Changing carbon dioxide and water budgets from deforestation and habitat modification

 Project Details
Title: Changing carbon dioxide and water budgets from deforestation and habitat modification
Researchers: Terhi Riutta, Yadvinder Malhi, Donis Gunting
Email: terhi.riutta@ouce.ox.ac.uk
Nationality: International

 Sampling details and required resources
Spatial Scale: Other
Sampling Sites: Other
Time Frame: 1 November 2011 until 31 December 2015
Resources: Research Assistant(s), Vehicle, Other : flux tower

 Rationale and questions
Land use change of tropical forest contributes approximately 12% to the global anthropogenic carbon emissions. Over the period of 2000-2005, the carbon emissions from land use change in tropical forest biome was 1.30 ± 0.24 Pg C year-1, of which almost 50% was from Asia (Malhi 2010, Current Opinion in Environmental Sustainability 2:237 244). The main sources of CO2 from land use changes are the loss of live biomass and the loss soil carbon. In this project, we aim to quantify the impact of forest conversion on fluxes of carbon dioxide (CO2), water (H2O) and energy. The measurements are conducted at the ecosystem scale before, during and after the conversion to oil palm. This project provides a detailed assessment of CO2 uptake and emission rates under different land uses. The data can be combined with the other SAFE projects, which are investigating net primary productivity and carbon and water budgets.

 Methods
We employ eddy covariance technique for continuous, non-invasive measurements of CO2, H2O and energy exchange between the ecosystem and the atmosphere. Fluxes are measured above the canopy, from a 50m high flux tower, with a fast-response infrared gas analyser and 3D sonic anemometer. The covariance between vertical wind speed and CO2 / H2O concentration is equal to the net exchange of CO2 / H2O between the ecosystem and the atmosphere. The fluxes are averaged over 30-min time periods and provide a continuous time-series. Therefore, we can estimate the net CO2, H2O and energy balance of the ecosystem on daily, monthly and annual time scales. Eddy covariance technique integrates the fluxes originating from a large area, thus representing CO2 dynamics at the ecosystem scale. The measured fluxes represent an average exchange rate from an area upwind from the flux tower. The source area varies continuously with atmospheric stability, wind speed and direction. At the SAFE site, the flux tower is located near Fragments B and D, in the area that will be converted to oil palm. The source area extends to several hundred metres upwind from the tower in typical conditions. Weather stations both above and below the canopy provide continuous data on air temperature, air pressure, humidity, radiation, soil temperature and soil moisture.

Output Files