Rainforest canopy reveals its secrets

18 September 2008 by Tom Marshall

A research expedition involving 60 scientists and support staff descended on the rainforests of the remote state of Sabah in Borneo in July.

FAAM aircraft flying over Malaysian jungle

The NERC/Met Office BAe 146 research aircraft swooping low over Malaysian rainforests

A research expedition involving 60 scientists and support staff descended on the rainforests of the remote state of Sabah in Borneo in July.

The team used a low-flying research aircraft and ground-based instruments to investigate how the rainforest influences the chemical composition of the air above it.

The group, made up of scientists from the UK, Malaysia and Italy, believe the campaign may be the first to link closely such detailed ground-based and airborne measurements simultaneously over a rainforest.

Pilots swooped low over the canopy following a flight path that took them below the forest on surrounding hills.

The research, which is part of the £1·9m three-year OP3 project, short for 'Oxidant and particle photochemical processes above a South-east Asian tropical rainforest', was led by Nick Hewitt, professor of atmospheric chemistry at Lancaster University.

The consortium based itself at two sites: the Bukit Atur Global Atmospheric Watch research station in Danum Valley and Kota Kinabalu international airport, a short flight from Danum Valley.

Plant emissions

They measured emission rates of chemicals coming from the forest canopy, in particular isoprene, a volatile organic compound. Scientists think isoprene protects plants against stress, for example heat stress on hot days, but it is also an important component of global atmospheric chemistry. The measurements will be used in models of local, regional and global atmospheric chemistry and climate.

"We want a better idea of what happens to these reactive gases in the atmosphere, how they influence ozone and other oxidants, and whether they form particles in the atmosphere," said Hewitt. The consortium has already made a 'significant' finding.

"We saw big differences between the atmospheric composition above rainforests and the composition over oil palm plantations," Hewitt reported.

Oil palm, a good source of food and biofuel, is a big industry in the region. Plantations are replacing rainforests throughout the tropics. The implications of the research will become clearer in the next 12 months.

The team think it likely the project will inform Malaysian scientists and planners on the connections between South-east Asian tropical forest and climate, supporting Malaysian research and policy on sustainable forest management.

The OP3 consortium involves ten Malaysian institutes and scientists from the universities of Lancaster, Leicester, Cambridge, York, Leeds, Manchester and East Anglia and the Centre for Ecology & Hydrology, Edinburgh. It is due to finish in 2010.

The research aircraft, a BAe 146, is operated by NERC's Facility for Airborne Atmospheric Measurements, funded jointly by the Met Office and NERC.