An oak savanna is predominantly a grassland with a sparse growth of oak trees. When oak trees lose their leaves, the leaves are resistant to decay but are very flammable. Mature oak trees have thick bark that makes them resistant to fire damage. Oak savanna ecosystems depend on periodic wildfires to thrive. How do periodic wildfires help to preserve this type of ecosystem? Select all that apply.
A) adds nutrients to soil D) thins forest floor of debris
B) encourages growth of non-native plants E) decreases biodiversity by killing wildlife
C) encourages the spread of fungal diseases F) allows competing species to thrive