A catastrophic forest fire will often decimate an old growth forest so that it will take years for the forest to recover. The devastating bush fires in Australia a few years ago are examples of catastrophic fires. While catastrophic forest fires are best to be prevented, occasional forest fires are necessary so that a forest maintains a healthy ecosystem. When studying the effects of a forest fire on a forest’s ecosystem it is important to remember that a forest isn’t comprised of only trees. A forest also contains creeks and ponds, wildflowers, animals, birds and fish.
There are two types of forests; old growth and new growth. Old growth forests don’t support as many healthy species as new growth forests. Old growth forests consist of many mature trees with tall canopies that tower over the entire forest. These tall canopies block out sunlight, which seeds need to germinate. An old growth forest can’t support as many animals because the land doesn’t produce enough food. Many animals then migrate to new areas in search of food.
Dense forests like old growth forests are prone to more catastrophic fires because of dead needles, leaves and logs that are allowed to build up on the forest floor. Old growth forests are also prone to insect infestation due to their denseness. One solution that scientists use to clear out old growth forests to restore a healthy ecosystem is prescribed or controlled burning. Most of us grew up watching Smokey the Bear, and listened closely as he told us, “Only you can prevent forest fires.” And while Smokey was right, in that, we all need to be careful when we are hiking or camping, not to start a fire, scientists sometimes will intentionally start forest fires to encourage the continued health of the forest.
Trained specialists, primarily scientists, start prescribed fires. They make scientific decisions as to what gets burned, where and how. Prescribed burning turns an old growth forest into a new growth forest by thinning the number of mature trees. After a controlled burn, sunlight again is free to shine on a forest floor encouraging germination of fallen seeds. Controlled burning reduces fuel (mature trees) and fuel ladders for catastrophic fires. It also reduces competition among the trees for water and light allowing new seedlings to take root in ash enriched soil, thus beginning a new growth, healthier forest.
Animals and plants adapt well to controlled burns. Animals will flock to a new growth forest after a burn because of the amount of vegetation sprouting up out of the enriched soil. This helps promote the recovery of threatened and endangered species. Trees such as Jack pines and Lodgepole pines have resin coated cones, much like tar. This resin coating is only melted by fire. After a forest fire these cones open and the seeds spread over the forest floor producing seedlings that wouldn’t exist without a fire.
Prescribed burning isn’t without controversy. Many people were outraged in 1988 when a controlled burn was started in Yellowstone after a lightning strike set off a blaze in an old growth forest. In attempt to rid the forest of dense undergrowth and some mature trees, a controlled burn was started. The fire got out of control and firefighters were called in to help put the fire out. It was the most costly fire in US history costing $120 million to put out. Many people feel that Mother Nature alone should be able to maintain a forest’s healthy ecosystem.
And in fact, sometimes Mother Nature does just that. Lightning strikes start a few thousand forest fires per year in this country. Some of these fires burn out on their own and others have to be put out by wildlife management officials or firefighters. Forest fires cost the US and Canada millions of dollars per year to fight, however; knowing that Mother Nature and wildlife officials create these fires for a purpose should give us a new appreciation for the complex, delicate ecosystems of healthy forests.