OSU scientist, students eye carbon in tropical forests

July 22, 2002
OSU scientist, students eye carbon in tropical forests
OSU scientist, students eye carbon in tropical forests

CORVALLIS - Despite ravenous ants, poisonous snakes, thieving monkeys and hellish temperatures, Boone Kauffman and his students remain intent on unlocking secrets of tropical forests.

The goal of their two-year-old research project, in parts of Costa Rica that range from coastal lowlands to cloud-draped mountains, is to nail down some specifics on the potential for a new kind of global commerce - carbon trading.

"We're part of a multi-institutional, interdisciplinary team funded by the National Science Foundation that's trying to quantify the role of tropical forests in the global carbon cycle," said Kauffman, an ecologist in Oregon State's Department of Fisheries and Wildlife.

"Our specific job is to measure the carbon stored, or sequestered, in various types of tropical forests," said Kauffman. "Another phase of our job is to measure the carbon stored in lands that used to be tropical forests, like banana and coffee plantations and cattle pastures, so scientists can calculate the quantity of carbon loss associated with forest conversion, as well as the potential of lands in those kinds of uses to serve as carbon 'sinks,' or reserves.

"The third phase is looking at lands formerly converted from forests to other uses that are abandoned and regrowing into forests," the OSU scientist said. "We're studying soil and plant growth characteristics in these secondary forests and measuring how much carbon is sequestered by the growing trees each year."

Kauffman returned to Oregon recently after almost nine months in Central America.

"Costa Rica is ideal for our research because of the diversity of its soils and forest types," he said. "The forests there range from tropical dry forests, or savannas, to cloud forests that get up to 21 feet of rain a year and are among the wettest ecosystems on earth. You could easily visit six different types of tropical forests in Costa Rica in a day."

The scientist and the two graduate students and six undergraduates who worked with him last winter during the project's second field season spent most of their days in lush, tangled patches of forests just a little bigger than a football field.

"Our job was to measure all the organic matter in this plot, everything - the mass of the trees, dead wood, leaves and the soil down to a meter," said Kauffman.

This fieldwork, plus sleeping in national parks and on farms when they weren't at little out-of-the-way hotels, led to memorable encounters with nature.

Often they had to start before dawn, trying to complete their work before the temperature reached 100 degrees, with humidity near 100 percent.

"We saw four types of venomous snakes," said Kauffman. "Spider monkeys harassed us. One got in our van and ate our lunches. There were several kinds of scorpions in the huts where we stayed at Santa Rosa National Park." That is, until millions of army ants trooped through, devouring those and any other insects they could catch.

Implications of the research make the hardships worthwhile, Kauffman believes. Carbon, in the form of carbon dioxide gas, has been linked to a build-up of energy in the earth's atmosphere and global warming - the Greenhouse Effect.

Land conversion leading to the loss of tropical forests is believed to be second only to burning fossil fuels as a source of greenhouse gases in the atmosphere, according to Kauffman. If forests are allowed to regrow, he explained, trees absorb carbon dioxide out of the atmosphere through photosynthesis and store it as wood or soil organic matter.

"If you look at the Kyoto Protocol (the outcome of a 1997 United Nations-sponsored meeting on global climate change), it gives developed and developing countries the potential to buy and sell carbon credits," said Kauffman. "So, for example, one country can pay another to use land management practices that sequester carbon from the atmosphere. This gives the purchaser the right, or credit, to release a certain amount of carbon into the atmosphere.

"But we need a lot more specifics on how much carbon is stored in various kinds of tropical forest ecosystems," he added.

In addition to the value of the data Kauffman's group is collecting to countries interested in swapping carbon credits, and to landowners wondering how much their property is worth as a carbon sink, the data eventually could feed into the work of the United Nation's International Panel on Climate Change.

There's another year of field work ahead for Kauffman, who plans to employ students from Oregon State University and a Costa Rican institution next year. But already, the findings are surprising.

"For example," he said, "it's typically thought that most of the carbon in tropical forests is above ground. We're finding that more than 50 percent is below ground in decomposing organic matter. We're finding that the wettest forest, the cloud forests, have the most carbon. In terms of how much carbon forests store, we're finding that the density of trees is as important as the size of the trees."

The project has another face.

"We're not only engaged in scientific discovery," said Kauffman, "we're educating the next generation of tropical ecologists. I've seen some pretty good scientists and students move from the temperate zone to the tropics and melt because of the heat, insects, cultural differences, limits to transportation, etc. The OSU students performed remarkably well while learning a great deal about tropical ecology and land use."

And if the Oregon State students who went to Costa Rica, for living expenses and academic credit, decide to pursue careers in such research, there will be plenty more challenges and opportunities waiting for them, Kauffman predicts.

"The same type of work we're doing in tropical forests, measuring carbon pools and their fates associated with forest and land uses, needs to be done in the temperature forests like those in the Pacific Northwest, in the boreal (northern) forests, on the world's grasslands and in the oceans," he said.

Author: Andy Duncan
Source: Boone Kauffman