One hypothesis suggests anthropomorphic origins, those forest islands being earlier human farming of diverse useful, food-producing tropical plants and trees, collected and willfully inserted in suitable points of the grassland.
[2] These atypical mounts were first assumed to be the differential results of modern extensive animal farming on surrounding grasslands, loosening soil materials each year during recent centuries, while those tropical forest islands retained their initial elevation.
Defecations along circulation lines as well as active collection and spread of beneficial plants to increase future generation harvests and repel pests are documented.
Although this impact was previously thought to be minimal, Lombardo's study and dating shows over 10,000 years of extensive forestry engineering in this marginal area of Amazonia.
[5][2] Posey argued for the apêtê, or forest islands, composed of useful plant species, to be used as a viable locally-based model for reforestation of Amazonia.