Explore the Tropical Rainforest
The Garden is home to indoor collections with tropical rainforest plants from around the world. Tropical rainforests are wet, warm habitats with dense tree cover which receive more than 80 inches of rainfall a year. They are located between the Tropic of Cancer and the Tropic of Capricorn where average temperatures are warm and days are long. Because of the consistent mild and humid conditions, tropical rainforests have incredible plant and animal diversity. Many scientists believe that 50 percent of animal and plant species live in tropical rainforests – which account for only 6 percent of the world’s land surface!
The Tropical Rotunda
The Fuqua Conservatory Tropical Rotunda at the Atlanta Botanical Garden maintains a constant temperature of 70 – 72 degrees F and a relatively high humidity. It is constantly monitored by a sophisticated computer program which adjusts temperature or humidity automatically to maintain tropical conditions year-round. Depending on outside weather conditions, the windows may be opening or closing or the mist may be turned on or off on a seemingly random basis.
The Tropical Rotunda is home to a diverse collection of plants from all over the tropical world. Key groups such as palms, ferns, cycads, melastomes, epiphytic plants, tropical conifers and vines are represented. These collections emphasize plant diversity, conservation, and adaptations to specific environments. While exploring the Tropical Rotunda you may encounter a banana or chocolate tree, see roots hanging down from the ceiling and hear live poison dart frogs calling. It is truly a tropical experience!
Plants growing in the tropical rainforest have certain adaptations that help them survive in a dense, wet and sometimes shady habitat. Only 1 – 2 percent of sunlight reaches the forest floor through the thick tree canopy. Many adaptations, such as large, dark green leaves address the need for plants to get sunlight.
Several tropical rainforest plants, such as vines and epiphytes, grow on other plants or trees, which are higher in the tree canopy and closer to sunlight. Certain vines begin growing in the tree canopy and send their roots down to the soil. In the Tropical Rotunda, you will notice roots hanging down from a Cissus vine, which is currently growing along the ceiling of the conservatory. Vines also start growing on the forest floor and grow up and around another tree for support. Often, these vines damage the host tree. On the other hand, epiphytes, or air plants, do not damage their host plant. Examples of epiphytes are orchids, bromeliads and aroids. Their roots wrap around a branch or trunk and receive all the moisture they need from the air instead of from the soil. Bromeliads are particularly interesting because their leaves form a cup shape that holds water. Animals such as poison dart frog tadpoles and insects live inside these plants making them diverse habitats in the treetops.
Soil in tropical rainforest tends to be low in nutrients. As a result, many plants have shallow roots and sometimes even have roots above ground. Since rainforests receive plenty of rainfall, the roots are able to get water from the air or from precipitation instead of accumulation in the soil. Roots above ground are often referred to as stilt, buttress or wormy roots. While walking through the Tropical Rotunda keep your eyes open for exposed roots.
The High Elevation House
Additionally, the High Elevation House in the Fuqua Orchid Center is an excellent place to view tropical plants that live approximately 6,000 – 10,000 feet above sea level. While visiting, think about how the plants in this room look different from those in the Tropical Rotunda. How does this room feel different?
Many everyday resources such as rubber, cinnamon, vanilla, coffee and rattan originate in the tropical rainforest. The Garden has many of these plants on display in the Orangerie in the Fuqua Conservatory. Come visit the Garden to learn more about these plants and explore a tropical rainforest!