Identify a pioneer species in glacier bay

Lichens, algae and mosses produce a fertile blanket on which succeeding plants can grow. Horsetail, fireweed, dryas and willow shrubs are the early pioneers. Alder, an important nitrogen fixing plant, followed by cottonwood, is usually the first tree to develop.

Explanation:

i think the miocene epoch spans the time from 23 million to 12 million years ago.

carbon atoms, hydrogen, oxygen, and nitrogen.