The "Milpa" system is a traditional intercropping system of regional vegetables. Present day Mayan farmers cultivate this intercropping system through the practice of slash and burn together with small plots of other vegetable crops such as chiles, corn, beans, and squash. The Maya milpa entails a rotation of annual crops with a series of managed and enriched intermediate stages of short-term perennial shrubs and trees, culminating in the re-establishment of mature closed forest on the once-cultivated parcel. The milpa cycle involves two years of cultivation and eight years of fallow, or secondary growth, to allow for natural regeneration of vegetation. As long as this rotation continues without shortening fallow periods, the system can be sustained indefinitely.