Natural forest in South Africa occurs in small, scattered patches. Many alien tree and shrub species have been recorded from the forest environments but few are true forest invaders. Concepts have been developed around the natural disturbance regimes affecting forests and how changes in these affect the invasion potential of invasive species. Natural fires in the landscape confined forests to fire refugia. Changing the fire regime through conservation, commercial forestry, intensive agriculture, and urban development allowed trees to grow back into the landscape. Invader plants, typical pioneers in their natural environment, were the first to become established. They are intolerant of shade but nurse the establishment of shade-tolerant forest species. Inside the forest, the natural small gaps (<150 m²) prevent the establishment of shade-intolerant invader plant species. This knowledge provides the basis for guidelines to manage plant invasions by controlling gap size inside the forest and to convert invasions to regrowth forest on the outside. This approach also gives the opportunity to combine invader plant control, forest rehabilitation, and small business in rural environments.

Additional index words: Forest rehabilitation, shade tolerance, small business, succession.