Ecological restoration aims to recreate a natural ecosystem on a site - either the system that historically would have been present there (e.g., putting a forest back on land that has previously been clearcut) or, where the land has been changed so much that it can no longer support the original type of ecosystem (e.g., where a wetland has been permanently drained), the type of natural ecosystem best suited to the site's new conditions.
There are two types of ecological restoration - active and passive.
Active restoration uses a hands-on approach to try and help nature come back to a site. It often involves plantings, weeding and other management practices.
Passive restoration, on the other hand, depends on the natural succession of ecosystems to help bring back the appropriate type of system to a site. For instance, in an area that would naturally be a forest but is currently a field, being left to develop on its own will typically result in the initial growth of shrubs and saplings of trees that enjoy full sun. Over time, shade tolerant trees will start to grow up under those, until eventually the site hosts a full-grown forest.
The Society for Ecological Restoration's Primer on Ecological Restoration provides an excellent resource for individuals interested in the art and science of helping to restore natural ecosystems. For more information on the ecology of Acadian Forest Region, visit the World Wildlife Fund.