Measuring greenhouse gas fluxes from forests and oil palm


Posted by: Melissa Melody Leduning

Melissa, Loly, Arnold, Mus, Sany, Julia and Ute have been busy hammering small rings into the soil at LFE, Fragments B and E 10 ha plots, OP3 (Mawang Estate) and OP plantations on the Menggaris Estate close to the RR14 riparian strip. We do this to measure soil emissions of the greenhouse gases carbon dioxide, methane, nitrous oxide and volatile organic carbon compounds. Installing the frames is not always as easy as it looks, hidden roots and stones mean that we have to try several times to find a suitable location to hammer the frames into the soil. However with the help of our strong RAs (Arnold, Mus, Sany) and Julia we still managed to install 56 chambers much faster than planned. Our chambers arrived by ship from the UK in many large boxes, which were unpacked in no time by a very helpful team of RA’s.

                  Our chambers arrived by ship from the UK in many large boxes, which were unpacked in no time by a very helpful team of RA’s.

We started our first measurements on the 15th January and will repeat these every two month over the next two years. For the flux measurements we place a chamber onto the rings for 45 minutes, periodically withdrawing air samples for nitrous oxide and methane analysis followed by sampling for the volatile carbon analysis. At the same time we take soil samples for microbial, chemical and physical analysis, measure soil respiration rates, soil + air temperature and soil moisture.

Top picture left: Rings were installed in LFE, Fragments B and E, OP3, and oil palm plantations near RR14. The bottom left pictureshows the chamber placed onto the ring and samples removed with syringe and placed into the small glass and for volatile carbon analysis pumped through special adsorption tubes.

Right picture: The fertiliser bags (a large source of nitrous oxide) are visible in the oil palm plantation.

When back at camp we recharge the batteries of our soil respiration analyser and batteries for the pumps, at the same time do wet chemistry to extract the inorganic nitrogen compounds from the soil, write up our notes from the day and prepare vials and soil sample bags for the following day’s measurements. All in all a very busy 6 days for the core team.

The core team are Melissa Leduning from UMS and the RAs Laulina Mansul and Arnold James, Julia Drewer and    Ute Skiba from the Centre for Ecology and Hydrology in the UK were here for installing the measurements and      training the core team, and will come back to support these measurements at regular intervals.

         In the forest plots the chambers are stored in the trees or tied to trees. If you do see a stray chamber or a chamber upside down please tell Arnold or Loly! The chambers for the oil palm plantations are stored in the SAFE camp.

    The team: Melissa, Julia, Arnold and Loly ready to sample in Fragment E.

Our work is funded by the Human Modified Tropical Forest Programme of the Natural Environment Research Council (NERC). We are part of the LOMBOK team, lead by Prof. Owen Lewis. Melissa Leduning is supervised by Dr Justin Sentian at the Universiti Malaysia Sabah. The work described above is part of work package A. WP A focuses on the effect of forest modification (gradient from almost intact forest to mature oil palm) on emissions of the greenhouse gases nitrous oxide, methane, soil respiration of carbon dioxide, biogenic volatile organic carbon emissions and underlying changes in the overall and active soil microbial population. We speculate that the overall greenhouse gas emissions from oil palm are much larger than from the forest ecosystems. Only very few measurements have so far have compared greenhouse gas fluxes from tropical forest ecosystems with oil palm plantations, so our work adds to the global data base and allows better quantification of the greenhouse gas footprint of forest modification.