* A jungle is a man-made thing. It occurs when people cut down the trees and burn the land, farm it for a while and then abandon it.
* Native plants now all compete to use the land and for a while huge numbers of plants grow (the native plants can, of course, live in poor soil). This gives an impenetrable thicket called a jungle.
* In time it will change, trees will shade out the ground, it will then open out and return to rainforest.
