Forest ecosystems are all around us, they’re responsible for producing the world’s oxygen and contain many of the living species in the world, but how do they do it? What structures do they have that allow them to provide resources and homes to so many living things?
First, let’s discuss the definition of an ecosystem since the term is a bit vague:
- An ecosystem is a group of living and non-living things working together to maintain each other and interacting through the transfer of energy and materials. An ecosystem includes all plants, animals, and any organism, along with the abiotic features of the area like the air, and water.
So, an ecosystem is not just plants and animals, it’s every living and nonliving thing. The ecosystem also includes abiotic systems like climate and topography. More specifically, a forest ecosystem is an ecosystem that encompasses an area with relatively dense tree cover.
We’ll now answer the following questions about forest ecosystems:
How Are Forest Ecosystems Structured?
The “structure” of an ecosystem refers simply to the parts of the environment and how they are related to each other. It is often drawn in a diagram–think food webs–but the structure is much more complex in reality.
Forest Ecosystems and Energy
Forest ecosystems, like all ecosystems, are organized and structured through interrelated parts that exchange energy. The energy is transferred via two main routes:
- The sun: plants capture energy from the sun and turn it into food
- Biological matter: plants and animals are eaten by other plants and animals
So the sun is the primary source of energy in a forest ecosystem and food like plants and animals are secondary, tertiary, or quaternary forms of energy.
Because all forms of life indirectly or directly require the sun’s energy, we can see the sun as a sort of foundation on which the structure of the forest ecosystem is built. Without the sun’s energy, no living thing could exist.
Generalized Forest Ecosystem Structure
The structure of a forest ecosystem is incredibly complex and it would be nearly impossible to map out every energy transfer among every abiotic and biotic feature of a forest. But lucky for us, we have a great general idea of how this process works. Let’s take a look at an example…
- The sun’s light shines and is absorbed by grass and turned into energy via photosynthesis
- The grass is eaten by a mouse and converted to energy
- A hawk eats the mouse and turns it into energy
- The hawk eventually dies, and the decomposers (fungi, microarthropods, etc). Turn the hawk’s body into energy
- The grass uptakes the energy
Of course, we could point to many more relationships here, but the main illustration is that the ecosystem is structured around energy. You can follow the path of the energy from the sun to the soil. Here’s the path that the energy traveled in this example:
Sun → Grass → Mouse → Hawk → Fungi
Note that water, the climate, the soil, and the air are all acting as supports here that are necessary for the continuation of this energy transfer chain.
For more detailed information on forest ecosystem structure, check out this article: What Makes Up a Forest Ecosystem?
Why are Forest Ecosystems Important?
Forests are home to an estimated 80% of the life on earth and occupy over one-third of the earth’s land surface. All the forest ecosystems in the world can be seen as one great big machine, taking in carbon dioxide and pumping out oxygen, providing us with fresh, breathable air.
In this section, we will talk about the function of a forest ecosystem on a few different scales, including a forest’s impact on:
Impact of Forest Ecosystem Function on Biodiversity
Correct ecosystem functioning is essential for the maintenance of biodiversity in the system. But what exactly is biodiversity?
- Biodiversity refers to the number of different living species within a given ecosystem
As we know based on the discussion of the forest ecosystem structure, every living thing in a forest relies on something else. In the example above, if the mouse were driven to extinction, the transfer of energy would end there. The hawk would have to find other food, and so would the fungi.
The function of a forest ecosystem is to provide resources and energy to living things. So, a forest ecosystem is also functioning to protect biodiversity by keeping those living things alive.
Why is Biodiversity Important?
While forest ecosystems function to maintain biodiversity, biodiversity also functions to maintain ecosystems.
Biodiversity ensures that there is a species available to fill each ecological niche.
- An ecological niche is an area, resources, and food that a particular living being lives in or uses
The ecosystem itself provides the living thing with its niche, and the living thing cannot live outside of its niche. The ecological niche provides that other living things are consistently able to rely on that species to fulfill their ecological niches.
For example, the mouse’s ecological niche is that it lives in the ground, drinks from the stream, and eats grass. All other living things occupy their niches relative to the mouse, and some species cannot live without the mouse.
- Forest ecosystems are made up of delicately interrelated parts (living and nonliving), each with their own role in the system. One part cannot exist independently; each part relies on the other directly or indirectly.
Impact of a Forest Ecosystem on Other Ecosystems
Forest ecosystems provide nutrients and resources to other ecosystems that are interconnected around the world.
This is why carbon released in the US may travel through the atmosphere and eventually be used by trees in the Amazon rainforest.
Humans interact with forest ecosystems more directly by extracting resources (which also often travel around the world).
Forest ecosystems interact with other ecosystems in these ways:
- Ecosystem services: all the resource, regulatory, and cultural benefits that an ecosystem provides for itself and other species or ecosystems
- Nutrient and matter cycling: air, water, organisms, and nutrients flow in and out of forests to and from other ecosystems (cycling materials can also be an ecosystem service)
Forest ecosystems function to provide services within the ecosystem, as well as outside of it. Here are a few examples of matter cycling these are all ways that forest ecosystems are connected to each other and other ecosystems:
- Rivers and streams carry water in and out of ecosystems
- Air carries pollen, spores, and seeds from one ecosystem to the next
- Animals carry bugs, microorganisms, seeds, and waste from one ecosystem to another
All ecosystems are to some extent dependent on other ecosystems, and the closer they are together, the more they depend on each other. For example, two neighboring ecosystems may both depend on the water, animals, and certain other resources that travel between them.
Each forest ecosystem also impacts other ecosystems indirectly through larger-scale impacts like climate. Let’s now zoom out and talk about the earth as a whole.
Impact of Forest Ecosystem on the Global Ecosystem
The great thing about ecosystems (and systems thinking in general) is that we can imagine systems at any scale we’d like. So, the tip of a cotton swab is an ecosystem, and so is the whole globe, it just depends on what perspective we take.
Because the earth is one global system, each ecosystem within it has an effect on the state of the global system.
So, how do forests affect the global ecosystem? Here are a few big ways:
- Nutrient cycling: Forests help to process and regulate the global supply of important nutrients like oxygen, phosphorus, and nitrogen.
- Oxygen and carbon dioxide balance: Forests are crucial for regulating the amount of carbon dioxide and oxygen in the environment. We rely on global forests to process our carbon dioxide and provide us with oxygen.
- Climate regulation: Carbon dioxide is a greenhouse gas largely responsible for the diminution of the atmosphere and therefore, climate change. Since forests process carbon dioxide and turn it into oxygen, they are essential to regulating the climate.
- Maintaining global biodiversity: Forests don’t just function to maintain biodiversity within themselves, they also help maintain biodiversity globally. Forests provide materials necessary for the continuation of every living thing on the planet.
Impact of Forest Ecosystems on Humans
Forest ecosystems are essential for human life. These are the ecosystem services that forests provide us with, according to the USDA:
- Provisioning services: food, water, timber, material goods
- Regulating services: regulating climate, water, disease, and pollination (discussed above)
- Supporting services: soil formation and nutrient cycling
- Cultural services: education, beauty, heritage, and recreation
We can see here that forests provide us with tangible benefits like water and timber, but also with intangible benefits like education and beauty. Human life and society would not exist today without the forest ecosystems of the earth.
- Forests are structured around the transfer of energy and materials, beginning with the energy from the sun which is transferred through different living things and supported by abiotic features like water and minerals.
- Forest ecosystem structure is set up to maintain the biodiversity of the system because every living and nonliving thing supports every other living thing in some way.
- Forest ecosystems provide nutrient and matter cycling that bring abiotic and biotic materials in and out of the forest, to and from other ecosystems.
- On a global scale, forests act as a climate regulator and help to maintain biodiversity worldwide.
- Forests provide many tangible and intangible benefits to humans that we cannot live without.