The four main characteristics of the tropical rainforest habitat are: abnormally high annual precipitation; high typical temperatures; highly unfortunate soil; and heightened levels of biodiversity.
Because sunlight is essential for photosynthesis, where plants create their nourishment from sunlight, carbon dioxide, and moisture, plants grow towards it. In the equatorial jungle, plants compete fiercely for sunlight and moisture.
As they grow bigger and higher, the trees and plants that can receive enough light and moisture advance relative to others that must compete with them for these resources. The accessibility of daylight to smaller trees is therefore severely restricted because higher trees usually block sunlight from shining on them. Therefore, we have a variety of trees with different levels of complexity.