Within a few miles of the 1980 Mount Saint Helens volcanic eruption, trees were snapped like twigs, plants were blown away, and the soil was covered with at least 8-12 inches of ash. We expect the plants that would first colonize this region would be pioneer plants:.

Plants with nitrogen-fixing symbiotic bacteria associated with their roots

Explanation:

Within a few miles of the 1980 Mount Saint Helens volcanic eruption, trees were snapped like twigs, plants were blown away, and the soil was covered with at least 8-12 inches of ash. We expect the plants that would first colonize this region would be pioneer plants with nitrogen-fixing symbiotic bacteria associated with their roots for example Legumes use nitrogen fixing bacteria, specifically symbiotic rhizobia bacteria, within their root nodules to counter the limitation, Rhizobia bacteria convert nitrogen gas (N2) to ammonia (NH3) in a process called nitrogen fixation.