There are about 2500 species of lianas in the world, which all come in various shapes and sizes. The name liana is not a taxonomic group, but a group of plants which grow in a particular manner. There are two major functional groups, those which start off life rooted in the soil andborrow other trees to gain height, and those which start off life in the canopy and drop roots down to the ground. Neither type is a parasite on the trees they climb; they simply use their surroundings for physical support. However, trees can grow faster without lianas, because they have more exposure to sunlight. In some places lianas account for 40 percent of the canopy cover!
Lianas also grow between trees, forming important sky bridges which are utilized by a number of animals and insects. The link they create between trees makes it harder for loggers to cut down only the trees they want to sell, leaving the rest standing. As a result, one tree cut down leads to the surrounding ones also falling because of the liana connections. Liana leaves look different depending on where they grow. Those growing on tree trunks are flattened to the trunk, whereas those in the canopy grow out away from the tree aiming for a better angle to intercept sunlight.