The Tangled Roots of the Amazon Forest
By Karl Leif Bates
U-M News Service
Robyn Burnham Ph.D.
Robyn Burnham's conversation bends and loops, soars and dives in a most appealing way — not unlike her beloved tropical vines at the headwaters of the Amazon River in the Peruvian Andes.
Relatively slight, and decidedly parasitic, these lianas—or woody vines—that Burnham studies at the foot of the Andes have been largely ignored by the botanists and global change experts trying to measure the health of the Amazon basin. Yet lianas account for 20 to 25 percent of the plant species, and five to 10 percent of all the biomass of the Amazonian forest.
In this sense, Burnham has her work cut out for her. There are an estimated 500 species of woody vines in the equatorial forest, 47 species alone in a single genus. “This is the first place that vines have been looked at, and it's the deep end of the pool,” Burnham says. “I shouldn't have started there!”
Burnham's work on quantifying lianas and trying to understand their role in the forest canopy grew out of her studies of fossil leaves 10,000 feet above sea level in the Andes. There, she realized that vines had been a major player in the ancient forest and probably still are.
Her research entails finding and tracing the path of a two-inch stem from its roots to its fruits, which may be hundreds of feet up and away in a tangled, drippy, potentially malevolent forest. Whereas some researchers merely count stems and guesstimate the total biomass of all vines together, Burnham's methodical work reveals important details, such as which species of vine are thriving and which are minor players in the competition for precious sunlight. She classifies her vines as “the kings, oligarchs, and proletariats,” of the forest.
The King of the lianas, Machaerium cuspidatum, in a rare display of its single-seeded, winged fruit.
In addition to the relentless heat and mud she contends with while conducting her research, there are also mosquitoes, biting spiders, and a 1½-inch black ant the locals call “the eight-hour ant” because that's how long your limb will be useless after a bite. Standing trim and tough at five feet two inches, Burnham does admit a loathing for snakes, but quickly adds that those baby Anacondas frolicking in puddles outside the camp outhouse last year were awfully cute.
With all these hazards involved, it certainly would be easier to study the plants from afar, but Burnham won't hear of it. “Just looking up at a vine with binoculars won't do it,” she says, “because then you can't tell if the leaves you're seeing actually belong to the stem on the ground.”
She also waxes poetic about the beauty of the plants, and recalls the dreamlike sighting of a brilliantly spotted jaguar that swam across a river, then shook itself dry on the bank, creating a fleeting rainbow. “I hope I remember that accurately. It was just so beautiful!”
In addition to surveyin relatively undisturbed forest pots in the Yasuní National Park in Ecuador, Burnham has been measuring the recovery of circular helicopter landing sites that were carved into the canopy years and decades ago by oil company exploration.
As long as it's still alive, the forest manages to adapt and recover. “The spots that were cleared for oil exploration may still be okay, given enough time,” Burnham says. “The question is, what degree of human destruction is okay?”
