ISSN 2375-0979
African Journal of Wood Science and Forestry ISSN 2375-0979 Vol. 3 (9), pp. 198-210, September, 2015. © International Scholars Journals
Full length Research Paper
Depicting forest cover in Grand South of Cameroon: An analysis based on L-band PALSAR 50-m orthorectified imagery
Simon Njeudeng Tenku1*, Xiangming Xiao2 and Jinwei Dong2
1Institute of Agricultural Research for Development (IRAD), Regional Centre for Agricultural Research Nkolbisson (CRRANK), P.O Box 2123, Yaoundé Cameroon
2Department of Microbiology and Plant Biology, and Centre for Spatial Analysis, University of Oklahoma, Norman, OK 73019, USA.
*Corresponding Author: Email: [email protected]
Accepted 14 August, 2015
Abstract
Up-to-date information on forest cover is important for every country. Radar remote sensing technology has considerable potential to acquire cloud-free images in moist tropical forests due to frequent cloud cover. The objective of this study was to investigate the potential of Phased Array Type L-band SAR (PALSAR) imagery for forest cover mapping. 50-m orthorectified mosaic image of 2009 from L-band PALSAR was used for the study. Geo-referenced field photos were taken as ground truth data points and were organized to obtain regions of interest. K-means and decision tree classifications were carried out to discriminate forests from other land covers. Decision tree algorithm was more reliable than K-means and showed an overall accuracy assessment of 91.7 % and Kappa coefficient of 0.86. Decision tree estimated 24.4 million hectares of forests, that is, 12.5 % higher than 21 million hectares reported by ITTO in 2011. L-band PALSAR modelled backscatter output for the difference phase showed a grey tone pattern for forest cover similar to that of decision tree than to K-means; implying a spatial reliability for the modelled phase. Improved PALSAR-based forest cover mapping necessitates data coverage in both rainy and dry seasons.
Keywords: Remote sensing; forest cover mapping; PALSAR 50 m; field photo library; image texture.