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WIRELESS MEASUREMENT SYSTEM: Researchers at the La Selva Biological Station in Costa Rica are constructing wireless access to measurement systems to collect and transmit data and provide a dynamic 3-D analysis of the rainforest canopy.
Courtesy of UCLA CENS

For more than half a century, the La Selva Biological Station in Costa Rica has provided researchers with the data needed to study everything from local amphibian and reptile populations to global warming. To meet a growing demand for La Selva's treasure trove of biological and environmental data, the main facilities are getting a $785,000 high-tech makeover that includes wireless access to measurement systems that collect and transmit data and provide a dynamic 3-D analysis of the rainforest canopy.

The Center for Embedded Networked Sensing (CENS) at the University of California, Los Angeles, plans to develop and expand its mobile sensor platforms and sensor arrays as well as the information technology and infrastructure used to store and share the collected information. The upgrade—funded by the National Science Foundation—will enable researchers to take core microclimate measurements and precise wind measurements as well as measure carbon dioxide (CO2) differences up through the rainforest's canopy. It will also be used to set up networks of video and acoustic monitoring capabilities for animal and plant studies.

"We're getting cutting-edge technology that's never been used before," says Philip Rundel, a U.C.L.A. biology professor and ecologist studying ecosystem dynamics and carbon flux at La Selva. "One of the most challenging things in a rainforest is that there's more diversity off the ground than on the ground. Access to this has always been a problem."

The project's main goal is to collect large amounts of data such as temperature, humidity, CO2 and solar radiation from sensors placed throughout a five-acre (two-hectare) study area in the La Selva rainforest. This data can then be used to analyze the spatial and temporal dynamics of environmental conditions, including baseline data for global climate change and their relevance to changes in regional land use patterns. Rundel and his team will use LabVIEW software from Austin, Tex.–based National Instruments Corporation to analyze microclimate patterns and carbon flux over a specific area of the forest.

National Instruments also supplies the controllers used in the researchers' fixed and mobile measurement platforms, with the latter able to move above the forest's 98-foot- (30-meter-) high canopy like high-wire walkers along cables connecting three 148-foot- (45-meter-) tall towers. Rundel and his team are in the process of erecting a group of four new towers and a canopy walkway system, along with installing the fiber-optic cables and power lines that will stretch approximately 1,640 feet (500 meters) from the site back to the laboratory (where the system's computer servers will be located).

Rundel wants researchers to have wireless access from both sets of towers, although he acknowledges that Wi-Fi is unpredictable in such remote regions. "A lot of radio waves are uncertain in terms of how they will carry through the forest," he says. "It will take some testing to see how broad the area of wireless will be."

The researchers are particularly interested in the carbon cycle, the uptake of CO2 by plants as they grow and the recycling of some of this carbon back into the atmosphere via respiration. Tropical rainforests are thought to play an important role in reducing the amount of atmospheric CO2. The European Union allows its member nations' industries to buy what are known as "carbon credits" as part of a plan to cap total annual greenhouse gas emissions and give them a monetary value. A significant amount of the money used to buy these credits is administered by the Costa Rican government, in the form of foreign aid from the E.U., to pay landowners to plant or maintain tropical forests, Rundel says. But the carbon dynamic in these forests is not fully understood, making it difficult to know how well this plan is reducing atmospheric levels of CO2.

A major area of uncertainty lies with the environmental factors that control rates of CO2 loss from forest soils and decaying organic matter. Rundel suspects that the fluctuations in carbon emissions are in part due to tree-fall gaps in the forest that act as chimneys for gas loss. "But this is all hypothesis because no one's been able to measure within such gaps," he says. "We want to put up a multitower array with connecting cables so we can instrument these gaps [where CO2 may be leaking]" and use this intelligence to inform governments how to move forward with their efforts to control climate change.