Analysis of conifer forest regeneration using Landsat Thematic Mapper data

Landsat Thematic Mapper (TM) data were used to evaluateyoung conifer stands in the western Cascade Mountains ofOregon. Regression and correlation analyses were used todescribe the relationships between TM band values and ageof young Douglas-fir stands (2 to 35 years old). Spectral datafrom well regenerated Douglas-fir stands were compared tothose of poorly regenerated conifer stands. TM bands 1, 2, 3,5, 6, and 7 were inversely correlated with the age (r— 0.80) of well regenerated Douglas-fir stands. Overall, the"structural index" pm 4/5 ratio) had the highest correlationto age of Douglas-fir stands (r = 0.96). Poorly regeneratedstands were spectrally distinct from well regenerated Doug-las-fir stands after the stands reached an age of approxi-mately 15 years.