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Lookup NU author(s): Professor Yit Arn TehORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Large-scale conversion of tropical peat swamp forests to agricultural plantations has resulted in substantial carbon dioxide (CO2) emissions. Despite consensus on the importance of these emissions, the cause of the large range in the magnitudes of reported values remains uncertain. Differences in reported fluxes might result from site specific factors and/or potential limitations of the manual flux chambers commonly used. It is important that any biases at the site level are explored as they ultimately affect regional and global emission estimates. Therefore, the aim of this study is to determine if measurement timing of commonly used infrequent manual chamber measurements leads to biased emission estimates. In this study we make use of six months of automated chamber data to provide a semi-continuous timeseries. This timeseries is used to explore the potential for time-of-day sampling biases in infrequent, monthly manual chambers measurements in a peatland oil palm plantation in Malaysian Borneo. Fluxes from Palm Base, Harvest Path, Frond Pile, Drain and Inter row microforms were recorded hourly using automatic chambers. From these hourly data, mean diurnal patterns of fluxes were produced. These diurnal patterns were used to characterize the biases in a larger, monthly flux manual chamber dataset. This monthly manual dataset was collected over six years at the same site and microforms, with individual measurements made in the daytime. Bias range was widest for Harvest Path (-18 to 24 %), followed by Palm Base (-13 to 11 %), Drain (-10 to 9 %) and Frond Pile (-5 to 3 %). Estimates of annual plantation scale emission over six years, corrected for sampling bias ranged from 36 - 53 Mg CO2 ha(-1) yr(-1). We recommend careful consideration of artefacts sample timing might introduce in any sampling design, and where possible fluxes should be corrected with measured diurnals for each microform considered.
Author(s): Basri MHA, McCalmont J, Kho LK, Hartley IP, Teh YA, Rumpang E, Signori-Müller C, Hill TC
Publication type: Article
Publication status: Published
Journal: Agricultural and Forest Meteorology
Year: 2024
Volume: 350
Print publication date: 01/05/2024
Online publication date: 09/04/2024
Acceptance date: 06/04/2024
Date deposited: 04/12/2024
ISSN (print): 0168-1923
ISSN (electronic): 1873-2240
Publisher: Elsevier BV
URL: https://doi.org/10.1016/j.agrformet.2024.110002
DOI: 10.1016/j.agrformet.2024.110002
Data Access Statement: Data will be made available on request.
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