Jeff Chambers’ path to the Amazon forest started 20 years ago in an unlikely place: Livermore, California. Since then, he has bushwhacked through dense woodland, traveled hundreds of miles down jungle rivers, had close encounters with the world’s most painful ant and near misses with deadly snakes—all in the name of science.

Chambers studies trees—dead and alive. Or rather, more scientifically, he studies the ecology and carbon cycling in forested ecosystems and has become an expert in tree mortality, which can have a major impact on the global carbon cycle.

“For every ton of CO₂ we emit to the atmosphere, only half stays in the atmosphere. The other half goes in the ocean and in the land for some unknown period of time,” he says. “Some scientists estimate that more than half of this terrestrial sink is in old-growth tropical forests, so it’s very important to understand exactly what role these forests are playing in carbon sequestration.”

Chambers, a scientist in Berkeley Lab’s Earth Sciences Division, grew up in Santa Cruz and earned a Ph.D. in ecology at UC Santa Barbara. While still a first-year grad student, he started working with a group at Lawrence Livermore National Laboratory with a first generation Earth system model. He focused on modeling terrestrial ecosystems. “A lot of the model uncertainties were in the tropics,” he says. “In particular we didn’t know anything about the rate at which trees were dying naturally, and how fast they would decompose and release CO₂ to the atmosphere.”

So Livermore sent him to the Amazon and continued to support his work for five years. “It’s probably one of the craziest things they’ve ever done,” he jokes.

Twenty years later, he speaks fluent Portuguese and is still going to the Amazon four or five times a year. He has an appointment at the National Institute for Amazon Research (Instituto Nacional de Pesquisas da Amazônia [INPA]) in Manaus in northern Brazil, which serves as home base for projects in the forest.

“It’s extremely challenging to get into some of these field sites,” he says. “It’s not for the fainthearted. Some trips are 10, 12, even 20 hours by boat—and that’s on a fairly fast boat. When building new sites, it’s like backpacking. You get attacked by army ants, bullet ants. You get bitten by wasps. There are snakes and diseases. You sleep on hammocks for days.”

Chambers once had a bushmaster, one of the longest and most venomous snakes in the western hemisphere, strike between his legs while he was marching through the forest—twice—and didn’t even realize it until his ashen-faced colleague told him. Another time he was bit three times by a bullet ant. “If you look it up it’s the most painful insect sting on planet Earth,” he says. “It’s like a super sharp flash of pain, incredibly intense, that slowly diminishes over the next 24 hours.”

They do work with local guides, known as mateiros, or foresters, whom Chambers says are impressive self-taught botanists, can build a shack from downed logs in just over a day and climb hundred-foot-tall trees in minutes.

And Amazon food, apparently, is out of this world. Some of his favorites include the Tambaqui fish, fattened on tree fruits and nuts they chomp on after the rainy season puts them within meters of the treetops, and tucumã, a bright orange palm fruit often served with tapioca pancakes. “Just thinking about it right now I’m dying for one,” he says.

Read about his latest Amazon research here and his work on hurricane-related damage here.