Is it possible to use NDVI to estimate above ground biomass? What options are available when in-situ field data is absent? I work in a semi-arid context.
https://peerj.com/preprints/913v1.pdf
http://www.isprs.org/proceedings/XXXIII/congress/part7/1580_XXXIII-part7.pdf
http://www.afrjournal.org/index.php/afr/article/viewFile/278/362
Remote sensing, in most cases, should be supported or validated by ground observations.
In semi-arid areas of the world it is easy to evaluate above ground biomass, AGB, using remote sensing techniques such as NDVI maps as the relationship between AGB and the signature of the NDVI map do not saturate. AGB can now be easily calculated using any of the many allometric techniques already developed for the area or for the same species of the area. For this use, for example data and equations already published in the FAO homepage of TREE ALLOMETRY can help you to evaluate AGB using only diameter at breast height of the tree species you are evaluating. So you have to measure stem normal diameter, D, and geographically locate several (lets say between 20 and 50 trees) the trees. D is converted to AGB using the allometric equations and the NDVI map has a signature of the tree. Correlate AGB and the signatura and expand to the area f interest. There you have your evaluation of AGB in Mg ha-1 for the area.
Should you have further questions please do not hesitate to contact me at your earliest convenience.
Kind Regards
Sincerely
Jose Navar, Ph.D
Thank you Jose Navar, Xingwang Fan and Firoz Ahmad for all your contributions, comments and valuable information.
Thank you Jose for providing very informative detail of AGB. I am also working on similar project and your information is very helpful for me.