Wildfires today are often dangerous and harmful to ecosystems because they are caused by human activity. However, when they occur naturally, wildfires can be ecologically beneficial.
This article will answer the following questions about wildfires in forests:
- How Do Wildfires Benefit Forest Ecosystems?
- What are Controlled Burns?
- When are Wildfires Bad for Ecosystems?
Wildfires can be beneficial depending on the circumstances, let’s now explore how they’re beneficial and what parts of the ecosystem they affect.
How Wildfires Benefit Forests
90% of wildfires today are caused by human activity. But without human intervention, wildfires serve to rejuvenate a forest ecosystem by doing the following:
- Supporting the growth of native plants by clearing invasive species
- Restoring nutrients to the soil
- Killing pests that harm trees
- Provide shelter and nutrients for animals
Wildfires may initially cause a drop in biodiversity in a forest ecosystem, but in the long term, they pave the way for a more diverse forest filled with native species. Let’s now talk specifics about how exactly wildfires are beneficial for forests.
How Wildfires Affect Plants
Wildfires will inevitably kill most if not all plant life on the forest floor. However, not all of this plant life is beneficial to the ecosystem. When a forest has gone a while without fire, it may have a build-up of invasive species.
- Key takeaway: Invasive plant species have a competitive advantage and may inhibit the growth of native species. Wildfires help clear invasive species to make room for native plants.
Once the fire has killed all of the plant species, native seeds land on the forest floor and have a chance to spring up because the understory is no longer shaded by invasive plants.
Wildfires and Soil
Wildfires help a new generation of plants and animals by restoring nutrients to the soil. As forest ecosystems progress, they will often grow a build-up of dead organic matter on the forest floor. Within this dead organic matter is tons of trapped nutrients. When a wildfire burns through this forest, the plant matter will burn and all of the nutrients will be returned to the soil in the form of ashes.
The ashes from the burnt organic matter will create a more fertile soil to serve as food to the new generation of plants that sprout up following the forest fire. They are especially helpful to native plants that may require more nutrients to grow in comparison to competitive invasive species.
Wildfires and Trees
Not all trees in a forest will die during a wildfire. Trees in areas where wildfires are a common occurrence such as the Coast Live Oak tree, and Beech tree which have natural fire resistance and can survive a forest fire. Some trees even require wildfire to grow. Many pine species have seeds that must be exposed to fire to germinate.
Fires also kill off pests and promote the growth of healthy young trees. Old trees that have insect or fungal infestations will die in the fire, and the new nutrients and wide-open canopy will make room for the next generation of young, healthy trees.
Do Wildfires Kill Animals?
Very few animals in a forest during a wildfire will die. Animals will choose one of two defenses from wildfires:
- Burrowing into the ground
- Escaping to a different forest
When they emerge or return, these animals will be in an ecologically diverse habitat in which the plant life will be able to better support them, and possibly some new mammals to the ecosystem. Many animals will also make their new homes in the fallen trees after the fire.
Why Controlled Burns are Necessary
Controlled or prescribed burns are intentionally set by foresters for the purpose of ecosystem management. They are employed for the following reasons:
- To prevent a wildfire: Since controlled burns are done under very safe conditions, they are used by foresters to prevent a wildfire that may be larger than necessary. Controlled burns may be used in a very dry forest area that ecologists think is susceptible to wildfire so that they can control how exactly how large the fire is and ensure it does not harm anyone.
- To remove invasive species: Controlled burns may also be necessary for a forest where invasive species have taken over. The fire will kill off the invasive insect or plant to make way for new, native species to grow in that area.
Prescribed burns allow foresters to simulate the natural process of burning without having to deal with out-of-control wildfires that can harm humans and our homes.
When are Wildfires Bad for Ecosystems?
Wildfires today are known for being incredibly harmful. Wildfires are increasing in severity and intensity due to:
- Logging (leaves flammable debris on forest floors)
- Increasing temperatures
Because of these conditions, wildfires are occurring more frequently than they would without these human impacts on forest ecosystems. Fires that are too frequent, too large, or too wide can be detrimental to forest ecosystems.
Fires of this nature can cause:
- Increased erosion: Intense heat can cause soils to dry out and become unable to absorb rainwater which causes erosion.
- Increased risk of flooding: A forest with eroded, dry soils and few trees are susceptible to flooding if there is heavy rain because the forest no longer has an irrigation system of roots and healthy soil to absorb rainwater.
- Fewer native species: If fires are too frequent, they may end up killing off native plants because they have not had enough time to grow in between fires.
- Poor air quality: Wildfires release a huge amount of greenhouse gasses and ash into the air. Fires that are very large and intense can decrease air quality in the region for months, inhibiting the health of the plants and animals attempting to return after the fire.
Uncontrolled, human-caused wildfires are devastating to forests themselves, and to human life. Controlled burns are necessary to prevent these fires and to maintain healthy ecosystems.
- Wildfires are a natural process that many forests rely on to control invasive species, increase soil health, kill pests, and increase biodiversity in the long term.
- Controlled burns are human-prescribed wildfires that allow for the ecological benefits of wildfires without risking a large out-of-control fire.
- Most wildfires today are caused by the effects of climate change. Wildfires that are too large, too frequent, or too widespread can cause serious damage to a forest ecosystem and controlled burns are necessary to prevent dangerous fires.