The process of a fire starting and destroying the underbrush and trees in a forest is an important cycle in a forest's life, and helps improve the lifespan of the animals and vegetation living there. Many people believe forest fires, or any type of fire, is dangerous and obviously bad for anything living, which is where many people's belief on forests fires are wrong and inaccurate.
When a fire starts in a forest, the first part of the forest to burn is the underbrush, fallen branches and leafs from years before and the last fall. Lower branches and small shrubs burn as well, effectively cleaning the understory of the forest, leaving behind fertile ash that will later become the means for new growth. Because of the destruction the fire leaves behind, many people have been deceived by the appearance of what is left instead of looking to see that the ecosystem depends on this "destruction" to grow new life. For example many sub-species of pine trees need the extreme heat of the fire to melt the wax on their cones to let their seeds fall on to the ground so they may grow into trees later in life.
Another example of the good done by a forest fire is that fertile ash. All the shrubs and debris that was burned has become the ash that covers the ground, the nutrients in the ash is what newer, healthy greenery needs to grow, ash is also a great water absorbent, retaining it long enough for plants to use it. This new vegitation helps feed the animals that live within the forest, the small newly grown plants are both healthy for the large animals such as deer and stouts as well as it is providing food for the smaller occupants like mice and other small mammals. And because those herbivores get new food their populations expands providing in turn enough food for the predators such as wolves and bears that hunt them.
So in all, forest fires provide new fertile ground for plants to grow, which in turn