Some might be amazed that the devastation of a forest fire could actually help ecosystems and forests, yet the fires really do in many ways. To understand, it is necessary to look at the bigger picture and look at the whole instead of just the parts.
Forests are dynamic and ever changing. What many don't understand though is that a forest proceeds through a natural cycle of diversity. When it is very young, it supports a great number of life forms. As the forest grows older, it isn't able to support as many. This is why there are far fewer plants and animals in an old growth forest than in a newer forest.
Plant species also change as the forest ages. When the forest is young, fast growing trees like aspen populate the forest. With age, these are replaced with slower growing species like oak, maple, pine, and fir. While all these trees reseed, these are all species that in varying ways block sunlight from reaching the forest floor. The sunlight is necessary for the young trees, grasses and bushes to grow.
This means that in older forests, there are fewer bushes and the trees grow more distant from one another. The land can't support as many animals because there are fewer plants for them to eat. Very old growth forests are doomed to die. It is an unfortunate fact of life and death.
What is more, branches, needles, and leaves produce a dense carpet than can even prevent seeds from getting to the soil so they can germinate. Ironically, this mat of debris is one of the things that cause a forest fire to expand.
Forest fires are destructive. There is no doubt about that at all. They wipe out trees, bushes, other plants, and wildlife. At the same time, though, they burn off the dense cover on the ground and open up the forests so new plants and trees can grow. They can revitalize a forest in much the same way that a farmer might till the soil and remove the weeds so his garden can excel.
At the same time, they also remove many pests that plague the forest, like pine beetles and borers.
What's more, the ashes left from the burning plants will enrich the soil, making the plants that grow there afterward even healthier than they otherwise might have been. Ash is high in potassium, needed for healthy roots. Some of the most vibrant and energetic forest growth occurs in areas that have been burned over by wildfire. Animal life is nearly always more abundant in these areas.
An example of this is an area of Oregon covering about 330,000 acres that burned several years ago. The only plants growing were grasses found here and there in pockets, and some badly singed bushes and small trees. Charred stumps dominated the landscape, and wildlife was gone. An area once well populated with deer, squirrels, birds, snakes, and lizards, was a barren landscape.
A year later, the change was remarkable. Grasses and new bushes were growing amidst the scars of the burned area. Squirrels and deer began to show up in large numbers, with the new food supply. Open growing conditions led to trees sprouting. The Forest Service helped with the replanting effort.
Today, the forest is once again home to a tremendous diversity in animal and plant life. Deer populations are even larger now than they were before the fire, and many animals now live there, which were unable to survive in the old forest.
Consequently, forest fires have an age reversing effect on the forest, turning back the clock a little bit so the forest doesn't die so quickly. This doesn't mean that forest fires should be encouraged, however. In many areas, man has suppressed fires for so long that the fuels are enormous and letting the fires burn will cause more damage than good.
In many areas though, the fires are permitted to burn until they cease naturally, under the close supervision of the US Forest Service and such entities as the BLM. Careful watch is kept so the fire doesn't burn out of control, however it is allowed to burn because it is recognized that there is an ecological benefit to the forest fire.
While forest fires can help ecosystems and forests, they should not be taken as a cure all, nor used and allowed to burn in all cases. In general, forest fires are beneficial. However, we must consider it on a case-by-case basis before just letting the forest burn.