Traceability of slash-and-burn land-use history using optical satellite sensor imagery: a basis for chronosequential assessment of ecosystem carbon stock in Laos

• Published in: International journal of remote sensing Vol. 28; no. 24; pp. 5641 - 5647
• Main Authors: Inoue, Y., Qi, J., Olioso, A., Kiyono, Y., Horie, T., Asai, H., Saito, K., Ochiai, Y., Shiraiwa, T., Douangsavanh, L.
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 20.12.2007; Taylor and Francis
• Subjects: Agronomy. Soil science and plant productions; Applied geophysics; Biological and medical sciences; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; Generalities. Biometrics, experimentation. Remote sensing; Internal geophysics; Remote sensing; Far East; Asia; Laos; wavelength; Thematic Mapper; Vegetation index; polygons; Space remote sensing; Landsat; accuracy; Shifting cultivation; measurement sensor; storage; classification; agriculture; evaluation; Traceability; land use; carbon; Crop rotation; ecosystems; imagery; segmentation; Spectral index; land cover; Anthropogenic factor; Reflectance
• ISSN: 0143-1161; 1366-5901
• DOI: 10.1080/01431160701656323

This study examined the use of satellite sensor imagery for chronosequential assessment of land use and ecosystem carbon stock in slash-and-burn (S/B) regions of Laos. The segmentation approach was useful because the boundaries of S/B patches are subject to change due to natural or anthropogenic factors. Polygon-based classification using six optical bands of Landsat Enhanced Thematic Mapper Plus (ETM+) imagery showed that S/B patches could be discriminated with high accuracy (0.98). Normalized difference spectral indices, NDSI[i, j] = [R j −R i ]/[R j +R i ], using reflectances R j and R i at j and i nm wavelengths for S/B polygons during four consecutive years (1999-2002) showed that NDSI[2215, 830], NDSI[1650, 830] and NDSI[660, 830] ( = the normalized difference vegetation index, NDVI) values decreased significantly in S/B years compared to those under fallow conditions (by 0.21±0.04, 0.20±0.04 and 0.17±0.03, respectively). Only slight differences were found before and after the S/B year, regardless of fallow length or biomass estimated by the allometry method. Relating reflectance signatures directly to fallow biomass was unsuitable, but these NDSIs were also useful for distinguishing S/B patches. Land-use history, including the community age of fallow vegetation, can be traced on a pixel basis using a superimposed set of segmented classified images.