The most extensive tropical rainforests are in the Americas...hike through them and hide under the continuous canopy above you. Trees are the main life form and form the framework of the forest and support an abundance of climbers, orchids, and other tropical plants, adapted to the microclimatic conditions of the different zones of the canopy, from shade lovers in the gloomy, humid lower levels, to sun lovers in the brightly lit, hotter, and drier upper levels.