Fuel as to Fern as what is to byrophytes?

Pioneer Species. Mosses are bryophytes and are often considered a "pioneer species" that will establish itself first in a forest that has been cleared by a forest fire. Ferns and other vascular plants are the "fuel" of the fires and burn out. Then when the forest begins to grow again, the non-vascular plants like the mosses (bryophytes) will grow first.