Red passion vine flower
PICTURES: Plants

Rainforest plants

The forest floor of old-growth rainforest is rarely the thick, tangled jungle seen in movies and adventure stories. It is usually relatively clear of dense vegetation due to the deep darkness created by the canopy. So instead of choking vegetation, a visitor to the rainforest will find large tree trunks interspersed with hanging vines, countless seedlings and saplings, and a relatively small number of ground plants.

Because rainforest trees are in a constant battle for access to sunlight, they grow straight and tall, only branching near the top of their long, pole-like trunks. Because of the intense sunlight in the tropics, many plants have adapted to living in the canopy. Some of the most common are epiphytes, which are plants that attach themselves to trees. In some forests epiphytes can be very abundant—over 2,000 epiphytes may be found on a single tree.

While the idea of a plant that lives on another plant may seem strange, many house plants are by nature epiphytes. Well-known examples include bromeliads or “air plants” and some kinds of orchids.

Rainforests have a huge variety of tree species. It is not unusual to find more than 200 different types of trees in a couple of acres of rainforest.

Diversity protects species. A species that becomes too abundant in natural forests faces the threat of a predator adapting to exploit its abundance. For example, in the Amazon the failure of rubber tree plantations, where only a single species is grown, is due to a fungus that feeds on the tree. In the natural rainforest, rubber trees are widely dispersed so the fungus can never wipe out more than one individual tree at a time. That’s why plantations and single-species agriculture are so susceptible to pests and require toxic chemicals.



By Rhett Butler

Date published: June 24, 2004 | Last updated: March 21, 2014