When a New England farm is abandoned, its formerly plowed fields first become weedy meadows, then shrubby areas, and finally forest. This sequence of plant communities is an example of

secondary succession

Explanation:

Communities are ever changing and are overtime being altered as a result of a process referred to as ecological succession. There are basically two types of ecological succession: primary succession and secondary succession. Primary succession is a type of ecological succession that involves series of changes on bare grounds, rocks or an area lacking soil.

Secondary succession on the other hand, changes occur on an existing community with vegetation after an earlier disruption has occurred in an already established ecosystem. It occurs in disturbed, disrupted or damaged habitats that were once colonized. Such disruption could be in form of wild fires, hurricane, an abandoned farmland etc, giving room for secondary succession to take place which gives rise to a new community.