From the Castle

Could we invent a global stethoscope to check our planet's health? The Smithsonian Tropical Research Institute (STRI) will use rain forests to do just that—measuring changes in the amounts of carbon dioxide (CO2) inhaled by three million trees in 20 study plots in 15 countries worldwide—thanks to an $8 million grant from HSBC Holdings and a commitment of more than $10 million from the Frank Levinson Family Foundation.

When trees absorb CO2, they remove it from the atmosphere, thereby reducing the amount of gas in the air and its role in global warming. Over the next five years, the Smithsonian's Global Earth Observatories Program will measure this absorption. Can forests reduce global warming while restoring degraded lands? What are the differences between native and plantation forests in promoting biodiversity and ensuring fresh, clear water?

A full array of Smithsonian scientists and collaborators will investigate the effects of climate change on forest animals, plants and microbes. Peering into the distant past through paleontological and genetic analysis, they will measure biodiversity through time. Specialists at the Smithsonian's Astrophysical Observatory and the National Air and Space Museum will monitor forest health from space.

This far-reaching project dates back to 1979 when Smithsonian ecologists began to map and measure every tree with a diameter wider than a pencil in 120 acres of a forest on Barro Colorado Island, STRI's biological reserve in Panama. That study plot—today the most intensely studied rain forest on earth—had more than a quarter-million trees, representing 300 species. Five years later, the scientists counted the trees again and documented remarkable and unexpected forest dynamics. Roughly 40 percent of the tree species had decreased in number by more than 10 percent, apparently as a result of droughts that multiplied death rates by up to 20 times that of non-drought years. The finding has led to a new theory of biodiversity and galvanized a spirited debate on the role forests along the Panama Canal play in regulating its water.

By 1990 scientists around the globe had replicated the STRI methods, and a network of study plots emerged, operated in each country by one or more partner institutions, for example the Indian Institute of Science. The resulting Smithsonian Institution Global Earth Observatories Program now involves hundreds of scientists from more than two dozen institutions. As Dr. Levinson puts it: "Clear, long-term information-gathering about the dynamics of the tropical forest is essential if we are to build ecological, climate or biodiversity models that have predictive power."