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Biotic and abiotic factors of the forest

Forests are terrestrial biomes in which, according to various influencing variables, we can identify different ecosystems, each characterized by certain abiotic and biotic factors.

If you want to know what relationship exists between the biotic and abiotic factors of the forest , keep reading this AgroCorrn article, where you can also delve into the different types of forests that exist, their characteristics, as well as the flora and fauna they harbor.

Biotic factors of the forest

Biotic factors or living beings are all the animals, plants, fungi, bacteria and other microorganisms that inhabit an ecosystem, as well as the relationships that exist between them. In forests, the plant or animal species that we can find depend on the physical-chemical characteristics of the environment, therefore, in the following sections, we explain how the fauna and flora vary according to the different types of forests that exist.


Considering the flora of the forests , the following plant formations stand out:

  • The trees . These plants with woody trunk are very important, on the one hand, due to the large number of regulatory ecosystem services they provide (purification of the atmosphere, erosion control, water purification, climate regulation) and, on the other, Due to the supply services that play an important role at a socioeconomic level (they are a source of wood, charcoal, paper pulp, resins, ornamental or edible fruits and flowers).
  • The bushes . They are woody plant formations, are important sources of biodiversity and protect soils.
  • Herbaceous plants . Despite not having as much value for society as other plant formations, these grasslands are very important because they increase soil fertility and favor its conservation, as well as contributing to the pollination process.

In relation to vegetation, there are other biotic factors related to the structure of the forest and its regenerative capacity, such as:

  • Seedling banks, made up of small woody plants that grow only a few centimeters per year and participate in the replacement of trees or other plants of higher altitude, filling eggs or forming new canopies, after great disturbances in ecosystems, such as the fires or deforestation activities.
  • Seed banks or sets, on the other hand, can be found in the soil and are potentially capable of replacing annual plants.


Forests are great sources of biodiversity, where animals make up a complex food chain. Taking into account the trophic networks, which are nothing more than the set of these chains, animals occupy some trophic levels or others, depending on what they feed on, and can be classified as primary consumers (they feed on plants), secondary and decomposers. . Decomposers can be heterotrophs or transformers (bacteria and fungi) and autotrophs or mineralizers, capable of generating organic matter and releasing inorganic salts to the environment.

Some examples of animals that live in forests are: squirrels, deer, mice, foxes, frogs, trout, eagles, bats, etc. Here you can find out much more about what animals live in temperate forest .

Relations between organisms

Considering that, according to the definition provided at the beginning of this section, the interactions that take place between living beings are also part of the biotic factors of an ecosystem, in this case of the forest, it is possible to speak of interspecific and intraspecific relationships.

On the one hand, interspecific relationships are those that occur between individuals of different species, which may be beneficial or detrimental to one or both participating parties. Meaning the symbols (+) benefit, (-) harm and (0) neither benefit nor harm, the interactions between species can be of:

  • Predation: organisms of one species, known as predators, feed on individuals belonging to another species, prey.
  • Parasitism (+, -): symbiotic relationship in which the parasite benefits and lives on the host, the latter being the one who is greatly injured. Depending on whether the parasite develops indoors or outdoors, we are dealing with endoparasitism or ectoparasitism (louse, for example), respectively.
  • Commensalism (+, 0): one of the species benefits while the other neither benefits nor harms.
  • Competition (-, -): organisms compete for the same resource in a situation where its abundance is scarce.
  • Mutualism (+, +): beneficial relationship for all the agencies involved. It can be optional (organisms can live without each other) or forced (they need each other to live). Example: myrmecophyte plants.
  • Symbiosis (+, +): mutualistic association in which there is a close long-term relationship between two different species, in order to obtain a mutual benefit for their survival (the most common example is lichen, a symbiosis between algae and fungus) .

On the other hand, when interactions take place between individuals belonging to the same species, we speak of intraspecific relationships. Among these, two major groups stand out:

  • Competition relationships for food, for reproduction, for social dominance.
  • Cooperative relationships, where individuals group together to increase the chances of survival. These associations can be gregarious (flocks of birds, schools of fish), in families, in colonies (polyps, bacteria, corals) or in societies (with castes for the division of labor, as occurs with ants, wasps or bees) .

We recommend you expand this knowledge by reading these other articles Biotic factors: what they are, characteristics, classification and examples and Trophic relationships of ecosystems .

Forest abiotic factors

The abiotic factors of the forest are those components that characterize the physical environment and that, unlike biotic factors, lack life. These elements that shape the biotope can be physical or chemical in nature. Among all we distinguish:

  • Soil temperature and humidity influence the mineralization processes of organic matter and, therefore, the amount of CO2 in the environment.
  • The luminosity or amount of light at ground level is one of the most important abiotic components of the forest, since photosynthetic autotrophic organisms and other living beings depend on it.
  • Mineral salts from the soil, essential for the development of vegetables. The saline balance is very important to avoid water stress in plants and alterations in soil microbial activity.
  • Air temperature: Extreme thermal situations can cause damage by frost or desiccation, generating stress and altering the growth rates of plant species, in turn influencing directly dependent species of fauna.
  • The type of soil varies depending on the structure and the physical forms it adopts, which conditions or limits the development of the vegetation and also the edafofauna present. For example, depending on their structure, we have sandy soils that do not retain water, unlike humiferous soils, so that the forms of life present in both types of soil can change given these hydric conditions.
  • Atmospheric pressure influences the development of organisms allowing them to live.

Learn more about abiotic factors: what they are, characteristics and examples by reading this other post.

Forest types

Depending on the climate of the forests and the altitude conditions, these can be very different. We differentiate several types of forests , the main ones are: boreal, temperate, tropical and subtropical.

Boreal forest

The boreal forests , also known as taigas, are located in the circumpolar region, between 50º and 60º latitude in the Northern Hemisphere. They constitute a third of the terrestrial forest surface and are strongly affected by temperature, which we can consider as a limiting factor for the development of life in these ecosystems.

In terms of biodiversity, evergreen plant formations such as conifers, firs and pines stand out. Although it is also possible to find deciduous plants such as birches, poplars and poplars.

As for the fauna of the boreal forests, the animals that inhabit them have adaptations that allow them to withstand the temperature conditions. For example, we find endothermic animals, capable of conserving their body temperature. Some of the most characteristic animals are: the brown bear, the boreal lynx, the crossbill, the northern kite, the caterpillars of the species Mesopolobus spermotrophus that feed on conifers, etc.

Temperate forest

The temperate forests are widespread in the Northern Hemisphere (Central Europe, the northern United States and Canada, eastern and northern Russia, Japan and China) and, to a lesser extent, for the Southern Hemisphere (New Zealand and Sudamérida) These forests are characterized by cold, wet and snowy winters and warm summers.

Among the most abundant vegetation are deciduous trees (beech, oak), conifers, and shrubs of the Ericaceae and Rosaceae families .

Regarding the fauna, widely threatened by anthropic activities, the presence of foxes, wolves, deer, woodpeckers, squirrels, etc. stands out.

Tropical forest

Located in the tropical zone, with warm temperatures and high humidity, the biotic factors of the tropical forest are very diverse, housing in them half of the species that exist on our planet.

According to the types of tropical forest that exist, the vegetation varies. In the dry tropical forest the grasslands (grasses) stand out, in the rainy one the tropical forests (leafy vegetation), in the monsoon there is an abundance of evergreen vegetation (eucalyptus, oak, bamboo) and in the flood zone the mangrove swamp.

In terms of fauna, in these forests it is possible to find monkeys, eagles, capybaras, crocodiles, vipers, tigers, gorillas, among other animals.

Subtropical forest

Close to the tropics, in these forests, which can be dry or humid, there is an abundance of broad leaf vegetation. In addition, the fauna present varies according to the different types of subtropical forests that exist, among which those of pine, premontane or montane forest, the subtropical humid and dry forests stand out.

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