September 11, 2020 5 min read

Ever wonder what happens after forest fires? Fire ecology can help explain.

Fire ecology is the study of the role of fire in ecosystems. Fire ecologists study the origins of fire, what influences its spread and intensity, fire’s relationship with ecosystems, how controlled fires can be used to maintain ecosystem health, and what happens in nature after fires. 

As the current forest fires tear across California, the Pacific Northwest, and many other parts of the world, we’re already thinking about what happens next. Some areas will be able to regenerate on their own, while others will require swift reforestation if they are to have any chance of forest fire recovery. 

    So what gives — why can some places recover after forest fires naturally, and others can't?

    Answering that question requires learning from the experts, and looking at the biotic (related to living things) and abiotic (not derived from living organisms) components of an ecosystem. 

    Once it's safe to do so, environmental professionals assess the scope of the damage, asking questions like these: 

    • How many trees were killed? 
    • Was the seed stock destroyed? 
    • How is the local climate affected? 

    Will the ecosystem be able to regenerate on its own? If it can do so with minimal help, great! If not, that's where we come in. 

    But before tree planting can take place, a few things usually need to happen:

    • Removing extra debris like snags (dead trees) and brush that will provide fuel for future fires, while leaving some to provide wind protection and improve water retention for newly planted trees. Some wildlife species, like the black-backed woodpecker, also rely on snags to nest and forage the insects that are drawn to these recently killed trees.
    • Assessing the health of the soil, the erosion risk, and remediating as needed. Fires often improve the nutrient profile of the soil by breaking organic matter down into a usable form. But they also remove the most effective anchor — trees — holding everything together, which increases the risk of everything washing away. 
    • And determining what tree species will provide the most benefit — for example, during a recent effort to reforest parts of British Columbia that were destroyed by historic wildfires, we included Trembling Aspen, which has a high water content and helps slow the spread of wildfires by creating a natural protective barrier.

    When all the questions are answered, and it's determined that reforestation would be the best approach to support landscape recovery, that's when we plant trees.

    But if the damage isn't too severe, nature might just be able to bounce back on its own.

    How Trees Adapt to Fire Graphic

    Okay, now you may be wondering how anything can survive severe fires

    But it's important to remember that in some ecosystems, fire has historically played an integral role in shaping and maintaining the landscape. As a result, many native plant and animal species have developed incredible strategies to withstand blazes. 

    California’s giant sequoias depend on fire to reproduce: their serotinous cones, glued tightly shut with pine resin, require it to release the mature seeds inside. And their thick, fire retardant bark protects sensitive inner tissue, allowing it to withstand low-intensity surface fires. Other species with fire-aided dispersal strategies include jack pine, table mountain pine, and lodgepole pine (one of the first to grow after a fire). And many chaparral plants like coffeeberry, long sepal globemallow, and snow brush have coated seeds that need direct or indirect contact with intense heat, smoke, and/or nutrient release to signal germination. 

    Underneath the soil often lays a rich seed bank just waiting for the right opportunity. Species like Indian paintbrush, scarlet gilia, Oregon sunshine, and Washington lily are just a few examples of beautiful fire-activated wildflowers. Even fungi can benefit — and the experienced mushroom hunter knows that recent burn sites are the best place to find morels and boletes!

    Indian Paintbrush

    When gaps are opened in the canopy, some, like pine grass, get access to more sunlight and respond by flowering. When brush is cleared from the understory and gaps of bare soil are created, plants like fireweed readily colonize them with their lightweight, wind disseminated seeds. And sometimes, fire changes the composition of the soil itself, volatilizing nutrients like nitrogen. When this happens, plants like Lupines, which typically grow in nitrogen-deficient soils but are able to fix it, multiply quickly.

    Fire Hawk

    Animals have some pretty amazing adaptations too. In Australia, fire-foraging birds actively start fires to smoke out mammal and insect prey. These so-called fire hawks — black kites, whistling kites, and brown falcons — swipe burning sticks or grasses from fire areas (and sometimes even human cooking fires!) and drop them into

    unburned areas to set them alight. They are, of course, a notable exception — most wildlife species will use intimate knowledge of their home ranges to outrun or fly away from fires. Those that aren’t as quick on their feet, like ground squirrels, frogs, and ants, will burrow deep underground or shelter under rocks and downed logs. Others will wait out fires within nearby bodies of water, returning to assess damage and score newly released nutrients and habitats once it's safe to do so.

    No species is adapted to liveinfire, but many have found ways to rise, phoenix-like, from the ashes. They’ve adapted over thousands of years to the fire regime — or, fire frequency, intensity, and fuel consumption patterns — unique to their regions. But human activities like fire suppression, land degradation, and settlement, are shifting the balance from normal, low-mid range fires that help to keep ecosystems in balance to high-intensity blazes that destroy everything in their path. When the intensity is severe and nature isn't able to rebound, or when it does but as a lower-value bushland where a healthy forest used to be - that's where we come in to plant trees and help catalyze the natural process once again. 

    Want to test what you've learned? Take the quiz below to test your forest fire knowledge. 

    Want to help us restore forests that have been destroyed by wildfires? Learn more about what we're doing to help and plant a tree in California today!

    We plant trees on 4 continents around the world. Want to choose where yours are planted?

    by Meaghan Weeden

    Forest Whisperer

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