How are Forests Affected When Trees Are Cut Down?

A forest isn’t a forest without trees, but how specifically does a forest respond when trees are removed during logging practices? Removing even a single tree from a forest can affect the ecosystem in the following ways: 

Levels Of Deforestation

Before we go into the effects of deforestation, let’s discuss some methods of deforestation. There are three main practices of timber harvesting:

  • Shelterwood: A stepwise process during which older trees are slowly removed to promote the growth of a specific species of tree
  • Clearcutting: Logging where every tree in an area is cut down
  • Selective Cutting: Logging where only valuable trees in a forest are removed and the rest are left

Of the three methods (discussed further in this article on “What Method of Logging Hurts Forest Ecosystems the Most”) clearcutting is by far the most destructive. While other methods can cause some of the effects we’ll discuss here, this article is mostly referring to the ecosystem effects of clearcutting. The more trees cleared, the more intense the effects discussed below.

Habitat Loss

Each tree in a forest provides habitat and resources to many different organisms including:

  • Birds
  • Squirrels
  • Insects
  • Fungi
  • Microorganisms

Each time a tree is cut down, all of the species using that tree lose their source of food or shelter. Cutting down a tree is habitat loss on a very small scale, but habitat loss leads to biodiversity loss. The more trees cut down in a forest, the fewer species will be able to live there.

Decreased Soil Health

Trees and soil rely on each other. The soil provides trees with nutrients from decomposer organisms, and in turn, trees provide the soil with nutrients they capture from the air like nitrogen. The fewer trees there are in a given forest, the fewer nutrient exchanges are happening and therefore the soil becomes unhealthy.

Unhealthy soil makes for an unhealthy ecosystem because it:

  • Inhibits the growth of new plants or trees
  • Increases vulnerability to erosion

Increased Flood Risk

Along with poor soil health, removing trees also increases flood risk for a forest. Tree roots are essential for maintaining proper drainage of rainwater. In a forest with poor soil health and no tree roots, water has nowhere to go and can end up causing disastrous floods where there otherwise would be no flooding.

Flooding in a forest can often be a natural process, but when it’s caused by deforestation, it can lead to the destruction of remaining organisms.

Higher Pollution Levels

Trees are the world’s most important anti-pollution machines. During photosynthesis, they absorb greenhouse gases and pump out oxygen. With each tree that is removed from a forest, there is less carbon dioxide being turned into oxygen and therefore, the forest (and the earth) is more polluted.

Key Takeaways

  • Trees are the most important element in a forest ecosystem. When trees are removed, this causes a drop in biodiversity, decreased soil health, incrased flood risk, and higher pollution levels.
  • While these effects can be seen on small-scale deforestation, practices like clearcutting magnify the damaging effects of tree removal.