Fairchild Tropical Garden

Almost every morning at the Fairchild Tropical Garden, water showers through a grove of tall oak trees onto rich jungle greenery below. The droplets come from Rain Bird T-Bird rotors high up in the tree canopies, making this the largest outdoor simulated rain forest in the U.S.

The rain forest thrives in the warm climate of South Miami, Florida, and is among the many botanical wonders at Fairchild Tropical Garden. Named after American plant explorer David Fairchild, the garden displays many rare and endangered species from tropical environments worldwide.

Fairchild features 11 lakes that were excavated when the garden was created, overlooks with beautiful vistas, trails, a new 16,000-square-foot conservatory, and an internationally renowned herbarium and library. Alongside the 2,841 palms and 250-year-old cycads, thrive an extraordinary array of flowering and fruiting trees, shrubs, vines, ferns, bromeliads, orchids and other epiphytes (not to mention an alligator or two).

Designed by landscape architect William Lyman Phillips in 1938, Fairchild is an 83-acre showcase for the largest tropical botanical garden in the continental United States. By exposing the public to these plants, the garden aims to educate and inspire conservation of the rain forests.

The Rain Forest Preserve

"The rain forest is disappearing at an alarming rate throughout the tropics," said Don Evans, Fairchild's Director of Horticulture. "Our rain forest gives us a platform to educate the public about how they can get involved in protecting these environments."

Inside the 2 and 1/2 acre rain forest preserve, vegetation at all levels envelops the visitor. A high canopy of Southern live oaks and palms tower 60 feet above the footpath. Along the lush floor are masses of shade-loving palms, ferns and aroids, including philodendrons, anthuriums and monsteras.

The oak trunks are bare of branches up to forty or fifty feet, but they are not bare of life. Huge rope-like vines cover the trunks, along with ferns, mosses, bromeliads, orchids and other epiphytes, many of which are in magnificent bloom. Up higher in the canopies are many more clusters of orchids and bromeliads.

Restoration After Hurricane Andrew

In 1992, Fairchild lost many old and irreplaceable plants to Hurricane Andrew. It was a catastrophe for the botanical garden and its rain forest, which lost a number of trees, much of its canopy and irrigation system. To the relief of the jungle plants left standing, an upgraded irrigation system was installed in 1995 and restoration of the rain forest began.

All the jungle vegetation requires a very moist, humid environment to flourish. An irrigation system is necessary because a true rain forest receives at least 100 inches of rain throughout each year, which is double the amount that South Florida receives.

To design and install a new system, Fairchild hired Brent Hoover, an engineer and irrigation specialist as well as the president of Hoover Pumping Systems in Pompano Beach, Florida. Hoover faced many unique challenges. Because much of the growth in the rain forest is in the canopy, Hoover needed to design a system that he could install as high as 60 feet above ground. "We wanted to match the conditions of a rain forest," he said, "meaning that water would come from overhead."

Building a Canopy Irrigation System

First, Hoover determined that sprinklers needed to be 40 to 45 feet apart with minimal pressure loss and flow demands. The dense mass of vegetation called for even coverage.

Hoover chose Rain Bird's T-Bird® rotor to do the job. "A smaller head like the T-Bird rotor was ideal," said Kevin Cavaioli, a landscape architect and Hoover's vice-president. "The T-Bird rotor's droplet pattern, even precipitation rate and uniform water distribution were very important. Also, the Rain CurtainTM nozzles break up water into fairly consistent drops to provide moisture for upper story plants."

Hoover's next challenge was to affix one to three T-Bird rotors up into each of the forest's 30 oak tree canopies. To do this, he designed a special mounting bracket that could be screwed into the one-inch thick bark and attached a schedule 80 swing joint assembly to the bracket. The bracket and swing joint make it possible to adjust a T-Bird rotor's position according to a tree's branching pattern.

To furnish water to the T-Bird rotors, Hoover attached UV-resistant polyethylene pipe to the tree trunks. The black pipe is 3/4 to 1 and 1/4 inches in diameter, depending on how many sprinklers are attached. The lateral lines are connected to the schedule 40 mainline pipe, which is buried 12 inches below ground. Hoover screwed a UV-resistant PVC conduit clamp into the bark with galvanized drywall screws every 2 feet to fasten the polyethylene pipe to the trees.

A booster pump increases the water pressure an additional 30 psi, supplying adequate force for the T-Bird rotors. With any other sprinkler head, Hoover would have worried about the possibility of varying pressure affecting water distribution. With the T-Bird rotor and its pressure compensating nozzle, his concerns disappeared.

Hoover divided the irrigation system into three zones, each of which is controlled automatically and run at approximately 45 gpm and 60 psi. Since the sprinklers are difficult to reach, Hoover installed an automatic hydrocyclone filter system to keep them clean. There are also two injection systems, one for fertilization and the other for an acid wash that protects the foliage from a high level of minerals in the water.

Installing the system was an arduous task that included hand digging all trenches to prevent damage to the plants. "The biggest challenge was just getting up into the trees to install the system," said Hoover. "We used boom trucks to lift workers up, and when they couldn't reach, we hired arborists to climb the trees."

"The new irrigation system is working extremely well for Fairchild," said Hoover. "The orchids and all the plants are doing much better." Evans agreed. "The rain forest is flourishing. We have planted some fast growing species and in three or four years the canopy will be full again."