Europe with its Mediterranean area a sub-tropical zone. The vegetation zones are divided accordingly.
In the north of Europe there is mostly a treeless tundra. A taiga with many coniferous forests prevails over Scandinavia, Finland and northern Russia. To the south there is a mixed forest zone, which merges into a deciduous forest zone. The steppe then begins at the Black Sea.
vegetation zones of Africa
At the equator are the always humid tropics with high rainfall and constant temperatures of 25°C. To the south and north of the equator are the periodically humid tropics, which include the dry savannas and wet savannas….