Revista Chilena de Historia Natural 84 (4): 509-521, 2011
RESEARCH ARTICLE
Quantitative remote sensing to estimate basal area in Nothofagus pumilio
(Nothofagaceae) forest: The role of leaf area index as ancillary information
GASTÓN M. DÍAZ, DIEGO MOHR-BELL, JOSÉ D. LENCINAS, MARCOS MENGER & HÉCTOR F. DEL
Lenga forests (Nothofagus pumilio) are the most important forest
resource of the Argentinean Andean Patagonia, however, more information about their structure is needed to implement
forest management policies and practices in order to prevent their degradation and revert it. One option to obtain this kind
of information is to relate satellite data to the forest characteristics. Nevertheless, which is the most efficient estimation
methodology? Leaf area index (LAI) is related to the canopy reflectance through radiative transfer model PROSAIL,
allowing the development of LAI physical based estimation techniques, instead of statistical models. Therefore, the
empirical biological relationship between LAI and the forest structure can be used to estimate structural parameters, as
basal area. The aim of this study was to compare the accuracy of three different approaches to estimate basal area using
SPOT-5 data. The approaches compared were: direct statistics (ED), two steps statistics (E2P), and two steps physics-
statistics (FE2P). Accuracy assessment was done with 24 independent field measurements. The difference in accuracy was
not statistically significant, i.e., the physical-statistical model was not more accurate than the purely statistical model.
However, based on analysis of other authors evidence and the results of this study, the conclusion was that the advantage of
using physical model, lies on the greater robustness, and not on the better accuracy.
forest
inventory, high resolution satellite imagery, NDVI, PROSPECT, SAIL
