EXPLANATION/ANSWER:
Major causes of ecological succession:
>MAN-MADE - Actions of humankind that causes destruction of habitats like accidental forest fires due to fireworks display, deforestation to clear a forest to become a subdivision, or create a man-made lake in the middle of the city.
>NATURAL - Naturally occurring phenomena like forest fires due to the dryness and hotness of the area, hurricanes, typhoons, and volcanic eruptions.