Did the Mayans have plantations of cacao trees, or did they simply gather the fruit from cacao trees in the wild?
According to Cacao domestication I: the origin of the cacao cultivated by the Mayas, genetic evidence indicates that the cacao tree was cultivated from wild ancestors and improved over time.
Mayans were pretty good at agriculture, beyond the slash and burn methods that were used by many other tribes in the Americas during the same time period.
From Maya Agriculture
The Maya cultivated cacao in forest gardens in which every tree had a function. As a result, the trees that provided shade for the cacao also provided thatching and building material, fodder, oilseeds, wood, medicines, fruit and allspice. Careful management of the shade ensures that the cultivated cacao doesn't grow too quickly and thrives in a healthy and controlled environment that closely replicates the natural wild environment of the cacao tree.