Plants are destroyed over a wide area, during an eruption. The good thing is that volcanic soil is very rich, so once everything cools off, plants can make a big comeback! … They can also die from famine, forest fires, and earthquakes caused by or related to eruptions
After a volcanic eruption, how quickly can plants start to grow back? One of the major factors to rehabilitate the particular area of land affected by the volcanic eruption depends on how much rainfall that area will receive. In some areas like Hawaii, where the island has continuous volcanic activities, there are flows that are only two years old but already have ferns and small trees growing on them.
Most probably that in ten years time they will be covered by a low forest. But on the other side of Hawaii, which they refer to ask the dry side of Hawaii, there is hardly any grass growing in sight. This can only mean that in order to determine how long the rehabilitation or regeneration of a particular place would take, you should also consider the climate activities in the area as well.