STAND DISCRIMINATION IN A WESTERN CONIFEROUS FOREST
USING AIRSAR DATA
José L. Saleta
Masters Thesis, Department of Geography, University of California,
Santa Barbara. 148 pp. 1995.
The capability of airborne synthetic aperture radar
(AIRSAR) in the discrimination and classification of coniferous forest
stands following the criteria that the US Forest Service uses to elaborate
timber stand maps (i.e. percentage of canopy cover and average crown
size) was evaluated. Discriminant analysis and a decision tree classifier
were used to analyze data from 258 stands on a ponderosa pine forest
near Mt. Shasta, California. The data analyzed consisted of backscatter
coefficients at HH, VV and HV polarizations and like-polarization
phase difference at C-, L- and P-bands. A set of ratios derived from
these was also tested. Data from two dates with wet and very dry ground
conditions were examined. Only limited discrimination of stands could
be achieved using SAR images. C-HV, L-HV, P-HH and P-VV were the most
useful channels, with classification accuracies that range from 42
to 49%. Among the derived ratios, the woody vs. herbaceous indices
and the P-band biomass index were the most significant variables,
with classification accuracies between 39 and 47%. The analyses were
repeated aggregating the 8 stand types into the 3 timber volume classes
considered by the USFS. The classification accuracies raised then
to 72-77%, but class separation using discriminant analysis did not
improve significantly.