In some national parks, controlled fires are maintained by firefighters. which of these is one of the major reasons for using controlled burns to maintain certain ecosystems?

to allow the spread of insects that provide food for animals
to rid the forest floor of accumulated deadwood and brush
to give nonnative plants a chance to colonize the region
to replace mature plants with saplings of the same species

to rid the forest floor of accumulated deadwood and brush

Explanation:

A fire can be a natural or induced limiting factor which is expected to reduce the growth, abundance and distribution of the population of species in an ecosystem.

In human induced fire certain regions of the forests are set on fire and in some regions which exhibit unwanted shrubs and grasses in control amounts to eradicate those shrubs and grasses.

On the basis of the above explanation, to rid the forest floor of accumulated deadwood and brush is the correct option.